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Sample records for anopheles kerteszia em

  1. Studies on Anopheles (Kerteszia) homunculus Komp (Diptera: Culicidae)

    DTIC Science & Technology

    2009-01-01

    ITS2) region of the nuclear rDNA cistron has been widely employed in molecular systematic studies of Anopheles at the species level (e.g. Li and... molecular characterization. The second internal transcribed spacer (ITS2) of the nuclear rDNA cistron was sequenced for six individuals of An. homunculus...among the clones from Colombia needs further investigation by sequencing ITS2 from a larger sample size. Finally, morphological and molecular evidence

  2. Morphology of the larvae, male genitalia and DNA sequences of Anopheles (Kerteszia) pholidotus (Diptera: Culicidae) from Colombia

    PubMed Central

    Escovar, Jesús Eduardo; González, Ranulfo; Quiñones, Martha L; Wilkerson, Richard C; Ruiz, Fredy; Harrison, Bruce A

    2014-01-01

    Since 1984, Anopheles (Kerteszia) lepidotus has been considered a mosquito species that is involved in the transmission of malaria in Colombia, after having been incriminated as such with epidemiological evidence from a malaria outbreak in Cunday-Villarrica, Tolima. Subsequent morphological analyses of females captured in the same place and at the time of the outbreak showed that the species responsible for the transmission was not An. lepidotus, but rather Anopheles pholidotus. However, the associated morphological stages and DNA sequences of An. pholidotus from the foci of Cunday-Villarrica had not been analysed. Using samples that were caught recently from the outbreak region, the purpose of this study was to provide updated and additional information by analysing the morphology of female mosquitoes, the genitalia of male mosquitoes and fourth instar larvae of An. pholidotus, which was confirmed with DNA sequences of cytochrome oxidase I and rDNA internal transcribed spacer. A total of 1,596 adult females were collected in addition to 37 larval collections in bromeliads. Furthermore, 141 adult females, which were captured from the same area in the years 1981-1982, were analysed morphologically. Ninety-five DNA sequences were analysed for this study. Morphological and molecular analyses showed that the species present in this region corresponds to An. pholidotus. Given the absence of An. lepidotus, even in recent years, we consider that the species of mosquitoes that was previously incriminated as the malaria vector during the outbreak was indeed An. pholidotus, thus ending the controversy. PMID:25075785

  3. Isoenzymatic analysis of four Anopheles (Kerteszia) bellator Dyar & Knab (Diptera: Culicidae) populations.

    PubMed

    de Carvalho-Pinto, Carlos José; Lourenço-de-Oliveira, Ricardo

    2003-12-01

    Anopheles bellator is a small silvatic bromelia-breeding mosquito and is a primary human malaria vector species in Southern Brazil. The bromelia-breeding habitat of the species should accompany the Atlantic forest coastal distribution, where bromeliads are abundant. Nonetheless, records on An. bellator collections show a gap in the species geographical distribution. An. bellator has been recorded in Southern Brazil and in the Brazilian states of Bahia and Paraíba. It appears again in the island of Trinidad, in Trinidad and Tobago. The aim of this work was to measure gene flow between different populations of An. bellator collected in the northern and southern extremes of the geographic distribution of this species. Mosquitoes were captured in forest borders in Santa Catarina, São Paulo, and Bahia states in Brazil and in the island of Trinidad in Republic of Trinidad and Tobago. Genetic distances varied between 0.076 and 0.680, based on enzymatic profiles from 11 distinct isoenzymes. Results indicate the existence of low-level gene flow between Brazilian populations of An. bellator, and a gene flow was even lower between the Brazilian and the Trinidad populations. This finding lead us to hypothesize that An. bellator did not spread along the coast, but reached northeastern areas through inland routes.

  4. Anthropophilic biting behaviour of Anopheles (Kerteszia) neivai Howard, Dyar & Knab associated with Fishermen's activities in a malaria-endemic area in the Colombian Pacific.

    PubMed

    Escovar, Jesús Eduardo; González, Ranulfo; Quiñones, Martha Lucía

    2013-12-01

    On the southwest Pacific Coast of Colombia, a field study was initiated to determine the human-vector association between Anopheles (Kerteszia) neivai and fishermen, including their nearby houses. Mosquitoes were collected over 24-h periods from mangrove swamps, marshlands and fishing vessels in three locations, as well as in and around the houses of fishermen. A total of 6,382 mosquitoes were collected. An. neivai was most abundant in mangroves and fishing canoes (90.8%), while Anopheles albimanus was found indoors (82%) and outdoors (73%). One An. neivai and one An. albimanus collected during fishing activities in canoes were positive for Plasmodium vivax , whereas one female An. neivai collected in a mangrove was positive for P. vivax . In the mangroves and fishing canoes, An. neivai demonstrated biting activity throughout the day, peaking between 06:00 pm-07:00 pm and there were two minor peaks at dusk and dawn. These peaks coincided with fishing activities in the marshlands and mangroves, a situation that places the fishermen at risk of contracting malaria when they are performing their daily activities. It is recommended that protective measures be implemented to reduce the risk that fishermen will contract malaria.

  5. Anthropophilic biting behaviour of Anopheles (Kerteszia) neivai Howard, Dyar & Knab associated with Fishermen’s activities in a malaria-endemic area in the Colombian Pacific

    PubMed Central

    Escovar, Jesús Eduardo; González, Ranulfo; Quiñones, Martha Lucía

    2013-01-01

    On the southwest Pacific Coast of Colombia, a field study was initiated to determine the human-vector association between Anopheles (Kerteszia) neivai and fishermen, including their nearby houses. Mosquitoes were collected over 24-h periods from mangrove swamps, marshlands and fishing vessels in three locations, as well as in and around the houses of fishermen. A total of 6,382 mosquitoes were collected. An. neivai was most abundant in mangroves and fishing canoes (90.8%), while Anopheles albimanus was found indoors (82%) and outdoors (73%). One An. neivai and one An. albimanus collected during fishing activities in canoes were positive for Plasmodium vivax , whereas one female An. neivai collected in a mangrove was positive for P. vivax . In the mangroves and fishing canoes, An. neivai demonstrated biting activity throughout the day, peaking between 06:00 pm-07:00 pm and there were two minor peaks at dusk and dawn. These peaks coincided with fishing activities in the marshlands and mangroves, a situation that places the fishermen at risk of contracting malaria when they are performing their daily activities. It is recommended that protective measures be implemented to reduce the risk that fishermen will contract malaria. PMID:24402159

  6. Assessing the molecular divergence between Anopheles (Kerteszia) cruzii populations from Brazil using the timeless gene: further evidence of a species complex

    PubMed Central

    Rona, Luísa DP; Carvalho-Pinto, Carlos J; Gentile, Carla; Grisard, Edmundo C; Peixoto, Alexandre A

    2009-01-01

    Background Anopheles (Kerteszia) cruzii was the most important vector of human malaria in southern Brazil between 1930–1960. Nowadays it is still considered an important Plasmodium spp. vector in southern and south-eastern Brazil, incriminated for oligosymptomatic malaria. Previous studies based on the analysis of X chromosome banding patterns and inversion frequencies in An. cruzii populations from these areas have suggested the occurrence of three sibling species. In contrast, two genetically distinct groups among An. cruzii populations from south/south-east and north-east Brazil have been revealed by isoenzyme analysis. Therefore, An. cruzii remains unclear. Methods In this study, a partial sequence of the timeless gene (~400 bp), a locus involved in the control of circadian rhythms, was used as a molecular marker to assess the genetic differentiation between An. cruzii populations from six geographically distinct areas of Brazil. Results The timeless gene revealed that An. cruzii from Itaparica Island, Bahia State (north-east Brazil), constitutes a highly differentiated group compared with the other five populations from south and south-east Brazil. In addition, significant genetic differences were also observed among some of the latter populations. Conclusion Analysis of the genetic differentiation in the timeless gene among An. cruzii populations from different areas of Brazil indicated that this malaria vector is a complex of at least two cryptic species. The data also suggest that further work might support the occurrence of other siblings within this complex in Brazil. PMID:19358734

  7. Estimation of divergence time between two sibling species of the Anopheles (Kerteszia) cruzii complex using a multilocus approach

    PubMed Central

    2010-01-01

    Background Anopheles cruzii is the primary human Plasmodium vector in southern and southeastern Brazil. The distribution of this mosquito follows the coast of the Brazilian Atlantic Forest. Previous studies indicated that An. cruzii is a complex of cryptic species. Results A multilocus approach using six loci, three circadian clock genes and three encoding ribosomal proteins, was implemented to investigate in more detail the genetic differentiation between the An. cruzii populations from Santa Catarina (southern Brazil) and Bahia States (northeastern Brazil) that represent two sibling species. The analysis revealed very high FST values and fixed differences between the two An. cruzii sibling species in all loci, irrespective of their function. An Isolation with Migration model was fit to the data using the IM program. The results reveal no migration in either direction and allowed a rough estimate of the divergence time between the two sibling species. Conclusions Population genetics analysis of An. cruzii samples from two Brazilian localities using a multilocus approach confirmed that they represent two different sibling species in this complex. The results suggest that the two species have not exchanged migrants since their separation and that they possibly diverged between 1.1 and 3.6 million years ago, a period of intense climatic changes. PMID:20356389

  8. Anopheles (Kerteszia) cruzii (DIPTERA: CULICIDAE) IN PERIDOMICILIARY AREA DURING ASYMPTOMATIC MALARIA TRANSMISSION IN THE ATLANTIC FOREST: MOLECULAR IDENTIFICATION OF BLOOD-MEAL SOURCES INDICATES HUMANS AS PRIMARY INTERMEDIATE HOSTS

    PubMed Central

    Kirchgatter, Karin; Tubaki, Rosa Maria; Malafronte, Rosely dos Santos; Alves, Isabel Cristina; Lima, Giselle Fernandes Maciel de Castro; Guimarães, Lilian de Oliveira; Zampaulo, Robson de Almeida; Wunderlich, Gerhard

    2014-01-01

    Anopheles (Kerteszia) cruzii has been implicated as the primary vector of human and simian malarias out of the Brazilian Amazon and specifically in the Atlantic Forest regions. The presence of asymptomatic human cases, parasite-positive wild monkeys and the similarity between the parasites infecting them support the discussion whether these infections can be considered as a zoonosis. Although many aspects of the biology of An. cruzii have already been addressed, studies conducted during outbreaks of malaria transmission, aiming at the analysis of blood feeding and infectivity, are missing in the Atlantic Forest. This study was conducted in the location of Palestina, Juquitiba, where annually the majority of autochthonous human cases are notified in the Atlantic Forest of the state of São Paulo. Peridomiciliary sites were selected for collection of mosquitoes in a perimeter of up to 100 m around the residences of human malaria cases. The mosquitoes were analyzed with the purpose of molecular identification of blood-meal sources and to examine the prevalence of Plasmodium. A total of 13,441 females of An. (Ker.) cruzii were collected. The minimum infection rate was calculated at 0.03% and 0.01%, respectively, for P. vivax and P. malariae and only human blood was detected in the blood-fed mosquitoes analyzed. This data reinforce the hypothesis that asymptomatic human carriers are the main source of anopheline infection in the peridomiciliary area, making the probability of zoonotic transmission less likely to happen. PMID:25229220

  9. Kerteszia Theobald (Diptera: Culicidae) mosquitoes and bromeliads: A landscape ecology approach regarding two species in the Atlantic rainforest.

    PubMed

    Chaves, Leonardo Suveges Moreira; Rodrigues de Sá, Ivy Luizi; Bergamaschi, Denise Pimentel; Sallum, Maria Anice Mureb

    2016-12-01

    On the ecological scale of an organism, a homogeneous geographical landscape can represent a mosaic of heterogeneous landscapes. The bionomy of Kerteszia mosquitoes can contribute to foundation landscape ecology by virtue of in the role of the configuration and composition of the habitat played in the distribution of mosquito species. Thus, this study aimed: to compare the abundance of Kerteszia in dense tropical rainforest, restinga and rural area, to assess the bioecological characteristics of the main bromeliads hosting Kerteszia, and to associate the bioecological arrangement of the bromeliads with Kerteszia distribution. Field collections were conducted in a monthly schedule from December of 2010 to November 2011. The vegetation of landscapes was characterized on the basis of a digital cartographic database, the manual of the Brazilian vegetation, environmental atlas information, satellite images and visits to the sites. Multivariate generalized linear models were employed using the R-project statistical program. The results were: Anopheles cruzii was the most frequent species in dense tropical rainforest (67.42%), with a positive association (deviance=25.8; P=0.002). Anopheles bellator was more abundant in the Restinga area (78.97%), with a positive association (deviance=10.4, P=0.018). There was a positive aggregation of Restinga with An. bellator (RR=2.42) but a lower level with An. cruzii (RR=0.31). Thus we can conclude that landscape characteristics influence the distribution of Kerteszia mosquitoes. An. bellator has a higher prevalence in Restinga areas, whereas An. cruzii was the most prevalent in the dense tropical rainforest.

  10. The complete mitochondrial genome of Anopheles minimus (Diptera: Culicidae) and the phylogenetics of known Anopheles mitogenomes.

    PubMed

    Hua, Ya-Qiong; Ding, Yi-Ran; Yan, Zhen-Tian; Si, Feng-Ling; Luo, Qian-Chun; Chen, Bin

    2016-06-01

    Anopheles minimus is an important vector of human malaria in southern China and Southeast Asia. The phylogenetics of mosquitoes has not been well resolved, and the mitochondrial genome (mtgenome) has proven to be an important marker in the study of evolutionary biology. In this study, the complete mtgenome of An. minimus was sequenced for the first time. It is 15 395 bp long and encodes 37 genes, including 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs) and a non-coding region. The gene organization is consistent with those of known Anopheles mtgenomes. The mtgenome performs a clear bias in nucleotide composition with a positive AT-skew and a negative GC-skew. All 13 PCGs prefer to use the codon UUA (Leu), ATN as initiation codon but cytochrome-oxidase subunit 1 (COI) and ND5, with TCG and GTG, and TAA as termination codon, but COI, COII, COIII and ND4, all with the incomplete T. tRNAs have the typical clover-leaf structure, but tRNA(Ser(AGN)) is consistent with known Anopheles mtgenomes. The control region includes a conserved T-stretch and a (TA)n stretch, and has the highest A+T content at 93.1%. The phylogenetics of An. minimus with 18 other Anopheles species was constructed by maximum likelihood and Bayesian inference, based on concatenated PCG sequences. The subgenera, Cellia and Anopheles, and Nyssorhynchus and Kerteszia have mutually close relationships, respectively. The Punctulatus group and Leucosphyrus group of Neomyzomyia Series, and the Albitarsis group of Albitarsis Series were suggested to be monophyletic. The monophyletic status of the subgenera, Cellia, Anopheles, Nyssorhynchus and Kerteszia need to be further elucidated.

  11. Species Composition and Distribution of Adult Anopheles (Diptera: Culicidae) in Panama

    PubMed Central

    LOAIZA, J. R.; BERMINGHAM, E.; SCOTT, M. E.; ROVIRA, J. R.; CONN, J. E.

    2010-01-01

    Anopheles (Diptera: Culicidae) species composition and distribution were studied using human landing catch data over a 35-yr period in Panama. Mosquitoes were collected from 77 sites during 228 field trips carried out by members of the National Malaria Eradication Service. Fourteen Anopheles species were identified. The highest average human biting rates were recorded from Anopheles (Nyssorhynchus) albimanus (Wiedemann) (9.8 bites/person/night) and Anopheles (Anopheles) punctimacula (Dyar and Knab) (6.2 bites/person/night). These two species were also the most common, present in 99.1 and 74.9%, respectively, of the sites. Anopheles (Nyssorhynchus) aquasalis (Curry) was encountered mostly in the indigenous Kuna Yala Comarca along the eastern Atlantic coast, where malaria case history and average human biting rate (9.3 bites/person/night) suggest a local role in malaria transmission. An. albimanus, An. punctimacula, and Anopheles (Anopheles) vestitipennis (Dyar and Knab) were more abundant during the rainy season (May–December), whereas An. aquasalis was more abundant in the dry season (January–April). Other vector species collected in this study were Anopheles (Kerteszia) neivai (Howard, Dyar, and Knab) and Anopheles (Anopheles) pseudopunctipennis s.l. (Theobald). High diversity of Anopheles species and six confirmed malaria vectors in endemic areas of Panama emphasize the need for more detailed studies to better understand malaria transmission dynamics. PMID:18826025

  12. Diversification of the Genus Anopheles and a Neotropical Clade from the Late Cretaceous

    PubMed Central

    Freitas, Lucas A.; Russo, Claudia A. M.; Voloch, Carolina M.; Mutaquiha, Olívio C. F.; Marques, Lucas P.; Schrago, Carlos G.

    2015-01-01

    The Anopheles genus is a member of the Culicidae family and consists of approximately 460 recognized species. The genus is composed of 7 subgenera with diverse geographical distributions. Despite its huge medical importance, a consensus has not been reached on the phylogenetic relationships among Anopheles subgenera. We assembled a comprehensive dataset comprising the COI, COII and 5.8S rRNA genes and used maximum likelihood and Bayesian inference to estimate the phylogeny and divergence times of six out of the seven Anopheles subgenera. Our analysis reveals a monophyletic group composed of the three exclusively Neotropical subgenera, Stethomyia, Kerteszia and Nyssorhynchus, which began to diversify in the Late Cretaceous, at approximately 90 Ma. The inferred age of the last common ancestor of the Anopheles genus was ca. 110 Ma. The monophyly of all Anopheles subgenera was supported, although we failed to recover a significant level of statistical support for the monophyly of the Anopheles genus. The ages of the last common ancestors of the Neotropical clade and the Anopheles and Cellia subgenera were inferred to be at the Late Cretaceous (ca. 90 Ma). Our analysis failed to statistically support the monophyly of the Anopheles genus because of an unresolved polytomy between Bironella and A. squamifemur. PMID:26244561

  13. The Brazilian Malaria Vector Anopheles (Kerteszia) Cruzii: Life Stages and Biology (Diptera: Culicidae)

    DTIC Science & Technology

    1991-11-01

    of the humans in Casa Grande, Sao Paulo State, as well as in many domestic and wild animals . Three other viruses, whose relation to human disease...Publishing, Inc., Marlton, NJ. Comportamento das especies vetoras de Harbach, R.E. and K.L. Knight. 1982. Correc- malaria. Rev. Brasil. Malariol. Doenw

  14. [Anopheles cruzii larvae found in bromelias in an urban area on the Brazilian coast].

    PubMed

    Marques, Gisela R A M; Forattini, Oswaldo Paulo

    2009-04-01

    The occurrence of Anopheles (Kerteszia) cruzii larvae is reported for the first time in bromelias on the ground located in an urban area within the municipality of Ilha Bela, on the northern coast of the State of São Paulo. From March 1998 to July 1999 312 immature forms of An. cruzii were captured, being that 8.6% of them were in bromelias in the urban environment, 40.1% in periurban bromelias and 51.3% in the forest. The average number of bromelias containing An. cruzii was 4.0% of the total investigated. The positive rate in the periurban and forested environments presented similar values. The presence of An. cruzii is probably due to their having been present previously in the forest, together with the frequent presence of these breeding places, food sources and appropriate shelter in the urban area. This set of factors makes it necessary to warn against the possibility of transferring infections from one environment to the other.

  15. Laboratory studies of diel oviposition, fecundity, survival, and gonotrophic cycles in Anopheles homunculus.

    PubMed

    Chadee, D D; Beier, J C; Mohammed, R T

    1998-06-01

    Diel oviposition patterns of Anopheles homunculus were determined from field-collected females in Platanal Forest, Cumaca, Trinidad. The timing and number of eggs oviposited were monitored at 2-h intervals for a set of 30 individual females and a group of 130 females. Individual females of An. homunculus displayed a strongly nocturnal pattern of oviposition. During the 1st gonotrophic cycle, > 65% of ovipositions occurred and > 70% of eggs were laid between 2200 and 0200 h. In the 2nd gonotrophic cycle, 79% of eggs were laid during the same time period. The same trend was found for the 130 females caged together, with > 80% of eggs laid between 2200 and 2400 h. The length of the gonotrophic cycle ranged from 74 to 102 h (mean 81.8 +/- 11.9 h) for the 1st gonotrophic cycle and from 46 to 76 h (mean 56.0 +/- 12.6 h) for the 2nd cycle. The fecundity of An. homunculus averaged 62 eggs in each gonotrophic cycle. No females survived in the laboratory longer than 10 days. These observations on An. homunculus oviposition patterns are the 1st for any species in the subgenus Kerteszia and may be useful for future attempts at colonization.

  16. Habitats and Distribution of Anopheles Sinensis and Associated Anopheles Hyrcanus Group in Japan

    DTIC Science & Technology

    2005-01-01

    SCIENTIFIC NOTE HABITATS AND DISTRffiUTION OF ANOPHELES SINENSIS AND ASSOCIATED ANOPHELES HYRCANUS GROUP IN JAPAN LEOPOLDO M. RUEDA.’ MASASHIRO IWAKAMI.2.b...collections were carried out in August 2002 and July 2003 in Japan . Anopheles sinensis of the Hyrcanus Group. Myzomyia Series of Anopheles. was the...Anopheles sinensis. Hyrcanus Group, Aedes, Clllex, Uranotaenia. Japan . Culicidae The Anopheles Hyrcanus Group consists of sev- eral species that are vectors

  17. Anopheles (Anopheles) pseudopunctipennis Theobald (Diptera: Culicidae): Neotype Designation and Description

    DTIC Science & Technology

    2004-01-01

    1020 (M*, F*, L*); Aitken 1945: 327 (M, F*, P*, L, E*, taxonomy, biology); Vargas and Martinez Palacios 1956: 83 (M*, F*, P*, L*). Anopheles...complex of western America. Univ. Calif. Publ. Entomol. 7: 273Ð364. Alvarado , C. A., and R. L. Heredia. 1947. Observaciones sobre una nueva variedad...Cespedes, R. Vargas -Sagarnaga, and R. Rodriguez. 1992. Evidencia genética de un complejo de especie en Anopheles pseudopunctipennis pseudopunctipennis. Bol

  18. Male motion coordination in swarming Anopheles gambiae and Anopheles coluzzii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Anopheles gambiae species complex comprises the primary vectors of malaria in much of sub-Saharan Africa; most of the mating in these species occurs in swarms composed almost entirely of males. Intermittent, parallel flight patterns in such swarms have been observed, but a detailed description o...

  19. Elevation of Anopheles Chiriquiensis from Synonymy with Anopheles Parapunctipennis and Designation of Name-bearing Types for Anopheles Parapunctipennis and Anopheles Parapunctipennis Guatemalensis (Diptera: Culicidae)

    DTIC Science & Technology

    1989-01-01

    Leon 1938: 4 16, (as An. (Ano.) chiriquiensis var. guatenzalensis) Cumbre de1 Aire, Department of Totonicapan, Guatemala (d*, ?*, L*). Lectotype 9...here designated, bearing the following data: “Sanidad Publica: Guatemala. - A.C.-/Anopheles (Anopheles) A. Chiriquiensis ( ?? Komp)/“ Cumbre de1

  20. Population Structure of the Primary Malaria Vector in South America, Anopheles darlingi, Using Isozyme, Random Amplified Polymorphic DNA, Internal Transcribed Spacer 2, and Morphologic Markers

    DTIC Science & Technology

    1999-01-01

    derscoring some congruence, in this case, between two dif- ferent molecular markers. Intraspecific variation in the ITS2 region of 21 members of...morphism in the salivary gland chromosomes of Anopheles darlingi. Mosq News 32: 555-565. 29. Tadei WP, Santos JMN, Rabbani MG, 1982. Biologia de ano...Contel EPB, dos Santos JMM, Tadei Wp, 1984. Biologia de Anophelinos Amazonicos. VI. Enzimatica em Anopheles dar- lingi Root (Dipt.: Culicidae). Acta

  1. Distribution of Anopheles albimanus, Anopheles vestitipennis, and Anopheles crucians associated with land use in northern Belize.

    PubMed

    Grieco, John P; Johnson, Sarah; Achee, Nicole L; Masuoka, Penny; Pope, Kevin; Rejmánková, Eliska; Vanzie, Errol; Andre, Richard; Roberts, Donald

    2006-05-01

    Anthropogenic land use changes often alter natural patterns of disease transmission. The goal of this study was to determine whether phosphorus input from sugarcane, Saccharum officinarum L., cultivation in northern Belize could pose a significant environmental impact on malaria transmission by changing vegetation structure and composition of wetlands and associated larval habitats. Our primary focus was on the increased dominance of cattail, Typha domingensis Pers., a favored habitat for Anopheles vestitipennis Dyar & Knab. A land cover classification based on satellite imagery was used to select 20 marshes impacted by agricultural runoff and 20 marshes surrounded by forest (nonimpacted). A 100-m transect was established into each of the 40 marshes. Water, vegetation, and larval sampling were conducted at the 0-, 10-, 25-, 50-, and 100-m locations along the transect. Analyses of larval density data indicated that Anopheles albimanus Wiedemann was negatively correlated with percentage of cover of Typha (R2 = 0.39, P < 0.001) but positively correlated with sparse Eleocharis cellulosa Torr. (rush) cover (R2 = 0.19, P < 0.05) and presence of cyanobacterial mats (CBM) (R2 = 0.33, P < 0.0001). An. vestitipennis was found to be positively correlated with percentage of cover of Typha (R2 = 0.19, P < 0.001). Canonical correspondence analysis identified CBM and light as the variables associated with the presence of An. albimanuts larvae, Typha cover with An. vestitipennis larvae, and Eleocharis and absence of light with Anopheles crucians (Wiedemann). A positive correlation also existed between marshes adjacent to agricultural activities and presence of An. vestitipennis (R2 = 0.37, P < 0.05). These results indicate that marshes in proximity to agricultural fields are conducive for Typha growth, thereby providing habitat for the more efficient malaria vector

  2. Adaptation through chromosomal inversions in Anopheles

    PubMed Central

    Ayala, Diego; Ullastres, Anna; González, Josefa

    2014-01-01

    Chromosomal inversions have been repeatedly involved in local adaptation in a large number of animals and plants. The ecological and behavioral plasticity of Anopheles species—human malaria vectors—is mirrored by high amounts of polymorphic inversions. The adaptive significance of chromosomal inversions has been consistently attested by strong and significant correlations between their frequencies and a number of phenotypic traits. Here, we provide an extensive literature review of the different adaptive traits associated with chromosomal inversions in the genus Anopheles. Traits having important consequences for the success of present and future vector control measures, such as insecticide resistance and behavioral changes, are discussed. PMID:24904633

  3. Fine structure of the eggs of Anopheles (Anopheles) apicimacula (Diptera:Culicidae).

    PubMed

    Rodriguez, M H; Chávez, B; Orozco, A; Martínez-Palomo, A

    1996-09-01

    The eggs of Anopheles (Anopheles) apicimacula Dyar and Knab are described from scanning electron micrographs. The eggs are boat-shaped, with frills that extend ventrally along the length of the egg and surround the deck region. The ornamentation on the dorsal and lateral surfaces is formed by groups of smooth, round tubercles. The ventral surface is covered by irregularly jagged tubercles. Prominent lobed tubercles are present at the anterior and posterior ends of the deck.

  4. Abundance patterns of Anopheles pseudopunctipennis and Anopheles argyritarsis in northwestern Argentina.

    PubMed

    Dantur Juri, María Julia; Claps, Guillermo Luis; Santana, Mirta; Zaidenberg, Mario; Almirón, Walter Ricardo

    2010-09-01

    Anopheles pseudopunctipennis is an important malaria vector in Argentina but the role of Anopheles argyritarsis in the transmission of the parasite is still unknown. Abundance patterns of both species and their relationship to climatic variables were studied in the subtropical mountainous forest in northwestern Argentina. Adults were collected with CDC light traps from September 2002 to November 2005 in Salta (northern area) and Tucumán (southern area) provinces, from 3 localities in each province. The abundance of both species in localities was compared using the Kruskal-Wallis test, and their changes in abundance in relation to climatic variables were analyzed by Multilevel Poisson Regression. Anopheles argyritarsis was more abundant than A. pseudopunctipennis, and both reached a peak during the spring. There were significant differences in abundance in the northern localities for A. pseudopunctipennis, and between northern and southern localities for A. argyritarsis. Temperature, rainfall and relative humidity were significant predictors of the abundance of these two species.

  5. Anopheles (Anopheles) Lesteri Biases and Hu (Diptera: Culicidae): Neotype Designation and Description

    DTIC Science & Technology

    2005-06-30

    Anopheles) anthropoplwglts: Ma 1981: 1I (key; distribution, China: Fukien. Kiangsi. Kiangsu. Kwangsi. Kweichow. Shanghai. provinces south of Yantze River ...lowing: Taina Litwak for her illustrations; Bel Rueda, Buddy Buenavista. Lerma Bue- navista. Benjie Puma. and Modesta Coro- nado-Puma for their help in

  6. First Record of Anopheles oryzalimnetes, Anopheles argyritarsis, and Anopheles sawyeri (Diptera: Culicidae) in the Caatinga Biome, Semiarid Scrubland of Sergipe State, Brazil.

    PubMed

    Marteis, L S; Sallum, M A M; Natal, D; Oliveira, T M P; Gama, R A; Dolabella, S S; Santos, R L C

    2015-09-01

    Caatinga is one of the least known biomes of Brazil in relation to biodiversity. The dry condition of semiarid areas has been associated in the past with low richness of fauna and flora, not encouraging studies in this region. There is a lack of mosquito records including anophelines. Thus, to investigate the biodiversity of Anopheles mosquitoes in the Caatinga biome, we collected immature mosquitoes in aquatic habitats in a conservation reserve located in the northwestern portion of Sergipe state. The captured specimens were initially identified as Anopheles albitarsis l.s. and Anopheles argyritarsis l.s. To confirm the morphological identification, sequences were generated by cytochrome oxidase subunit I mitocondrial gene. The results showed that the specimens belong to the species Anopheles oryzalimnetes, An. argyritarsis, and Anopheles sawyeri. These are the first records of these species in this region. The presence of Anopheles in the Caatinga biome, which is characterized by arid and semiarid climatic conditions, encourages the interest in the study of biological, physiological, and behavioral adaptations, selected over time, which allow these mosquito populations to survive through the long periods of drought that is characteristic of this region.

  7. Neuropeptides and Peptide Hormones in Anopheles gambiae

    NASA Astrophysics Data System (ADS)

    Riehle, Michael A.; Garczynski, Stephen F.; Crim, Joe W.; Hill, Catherine A.; Brown, Mark R.

    2002-10-01

    The African malaria mosquito, Anopheles gambiae, is specialized for rapid completion of development and reproduction. A vertebrate blood meal is required for egg production, and multiple feedings subsequently allow transmission of malaria parasites, Plasmodium spp. Regulatory peptides from 35 genes annotated from the A. gambiae genome likely coordinate these and other physiological processes. Plasmodium parasites may affect actions of newly identified insulin-like peptides, which coordinate growth and reproduction of its vector, A. gambiae, as in Drosophila melanogaster, Caenorhabditis elegans, and mammals. This genomic information provides a basis to expand understanding of hematophagy and pathogen transmission in this mosquito.

  8. Vector competence of Anopheles and Culex mosquitoes for Zika virus.

    PubMed

    Dodson, Brittany L; Rasgon, Jason L

    2017-01-01

    Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. Although Aedes mosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, including Culex and Anopheles species, and we lack a thorough understanding of which mosquito species to target for vector control. We exposed Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint, Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes were refractory to Zika virus infection. We conclude that Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus.

  9. Vector competence of Anopheles and Culex mosquitoes for Zika virus

    PubMed Central

    Dodson, Brittany L.

    2017-01-01

    Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. Although Aedes mosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, including Culex and Anopheles species, and we lack a thorough understanding of which mosquito species to target for vector control. We exposed Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint, Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes were refractory to Zika virus infection. We conclude that Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus. PMID:28316896

  10. A New Classification for the Leucosphyrus Group of Anopheles (Cellia)

    DTIC Science & Technology

    1989-01-01

    some modification in Knight and Marks (1952) for the subgenus Finlaya of Aedes and were standardized for the genus Anopheles, subgenus Anopheles by...Zool. 32: 321-329. Knight, K.L. and E.N. Marks. 1952. An annotated checklist of the mosquitoes of the subgenus Finlaya, genus Aedes . Proc. U.S. Nat... Mosquito Systematics Vol. 21(3) 1989 197 A New Classification for the Leucosphyrus Group of Anopheles (Cellia)’ E.L. Peyton”*” ABSTRACT. The

  11. Distinct population structure for co-occurring Anopheles goeldii and Anopheles triannulatus in Amazonian Brazil

    PubMed Central

    McKeon, Sascha Naomi; Moreno, Marta; Sallum, Maria Anise; Povoa, Marinete Marins; Conn, Jan Evelyn

    2013-01-01

    To evaluate whether environmental heterogeneity contributes to the genetic heterogeneity in Anopheles triannulatus, larval habitat characteristics across the Brazilian states of Roraima and Pará and genetic sequences were examined. A comparison with Anopheles goeldii was utilised to determine whether high genetic diversity was unique to An. triannulatus. Student t test and analysis of variance found no differences in habitat characteristics between the species. Analysis of population structure of An. triannulatus and An. goeldii revealed distinct demographic histories in a largely overlapping geographic range. Cytochrome oxidase I sequence parsimony networks found geographic clustering for both species; however nuclear marker networks depicted An. triannulatus with a more complex history of fragmentation, secondary contact and recent divergence. Evidence of Pleistocene expansions suggests both species are more likely to be genetically structured by geographic and ecological barriers than demography. We hypothesise that niche partitioning is a driving force for diversity, particularly in An. triannulatus. PMID:23903977

  12. Odorant reception in the malaria mosquito Anopheles gambiae.

    PubMed

    Carey, Allison F; Wang, Guirong; Su, Chih-Ying; Zwiebel, Laurence J; Carlson, John R

    2010-03-04

    The mosquito Anopheles gambiae is the major vector of malaria in sub-Saharan Africa. It locates its human hosts primarily through olfaction, but little is known about the molecular basis of this process. Here we functionally characterize the Anopheles gambiae odorant receptor (AgOr) repertoire. We identify receptors that respond strongly to components of human odour and that may act in the process of human recognition. Some of these receptors are narrowly tuned, and some salient odorants elicit strong responses from only one or a few receptors, suggesting a central role for specific transmission channels in human host-seeking behaviour. This analysis of the Anopheles gambiae receptors permits a comparison with the corresponding Drosophila melanogaster odorant receptor repertoire. We find that odorants are differentially encoded by the two species in ways consistent with their ecological needs. Our analysis of the Anopheles gambiae repertoire identifies receptors that may be useful targets for controlling the transmission of malaria.

  13. Blood-feeding behavior of Anopheles gambiae and Anopheles melas in Ghana, western Africa.

    PubMed

    Tuno, Nobuko; Kjaerandsen, Jostein; Badu, Kingsley; Kruppa, Thomas

    2010-01-01

    Anopheles gambiae is the predominant malaria vector species in Ghana, western Africa, with a strong local presence of Anopheles melas Theobald along the southern coast. We studied the biting behavior of these two species of the Anopheles gambiae complex inland and at the coast in Ghana, with special attention to the local peoples' preference for outdoor sleeping. We collected mosquitoes at two sites in 2007, representing the moist semideciduous forest zone and the strand and mangrove zone, and the sampling was repeated in the dry and rainy seasons. Sampled mosquitoes were examined for species, parity and size (wing length), and we identified the hosts of their bloodmeals. We interviewed 288 of the village people to determine where and when they slept outdoors. Our study confirmed that An. gambiae is the only species of the An. gambiae complex in the Ashanti region and revealed that An. melas is highly dominant on the western coast of Ghana. Both species showed high human blood rates in indoor resting mosquito samples. More people sleep outside on the coast than inland. An. melas demonstrated high exophily. An. gambiae bit people more frequently indoors and did so more often during the dry season than in the rainy season. We suggest that the degree of exophily in An. melas may be affected by humidity and the availability of human as well as by the mosquitoes' innate habits.

  14. The mosquito Anopheles (Cellia) oreios sp. n., formerly species 6 of the Australasian Anopheles farauti complex, and a critical review of its biology and relation to disease.

    PubMed

    Bangs, M J; Taai, K; Howard, T M; Cook, S; Harbach, R E

    2015-03-01

    Species 6 of the Australasian Anopheles farauti sibling species complex (Diptera: Culicidae) is described and formally named Anopheles oreios Bangs & Harbach, sp. n. Adult, pupal and fourth-instar larval specimens collected in the Baliem Valley, Papua Province, Indonesia, are characterized and compared with those of Anopheles farauti, Anopheles hinesorum, Anopheles irenicus and Anopheles torresiensis (formerly informally denoted as species 1, 2, 7 and 3, respectively). The variable wings of adult females, the male genitalia, the pupa and the fourth-instar larva of An. oreios are illustrated and DNA sequence data are included for regions coding for sections of the mitochondrial COI and COII genes. The biology of An. oreios and its relation to malaria transmission are discussed in detail and contrasted with the biology and disease relations of some members of the An. farauti and Anopheles punctulatus sibling species complexes.

  15. Colonization of Anopheles pseudopunctipennis from Mexico.

    PubMed

    Villarreal, C; Arredondo-Jiménez, J I; Rodriguez, M H; Ulloa, A

    1998-12-01

    Two colonies of Anopheles pseudopunctipennis, Tapachula and Abasolo strains, were established under laboratory conditions with a thermoperiod (29 degrees C during the day; 24 degrees C during the night) and artificial dusk. To stimulate mating, a light beam from a flashlight was shone on the cage shortly after lights off. This procedure was repeated for the first 6 mosquito generations (parental to F6) and thereafter light stimulation was unnecessary for mating. The Tapachula colony has been maintained for 24 generations in 24 months, with insemination rates in females > 80% since the F3, and a monthly production of 30,000 pupae since the F7. Using the same procedure, the Abasolo colony from northeastern Mexico has been maintained for 13 generations in 14 months, with insemination rates of 26-52%.

  16. Ecological Suitability and Spatial Distribution of Five Anopheles Species in Amazonian Brazil

    PubMed Central

    McKeon, Sascha N.; Schlichting, Carl D.; Povoa, Marinete M.; Conn, Jan E.

    2013-01-01

    Seventy-six sites characterized in Amazonian Brazil revealed distinct habitat diversification by examining the environmental factors associated with the distribution and abundance of five anopheline species (Diptera: Culicidae) in the subgenus Nyssorhynchus. These included three members of the Albitarsis Complex, Anopheles oryzalimnetes, Anopheles marajoara, Anopheles janconnae; Anopheles triannulatus, and Anopheles goeldii. Anopheles janconnae abundance had a positive correlation to water flow and a negative relationship to sun exposure. Abundance of An. oryzalimentes was associated with water chemistry. Anopheles goeldii larvae were abundant in shaded, more saline waters. Anopheles marajoara and An. triannulatus were negatively associated with available resources, although An. marajoara also showed several local correlations. These analyses suggest An. triannulatus is a habitat generalist, An. oryzalimentes and An. janconnae are specialists, and An. marajoara and An. goeldii could not be easily classified either way. Correlations described herein provide testable hypotheses for future research and identifying habitats for vector control. PMID:23546804

  17. Comparison of transmission parameters between Anopheles argyritarsis and Anopheles pseudopunctipennis in two ecologically different localities of Bolivia

    PubMed Central

    2013-01-01

    Background Anopheles (Anopheles) pseudopunctipennis is a recognized malaria vector in the slopes of the Andes of Bolivia. There, other species might be involved in malaria transmission and one candidate could be Anopheles argyritarsis. Although it is generally admitted that this species is not a malaria vector in the neotropical region, its potential role in transmission is still controversial and this situation has to be cleared, at least for Bolivia. Comparing the vectorial efficiency of An. pseudopunctipennis with that of An. argyritarsis could solve the question. Methods The two species were sampled throughout Bolivia to estimate their degree of co-existence in their distribution range. Vectorial efficiencies of the two species were compared in two ecologically different localities where the species were sympatric by analysing their vectorial capacities and components (i e, human biting rates, human biting index, survival, durations of the gonotrophic cycle and extrinsic cycle), and the entomological inoculation rates (EIR). Mosquitoes were sampled monthly during more than one year in the two localities. A monthly sample consisted in hourly captures in four houses (inside and outside) in each locality, during four consecutive nights. Climatic variables (temperature, humidity, potential evapo-transpiration and precipitations) were recorded to better understand variability in the entomological parameters. Relationships were analysed using multivariate methods. Results Anopheles pseudopunctipennis and An. argyritarsis are “altitude” species, sharing the same geographical distribution range in the Andes of Bolivia. No Plasmodium parasite was identified in An. argyritarsis and estimates of the vectorial capacity indicated that it is not a malaria vector in the two studied localities, unlike An. pseudopunctipennis which showed positive EIRs. This latter species, although not a very good malaria vector, exhibited better life traits values and better behavioural

  18. Mark-recapture studies of host selection by Anopheles (Anopheles) vestitipennis.

    PubMed

    Ulloa, Armando; Arredondo-Jiménez, Juan I; Rodriguez, Mario H; Fernández-Salas, Ildefonso

    2002-03-01

    We present herein the results of a series of mark-recapture experiments with female Anopheles vestitipennis. Theses experiments used human and animal hosts to assess the degree of anthropophily of field-caught specimens, originally collected on either host, and of their offspring. Fidelity of mosquitoes to particular hosts was estimated by recapturing marked host-seeking mosquitoes returning for a 2nd blood meal. Results indicated that mosquitoes seeking animal hosts were more faithful (80.48%; 33 of 41) in returning to their original host than were those seeking human hosts (63%; 49 of 78).

  19. Factors affecting fungus-induced larval mortality in Anopheles gambiae and Anopheles stephensi

    PubMed Central

    2010-01-01

    Background Entomopathogenic fungi have shown great potential for the control of adult malaria vectors. However, their ability to control aquatic stages of anopheline vectors remains largely unexplored. Therefore, how larval characteristics (Anopheles species, age and larval density), fungus (species and concentration) and environmental effects (exposure duration and food availability) influence larval mortality caused by fungus, was studied. Methods Laboratory bioassays were performed on the larval stages of Anopheles gambiae and Anopheles stephensi with spores of two fungus species, Metarhizium anisopliae and Beauveria bassiana. For various larval and fungal characteristics and environmental effects the time to death was determined and survival curves established. These curves were compared by Kaplan Meier and Cox regression analyses. Results Beauveria bassiana and Metarhizium anisopliae caused high mortality of An. gambiae and An. stephensi larvae. However, Beauveria bassiana was less effective (Hazard ratio (HR) <1) compared to Metarhizium anisopliae. Anopheles stephensi and An. gambiae were equally susceptible to each fungus. Older larvae were less likely to die than young larvae (HR < 1). The effect of increase in fungus concentration on larval mortality was influenced by spore clumping. One day exposure to fungal spores was found to be equally effective as seven days exposure. In different exposure time treatments 0 - 4.9% of the total larvae, exposed to fungus, showed infection at either the pupal or adult stage. Mortality rate increased with increasing larval density and amount of available food. Conclusions This study shows that both fungus species have potential to kill mosquitoes in the larval stage, and that mortality rate depends on fungus species itself, larval stage targeted, larval density and amount of nutrients available to the larvae. Increasing the concentration of fungal spores or reducing the exposure time to spores did not show a proportional

  20. Functional characterisation of the Anopheles leucokinins and their cognate G-protein coupled receptor.

    PubMed

    Radford, Jonathan C; Terhzaz, Selim; Cabrero, Pablo; Davies, Shireen-A; Dow, Julian A T

    2004-12-01

    Identification of the Anopheles gambiae leucokinin gene from the completed A. gambiae genome revealed that this insect species contains three leucokinin peptides, named Anopheles leucokinin I-III. These peptides are similar to those identified in two other mosquito species, Aedes aegypti and Culex salinarius. Additionally, Anopheles leucokinin I displays sequence similarity to Drosophila melanogaster leucokinin. Using a combination of computational and molecular approaches, a full-length cDNA for a candidate leucokinin-like receptor was isolated from A. stephensi, a close relative of A. gambiae. Alignment of the known leucokinin receptors--all G protein-coupled receptors (GPCRs)--with this receptor, identified some key conserved regions within the receptors, notably transmembrane (TM) domains I, II, III, VI and VII. The Anopheles leucokinins and receptor were shown to be a functional receptor-ligand pair. All three Anopheles leucokinins caused a dose-dependent rise in intracellular calcium ([Ca2+]i) when applied to S2 cells co-expressing the receptor and an aequorin transgene, with a potency order of I>II>III. Drosophila leucokinin was also found to activate the Anopheles receptor with a similar EC50 value to Anopheles leucokinin I. However, when the Anopheles peptides were applied to the Drosophila receptor, only Anopheles leucokinin I and II elicited a rise in [Ca2+]i. This suggests that the Anopheles receptor has a broader specificity for leucokinin ligands than the Drosophila receptor. Antisera raised against the Anopheles receptor identified a doublet of approx. 65 and 72 kDa on western blots, consistent with the presence of four N-glycosylation sites within the receptor sequence, and the known glycosylation of the receptor in Drosophila. In Anopheles tubules, as in Drosophila, the receptor was localised to the stellate cells. Thus we provide the first identification of Anopheles mosquito leucokinins (Anopheles leucokinins) and a cognate leucokinin receptor

  1. Composition of Anopheles coluzzii and Anopheles gambiae microbiota from larval to adult stages.

    PubMed

    Gimonneau, Geoffrey; Tchioffo, Majoline T; Abate, Luc; Boissière, Anne; Awono-Ambéné, Parfait H; Nsango, Sandrine E; Christen, Richard; Morlais, Isabelle

    2014-12-01

    During their immature life stages, malaria mosquitoes are exposed to a wide array of microbes and contaminants from the aquatic habitats. Although prior studies have suggested that environmental exposure shapes the microbial community structure in the adult mosquito, most reports have focused on laboratory-based experiments and on a single mosquito epithelium, the gut. In this study, we investigated the influence of the breeding site on the development of the Anopheles coluzzii and Anopheles gambiae microbiota in natural conditions. We characterized bacterial communities from aquatic habitats, at surface microlayer and subsurface water levels, to freshly emerge adult mosquitoes using multiplexed 16S rRNA gene pyrosequencing and we separately analyzed the microbiota associated with the different epithelia of adult individual, midguts, ovaries and salivary glands. We found that the distribution of bacterial communities in the aquatic habitats differed according to the depth of water collections. Inter-individual variation of bacterial composition was large in larvae guts but adult mosquitoes from a same breeding site shared quite similar microbiota. Although some differences in bacterial abundances were highlighted between the different epithelia of freshly emerged An. coluzzii and An. gambiae, an intriguing feature from our study is the particular similarity of the overall bacterial communities. Our results call for further investigations on the bacterial population dynamics in the different tissues to determine the distinctive characteristics of each microbiota during the mosquito lifespan and to identify specific interactions between certain key phyla or species and the insect life history traits.

  2. Laser induced mortality of Anopheles stephensi mosquitoes

    PubMed Central

    Keller, Matthew D.; Leahy, David J.; Norton, Bryan J.; Johanson, Threeric; Mullen, Emma R.; Marvit, Maclen; Makagon, Arty

    2016-01-01

    Small, flying insects continue to pose great risks to both human health and agricultural production throughout the world, so there remains a compelling need to develop new vector and pest control approaches. Here, we examined the use of short (<25 ms) laser pulses to kill or disable anesthetized female Anopheles stephensi mosquitoes, which were chosen as a representative species. The mortality of mosquitoes exposed to laser pulses of various wavelength, power, pulse duration, and spot size combinations was assessed 24 hours after exposure. For otherwise comparable conditions, green and far-infrared wavelengths were found to be more effective than near- and mid-infrared wavelengths. Pulses with larger laser spot sizes required lower lethal energy densities, or fluence, but more pulse energy than for smaller spot sizes with greater fluence. Pulse duration had to be reduced by several orders of magnitude to significantly lower the lethal pulse energy or fluence required. These results identified the most promising candidates for the lethal laser component in a system being designed to identify, track, and shoot down flying insects in the wild. PMID:26887786

  3. Metabolic Pathways in Anopheles stephensi mitochondria

    PubMed Central

    Giulivi, Cecilia; Ross-Inta, Catherine; Horton, Ashley A.; Luckhart, Shirley

    2017-01-01

    No studies have been performed on mitochondria of malaria vector mosquitoes. This information would be valuable in understanding mosquito aging and detoxification of insecticides, two parameters that significantly impact malaria parasite transmission in endemic regions. Here, we report the analyses of respiration and oxidative phosphorylation in mitochondria of cultured cells (ASE line) from Anopheles stephensi, a major vector of malaria in India, Southeast Asia and parts of the Middle East. ASE cell mitochondria shared many features in common with mammalian muscle mitochondria, despite the fact that these cells have a larval origin. However, two major differences with mammalian mitochondria were apparent. One, the glycerol-phosphate shuttle plays a major role in NADH oxidation in ASE cell mitochondria as it does in insect muscle mitochondria. In contrast, mammalian white muscle mitochondria depend primarily on lactate dehydrogenase, whereas red muscle mitochondria depend on the malate-oxaloacetate shuttle. Two, ASE mitochondria were able to oxidize Pro at a rate comparable with that of α-glycerophosphate. However, the Pro pathway appeared to differ from the currently accepted pathway, in that ketoglutarate could be catabolyzed completely by the Krebs cycle or via transamination depending on the ATP need. PMID:18588503

  4. Laser induced mortality of Anopheles stephensi mosquitoes

    NASA Astrophysics Data System (ADS)

    Keller, Matthew D.; Leahy, David J.; Norton, Bryan J.; Johanson, Threeric; Mullen, Emma R.; Marvit, Maclen; Makagon, Arty

    2016-02-01

    Small, flying insects continue to pose great risks to both human health and agricultural production throughout the world, so there remains a compelling need to develop new vector and pest control approaches. Here, we examined the use of short (<25 ms) laser pulses to kill or disable anesthetized female Anopheles stephensi mosquitoes, which were chosen as a representative species. The mortality of mosquitoes exposed to laser pulses of various wavelength, power, pulse duration, and spot size combinations was assessed 24 hours after exposure. For otherwise comparable conditions, green and far-infrared wavelengths were found to be more effective than near- and mid-infrared wavelengths. Pulses with larger laser spot sizes required lower lethal energy densities, or fluence, but more pulse energy than for smaller spot sizes with greater fluence. Pulse duration had to be reduced by several orders of magnitude to significantly lower the lethal pulse energy or fluence required. These results identified the most promising candidates for the lethal laser component in a system being designed to identify, track, and shoot down flying insects in the wild.

  5. RNAi Trigger Delivery into Anopheles gambiae Pupae.

    PubMed

    Regna, Kimberly; Harrison, Rachel M; Heyse, Shannon A; Chiles, Thomas C; Michel, Kristin; Muskavitch, Marc A T

    2016-03-08

    RNA interference (RNAi), a naturally occurring phenomenon in eukaryotic organisms, is an extremely valuable tool that can be utilized in the laboratory for functional genomic studies. The ability to knockdown individual genes selectively via this reverse genetic technique has allowed many researchers to rapidly uncover the biological roles of numerous genes within many organisms, by evaluation of loss-of-function phenotypes. In the major human malaria vector Anopheles gambiae, the predominant method used to reduce the function of targeted genes involves injection of double-stranded (dsRNA) into the hemocoel of the adult mosquito. While this method has been successful, gene knockdown in adults excludes the functional assessment of genes that are expressed and potentially play roles during pre-adult stages, as well as genes that are expressed in limited numbers of cells in adult mosquitoes. We describe a method for the injection of Serine Protease Inhibitor 2 (SRPN2) dsRNA during the early pupal stage and validate SRPN2 protein knockdown by observing decreased target protein levels and the formation of melanotic pseudo-tumors in SRPN2 knockdown adult mosquitoes. This evident phenotype has been described previously for adult stage knockdown of SRPN2 function, and we have recapitulated this adult phenotype by SRPN2 knockdown initiated during pupal development. When used in conjunction with a dye-labeled dsRNA solution, this technique enables easy visualization by simple light microscopy of injection quality and distribution of dsRNA in the hemocoel.

  6. Behavioral Cost & Overdominance in Anopheles gambiae

    PubMed Central

    Diop, Malal M.; Moiroux, Nicolas; Chandre, Fabrice; Martin-Herrou, Hadrien; Milesi, Pascal; Boussari, Olayidé; Porciani, Angélique; Duchon, Stéphane; Labbé, Pierrick; Pennetier, Cédric

    2015-01-01

    In response to the widespread use of control strategies such as Insecticide Treated Nets (ITN), Anopheles mosquitoes have evolved various resistance mechanisms. Kdr is a mutation that provides physiological resistance to the pyrethroid insecticides family (PYR). In the present study, we investigated the effect of the Kdr mutation on the ability of female An. gambiae to locate and penetrate a 1cm-diameter hole in a piece of netting, either treated with insecticide or untreated, to reach a bait in a wind tunnel. Kdr homozygous, PYR-resistant mosquitoes were the least efficient at penetrating an untreated damaged net, with about 51% [39-63] success rate compared to 80% [70-90] and 78% [65-91] for homozygous susceptible and heterozygous respectively. This reduced efficiency, likely due to reduced host-seeking activity, as revealed by mosquito video-tracking, is evidence of a recessive behavioral cost of the mutation. Kdr heterozygous mosquitoes were the most efficient at penetrating nets treated with PYR insecticide, thus providing evidence for overdominance, the rarely-described case of heterozygote advantage conveyed by a single locus. The study also highlights the remarkable capacity of female mosquitoes, whether PYR-resistant or not, to locate holes in bed-nets. PMID:25831058

  7. Anopheles Midgut FREP1 Mediates Plasmodium Invasion*

    PubMed Central

    Zhang, Genwei; Niu, Guodong; Franca, Caio M.; Dong, Yuemei; Wang, Xiaohong; Butler, Noah S.; Dimopoulos, George; Li, Jun

    2015-01-01

    Malaria transmission depends on sexual stage Plasmodium parasites successfully invading Anopheline mosquito midguts following a blood meal. However, the molecular mechanisms of Plasmodium invasion of mosquito midguts have not been fully elucidated. Previously, we showed that genetic polymorphisms in the fibrinogen-related protein 1 (FREP1) gene are significantly associated with Plasmodium falciparum infection in Anopheles gambiae, and FREP1 is important for Plasmodium berghei infection of mosquitoes. Here we identify that the FREP1 protein is secreted from the mosquito midgut epithelium and integrated as tetramers into the peritrophic matrix, a chitinous matrix formed inside the midgut lumen after a blood meal feeding. Moreover, we show that the FREP1 can directly bind Plasmodia sexual stage gametocytes and ookinetes. Notably, ablating FREP1 expression or targeting FREP1 with antibodies significantly decreases P. falciparum infection in mosquito midguts. Our data support that the mosquito-expressed FREP1 mediates mosquito midgut invasion by multiple species of Plasmodium parasites via anchoring ookinetes to the peritrophic matrix and enabling parasites to penetrate the peritrophic matrix and the epithelium. Thus, targeting FREP1 can limit malaria transmission. PMID:25991725

  8. Bionomics of Anopheles spp. (Diptera: Culicidae) in a malaria endemic region of Sukabumi, West Java, Indonesia.

    PubMed

    Stoops, Craig A; Rusmiarto, Saptoro; Susapto, Dwiko; Munif, Amurl; Andris, Heri; Barbara, Kathryn A; Sukowati, Supratman

    2009-12-01

    A 15-month bionomic study of Anopheles species was conducted in two ecologically distinct villages (coastal and upland) of Sukabumi District, West Java, Indonesia from June 2006 to September 2007. Mosquitoes were captured using human-landing collections at both sites. During the study, a total of 17,100 Anopheles mosquitoes comprising 13 Anopheles species were caught: 9,151 at the coastal site and 7,949 at the upland site. Anopheles barbirostris, Anopheles maculatus, and Anopheles vagus were the predominant species caught at the coastal site, and Anopheles aconitus, Anopheles barbirostris, and An. maculatus predominated in the upland site. Overall, species were exophagic at both sites, but there was variation between species. Anopheles aconitus was endophagic at the coastal site, exophagic at the upland site, collected most often in April 2007 and had a peak landing time between 22:00 and 23:00. Anopheles sundaicus was only collected at the coastal site, exophagic, collected most often in October 2006, and had a peak landing time between 19:00 and 20:00. Potential malaria vector species such An. aconitus, An. maculatus, and An. sundaicus were present throughout the year. None of the 7,770 Anopheles tested using CSP-ELISA were positive for malaria, although the risk for malaria outbreaks in Sukabumi district remains high.

  9. Mermithid nematodes found in adult Anopheles from southeastern Senegal

    PubMed Central

    2012-01-01

    Background Over two dozen mermithid nematodes have been described parasitizing mosquitoes worldwide, however, only two species were found in Africa. Mermithid nematodes kill their mosquito host upon emergence, which suggests that they could be developed as biological control agents of mosquitoes. Both Romanomermis culicivorax and Romanomermis iyengari have been reared for mass release to control numerous Anopheles species vector populations, and in one instance this may have led to reduced malaria prevalence in a human population. Methods Anopheles mosquitoes were collected during a malaria study in southeastern Senegal. Two different adult blood fed mosquitoes had a single mermithid nematode emerge from their anus while they were being held post-capture. Primers from the 18 S rDNA were developed to sequence nematode DNA and screen mosquitoes for mermithid DNA. 18 S rDNA from the Senegalese mermithid and other mermithid entries in GenBank were used to create a Maximum Parsimony tree of the Mermithidae family. Results The mermithid was present in 1.8% (10/551) of the sampled adult Anopheles species in our study area. The mermithid was found in An. gambiae s.s., An. funestus, and An. rufipes from the villages of Ndebou, Boundoucondi, and Damboucoye. Maximum parsimony analysis confirmed that the nematode parasites found in Anopheles were indeed mermithid parasites, and of the mermithid sequences available in GenBank, they are most closely related to Strelkovimermis spiculatus. Conclusions To our knowledge, this is the first report of mermithids from adult Anopheles mosquitoes in Senegal. The mermithid appears to infect Anopheles mosquitoes that develop in diverse larval habitats. Although maximum parsimony analysis determined the mermithid was closely related to Strelkovimermis spiculatus, several characteristics of the mermithid were more similar to the Empidomermis genus. Future mermithid isolations will hopefully allow: formal taxonomic identification

  10. Biology & control of Anopheles culicifacies Giles 1901

    PubMed Central

    Sharma, V.P.; Dev, V.

    2015-01-01

    Malaria epidemiology is complex due to multiplicity of disease vectors, sibling species complex and variations in bionomical characteristics, vast varied terrain, various ecological determinants. There are six major mosquito vector taxa in India, viz. Anopheles culicifacies, An. fluviatilis, An. stephensi, An. minimus, An. dirus and An. sundaicus. Among these, An. culicifacies is widely distributed and considered the most important vector throughout the plains and forests of India for generating bulk of malaria cases (>60% annually). Major malaria epidemics are caused by An. culicifaices. It is also the vector of tribal malaria except parts of Odisha and Northeastern States of India. An. culicifacies has been the cause of perennial malaria transmission in forests, and over the years penetrated the deforested areas of Northeast. An. culicifacies participates in malaria transmission either alone or along with An. stephensi or An. fluviatilis. The National Vector Borne Disease Control Programme (NVBDCP) spends about 80 per cent malaria control budget annually in the control of An. culicifacies, yet it remains one of the most formidable challenges in India. With recent advances in molecular biology there has been a significant added knowledge in understanding the biology, ecology, genetics and response to interventions, requiring stratification for cost-effective and sustainable malaria control. Research leading to newer interventions that are evidence-based, community oriented and sustainable would be useful in tackling the emerging challenges in malaria control. Current priority areas of research should include in-depth vector biology and control in problem pockets, preparation of malaria-risk maps for focused and selective interventions, monitoring insecticide resistance, cross-border initiative and data sharing, and coordinated control efforts for achieving transmission reduction, and control of drug-resistant malaria. The present review on An. culicifacies

  11. Anthropophilic Anopheles species composition and malaria in Tierradentro, Córdoba, Colombia

    PubMed Central

    Schiemann, David Joachim; Pinzón, Martha Lucía Quiñones; Hankeln, Thomas

    2014-01-01

    Malaria is still a primary health problem in Colombia. The locality of Tierradentro is situated in the municipality of Montelíbano, Córdoba, in the northwest of Colombia, and has one of the highest annual parasite index of malaria nationwide. However, the vectors involved in malaria transmission in this locality have not yet been identified. In this study, the local anthropophilic Anopheles composition and natural infectivity with Plasmodium were investigated. In August 2009, 927 female Anopheles mosquitoes were collected in eight localities using the human landing catch method and identified based on their morphology. Cryptic species were determined by restriction fragment length polymorphism-internal transcribed spacer (ITS)2 molecular analysis. Eight species [Anopheles nuneztovari s.l. (92.8%), Anopheles darlingi (5.1%), Anopheles triannulatus s.l. (1.8%), Anopheles pseudopunctipennis s.l. (0.2%), Anopheles punctimacula s.l. (0.2%), Anopheles apicimacula (0.1%), Anopheles albimanus (0.1%) and Anopheles rangeli (0.1%)] were identified and species identity was confirmed by ITS2 sequencing. This is the first report of An. albimanus, An. rangeli and An. apicimacula in Tierradentro. Natural infectivity with Plasmodium was determined by ELISA. None of the mosquitoes was infectious for Plasmodium. An. nuneztovari s.l. was the predominant species and is considered the primary malaria vector; An. darlingi and An. triannulatus s.l. could serve as secondary vectors.

  12. The genome of Anopheles darlingi, the main neotropical malaria vector.

    PubMed

    Marinotti, Osvaldo; Cerqueira, Gustavo C; de Almeida, Luiz Gonzaga Paula; Ferro, Maria Inês Tiraboschi; Loreto, Elgion Lucio da Silva; Zaha, Arnaldo; Teixeira, Santuza M R; Wespiser, Adam R; Almeida E Silva, Alexandre; Schlindwein, Aline Daiane; Pacheco, Ana Carolina Landim; Silva, Artur Luiz da Costa da; Graveley, Brenton R; Walenz, Brian P; Lima, Bruna de Araujo; Ribeiro, Carlos Alexandre Gomes; Nunes-Silva, Carlos Gustavo; de Carvalho, Carlos Roberto; Soares, Célia Maria de Almeida; de Menezes, Claudia Beatriz Afonso; Matiolli, Cleverson; Caffrey, Daniel; Araújo, Demetrius Antonio M; de Oliveira, Diana Magalhães; Golenbock, Douglas; Grisard, Edmundo Carlos; Fantinatti-Garboggini, Fabiana; de Carvalho, Fabíola Marques; Barcellos, Fernando Gomes; Prosdocimi, Francisco; May, Gemma; Azevedo Junior, Gilson Martins de; Guimarães, Giselle Moura; Goldman, Gustavo Henrique; Padilha, Itácio Q M; Batista, Jacqueline da Silva; Ferro, Jesus Aparecido; Ribeiro, José M C; Fietto, Juliana Lopes Rangel; Dabbas, Karina Maia; Cerdeira, Louise; Agnez-Lima, Lucymara Fassarella; Brocchi, Marcelo; de Carvalho, Marcos Oliveira; Teixeira, Marcus de Melo; Diniz Maia, Maria de Mascena; Goldman, Maria Helena S; Cruz Schneider, Maria Paula; Felipe, Maria Sueli Soares; Hungria, Mariangela; Nicolás, Marisa Fabiana; Pereira, Maristela; Montes, Martín Alejandro; Cantão, Maurício E; Vincentz, Michel; Rafael, Miriam Silva; Silverman, Neal; Stoco, Patrícia Hermes; Souza, Rangel Celso; Vicentini, Renato; Gazzinelli, Ricardo Tostes; Neves, Rogério de Oliveira; Silva, Rosane; Astolfi-Filho, Spartaco; Maciel, Talles Eduardo Ferreira; Urményi, Turán P; Tadei, Wanderli Pedro; Camargo, Erney Plessmann; de Vasconcelos, Ana Tereza Ribeiro

    2013-08-01

    Anopheles darlingi is the principal neotropical malaria vector, responsible for more than a million cases of malaria per year on the American continent. Anopheles darlingi diverged from the African and Asian malaria vectors ∼100 million years ago (mya) and successfully adapted to the New World environment. Here we present an annotated reference A. darlingi genome, sequenced from a wild population of males and females collected in the Brazilian Amazon. A total of 10 481 predicted protein-coding genes were annotated, 72% of which have their closest counterpart in Anopheles gambiae and 21% have highest similarity with other mosquito species. In spite of a long period of divergent evolution, conserved gene synteny was observed between A. darlingi and A. gambiae. More than 10 million single nucleotide polymorphisms and short indels with potential use as genetic markers were identified. Transposable elements correspond to 2.3% of the A. darlingi genome. Genes associated with hematophagy, immunity and insecticide resistance, directly involved in vector-human and vector-parasite interactions, were identified and discussed. This study represents the first effort to sequence the genome of a neotropical malaria vector, and opens a new window through which we can contemplate the evolutionary history of anopheline mosquitoes. It also provides valuable information that may lead to novel strategies to reduce malaria transmission on the South American continent. The A. darlingi genome is accessible at www.labinfo.lncc.br/index.php/anopheles-darlingi.

  13. The dance of male Anopheles gambiae in mating swarms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mating behavior of the malaria vector Anopheles gambiae is of great interest from a fundamental and applied perspective. One of the most important elements of mating in this species is the crepuscular mating aggregation (swarm) composed almost entirely of males, where most coupling and inseminat...

  14. Workbook on the Identification of Anopheles Adults. Preliminary Issue.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; Stojanovich, Chester J.

    This self-instructional workbook is designed to enable malaria control workers to identify adults of "Anopheles" species that are important malaria vectors. The morphological features of the adults are illustrated in a programed booklet, which also contains an illustrated taxonomic key to adult females of 29 anopheline species. A glossary and a…

  15. Workbook on the Identification of Anopheles Larvae. Preliminary Issue.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; Stojanovich, Chester J.

    This self-instructional booklet is designed to enable malarial control workers to identify the larvae of "Anopheles" species that are important malaria vectors. The morphological features of the larvae are illustrated in a programed booklet, which also contains an illustrated taxonomic key to 25 species of anopheline larvae. A glossary and a short…

  16. The Genome of Anopheles darlingi, the main neotropical malaria vector

    PubMed Central

    Marinotti, Osvaldo; Cerqueira, Gustavo C.; de Almeida, Luiz Gonzaga Paula; Ferro, Maria Inês Tiraboschi; Loreto, Elgion Lucio da Silva; Zaha, Arnaldo; Teixeira, Santuza M. R.; Wespiser, Adam R.; Almeida e Silva, Alexandre; Schlindwein, Aline Daiane; Pacheco, Ana Carolina Landim; da Silva, Artur Luiz da Costa; Graveley, Brenton R.; Walenz, Brian P.; Lima, Bruna de Araujo; Ribeiro, Carlos Alexandre Gomes; Nunes-Silva, Carlos Gustavo; de Carvalho, Carlos Roberto; Soares, Célia Maria de Almeida; de Menezes, Claudia Beatriz Afonso; Matiolli, Cleverson; Caffrey, Daniel; Araújo, Demetrius Antonio M.; de Oliveira, Diana Magalhães; Golenbock, Douglas; Grisard, Edmundo Carlos; Fantinatti-Garboggini, Fabiana; de Carvalho, Fabíola Marques; Barcellos, Fernando Gomes; Prosdocimi, Francisco; May, Gemma; de Azevedo Junior, Gilson Martins; Guimarães, Giselle Moura; Goldman, Gustavo Henrique; Padilha, Itácio Q. M.; Batista, Jacqueline da Silva; Ferro, Jesus Aparecido; Ribeiro, José M. C.; Fietto, Juliana Lopes Rangel; Dabbas, Karina Maia; Cerdeira, Louise; Agnez-Lima, Lucymara Fassarella; Brocchi, Marcelo; de Carvalho, Marcos Oliveira; Teixeira, Marcus de Melo; Diniz Maia, Maria de Mascena; Goldman, Maria Helena S.; Cruz Schneider, Maria Paula; Felipe, Maria Sueli Soares; Hungria, Mariangela; Nicolás, Marisa Fabiana; Pereira, Maristela; Montes, Martín Alejandro; Cantão, Maurício E.; Vincentz, Michel; Rafael, Miriam Silva; Silverman, Neal; Stoco, Patrícia Hermes; Souza, Rangel Celso; Vicentini, Renato; Gazzinelli, Ricardo Tostes; Neves, Rogério de Oliveira; Silva, Rosane; Astolfi-Filho, Spartaco; Maciel, Talles Eduardo Ferreira; Ürményi, Turán P.; Tadei, Wanderli Pedro; Camargo, Erney Plessmann; de Vasconcelos, Ana Tereza Ribeiro

    2013-01-01

    Anopheles darlingi is the principal neotropical malaria vector, responsible for more than a million cases of malaria per year on the American continent. Anopheles darlingi diverged from the African and Asian malaria vectors ∼100 million years ago (mya) and successfully adapted to the New World environment. Here we present an annotated reference A. darlingi genome, sequenced from a wild population of males and females collected in the Brazilian Amazon. A total of 10 481 predicted protein-coding genes were annotated, 72% of which have their closest counterpart in Anopheles gambiae and 21% have highest similarity with other mosquito species. In spite of a long period of divergent evolution, conserved gene synteny was observed between A. darlingi and A. gambiae. More than 10 million single nucleotide polymorphisms and short indels with potential use as genetic markers were identified. Transposable elements correspond to 2.3% of the A. darlingi genome. Genes associated with hematophagy, immunity and insecticide resistance, directly involved in vector–human and vector–parasite interactions, were identified and discussed. This study represents the first effort to sequence the genome of a neotropical malaria vector, and opens a new window through which we can contemplate the evolutionary history of anopheline mosquitoes. It also provides valuable information that may lead to novel strategies to reduce malaria transmission on the South American continent. The A. darlingi genome is accessible at www.labinfo.lncc.br/index.php/anopheles-darlingi. PMID:23761445

  17. Nigeria Anopheles Vector Database: An Overview of 100 Years' Research

    PubMed Central

    Okorie, Patricia Nkem; McKenzie, F. Ellis; Ademowo, Olusegun George; Bockarie, Moses; Kelly-Hope, Louise

    2011-01-01

    Anopheles mosquitoes are important vectors of malaria and lymphatic filariasis (LF), which are major public health diseases in Nigeria. Malaria is caused by infection with a protozoan parasite of the genus Plasmodium and LF by the parasitic worm Wuchereria bancrofti. Updating our knowledge of the Anopheles species is vital in planning and implementing evidence based vector control programs. To present a comprehensive report on the spatial distribution and composition of these vectors, all published data available were collated into a database. Details recorded for each source were the locality, latitude/longitude, time/period of study, species, abundance, sampling/collection methods, morphological and molecular species identification methods, insecticide resistance status, including evidence of the kdr allele, and P. falciparum sporozoite rate and W. bancrofti microfilaria prevalence. This collation resulted in a total of 110 publications, encompassing 484,747 Anopheles mosquitoes in 632 spatially unique descriptions at 142 georeferenced locations being identified across Nigeria from 1900 to 2010. Overall, the highest number of vector species reported included An. gambiae complex (65.2%), An. funestus complex (17.3%), An. gambiae s.s. (6.5%). An. arabiensis (5.0%) and An. funestus s.s. (2.5%), with the molecular forms An. gambiae M and S identified at 120 locations. A variety of sampling/collection and species identification methods were used with an increase in molecular techniques in recent decades. Insecticide resistance to pyrethroids and organochlorines was found in the main Anopheles species across 45 locations. Presence of P. falciparum and W. bancrofti varied between species with the highest sporozoite rates found in An. gambiae s.s, An. funestus s.s. and An. moucheti, and the highest microfilaria prevalence in An. gambiae s.l., An. arabiensis, and An. gambiae s.s. This comprehensive geo-referenced database provides an essential baseline on Anopheles

  18. Urban agriculture and Anopheles habitats in Dar es Salaam, Tanzania.

    PubMed

    Dongus, Stefan; Nyika, Dickson; Kannady, Khadija; Mtasiwa, Deo; Mshinda, Hassan; Gosoniu, Laura; Drescher, Axel W; Fillinger, Ulrike; Tanner, Marcel; Killeen, Gerry F; Castro, Marcia C

    2009-05-01

    A cross-sectional survey of agricultural areas, combined with routinely monitored mosquito larval information, was conducted in urban Dar es Salaam, Tanzania, to investigate how agricultural and geographical features may influence the presence of Anopheles larvae. Data were integrated into a geographical information systems framework, and predictors of the presence of Anopheles larvae in farming areas were assessed using multivariate logistic regression with independent random effects. It was found that more than 5% of the study area (total size 16.8 km2) was used for farming in backyard gardens and larger open spaces. The proportion of habitats containing Anopheles larvae was 1.7 times higher in agricultural areas compared to other areas (95% confidence interval = 1.56-1.92). Significant geographic predictors of the presence of Anopheles larvae in gardens included location in lowland areas, proximity to river, and relatively impermeable soils. Agriculture-related predictors comprised specific seedbed types, mid-sized gardens, irrigation by wells, as well as cultivation of sugar cane or leafy vegetables. Negative predictors included small garden size, irrigation by tap water, rainfed production and cultivation of leguminous crops or fruit trees. Although there was an increased chance of finding Anopheles larvae in agricultural sites, it was found that breeding sites originated by urban agriculture account for less than a fifth of all breeding sites of malaria vectors in Dar es Salaam. It is suggested that strategies comprising an integrated malaria control effort in malaria-endemic African cities include participatory involvement of farmers by planting shade trees near larval habitats.

  19. Distribution and larval habitat characterization of Anopheles moucheti, Anopheles nili, and other malaria vectors in river networks of southern Cameroon.

    PubMed

    Antonio-Nkondjio, Christophe; Ndo, Cyrille; Costantini, Carlo; Awono-Ambene, Parfait; Fontenille, Didier; Simard, Frédéric

    2009-12-01

    Despite their importance as malaria vectors, little is known of the bionomic of Anopheles nili and Anopheles moucheti. Larval collections from 24 sites situated along the dense hydrographic network of south Cameroon were examined to assess key ecological factors associated with these mosquitoes distribution in river networks. Morphological identification of the III and IV instar larvae by the use of microscopy revealed that 47.6% of the larvae belong to An. nili and 22.6% to An. moucheti. Five variables were significantly involved with species distribution, the pace of flow of the river (lotic, or lentic), the light exposure (sunny or shady), vegetation (presence or absence of vegetation) the temperature and the presence or absence of debris. Using canonical correspondence analysis, it appeared that lotic rivers, exposed to light, with vegetation or debris were the best predictors of An. nili larval abundance. Whereas, An. moucheti and An. ovengensis were highly associated with lentic rivers, low temperature, having Pistia. An. nili and An. moucheti distribution along river systems across south Cameroon was highly correlated with environmental variables. The distribution of An. nili conforms to that of a generalist species which is adapted to exploiting a variety of environmental conditions, Whereas, An. moucheti, Anopheles ovengensis and Anopheles carnevalei appeared as specialist forest mosquitoes.

  20. Genomic Islands of Speciation in Anopheles gambiae

    PubMed Central

    Hahn, Matthew W; Nuzhdin, Sergey V

    2005-01-01

    The African malaria mosquito, Anopheles gambiae sensu stricto (A. gambiae), provides a unique opportunity to study the evolution of reproductive isolation because it is divided into two sympatric, partially isolated subtaxa known as M form and S form. With the annotated genome of this species now available, high-throughput techniques can be applied to locate and characterize the genomic regions contributing to reproductive isolation. In order to quantify patterns of differentiation within A. gambiae, we hybridized population samples of genomic DNA from each form to Affymetrix GeneChip microarrays. We found that three regions, together encompassing less than 2.8 Mb, are the only locations where the M and S forms are significantly differentiated. Two of these regions are adjacent to centromeres, on Chromosomes 2L and X, and contain 50 and 12 predicted genes, respectively. Sequenced loci in these regions contain fixed differences between forms and no shared polymorphisms, while no fixed differences were found at nearby control loci. The third region, on Chromosome 2R, contains only five predicted genes; fixed differences in this region were also verified by direct sequencing. These “speciation islands” remain differentiated despite considerable gene flow, and are therefore expected to contain the genes responsible for reproductive isolation. Much effort has recently been applied to locating the genes and genetic changes responsible for reproductive isolation between species. Though much can be inferred about speciation by studying taxa that have diverged for millions of years, studying differentiation between taxa that are in the early stages of isolation will lead to a clearer view of the number and size of regions involved in the genetics of speciation. Despite appreciable levels of gene flow between the M and S forms of A. gambiae, we were able to isolate three small regions of differentiation where genes responsible for ecological and behavioral isolation are

  1. Rice volatiles lure gravid malaria mosquitoes, Anopheles arabiensis.

    PubMed

    Wondwosen, Betelehem; Birgersson, Göran; Seyoum, Emiru; Tekie, Habte; Torto, Baldwyn; Fillinger, Ulrike; Hill, Sharon R; Ignell, Rickard

    2016-11-30

    Mosquito oviposition site selection is essential for vector population dynamics and malaria epidemiology. Irrigated rice cultivations provide ideal larval habitats for malaria mosquitoes, which has resulted in increased prevalence of the malaria vector, Anopheles arabiensis, in sub-Saharan Africa. The nature and origin of the cues regulating this behaviour are only now being elucidated. We show that gravid Anopheles arabiensis are attracted and oviposit in response to the odour present in the air surrounding rice. Furthermore, we identify a synthetic rice odour blend, using electrophysiological and chemical analyses, which elicits attraction and oviposition in laboratory assays, as well as attraction of free-flying gravid mosquitoes under semi-field conditions. This research highlights the intimate link between malaria vectors and agriculture. The identified volatile cues provide important substrates for the development of novel and cost-effective control measures that target female malaria mosquitoes, irrespective of indoor or outdoor feeding and resting patterns.

  2. Rice volatiles lure gravid malaria mosquitoes, Anopheles arabiensis

    PubMed Central

    Wondwosen, Betelehem; Birgersson, Göran; Seyoum, Emiru; Tekie, Habte; Torto, Baldwyn; Fillinger, Ulrike; Hill, Sharon R.; Ignell, Rickard

    2016-01-01

    Mosquito oviposition site selection is essential for vector population dynamics and malaria epidemiology. Irrigated rice cultivations provide ideal larval habitats for malaria mosquitoes, which has resulted in increased prevalence of the malaria vector, Anopheles arabiensis, in sub-Saharan Africa. The nature and origin of the cues regulating this behaviour are only now being elucidated. We show that gravid Anopheles arabiensis are attracted and oviposit in response to the odour present in the air surrounding rice. Furthermore, we identify a synthetic rice odour blend, using electrophysiological and chemical analyses, which elicits attraction and oviposition in laboratory assays, as well as attraction of free-flying gravid mosquitoes under semi-field conditions. This research highlights the intimate link between malaria vectors and agriculture. The identified volatile cues provide important substrates for the development of novel and cost-effective control measures that target female malaria mosquitoes, irrespective of indoor or outdoor feeding and resting patterns. PMID:27901056

  3. The salivary gland chromosomes of Anopheles pseudopunctipennis pseudopunctipennis*

    PubMed Central

    Baker, Richard H.; Kitzmiller, J. B.; Chowdaiah, B. N.

    1965-01-01

    The authors present a salivary chromosome map of Anopheles p. pseudopunctipennis, an important malaria vector in the Americas. The salivary chromosomes appear as a short metacentric X and two metacentric autosomes. The arms of chromosome 2 are of almost equal length, but the right arm of chromosome 3 is almost twice as long as the left. The metacentric X is the first to be described in the subgenus Anopheles. The banding patterns of the autosomes show many similarities to those of the North American maculipennis complex and to those of the Central American A. vestitipennis and A. neomaculipalpus. Three chromosomal aberrations, one in the X and two in the right arm of chromosome 3, occur commonly in several different populations. ImagesFIG. 3FIG. 5FIG. 6FIG. 7 PMID:5295407

  4. Seasonality and Locality Affect the Diversity of Anopheles gambiae and Anopheles coluzzii Midgut Microbiota from Ghana

    PubMed Central

    Gendrin, Mathilde; Pels, Nana Adjoa P.; Yeboah-Manu, Dorothy; Christophides, George K.; Wilson, Michael D.

    2016-01-01

    Symbiotic bacteria can have important implications in the development and competence of disease vectors. In Anopheles mosquitoes, the composition of the midgut microbiota is largely influenced by the larval breeding site, but the exact factors shaping this composition are currently unknown. Here, we examined whether the proximity to urban areas and seasons have an impact on the midgut microbial community of the two major malaria vectors in Africa, An. coluzzii and An. gambiae. Larvae and pupae were collected from selected habitats in two districts of Ghana during the dry and rainy season periods. The midgut microbiota of adults that emerged from these collections was determined by 454-pyrosequencing of the 16S ribosomal DNA. We show that in both mosquito species, Shewanellaceae constituted on average of 54% and 73% of the midgut microbiota from each site in the dry and rainy season, respectively. Enterobacteriaceae was found in comparatively low abundance below 1% in 22/30 samples in the dry season, and in 25/38 samples in the rainy season. Our data indicate that seasonality and locality significantly affect both the diversity of microbiota and the relative abundance of bacterial families with a positive impact of dry season and peri-urban settings. PMID:27322614

  5. Multimodal Pyrethroid Resistance in Malaria Vectors, Anopheles gambiae s.s., Anopheles arabiensis, and Anopheles funestus s.s. in Western Kenya

    PubMed Central

    Kawada, Hitoshi; Dida, Gabriel O.; Ohashi, Kazunori; Komagata, Osamu; Kasai, Shinji; Tomita, Takashi; Sonye, George; Maekawa, Yoshihide; Mwatele, Cassian; Njenga, Sammy M.; Mwandawiro, Charles; Minakawa, Noboru; Takagi, Masahiro

    2011-01-01

    Anopheles gambiae s.s., Anopheles arabiensis, and Anopheles funestus s.s. are the most important species for malaria transmission. Pyrethroid resistance of these vector mosquitoes is one of the main obstacles against effective vector control. The objective of the present study was to monitor the pyrethroid susceptibility in the 3 major malaria vectors in a highly malaria endemic area in western Kenya and to elucidate the mechanisms of pyrethroid resistance in these species. Gembe East and West, Mbita Division, and 4 main western islands in the Suba district of the Nyanza province in western Kenya were used as the study area. Larval and adult collection and bioassay were conducted, as well as the detection of point mutation in the voltage-gated sodium channel (1014L) by using direct DNA sequencing. A high level of pyrethroid resistance caused by the high frequency of point mutations (L1014S) was detected in An. gambiae s.s. In contrast, P450-related pyrethroid resistance seemed to be widespread in both An. arabiensis and An. funestus s.s. Not a single L1014S mutation was detected in these 2 species. A lack of cross-resistance between DDT and permethrin was also found in An. arabiensis and An. funestus s.s., while An. gambiae s.s. was resistant to both insecticides. It is noteworthy that the above species in the same area are found to be resistant to pyrethroids by their unique resistance mechanisms. Furthermore, it is interesting that 2 different resistance mechanisms have developed in the 2 sibling species in the same area individually. The cross resistance between permethrin and DDT in An. gambiae s.s. may be attributed to the high frequency of kdr mutation, which might be selected by the frequent exposure to ITNs. Similarly, the metabolic pyrethroid resistance in An. arabiensis and An. funestus s.s. is thought to develop without strong selection by DDT. PMID:21853038

  6. Diversity of the Bacterial Microbiota of Anopheles Mosquitoes from Binh Phuoc Province, Vietnam.

    PubMed

    Ngo, Chung T; Romano-Bertrand, Sara; Manguin, Sylvie; Jumas-Bilak, Estelle

    2016-01-01

    The naturally acquired microbiota of Anopheles can influence vector's susceptibility to Plasmodium and its capacity to transmit them. Microbiota modification is a new challenge to limit disease transmission but it still needs advanced knowledges on bacterial community in Anopheles, especially in wild and infected specimens from diverse origin and species. Bacterial culture and 16S rRNA gene-PCR associated to Temporal Temperature Gradient Electrophoresis (TTGE) were applied to explore the bacterial diversity in the abdomen of 100 wild specimens (eight Anopheles species) collected in the Binh Phuoc Province, Vietnam. Culture and PCR-TTGE were complementary. The bacterial richness of the mosquito collection encompassed 105 genera belonging to seven phyla, mostly Proteobacteria, Firmicutes, and Actinobacteria. Staphylococcus, Clostridium, and Bacillus in Firmicutes were the most prevalent genera. However, Proteobacteria represented by 57 genera was the most diversified phylum in Anopheles microbiota. The high overall of Anopheles-associated bacteria is confirmed with, to our knowledge, 51 genera described for the first time in Anopheles microbiota. However, the diversity per specimen was low with average diversity index and the average Shannon-Wiener score (H) of 4.843 and 5.569, respectively. The most represented bacterial genera were present in <30% of the specimens. Consequently, the core microbiota share by Anopheles from Binh Phuoc was very narrow, suggesting that Anopheles microbiota was greatly influenced by local environments. The repertory of bacterial genera in two specimens of An. dirus and An. pampanai naturally infected by Plasmodium vivax was also described as preliminary results. Finally, this study completed the repertory of bacteria associated to wild Anopheles. Anopheles associated-bacteria appeared specimen-dependent rather than mosquitoe species- or group-dependent. Their origin and the existence of Anopheles-specific bacterial taxa are discussed.

  7. Diversity of the Bacterial Microbiota of Anopheles Mosquitoes from Binh Phuoc Province, Vietnam

    PubMed Central

    Ngo, Chung T.; Romano-Bertrand, Sara; Manguin, Sylvie; Jumas-Bilak, Estelle

    2016-01-01

    The naturally acquired microbiota of Anopheles can influence vector’s susceptibility to Plasmodium and its capacity to transmit them. Microbiota modification is a new challenge to limit disease transmission but it still needs advanced knowledges on bacterial community in Anopheles, especially in wild and infected specimens from diverse origin and species. Bacterial culture and 16S rRNA gene-PCR associated to Temporal Temperature Gradient Electrophoresis (TTGE) were applied to explore the bacterial diversity in the abdomen of 100 wild specimens (eight Anopheles species) collected in the Binh Phuoc Province, Vietnam. Culture and PCR-TTGE were complementary. The bacterial richness of the mosquito collection encompassed 105 genera belonging to seven phyla, mostly Proteobacteria, Firmicutes, and Actinobacteria. Staphylococcus, Clostridium, and Bacillus in Firmicutes were the most prevalent genera. However, Proteobacteria represented by 57 genera was the most diversified phylum in Anopheles microbiota. The high overall of Anopheles-associated bacteria is confirmed with, to our knowledge, 51 genera described for the first time in Anopheles microbiota. However, the diversity per specimen was low with average diversity index and the average Shannon–Wiener score (H) of 4.843 and 5.569, respectively. The most represented bacterial genera were present in <30% of the specimens. Consequently, the core microbiota share by Anopheles from Binh Phuoc was very narrow, suggesting that Anopheles microbiota was greatly influenced by local environments. The repertory of bacterial genera in two specimens of An. dirus and An. pampanai naturally infected by Plasmodium vivax was also described as preliminary results. Finally, this study completed the repertory of bacteria associated to wild Anopheles. Anopheles associated-bacteria appeared specimen-dependent rather than mosquitoe species- or group-dependent. Their origin and the existence of Anopheles-specific bacterial taxa are

  8. Developing transgenic Anopheles mosquitoes for the sterile insect technique.

    PubMed

    Nolan, Tony; Papathanos, Philippos; Windbichler, Nikolai; Magnusson, Kalle; Benton, Jason; Catteruccia, Flaminia; Crisanti, Andrea

    2011-01-01

    In the last 10 years the availability of the genome sequence of Anopheles gambiae and the development of a transgenic technology for several species of Anopheles mosquitoes have, in combination, helped in enabling us to gain several insights into the biology of these mosquitoes that is relevant to their capacity as vectors of the malaria parasite. While this information is anticipated to inform many novel vector control strategies, the technique most likely to benefit in the near future from the availability of a reliable transgenic technology is the sterile insect technique (SIT), which relies on releasing large numbers of sterile insects to compete for mates in the wild, leading to population suppression. Although SIT has been proven to work reliably for many insects, the construction of suitable strains, and induction of sterility, has until now been a laborious process, combining classical genetics with radiation-induced sterility. Using transgenesis to create strains of Anopheles suitable for SIT could potentially offer several advantages over current approaches, in that the basic design of transgenic constructs designed for other insects should be rapidly transferable to mosquitoes, and induction of sterility as a product of the transgenic modification could obviate the requirement for radiation and its associated deleterious effects. In this paper the progress of different transgenic approaches in constructing tools for SIT will be reviewed.

  9. Evolution of an Epigenetic Gene Ensemble within the Genus Anopheles

    PubMed Central

    Jenkins, Adam M.; Muskavitch, Marc A.T.

    2015-01-01

    Epigenetic control of gene expression has important implications for the regulation of developmental processes, for mediating homeostasis and responses to the external environment, and for transgenerational inheritance of gene expression patterns. Genes that mediate epigenetic control have been well-characterized in Drosophila melanogaster, and we have identified and analyzed an orthologous gene ensemble in Anopheles gambiae that comprises 169 orthologs related to a 215-member epigenetic gene ensemble in D. melanogaster. We find that this ensemble is highly conserved among anopheline mosquitoes, as we identify only seven gene family expansion/contraction events within the ensemble among 12 mosquito species we have studied within the genus Anopheles. Comparative analyses of the epigenetic gene expression across the genera Drosophila and Anopheles reveal distinct tissue-associated expression patterns in the two genera, but similar temporal expression patterns. The A. gambiae complex and D. melanogaster subgroup epigenetic gene ensembles exhibit similar evolutionary rates, as assessed by their respective dN/dS values. These differences in tissue-associated expression patterns, in contrast to similarities in evolutionary rates and temporal expression patterns, may imply that some members of the epigenetic gene ensemble have been redeployed within one or both genera, in comparison to the most recent common ancestor of these two clades. Members of this epigenetic gene ensemble may constitute another set of potential targets for vector control and enable further reductions in the burden of human malaria, by analogy to recent success in development of small molecule antagonists for mammalian epigenetic machinery. PMID:25724208

  10. Mosquito biosurveillance on Kyushu Island, Japan, with emphasis on Anopheles Hyrcanus Group and related species (Diptera: culicidae).

    PubMed

    Rueda, Leopoldo M; Pagac, Benedict; Iwakami, Masashiro; Spring, Alexandra R; Motoki, Mayasa T; Pecor, James E; Higa, Yukiko; Futami, Kyoko; Imanishi, Nozomi; Long, Lewis S; Debboun, Mustapha

    2014-01-01

    This report includes the distribution records of the Anopheles (Anopheles) Hyrcanus Group and associated species in Kyushu Island, Japan, based on our field collections from various localities of 4 prefectures (Fukuoka, Kumamoto, Nagasaki, Saga), primarily from 2002-2013. The status of common and potential mosquito vectors, particularly Anopheles species, in Japan are noted.

  11. The Physical Genome Mapping of Anopheles albimanus Corrected Scaffold Misassemblies and Identified Interarm Rearrangements in Genus Anopheles

    PubMed Central

    Artemov, Gleb N.; Peery, Ashley N.; Jiang, Xiaofang; Tu, Zhijian; Stegniy, Vladimir N.; Sharakhova, Maria V.; Sharakhov, Igor V.

    2016-01-01

    The genome of the Neotropical malaria vector Anopheles albimanus was sequenced as part of the 16 Anopheles Genomes Project published in 2015. The draft assembly of this species consisted of 204 scaffolds with an N50 scaffold size of 18.1 Mb and a total assembly size of 170.5 Mb. It was among the smallest genomes with the longest scaffolds in the 16 Anopheles species cluster, making An. albimanus the logical choice for anchoring the genome assembly to chromosomes. In this study, we developed a high-resolution cytogenetic photomap with completely straightened polytene chromosomes from the salivary glands of the mosquito larvae. Based on this photomap, we constructed a chromosome-based genome assembly using fluorescent in situ hybridization of PCR-amplified DNA probes. Our physical mapping, assisted by an ortholog-based bioinformatics approach, identified and corrected nine misassemblies in five large genomic scaffolds. Misassemblies mostly occurred in junctions between contigs. Our comparative analysis of scaffolds with the An. gambiae genome detected multiple genetic exchanges between pericentromeric regions of chromosomal arms caused by partial-arm translocations. The final map consists of 40 ordered genomic scaffolds and corrected fragments of misassembled scaffolds. The An. albimanus physical map comprises 98.2% of the total genome assembly and represents the most complete genome map among mosquito species. This study demonstrates that physical mapping is a powerful tool for correcting errors in draft genome assemblies and for creating chromosome-anchored reference genomes. PMID:27821634

  12. Monooxygenase Levels and Knockdown Resistance (kdr) Allele Frequencies in Anopheles gambiae and Anopheles arabiensis in Kenya

    PubMed Central

    Chen, Hong; Githeko, Andrew K; Githure, John I; Mutunga, James; Zhou, Guofa; Yan, Guiyun

    2013-01-01

    Pyrethroid-treated bed nets and indoor spray are important components of malaria control strategies in Kenya. Information on resistance to pyrethroid insecticides in Anopheles gambiae and An. arabiensis populations is essential to the selection of appropriate insecticides and the management of insecticide resistance. Monooxygenase activity and knockdown resistance (kdr) allele frequency are biochemical and molecular indicators of mosquito resistance to pyrethroids. This study determined baseline information on monooxygenase activity and kdr allele frequency in anopheline mosquitoes in the western region, the Great Rift Valley-central province region, and the coastal region of Kenya. A total of 1990 field-collected individuals, representing 12 An. gambiae and 22 An. arabiensis populations was analyzed. We found significant among-population variation in monooxygenase activity in An. gambiae and An. arabiensis and substantial variability among individuals within populations. Nine out of 12 An. gambiae populations exhibited significantly higher average monooxygenase activity than the susceptible Kisumu reference strain. The kdr alleles (L1014S) were detected in three An. gambiae populations, and one An. arabiensis population in western Kenya, but not in the Rift Valley-central region and the coastal Kenya region. All genotypes with the kdr alleles were heterozygous, and the conservative estimation of kdr allele frequency was below 1% in these four populations. Information on monooxygenase activity and kdr allele frequency reported in this study provided baseline data for monitoring insecticide resistance changes in Kenya during the era when large-scale insecticide-treated bednet and indoor residual spray campaigns were being implemented. PMID:18402140

  13. ANOSPEX: A Stochastic, Spatially Explicit Model for Studying Anopheles Metapopulation Dynamics

    PubMed Central

    Oluwagbemi, Olugbenga O.; Fornadel, Christen M.; Adebiyi, Ezekiel F.; Norris, Douglas E.; Rasgon, Jason L.

    2013-01-01

    Anopheles mosquitoes transmit malaria, a major public health problem among many African countries. One of the most effective methods to control malaria is by controlling the Anopheles mosquito vectors that transmit the parasites. Mathematical models have both predictive and explorative utility to investigate the pros and cons of different malaria control strategies. We have developed a C++ based, stochastic spatially explicit model (ANOSPEX; AnophelesSpatially-Explicit) to simulate Anopheles metapopulation dynamics. The model is biologically rich, parameterized by field data, and driven by field-collected weather data from Macha, Zambia. To preliminarily validate ANOSPEX, simulation results were compared to field mosquito collection data from Macha; simulated and observed dynamics were similar. The ANOSPEX model will be useful in a predictive and exploratory manner to develop, evaluate and implement traditional and novel strategies to control malaria, and for understanding the environmental forces driving Anopheles population dynamics. PMID:23861847

  14. Biting patterns and seasonality of anopheles gambiae sensu lato and anopheles funestus mosquitoes in Kamuli District, Uganda

    PubMed Central

    2013-01-01

    Background We investigated the biting patterns and seasonal abundances of Anopheles gambiae s.l. and An. funestus mosquitoes in Kamuli District, Uganda. Methods Hourly indoor and outdoor catches of human biting mosquitoes were sampled from 19.00 to 07.00 hours for four consecutive nights each month using bed net traps in forty-eight houses randomly selected from Bugabula county where insecticide-treated bed nets (ITNs) had been used for at least five years and Budiope county where ITNs had not been used. The indoor and outdoor human-biting fractions, time of biting of the anophelines and climatic data were recorded from January to December 2010. Data were analysed using Multi-way analysis of variance, Kruskal-wallis rank sum test and Pearson correlation. The number of mosquitoes caught biting humans and resting indoors, the indoor and outdoor human biting densities and biting rates during different hours of the night, and mosquito abundances for a twelve-month sampling period in both zones are reported. Results Approximately four times more Anopheles mosquitoes were caught biting humans in Budiope County than in the Bugabula zone, with An. gambiae s. l. catches exceeding those of An. funestus. In both zones, peak night biting occurred between 23.00 and 05.00 hours. The majority of bites occurred between 03.00 and 06.00 hours for both Anopheles gambiae s. l. and funestus group. Outdoor biting densities of Anopheles gambiae s. l. exceeded the indoor biting densities throughout the night in both zones, while the indoor and outdoor human biting densities of An. funestus group were apparently equal. The outdoor and indoor human biting rates were similar in both zones. In Bugabula county, the abundance of An. gambiae s.l. was rainfall-dependent, while the An. funestus group could thrive with or without rain fall. In Budiope county, both An. gambiae s.l. and An. funestus mosquitoes thrived all year round regardless of the amount of rainfall. Conclusion Considering the

  15. Differential susceptibilities of Anopheles albimanus and Anopheles pseudopunctipennis to infections with coindigenous Plasmodium vivax variants VK210 and VK247 in southern Mexico.

    PubMed

    Gonzalez-Ceron, L; Rodriguez, M H; Nettel, J C; Villarreal, C; Kain, K C; Hernandez, J E

    1999-01-01

    The susceptibilities to coindigenous Plasmodium vivax of colonized Anopheles albimanus and Anopheles pseudopunctipennis from southern Mexico were investigated by simultaneous feeding with infected blood obtained from patients. The genes encoding circumsporozoite protein variant types (VK210 and VK247) in blood samples were determined by PCR and oligonucleotide probe hybridization. A. albimanus was more susceptible to VK210, and A. pseudopunctipennis was more susceptible to VK247.

  16. Discovery of flavivirus-derived endogenous viral elements in Anopheles mosquito genomes supports the existence of Anopheles-associated insect-specific flaviviruses.

    PubMed

    Lequime, Sebastian; Lambrechts, Louis

    2017-01-01

    The Flavivirus genus encompasses several arboviruses of public health significance such as dengue, yellow fever, and Zika viruses. It also includes insect-specific flaviviruses (ISFs) that are only capable of infecting insect hosts. The vast majority of mosquito-infecting flaviviruses have been associated with mosquito species of the Aedes and Culex genera in the Culicinae subfamily, which also includes most arbovirus vectors. Mosquitoes of the Anophelinae subfamily are not considered significant arbovirus vectors; however, flaviviruses have occasionally been detected in field-caught Anopheles specimens. Whether such observations reflect occasional spillover or laboratory contamination or whether Anopheles mosquitoes are natural hosts of flaviviruses is unknown. Here, we provide in silico and in vivo evidence of transcriptionally active, flavivirus-derived endogenous viral elements (EVEs) in the genome of Anopheles minimus and Anopheles sinensis. Such non-retroviral endogenization of RNA viruses is consistent with a shared evolutionary history between flaviviruses and Anopheles mosquitoes. Phylogenetic analyses of the two newly described EVEs support the existence of a distinct clade of Anopheles-associated ISFs.

  17. Discovery of flavivirus-derived endogenous viral elements in Anopheles mosquito genomes supports the existence of Anopheles-associated insect-specific flaviviruses

    PubMed Central

    Lequime, Sebastian; Lambrechts, Louis

    2017-01-01

    The Flavivirus genus encompasses several arboviruses of public health significance such as dengue, yellow fever, and Zika viruses. It also includes insect-specific flaviviruses (ISFs) that are only capable of infecting insect hosts. The vast majority of mosquito-infecting flaviviruses have been associated with mosquito species of the Aedes and Culex genera in the Culicinae subfamily, which also includes most arbovirus vectors. Mosquitoes of the Anophelinae subfamily are not considered significant arbovirus vectors; however, flaviviruses have occasionally been detected in field-caught Anopheles specimens. Whether such observations reflect occasional spillover or laboratory contamination or whether Anopheles mosquitoes are natural hosts of flaviviruses is unknown. Here, we provide in silico and in vivo evidence of transcriptionally active, flavivirus-derived endogenous viral elements (EVEs) in the genome of Anopheles minimus and Anopheles sinensis. Such non-retroviral endogenization of RNA viruses is consistent with a shared evolutionary history between flaviviruses and Anopheles mosquitoes. Phylogenetic analyses of the two newly described EVEs support the existence of a distinct clade of Anopheles-associated ISFs. PMID:28078104

  18. Environmental factors associated with spatial and temporal distribution of Anopheles (Diptera: Culicidae) larvae in Sukabumi, West Java, Indonesia.

    PubMed

    Stoops, Craig A; Gionar, Yoyo R; Shinta; Sismadi, Priyanto; Elyazar, Iqbal R F; Bangs, Michael J; Sukowati, Supratman

    2007-07-01

    A 12-mo ecological study of the spatial-temporal distribution of immature stages of Anopheles species was conducted in Sukabumi District, West Java, Indonesia. The study characterized 1,600 sites from a contiguous coastal and hill zone (0-800-m elevation) of which 64% contained Anopheles larvae. Principal component and multiple logistic regression analyses identified ecological parameters associated with presence of nine [Anopheles aconitus Doenitz, Anopheles annularis Van de Wulp, Anopheles barbirostris Van der Wulp, Anopheles flavirostris (Ludlow), Anopheles insulaeflorum (Swellengrebel and Swellengrebel de Graaf), Anopheles kochi Doenitz, Anopheles maculatus Theobald, Anopheles sundaicus (Rodenwaldt), and Anopheles vagus Doenitz] of 15 Anopheles species collected. Combined data for all nine species showed increased Anopheles presence associated with wet season periods and higher elevation habitats exhibiting reduced tree canopy coverage, higher water temperatures, and shallower water depths. Habitat variables measured included topography (elevation), water conditions (temperature, pH, salinity depth, and velocity), habitat characteristics (substrate and canopy cover), density and type of aquatic vegetation coverage (riparian, floating, and emergent), and distance from nearest human habitation. Significant relationships were found for nine species when using all habitats in the analysis. Habitat characteristics for three species were refined. An. aconitus and An. barbirostris were associated with higher elevation rice, Oryza savita L., paddies with relatively shallow water depths, higher water temperatures, higher acidity and salinity concentrations, and a greater average distance from human habitation. An. vagus presence in rice paddies was associated with lower elevation fields, deeper and cooler water, less acidic and saline conditions, and habitats closer to human dwellings. Overall, the distribution of Anopheles species in Sukabumi was found to be nonrandom

  19. Population Genetics of Anopheles coluzzii Immune Pathways and Genes

    PubMed Central

    Rottschaefer, Susan M.; Crawford, Jacob E.; Riehle, Michelle M.; Guelbeogo, Wamdaogo M.; Gneme, Awa; Sagnon, N’Fale; Vernick, Kenneth D.; Lazzaro, Brian P.

    2014-01-01

    Natural selection is expected to drive adaptive evolution in genes involved in host–pathogen interactions. In this study, we use molecular population genetic analyses to understand how natural selection operates on the immune system of Anopheles coluzzii (formerly A. gambiae “M form”). We analyzed patterns of intraspecific and interspecific genetic variation in 20 immune-related genes and 17 nonimmune genes from a wild population of A. coluzzii and asked if patterns of genetic variation in the immune genes are consistent with pathogen-driven selection shaping the evolution of defense. We found evidence of a balanced polymorphism in CTLMA2, which encodes a C-type lectin involved in regulation of the melanization response. The two CTLMA2 haplotypes, which are distinguished by fixed amino acid differences near the predicted peptide cleavage site, are also segregating in the sister species A. gambiae (“S form”) and A. arabiensis. Comparison of the two haplotypes between species indicates that they were not shared among the species through introgression, but rather that they arose before the species divergence and have been adaptively maintained as a balanced polymorphism in all three species. We additionally found that STAT-B, a retroduplicate of STAT-A, shows strong evidence of adaptive evolution that is consistent with neofunctionalization after duplication. In contrast to the striking patterns of adaptive evolution observed in these Anopheles-specific immune genes, we found no evidence of adaptive evolution in the Toll and Imd innate immune pathways that are orthologously conserved throughout insects. Genes encoding the Imd pathway exhibit high rates of amino acid divergence between Anopheles species but also display elevated amino acid diversity that is consistent with relaxed purifying selection. These results indicate that adaptive coevolution between A. coluzzii and its pathogens is more likely to involve novel or lineage-specific molecular mechanisms

  20. Low rates of multiple fertilization in parous Anopheles albimanus.

    PubMed

    Villarreal, C; Fuentes-Maldonado, G; Rodriguez, M H; Yuval, B

    1994-03-01

    We determined how frequently parous female Anopheles albimanus fertilize their eggs with sperm from more than one male. To establish paternity we relied on 2 phenotypically distinct laboratory strains. Nulliparous females were allowed to mate freely with males from one strain, and after oviposition they were offered a 2nd mating with males of the other strain. Fertilization patterns were determined by the phenotypes of offspring. Only 0.6% of females ovipositing for a 2nd time (n = 312) used sperm from the 2nd male, as did 4% of females completing a 3rd gonotrophic cycle (n = 25). In this species receptivity is not routinely renewed following oviposition.

  1. G Protein-Coupled Receptors in Anopheles gambiae

    NASA Astrophysics Data System (ADS)

    Hill, Catherine A.; Fox, A. Nicole; Pitts, R. Jason; Kent, Lauren B.; Tan, Perciliz L.; Chrystal, Mathew A.; Cravchik, Anibal; Collins, Frank H.; Robertson, Hugh M.; Zwiebel, Laurence J.

    2002-10-01

    We used bioinformatic approaches to identify a total of 276 G protein-coupled receptors (GPCRs) from the Anopheles gambiae genome. These include GPCRs that are likely to play roles in pathways affecting almost every aspect of the mosquito's life cycle. Seventy-nine candidate odorant receptors were characterized for tissue expression and, along with 76 putative gustatory receptors, for their molecular evolution relative to Drosophila melanogaster. Examples of lineage-specific gene expansions were observed as well as a single instance of unusually high sequence conservation.

  2. Genetic Structure of Anopheles (Nyssorhynchus) marajoara (Diptera: Culicidae) in Colombia

    DTIC Science & Technology

    2010-01-01

    587GENETIC STRUCTURE OF ANOPHELES MARAJOARA IN COLOMBIA were sampled ( Figure 2 ). These populations were from Cáceres, Antioquia Department, 07°34...M5-71 (9; Meta), M5-71 (7; Norte de Santander), M1-31 and M10-1 (7 each; Magdalena), and M5-71 , M6-8 , and M7-1 (6 each; Antioquia ). In...2.07) and Antioquia (n A = 4.89 ± 1.27); Norte de Santander (n A = 5.33 ± 1.32) and Magdalena (n A = 5.53 ± 1.07) yielded intermediate values, and

  3. PCR identification and distribution of Anopheles daciae (Diptera, Culicidae) in Germany.

    PubMed

    Kronefeld, Mandy; Werner, Doreen; Kampen, Helge

    2014-06-01

    Based primarily on nucleotide polymorphisms in the internal transcribed spacer 2 (ITS2) of the ribosomal DNA, Anopheles daciae was recently described as an additional member of the Maculipennis Group of species, separate from Anopheles messeae with which it had previously been confused due to morphological and genetic similarity. Species differentiation between A. messeae and A. daciae was possible only by ITS2 polymerase chain reaction (PCR) amplification followed by DNA sequencing or RFLP analysis. In addition to its siblings, Anopheles maculipennis, Anopheles atroparvus and A. messeae, A. daciae has been shown to occur in Germany, although with limited distribution. We here describe additional collection sites for this species in Germany, showing concentrations in East Germany and the northern Upper Rhine Valley in Southwest Germany. A species-specific multiplex PCR assay is presented that is able to differentiate the four Maculipennis Group sibling species occurring in Germany plus Anopheles sacharovi, Anopheles melanoon and Anopheles labranchiae. The correct identification and detailed knowledge of the biology of A. daciae are of relevance since it might be a vector of disease agents, as suggested by the vector potential of its siblings and the recent finding of an A. daciae female infected with Dirofilaria repens in southern Germany.

  4. Biting patterns and seasonal densities of Anopheles mosquitoes in the Cayo District, Belize, Central America with emphasis on Anopheles darlingi.

    PubMed

    Achee, Nicole L; Grieco, John P; Rejmankova, Eliska; Andre, Richard G; Vanzie, Errol; Polanco, Jorge; Briceno, Ireneo; King, Russell; Roberts, Donald R

    2006-06-01

    The present study utilized an experimental hut to conduct human-baited landing collections for characterizing the all-night biting patterns and seasonal densities of adult Anopheles darlingi in the centrally located Cayo District of Belize, Central America. A total of 25 all-night collections (i.e., sunset to sunrise) were conducted from January 2002 to May 2003, capturing a total of 18,878 An. darlingi females. Anopheles darlingi exhibited a bimodal nightly biting pattern with one predominate peak occurring three h after sunset and a smaller peak occurring one h prior to sunrise. Biting females were collected throughout the night in higher densities indoors (9,611) than outside (9,267) the experimental hut (O:I=1.00:1.04). Seasonal adult collections show An. darlingi densities were highest during the transitional months between the end of the wet and beginning of the dry season (January) and the end of the dry season and beginning of the wet season (May). A total of 2,010 An. darlingi females was captured in 31 two-h, human-baited landing collections performed from January to October 2002. Anopheles darlingi monthly population densities were found to have no significant associations with high or low temperatures, precipitation, or river level. However, qualitative data examination indicates an inverse relationship between river level and An. darlingi adult collections suggesting a disturbance of larval habitats. All-night biting and seasonal distribution patterns for other anopheline species are also described. None of the adult specimens collected throughout the entire study tested positive for Plasmodium spp. infection using the VecTest rapid diagnostic kit.

  5. Stable and fluctuating temperature effects on the development rate and survival of two malaria vectors, Anopheles arabiensis and Anopheles funestus

    PubMed Central

    2013-01-01

    Background Understanding the biology of malaria vector mosquitoes is crucial to understanding many aspects of the disease, including control and future outcomes. The development rates and survival of two Afrotropical malaria vectors, Anopheles arabiensis and Anopheles funestus, are investigated here under conditions of constant and fluctuating temperatures. These data can provide a good starting point for modelling population level consequences of temperature change associated with climate change. For comparative purposes, these data were considered explicitly in the context of those available for the third African malaria vector, Anopheles gambiae. Methods Twenty five replicates of 20–30 eggs were placed at nine constant and two fluctuating temperatures for development rate experiments and survival estimates. Various developmental parameters were estimated from the data, using standard approaches. Results Lower development threshold (LDT) for both species was estimated at 13-14°C. Anopheles arabiensis developed consistently faster than An. funestus. Optimum temperature (Topt) and development rate at this temperature (μmax) differed significantly between species for overall development and larval development. However, Topt and μmax for pupal development did not differ significantly between species. Development rate and survival of An. funestus was negatively influenced by fluctuating temperatures. By contrast, development rate of An. arabiensis at fluctuating temperatures either did not differ from constant temperatures or was significantly faster. Survival of this species declined by c. 10% at the 15°C to 35°C fluctuating temperature regime, but was not significantly different between the constant 25°C and the fluctuating 20°C to 30°C treatment. By comparison, previous data for An. gambiae indicated fastest development at a constant temperature of 28°C and highest survival at 24°C. Conclusions The three most important African malaria vectors all differ

  6. Experimental Plasmodium vivax infection of key Anopheles species from the Brazilian Amazon

    PubMed Central

    2013-01-01

    Background Anopheles darlingi is the major malaria vector in countries located in the Amazon region. Anopheles aquasalis and Anopheles albitarsis s.l. are also proven vectors in this region. Anopheles nuneztovari s.l. and Anopheles triannulatus s.l. were found infected with Plasmodium vivax; however, their status as vectors is not yet well defined. Knowledge of susceptibility of Amazon anopheline populations to Plasmodium infection is necessary to better understand their vector capacity. Laboratory colonization of An. darlingi, the main Amazon vector, has proven to be difficult and presently An. aquasalis is the only available autonomous colony. Methods Larvae of An. darlingi, An. albitarsis s.l., An. nuneztovari s.l. and An. triannulatus s.l. were collected in the field and reared until adult stage. Adults of An. aquasalis were obtained from a well-established colony. Mosquitoes were blood-fed using a membrane-feeding device containing infected blood from malarial patients. The infection of the distinct Anopheles species was evaluated by the impact variance of the following parameters: (a) parasitaemia density; (b) blood serum inactivation of the infective bloodmeal; (c) influence of gametocyte number on infection rates and number of oocysts. The goal of this work was to compare the susceptibility to P. vivax of four field-collected Anopheles species with colonized An. aquasalis. Results All Anopheles species tested were susceptible to P. vivax infection, nevertheless the proportion of infected mosquitoes and the infection intensity measured by oocyst number varied significantly among species. Inactivation of the blood serum prior to mosquito feeding increased infection rates in An. darlingi and An. triannulatus s.l., but was diminished in An. albitarsis s.l. and An. aquasalis. There was a positive correlation between gametocyte density and the infection rate in all tests (Z = −8.37; p < 0.001) but varied among the mosquito species. Anopheles albitarsis

  7. Gene Expression-Based Biomarkers for Anopheles gambiae Age Grading

    PubMed Central

    Wang, Mei-Hui; Marinotti, Osvaldo; Zhong, Daibin; James, Anthony A.; Walker, Edward; Guda, Tom; Kweka, Eliningaya J.; Githure, John; Yan, Guiyun

    2013-01-01

    Information on population age structure of mosquitoes under natural conditions is fundamental to the understanding of vectorial capacity and crucial for assessing the impact of vector control measures on malaria transmission. Transcriptional profiling has been proposed as a method for predicting mosquito age for Aedes and Anopheles mosquitoes, however, whether this new method is adequate for natural conditions is unknown. This study tests the applicability of transcriptional profiling for age-grading of Anopheles gambiae, the most important malaria vector in Africa. The transcript abundance of two An. gambiae genes, AGAP009551 and AGAP011615, was measured during aging under laboratory and field conditions in three mosquito strains. Age-dependent monotonic changes in transcript levels were observed in all strains evaluated. These genes were validated as age-grading biomarkers using the mark, release and recapture (MRR) method. The MRR method determined a good correspondence between actual and predicted age, and thus demonstrated the value of age classifications derived from the transcriptional profiling of these two genes. The technique was used to establish the age structure of mosquito populations from two malaria-endemic areas in western Kenya. The population age structure determined by the transcriptional profiling method was consistent with that based on mosquito parity. This study demonstrates that the transcription profiling method based on two genes is valuable for age determination of natural mosquitoes, providing a new approach for determining a key life history trait of malaria vectors. PMID:23936017

  8. Anophelism in a Former Malaria Area of Northeastern Spain

    PubMed Central

    Bueno-Marí, Rubén; Jiménez-Peydró, Ricardo

    2013-01-01

    Background: A field study on diversity and distribution of anophelines currently present in a past endemic malaria area of Spain was carried out in order to identify possible risk areas of local disease transmission. Methods: Multiple larval sites were sampled from June to October of 2011 in the Region of Somontano de Barbastro (Northeastern Spain). The sampling effort was fixed at 10 minutes which included the active search for larvae in each biotope visited. Results: A total of 237 larval specimens belonging to four Anopheles species (Anopheles atroparvus, An. claviger, An. maculipennis and An. petragnani) were collected and identified. Conclusions: Malaria receptivity in the study area is high, especially in the area of Cinca river valley, due to the abundance of breeding sites of An. atroparvus very close to human settlements. Although current socio-economic conditions in Spain reduce possibilities of re-emergence of malaria transmission, it is evident that certain entomological and epidemiological vigilance must be maintained and even increased in the context of current processes of climate change and globalization. PMID:24409440

  9. Dosage Compensation in the African Malaria Mosquito Anopheles gambiae

    PubMed Central

    Rose, Graham; Krzywinska, Elzbieta; Kim, Jan; Revuelta, Loic; Ferretti, Luca; Krzywinski, Jaroslaw

    2016-01-01

    Dosage compensation is the fundamental process by which gene expression from the male monosomic X chromosome and from the diploid set of autosomes is equalized. Various molecular mechanisms have evolved in different organisms to achieve this task. In Drosophila, genes on the male X chromosome are upregulated to the levels of expression from the two X chromosomes in females. To test whether a similar mechanism is operating in immature stages of Anopheles mosquitoes, we analyzed global gene expression in the Anopheles gambiae fourth instar larvae and pupae using high-coverage RNA-seq data. In pupae of both sexes, the median expression ratios of X-linked to autosomal genes (X:A) were close to 1.0, and within the ranges of expression ratios between the autosomal pairs, consistent with complete compensation. Gene-by-gene comparisons of expression in males and females revealed mild female bias, likely attributable to a deficit of male-biased X-linked genes. In larvae, male to female ratios of the X chromosome expression levels were more female biased than in pupae, suggesting that compensation may not be complete. No compensation mechanism appears to operate in male germline of early pupae. Confirmation of the existence of dosage compensation in A. gambiae lays the foundation for research into the components of dosage compensation machinery in this important vector species. PMID:26782933

  10. Molecular identification of chromosomal forms of Anopheles gambiae sensu stricto.

    PubMed

    Favia, G; Louis, C

    1999-09-01

    The Afrotropical malaria vectors Anopheles gambiae sensu stricto and An. arabiensis, responsible for more than 3/4 of the world Plasmodium falciparum inoculations, are members of the Anopheles gambiae complex, a group consisting of six sibling species. The nominal species (An. gambiae s.s.) is by far the most anthropophilic vector and its adaptation to man and his environment involves further ongoing speciation processes. This fact is shown by the existence of a number of incipient taxonomic units characterised by different chromosomal arrangements derived from the presence of polymorphic paracentric inversions. This speciation process is centered in West Africa, where five so-called 'chromosomal forms' have been described, designated with a non-Linnean nomenclature: Forest, Bissau, Savanna, Bamako, and Mopti. Studies on the distribution and the ecology of these incipient species have highlighted specific adaptations to eco-ethological parameters, which might reflect on their relative efficiency as malaria vectors. Cytogenetic analysis, in spite of some inherent difficulties, has proved to be a powerful tool for the identification of An. gambiae sibling species and the individual chromosomal forms. Yet, modern molecular tools are now available, providing alternative faster low-cost technologies, and we discuss here their relative merits.

  11. The Anopheles gambiae transcriptome - a turning point for malaria control.

    PubMed

    Domingos, A; Pinheiro-Silva, R; Couto, J; do Rosário, V; de la Fuente, J

    2017-04-01

    Mosquitoes are important vectors of several pathogens and thereby contribute to the spread of diseases, with social, economic and public health impacts. Amongst the approximately 450 species of Anopheles, about 60 are recognized as vectors of human malaria, the most important parasitic disease. In Africa, Anopheles gambiae is the main malaria vector mosquito. Current malaria control strategies are largely focused on drugs and vector control measures such as insecticides and bed-nets. Improvement of current, and the development of new, mosquito-targeted malaria control methods rely on a better understanding of mosquito vector biology. An organism's transcriptome is a reflection of its physiological state and transcriptomic analyses of different conditions that are relevant to mosquito vector competence can therefore yield important information. Transcriptomic analyses have contributed significant information on processes such as blood-feeding parasite-vector interaction, insecticide resistance, and tissue- and stage-specific gene regulation, thereby facilitating the path towards the development of new malaria control methods. Here, we discuss the main applications of transcriptomic analyses in An. gambiae that have led to a better understanding of mosquito vector competence.

  12. Larval Habitats Characterization and Species Composition of Anopheles Mosquitoes in Tunisia, with Particular Attention to Anopheles maculipennis Complex

    PubMed Central

    Tabbabi, Ahmed; Boussès, Philippe; Rhim, Adel; Brengues, Cécile; Daaboub, Jabeur; Ben-Alaya-Bouafif, Nissaf; Fontenille, Didier; Bouratbine, Aïda; Simard, Frédéric; Aoun, Karim

    2015-01-01

    In Tunisia, malaria transmission has been interrupted since 1980. However, the growing number of imported cases and the persistence of putative vectors stress the need for additional studies to assess the risk of malaria resurgence in the country. In this context, our aim was to update entomological data concerning Anopheles mosquitoes in Tunisia. From May to October of 2012, mosquito larval specimens were captured in 60 breeding sites throughout the country and identified at the species level using morphological keys. Environmental parameters of the larval habitats were recorded. Specimens belonging to the An. maculipennis complex were further identified to sibling species by the ribosomal deoxyribonucleic acid (rDNA)–internal transcribed spacer 2 (ITS2) polymerase chain reaction (PCR) technique. In total, 647 Anopheles larvae were collected from 25 habitats. Four species, including An. labranchiae, An. multicolor, An. sergentii, and An. algeriensis, were morphologically identified. rDNA-ITS2 PCR confirmed that An. labranchiae is the sole member of the An. maculipennis complex in Tunisia. An. labranchiae was collected throughout northern and central Tunisia, and it was highly associated with rural habitat, clear water, and sunlight areas. Larvae of An. multicolor and An. sergentii existed separately or together and were collected in southern Tunisia in similar types of breeding places. PMID:25561567

  13. Mass spectrometry identification of age-associated proteins from the malaria mosquitoes Anopheles gambiae s.s. and Anopheles stephensi.

    PubMed

    Sikulu, Maggy T; Monkman, James; Dave, Keyur A; Hastie, Marcus L; Dale, Patricia E; Kitching, Roger L; Killeen, Gerry F; Kay, Brian H; Gorman, Jeffry J; Hugo, Leon E

    2015-09-01

    This study investigated proteomic changes occurring in Anopheles gambiae and Anopheles stephensi during adult mosquito aging. These changes were evaluated using two-dimensional difference gel electrophoresis (2D-DIGE) and the identities of aging related proteins were determined using capillary high-pressure liquid chromatography (capHPLC) coupled with a linear ion-trap (LTQ)-Orbitrap XL hybrid mass spectrometry (MS). Here, we have described the techniques used to determine age associated proteomic changes occurring in heads and thoraces across three age groups; 1, 9 and 17 d old A. gambiae and 4 age groups; 1, 9, 17 and 34 d old A. stephensi. We have provided normalised spot volume raw data for all protein spots that were visible on 2D-DIGE images for both species and processed Orbitrap mass spectrometry data. For public access, mass spectrometry raw data are available via ProteomeXchange with identifier PXD002153. A detailed description of this study has been described elsewhere [1].

  14. Anopheles moucheti and Anopheles vinckei are candidate vectors of ape Plasmodium parasites, including Plasmodium praefalciparum in Gabon.

    PubMed

    Paupy, Christophe; Makanga, Boris; Ollomo, Benjamin; Rahola, Nil; Durand, Patrick; Magnus, Julie; Willaume, Eric; Renaud, François; Fontenille, Didier; Prugnolle, Franck

    2013-01-01

    During the last four years, knowledge about the diversity of Plasmodium species in African great apes has considerably increased. Several new species were described in chimpanzees and gorillas, and some species that were previously considered as strictly of human interest were found to be infecting African apes. The description in gorillas of P. praefalciparum, the closest relative of P. falciparum which is the main malignant agent of human malaria, definitively changed the way we understand the evolution and origin of P. falciparum. This parasite is now considered to have appeared recently, following a cross-species transfer from gorillas to humans. However, the Plasmodium vector mosquito species that have served as bridge between these two host species remain unknown. In order to identify the vectors that ensure ape Plasmodium transmission and evaluate the risk of transfer of these parasites to humans, we carried out a field study in Gabon to capture Anopheles in areas where wild and semi-wild ape populations live. We collected 1070 Anopheles females belonging to 15 species, among which An. carnevalei, An. moucheti and An. marshallii were the most common species. Using mtDNA-based PCR tools, we discovered that An. moucheti, a major human malaria vector in Central Africa, could also ensure the natural transmission of P. praefalciparum among great apes. We also showed that, together with An. vinckei, An. moucheti was infected with P. vivax-like parasites. An. moucheti constitutes, therefore, a major candidate for the transfer of Plasmodium parasites from apes to humans.

  15. Evidence of natural Wolbachia infections in field populations of Anopheles gambiae.

    PubMed

    Baldini, Francesco; Segata, Nicola; Pompon, Julien; Marcenac, Perrine; Shaw, W Robert; Dabiré, Roch K; Diabaté, Abdoulaye; Levashina, Elena A; Catteruccia, Flaminia

    2014-06-06

    Wolbachia are maternally transmitted intracellular bacteria that invade insect populations by manipulating their reproduction and immunity and thus limiting the spread of numerous human pathogens. Experimental Wolbachia infections can reduce Plasmodium numbers in Anopheles mosquitoes in the laboratory, however, natural Wolbachia infections in field anophelines have never been reported. Here we show evidence of Wolbachia infections in Anopheles gambiae in Burkina Faso, West Africa. Sequencing of the 16S rRNA gene identified Wolbachia sequences in both female and male germlines across two seasons, and determined that these sequences are vertically transmitted from mother to offspring. Whole-genome sequencing of positive samples suggests that the genetic material identified in An. gambiae belongs to a novel Wolbachia strain, related to but distinct from strains infecting other arthropods. The evidence of Wolbachia infections in natural Anopheles populations promotes further investigations on the possible use of natural Wolbachia-Anopheles associations to limit malaria transmission.

  16. Avoidance behavior to essential oils by Anopheles minimus, a malaria vector in Thailand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excito-repellency tests were used to characterize behavioral responses of laboratory colonized Anopheles minimus, a malaria vector in Thailand, using four essential oils, citronella (Cymbopogom nadus), hairy basil (Ocimum americanum), sweet basil (Ocimum basilicum), vetiver (Vetiveria zizanioides), ...

  17. Molecular comparison of topotypic specimens confirms Anopheles (Nyssorhynchus) dunhami Causey (Diptera: Culicidae) in the Colombian Amazon

    PubMed Central

    Ruiz, Freddy; Linton, Yvonne-Marie; Ponsonby, David J; Conn, Jan E; Herrera, Manuela; Quiñones, Martha L; Vélez, Iván D; Wilkerson, Richard C

    2015-01-01

    The presence of Anopheles (Nyssorhynchus) dunhami Causey in Colombia (Department of Amazonas) is confirmed for the first time through direct comparison of mtDNA cytochrome c oxidase I (COI) barcodes and nuclear rDNA second internal transcribed spacer (ITS2) sequences with topotypic specimens of An. dunhami from Tefé, Brazil. An. dunhami was identified through retrospective correlation of DNA sequences following misidentification as Anopheles nuneztovari s.l. using available morphological keys for Colombian mosquitoes. That An. dunhami occurs in Colombia and also possibly throughout the Amazon Basin, is of importance to vector control programs, as this non-vector species is morphologically similar to known malaria vectors including An. nuneztovari, Anopheles oswaldoi and Anopheles trinkae. Species identification of An. dunhami and differentiation from these closely related species are highly robust using either DNA ITS2 sequences or COI DNA barcode. DNA methods are advocated for future differentiation of these often sympatric taxa in South America. PMID:21120360

  18. Salivary Polytene Chromosome Map of Anopheles darlingi, the Main Vector of Neotropical Malaria

    PubMed Central

    Rafael, Míriam S.; Rohde, Cláudia; Bridi, Letícia C.; da Silva Valente Gaiesky, Vera Lúcia; Tadei, Wanderli P.

    2010-01-01

    New photomap of Anopheles (Nyssorhynchus) darlingi Root, 1926, is described for a population from Guajará-Mirim, State of Rondonia, Brazil. The number of sections in the previous A. darlingi reference map was maintained and new subsections were added to the five chromosome arms. Breakage points of paracentric inversions had been previously incorporated into the photomap of this species. An additional inversion is reported, called 3Lc, totaling 14 inversions in the A. darlingi chromosome arms. The proposed photomap is potentially useful for further evolutionary studies in addition to physical and in silico chromosome mapping using A. darlingi genomic and transcriptome sequences. Furthermore, in our attempt to compare sections of the 2R chromosome arm of A. darlingi with Anopheles funestus, Anopheles stephensi, and Anopheles gambiae, we found great differences in the arrangement of the polytene chromosome bands, which are consistent with the known phylogenetic divergence of these species. PMID:20682862

  19. Mosquitoes of Anopheles hyrcanus (Diptera, Culicidae) Group: Species Diagnostic and Phylogenetic Relationships

    PubMed Central

    Khrabrova, Natalia V.; Andreeva, Yulia V.; Sibataev, Anuarbek K.; Alekseeva, Svetlana S.; Esenbekova, Perizat A.

    2015-01-01

    Herein, we report the results of study of Anopheles species in Primorsk and Khabarovsk regions of Russia. Three species of the Anopheles hyrcanus group: An. kleini, An. pullus, and An. lesteri were identified by molecular taxonomic diagnostics for the first time in Russia. Surprisingly, An. sinensis, which earlier was considered the only species of Anopheles in Russian Far East, was not observed. We analyzed nucleotide variation in the 610-bp fragment of the 5′ end of the cytochrome c oxidase subunit I (COI) region. All species possessed a distinctive set of COI sequences. A maximum likelihood phylogenetic tree was constructed for members of the hyrcanus group. The examined Anopheles hyrcanus group members could be divided into two major subgroups: subgroup 1 (An. hyrcanus and An. pullus) and subgroup 2 (An. sinensis, An. kleini, and An. lesteri), which were found to be monophyletic. PMID:26149867

  20. Bionomics of Anopheles (Diptera: Culicidae) in a malaria endemic region of Sungai Nyamuk Village, Sebatik Island - North Kalimantan, Indonesia.

    PubMed

    Sugiarto; Hadi, Upik Kesumawati; Soviana, Susi; Hakim, Lukman

    2017-03-14

    The bionomics of Anopheles was investigated in coastal Sungai Nyamuk Village, Nunukan District, North Kalimantan Province from August 2010 to January 2012. Mosquitoes were captured using human landing collections. A total of 5,103 Anopheles mosquitoes comprising 11 species were caught and 2,259 adult parous females were tested by ELISA for Plasmodium antigen. Anopheles vagus, An. sundaicus and An. subpictus were the most abundant species caught. Overall, Anopheles vagus were zoophilic and exophagic, but there was variation between species. Anopheles sundaicus and An. subpictus were anthropophilic and endophagic. Anopheles peditaeniatus and An. sundaicus collected biting humans outdoors were positive for P. falciparum protein and were incriminated as the likely vectors of malaria in Sungai Nyamuk Village. This research also showed that malaria transmission in Sungai Nyamuk Village occurred outdoors. Residual house spraying therefore would not protect the human population from vector contact, so that combination use of long lasting nets and personel protection is needed.

  1. [Detection of Anopheles artemievi Gordeev et al. (Diptera, Culicidae) in Turkmenistan].

    PubMed

    Zvantsov, A B; Rozyev, K; Gordeev, M I; Goriacheva, I I; Khemzaev, Kh; Ezhov, M N

    2010-01-01

    Anopheles artemievi (a member of An. maculipennis complex species) described from the Transfergana region (South Kyrgyzstan) in 2004 was first found in the Lebap veloyat (Eastern Turkmenistan). A single larva of this species was collected together with An. superpictus in the irrigation channel of a rice field. Species affiliation has been proven by a polymerase chain reaction-restriction fragment length polymorphism method. This species is to be included into a list of Anopheles species of Turkmenistan.

  2. Mathematical Modeling of Sterile Insect Technology for Control of Anopheles Mosquito

    NASA Astrophysics Data System (ADS)

    Anguelov, R.; Dumont, Y.; Lubuma, J.

    2011-11-01

    Sterile Insect Technology (SIT) is a nonpolluting method of insect control that relies on the release of sterile males. We study the effectiveness of the application of SIT for control of Anopheles mosquito via mathematical modeling. The theoretical analysis of the mathematical model as a dynamical system leads to the formulation of possible strategies for control of the Anopheles mosquito, also illustrated by numerical simulations.

  3. Advances in the study of Anopheles funestus, a major vector of malaria in Africa.

    PubMed

    Coetzee, M; Fontenille, D

    2004-07-01

    The recent literature on cytogenetic and molecular studies of Anopheles funestus, a major vector of malaria in Africa, is reviewed. Molecular data from West and Central Africa suggest a new species in the group closely allied to Anopheles rivulorum. Cytogenetic and molecular studies of populations from West, Central, East and southern Africa indicate considerable genetic structuring within An. funestus itself, which may well restrict the spread of pyrethroid resistance that has been demonstrated in southern Africa.

  4. Identification and Characterization of Two Novel RNA Viruses from Anopheles gambiae Species Complex Mosquitoes

    PubMed Central

    Carissimo, Guillaume; Eiglmeier, Karin; Reveillaud, Julie; Holm, Inge; Diallo, Mawlouth; Diallo, Diawo; Vantaux, Amélie; Kim, Saorin; Ménard, Didier; Siv, Sovannaroth; Belda, Eugeni; Bischoff, Emmanuel; Antoniewski, Christophe; Vernick, Kenneth D.

    2016-01-01

    Mosquitoes of the Anopheles gambiae complex display strong preference for human bloodmeals and are major malaria vectors in Africa. However, their interaction with viruses or role in arbovirus transmission during epidemics has been little examined, with the exception of O’nyong-nyong virus, closely related to Chikungunya virus. Deep-sequencing has revealed different RNA viruses in natural insect viromes, but none have been previously described in the Anopheles gambiae species complex. Here, we describe two novel insect RNA viruses, a Dicistrovirus and a Cypovirus, found in laboratory colonies of An. gambiae taxa using small-RNA deep sequencing. Sequence analysis was done with Metavisitor, an open-source bioinformatic pipeline for virus discovery and de novo genome assembly. Wild-collected Anopheles from Senegal and Cambodia were positive for the Dicistrovirus and Cypovirus, displaying high sequence identity to the laboratory-derived virus. Thus, the Dicistrovirus (Anopheles C virus, AnCV) and Cypovirus (Anopheles Cypovirus, AnCPV) are components of the natural virome of at least some anopheline species. Their possible influence on mosquito immunity or transmission of other pathogens is unknown. These natural viruses could be developed as models for the study of Anopheles-RNA virus interactions in low security laboratory settings, in an analogous manner to the use of rodent malaria parasites for studies of mosquito anti-parasite immunity. PMID:27138938

  5. Species composition and natural infectivity of anthropophilic Anopheles (Diptera: Culicidae) in the states of Córdoba and Antioquia, Northwestern Colombia.

    PubMed

    Gutiérrez, Lina A; González, John J; Gómez, Giovan F; Castro, Martha I; Rosero, Doris A; Luckhart, Shirley; Conn, Jan E; Correa, Margarita M

    2009-12-01

    Malaria is a serious health problem in the states of Córdoba and Antioquia, Northwestern Colombia, where 64.4% of total Colombian cases were reported in 2007. Because little entomological information is available in this region, the aim of this work was to identify the Anopheles species composition and natural infectivity of mosquitoes distributed in seven localities with highest malaria transmission. A total of 1,768 Anopheles mosquitoes were collected using human landing catches from March 2007-July 2008. Ten species were identified; overall, Anopheles nuneztovari s.l. was the most widespread (62%) and showed the highest average human biting rates. There were six other species of the Nyssorhynchus subgenus: Anopheles albimanus (11.6%), Anopheles darlingi (9.8%), Anopheles braziliensis (6.6%), Anopheles triannulatus s.l. (3.5%), Anopheles albitarsis s.l. and Anopheles oswaldoi s.l. at < 1%; and three of the Anopheles subgenus: Anopheles punctimacula, Anopheles pseudopunctipennis s.l. and Anopheles neomaculipalpusat < 1% each. Two species from Córdoba, An. nuneztovari and An. darlingi, were found to be naturally infected by Plasmodium vivax VK247, as determined by ELISA and confirmed by nested PCR. All species were active indoors and outdoors. These results provide basic information for targeted vector control strategies in these localities.

  6. Scanning electron microscopic observations of Anopheles albimanus (Diptera: Culicidae) eggs.

    PubMed

    Rodriguez, M H; Chavez, B; Orozco, A; Loyola, E G; Martinez-Palomo, A

    1992-05-01

    To investigate the existence of subspecies of Anopheles albimanus Wiedeman in southern Mexico, the egg morphology of specimens obtained from several field populations and from insectary-adapted colonies of uniform pupal phenotype was examined. Scanning electron microscopic observations have shown that the eggs of An. albimanus are polymorphic in respect to the size and shape of their floats, but not in their ornamentation. Four types of eggs were found. Differences in the proportion of the various morphological types were statistically significant, although proportions of egg types were variable among individuals within the same population. These observations are suggestive of distinctive populations and warrant further studies using more sensitive methods to investigate sibling species in An. albimanus sensu lato.

  7. Phormidium animalis (Cyanobacteria: Oscillatoriaceae) supports larval development of Anopheles albimanus.

    PubMed

    Vázquez-Martínez, M Guadalupe; Rodríguez, Mario H; Arredondo-Jiménez, Juan I; Méndez-Sánchez, José D

    2003-06-01

    The capability of Phormidium animalis, a cyanobacterium commonly found in larval habitats of Anopheles albimanus in southern Mexico, to support larval development of this mosquito was investigated. First-stage larvae were reared under insectary conditions with P. animalis ad libitum and their development was compared with larvae fed with wheat germ. The time of pupation and adult mosquito size, assessed by wing length, were similar in both groups, but fewer adult mosquitoes were obtained from larvae fed with the cyanobacteria. Nevertheless, these observations indicate that P. animalis is ingested and assimilated by larval An. albimanus, making this cyanobacterium a good candidate for genetic engineering for the introduction of mosquitocidal toxins for malaria control in the region.

  8. Colombian Anopheles triannulatus (Diptera: Culicidae) Naturally Infected with Plasmodium spp.

    PubMed Central

    Rosero, Doris A.; Naranjo-Diaz, Nelson; Alvarez, Natalí; Cienfuegos, Astrid V.; Luckhart, Shirley

    2013-01-01

    The role of Anopheles triannulatus as a local vector has not yet been defined for malaria-endemic regions of Colombia. Therefore, the aim of this work was to detect An. triannulatus naturally infected with Plasmodium spp., as an approximation to determining its importance as malaria vector in the country. A total of 510 An. triannulatus were collected in six malaria-endemic localities of NW and SE Colombia from January 2009 to March 2011. In the NW, two specimens were naturally infected; one with Plasmodium vivax VK247, collected biting on humans and the other with Plasmodium falciparum, collected resting on cattle. In the SE, two specimens were positive for P. falciparum. Although these results show An. triannulatus naturally infected with Plasmodium, further studies are recommended to demonstrate the epidemiological importance of this species in malaria-endemic regions of Colombia. PMID:27335865

  9. Genetic Structure of Anopheles (Nyssorhynchus) marajoara (Diptera: Culicidae) in Colombia

    PubMed Central

    Brochero, Helena; Li, Cong; Wilkerson, Richard; Conn, Jan E.; Ruiz-García, Manuel

    2010-01-01

    Five Anopheles marajoara Galvão and Damasceno populations, representing diverse ecological conditions, were sampled throughout Colombia and analyzed using nine hypervariable DNA microsatellite loci. The overall genetic diversity (H = 0.58) was lower than that determined for some Brazilian populations using the same markers. The Caquetá population (Colombia) had the lowest gene diversity (H = 0.48), and it was the only population at Hardy–Weinberg equilibrium. Hardy–Weinberg disequilibrium in the remaining four populations was probably caused by the Wahlund effect. The assignment analyses showed two incompletely isolated gene pools separated by the Eastern Andean cordillera. However, other possible geographical barriers (rivers and other mountains) did not play any role in the moderate genetic heterogeneity found among these populations (FST = 0.069). These results are noteworthy, because this species is a putative malaria vector in Colombia. PMID:20810825

  10. Genetic structure of Anopheles (Nyssorhynchus) marajoara (Diptera: Culicidae) in Colombia.

    PubMed

    Brochero, Helena; Li, Cong; Wilkerson, Richard; Conn, Jan E; Ruiz-García, Manuel

    2010-09-01

    Five Anopheles marajoara Galvão and Damasceno populations, representing diverse ecological conditions, were sampled throughout Colombia and analyzed using nine hypervariable DNA microsatellite loci. The overall genetic diversity (H = 0.58) was lower than that determined for some Brazilian populations using the same markers. The Caquetá population (Colombia) had the lowest gene diversity (H = 0.48), and it was the only population at Hardy-Weinberg equilibrium. Hardy-Weinberg disequilibrium in the remaining four populations was probably caused by the Wahlund effect. The assignment analyses showed two incompletely isolated gene pools separated by the Eastern Andean cordillera. However, other possible geographical barriers (rivers and other mountains) did not play any role in the moderate genetic heterogeneity found among these populations (F(ST) = 0.069). These results are noteworthy, because this species is a putative malaria vector in Colombia.

  11. Laboratory colonization of Anopheles pseudopunctipennis (Diptera: Culicidae) without forced mating.

    PubMed

    Lardeux, Frédéric; Quispe, Vicente; Tejerina, Rosenka; Rodríguez, Roberto; Torrez, Libia; Bouchité, Bernard; Chávez, Tamara

    2007-08-01

    Anopheles pseudopunctipennis is one of the main malaria vectors in the Andean regions of South America. Few experimental data exist on this species because it is not very available in laboratories due to its eurygamic status that makes colony maintenance difficult. Indeed, individuals do not mate in the confined space of insectary cages. To avoid this problem, forced artificial mating can be used. However, this technique is time consuming, requires a well-trained technician, and is inadequate for easy mass production, which is sometimes necessary for certain experimental works. This study presents a technique based on exposure of adult mosquitoes to a blue stroboscopic light for 20 min during several nights, which encourages them to copulate naturally under laboratory conditions. After some generations, a self-free-mating strain was obtained. The technique is simple, inexpensive and is probably effective whatever the An. pseudopunctipennis strain considered.

  12. Organization of olfactory centres in the malaria mosquito Anopheles gambiae

    PubMed Central

    Riabinina, Olena; Task, Darya; Marr, Elizabeth; Lin, Chun-Chieh; Alford, Robert; O'Brochta, David A.; Potter, Christopher J.

    2016-01-01

    Mosquitoes are vectors for multiple infectious human diseases and use a variety of sensory cues (olfactory, temperature, humidity and visual) to locate a human host. A comprehensive understanding of the circuitry underlying sensory signalling in the mosquito brain is lacking. Here we used the Q-system of binary gene expression to develop transgenic lines of Anopheles gambiae in which olfactory receptor neurons expressing the odorant receptor co-receptor (Orco) gene are labelled with GFP. These neurons project from the antennae and maxillary palps to the antennal lobe (AL) and from the labella on the proboscis to the suboesophageal zone (SEZ), suggesting integration of olfactory and gustatory signals occurs in this brain region. We present detailed anatomical maps of olfactory innervations in the AL and the SEZ, identifying glomeruli that may respond to human body odours or carbon dioxide. Our results pave the way for anatomical and functional neurogenetic studies of sensory processing in mosquitoes. PMID:27694947

  13. Viral paratransgenesis in the malaria vector Anopheles gambiae.

    PubMed

    Ren, Xiaoxia; Hoiczyk, Egbert; Rasgon, Jason L

    2008-08-22

    Paratransgenesis, the genetic manipulation of insect symbiotic microorganisms, is being considered as a potential method to control vector-borne diseases such as malaria. The feasibility of paratransgenic malaria control has been hampered by the lack of candidate symbiotic microorganisms for the major vector Anopheles gambiae. In other systems, densonucleosis viruses (DNVs) are attractive agents for viral paratransgenesis because they infect important vector insects, can be genetically manipulated and are transmitted to subsequent generations. However, An. gambiae has been shown to be refractory to DNV dissemination. We discovered, cloned and characterized the first known DNV (AgDNV) capable of infection and dissemination in An. gambiae. We developed a flexible AgDNV-based expression vector to express any gene of interest in An. gambiae using a two-plasmid helper-transducer system. To demonstrate proof-of-concept of the viral paratransgenesis strategy, we used this system to transduce expression of an exogenous gene (enhanced green fluorescent protein; EGFP) in An. gambiae mosquitoes. Wild-type and EGFP-transducing AgDNV virions were highly infectious to An. gambiae larvae, disseminated to and expressed EGFP in epidemiologically relevant adult tissues such as midgut, fat body and ovaries and were transmitted to subsequent mosquito generations. These proof-of-principle data suggest that AgDNV could be used as part of a paratransgenic malaria control strategy by transduction of anti-Plasmodium peptides or insect-specific toxins in Anopheles mosquitoes. AgDNV will also be extremely valuable as an effective and easy-to-use laboratory tool for transient gene expression or RNAi in An. gambiae.

  14. Malaria vectorial capacity of a population of Anopheles gambiae

    PubMed Central

    Garrett-Jones, C.; Shidrawi, G. R.

    1969-01-01

    In order to assess the factors of malaria vectorial capacity and the daily reproduction rate, separate consideration is given to data from Kankiya, Northern Nigeria, concerning the incidence of vector—man contact (the man-biting rate), the vector's expectation of infective life, as reflected by the proportion of parous mosquitos under certain conditions, and the vector's man-biting habit, comprising the frequency of feeding and the human blood index. The main difficulty in the assessment of each of these factors was shown to be that of representative and adequate sampling, especially in a sprayed area. In order to compensate for deficiencies in the Kankiya data, especially with regard to the daily and cyclic survival-rates, the gonotrophic cycle and the effective sporogonic period, more complete published data on an Anopheles gambiae population in East Africa were examined, and extrapolations were made from these data in spite of the consequential risks involved. The results of the analysis show that the spraying of an area with DDT reduced the malaria vectorial capacity of Anopheles gambiae sp. B (the main vector of Plasmodium falciparum in the area) by an over-all factor of about 23 times. Nevertheless the basic reproduction rate of the disease is estimated to have averaged slightly over 20 in the sprayed area during the 6 months of the main transmission season. This is consistent with an observed recovery in the parasite rate, which had been reduced to a very low level by regular mass drug administration through the preceding dry season. The analysis was a tentative exercise in “epidemiological entomology” and it is suggested that in the postgraduate teaching of tropical hygiene, the epidemiological approach to entomology should be preferred to the classical morphological-bionomical approach. PMID:5306719

  15. Draft Genomes of Anopheles cracens and Anopheles maculatus: Comparison of Simian Malaria and Human Malaria Vectors in Peninsular Malaysia.

    PubMed

    Lau, Yee-Ling; Lee, Wenn-Chyau; Chen, Junhui; Zhong, Zhen; Jian, Jianbo; Amir, Amirah; Cheong, Fei-Wen; Sum, Jia-Siang; Fong, Mun-Yik

    2016-01-01

    Anopheles cracens has been incriminated as the vector of human knowlesi malaria in peninsular Malaysia. Besides, it is a good laboratory vector of Plasmodium falciparum and P. vivax. The distribution of An. cracens overlaps with that of An. maculatus, the human malaria vector in peninsular Malaysia that seems to be refractory to P. knowlesi infection in natural settings. Whole genome sequencing was performed on An. cracens and An. maculatus collected here. The draft genome of An. cracens was 395 Mb in size whereas the size of An. maculatus draft genome was 499 Mb. Comparison with the published Malaysian An. maculatus genome suggested the An. maculatus specimen used in this study as a different geographical race. Comparative analyses highlighted the similarities and differences between An. cracens and An. maculatus, providing new insights into their biological behavior and characteristics.

  16. Draft Genomes of Anopheles cracens and Anopheles maculatus: Comparison of Simian Malaria and Human Malaria Vectors in Peninsular Malaysia

    PubMed Central

    Chen, Junhui; Zhong, Zhen; Jian, Jianbo; Amir, Amirah; Cheong, Fei-Wen; Sum, Jia-Siang; Fong, Mun-Yik

    2016-01-01

    Anopheles cracens has been incriminated as the vector of human knowlesi malaria in peninsular Malaysia. Besides, it is a good laboratory vector of Plasmodium falciparum and P. vivax. The distribution of An. cracens overlaps with that of An. maculatus, the human malaria vector in peninsular Malaysia that seems to be refractory to P. knowlesi infection in natural settings. Whole genome sequencing was performed on An. cracens and An. maculatus collected here. The draft genome of An. cracens was 395 Mb in size whereas the size of An. maculatus draft genome was 499 Mb. Comparison with the published Malaysian An. maculatus genome suggested the An. maculatus specimen used in this study as a different geographical race. Comparative analyses highlighted the similarities and differences between An. cracens and An. maculatus, providing new insights into their biological behavior and characteristics. PMID:27347683

  17. Rapid discrimination between Anopheles gambiae s.s. and Anopheles arabiensis by High-Resolution Melt (HRM) analysis.

    PubMed

    Zianni, Michael R; Nikbakhtzadeh, Mahmood R; Jackson, Bryan T; Panescu, Jenny; Foster, Woodbridge A

    2013-04-01

    There is a need for more cost-effective options to more accurately discriminate among members of the Anopheles gambiae complex, particularly An. gambiae and Anopheles arabiensis. These species are morphologically indistinguishable in the adult stage, have overlapping distributions, but are behaviorally and ecologically different, yet both are efficient vectors of malaria in equatorial Africa. The method described here, High-Resolution Melt (HRM) analysis, takes advantage of minute differences in DNA melting characteristics, depending on the number of incongruent single nucleotide polymorphisms in an intragenic spacer region of the X-chromosome-based ribosomal DNA. The two species in question differ by an average of 13 single-nucleotide polymorphisms giving widely divergent melting curves. A real-time PCR system, Bio-Rad CFX96, was used in combination with a dsDNA-specific dye, EvaGreen, to detect and measure the melting properties of the amplicon generated from leg-extracted DNA of selected mosquitoes. Results with seven individuals from pure colonies of known species, as well as 10 field-captured individuals unambiguously identified by DNA sequencing, demonstrated that the method provided a high level of accuracy. The method was used to identify 86 field mosquitoes through the assignment of each to the two common clusters with a high degree of certainty. Each cluster was defined by individuals from pure colonies. HRM analysis is simpler to use than most other methods and provides comparable or more accurate discrimination between the two sibling species but requires a specialized melt-analysis instrument and software.

  18. Use of DNA barcoding to distinguish the malaria vector Anopheles neivai in Colombia.

    PubMed

    López-Rubio, Andrés; Suaza-Vasco, Juan; Marcet, Paula L; Ruíz-Molina, Natalia; Cáceres, Lorenzo; Porter, Charles; Uribe, Sandra

    2016-10-17

    A reference 535 bp barcode sequence from a fragment of the mitochondrial gene cytochrome oxidase I (COI), acquired from specimens of An. neivai Howard, Dyar & Knab, 1913 from its type locality in Panama, was used as a tool for distinguishing this species from others in the subgenus Kerteszia. Comparisons with corresponding regions of COI between An. neivai and other species in the subgenus (An. bellator Dyar & Knab 1906, An. homunculus Komp 1937, An cruzii Dyar & Knab, 1908 and An. laneanus Corrêa & Cerqueira, 1944) produced K2P genetic distances of 8.3-12.6%, values well above those associated with intraspecific variation. In contrast, genetic distances among 55 specimens from five municipalities in the Colombian Pacific coastal state of Chocó were all within the range of 0-2.5%, with an optimized barcode threshold of 1.3%, the limit for unambiguous differentiation of An. neivai. Among specimens from the Chocó region, 18 haplotypes were detected, two of which were widely distributed over the municipalities sampled. The barcode sequence permits discrimination of An. neivai from sympatric species and indicates genetic variability within the species; aspects key to malaria surveillance and control as well as defining geographic distribution and dispersion patterns.

  19. Use of DNA barcoding to distinguish the malaria vector Anopheles neivai in Colombia

    PubMed Central

    LÓPEZ-RUBIO, ANDRÉS; SUAZA-VASCO, JUAN; MARCET, PAULA L; RUÍZ-MOLINA, NATALIA; CÁCERES, LORENZO; PORTER, CHARLES; URIBE, SANDRA

    2016-01-01

    A reference 535 bp barcode sequence from a fragment of the mitochondrial gene cytochrome oxidase I (COI), acquired from specimens of An. neivai Howard, Dyar & Knab, 1913 from its type locality in Panama, was used as a tool for distinguishing this species from others in the subgenus Kerteszia. Comparisons with corresponding regions of COI between An. neivai and other species in the subgenus (An. bellator Dyar & Knab 1906, An. homunculus Komp 1937, An cruzii Dyar & Knab, 1908 and An. laneanus Corrêa & Cerqueira, 1944) produced K2P genetic distances of 8.3–12.6%, values well above those associated with intraspecific variation. In contrast, genetic distances among 55 specimens from five municipalities in the Colombian Pacific coastal state of Chocó were all within the range of 0–2.5%, with an optimized barcode threshold of 1.3%, the limit for unambiguous differentiation of An. neivai. Among specimens from the Chocó region, 18 haplotypes were detected, two of which were widely distributed over the municipalities sampled. The barcode sequence permits discrimination of An. neivai from sympatric species and indicates genetic variability within the species; aspects key to malaria surveillance and control as well as defining geographic distribution and dispersion patterns. PMID:27811749

  20. Evaluating preservation methods for identifying Anopheles gambiae s.s. and Anopheles arabiensis complex mosquitoes species using near infra-red spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Near infra-red spectroscopy (NIRS) has been successfully used on fresh and RNAlater® preserved Anopheles gambiae complex to identify sibling species and age. No preservation methods other than RNAlater® have been tested to preserve mosquitoes for species identification using NIRS. However, RNAlater®...

  1. Molecular Confirmation of Anopheles (Anopheles) lesteri from the Republic of South Korea and its Genetic Identity with An. (Ano.) anthropophagus from China (Diptera: Culicidae)

    DTIC Science & Technology

    2003-12-08

    genus Anopheles (Beebe et al. 1999; Fritz 1998; Marinucci et al. 1999; Paskewitz et al. 1993; Wilkerson et al. In press). Morphological...Control Association, 16, 189- 198. Marinucci , M., Romi, R., Mancini, P., Di, L.M. & Severini, C. (1999) Phylogenetic relationships of seven

  2. Draft Genome Sequence of Asaia sp. Strain SF2.1, an Important Member of the Microbiome of Anopheles Mosquitoes

    PubMed Central

    Shane, Jackie L.; Bongio, Nicholas J.; Favia, Guido

    2014-01-01

    Asaia spp. are abundant members of the microbiota of Anopheles mosquitoes, the principle vectors of malaria. Here, we report the draft genome sequence of Asaia sp. strain SF2.1. This strain is under development as a platform to deliver antimalarial peptides and proteins to adult female Anopheles mosquitoes. PMID:24407652

  3. A simple Chelex protocol for DNA extraction from Anopheles spp.

    PubMed

    Musapa, Mulenga; Kumwenda, Taida; Mkulama, Mtawa; Chishimba, Sandra; Norris, Douglas E; Thuma, Philip E; Mharakurwa, Sungano

    2013-01-09

    Endemic countries are increasingly adopting molecular tools for efficient typing, identification and surveillance against malaria parasites and vector mosquitoes, as an integral part of their control programs. For sustainable establishment of these accurate approaches in operations research to strengthen malaria control and elimination efforts, simple and affordable methods, with parsimonious reagent and equipment requirements are essential. Here we present a simple Chelex-based technique for extracting malaria parasite and vector DNA from field collected mosquito specimens. We morphologically identified 72 Anopheles gambiae sl. from 156 mosquitoes captured by pyrethrum spray catches in sleeping rooms of households within a 2,000 km(2) vicinity of the Malaria Institute at Macha. After dissection to separate the head and thorax from the abdomen for all 72 Anopheles gambiae sl. mosquitoes, the two sections were individually placed in 1.5 ml microcentrifuge tubes and submerged in 20 μl of deionized water. Using a sterile pipette tip, each mosquito section was separately homogenized to a uniform suspension in the deionized water. Of the ensuing homogenate from each mosquito section, 10 μl was retained while the other 10 μl was transferred to a separate autoclaved 1.5 ml tube. The separate aliquots were subjected to DNA extraction by either the simplified Chelex or the standard salting out extraction protocol(9,10). The salting out protocol is so-called and widely used because it employs high salt concentrations in lieu of hazardous organic solvents (such as phenol and chloroform) for the protein precipitation step during DNA extraction(9). Extracts were used as templates for PCR amplification using primers targeting arthropod mitochondrial nicotinamide adenine dinucleotide dehydrogenase (NADH) subunit 4 gene (ND4) to check DNA quality, a PCR for identification of Anopheles gambiae sibling species(10) and a nested PCR for typing of Plasmodium falciparum infection

  4. Anopheles gambiae Purine Nucleoside Phosphorylase: Catalysis, Structure, and Inhibition

    SciTech Connect

    Taylor,E.; Rinaldo-Matthis, A.; Li, L.; Ghanem, M.; Hazleton, K.; Cassera, M.; Almo, S.; Schramm, V.

    2007-01-01

    The purine salvage pathway of Anopheles gambiae, a mosquito that transmits malaria, has been identified in genome searches on the basis of sequence homology with characterized enzymes. Purine nucleoside phosphorylase (PNP) is a target for the development of therapeutic agents in humans and purine auxotrophs, including malarial parasites. The PNP from Anopheles gambiae (AgPNP) was expressed in Escherichia coli and compared to the PNPs from Homo sapiens (HsPNP) and Plasmodium falciparum (PfPNP). AgPNP has kcat values of 54 and 41 s-1 for 2'-deoxyinosine and inosine, its preferred substrates, and 1.0 s-1 for guanosine. However, the chemical step is fast for AgPNP at 226 s-1 for guanosine in pre-steady-state studies. 5'-Deaza-1'-aza-2'-deoxy-1'-(9-methylene)-Immucillin-H (DADMe-ImmH) is a transition-state mimic for a 2'-deoxyinosine ribocation with a fully dissociated N-ribosidic bond and is a slow-onset, tight-binding inhibitor with a dissociation constant of 3.5 pM. This is the tightest-binding inhibitor known for any PNP, with a remarkable Km/Ki* of 5.4 x 107, and is consistent with enzymatic transition state predictions of enhanced transition-state analogue binding in enzymes with enhanced catalytic efficiency. Deoxyguanosine is a weaker substrate than deoxyinosine, and DADMe-Immucillin-G is less tightly bound than DADMe-ImmH, with a dissociation constant of 23 pM for AgPNP as compared to 7 pM for HsPNP. The crystal structure of AgPNP was determined in complex with DADMe-ImmH and phosphate to a resolution of 2.2 Angstroms to reveal the differences in substrate and inhibitor specificity. The distance from the N1' cation to the phosphate O4 anion is shorter in the AgPNP{center_dot}DADMe-ImmH{center_dot}PO4 complex than in HsPNP{center_dot}DADMe-ImmH{center_dot}SO4, offering one explanation for the stronger inhibitory effect of DADMe-ImmH for AgPNP.

  5. Systematics of the Oswaldoi Complex (Anopheles, Nyssorhynchus) in South America

    PubMed Central

    2013-01-01

    Background Effective malaria control relies on accurate identification of those Anopheles mosquitoes responsible for the transmission of Plasmodium parasites. Anopheles oswaldoi s.l. has been incriminated as a malaria vector in Colombia and some localities in Brazil, but not ubiquitously throughout its Neotropical range. This evidence together with variable morphological characters and genetic differences supports that An. oswaldoi s.l. compromises a species complex. The recent fully integrated redescription of An. oswaldoi s.s. provides a solid taxonomic foundation from which to molecularly determine other members of the complex. Methods DNA sequences of the Second Internal Transcribed Spacer (ITS2 - rDNA) (n = 192) and the barcoding region of the Cytochrome Oxidase I gene (COI - mtDNA) (n = 110) were generated from 255 specimens of An. oswaldoi s.l. from 33 localities: Brazil (8 localities, including the lectotype series of An. oswaldoi), Ecuador (4), Colombia (17), Trinidad and Tobago (1), and Peru (3). COI sequences were analyzed employing the Kimura-two-parameter model (K2P), Bayesian analysis (MrBayes), Mixed Yule-Coalescent model (MYC, for delimitation of clusters) and TCS genealogies. Results Separate and combined analysis of the COI and ITS2 data sets unequivocally supported four separate species: two previously determined (An. oswaldoi s.s. and An. oswaldoi B) and two newly designated species in the Oswaldoi Complex (An. oswaldoi A and An. sp. nr. konderi). The COI intra- and inter-specific genetic distances for the four taxa were non-overlapping, averaging 0.012 (0.007 to 0.020) and 0.052 (0.038 to 0.064), respectively. The concurring four clusters delineated by MrBayes and MYC, and four independent TCS networks, strongly confirmed their separate species status. In addition, An. konderi of Sallum should be regarded as unique with respect to the above. Despite initially being included as an outgroup taxon, this species falls well within the

  6. Ivermectin inhibits the sporogony of Plasmodium falciparum in Anopheles gambiae

    PubMed Central

    2012-01-01

    Background When ingested in a blood meal, ivermectin has been shown to reduce the survivorship of Anopheles gambiae in the laboratory and field. Furthermore, ivermectin mass drug administrations in Senegal have been shown to reduce the proportion of Plasmodium falciparum-sporozoite-containing An. gambiae. This study addresses whether ivermectin inhibits sporogony of P. falciparum in An. gambiae. Methods Anophele gambiae s.s. G3 strain were fed two concentrations of ivermectin (LC25 and LC5) along with P. falciparum NF54 in human blood meals at staggered intervals. Mosquitoes ingested ivermectin concurrent with parasites (DPI 0), or at three (DPI 3), six (DPI 6), and nine (DPI 9) days post parasite ingestion, or three days prior (DPI −3) to parasite ingestion. Mosquitoes were dissected at seven, twelve or fourteen days post parasite ingestion and either oocyst or sporozoite prevalence was recorded. To determine if P. falciparum sporozoite-containing An. gambiae were more susceptible to ivermectin than uninfected controls, survivorship was recorded for mosquitoes which ingested P. falciparum or control blood meal on DPI 0 and then a second blood meal containing ivermectin (LC25) on DPI 14. Results Ivermectin (LC25) co-ingested (DPI 0) with parasites reduced the proportion of An. gambiae that developed oocysts (χ2 = 15.4842, P = 0.0002) and sporozoites (χ2 = 19.9643, P < 0.0001). Ivermectin (LC25) ingested DPI 6 (χ2 = 8.5103, P = 0.0044) and 9 (χ2 = 14.7998, P < 0.0001) reduced the proportion of An. gambiae that developed sporozoites but not when ingested DPI 3 (χ2 = 0.0113, P = 1). Ivermectin (LC5) co-ingested (DPI 0) with parasites did not reduce the proportion of An. gambiae that developed oocysts (χ2 = 4.2518, P = 0.0577) or sporozoites (χ2 = 2.3636, P = 0.1540), however, when ingested DPI −3 the proportion of An. gambiae that developed sporozoites was reduced (χ2 = 8.4806, P = 0.0047). Plasmodium falciparum infection significantly reduced the

  7. Bacterial Diversity Associated with Wild Caught Anopheles Mosquitoes from Dak Nong Province, Vietnam Using Culture and DNA Fingerprint

    PubMed Central

    Ngo, Chung Thuy; Aujoulat, Fabien; Veas, Francisco; Jumas-Bilak, Estelle; Manguin, Sylvie

    2015-01-01

    Background Microbiota of Anopheles midgut can modulate vector immunity and block Plasmodium development. Investigation on the bacterial biodiversity in Anopheles, and specifically on the identification of bacteria that might be used in malaria transmission blocking approaches, has been mainly conducted on malaria vectors of Africa. Vietnam is an endemic country for both malaria and Bancroftian filariasis whose parasitic agents can be transmitted by the same Anopheles species. No information on the microbiota of Anopheles mosquitoes in Vietnam was available previous to this study. Method The culture dependent approach, using different mediums, and culture independent (16S rRNA PCR – TTGE) method were used to investigate the bacterial biodiversity in the abdomen of 5 Anopheles species collected from Dak Nong Province, central-south Vietnam. Molecular methods, sequencing and phylogenetic analysis were used to characterize the microbiota. Results and Discussion The microbiota in wild-caught Anopheles was diverse with the presence of 47 bacterial OTUs belonging to 30 genera, including bacterial genera impacting Plasmodium development. The bacteria were affiliated with 4 phyla, Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria, the latter being the dominant phylum. Four bacterial genera are newly described in Anopheles mosquitoes including Coxiella, Yersinia, Xanthomonas, and Knoellia. The bacterial diversity per specimen was low ranging from 1 to 4. The results show the importance of pairing culture and fingerprint methods to better screen the bacterial community in Anopheles mosquitoes. Conclusion Sampled Anopheles species from central-south Vietnam contained a diverse bacterial microbiota that needs to be investigated further in order to develop new malaria control approaches. The combination of both culture and DNA fingerprint methods allowed a thorough and complementary screening of the bacterial community in Anopheles mosquitoes. PMID:25747513

  8. Determinants of Anopheles seasonal distribution patterns across a forest to periurban gradient near Iquitos, Peru.

    PubMed

    Reinbold-Wasson, Drew D; Sardelis, Michael R; Jones, James W; Watts, Douglas M; Fernandez, Roberto; Carbajal, Faustino; Pecor, James E; Calampa, Carlos; Klein, Terry A; Turell, Michael J

    2012-03-01

    As part of a field ecology study of arbovirus and malaria activity in the Amazon Basin, Loreto Department, Peru, we collected mosquitoes landing on humans at a forest site and inside and outside of residences and military barracks at periurban, rural, and village sites. We collected 11 Anopheles spp. from these four sites. An. darlingi, the principal malaria vector in the region, accounted for 98.7% of all Anopheles spp. collected at Puerto Almendra. Peaks in landing activity occurred during the December and April collection periods. However, the percent of sporozoite-positive Anopheles spp. was highest 1-2 months later, when landing activity decreased to approximately 10% of the peak activity periods. At all sites, peak landing activity occurred about 2 hours after sunset. These data provide a better understanding of the taxonomy, population density, and seasonal and habitat distribution of potential malaria vectors within the Amazon Basin region.

  9. Biology of Anopheles saperoi, an Endemic Species in Okinawajima, the Ryukyu Archipelago, Japan.

    PubMed

    Mannen, Kosuke; Toma, Takako; Minakawa, Noboru; Higa, Yukiko; Miyagi, Ichiro

    2016-03-01

    Biological studies of Anopheles saperoi were conducted using larval and adult mosquito collections in the northern part of Okinawajima of the Ryukyu Archipelago from June 2009 to July 2010. Anopheles saperoi was the most collected species in the northern Okinawajima, except Motobu Peninsula, where it was not collected. The southern distribution of An. saperoi was Sugita Stream, Nago City. Anopheles saperoi was collected throughout the year with reproduction (gonotrophic cycle) observed year-round. Immature densities varied for Hinna and Yona streams, and were negatively affected by precipitation patterns. Human attraction activity of females varied for by study area and collection time and was positively affected by temperature, but negatively by heavy rainfall. The greatest female human attraction activity was observed during 3:00-5:00 p.m., with peak at twilight. Parity rates varied from 23.1% to 83.3% throughout the year.

  10. Factors influencing infection and transmission of Anopheles gambiae densovirus (AgDNV) in mosquitoes

    PubMed Central

    2016-01-01

    Anopheles gambiae densovirus (AgDNV) is a potential microbial agent for paratransgenesis and gene transduction in An. gambiae, the major vector of human malaria in sub-Saharan Africa. Understanding the interaction between AgDNV and An. gambiae is critical for using AgDNV in a basic and applied manner for Anopheles gene manipulation. Here, we tested the effects of mosquito age, sex, blood feeding status, and potential for horizontal transmission using an enhanced green fluorescent protein (EGFP) reporter AgDNV system. Neither mosquito age at infection nor feeding regime affected viral titers. Female mosquitoes were more permissive to viral infection than males. Despite low viral titers, infected males were able to venereally transmit virus to females during mating, where the virus was localized with the transferred sperm in the spermathecae. These findings will be useful for designing AgDNV-based strategies to manipulate Anopheles gambiae. PMID:27867767

  11. Factors influencing infection and transmission of Anopheles gambiae densovirus (AgDNV) in mosquitoes.

    PubMed

    Barik, Tapan K; Suzuki, Yasutsugu; Rasgon, Jason L

    2016-01-01

    Anopheles gambiae densovirus (AgDNV) is a potential microbial agent for paratransgenesis and gene transduction in An. gambiae, the major vector of human malaria in sub-Saharan Africa. Understanding the interaction between AgDNV and An. gambiae is critical for using AgDNV in a basic and applied manner for Anopheles gene manipulation. Here, we tested the effects of mosquito age, sex, blood feeding status, and potential for horizontal transmission using an enhanced green fluorescent protein (EGFP) reporter AgDNV system. Neither mosquito age at infection nor feeding regime affected viral titers. Female mosquitoes were more permissive to viral infection than males. Despite low viral titers, infected males were able to venereally transmit virus to females during mating, where the virus was localized with the transferred sperm in the spermathecae. These findings will be useful for designing AgDNV-based strategies to manipulate Anopheles gambiae.

  12. [Anopheles funestus and rice agriculture in the Madagascar highlands].

    PubMed

    Marrama, L; Rajaonarivelo, E; Laventure, S; Rabarison, P

    1995-01-01

    An exhaustive study of the potential habitats of Anopheles funestus was led during 1992 in Ankazobe on the Plateau of Madagascar, 95 km northwest of the capital Tananarive. The rice fields provide more than 90% of the positive habitats versus less than 10% for the nonhuman biotopes. Larva are especially abundant on the surfaces of the rice during grain head formation and maturation. The dense vegetation coverage provides them with shade and protection against predators. After harvesting, the follows can be filled with water and wild vegetation, and then also provide an important share of the habitats. The rice fields are omnipresent on the Plateau where they supply the basis of local alimentation. A. funestus then constitutes a serious risk for all of the villages. The role of the rice fields as habitats for A. funestus has already been noted in Kenya but in West Africa the rice fields do not host this species, even if this species is very abundant in the other types of habitats.

  13. Exploring Anopheles gut bacteria for Plasmodium blocking activity

    PubMed Central

    Bahia, Ana C; Dong, Yuemei; Blumberg, Benjamin J; Mlambo, Godfree; Tripathi, Abhai; BenMarzouk-Hidalgo, Omar J; Chandra, Ramesh; Dimopoulos, George

    2014-01-01

    SUMMARY Malaria parasite transmission requires the successful development of Plasmodium gametocytes into flagellated microgametes upon mosquito blood ingestion, and the subsequent fertilization of microgametes and macrogametes for the development of motile zygotes, called ookinetes, which invade and transverse the Anopheles vector mosquito midgut at around 18-36 h after blood ingestion. Within the mosquito midgut, the malaria parasite has to withstand the mosquito's innate immune response and the detrimental effect of its commensal bacterial flora. We have assessed the midgut colonization capacity of 5 gut bacterial isolates from field-derived, and 2 from laboratory colony, mosquitoes and their effect on Plasmodium development in vivo and in vitro, along with their impact on mosquito survival. Some bacterial isolates activated the mosquito's immune system, affected the mosquito's life span, and were capable of blocking Plasmodium development. We have also shown that the ability of these bacteria to inhibit the parasites is likely to involve different mechanisms and factors. A Serratia marcescens isolate was particularly efficient in colonizing the mosquitoes’ gut, compromising mosquito survival, and inhibiting both sexual- and asexual-stage Plasmodium through secreted factors, thereby rendering it a potential candidate for the development of a malaria transmission intervention strategy. PMID:24428613

  14. Behavior and population structure of Anopheles darlingi in Colombia.

    PubMed

    Naranjo-Díaz, Nelson; Conn, Jan E; Correa, Margarita M

    2016-04-01

    Anopheles darlingi is a widely distributed and important malaria vector in Colombia. Biogeographical and ecological heterogeneity across the Colombian distribution led to the hypothesis of behavioral and genetic differentiation among A. darlingi populations. A total of 2017 A. darlingi specimens were collected during 222 h of sampling. This vector was the most abundant anopheline species in most of the localities sampled. Subdivision between samples collected west and east of the Andes was indicated by 1) mitochondrial COI and nuclear CAD sequences from NW-W and CE-S populations (COI ΦST=0.48761-0.81974, CAD FST=0.11319-0.21321), 2) a COI haplotype network, and 3) SAMOVA. Endo- and exophagy were detected in populations west of the Andes, whereas exophagy was evident in PTG, a locality east of the Andes. Isolation by resistance was significant for COI and explained 26% of the genetic differentiation. We suggest that at a macrogeographic scale, the Andes influence the differentiation of A. darlingi in Colombia and may drive divergence, and, at a microgeographic scale, ecological differences have a significant impact on structure. These data could constitute a baseline for the design of effective vector interventions, locality-specific for the east and similar for panmictic populations west of the Andes.

  15. Bionomics of sympatric chromosomal forms of Anopheles funestus (Diptera: Culicidae).

    PubMed

    Dia, Ibrahima; Sagnon, N'Fale; Guelbeogo, Moussa Wamdaogo; Diallo, Mawlouth

    2011-12-01

    Anopheles funestus is one of the major vectors of malaria in Africa. Cytogenetic studies conducted on populations from West Africa have shown variable degrees of polymorphism with a genetic structure leading to the description of two chromosomal forms called "Folonzo" and "Kiribina" that exhibit limited gene flow. Because studies on allopatric populations showed bionomical heterogeneities, the present study was undertaken during three consecutive years (2006, 2007, and 2008) in an area of sympatry in Senegal, in order to assess their bionomical characteristics and compare their epidemiologic role in malaria transmission. Overall, the two forms coexisted in the study area; the Kiribina form being more abundant and exhibiting higher biting rates. Based on an enzyme-linked immunosorbent assay, the anthropophilic rates were statistically comparable and were, respectively, 30.7% and 28.6% for Kiribina and Folonzo. Plasmodium falciparum circumsporozoite rates were also comparable and were 2.7% for Kiribina and 3.1% for Folonzo. Both forms were involved in malaria transmission; Kiribina being responsible for 68% of transmission. Thus, due to the limited gene flow between the two forms, the introduction of transgene for Plasmodium resistance in one of the two forms could be a disadvantage for the implementation of control strategies based on the use of Plasmodium-refractory genetically modified individuals. Nevertheless, it could represent an advantage limiting the insurgence of insecticide resistance gene spread between forms and should be taken into account for the implementation of control strategies.

  16. Biolistic techniques for transfection of mosquito embryos (Anopheles gambiae).

    PubMed

    Mialhe, E; Miller, L H

    1994-05-01

    To compensate for the extremely low rates of transformation by DNA microinjection into mosquito embryos of Anopheles gambiae, biolistic techniques were evaluated for introduction of DNA into large numbers of mosquito embryos. Biolistic experiments were first performed with a commercially available instrument intended for this purpose, according to the recommended procedure. The amount of DNA delivered was measured by the expression of luciferase under the control of the Drosophila heat shock protein (hsp) 70 promoter. Despite attempts to optimize biolistic parameters, the level of luciferase activity was low and highly variable. Two other methods of biolistic delivery of DNA-coated particles in aqueous suspension were then evaluated. One method used the gas explosion of the commercially available instrument (mentioned above) to drive an aqueous suspension of DNA-coated particles at high pressure. This method reproducibly increased the level of expression about 100-fold without greatly reducing embryo viability. Another method, which was recently described for plant transfection, uses lower pressure to deliver the aqueous suspension of DNA-coated particles. The level of expression of luciferase and the survival of embryos were equivalent to that obtained with the instrument modified for aqueous delivery of particles. Thus, both aqueous methods offer the advantages of reproducibly delivering more DNA to the embryos. Moreover, these methods could be suitable for delivering DNA mixed with proteins, such as restriction endonucleases and integrases, that may be destroyed by ethanol precipitation used in the standard PDS-1000/He method.

  17. Seasonal genetic partitioning in the neotropical malaria vector, Anopheles darlingi

    PubMed Central

    2014-01-01

    Background Anopheles darlingi is the main malaria mosquito vector in the Amazonia region. In spite of being considered a riverine, forest-dwelling species, this mosquito is becoming more abundant in peri-urban areas, increasing malaria risk. This has been associated with human-driven environmental changes such as deforestation. Methods Microsatellites were used to characterize A. darlingi from seven localities along the Madeira River, Rondônia (Brazil), collected in the early and late periods of the rainy season. Results Two genetically distinct subpopulations were detected: one (subpopulation A) was associated with the late rainfall period and seems to be ecologically closer to the typical forest A. darlingi; the other (subpopulation B) was associated with the early rainfall period and is probably more adapted to drier conditions by exploiting permanent anthropogenic breeding sites. Results suggest also a pattern of asymmetric introgression, with more subpopulation A alleles introgressed into subpopulation B. Both subpopulations (and admixed mosquitoes) presented similar malaria infection rates, highlighting the potential for perennial malaria transmission in the region. Conclusions The co-occurrence of two genetically distinct subpopulations of A. darlingi adapted to different periods of rainfall may promote a more perennial transmission of malaria throughout the year. These findings, in a context of strong environmental impact due to deforestation and dam construction, have serious implications for malaria epidemiology and control in the Amazonian region. PMID:24885508

  18. Characterisation of Species and Diversity of Anopheles gambiae Keele Colony

    PubMed Central

    McGeechan, Sion; Inch, Donald; Smart, Graeme; Richterová, Lenka; Mwangi, Jonathan M.

    2016-01-01

    Anopheles gambiae sensu stricto was recently reclassified as two species, An. coluzzii and An. gambiae s.s., in wild-caught mosquitoes, on the basis of the molecular form, denoted M or S, of a marker on the X chromosome. The An. gambiae Keele line is an outbred laboratory colony strain that was developed around 12 years ago by crosses between mosquitoes from 4 existing An. gambiae colonies. Laboratory colonies of mosquitoes often have limited genetic diversity because of small starting populations (founder effect) and subsequent fluctuations in colony size. Here we describe the characterisation of the chromosomal form(s) present in the Keele line, and investigate the diversity present in the colony using microsatellite markers on chromosome 3. We also characterise the large 2La inversion on chromosome 2. The results indicate that only the M-form of the chromosome X marker is present in the Keele colony, which was unexpected given that 3 of the 4 parent colonies were probably S-form. Levels of diversity were relatively high, as indicated by a mean number of microsatellite alleles of 6.25 across 4 microsatellites, in at least 25 mosquitoes. Both karyotypes of the inversion on chromosome 2 (2La/2L+a) were found to be present at approximately equal proportions. The Keele colony has a mixed M- and S-form origin, and in common with the PEST strain, we propose continuing to denote it as an An. gambiae s.s. line. PMID:28033418

  19. Transmission potential of Rickettsia felis infection by Anopheles gambiae mosquitoes

    PubMed Central

    Dieme, Constentin; Bechah, Yassina; Socolovschi, Cristina; Audoly, Gilles; Berenger, Jean-Michel; Faye, Ousmane; Raoult, Didier; Parola, Philippe

    2015-01-01

    A growing number of recent reports have implicated Rickettsia felis as a human pathogen, paralleling the increasing detection of R. felis in arthropod hosts across the globe, primarily in fleas. Here Anopheles gambiae mosquitoes, the primary malarial vectors in sub-Saharan Africa, were fed with either blood meal infected with R. felis or infected cellular media administered in membrane feeding systems. In addition, a group of mosquitoes was fed on R. felis-infected BALB/c mice. The acquisition and persistence of R. felis in mosquitoes was demonstrated by quantitative PCR detection of the bacteria up to day 15 postinfection. R. felis was detected in mosquito feces up to day 14. Furthermore, R. felis was visualized by immunofluorescence in salivary glands, in and around the gut, and in the ovaries, although no vertical transmission was observed. R. felis was also found in the cotton used for sucrose feeding after the mosquitoes were fed infected blood. Natural bites from R. felis-infected An. gambiae were able to cause transient rickettsemias in mice, indicating that this mosquito species has the potential to be a vector of R. felis infection. This is particularly important given the recent report of high prevalence of R. felis infection in patients with “fever of unknown origin” in malaria-endemic areas. PMID:26056256

  20. Plasmodium activates the innate immune response of Anopheles gambiae mosquitoes.

    PubMed Central

    Richman, A M; Dimopoulos, G; Seeley, D; Kafatos, F C

    1997-01-01

    Innate immune-related gene expression in the major disease vector mosquito Anopheles gambiae has been analyzed following infection by the malaria parasite, Plasmodium berghei. Substantially increased levels of mRNAs encoding the antibacterial peptide defensin and a putative Gram-negative bacteria-binding protein (GNBP) are observed 20-30 h after ingestion of an infected blood-meal, at a time which indicates that this induction is a response to parasite invasion of the midgut epithelium. The induction is dependent upon the ingestion of infective, sexual-stage parasites, and is not due to opportunistic co-penetration of resident gut micro-organisms into the hemocoel. The response is activated following infection both locally (in the midgut) and systemically (in remaining tissues, presumably fat body and/or hemocytes). The observation that Plasmodium can trigger a molecularly defined immune response in the vector constitutes an important advance in our understanding of parasite-vector interactions that are potentially involved in malaria transmission, and extends knowledge of the innate immune system of insects to encompass responses to protozoan parasites. PMID:9321391

  1. Forest malaria in Bangladesh. II. Transmission by Anopheles dirus.

    PubMed

    Rosenberg, R; Maheswary, N P

    1982-03-01

    Seasonal, holoendemic malaria transmission in a small, isolated forest community was studied by doing outdoor and indoor all-night man-biting catches over 21 consecutive months. More than 3.8% of Anopheles dirus (=An. balabacensis s.l.), the most frequently caught anopheline, were infective. One An. annularis was also infective. Transmission occurred only during the 7-month monsoon. In the absence of DDT, An. dirus bit with equal frequency indoors and outdoors. When DDT was present in dwellings, fewer females fed indoors and they fed earlier. Feeding pattern was influenced by the phase of the moon: peak outdoors feeding was sharpest and earliest at first quarter and came later as the moon rose later. An average 31% of biting An. dirus lived long enough to reach infectivity of P. falciparum. Although fewer than 10 females fed per man per night, a resident could have received more than 100 infective bites in 2 years. Correlation between actual and calculated rates of gametocytemia were poorest in months when calculated survival rates of mosquitoes were most suspect.

  2. Inactivation of Anopheles gambiae Glutathione Transferase ε2 by Epiphyllocoumarin

    PubMed Central

    Marimo, Patience; Hayeshi, Rose; Mukanganyama, Stanley

    2016-01-01

    Glutathione transferases (GSTs) are part of a major family of detoxifying enzymes that can catalyze the reductive dehydrochlorination of dichlorodiphenyltrichloroethane (DDT). The delta and epsilon classes of insect GSTs have been implicated in conferring resistance to this insecticide. In this study, the inactivation of Anopheles gambiae GSTε2 by epiphyllocoumarin (Tral 1) was investigated. Recombinant AgGSTε2 was expressed in Escherichia coli cells containing a pET3a-AGSTε2 plasmid and purified by affinity chromatography. Tral 1 was shown to inactivate GSTε2 both in a time-dependent manner and in a concentration-dependent manner. The half-life of GSTε2 in the presence of 25 μM ethacrynic acid (ETA) was 22 minutes and with Tral 1 was 30 minutes, indicating that Tral 1 was not as efficient as ETA as an inactivator. The inactivation parameters kinact and KI were found to be 0.020 ± 0.001 min−1 and 7.5 ± 2.1 μM, respectively, after 90 minutes of incubation. Inactivation of GSTε2 by Tral 1 implies that Tral 1 covalently binds to this enzyme in vitro and would be expected to exhibit time-dependent effects on the enzyme in vivo. Tral 1, therefore, would produce irreversible effects when used together with dichlorodiphenyltrichloroethane (DDT) in malaria control programmes where resistance is mediated by GSTs. PMID:26925266

  3. Resistance Mechanisms of Anopheles stephensi (Diptera: Culicidae) to Temephos

    PubMed Central

    Soltani, Aboozar; Vatandoost, Hassan; Oshaghi, Mohammad Ali; Ravasan, Naseh Maleki; Enayati, Ahmad Ali; Asgarian, Fatemeh

    2015-01-01

    Background: Anopheles stephensi is a sub-tropical species and has been considered as one of the most important vector of human malaria throughout the Middle East and South Asian region including the malarious areas of southern Iran. Current reports confirmed An. stephensi resistance to temephos in Oman and India. However, there is no comprehensive research on mechanisms of temephos resistance in An. stephensi in the literature. This study was designed in order to clarify the enzymatic and molecular mechanisms of temephos resistance in this species. Methods: Profile activities of α- and ß-esterases, mixed function oxidase (MFO), glutathione-S-transferase (GST), insensitive acetylcholinesterase, and para-nitrophenyl acetate (PNPA)-esterase enzymes were tested for An. stephensi strain with resistance ratio of 15.82 to temephos in comparison with susceptible strain. Results: Results showed that the mean activity of α-EST, GST and AChE enzymes were classified as altered indicating metabolic mechanisms have considerable role in resistance of An. stephensi to temephos. Molecular study using PCR-RFLP method to trace the G119S mutation in ACE-1 gene showed lack of the mutation responsible for organophosphate insecticide resistance in the temephos-selected strain of An. stephensi. Conclusion: This study showed that the altered enzymes but not targets site insensitivity of ACE-1 are responsible for temephos resistance in An. stephensi in south of Iran. PMID:26114145

  4. The evolutionary divergence of STAT transcription factor in different Anopheles species.

    PubMed

    Gupta, Kuldeep; Dhawan, Rini; Kajla, Mithilesh; Misra, Tripti; Kumar, Sanjeev; Gupta, Lalita

    2017-01-05

    Anopheles mosquito transmits Plasmodium, the malaria causing parasite. Different species of Anopheles mosquito dominate in a particular geographical location and are capable of transmitting specific strains of Plasmodium. It is important to understand the biology of different anophelines to control the parasite transmission. STAT is an evolutionary conserved transcription factor that regulates the parasite development in African malaria vector Anopheles gambiae. Unlike Drosophila and Aedes aegypti, where a single STAT gene plays an important role in immunity, An. gambiae contains one evolutionary conserved STAT-A and another retro-duplicated, introns-less STAT-B gene. To find out whether other species of Anopheles also have two STATs, the available genomic data of different anophelines were used to annotate their STATs through in silico analyses. Our results revealed that Indian malaria vector An. stephensi genome contains two STATs, AsSTAT-A and AsSTAT-B genes. These genes were cloned and confirmed by sequencing. Both AsSTATs were found to be expressed in different development stages of mosquito. However, the relative mRNA levels of evolutionary conserved AsSTAT-A gene were always higher than the retroduplicated AsSTAT-B gene. STAT pathway was activated upon Plasmodium berghei infection, indicated its role in immunity. Furthermore, comparative in silico analysis of eighteen Anopheles species revealed that five species: An. sinensis, An. albimanus, An. darlingi, An. dirus andAn. farauti do not contain STAT-B gene in their genome. Interestingly, thirteen species of the subgenus Anopheles and Cellia that contain both STATs were also mutually diverged. This consequence leads to sequence variability in some significant protein motifs within the STAT-B genes. Phylogenetic analyses indicated that an independent, lineage-specific duplication occurred in the subgenus Cellia after the diversification of series Neomyzomyia from its last common ancestor. In An. atroparvus

  5. Wolbachia infections in Anopheles gambiae cells: transcriptomic characterization of a novel host-symbiont interaction.

    PubMed

    Hughes, Grant L; Ren, Xiaoxia; Ramirez, Jose L; Sakamoto, Joyce M; Bailey, Jason A; Jedlicka, Anne E; Rasgon, Jason L

    2011-02-01

    The endosymbiotic bacterium Wolbachia is being investigated as a potential control agent in several important vector insect species. Recent studies have shown that Wolbachia can protect the insect host against a wide variety of pathogens, resulting in reduced transmission of parasites and viruses. It has been proposed that compromised vector competence of Wolbachia-infected insects is due to up-regulation of the host innate immune system or metabolic competition. Anopheles mosquitoes, which transmit human malaria parasites, have never been found to harbor Wolbachia in nature. While transient somatic infections can be established in Anopheles, no stable artificially-transinfected Anopheles line has been developed despite numerous attempts. However, cultured Anopheles cells can be stably infected with multiple Wolbachia strains such as wAlbB from Aedes albopictus, wRi from Drosophila simulans and wMelPop from Drosophila melanogaster. Infected cell lines provide an amenable system to investigate Wolbachia-Anopheles interactions in the absence of an infected mosquito strain. We used Affymetrix GeneChip microarrays to investigate the effect of wAlbB and wRi infection on the transcriptome of cultured Anopheles Sua5B cells, and for a subset of genes used quantitative PCR to validate results in somatically-infected Anopheles mosquitoes. Wolbachia infection had a dramatic strain-specific effect on gene expression in this cell line, with almost 700 genes in total regulated representing a diverse array of functional classes. Very strikingly, infection resulted in a significant down-regulation of many immune, stress and detoxification-related transcripts. This is in stark contrast to the induction of immune genes observed in other insect hosts. We also identified genes that may be potentially involved in Wolbachia-induced reproductive and pathogenic phenotypes. Somatically-infected mosquitoes had similar responses to cultured cells. The data show that Wolbachia has a profound

  6. Factors associated with distribution of Anopheles aquasalis and Anopheles oswaldoi (Diptera: Culicidae) in a malarious area, northeastern Venezuela.

    PubMed

    Grillet, M E

    2000-03-01

    Spatial and temporal abundance patterns of anopheline larvae and their relationships with wetland conditions were studied in an endemic malaria area in northeastern Venezuela, where Anopheles aquasalis Curry is the main vector. Larvae were sampled over a 2-yr period in 7 wetland types (brackish and freshwater herbaceous swamps, mangrove swamps, freshwater ponds, clear-cut marsh forests, small irrigation canals, and swamp forests), covering 3 environmental gradients (salinity, aquatic vegetation, and habitat permanence). Twelve variable were quantified to describe each habitat. Two species of anophelines were collected. An. aquasalis was the species with the widest distribution, and its highest abundance was in the seasonal brackish mangrove habitat during the rainy season. An. oswaldoi Peryassu was rarely encountered, but was mainly associated with the dry season and with the permanent fresh water wetlands (such as ponds). Principal components and correlation analyses revealed that the physicochemical (salinity, dissolved oxygen) variables of the wetland were associated most strongly with the spatial distribution of both species. Variations in salinity were strongly associated with the abundance of An. aquasalis. Both the occurrence and abundance of An. oswaldoi were most closely correlated with dissolved oxygen. Changes in seasonal abundance of both species were associated with rainfall. The relevance of these results to vector control in northern Venezuela is discussed.

  7. Anopheles fauna of coastal Cayenne, French Guiana: modelling and mapping of species presence using remotely sensed land cover data

    PubMed Central

    Adde, Antoine; Dusfour, Isabelle; Roux, Emmanuel; Girod, Romain; Briolant, Sébastien

    2016-01-01

    Little is known about the Anopheles species of the coastal areas of French Guiana, or their spatiotemporal distribution or environmental determinants. The present study aimed to (1) document the distribution of Anopheles fauna in the coastal area around Cayenne, and (2) investigate the use of remotely sensed land cover data as proxies of Anopheles presence. To characterise the Anopheles fauna, we combined the findings of two entomological surveys that were conducted during the period 2007-2009 and in 2014 at 37 sites. Satellite imagery data were processed to extract land cover variables potentially related to Anopheles ecology. Based on these data, a methodology was formed to estimate a statistical predictive model of the spatial-seasonal variations in the presence of Anopheles in the Cayenne region. Two Anopheles species, known as main malaria vectors in South America, were identified, including the more dominant An. aquasalis near town and rural sites, and An. darlingi only found in inland sites. Furthermore, a cross-validated model of An. aquasalis presence that integrated marsh and forest surface area was extrapolated to generate predictive maps. The present study supports the use of satellite imagery by health authorities for the surveillance of malaria vectors and planning of control strategies. PMID:27982304

  8. Population fluctuation of Anopheles (Diptera: Culicidae) in forest and forest edge habitats in Tucumán province, Argentina.

    PubMed

    Dantur Juri, M J; Almirón, W R; Claps, G L

    2010-06-01

    The aim of this work was to study the possible effects of forest and forest edge habitats on the population fluctuation of the Anopheles species in northwestern Argentina, taking into consideration the relationship between this fluctuation and climatic variables. This study is one of the first that involves the Anopheles fauna in the country and its dynamics in two different habitats. Sampling was carried out from October, 2002 to October, 2003, in the forest and on the forest edge. Both habitats were compared for species diversity and abundance, and multiple regression analyses were performed to analyze the effects of environmental variables on the population dynamics. Five hundred and sixteen adult specimens of Anopheles species were collected, the most numerous group being Arribalzaga (52.1%), followed by Anopheles (Nyssorhynchus) strodei (20.5%) and Anopheles (Nyssorhynchus) evansae (6.4%). Mosquito abundance was greatest in the forest, the most productive habitat. Samples were collected throughout the sampling period, with a smaller peak in summer. Small numbers of Anopheles (Anopheles) pseudopunctipennis were found throughout the year. Relative humidity, with a 15-day delay, was the factor that most strongly contributed to the temporal sample fluctuation. We conclude that the best season for anopheline development in the study area is from spring to fall, although the period with the greatest transmission risk is the fall, with the greatest An. pseudopunctipennis abundance.

  9. Anopheles fauna of coastal Cayenne, French Guiana: modelling and mapping of species presence using remotely sensed land cover data.

    PubMed

    Adde, Antoine; Dusfour, Isabelle; Roux, Emmanuel; Girod, Romain; Briolant, Sébastien

    2016-12-01

    Little is known about the Anopheles species of the coastal areas of French Guiana, or their spatiotemporal distribution or environmental determinants. The present study aimed to (1) document the distribution of Anopheles fauna in the coastal area around Cayenne, and (2) investigate the use of remotely sensed land cover data as proxies of Anopheles presence. To characterise the Anopheles fauna, we combined the findings of two entomological surveys that were conducted during the period 2007-2009 and in 2014 at 37 sites. Satellite imagery data were processed to extract land cover variables potentially related to Anopheles ecology. Based on these data, a methodology was formed to estimate a statistical predictive model of the spatial-seasonal variations in the presence of Anopheles in the Cayenne region. Two Anopheles species, known as main malaria vectors in South America, were identified, including the more dominant An. aquasalis near town and rural sites, and An. darlingi only found in inland sites. Furthermore, a cross-validated model of An. aquasalis presence that integrated marsh and forest surface area was extrapolated to generate predictive maps. The present study supports the use of satellite imagery by health authorities for the surveillance of malaria vectors and planning of control strategies.

  10. Filling the Gap 115 Years after Ronald Ross: The Distribution of the Anopheles coluzzii and Anopheles gambiae s.s from Freetown and Monrovia, West Africa

    PubMed Central

    de Souza, Dziedzom K.; Koudou, Benjamin G.; Bolay, Fatorma K.; Boakye, Daniel A.; Bockarie, Moses J.

    2013-01-01

    It was in Freetown, Sierra Leone, that the malaria mosquito Anopheles coastalis, now known as Anopheles gambiae, was first discovered as the vector of malaria, in 1899. That discovery led to a pioneering vector research in Sierra Leone and neighbouring Liberia, where mosquito species were extensively characterized. Unfortunately, the decade long civil conflicts of the 1990s, in both countries, resulted in a stagnation of the once vibrant research on disease vectors. This paper attempts to fill in some of the gaps on what is now known of the distribution of the sibling species of the An. gambiae complex, and especially the An. coluzzii and An. gambiae s.s, formerly known as the An. gambiae molecular M and S forms respectively, in the cities of Freetown and Monrovia. PMID:23741429

  11. A High-Affinity Adenosine Kinase from Anopheles Gambiae

    SciTech Connect

    M Cassera; M Ho; E Merino; E Burgos; A Rinaldo-Matthis; S Almo; V Schramm

    2011-12-31

    Genome analysis revealed a mosquito orthologue of adenosine kinase in Anopheles gambiae (AgAK; the most important vector for the transmission of Plasmodium falciparum in Africa). P. falciparum are purine auxotrophs and do not express an adenosine kinase but rely on their hosts for purines. AgAK was kinetically characterized and found to have the highest affinity for adenosine (K{sub m} = 8.1 nM) of any known adenosine kinase. AgAK is specific for adenosine at the nucleoside site, but several nucleotide triphosphate phosphoryl donors are tolerated. The AgAK crystal structure with a bound bisubstrate analogue Ap{sub 4}A (2.0 {angstrom} resolution) reveals interactions for adenosine and ATP and the geometry for phosphoryl transfer. The polyphosphate charge is partly neutralized by a bound Mg{sup 2+} ion and an ion pair to a catalytic site Arg. The AgAK structure consists of a large catalytic core in a three-layer {alpha}/{beta}/{alpha} sandwich, and a small cap domain in contact with adenosine. The specificity and tight binding for adenosine arise from hydrogen bond interactions of Asn14, Leu16, Leu40, Leu133, Leu168, Phe168, and Thr171 and the backbone of Ile39 and Phe168 with the adenine ring as well as through hydrogen bond interactions between Asp18, Gly64, and Asn68 and the ribosyl 2'- and 3'-hydroxyl groups. The structure is more similar to that of human adenosine kinase (48% identical) than to that of AK from Toxoplasma gondii (31% identical). With this extraordinary affinity for AgAK, adenosine is efficiently captured and converted to AMP at near the diffusion limit, suggesting an important role for this enzyme in the maintenance of the adenine nucleotide pool. mRNA analysis verifies that AgAK transcripts are produced in the adult insects.

  12. Innate host selection in Anopheles vestitipennis from southern Mexico.

    PubMed

    Ullo, Armando; Arredondo-Jiménez, Juan I; Rodríguez, Mario H; Fernández-Salas, Ildefonso; González-Cerón, Lilia

    2004-12-01

    We assessed the degree of host specificity of the purported anthropophilic and zoophilic populations of Anopheles vestitipennis. A series of experiments were conducted in an experimental hut with 3 compartments lined with nylon netting. A central release compartment and 2 side compartments were each baited with equivalent surface area of human and animal baits. Wild An. vestitipennis collected on each host, as well as corresponding F1 mosquitoes, were released in the central compartment. Overall, 22% (166/748) of all mosquitoes collected on humans were recaptured in the human compartment, whereas 23% of mosquitoes originally collected on animals were recaptured in this compartment. Experiments with F1 females resulted in 59% human selection rates, a 2.6 times increase compared with wild anthropophilic females, while a 1.2 times decrease in human selection rates (from 24% to 20%) was observed in F1 of wild zoophilic females. Host selection experiments in the Lacandón Forest revealed the same trend. These findings suggested that the complex mode of inheritance that resulted in female mosquitoes showing a stronger tendency to return to their preferred host was obscured by the nature of the method of collection, i.e., wild parental females selecting a host either innately or opportunistically, the majority of which were likely innately attracted. This was revealed by F1 females, of which, when given the choice to select a host, a higher proportion opted for the preferred one. The results presented here are in accordance with other studies that identified a subpopulation of An. vestitipennis in southern Mexico with higher anthropophily.

  13. The dance of male Anopheles gambiae in wild mating swarms.

    PubMed

    Butail, Sachit; Manoukis, Nicholas C; Diallo, Moussa; Ribeiro, José M C; Paley, Derek A

    2013-05-01

    An important element of mating in the malaria vector Anopheles gambiae Giles in nature is the crepuscular mating aggregation (swarm) composed almost entirely of males, where most coupling and insemination is generally believed to occur. In this study, we mathematically characterize the oscillatory movement of male An. gambiae in terms of an established individual-based mechanistic model that parameterizes the attraction of a mosquito toward the center of the swarm using the natural frequency of oscillation and the resistance to its motion, characterized by the damping ratio. Using three-dimensional trajectory data of ten wild mosquito swarms filmed in Mali, Africa, we show two new results for low and moderate wind conditions, and indicate how these results may vary in high wind. First, we show that in low and moderate wind the vertical component of the mosquito motion has a lower frequency of oscillation and higher damping ratio than horizontal motion. In high wind, the vertical and horizontal motions are similar to one another and the natural frequencies are higher than in low and moderate wind. Second, we show that the predicted average disagreement in the direction of motion of swarming mosquitoes moving randomly is greater than the average disagreement we observed between each mosquito and its three closest neighbors, with the smallest level of disagreement occurring for the nearest neighbor in seven out of 10 swarms. The alignment of the direction of motion between nearest neighbors is the highest in high wind. This result provides evidence for flight-path coordination between swarming male mosquitoes.

  14. Plasmodium infection alters Anopheles gambiae detoxification gene expression

    PubMed Central

    2010-01-01

    Background Anopheles gambiae has been shown to change its global gene expression patterns upon Plasmodium infection. While many alterations are directly related to the mosquito's innate immune response, parasite invasion is also expected to generate toxic by-products such as free radicals. The current study aimed at identifying which loci coding for detoxification enzymes are differentially expressed as a function of Plasmodium berghei infection in midgut and fat body tissues. Results Using a custom-made DNA microarray, transcript levels of 254 loci primarily belonging to three major detoxification enzyme families (glutathione S-transferases, cytochrome P450 monooxygenases and esterases) were compared in infected and uninfected mosquitoes both during ookinete invasion and the release of sporozoites into the hemocoel. The greatest changes in gene expression were observed in the midgut in response to ookinete invasion. Interestingly, many detoxification genes including a large number of P450s were down-regulated at this stage. In the fat body, while less dramatic, gene expression alterations were also observed and occurred during the ookinete invasion and during the release of sporozoites into the hemocoel. While most gene expression changes were tissue-related, CYP6M2, a CYP previously associated with insecticide resistance, was over-expressed both in the midgut and fat body during ookinete invasion. Conclusions Most toxicity-related reactions occur in the midgut shortly after the ingestion of an infected blood meal. Strong up-regulation of CYP6M2 in the midgut and the fat body as well as its previous association with insecticide resistance shows its broad role in metabolic detoxification. PMID:20482856

  15. Dry season reproductive depression of Anopheles gambiae in the Sahel

    PubMed Central

    Yaro, Alpha S.; Traoré, Adama; Huestis, Diana L.; Adamou, Abdoulaye; Timbiné, Seydou; Kassogué, Yaya; Diallo, Moussa; Dao, Adama; Traoré, Sékou F.; Lehmann, Tovi

    2016-01-01

    The African malaria mosquito, Anopheles gambiae, is widespread south of the Sahara including in dry savannahs and semi-arid environments where no surface water exists for several months a year. Adults of the M form of An. gambiae persist through the long dry season, when no surface waters are available, by increasing their maximal survival from 4 weeks to 7 months. Dry season diapause (aestivation) presumably underlies this extended survival. Diapause in adult insects is intrinsically linked to depressed reproduction. To determine if reproduction of the Sahelian M form is depressed during the dry season, we assessed seasonal changes in oviposition, egg batch size, and egg development, as well as insemination rate and blood feeding in wild caught mosquitoes. Results from xeric Sahelian and riparian populations were compared. Oviposition response in the Sahelian M form dropped from 70% during the wet season to 20% during the dry season while the mean egg batch size among those that laid eggs fell from 173 to 101. Correspondingly, the fraction of females that exhibited gonotrophic dissociation increased over the dry season from 5% to 45%, while a similar fraction of the population retained developed eggs despite having access to water. This depression in reproduction the Sahelian M form was not caused by a reduced insemination rate. Seasonal variation in these reproductive parameters of the riparian M form population was less extreme and the duration of reproductive depression was shorter. Blood feeding responses did not change with the season in either population. Depressed reproduction during the dry season in the Sahelian M form of An. gambiae provides additional evidence for aestivation and illuminates the physiological processes involved. The differences between the Sahelian and riparian population suggest an adaptive cline in aestivation phenotypes between populations only 130 km apart. PMID:22609421

  16. Ion and solute transport by Prestin in Drosophila and Anopheles.

    PubMed

    Hirata, Taku; Czapar, Anna; Brin, Lauren; Haritonova, Alyona; Bondeson, Daniel P; Linser, Paul; Cabrero, Pablo; Thompson, James; Dow, Julian A T; Romero, Michael F

    2012-04-01

    The gut and Malpighian tubules of insects are the primary sites of active solute and water transport for controlling hemolymph and urine composition, pH, and osmolarity. These processes depend on ATPase (pumps), channels and solute carriers (Slc proteins). Maturation of genomic databases enables us to identify the putative molecular players for these processes. Anion transporters of the Slc4 family, AE1 and NDAE1, have been reported as HCO(3)(-) transporters, but are only part of the story. Here we report Dipteran (Drosophila melanogaster (d) and Anopheles gambiae (Ag)) anion exchangers, belonging to the Slc26 family, which are multi-functional anion exchangers. One Drosophila and two Ag homologues of mammalian Slc26a5 (Prestin) and Slc26a6 (aka, PAT1, CFEX) were identified and designated dPrestin, AgPrestinA and AgPrestinB. dPrestin and AgPrestinB show electrogenic anion exchange (Cl(-)/nHCO(3)(-), Cl(-)/SO(4)(2-) and Cl(-)/oxalate(2-)) in an oocyte expression system. Since these transporters are the only Dipteran Slc26 proteins whose transport is similar to mammalian Slc26a6, we submit that Dipteran Prestin are functional and even molecular orthologues of mammalian Slc26a6. OSR1 kinase increases dPrestin ion transport, implying another set of physiological processes controlled by WNK/SPAK signaling in epithelia. All of these mRNAs are highly expressed in the gut and Malpighian tubules. Dipteran Prestin proteins appear suited for central roles in bicarbonate, sulfate and oxalate metabolism including generating the high pH conditions measured in the Dipteran midgut lumen. Finally, we present and discuss Drosophila genetic models that integrate these processes.

  17. Breakdown in the Process of Incipient Speciation in Anopheles gambiae

    PubMed Central

    Nwakanma, Davis C.; Neafsey, Daniel E.; Jawara, Musa; Adiamoh, Majidah; Lund, Emily; Rodrigues, Amabelia; Loua, Kovana M.; Konate, Lassana; Sy, Ngayo; Dia, Ibrahima; Awolola, T. Samson; Muskavitch, Marc A. T.; Conway, David J.

    2013-01-01

    Understanding genetic causes and effects of speciation in sympatric populations of sexually reproducing eukaryotes is challenging, controversial, and of practical importance for controlling rapidly evolving pests and pathogens. The major African malaria vector mosquito Anopheles gambiae sensu stricto (s.s.) is considered to contain two incipient species with strong reproductive isolation, hybrids between the M and S molecular forms being very rare. Following recent observations of higher proportions of hybrid forms at a few sites in West Africa, we conducted new surveys of 12 sites in four contiguous countries (The Gambia, Senegal, Guinea-Bissau, and Republic of Guinea). Identification and genotyping of 3499 A. gambiae s.s. revealed high frequencies of M/S hybrid forms at each site, ranging from 5 to 42%, and a large spectrum of inbreeding coefficient values from 0.11 to 0.76, spanning most of the range expected between the alternative extremes of panmixia and assortative mating. Year-round sampling over 2 years at one of the sites in The Gambia showed that M/S hybrid forms had similar relative frequencies throughout periods of marked seasonal variation in mosquito breeding and abundance. Genome-wide scans with an Affymetrix high-density single-nucleotide polymorphism (SNP) microarray enabled replicate comparisons of pools of different molecular forms, in three separate populations. These showed strong differentiation between M and S forms only in the pericentromeric region of the X chromosome that contains the molecular form-specific marker locus, with only a few other loci showing minor differences. In the X chromosome, the M/S hybrid forms were more differentiated from M than from S forms, supporting a hypothesis of asymmetric introgression and backcrossing. PMID:23335339

  18. Characterization of the multicopper oxidase gene family in Anopheles gambiae

    PubMed Central

    Gorman, Maureen J.; Dittmer, Neal T.; Marshall, Jeremy L.; Kanost, Michael R.

    2008-01-01

    The multicopper oxidase (MCO) family of enzymes includes laccases, which oxidize a broad range of substrates including diphenols, and several oxidases with specific substrates such as iron, copper or ascorbic acid. We have identified five putative MCO genes in the genome of Anopheles gambiae and have cloned cDNAs encompassing the full coding region for each gene. MCO1 mRNA was detected in all developmental stages and in all of the larval and adult tissues tested. We observed an increase in MCO1 transcript abundance in the midguts and Malphighian tubules of adult females following a blood meal and in adult abdominal carcasses in response to an immune challenge. Two alternatively spliced isoforms of MCO2 mRNA were identified. The A isoform of MCO2 was previously detected in larval and pupal cuticle where it probably catalyzes sclerotization reactions (He et al., 2007). The B isoform was transcriptionally upregulated in ovaries in response to a blood meal. MCO3 mRNA was detected in the adult midgut, Malpighian tubules, and male reproductive tissues; like MCO1, it was upregulated in response to an immune challenge or a blood meal. MCO4 and MCO5 were observed primarily in eggs and in the abdominal carcass of larvae. A phylogenetic analysis of insect MCO genes identified putative orthologs of MCO1 and MCO2 in all of the insect genomes tested, whereas MCO3, MCO4 and MCO5 were found only in the two mosquito species analyzed. MCO2 orthologs have especially high sequence similarity, suggesting that they are under strong purifying selection; the A isoforms are more conserved than the B isoforms. The mosquito specific group shares a common ancestor with MCO2. This initial study of mosquito MCOs suggests that MCO2 may be required for egg development or eggshell tanning in addition to cuticle tanning, while MCO1 and MCO3 may be involved in metal metabolism or immunity. PMID:18675911

  19. A mark release-recapture study to define the flight behaviors of Anopheles vestitipennis and Anopheles albimanus in Belize, Central America.

    PubMed

    Achee, Nicole L; Grieco, John P; Andre, Richard G; Rejmankova, Eliska; Roberts, Donald R

    2007-09-01

    The recapture rates of wild-caught, unengorged Anopheles vestitipennis and Anopheles albimanus females were determined at 0, 400, and 800 m from a fixed release point in Belize, Central America. Three sampling trials, each consisting of two 12-hour collections, were performed at each distance during September-October 2003. A total of 1,621 An. vestitipennis and 1,326 An. albimanus were marked and released during the course of the study. The recapture rate of An. vestitipennis was greatest at 0 m (7.9%; 44/ 556) and declined from 3.0% (16/531) at 400 m to 0.2% (1/534) at 800 m. Anopheles albimanus females were recaptured only at the 0-m distance and in extremely low numbers (1.1%; 5/446). Biting patterns for the unmarked natural populations were similar to those previously described for Belize, and recaptures for both species occurred during these normal biting times. The overall recapture rates for An. vestitipennis (3.76%; 61/ 1,621) and An. albimanus (0.38%; 5/1,326) indicate that An. vestitipennis has a higher probability of being attracted to a human habitation.

  20. Distribution and Larval Habitats of Anopheles Species in Northern Gyeonggi Province, Republic of Korea

    DTIC Science & Technology

    2011-06-01

    preferences for oviposition , extensive larval collections that identify breeding sites based on stages of larval development are...species composition and population densities, habitat preferences based on species composition and relative population densities, and...including habitat preferences . Anopheles sinensis, considered a secondary malaria vector by some (Lee et al. 2007, Joshi et al. 2009), is

  1. Tyrosine Hydroxylase is crucial for maintaining pupal tanning and immunity in Anopheles sinensis

    PubMed Central

    Qiao, Liang; Du, Minghui; Liang, Xin; Hao, Youjin; He, Xiu; Si, Fengling; Mei, Ting; Chen, Bin

    2016-01-01

    Tyrosine hydroxylase (TH), the initial enzyme in the melanin pathway, catalyzes tyrosine conversion into Dopa. Although expression and regulation of TH have been shown to affect cuticle pigmentation in insects, no direct functional studies to date have focused on the specific physiological processes involving the enzyme during mosquito development. In the current study, silencing of AsTH during the time period of continuous high expression in Anopheles sinensis pupae led to significant impairment of cuticle tanning and thickness, imposing a severe obstacle to eclosion in adults. Meanwhile, deficiency of melanin in interference individuals led to suppression of melanization, compared to control individuals. Consequently, the ability to defend exogenous microorganisms declined sharply. Accompanying down-regulation of the basal expression of five antimicrobial peptide genes resulted in further significant weakening of immunity. TH homologs as well as the composition of upstream transcription factor binding sites at the pupal stage are highly conserved in the Anopheles genus, implying that the TH-mediated functions are crucial in Anopheles. The collective evidence strongly suggests that TH is essential for Anopheles pupae tanning and immunity and provides a reference for further studies to validate the utility of the key genes involved in the melanization pathway in controlling mosquito development. PMID:27416870

  2. Behavioural response of the malaria vector Anopheles gambiae to host plant volatiles and synthetic blends

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugar feeding is critical for survival of malaria vectors and, although discriminative plant feeding previously has been shown to occur in Anopheles gambiae s.s., little is known about the cues mediating attraction to these plants. In this study, we investigated the role of olfaction in An. gambiae ...

  3. [Radiosensitivity curve of different stages of spermatogenesis of Anopheles atroparvus (Diptera:Nematocera)].

    PubMed

    Lecis, A R; Figus, V; Santarini, C

    1975-01-01

    In order to obtain a dose-hatchability curve for irradiated spermatogenetic stages of Anopheles atroparvus, we have irradiated with the same dose "4500 r" young fourth larval stages, old fourth larval stages, nymphae and adult males. Those different stages represent different phases of spermatogenesis. The peak of radiosensitivity for embryonic mortality, was found in spermatids, lowest appeared in spermatogonies.

  4. Pyrethroid and DDT Resistance and Organophosphate Susceptibility among Anopheles spp. Mosquitoes, Western Kenya.

    PubMed

    Wanjala, Christine L; Mbugi, Jernard P; Ototo, Edna; Gesuge, Maxwell; Afrane, Yaw A; Atieli, Harrysone E; Zhou, Guofa; Githeko, Andrew K; Yan, Guiyun

    2015-12-01

    We conducted standard insecticide susceptibility testing across western Kenya and found that the Anopheles gambiae mosquito has acquired high resistance to pyrethroids and DDT, patchy resistance to carbamates, but no resistance to organophosphates. Use of non-pyrethroid-based vector control tools may be preferable for malaria prevention in this region.

  5. Morphological, Molecular, and Chromosomal Discrimination of Cryptic Anopheles (Nyssorhynchus) (Diptera: Culicidae) from South America

    DTIC Science & Technology

    1998-09-01

    Morphological, Molecular , and Chromosomal Discrimination of Cryptic Anopheies (A?~ssorhynchus) (Diptera: Culicidae) from South America L. P...appraisal of molecular , chromosomal, and morphological characters, we conclude herein that the 2 taxa are specifically distinct and remove An. trinkae...TITLE AND SUBTITLE Morphological, Molecular , and Chromosomal Discrimination of Cryptic Anopheles( Nyssorhynchus) (Diptera: Culicidae) from South

  6. Anopheles (Nyssorhynchus) Pictipennis: A New Mosquito Record from the Atacama Region of Northern Chile

    DTIC Science & Technology

    2008-01-01

    Santiago, this species rarely feeds on humans, but it is highly attracted to domestic animals (Linthicum 1988). In this paper, we report An. (N...Mosq Control Assoc 12:619-626. Neghme AR. 1943. Contribucion a la biologia del Anopheles pictipenllis (Philippi, 1865). I. Communica- cion

  7. Pyrethroid and DDT Resistance and Organophosphate Susceptibility among Anopheles spp. Mosquitoes, Western Kenya

    PubMed Central

    Wanjala, Christine L.; Mbugi, Jernard P.; Ototo, Edna; Gesuge, Maxwell; Afrane, Yaw A.; Atieli, Harrysone E.; Zhou, Guofa; Githeko, Andrew K.

    2015-01-01

    We conducted standard insecticide susceptibility testing across western Kenya and found that the Anopheles gambiae mosquito has acquired high resistance to pyrethroids and DDT, patchy resistance to carbamates, but no resistance to organophosphates. Use of non–pyrethroid-based vector control tools may be preferable for malaria prevention in this region. PMID:26583525

  8. Molecular Comparison of Topotypic Specimens Confirms Anopheles (Nyssorhynchus) dunhami Causey (Diptera: Culicidae) in the Colombian Amazon

    DTIC Science & Technology

    2010-11-01

    of Health, Albany, NY, USA 5Facultad de Medicina , Universidad Nacional de Colombia, Bogotá, Colombia 6Programa de Estudio y Control de Enfermedades...Tropicales, Facultad de Medicina , Universidad de Antioquia, Medellín, Colombia The presence of Anopheles (Nyssorhynchus) dunhami Causey in Colombia

  9. A study of the blood-feeding patterns of Anopheles mosquitos through precipitin tests*

    PubMed Central

    1960-01-01

    The success of malaria eradication campaigns depends on the use of all methods which make for a better understanding of the biology and behaviour of mosquito vectors. One such method is precipitin testing, by which it is possible to identify the human or animal origin of blood meals of mosquitos and thereby to determine their host preferences and vectorial importance, both generally and locally. In 1955, the World Health Organization in agreement with the Lister Institute of Preventive Medicine, Elstree, England, set up a precipitin test service related to entomological surveys in malaria eradication programmes and available to national research and WHO field personnel. The purpose was to stimulate interest in the study of bionomics of Anopheles species, to facilitate the identification of blood meals of Anopheles, to eliminate experimental errors by the use of a standardized technique and highly sensitive antisera, and finally to apply the results in the strategy of malaria eradication. The results obtained over the past five years are summarized in tabular form. The study—the largest ever undertaken—included 51 species of Anopheles and 56 377 tests, of which 93.9% yielded positive results, are reviewed. The available knowledge of the vectorial importance of 39 species of Anopheles is compared with their human blood ratio, this term being used to express the percentage of human blood in relation to all precipitin tests found positive. PMID:20604062

  10. Anopheles species composition explains differences in Plasmodium transmission in La Guajira, northern Colombia.

    PubMed

    Herrera-Varela, Manuela; Orjuela, Lorena I; Peñalver, Cilia; Conn, Jan E; Quiñones, Martha L

    2014-11-01

    Malaria in La Guajira, the most northern state of Colombia, shows two different epidemiological patterns. Malaria is endemic in the municipality of Dibulla whereas in Riohacha it is characterised by sporadic outbreaks. This study aimed to establish whether differences in transmission patterns could be attributed to different vector species. The most abundant adult female species were Anopheles aquasalis, exclusive to Riohacha, and Anopheles darlingi, restricted to Dibulla. Anopheles mosquitoes were identified using morphology and the molecular markers internal transcribed spacer 2 and cytochrome c oxidase I. All specimens (n = 1,393) were tested by ELISA to determine natural infection rates with Plasmodium falciparum and Plasmodium vivax. An. darlingi was positive for P. vivax 210, with an infection rate of 0.355% and an entomological inoculation rate of 15.87 infective bites/person/year. Anopheles albimanus larvae were the most common species in Riohacha, found in temporary swamps; in contrast, in Dibulla An. darlingi were detected mainly in permanent streams. Distinctive species composition and larval habitats in each municipality may explain the differences in Plasmodium transmission and suggest different local strategies should be used for vector control.

  11. Batkoa apiculata (Thaxter) Humber affecting Anopheles (Diptera: Culicidae) in the municipality of Una, Southern Bahia, Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surveys for fungal pathogens affecting adult mosquitoes from the genus Anopheles were conducted in flooded and swamp-like natural breeding sites near residences in the center and suburbs of the city of Una as well as the nearby village of Outeiro in southern Bahia. Surveys of 54 mosquito breeding si...

  12. Anopheles species composition explains differences in Plasmodium transmission in La Guajira, northern Colombia

    PubMed Central

    Herrera-Varela, Manuela; Orjuela, Lorena I; Peñalver, Cilia; Conn, Jan E; Quiñones, Martha L

    2014-01-01

    Malaria in La Guajira, the most northern state of Colombia, shows two different epidemiological patterns. Malaria is endemic in the municipality of Dibulla whereas in Riohacha it is characterised by sporadic outbreaks. This study aimed to establish whether differences in transmission patterns could be attributed to different vector species. The most abundant adult female species were Anopheles aquasalis, exclusive to Riohacha, and Anopheles darlingi, restricted to Dibulla. Anopheles mosquitoes were identified using morphology and the molecular markers internal transcribed spacer 2 and cytochrome c oxidase I. All specimens (n = 1,393) were tested by ELISA to determine natural infection rates with Plasmodium falciparum and Plasmodium vivax. An. darlingi was positive for P. vivax 210, with an infection rate of 0.355% and an entomological inoculation rate of 15.87 infective bites/person/year. Anopheles albimanus larvae were the most common species in Riohacha, found in temporary swamps; in contrast, in Dibulla An. darlingi were detected mainly in permanent streams. Distinctive species composition and larval habitats in each municipality may explain the differences in Plasmodium transmission and suggest different local strategies should be used for vector control. PMID:25411002

  13. Genomic and evolutionary analyses of Tango transposons in Aedes aegypti, Anopheles gambiae and other mosquito species.

    PubMed

    Coy, M R; Tu, Z

    2007-08-01

    Tango is a transposon of the Tc1 family and was originally discovered in the African malaria mosquito, Anopheles gambiae. Here we report a systematic analysis of the genome sequence of the yellow fever mosquito, Aedes aegypti, which uncovered three distinct Tango transposons. We name the only An. gambiae Tango transposon AgTango1 and the three Ae. aegypti Tango elements AeTango1-3. Like AgTango1, AeTango1 and AeTango2 elements both have members that retain characteristics of autonomous elements such as intact open reading frames and terminal inverted repeats (TIRs). AeTango3 is a degenerate transposon with no full-length members. All full-length Tango transposons contain subterminal direct repeats within their TIRs. AgTango1 and AeTango1-3 form a single clade among other Tc1 transposons. Within this clade, AgTango1 and AeTango1 are closely related and share approximately 80% identity at the amino acid level, which exceeds the level of similarity of the majority of host genes in the two species. A survey of Tango in other mosquito species was carried out using degenerate PCR. Tango was isolated and sequenced in all members of the An. gambiae species complex, Aedes albopictus and Ochlerotatus atropalpus. Oc. atropalpus contains a rich diversity of Tango elements, while Tango elements in Ae. albopictus and the An. gambiae species complex all belong to Tango1. No Tango was detected in Culex pipiens quinquefasciatus, Anopheles stephensi, Anopheles dirus, Anopheles farauti or Anopheles albimanus using degenerate PCR. Bioinformatic searches of the Cx. p. quinquefasciatus (~10 x coverage) and An. stephensi (0.33 x coverage) databases also failed to uncover any Tango elements. Although other evolutionary scenarios cannot be ruled out, there are indications that Tango1 underwent horizontal transfer among divergent mosquito species.

  14. Complete mtDNA genomes of Anopheles darlingi and an approach to anopheline divergence time

    PubMed Central

    2010-01-01

    Background The complete sequences of the mitochondrial genomes (mtDNA) of members of the northern and southern genotypes of Anopheles (Nyssorhynchus) darlingi were used for comparative studies to estimate the time to the most recent common ancestor for modern anophelines, to evaluate differentiation within this taxon, and to seek evidence of incipient speciation. Methods The mtDNAs were sequenced from mosquitoes from Belize and Brazil and comparative analyses of structure and base composition, among others, were performed. A maximum likelihood approach linked with phylogenetic information was employed to detect evidence of selection and a Bayesian approach was used to date the split between the subgenus Nyssorhynchus and other Anopheles subgenera. Results The comparison of mtDNA sequences within the Anopheles darlingi taxon does not provide sufficient resolution to establish different units of speciation within the species. In addition, no evidence of positive selection in any protein-coding gene of the mtDNA was detected, and purifying selection likely is the basis for this lack of diversity. Bayesian analysis supports the conclusion that the most recent ancestor of Nyssorhynchus and Anopheles+Cellia was extant ~94 million years ago. Conclusion Analyses of mtDNA genomes of Anopheles darlingi do not provide support for speciation in the taxon. The dates estimated for divergence among the anopheline groups tested is in agreement with the geological split of western Gondwana (95 mya), and provides additional support for explaining the absence of Cellia in the New World, and Nyssorhynchus in the Afro-Eurasian continents. PMID:20470395

  15. Complete Dosage Compensation in Anopheles stephensi and the Evolution of Sex-Biased Genes in Mosquitoes

    PubMed Central

    Jiang, Xiaofang; Biedler, James K.; Qi, Yumin; Hall, Andrew Brantley; Tu, Zhijian

    2015-01-01

    Complete dosage compensation refers to hyperexpression of the entire X or Z chromosome in organisms with heterogametic sex chromosomes (XY male or ZW female) in order to compensate for having only one copy of the X or Z chromosome. Recent analyses suggest that complete dosage compensation, as in Drosophila melanogaster, may not be the norm. There has been no systematic study focusing on dosage compensation in mosquitoes. However, analysis of dosage compensation in Anopheles mosquitoes provides opportunities for evolutionary insights, as the X chromosome of Anopheles and that of its Dipteran relative, D. melanogaster formed independently from the same ancestral chromosome. Furthermore, Culicinae mosquitoes, including the Aedes genus, have homomorphic sex-determining chromosomes, negating the need for dosage compensation. Thus, Culicinae genes provide a rare phylogenetic context to investigate dosage compensation in Anopheles mosquitoes. Here, we performed RNA-seq analysis of male and female samples of the Asian malaria mosquito Anopheles stephensi and the yellow fever mosquito Aedes aegypti. Autosomal and X-linked genes in An. stephensi showed very similar levels of expression in both males and females, indicating complete dosage compensation. The uniformity of average expression levels of autosomal and X-linked genes remained when An. stephensi gene expression was normalized by that of their Ae. aegypti orthologs, strengthening the finding of complete dosage compensation in Anopheles. In addition, we comparatively analyzed the differentially expressed genes between adult males and adult females in both species, investigated sex-biased gene chromosomal distribution patterns in An. stephensi and provided three examples where gene duplications may have enabled the acquisition of sex-specific expression during mosquito evolution. PMID:26078263

  16. Habitat characterization and spatial distribution of Anopheles sp. mosquito larvae in Dar es Salaam (Tanzania) during an extended dry period

    PubMed Central

    Sattler, Michael A; Mtasiwa, Deo; Kiama, Michael; Premji, Zul; Tanner, Marcel; Killeen, Gerry F; Lengeler, Christian

    2005-01-01

    Introduction By 2030, more than 50% of the African population will live in urban areas. Controlling malaria reduces the disease burden and further improves economic development. As a complement to treated nets and prompt access to treatment, measures targeted against the larval stage of Anopheles sp. mosquitoes are a promising strategy for urban areas. However, a precise knowledge of the geographic location and potentially of ecological characteristics of breeding sites is of major importance for such interventions. Methods In total 151 km2 of central Dar es Salaam, the biggest city of Tanzania, were systematically searched for open mosquito breeding sites. Ecologic parameters, mosquito larvae density and geographic location were recorded for each site. Logistic regression analysis was used to determine the key ecological factors explaining the different densities of mosquito larvae. Results A total of 405 potential open breeding sites were examined. Large drains, swamps and puddles were associated with no or low Anopheles sp. larvae density. The probability of Anopheles sp. larvae to be present was reduced when water was identified as "turbid". Small breeding sites were more commonly colonized by Anopheles sp. larvae. Further, Anopheles gambiae s.l. larvae were found in highly organically polluted habitats. Conclusions Clear ecological characteristics of the breeding requirements of Anopheles sp. larvae could not be identified in this setting. Hence, every stagnant open water body, including very polluted ones, have to be considered as potential malaria vector breeding sites. PMID:15649333

  17. Viruses in the Anopheles A, Anopheles B, and Tete Serogroups in the Orthobunyavirus Genus (Family Bunyaviridae) Do Not Encode an NSs Protein▿

    PubMed Central

    Mohamed, Maizan; McLees, Angela; Elliott, Richard M.

    2009-01-01

    Viruses in the genus Orthobunyavirus, family Bunyaviridae, have a genome comprising three segments (called L, M, and S) of negative-sense RNA. Serological studies have classified the >170 named virus isolates into 18 serogroups, with a few additional as yet ungrouped viruses. Until now, molecular studies and full-length S-segment nucleotide sequences were available for representatives of eight serogroups; in all cases, the S segment encodes two proteins, N (nucleocapsid) and NSs (nonstructural), in overlapping open reading frames (ORFs) that are translated from the same mRNA. The NSs proteins of Bunyamwera virus (BUNV) and California serogroup viruses have been shown to play a role in inhibiting host cell mRNA and protein synthesis, thereby preventing induction of interferon (IFN). We have determined full-length sequences of the S segments of representative viruses in the Anopheles A, Anopheles B, and Tete serogroups, and we report here that these viruses do not show evidence of having an NSs ORF. In addition, these viruses have rather longer N proteins than those in the other serogroups. Most of the naturally occurring viruses that lack the NSs protein behaved like a recombinant BUNV with the NSs gene deleted in that they failed to prevent induction of IFN-β mRNA. However, Tacaiuma virus (TCMV) in the Anopheles A serogroup inhibited IFN induction in a manner similar to that of wild-type BUNV, suggesting that TCMV has evolved an alternative mechanism, not involving a typical NSs protein, to antagonize the host innate immune response. PMID:19439468

  18. Spatial abundance and human biting rate of Anopheles arabiensis and Anopheles funestus in savannah and rice agro-ecosystems of Central Tanzania.

    PubMed

    Mboera, Leonard E G; Bwana, Veneranda M; Rumisha, Susan F; Stanley, Grades; Tungu, Patrick K; Malima, Robert C

    2015-05-18

    This study was carried out to determine the spatial variations in malaria mosquito abundance and human biting rate in five villages representing rice-irrigation and savannah ecosystems in Kilosa District, central Tanzania. The study involved five villages namely Tindiga and Malui (wetland/rice irrigation), Twatwatwa and Mbwade (dry savannah) and Kimamba (wet savannah). Indoor mosquitoes were sampled using Centers for Disease Control and Prevention light traps in three houses in each village. Anopheles gambiae s.l. molecular identification was carried out using polymerase chain reaction (PCR). A total of 936 female mosquitoes were collected. About half (46.9%) were malaria mosquitoes (Anopheles gambiae s.l.=28.6%; An. funestus= 18.3%). A total of 161 (60.1%) of the morphologically identified An. gambiae s.l. (268) and subjected to PCR analysis for speciation were genotyped as An. arabiensis. The An. funestus complex mosquitoes were composed of An. funestus funestus and An. rivulorum at the 5:1 ratio. On average, 17.9 Anopheles mosquitoes were collected per village per day. Two-thirds (62.8%) of the malaria mosquitoes were collected in Malui (rice agro-ecosystem) and the lowest number (2.3%) in Twatwatwa (dry savannah ecosystem). The biting rate per person per night for An. arabiensis+An. funestus s.s. was highest in Malui (46.0) and lowest in Twatwatwa (1.67). The parity rate of the An. funestus mosquitoes was lower compared to that of An. arabiensis and none of the mosquitoes was infected with malaria sporozoites. In conclusion, An. arabiensis is the most abundant malaria vector in Kilosa district and its variation is related to the ecological system. The heterogeneity in malaria mosquito abundance and human biting rate could be used to guide selection of locally appropriated control interventions.

  19. Species and populations of the Anopheles gambiae complex in Cameroon with special emphasis on chromosomal and molecular forms of Anopheles gambiae s.s.

    PubMed

    Wondji, Charles; Frédéric, Simard; Petrarca, Vincenzo; Etang, Josiane; Santolamazza, Federica; Della Torre, Alessandra; Fontenille, Didier

    2005-11-01

    We studied the geographical distribution of species, chromosomal, and molecular forms of the Anopheles gambiae Giles (Diptera: Culicidae) complex in 23 sites in Cameroon, Central Africa. Almost all the specimens collected in the four northern-most arid sites were Anopheles arabiensis. Anopheles melas was found in a rural locality surrounded by mangrove swamps, on the Atlantic Coast. In total, 1,525 An. gambiae s.s. females were identified down to their molecular form, and inversion polymorphisms on polytene chromosomes were scored from 186 half-gravid females. The Forest chromosomal form, with standard arrangements almost fixed on both arms of chromosome-2, was the only one observed in the southern, more humid localities. Karyotypes typical of Savanna and Mopti were recorded northwards, in the humid savannas of the Adamawa Province. The molecular forms M and S were widespread throughout Cameroon, and assort independently from the chromosomal forms. S-form populations were characterized by karyotypes typical of Forest and Savanna chromosomal forms, and M-form populations were characterized by karyotypes typical of Forest, Savanna, and Mopti. No M/S hybrid patterns were detected, although M and S mosquitoes were sympatric in 15 sites, providing further evidence for positive assortative mating within molecular forms. The observed ecogeographical distribution of M and S was peculiar: the ecological parameters involved in this distribution still need to be clarified as well as the possible role of competitive exclusion between chromosomally homosequential molecular forms. No difference was observed in host preference or in Plasmodium falciparum infection rates between sympatric M and S populations.

  20. Pre-copula acoustic behaviour of males in the malarial mosquitoes Anopheles coluzzii and Anopheles gambiae s.s. does not contribute to reproductive isolation.

    PubMed

    Simões, Patrício M V; Gibson, Gabriella; Russell, Ian J

    2017-02-01

    We reveal that males of two members of the Anopheles gambiae s.l. species complex, Anopheles coluzzii and Anopheles gambiae s.s. (hereafter A. gambiae), which are both malaria vectors, perform a stereotypical acoustic behaviour in response to pure tones at frequencies that encompass the frequency range of the female's flight-tones. This behaviour resembles that described for Culex quinquefasciatus and consists of phonotactic flight initiated by a steep increase in wing-beat frequency (WBF) followed by rapid frequency modulation (RFM) of WBF when in close proximity to the sound source. RFM was elicited without acoustic feedback or the presence of a live female, but it appears to be a stereotypic behaviour in the immediate lead up to copula formation. RFM is an independent and different behavioural process from harmonic convergence interactions used by male-female pairs for mate recognition at earlier stages of mating. Acoustic threshold for RFM was used to plot behavioural audiograms from free-flying A coluzzii and A gambiae males. These audiograms were almost identical (minima ∼400 Hz) and encompassed the WBF ranges of A coluzzii (378-601 Hz) and A gambiae (373-590 Hz) females, indicating that males of the two species share similar frequency tuning and range. Furthermore, no differences were found between the two species in their WBFs, RFM behaviour or harmonic convergence ratios. These results indicate that assortative mating between A coluzzii and A gambiae is unlikely to be based on male-specific acoustic behaviours during RFM. The significance of these findings in relation to possible mechanisms for assortative mating is discussed.

  1. Resistance Status of the Malaria Vector Mosquitoes, Anopheles stephensi and Anopheles subpictus Towards Adulticides and Larvicides in Arid and Semi-Arid Areas of India

    PubMed Central

    Tikar, S. N.; Mendki, M.J.; Sharma, A. K.; Sukumaran, D.; Veer, Vijay; Prakash, Shri; Parashar, B. D.

    2011-01-01

    Susceptibility studies of malaria vectors Anopheles stephensi Liston (Diptera: Culicidae) and An. subpictus Grassi collected during 2004–2007 from various locations of Arid and Semi-Arid Zone of India were conducted by adulticide bioassay of DDT, malathion, deltamethrin and larvicide bioassay of fenthion, temephos, chlorpyriphos and malathion using diagnostic doses. Both species from all locations exhibited variable resistance to DDT and malathion from majority of location. Adults of both the species were susceptible to Deltamethrin. Larvae of both the Anopheline species showed some evidence of resistance to chlorpyriphos followed by fenthion whereas susceptible to temephos and malathion. PMID:21870971

  2. Host selection and gonotrophic cycle length of Anopheles punctimacula in southern Mexico.

    PubMed

    Ulloa, Armando; Gonzalez-Cerón, Lilia; Rodríguez, Mario H

    2006-12-01

    The host preference, survival rates, and length of the gonotrophic cycle of Anopheles punctimacula was investigated in southern México. Mosquitoes were collected in 15-day separate experiments during the rainy and dry seasons. Daily changes in the parous-nulliparous ratio were recorded and the gonotrophic cycle length was estimated by a time series analysis. Anopheles punctimacula was most abundant during the dry season and preferred animals to humans. The daily survival rate in mosquitoes collected in animal traps was 0.96 (parity rate = 0.86; gonotrophic cycle = 4 days). The length of gonotrophic cycle of 4 days was estimated on the base of a high correlation coefficient value appearing every 4 days. The minimum time estimated for developing mature eggs after blood feeding was 72 h. The proportion of mosquitoes living enough to transmit Plasmodium vivax malaria during the dry season was 0.35.

  3. Anopheles gambiae exploits the treehole ecosystem in western Kenya: a new urban malaria risk?

    PubMed

    Omlin, Francois X; Carlson, John C; Ogbunugafor, C Brandon; Hassanali, Ahmed

    2007-12-01

    At six sites in western Kenya, we explored the presence of Anopheles immature stages in treeholes. An. gambiae larvae were found in 19 species, 13 of which are exotic. The most common exotic species were Delonix regia, Jacaranda mimosipholia, and Eucalyptus citrodora. In Kisumu city, longitudinal assessments of 10 Flamboyant trees showed repeated presence of An. gambiae s.s. in treeholes with water. Production of Anopheles larvae did not correlate with habitat volume but with habitat height, showing a strong but statistically insignificant negative correlation. During a dry season, eggs recovered by rinsing dry treeholes hatched into 2.5 +/- 3.06 An. gambiae and 7.9 +/- 8.2 Aedes larvae. In cage experiments, An. gambiae s.s. laid more eggs in water originating from treeholes than in distilled or lake water, implying preference for ovipositing in this habitat. Our findings indicate that treeholes represent a hitherto unrecognized habitat for malaria vectors, which needs further studies.

  4. Scanning electron microscopy of egg hatching of Anopheles albimanus (Diptera: Culicidae).

    PubMed

    Rodriguez, M H; Orozco, A; Chavez, B; Martinez-Palomo, A

    1992-09-01

    Scanning electron and light microscopic observations showed that egg hatching in Anopheles albimanus Wiedemann is aided by a chisel-shaped spine. This hatching tooth is surrounded by a thin flexible membrane fixed to a groove in the head of the larvae. Increased intracranial pressure may force the spine against the egg shell until a fissure is produced. Further opening of the egg is achieved by movements of the head and the entire body of the larva.

  5. Bionomics of the Primary Malaria Vector, Anopheles pseudopunctipennis, in the Tapachula Foothill Area of Southern Mexico

    DTIC Science & Technology

    1992-02-04

    of Preventive Medicine and Biometrics. and Mario Henry Rodriguez, Adjunct Associate Professor Malaria, the more important vector-borne disease in...and guidance provided by Dr. Mario Henry Rodriguez. I am very grateful for the opportunity to have worked with him in TapachuIa, Mexico. The...Mexico ( Vargas and Martinez-Palacios, 1955). Included in the list of actual and potential malaria vectors is Anopheles albimanus Wiedemann, An

  6. Preliminary observations on cross-mating of the malaria vector, Anopheles sergentii from two Egyptian oases.

    PubMed

    Kenawy, M A; Sowilem, M M; Abdel-Hamid, Y M; Wahba, M M

    2000-12-01

    Intra- and inter-strain crosses were made between randomly collected adults Anopheles sergentii originated from Tersa village (El-Faiyum Governorate) and Siwa oasis (Matruh Governorate). The success of such crosses and their effects on fecundity and fertility of the parental females and on survival and development velocities of the F1 immatures were examined. No overall heterosis effects on such attributes were detected suggesting absence of genetic differences between the vector populations in these two malarious areas.

  7. The Distribution of Circumsporozoite Protein (CS) in Anopheles Stephensi Mosquitoes Infected with Plasmodium Falciparum Malaria

    DTIC Science & Technology

    1990-01-01

    389 in differentiating oocysts, on remnant membranes left on the midgut Roitt IM, BrostoffJ, Male DK (1985): Immunology. St Louis, CV Mosby wall after...Plasmodium falciparum; Anopheles stephensi; Cir- on the mosquito midgut. As oocysts differentiated to ma- cumsporozoite protein; Fuchsin/naphthol AS-BI...and sporogony in the mosquito. During a blood meal, microscopy and an indirect fluorescent antibody test (IFAT). These the mosquito ingests the male

  8. Localized breeding of the Anopheles gambiae complex (Diptera: Culicidae) along the River Gambia, West Africa.

    PubMed

    Bøgh, C; Bøgh, C; Clarke, S E; Jawara, M; Thomas, C J; Lindsay, S W

    2003-08-01

    A study was undertaken to identify the major larval habitats of the Anopheles gambiae (Giles) complex in rural Gambia. Mosquito larvae and pupae were sampled along transects and in specific habitats in the central region of the country during the rainy seasons of 1996 and 1997. The sampling showed that the major breeding sites were located on the flooded alluvial soils bordering the river. The largest numbers of larvae were found during September, one month after the peak rains. Polymerase chain reaction analysis of specimens showed that Anopheles melas (Theobald) was the dominant species in the flooded areas (81.5%), followed by A. gambiae sensu stricto (Giles) (18.0%) and A. arabiensis (Patton) (0.5%). By sampling in specific habitats it was evident that A. arabiensis was mainly breeding in rain-fed rice fields along the edge of the alluvial soils. Anopheles melas and A. gambiae s.s. often coexisted but whereas A. melas were found in water with a salinity of up to 72% sea water (25.2 g NaCl l(-1)), A. gambiae s.s. only occurred in water with up to 30% sea water (10.5 g NaCl l(-1)). Anopheles melas larvae were found in association with plant communities dominated by sedges and grasses (Eleocharis sp., Paspalum sp., Sporobolus sp.) and sea-purslane Sesuvium portulacastrum (L.) and the presence of cattle hoof prints, whereas A. gambiae s.s. larvae mainly occurred in association with Paspalum sp. and Eleocharis sp. The study showed that even during the peak rainy season, breeding of the A. gambiae complex is almost entirely restricted to the extensive alluvial areas along the river.

  9. Morphological Analysis of Three Populations of Anopheles (Nyssorhynchus) Nuneztovari Gabaldon (Diptera: Culicidae) from Colombia

    DTIC Science & Technology

    2008-02-01

    populations of Anopheles (Nyssorhynchus) nuneztovari Gabaldón (Diptera: Culicidae) from Colombia Mayury Fajardo Ramos, Ranulfo González Obando/+, Marco...Fidel Suárez, David López, Richard Wilkerson1, Maria Anice Mureb Sallum2 Facultad de Ciencias Naturales y Exactas y Facultad de Salud , AA 25623...Universidad del Valle, Cali, Colombia 1Division of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD, US 2Departamento de

  10. Inference of the Oxidative Stress Network in Anopheles stephensi upon Plasmodium Infection

    PubMed Central

    Shrinet, Jatin; Nandal, Umesh Kumar; Adak, Tridibes; Bhatnagar, Raj K.; Sunil, Sujatha

    2014-01-01

    Ookinete invasion of Anopheles midgut is a critical step for malaria transmission; the parasite numbers drop drastically and practically reach a minimum during the parasite's whole life cycle. At this stage, the parasite as well as the vector undergoes immense oxidative stress. Thereafter, the vector undergoes oxidative stress at different time points as the parasite invades its tissues during the parasite development. The present study was undertaken to reconstruct the network of differentially expressed genes involved in oxidative stress in Anopheles stephensi during Plasmodium development and maturation in the midgut. Using high throughput next generation sequencing methods, we generated the transcriptome of the An. stephensi midgut during Plasmodium vinckei petteri oocyst invasion of the midgut epithelium. Further, we utilized large datasets available on public domain on Anopheles during Plasmodium ookinete invasion and Drosophila datasets and arrived upon clusters of genes that may play a role in oxidative stress. Finally, we used support vector machines for the functional prediction of the un-annotated genes of An. stephensi. Integrating the results from all the different data analyses, we identified a total of 516 genes that were involved in oxidative stress in An. stephensi during Plasmodium development. The significantly regulated genes were further extracted from this gene cluster and used to infer an oxidative stress network of An. stephensi. Using system biology approaches, we have been able to ascertain the role of several putative genes in An. stephensi with respect to oxidative stress. Further experimental validations of these genes are underway. PMID:25474020

  11. Thermal behaviour of Anopheles stephensi in response to infection with malaria and fungal entomopathogens

    PubMed Central

    Blanford, Simon; Read, Andrew F; Thomas, Matthew B

    2009-01-01

    Background Temperature is a critical determinant of the development of malaria parasites in mosquitoes, and hence the geographic distribution of malaria risk, but little is known about the thermal preferences of Anopheles. A number of other insects modify their thermal behaviour in response to infection. These alterations can be beneficial for the insect or for the infectious agent. Given current interest in developing fungal biopesticides for control of mosquitoes, Anopheles stephensi were examined to test whether mosquitoes showed thermally-mediated behaviour in response to infection with fungal entomopathogens and the rodent malaria, Plasmodium yoelii. Methods Over two experiments, groups of An. stephensi were infected with one of three entomopathogenic fungi, and/or P. yoelii. Infected and uninfected mosquitoes were released on to a thermal gradient (14 – 38°C) for "snapshot" assessments of thermal preference during the first five days post-infection. Mosquito survival was monitored for eight days and, where appropriate, oocyst prevalence and intensity was assessed. Results and conclusion Both infected and uninfected An. stephensi showed a non-random distribution on the gradient, indicating some capacity to behaviourally thermoregulate. However, chosen resting temperatures were not altered by any of the infections. There is thus no evidence that thermally-mediated behaviours play a role in determining malaria prevalence or that they will influence the performance of fungal biopesticides against adult Anopheles. PMID:19379519

  12. Ability of TEP1 in intestinal flora to modulate natural resistance of Anopheles dirus.

    PubMed

    Wang, Yanyan; Wang, Ying; Zhang, Jingru; Xu, Wenyue; Zhang, Jian; Huang, Fu Sheng

    2013-08-01

    Blocking transmission of malaria is a reliable way to control and eliminate infection. However, in-depth knowledge of the interaction between Plasmodium and mosquito is needed. Studies suggest that innate immunity is the main mechanism inhibiting development of malaria parasites in the mosquito. Recent studies have found that use of antibiotics that inhibit the mosquito gut flora can reduce the immune response of Anopheles gambiae, thereby contributing to the development of malaria parasites. In our study, we used the non susceptible model of Anopheles dirus-Plasmodium yoelii to explore the effect of Anopheles intestinal flora on the natural resistance of A. dirus to P. yoelii. We found that in mosquitoes infected with Plasmodium, the intestinal flora can regulate expression of thioester-containing protein (TEP1) via an RNAi gene-silencing approach. Our results suggest that in the absence of TEP1, the natural microbiota cannot suppress the development of P. yoelii in A. dirus. This suggests that AdTEP1 plays an important role in the resistance of A. dirus to P. yoelii. The intestinal flora may modulate the development of P. yoelii in A. dirus by regulating TEP1 expression.

  13. Reticulate Speciation and Barriers to Introgression in the Anopheles gambiae Species Complex.

    PubMed

    Crawford, Jacob E; Riehle, Michelle M; Guelbeogo, Wamdaogo M; Gneme, Awa; Sagnon, N'Fale; Vernick, Kenneth D; Nielsen, Rasmus; Lazzaro, Brian P

    2015-11-28

    Speciation as a process remains a central focus of evolutionary biology, but our understanding of the genomic architecture and prevalence of speciation in the face of gene flow remains incomplete. The Anopheles gambiae species complex of malaria mosquitoes is a radiation of ecologically diverse taxa. This complex is well-suited for testing for evidence of a speciation continuum and genomic barriers to introgression because its members exhibit partially overlapping geographic distributions as well as varying levels of divergence and reproductive isolation. We sequenced 20 genomes from wild A. gambiae s.s., Anopheles coluzzii, Anopheles arabiensis, and compared these with 12 genomes from the "GOUNDRY" subgroup of A. gambiae s.l. Amidst a backdrop of strong reproductive isolation, we find strong evidence for a speciation continuum with introgression of autosomal chromosomal regions among species and subgroups. The X chromosome, however, is strongly differentiated among all taxa, pointing to a disproportionately large effect of X chromosome genes in driving speciation among anophelines. Strikingly, we find that autosomal introgression has occurred from contemporary hybridization between A. gambiae and A. arabiensis despite strong divergence (∼5× higher than autosomal divergence) and isolation on the X chromosome. In addition to the X, we find strong evidence that lowly recombining autosomal regions, especially pericentromeric regions, serve as barriers to introgression secondarily to the X. We show that speciation with gene flow results in genomic mosaicism of divergence and introgression. Such a reticulate gene pool connecting vector taxa across the speciation continuum has important implications for malaria control efforts.

  14. Rubidium marking of Anopheles mosquitoes detectable by field-capable X-ray spectrometry.

    PubMed

    Wilkins, E E; Smith, S C; Roberts, J M; Benedict, M

    2007-06-01

    We present a mosquito marking technique suitable for mark-release-recapture that can be used with a hand-held, portable X-ray fluorescence (XRF) spectrometer, which is practical for field measurements. Third instar Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) and Anopheles stephensi Liston larvae were cultured to pupation in water containing rubidium (Rb) Cl at concentrations up to 1000 p.p.m. Rb. Anopheles gambiae larvae survived to adulthood at concentrations as high as 1000 p.p.m. Rb but suffered pupal mortality and reduced adult longevity at high concentrations. We were able to culture An. stephensi at Rb concentrations as high as 300 p.p.m. The presence of Rb in adults was evaluated using a portable XRF analyser, and we were able to reliably detect Rb above background levels in 10-day-old females and 4-day-old males at concentrations causing minimal pupal or adult mortality. We observed that Rb marking was not permanent, and the concentration declined significantly as adults aged. The low cost of labelling with RbCl and the field portability of the spectrometer provide a useful means for labelling mosquitoes via breeding sites or in the laboratory for mark-release-recapture experiments.

  15. Rhodopsin management during the light-dark cycle of Anopheles gambiae mosquitoes

    PubMed Central

    Moon, Young Min; Metoxen, Alexander J.; Leming, Matthew T.; Whaley, Michelle A.; O’Tousa, Joseph E.

    2014-01-01

    The tropical disease vector mosquito Anopheles gambiae possesses 11 rhodopsin genes. Three of these, GPROP1, GPROP3, and GPROP4, encode rhodopsins with >99% sequence identity. We created antisera against these rhodopsins and used immunohistology to show that one or more of these rhodopsins are expressed in the major R1-6 photoreceptor class of the adult Anopheles gambiae eye. Under dark conditions, rhodopsin accumulates within the light-sensitive rhabdomere of the photoreceptor. Light treatment, however, causes extensive movement of rhodopsin to the cytoplasmic compartment. Protein electrophoresis showed that the rhodopsin is present in two different forms. The larger form is an immature species that is deglycosylated during the posttranslational maturation process to generate the smaller, mature form. The immature form is maintained at a constant level regardless of lighting conditions. These results indicate that rhodopsin biosynthesis and movement into the rhabdomere occurs at a constant rate. In contrast, the mature form increases in abundance when animals are placed in dark conditions. Light-triggered internalization and protein degradation counteracts this rhodopsin increase and keeps rhabdomeric rhodopsin levels low in light conditions. The interplay of the constant maturation rate with light-triggered degradation causes rhodopsin to accumulate within the rhabdomere only in dark conditions. Thus, Anopheles photoreceptors possess a mechanism for adjusting light sensitivity through light-dependent control of rhodopsin levels and cellular location. PMID:25260623

  16. Anopheles stephensi Heme Peroxidase HPX15 Suppresses Midgut Immunity to Support Plasmodium Development

    PubMed Central

    Kajla, Mithilesh; Kakani, Parik; Choudhury, Tania Pal; Kumar, Vikas; Gupta, Kuldeep; Dhawan, Rini; Gupta, Lalita; Kumar, Sanjeev

    2017-01-01

    The heme peroxidase HPX15 is an evolutionary conserved anopheline lineage-specific gene. Previously, we found that this gene is present in the genome of 19 worldwide distributed different species of Anopheles mosquito and its orthologs are absent in other mosquitoes, insects, or human. In addition, 65–99% amino acid identity among these 19 orthologs permitted us to hypothesize that the functional aspects of this gene might be also conserved in different anophelines. In this study, we found that Anopheles stephensi AsHPX15 gene is mainly expressed in the midgut and highly induced after uninfected or Plasmodium berghei-infected blood feeding. RNA interference-mediated silencing of midgut AsHPX15 gene drastically reduced the number of developing P. berghei oocysts. An antiplasmodial gene nitric oxide synthase was induced 13-fold in silenced midguts when compared to the unsilenced controls. Interestingly, the induction of antiplasmodial immunity in AsHPX15-silenced midguts is in absolute agreement with Anopheles gambiae. In A. gambiae, AgHPX15 catalyzes the formation of a dityrosine network at luminal side of the midgut that suppresses the activation of mosquito immunity against the bolus bacteria. Thus, a low-immunity zone created by this mechanism indirectly supports Plasmodium development inside the midgut lumen. These indistinguishable functional behaviors and conserved homology indicates that HPX15 might be a potent target to manipulate the antiplasmodial immunity of the anopheline midgut, and it will open new frontiers in the field of malaria control. PMID:28352267

  17. Chemical Composition and Repellent Activity of Achillea vermiculata and Satureja hortensis against Anopheles stephensi

    PubMed Central

    Pirmohammadi, Masoumeh; Shayeghi, Mansoureh; Vatandoost, Hassan; Abaei, Mohammad Reza; Mohammadi, Ali; Bagheri, Akbar; Khoobdel, Mehdi; Bakhshi, Hasan; Pirmohammadi, Maryam; Tavassoli, Maryam

    2016-01-01

    Background: One of the best ways to control the malaria disease and to be protected human against Anopheles mosquito biting is the use of repellents. Throughout repellents, herbal ones may be an appropriate and safe source for protection. Methods: Chemical constituents of Achillea vermiculata and Satoreja hortensis were determined by using gas chromatography-mass spectrometry. Efficacy and the protection time of these plants were assessed on Anopheles stephensi under the laboratory condition. Results: The mean assessed protection time and efficacy for A. vermiculata was 2.16 and 3.16 hours respectively and the obtained ED50 and ED90 for this plant was 5.67 and 63 μl/cm2 respectively. The figured for S. hortensis was 4.16 and 5 hours respectively. ED50 and ED90 for this plant were 5.63 and 45.75μl/cm2 respectively. Conclusion: Results of investigation showed that S. hortensis plant has an acceptable protection time, therefore, this plant could be considered as a good herbal repellent against anopheles mosquitoes. PMID:27308278

  18. A viral over-expression system for the major malaria mosquito Anopheles gambiae

    PubMed Central

    Suzuki, Yasutsugu; Niu, Guodong; Hughes, Grant L.; Rasgon, Jason L.

    2014-01-01

    Understanding pathogen/mosquito interactions is essential for developing novel strategies to control mosquito-borne diseases. Technical advances in reverse-genetics, such as RNA interference (RNAi), have facilitated elucidation of components of the mosquito immune system that are antagonistic to pathogen development, and host proteins essential for parasite development. Forward genetic approaches, however, are limited to generation of transgenic insects, and while powerful, mosquito transgenesis is a resource- and time-intensive technique that is not broadly available to most laboratories. The ability to easily “over-express” genes would enhance molecular studies in vector biology and expedite elucidation of pathogen-refractory genes without the need to make transgenic insects. We developed and characterized an efficient Anopheles gambiae densovirus (AgDNV) over-expression system for the major malaria vector Anopheles gambiae. High-levels of gene expression were detected at 3 days post-infection and increased over time, suggesting this is an effective system for gene induction. Strong expression was observed in the fat body and ovaries. We validated multiple short promoters for gene induction studies. Finally, we developed a polycistronic system to simultaneously express multiple genes of interest. This AgDNV-based toolset allows for consistent transduction of genes of interest and will be a powerful molecular tool for research in Anopheles gambiae mosquitoes. PMID:24875042

  19. Phylogeography of the neotropical Anopheles triannulatus complex (Diptera: Culicidae) supports deep structure and complex patterns

    PubMed Central

    2013-01-01

    Background The molecular phylogenetic relationships and population structure of the species of the Anopheles triannulatus complex: Anopheles triannulatus s.s., Anopheles halophylus and the putative species Anopheles triannulatus C were investigated. Methods The mitochondrial COI gene, the nuclear white gene and rDNA ITS2 of samples that include the known geographic distribution of these taxa were analyzed. Phylogenetic analyses were performed using Bayesian inference, Maximum parsimony and Maximum likelihood approaches. Results Each data set analyzed septely yielded a different topology but none provided evidence for the seption of An. halophylus and An. triannulatus C, consistent with the hypothesis that the two are undergoing incipient speciation. The phylogenetic analyses of the white gene found three main clades, whereas the statistical parsimony network detected only a single metapopulation of Anopheles triannulatus s.l. Seven COI lineages were detected by phylogenetic and network analysis. In contrast, the network, but not the phylogenetic analyses, strongly supported three ITS2 groups. Combined data analyses provided the best resolution of the trees, with two major clades, Amazonian (clade I) and trans-Andean + Amazon Delta (clade II). Clade I consists of multiple subclades: An. halophylus + An. triannulatus C; trans-Andean Venezuela; central Amazonia + central Bolivia; Atlantic coastal lowland; and Amazon delta. Clade II includes three subclades: Panama; cis-Andean Colombia; and cis-Venezuela. The Amazon delta specimens are in both clades, likely indicating local sympatry. Spatial and molecular variance analyses detected nine groups, corroborating some of subclades obtained in the combined data analysis. Conclusion Combination of the three molecular markers provided the best resolution for differentiation within An. triannulatus s.s. and An. halophylus and C. The latest two species seem to be very closely related and the analyses performed were

  20. Comparative susceptibility of three species of Anopheles from Belize, Central America, to Plasmodium falciparum (NF-54).

    PubMed

    Grieco, John P; Achee, Nicole L; Roberts, Donald R; Andre, Richard G

    2005-09-01

    In August of 2000, a comparative susceptibility study was conducted using 3 species of Anopheles mosquitoes from Belize, Central America, and a standard species used in laboratory infection studies, Anopheles stephensi. Test populations were fed human blood infected with cultured Plasmodium falciparum (NF-54 strain) parasites via a membrane feeder. The control species, An. stephensi, exhibited the highest infections, with 73.8% of dissected specimens positive for sporozoites in the salivary glands. The control species also showed heavier sporozoite loads; 74.0% of positive glands having greater than 200 sporozoites. Of species from Belize, Anopheles darlingi was the most susceptibile, e.g., 41.0% of salivary glands were positive, with more than 200 sporozoites per gland. Anopheles vestitipennis had a low salivary gland infection rate (9.3%) and a moderate number of sporozoites in glands (i.e., 85.7% containing 50-250 sporozoites). Anopheles albimanus was the least susceptible species to infection. No specimens of An. albimanus from the Golden Stream population developed sporozoites in the salivary glands, yet 20.7% of dissected specimens had positive midgut infections. The An. albimanus Buena Vista population showed similar results with only a 2.2% salivary gland infection rate and a 21.5% midgut infection rate. Oocysts in An. stephensi increased in size by 20% after day 10. Development peaked at day 12, with a mean oocyst diameter of 58 microm at onset of oocyst differentiation. Oocysts developed more slowly in An. vestitipennis until day 10. After day 10, there was a 53% increase in oocyst development over the previous 10 days. Oocyst differentiation was not observed until day 13 postfeed. As with An. vestitipennis, both populations of An. albimanus showed similar slow rates of oocyst development; however, no dramatic growth increase occurred after day 10. The oocysts in the Golden Stream population exhibited a cessation of growth after day 10, peaking at a mean

  1. Linking Deforestation to Malaria in the Amazon: Characterization of the Breeding Habitat of the Principal Malaria Vector, Anopheles darlingi

    PubMed Central

    Vittor, Amy Y.; Pan, William; Gilman, Robert H.; Tielsch, James; Glass, Gregory; Shields, Tim; Sánchez-Lozano, Wagner; Pinedo, Viviana V.; Salas-Cobos, Erit; Flores, Silvia; Patz, Jonathan A.

    2009-01-01

    This study examined the larval breeding habitat of a major South American malaria vector, Anopheles darlingi, in areas with varying degrees of ecologic alteration in the Peruvian Amazon. Water bodies were repeatedly sampled across 112 km of transects along the Iquitos-Nauta road in ecologically varied areas. Field data and satellite imagery were used to determine the landscape composition surrounding each site. Seventeen species of Anopheles larvae were collected. Anopheles darlingi larvae were present in 87 of 844 sites (10.3%). Sites with A. darlingi larvae had an average of 24.1% forest cover, compared with 41.0% for sites without A. darlingi (P < 0.0001). Multivariate analysis identified seasonality, algae, water body size, presence of human populations, and the amount of forest and secondary growth as significant determinants of A. darlingi presence. We conclude that deforestation and associated ecologic alterations are conducive to A. darlingi larval presence, and thereby increase malaria risk. PMID:19556558

  2. Identification of a Bacillus thuringiensis Cry11Ba toxin-binding aminopeptidase from the mosquito, Anopheles quadrimaculatus

    PubMed Central

    Abdullah, Mohd Amir F; Valaitis, Algimantas P; Dean, Donald H

    2006-01-01

    Background Aminopeptidase N (APN) type proteins isolated from several species of lepidopteran insects have been implicated as Bacillus thuringiensis (Bt) toxin-binding proteins (receptors) for Cry toxins. We examined brush border membrane vesicle (BBMV) proteins from the mosquito Anopheles quadrimaculatus to determine if APNs from this organism would bind mosquitocidal Cry toxins that are active to it. Results A 100-kDa protein with APN activity (APNAnq 100) was isolated from the brush border membrane of Anopheles quadrimaculatus. Native state binding analysis by surface plasmon resonance shows that APNAnq 100 forms tight binding to a mosquitocidal Bt toxin, Cry11Ba, but not to Cry2Aa, Cry4Ba or Cry11Aa. Conclusion An aminopeptidase from Anopheles quadrimaculatus mosquitoes is a specific binding protein for Bacillus thuringiensis Cry11Ba. PMID:16716213

  3. Behavioral responses of catnip (Nepeta cataria) by two species of mosquitoes, Aedes aegypti and Anopheles harrisoni, in Thailand.

    PubMed

    Polsomboon, Suppaluck; Grieco, John P; Achee, Nicole L; Chauhan, Kamlesh R; Tanasinchayakul, Somchai; Pothikasikorn, Jinrapa; Chareonviriyaphap, Theeraphap

    2008-12-01

    An investigation of the biological effect of catnip oil (Nepeta cataria L.) on the behavioral response of field collected Aedes aegypti and Anopheles harrisoni was conducted using an automated excitorepellency test system. Aedes aegypti showed significantly higher escape rates from the contact chamber at 5% catnip oil compared to other concentrations (P < 0.05). With Anopheles harrisoni, a high escape response was seen at 2.5% catnip oil from the contact chamber, while in the noncontact chamber a higher escape response was observed at a concentration of 5%. Results showed that this compound exhibits both irritant and repellent actions.

  4. Characterization and detection of Anopheles vestitipennis and Anopheles punctimacula (Diptera: Culicidae) larval habitats in Belize with field survey and SPOT satellite imagery.

    PubMed

    Rejmankova, E; Pope, K O; Roberts, D R; Lege, M G; Andre, R; Greico, J; Alonzo, Y

    1998-06-01

    Surveys of larval habitats of Anopheles vestitipennis and Anopheles punctimacula were conducted in Belize, Central America. Habitat analysis and classification resulted in delineation of eight habitat types defined by dominant life forms and hydrology. Percent cover of tall dense macrophytes, shrubs, open water, and pH were significantly different between sites with and without An. vestitipennis. For An. punctimacula, percent cover of tall dense macrophytes, trees, detritus, open water, and water depth were significantly different between larvae positive and negative sites. The discriminant function for An. vestitipennis correctly predicted the presence of larvae in 65% of sites and correctly predicted the absence of larvae in 88% of sites. The discriminant function for An. punctimacula correctly predicted 81% of sites for the presence of larvae and 45% for the absence of larvae. Canonical discriminant analysis of the three groups of habitats (An. vestitipennis positive; An. punctimacula positive; all negative) confirmed that while larval habitats of An. punctimacula are clustered in the tree dominated area, larval habitats of An. vestitipennis were found in both tree dominated and tall dense macrophyte dominated environments. The forest larval habitats of An. vestitipennis and An. punctimacula seem to be randomly distributed among different forest types. Both species tend to occur in denser forests with more detritus, shallower water, and slightly higher pH. Classification of dry season (February) SPOT multispectral satellite imagery produced 10 land cover types with the swamp forest and tall dense marsh classes being of particular interest. The accuracy assessment showed that commission errors for the tall, dense marsh and swamp forest appeared to be minor; but omission errors were significant, especially for the swamp forest (perhaps because no swamp forests are flooded in February). This means that where the classification indicates there are An. vestitipennis

  5. Characterization and detection of Anopheles vestitipennis and Anopheles punctimacula (Diptera: Culicidae) larval habitats in Belize with field survey and SPOT satellite imagery

    NASA Technical Reports Server (NTRS)

    Rejmankova, E.; Pope, K. O.; Roberts, D. R.; Lege, M. G.; Andre, R.; Greico, J.; Alonzo, Y.

    1998-01-01

    Surveys of larval habitats of Anopheles vestitipennis and Anopheles punctimacula were conducted in Belize, Central America. Habitat analysis and classification resulted in delineation of eight habitat types defined by dominant life forms and hydrology. Percent cover of tall dense macrophytes, shrubs, open water, and pH were significantly different between sites with and without An. vestitipennis. For An. punctimacula, percent cover of tall dense macrophytes, trees, detritus, open water, and water depth were significantly different between larvae positive and negative sites. The discriminant function for An. vestitipennis correctly predicted the presence of larvae in 65% of sites and correctly predicted the absence of larvae in 88% of sites. The discriminant function for An. punctimacula correctly predicted 81% of sites for the presence of larvae and 45% for the absence of larvae. Canonical discriminant analysis of the three groups of habitats (An. vestitipennis positive; An. punctimacula positive; all negative) confirmed that while larval habitats of An. punctimacula are clustered in the tree dominated area, larval habitats of An. vestitipennis were found in both tree dominated and tall dense macrophyte dominated environments. The forest larval habitats of An. vestitipennis and An. punctimacula seem to be randomly distributed among different forest types. Both species tend to occur in denser forests with more detritus, shallower water, and slightly higher pH. Classification of dry season (February) SPOT multispectral satellite imagery produced 10 land cover types with the swamp forest and tall dense marsh classes being of particular interest. The accuracy assessment showed that commission errors for the tall, dense marsh and swamp forest appeared to be minor; but omission errors were significant, especially for the swamp forest (perhaps because no swamp forests are flooded in February). This means that where the classification indicates there are An. vestitipennis

  6. Identification of bloodmeals in Anopheles quadrimaculatus and Anopheles punctipennis from eastern equine encephalitis virus foci in northeastern U.S.A.

    PubMed

    Molaei, G; Farajollahi, A; Armstrong, P M; Oliver, J; Howard, J J; Andreadis, T G

    2009-12-01

    The host-feeding patterns of Anopheles quadrimaculatus Say and Anopheles punctipennis (Say) were examined in order to evaluate their potential contributions to the transmission of eastern equine encephalitis virus (EEEv) and other arboviruses in the northeastern U.S.A. Engorged mosquitoes of the two species were collected from EEEv foci in central New York (NY) and throughout New Jersey (NJ), and their bloodmeals were identified using a polymerase chain reaction (PCR)-based assay and sequencing portions of the mitochondrial cytochrome b gene. Analysis of 131 An. quadrimaculatus and 107 An. punctipennis from NY revealed that 97.7% and 97.2%, respectively, had acquired blood solely from mammalian hosts. Similarly, examination of 288 An. quadrimaculatus and 127 An. punctipennis from NJ showed 100% and 96.0%, respectively, contained mammalian-derived bloodmeals. Mosquitoes containing mixed bloodmeals from both avian and mammalian hosts were detected in 1.6% of An. quadrimaculatus from NY, and 2.8% and 4.0% of An. punctipennis from NY and NJ, respectively. White-tailed deer (Odocoileus virginianus) constituted the most common vertebrate host for these anopheline mosquitoes, accounting for 85.8-97.7% of all bloodmeals identified. The predominance of white-tailed deer as a source of bloodmeals supports enzootic amplification of deer-associated arboviruses in this region, including Jamestown Canyon, Cache Valley and Potosi viruses. One horse- and two human-derived bloodmeals were also detected in An. quadrimaculatus collected in NJ. Limited avian-derived bloodmeals were detected from mourning dove (Zenaida macroura), sharp-shinned hawk (Accipiter striatus) and house finch (Carpodacus mexicanus), mostly in mixed bloodmeals. Occasional feeding on avian hosts suggests that these mosquitoes may participate as epizootic-epidemic bridge vectors of EEEv from viraemic birds to mammalian hosts of concern, including horses and humans. An isolate of EEEv was recovered from the head

  7. Ecology and behavior of Anopheles arabiensis in relation to agricultural practices in central Kenya.

    PubMed

    Muturi, Ephantus J; Mwangangi, Joseph M; Beier, John C; Blackshear, Millon; Wauna, James; Sang, Rosemary; Mukabana, Wolfgang R

    2013-09-01

    Ecological changes associated with anthropogenic ecosystem disturbances can influence human risk of exposure to malaria and other vector-borne infectious diseases. This study in Mwea, Kenya, investigated the pattern of insecticide use in irrigated and nonirrigated agroecosystems and association with the density, survival, and blood-feeding behavior of the malaria vector Anopheles arabiensis. The parity rates of adult An. arabiensis from randomly selected houses were determined by examining their ovaries for tracheal distension, and polymerase chain reaction was used to identify the host blood meals. In addition, structured questionnaires were used to generate data on insecticide use. Anopheles arabiensis densities were highest in irrigated rice agroecosystems, intermediate in irrigated French beans agroecosystems, and lowest in the nonirrigated agroecosystem. Anopheles arabiensis adult survivorship was significantly lower in irrigated rice agroecosystems than in irrigated French beans agroecosystems. The human blood index (HBI) was significantly higher in the nonirrigated agroecosystem compared to irrigated agroecosystems. Moreover, there was marked variation in HBI among villages in irrigated agroecosystems with significantly lower HBI in Kangichiri and Mathangauta compared to Kiuria, Karima, and Kangai. The proportion of mosquitoes with mixed blood meals varied among villages ranging from 0.25 in Kangichiri to 0.83 in Kiuria. Sumithion, dimethoate, and alpha cypermethrin were the most commonly used insecticides. The 1st was used mostly in irrigated rice agroecosystems, and the last 2 were used mostly in irrigated French beans agroecosystems. These findings indicate that agricultural practices may influence the ecology and behavior of malaria vectors and ultimately the risk of malaria transmission.

  8. Biological cost of tolerance to heavy metals in the mosquito Anopheles gambiae.

    PubMed

    Mireji, P O; Keating, J; Hassanali, A; Mbogo, C M; Muturi, M N; Githure, J I; Beier, J C

    2010-06-01

    The global rate of heavy metal pollution is rapidly increasing in various habitats. Anopheles malaria vector species (Diptera: Culicidae) appear to tolerate many aquatic habitats with metal pollutants, despite their normal proclivity for 'clean' water (i.e. low levels of organic matter). Investigations were conducted to establish whether there are biological costs for tolerance to heavy metals in Anopheles gambiae Giles sensu stricto and to assess the potential impact of heavy metal pollution on mosquito ecology. Anopheles gambiae s.s. were selected for cadmium, copper or lead tolerance through chronic exposure of immature stages to solutions of the metals for three successive generations. Biological costs were assessed in the fourth generation by horizontal life table analysis. Tolerance in larvae to cadmium (as cadmium chloride, CdCl(2)), copper [as copper II nitrate hydrate, Cu(NO(3))(2) 2.5 H(2)O] and lead [as lead II nitrate, Pb(NO(3))(2)], monitored by changes in LC(50) concentrations of the metals, changed from 6.07 microg/L, 12.42 microg/L and 493.32 microg/L to 4.45 microg/L, 25.02 microg/L and 516.69 microg/L, respectively, after three generations of exposure. The metal-selected strains had a significantly lower magnitude of egg viability, larval and pupal survivorship, adult emergence, fecundity and net reproductive rate than the control strain. The population doubling times were significantly longer and the instantaneous birth rates lower in most metal-selected strains relative to the control strain. Our results suggest that although An. gambiae s.s. displays the potential to develop tolerance to heavy metals, particularly copper, this may occur at a significant biological cost, which can adversely affect its ecological fitness.

  9. Anopheles ziemanni a locally important malaria vector in Ndop health district, north west region of Cameroon

    PubMed Central

    2014-01-01

    Background Malaria transmission in Cameroon is mediated by a plethora of vectors that are heterogeneously distributed across the country depending on the biotope. To effectively guide malaria control operations, regular update on the role of local Anopheles species is essential. Therefore, an entomological survey was conducted between August 2010 and May 2011 to evaluate the role of the local anopheline population in malaria transmission in three villages of the Ndop health district in the northwest region of Cameroon where malaria is holoendemic, as a means to acquiring evidence based data for improved vector intervention. Methods Mosquitoes were sampled both indoor and outdoor for four consecutive nights in each locality during each month of survey. Sampling was done by the human landing catch method on volunteers. Anopheles species were identified morphologically and their ovaries randomly dissected for parity determination. Infection with Plasmodium falciparum was detected by Circumsporozoite protein ELISA. Members of An. gambiae complex were further identified to molecular level by PCR and RFLP PCR. Results An. ziemanni was the main malaria vector and whether outdoor or indoor. The man biting rate for the vectors ranged from 6.75 to 8.29 bites per person per night (b/p/n). The entomological inoculation rate for this vector species was 0.0278 infectious bites per person per night (ib/p/n) in Mbapishi, 0.034 ib/p/n in Mbafuh, and 0.063 ib/p/n in Backyit. These were by far greater than that for An. gambiae. No difference was observed in the parity rate of these two vectors. PCR analysis revealed the presence of only An. colluzzi (M- form). Conclusions An. ziemanni is an important local malaria vector in Ndop health district. The findings provide useful baseline information on the anopheles species composition, their distribution and role in malaria transmission that would guide the implementation of integrated vector management strategies in the locality. PMID

  10. PCR detection of malaria parasites in desiccated Anopheles mosquitoes is uninhibited by storage time and temperature

    PubMed Central

    2012-01-01

    Background Reliable methods to preserve mosquito vectors for malaria studies are necessary for detecting Plasmodium parasites. In field settings, however, maintaining a cold chain of storage from the time of collection until laboratory processing, or accessing other reliable means of sample preservation is often logistically impractical or cost prohibitive. As the Plasmodium infection rate of Anopheles mosquitoes is a central component of the entomological inoculation rate and other indicators of transmission intensity, storage conditions that affect pathogen detection may bias malaria surveillance indicators. This study investigated the effect of storage time and temperature on the ability to detect Plasmodium parasites in desiccated Anopheles mosquitoes by real-time polymerase chain reaction (PCR). Methods Laboratory-infected Anopheles stephensi mosquitoes were chloroform-killed and stored over desiccant for 0, 1, 3, and 6 months while being held at four different temperatures: 28, 37, -20 and -80°C. The detection of Plasmodium DNA was evaluated by real-time PCR amplification of a 111 base pair region of block 4 of the merozoite surface protein. Results Varying the storage time and temperature of desiccated mosquitoes did not impact the sensitivity of parasite detection. A two-way factorial analysis of variance suggested that storage time and temperature were not associated with a loss in the ability to detect parasites. Storage of samples at 28°C resulted in a significant increase in the ability to detect parasite DNA, though no other positive associations were observed between the experimental storage treatments and PCR amplification. Conclusions Cold chain maintenance of desiccated mosquito samples is not necessary for real-time PCR detection of parasite DNA. Though field-collected mosquitoes may be subjected to variable conditions prior to molecular processing, the storage of samples over an inexpensive and logistically accessible desiccant will likely

  11. Intragenomic rDNA ITS2 Variation in the Neotropical Anopheles (Nyssorhynchus) albitarsis Complex (Diptera: Culicidae)

    DTIC Science & Technology

    2006-12-07

    However, in Allopb,/er, there are examples of rONA intragenomic variation (\\X’ilkerson et al. 2004; Fairley et al. 2005), but its prevalence and...Anopheles species (Onyabe and Conn 1999; Wilkerson et al. 2004; Fairley et aI. 200S) and in other mos- quitoes in subfamily Culicinae (Black et a!. 1989...DNA 1TS2 sequences. J :-.led Entomo!’ 33:109-116. Dover GA. 1982. Molecular dri"e: a cnhesive mode of species evolution. Nature. 299:111-117. Fairley

  12. Plasmodium vivax sporozoite rates from Anopheles albimanus in southern Chiapas, Mexico.

    PubMed

    Ramsey, J M; Salinas, E; Bown, D N; Rodriguez, M H

    1994-06-01

    Anopheles albimanus mosquitoes were collected from August 1984 to November 1987 on intra- and peridomicile human bait in Rancheria El Gancho, Chiapas, Mexico. The mosquitoes were desiccated and stored in silicon chambers from 3 mo to 3 yr post-collection prior to being assayed using a direct enzyme-linked immunosorbent assay to detect Plasmodium vivax predominant-type sporozoite protein. Peridomicile-collected mosquitoes had a 10-fold higher sporozoite rate than those collected indoors, but only the latter correlate significantly with the seasonal human parasite index. Mosquito sporozoite burden was also significantly higher in the peridomicile-collected population.

  13. Laboratory oviposition, fecundity and egg hatching ability of colonized Anopheles albimanus from southwestern Mexico.

    PubMed

    Ramsey, J M; Salinas, E; Lopez, J R; del Angel-Cabañas, G; Martinez, L; Bown, D N

    1988-12-01

    Fecundity, oviposition patterns and egg hatching characteristics were studied in two colonies of Anopheles albimanus isolated from the Pacific coast of southern Mexico. Fecundity was inversely proportional to the cage space available to the female and was influenced by the bloodmeal source, feeding method and previous feeding history. The length of the gonotrophic cycle decreased with succeeding experience from a mean 6.6 in the first to 2.6 days for the fifth cycle. Oviposition timing was also dependent on availability of oviposition substrate. Hatching success of eggs increased significantly when the oviposition site was witheld until 48 hr post-bloodmeal.

  14. Small-scale field evaluation of the monomolecular surface film 'Arosurf MSF' against Anopheles arabiensis Patton.

    PubMed

    Karanja, D M; Githeko, A K; Vulule, J M

    1994-04-01

    A field trial was conducted to test the insecticidal action of the monolayer surface film 'Arosurf MSF' applied by knapsack sprayers, against larvae and pupae of Anopheles arabiensis Patton in a rice irrigation scheme in Western Kenya. Larval and pupal densities and the number of emerging adults were determined by dipping and emergence cages respectively. Application of the monolayer by knapsack sprayers provided good coverage. There were high daily mortalities of the fourth instar larvae, with no adult emergence from 'Arosurf MSF' treated plots compared to lower fourth instar mortalities and continuous adult emergence from untreated control plots, indicating the potential of the monolayer for control of An. arabiensis mosquitoes in rice fields.

  15. Habitat discrimination by gravid Anopheles gambiae sensu lato – a push-pull system

    PubMed Central

    2014-01-01

    Background The non-random distribution of anopheline larvae in natural habitats suggests that gravid females discriminate between habitats of different quality. Whilst physical and chemical cues used by Culex and Aedes vector mosquitoes for selecting an oviposition site have been extensively studied, those for Anopheles remain poorly explored. Here the habitat selection by Anopheles gambiae sensu lato (s.l.), the principal African malaria vector, was investigated when presented with a choice of two infusions made from rabbit food pellets, or soil. Methods Natural colonization and larval survival was evaluated in artificial ponds filled randomly with either infusion. Dual-choice, egg-count bioassays evaluated the responses of caged gravid females to (1) two- to six-day old infusions versus lake water; (2) autoclaved versus non-autoclaved soil infusions; and assessed (3) the olfactory memory of gravid females conditioned in pellet infusion as larvae. Results Wild Anopheles exclusively colonized ponds with soil infusion and avoided those with pellet infusion. When the individual infusions were tested in comparison with lake water, caged An. gambiae sensu stricto (s.s.) showed a dose response: females increasingly avoided the pellet infusion with increasing infusion age (six-day versus lake water: odds ratio (OR) 0.22; 95% confidence interval (CI) 0.1-0.5) and showed increasing preference to lay eggs as soil infusion age increased (six-day versus lake water: OR 2.1; 95% CI 1.4-3.3). Larvae survived in soil infusions equally well as in lake water but died in pellet infusions. Anopheles gambiae s.s. preferred to lay eggs in the non-autoclaved soil (OR 2.6; 95% CI 1.8-3.7) compared with autoclaved soil. There was no change in the avoidance of pellet infusion by individuals reared in the infusion compared with those reared in lake water. Conclusion Wild and caged An. gambiae s.l. females discriminate between potential aquatic habitats for oviposition. These choices benefit

  16. Insertion polymorphisms of SINE200 retrotransposons within speciation islands of Anopheles gambiae molecular forms

    PubMed Central

    Santolamazza, Federica; Mancini, Emiliano; Simard, Frédéric; Qi, Yumin; Tu, Zhijian; della Torre, Alessandra

    2008-01-01

    Background SINEs (Short INterspersed Elements) are homoplasy-free and co-dominant genetic markers which are considered to represent useful tools for population genetic studies, and could help clarifying the speciation processes ongoing within the major malaria vector in Africa, Anopheles gambiae s.s. Here, we report the results of the analysis of the insertion polymorphism of a nearly 200 bp-long SINE (SINE200) within genome areas of high differentiation (i.e. "speciation islands") of M and S A. gambiae molecular forms. Methods A SINE-PCR approach was carried out on thirteen SINE200 insertions in M and S females collected along the whole range of distribution of A. gambiae s.s. in sub-Saharan Africa. Ten specimens each for Anopheles arabiensis, Anopheles melas, Anopheles quadriannulatus A and 15 M/S hybrids from laboratory crosses were also analysed. Results Eight loci were successfully amplified and were found to be specific for A. gambiae s.s.: 5 on 2L chromosome and one on X chromosome resulted monomorphic, while two loci positioned respectively on 2R (i.e. S200 2R12D) and X (i.e. S200 X6.1) chromosomes were found to be polymorphic. S200 2R12D was homozygote for the insertion in most S-form samples, while intermediate levels of polymorphism were shown in M-form, resulting in an overall high degree of genetic differentiation between molecular forms (Fst = 0.46 p < 0.001) and within M-form (Fst = 0.46 p < 0.001). The insertion of S200 X6.1 was found to be fixed in all M- and absent in all S-specimens. This led to develop a novel easy-to-use PCR approach to straightforwardly identify A. gambiae molecular forms. This novel approach allows to overcome the constraints associated with markers on the rDNA region commonly used for M and S identification. In fact, it is based on a single copy and irreversible SINE200 insertion and, thus, is not subjected to peculiar evolutionary patterns affecting rDNA markers, e.g. incomplete homogenization of the arrays through

  17. Identification of the sibling species of the Anopheles maculipennis complex by heteroduplex analysis.

    PubMed

    Romi, R; Boccolini, D; Di Luca, M; La Rosa, G; Marinucci, M

    2000-10-01

    The group of anopheline mosquitoes referred to as 'Anopheles maculipennis complex' includes the most important malaria vectors of the Palearctic Western region. The species belonging to this complex, however, are difficult or impossible to distinguish by morphological characters. To differentiate sibling palearctic species belonging to this complex, interspecific differences in the ITS2 sequences were used to set up a rapid and sensitive diagnostic tool based on heteroduplex analysis. The relative heteroduplex mobility allowed the following seven species to be readily distinguished: An. atroparvus, An. labranchiae, An. maculipennis s.s. , An. martinius, An melanoon, An. messeae and An. sacharovi.

  18. Chemical composition and insecticidal activity of plant essential oils from Benin against Anopheles gambiae (Giles)

    PubMed Central

    2013-01-01

    Background Insecticide resistance in sub-Saharan Africa and especially in Benin is a major public health issue hindering the control of the malaria vectors. Each Anopheles species has developed a resistance to one or several classes of the insecticides currently in use in the field. Therefore, it is urgent to find alternative compounds to conquer the vector. In this study, the efficacies of essential oils of nine plant species, which are traditionally used to avoid mosquito bites in Benin, were investigated. Methods Essential oils of nine plant species were extracted by hydrodistillation, and their chemical compositions were identified by GC-MS. These oils were tested on susceptible “kisumu” and resistant “ladji-Cotonou” strains of Anopheles gambiae, following WHO test procedures for insecticide resistance monitoring in malaria vector mosquitoes. Results Different chemical compositions were obtained from the essential oils of the plant species. The major constituents identified were as follows: neral and geranial for Cymbopogon citratus, Z-carveol, E-p-mentha-1(7),8-dien-2-ol and E-p-mentha-2,8-dienol for Cymbopogon giganteus, piperitone for Cymbopogon schoenanthus, citronellal and citronellol for Eucalyptus citriodora, p-cymene, caryophyllene oxide and spathulenol for Eucalyptus tereticornis, 3-tetradecanone for Cochlospermum tinctorium and Cochlospermum planchonii, methyl salicylate for Securidaca longepedunculata and ascaridole for Chenopodium ambrosioides. The diagnostic dose was 0.77% for C. citratus, 2.80% for E. tereticornis, 3.37% for E. citriodora, 4.26% for C. ambrosioides, 5.48% for C. schoenanthus and 7.36% for C. giganteus. The highest diagnostic doses were obtained with S. longepedunculata (9.84%), C. tinctorium (11.56%) and C. planchonii (15.22%), compared to permethrin 0.75%. A. gambiae cotonou, which is resistant to pyrethroids, showed significant tolerance to essential oils from C. tinctorium and S. longepedunculata as expected but was

  19. 3D tracking of mating events in wild swarms of the malaria mosquito Anopheles gambiae.

    PubMed

    Butail, Sachit; Manoukis, Nicholas; Diallo, Moussa; Yaro, Alpha S; Dao, Adama; Traoré, Sekou F; Ribeiro, José M; Lehmann, Tovi; Paley, Derek A

    2011-01-01

    We describe an automated tracking system that allows us to reconstruct the 3D kinematics of individual mosquitoes in swarms of Anopheles gambiae. The inputs to the tracking system are video streams recorded from a stereo camera system. The tracker uses a two-pass procedure to automatically localize and track mosquitoes within the swarm. A human-in-the-loop step verifies the estimates and connects broken tracks. The tracker performance is illustrated using footage of mating events filmed in Mali in August 2010.

  20. Spatial Patterns of Plasmodium falciparum Clinical Incidence, Asymptomatic Parasite Carriage and Anopheles Density in Two Villages in Mali.

    PubMed

    Sissoko, Mahamadou S; van den Hoogen, Lotus L; Samake, Yacouba; Tapily, Amadou; Diarra, Adama Z; Coulibaly, Maimouna; Bouare, Madama; Gaudart, Jean; Knight, Philip; Sauerwein, Robert W; Takken, Willem; Bousema, Teun; Doumbo, Ogobara K

    2015-10-01

    Heterogeneity in malaria exposure is most readily recognized in areas with low-transmission patterns. By comparison, little research has been done on spatial patterns in malaria exposure in high-endemic settings. We determined the spatial clustering of clinical malaria incidence, asymptomatic parasite carriage, and Anopheles density in two villages in Mali exposed to low- and mesoendemic-malaria transmission. In the two study areas that were < 1 km(2) in size, we observed evidence for spatial clustering of Anopheles densities or malaria parasite carriage during the dry season. Anopheles density and malaria prevalence appeared associated in some of our detected hotspots. However, many households with high parasite prevalence or high Anopheles densities were located outside the identified hotspots. Our findings indicate that within small villages exposed to low- or mesoendemic-malaria transmission, spatial patterns in mosquito densities and parasite carriage are best detected in the dry season. Considering the high prevalence of parasite carriage outside detected hotspots, the suitability of the area for targeting control efforts to households or areas of more intense malaria transmission may be limited.

  1. Draft Genome Sequences of Two Strains of Serratia spp. from the Midgut of the Malaria Mosquito Anopheles gambiae

    PubMed Central

    Pei, Dong; Hill-Clemons, Casey; Carissimo, Guillaume; Yu, Wanqin; Vernick, Kenneth D.

    2015-01-01

    Here, we report the annotated draft genome sequences of two strains of Serratia spp., Ag1 and Ag2, isolated from the midgut of two different strains of Anopheles gambiae. The genomes of these two strains are almost identical. PMID:25767231

  2. Genome Sequence of Elizabethkingia anophelis Strain EaAs1, Isolated from the Asian Malaria Mosquito Anopheles stephensi.

    PubMed

    Raygoza Garay, Juan Antonio; Hughes, Grant L; Koundal, Vikas; Rasgon, Jason L; Mwangi, Michael M

    2016-03-10

    We sequenced the genome of a strain of the Gram-negative bacterial species Elizabethkingia anophelis, which is an important component of the Anopheles mosquito microbiome. This genome sequence will add to the list of resources used to examine host-microbe interactions in mosquitoes.

  3. Genome Sequence of Stenotrophomonas maltophilia Strain SmAs1, Isolated From the Asian Malaria Mosquito Anopheles stephensi

    PubMed Central

    Hughes, Grant L.; Raygoza Garay, Juan Antonio; Koundal, Vikas; Mwangi, Michael M.

    2016-01-01

    An isolate of Stenotrophomonas maltophilia was cultured from the Asian malaria vector Anopheles stephensi. Here, we present the annotated draft genome sequence of this S. maltophilia strain. This genomic resource will facilitate further characterization of bacteria associated with mosquitoes. PMID:26966198

  4. Habitat suitability of Anopheles vector species and association with human malaria in the Atlantic Forest in south-eastern Brazil.

    PubMed

    Laporta, Gabriel Zorello; Ramos, Daniel Garkauskas; Ribeiro, Milton Cezar; Sallum, Maria Anice Mureb

    2011-08-01

    Every year, autochthonous cases of Plasmodium vivax malaria occur in low-endemicity areas of Vale do Ribeira in the south-eastern part of the Atlantic Forest, state of São Paulo, where Anopheles cruzii and Anopheles bellator are considered the primary vectors. However, other species in the subgenus Nyssorhynchus of Anopheles (e.g., Anopheles marajoara) are abundant and may participate in the dynamics of malarial transmission in that region. The objectives of the present study were to assess the spatial distribution of An. cruzii, An. bellator and An. marajoara and to associate the presence of these species with malaria cases in the municipalities of the Vale do Ribeira. Potential habitat suitability modelling was applied to determine both the spatial distribution of An. cruzii, An. bellator and An. marajoara and to establish the density of each species. Poisson regression was utilized to associate malaria cases with estimated vector densities. As a result, An. cruzii was correlated with the forested slopes of the Serra do Mar, An. bellator with the coastal plain and An. marajoara with the deforested areas. Moreover, both An. marajoara and An. cruzii were positively associated with malaria cases. Considering that An. marajoara was demonstrated to be a primary vector of human Plasmodium in the rural areas of the state of Amapá, more attention should be given to the species in the deforested areas of the Atlantic Forest, where it might be a secondary vector.

  5. Notes and Redescriptions of Some Anopheles Series Arribalzagia Holotypes (Diptera: Culicidae) in the British Museum (Natural History)

    DTIC Science & Technology

    1988-10-12

    Ev- ans La Cabrero Estado Carabobo 192 1 Dr. M Nunez Tovar”; “Holotype of Anopheles venezuelae Evans det. J . Chainey 1975.” Condition of specimen...Anophelines of the Amazon Med. Parasitol. 17: 101-l 11. Valley. Proc. Entomol. Sot. Wash. 35: 117-133. Reid, J . A. and K. L. Knight. 196 1. Classification

  6. Larvicidal and repellent activity of Vetiveria zizaniodes (Poaceae) essential oil against the malaria vector Anopheles stephensi (Liston) (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Essential oil extracted by steam distillation of Vetiveria zizanioides (L.) Nash (Poaceae) was evaluated for larvicidal and adult repellent activity against the malaria vector Anopheles stephensi (Liston). Median lethal concentrations (LC50) at 24 h post treatment for instars 1-4 were, respectively,...

  7. Toxicity of six plant extracts and two pyridine alkaloids from Ricinus communis against the malaria vector Anopheles gambiae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The African malaria vector, Anopheles gambiae s.s., is known to feed selectively on certain plants for sugar sources. However, the adaptive significance of this behavior especially on how the extracts of such plants impact on the fitness of this vector has not been explored. This study determined th...

  8. The ecology of Anopheles mosquitoes under climate change: case studies from the effects of deforestation in East African highlands.

    PubMed

    Afrane, Yaw A; Githeko, Andrew K; Yan, Guiyun

    2012-02-01

    Climate change is expected to lead to latitudinal and altitudinal temperature increases. High-elevation regions such as the highlands of Africa and those that have temperate climate are most likely to be affected. The highlands of Africa generally exhibit low ambient temperatures. This restricts the distribution of Anopheles mosquitoes, the vectors of malaria, filariasis, and O'nyong'nyong fever. The development and survival of larval and adult mosquitoes are temperature dependent, as are mosquito biting frequency and pathogen development rate. Given that various Anopheles species are adapted to different climatic conditions, changes in climate could lead to changes in species composition in an area that may change the dynamics of mosquito-borne disease transmission. It is important to consider the effect of climate change on rainfall, which is critical to the formation and persistence of mosquito breeding sites. In addition, environmental changes such as deforestation could increase local temperatures in the highlands; this could enhance the vectorial capacity of the Anopheles. These experimental data will be invaluable in facilitating the understanding of the impact of climate change on Anopheles.

  9. Electrophysiological responses of gustatory receptor neurons on the labella of the common malaria mosquito Anopheles quadrimaculatus Say (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We recorded electrical responses from sensory cells associated with gustatory sensilla on the labella of female Anopheles quadrimaculatus to salt, sucrose, quinine (a feeding deterrent) and the insect repellent, N,N-diethyl-3-methylbenzamide (DEET). A salt-sensitive cell responded to increasing con...

  10. Brazilian mosquito (Diptera: Culicidae) fauna: I. Anopheles species from Porto Velho, Rondônia state, western Amazon, Brazil.

    PubMed

    Morais, Sirlei Antunes; Urbinatti, Paulo Roberto; Sallum, Maria Anice Mureb; Kuniy, Adriana Akemi; Moresco, Gilberto Gilmar; Fernandes, Aristides; Nagaki, Sandra Sayuri; Natal, Delsio

    2012-12-01

    This study contributes to knowledge of Anopheles species, including vectors of Plasmodium from the western Brazilian Amazon in Porto Velho, Rondônia State. The sampling area has undergone substantial environmental changes as a consequence of agricultural and hydroelectric projects, which have caused intensive deforestation and favored habitats for some mosquito species. The purpose of this study was to diagnose the occurrence of anopheline species from collections in three locations along an electric-power transmission line. Each locality was sampled three times from 2010 to 2011. The principal adult mosquitoes captured in Shannon trap were Anopheles darlingi, An. triannulatus, An. nuneztovari l.s., An.gilesi and An. costai. In addition, larvae were collected in ground breeding sites for Anopheles braziliensis, An. triannulatus, An. darlingi, An. deaneorum, An. marajoara, An. peryassui, An. nuneztovari l.s. and An. oswaldoi-konderi. Anopheles darlingi was the most common mosquito in the region. We discuss Culicidae systematics, fauna distribution, and aspects of malaria in altered habitats of the western Amazon.

  11. Genome Sequence of Elizabethkingia anophelis Strain EaAs1, Isolated from the Asian Malaria Mosquito Anopheles stephensi

    PubMed Central

    Raygoza Garay, Juan Antonio; Hughes, Grant L.; Koundal, Vikas; Mwangi, Michael M.

    2016-01-01

    We sequenced the genome of a strain of the Gram-negative bacterial species Elizabethkingia anophelis, which is an important component of the Anopheles mosquito microbiome. This genome sequence will add to the list of resources used to examine host-microbe interactions in mosquitoes. PMID:26966196

  12. Pesticide susceptibility status of Anopheles mosquitoes in four flood-affected districts of South Punjab, Pakistan.

    PubMed

    Rathor, Hamayun Rashid; Nadeem, Ghazala; Khan, Imtinan Akram

    2013-01-01

    Recent floods drastically increased the burden of disease, in particular the incidence of malaria, in the southern districts of the Punjab province in Pakistan. Control of malaria vector mosquitoes in these districts requires the adoption of an appropriate evidence-based policy on the use of pesticides, and having the latest information on the insecticide resistance status of malaria vector mosquitoes is essential for designing effective disease prevention policy. Using World Health Organization (WHO) test kits, the present study utilized papers impregnated with DDT, malathion, deltamethrin, lambda-cyhalothrin, and permethrin, to determine the insecticide susceptibility/resistance status of malaria vector mosquitoes in four flood-affected districts. The test results showed that both Anopheles stephensi and Anopheles culicifacies remained resistant to DDT and malathion. Tests with three commonly used pyrethroids, permethrin, lambda-cyhalothrin, and deltamethrin, detected resistance in the majority of cases, but in a number of localities mortalities with these three pyrethroids ranged from 80-97% and were therefore placed under verification-required status. This status indicates the presence of susceptible individuals in these populations. These results suggest that if appropriate resistance management strategies are applied in these areas, then the development of high levels of resistance can still be prevented or slowed. This study forms an important evidence base for the strategic planning of vector control in the four flood-affected districts.

  13. Peculiar liquid-feeding and pathogen transmission behavior of Aedes togoi and comparison with Anopheles sinensis

    NASA Astrophysics Data System (ADS)

    Lee, Sang Joon; Kang, Dooho; Lee, Seung Chul; Ha, Young-Ran

    2016-02-01

    Female mosquitoes transmit various diseases as vectors during liquid-feeding. Identifying the determinants of vector efficiency is a major scientific challenge in establishing strategies against these diseases. Infection rate and transmission efficiency are interconnected with the mosquito-induced liquid-feeding flow as main indexes of vector efficiency. However, the relationship between liquid-feeding characteristics and pathogen remains poorly understood. The liquid-feeding behavior of Aedes togoi and Anopheles sinensis was comparatively investigated in conjunction with vector efficiency via micro-particle image velocimetry. The flow rates and ratio of the ejection volume of Aedes togoi were markedly higher than those of Anophels sinensis. These differences would influence pathogen re-ingestion. Wall shear stresses of these mosquito species were also clearly discriminatory affecting the infective rates of vector-borne diseases. The variations in volume of two pump chambers and diameter of proboscis of these mosquito species were compared to determine the differences in the liquid-feeding process. Liquid-feeding characteristics influence vector efficiency; hence, this study can elucidate the vector efficiency of mosquitoes and the vector-pathogen interactions and contribute to the development of strategies against vector-borne diseases.

  14. A natural Anopheles-associated Penicillium chrysogenum enhances mosquito susceptibility to Plasmodium infection

    PubMed Central

    Angleró-Rodríguez, Yesseinia I.; Blumberg, Benjamin J.; Dong, Yuemei; Sandiford, Simone L.; Pike, Andrew; Clayton, April M.; Dimopoulos, George

    2016-01-01

    Whereas studies have extensively examined the ability of bacteria to influence Plasmodium infection in the mosquito, the tripartite interactions between non-entomopathogenic fungi, mosquitoes, and Plasmodium parasites remain largely uncharacterized. Here we report the isolation of a common mosquito-associated ascomycete fungus, Penicillium chrysogenum, from the midgut of field-caught Anopheles mosquitoes. Although the presence of Pe. chrysogenum in the Anopheles gambiae midgut does not affect mosquito survival, it renders the mosquito significantly more susceptible to Plasmodium infection through a secreted heat-stable factor. We further provide evidence that the mechanism of the fungus-mediated modulation of mosquito susceptibility to Plasmodium involves an upregulation of the insect’s ornithine decarboxylase gene, which sequesters arginine for polyamine biosynthesis. Arginine plays an important role in the mosquito’s anti-Plasmodium defense as a substrate of nitric oxide production, and its availability therefore has a direct impact on the mosquito’s susceptibility to the parasite. While this type of immunomodulatory mechanism has already been demonstrated in other host-pathogen interaction systems, this is the first report of a mosquito-associated fungus that can suppress the mosquito’s innate immune system in a way that would favor Plasmodium infection and possibly malaria transmission. PMID:27678168

  15. Landscape and land cover factors influence the presence of Aedes and Anopheles larvae.

    PubMed

    Vanwambeke, Sophie O; Somboon, Pradya; Harbach, Ralph E; Isenstadt, Mark; Lambin, Eric F; Walton, Catherine; Butlin, Roger K

    2007-01-01

    The objective of this study was to test for associations between land cover data and the presence of mosquito larvae of the genera Aedes Meigen and Anopheles Meigen in northern Thailand at the landscape scale. These associations were compared with associations between larval habitat variables and the presence of mosquito larvae at a finer spatial scale. Collection data for the larvae of one Aedes species and three species-groups of Anopheles, all of which are involved in pathogen transmission, were used. A variety of northern Thai landscapes were included, such as upland villages, lowland villages and peri-urban areas. Logistic regression was used to evaluate associations. Generally, land cover and landscape variables explained the presence of larvae as well as did larval habitat variables. Results were best for species/species-groups with specific habitat requirements. Land cover variables act as proxies for the types of habitat available and their attributes. Good knowledge of the habitat requirements of the immature stages of mosquitoes is necessary for interpreting the effects of land cover.

  16. Genetic and phenotypic variation of the malaria vector Anopheles atroparvus in southern Europe

    PubMed Central

    2011-01-01

    Background There is a growing concern that global climate change will affect the potential for pathogen transmission by insect species that are vectors of human diseases. One of these species is the former European malaria vector, Anopheles atroparvus. Levels of population differentiation of An. atroparvus from southern Europe were characterized as a first attempt to elucidate patterns of population structure of this former malaria vector. Results are discussed in light of a hypothetical situation of re-establishment of malaria transmission. Methods Genetic and phenotypic variation was analysed in nine mosquito samples collected from five European countries, using eight microsatellite loci and geometric morphometrics on 21 wing landmarks. Results Levels of genetic diversity were comparable to those reported for tropical malaria vectors. Low levels of genetic (0.004 Anopheles maculipennis s.s. Differentiation between sibling species was not so evident at the phenotype level. Conclusions Levels of population differentiation within An. atroparvus were low and not correlated with geographic distance or with putative physical barriers to gene flow (Alps and Pyrenées). While these results may suggest considerable levels of gene flow, other explanations such as the effect of historical population perturbations can also be hypothesized. PMID:21223582

  17. Bionomic Aspects of the Anopheles subpictus Species Complex in Sri Lanka

    PubMed Central

    Jude, Pavillupillai J.; Ramasamy, Ranjan; Surendran, Sinnathamby N.

    2014-01-01

    Anopheles subpictus Grassi s.l. (Diptera: Culicidae) functions as a secondary malaria vector to Anopheles culicifacies Giles s.l. (Diptera: Culicidae) in Sri Lanka. The taxon A. subpictus is reported to exist as a species complex comprising four sibling species (A–D) that can be differentiated through polytene chromosome banding patterns and stage-specific morphometric traits in India. Based on the morphological characteristics described for the Indian Subpictus Complex, the presence of all four sibling species has been described in Sri Lanka. As sibling species show distinct bio-ecological characteristics that are important for devising appropriate vector control measures, a study was carried out in six districts in the dry zone of Sri Lanka. The results confirm the presence of all four sibling species, with species C predominating in inland areas and species B in coastal areas. Species C and D were indoor-resting and indoor-feeding, while species B was outdoor-resting with no significant preference for indoor- or outdoor-resting. Species B showed distinct morphological variation in the ornamentation of wings and palpi. Blood meal analysis revealed that species B, C, and D can feed on humans as well as cattle. The differential bio-ecological traits shown by the members of the Subpictus Complex are important for developing appropriate vector control measures in Sri Lanka. PMID:25205254

  18. Genomic Analysis of Detoxification Supergene Families in the Mosquito Anopheles sinensis.

    PubMed

    Zhou, Dan; Liu, Xianmiao; Sun, Yan; Ma, Lei; Shen, Bo; Zhu, Changliang

    2015-01-01

    Anopheles sinensis is an important malaria vector in China and other Southeast Asian countries, and the emergence of insecticide resistance in this mosquito poses a serious threat to the efficacy of malaria control programs. The recently published An. sinensis genome and transcriptome provide an opportunity to understand the molecular mechanisms of insecticide resistance. Analysis of the An. sinensis genome revealed 174 detoxification genes, including 93 cytochrome P450s (P450s), 31 glutathione-S-transferases (GSTs), and 50 choline/carboxylesterases (CCEs). The gene number was similar to that in An. gambiae, but represented a decrease of 29% and 42% compared with Aedes aegypti and Culex quinquefasciatus, respectively. The considerable contraction in gene number in Anopheles mosquitoes mainly occurred in two detoxification supergene families, P450s and CCEs. The available An. sinensis transcriptome was also re-analyzed to further identify key resistance-associated detoxification genes. Among 174 detoxification genes, 124 (71%) were detected. Several candidate genes overexpressed in a deltamethrin-resistant strain (DR-strain) were identified as belonging to the CYP4 or CYP6 family of P450s and the Delta GST class. These generated data provide a basis for identifying the resistance-associated genes of An. sinensis at the molecular level.

  19. Geographic distribution, evolution, and disease importance of species within the Neotropical Anopheles albitarsis Group (Diptera, Culicidae)

    PubMed Central

    Linton, Yvonne-Marie; Ruiz-Lopez, J. Freddy; Conn, Jan E.; Sallum, Maria Anice M.; Póvoa, Marinete M.; Bergo, Eduardo S.; Oliveira, Tatiane M. P.; Sucupira, Izis; Wilkerson, Richard C.

    2015-01-01

    The Anopheles albitarsis group of mosquitoes comprises eight recognized species and one mitochondrial lineage. Our knowledge of malaria vectorial importance and the distribution and evolution of these taxa is incomplete. We constructed ecological niche models (ENMs) for these taxa and used hypothesized phylogenetic relationships and ENMs to investigate environmental and ecological divergence associated with speciation events. Two major clades were identified, one north (Clade 1) and one south (Clade 2) of the Amazon River that likely is or was a barrier to mosquito movement. Clade 1 species occur more often in higher average temperature locations than Clade 2 species, and taxon splits within Clade 1 corresponded with a greater divergence of variables related to precipitation than was the case within Clade 2. Comparison of the ecological profiles of sympatric species and sister species support the idea that phylogenetic proximity is related to ecological similarity. Anopheles albitarsis I, An. janconnae, and An. marajoara ENMs had the highest percentage of their predicted suitable habitat overlapping distribution models of Plasmodium falciparum and P. vivax, and warrant additional studies of the transmission potential of these species. Phylogenetic proximity may be related to malaria vectorial importance within the Albitarsis Group. PMID:24820570

  20. Indirect evidence that agricultural pesticides select for insecticide resistance in the malaria vector Anopheles gambiae.

    PubMed

    Luc, Djogbénou S; Benoit, Assogba; Laurette, Djossou; Michel, Makoutode

    2016-06-01

    We investigated the possible relationship between the agricultural use of insecticides and the emergence of insecticide resistance. Bioassays were conducted using simulated mosquito larval habitats and well known Anopheles gambiae strains. Soil samples were collected from vegetable production areas in Benin, including one site with insecticide use, one site where insecticides had not been used for two months, and a third where insecticides had not been used. Pupation and emergence rates were very low in pyrethroid-susceptible strains when exposed to soil that had been recently exposed to insecticides. Pupation and emergence rates in strains with the kdr mutation alone or both the kdr and Ace-1 mutations were much higher. Overall, strains with the kdr mutation survived at higher rates compared to that without kdr mutation. Although this study is observational, we provide indirect evidence indicating that soils from agricultural areas contain insecticide residues that can play a role in the emergence of insecticide resistance in Anopheles. This aspect should be taken into account to better utilize the insecticide in the context of integrated pest management programs.

  1. A proteogenomic analysis of Anopheles gambiae using high-resolution Fourier transform mass spectrometry.

    PubMed

    Chaerkady, Raghothama; Kelkar, Dhanashree S; Muthusamy, Babylakshmi; Kandasamy, Kumaran; Dwivedi, Sutopa B; Sahasrabuddhe, Nandini A; Kim, Min-Sik; Renuse, Santosh; Pinto, Sneha M; Sharma, Rakesh; Pawar, Harsh; Sekhar, Nirujogi Raja; Mohanty, Ajeet Kumar; Getnet, Derese; Yang, Yi; Zhong, Jun; Dash, Aditya P; MacCallum, Robert M; Delanghe, Bernard; Mlambo, Godfree; Kumar, Ashwani; Keshava Prasad, T S; Okulate, Mobolaji; Kumar, Nirbhay; Pandey, Akhilesh

    2011-11-01

    Anopheles gambiae is a major mosquito vector responsible for malaria transmission, whose genome sequence was reported in 2002. Genome annotation is a continuing effort, and many of the approximately 13,000 genes listed in VectorBase for Anopheles gambiae are predictions that have still not been validated by any other method. To identify protein-coding genes of An. gambiae based on its genomic sequence, we carried out a deep proteomic analysis using high-resolution Fourier transform mass spectrometry for both precursor and fragment ions. Based on peptide evidence, we were able to support or correct more than 6000 gene annotations including 80 novel gene structures and about 500 translational start sites. An additional validation by RT-PCR and cDNA sequencing was successfully performed for 105 selected genes. Our proteogenomic analysis led to the identification of 2682 genome search-specific peptides. Numerous cases of encoded proteins were documented in regions annotated as intergenic, introns, or untranslated regions. Using a database created to contain potential splice sites, we also identified 35 novel splice junctions. This is a first report to annotate the An. gambiae genome using high-accuracy mass spectrometry data as a complementary technology for genome annotation.

  2. Mosquito larvicidal activity of seaweeds extracts against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus

    PubMed Central

    Ali, Mohamed Yacoob Syed; Ravikumar, Sundaram; Beula, Johanson Margaret

    2013-01-01

    Objective To identify the larvicidal activity of the seaweed extracts against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus Methods Seaweed extracts of Ulva lactuca, Caulerpa racemosa (C. racemosa), Sargassum microystum, Caulerpa scalpelliformis, Gracilaria corticata, Turbinaria decurrens, Turbinaria conoides and Caulerpa toxifolia were dissolved in DMSO to prepare a graded series of concentration. The test for the larvicidal effect of seaweeds against mosquitos larvae was conducted in accordance with the WHO standard method. Batches of 25 early 4th instar larvae of three mosquitoes were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (10-100 µg). Each experiment was conducted with triplicate with concurrent a control group. Results Among the seaweeds extract, C. racemosa showed toxicity against 4th instar larvae of Aedes aegypti, Culex quinquefasciatus, Anopheles stephensi with equivalent LC50 value (0.055 6±0.010 3) µg/mL, (0.067 5±0.136 0) µg/mL and (0.066 1±0.007 6) µg/mL, respectively. Conclusions The present study concluded that, the mosquito larvicidal property of C. racemosa might be the prospective alternative source to control the mosquitoes.

  3. Peculiar liquid-feeding and pathogen transmission behavior of Aedes togoi and comparison with Anopheles sinensis

    PubMed Central

    Lee, Sang Joon; Kang, Dooho; Lee, Seung Chul; Ha, Young-Ran

    2016-01-01

    Female mosquitoes transmit various diseases as vectors during liquid-feeding. Identifying the determinants of vector efficiency is a major scientific challenge in establishing strategies against these diseases. Infection rate and transmission efficiency are interconnected with the mosquito-induced liquid-feeding flow as main indexes of vector efficiency. However, the relationship between liquid-feeding characteristics and pathogen remains poorly understood. The liquid-feeding behavior of Aedes togoi and Anopheles sinensis was comparatively investigated in conjunction with vector efficiency via micro-particle image velocimetry. The flow rates and ratio of the ejection volume of Aedes togoi were markedly higher than those of Anophels sinensis. These differences would influence pathogen re-ingestion. Wall shear stresses of these mosquito species were also clearly discriminatory affecting the infective rates of vector-borne diseases. The variations in volume of two pump chambers and diameter of proboscis of these mosquito species were compared to determine the differences in the liquid-feeding process. Liquid-feeding characteristics influence vector efficiency; hence, this study can elucidate the vector efficiency of mosquitoes and the vector-pathogen interactions and contribute to the development of strategies against vector-borne diseases. PMID:26839008

  4. Sampling outdoor, resting Anopheles gambiae and other mosquitoes (Diptera: Culicidae) in western Kenya with clay pots.

    PubMed

    Odiere, M; Bayoh, M N; Gimnig, J; Vulule, J; Irungu, L; Walker, E

    2007-01-01

    Clay pots were analyzed as devices for sampling the outdoor resting fraction of Anopheles gambiae Giles (Diptera: Culicidae) and other mosquito species in a rural, western Kenya. Clay pots (Anopheles gambiae resting pots, herein AgREPOTs), outdoor pit shelters, indoor pyrethrum spray collections (PSC), and Colombian curtain exit traps were compared in collections done biweekly for nine intervals from April to June 2005 in 20 housing compounds. Of 10,517 mosquitoes sampled, 4,668 An. gambiae s.l. were sampled in total of which 63% were An. gambiae s.s. (46% female) and 37% were An. arabiensis (66% female). The clay pots were useful and practical for sampling both sexes of An. gambiae s.l. Additionally, 617 An. funestus (58% female) and 5,232 Culex spp. (males and females together) were collected. Temporal changes in abundance of An. gambiae s.l. were similarly revealed by all four sampling methods, indicating that the clay pots could be used as devices to quantify variation in mosquito population density. Dispersion patterns of the different species and sexes fit well the negative binomial distribution, indicating that the mosquitoes were aggregated in distribution. Aside from providing a useful sampling tool, the AgREPOT also may be useful as a delivery vehicle for insecticides or pathogens to males and females that enter and rest in them.

  5. Plasmodium vivax Sporozoite Production in Anopheles albimanus Mosquitoes for Vaccine Clinical Trials

    PubMed Central

    Solarte, Yezid; Manzano, María R.; Rocha, Leonardo; Hurtado, Hugo; James, Mark A.; Arévalo-Herrera, Myriam; Herrera, Sócrates

    2011-01-01

    Vaccine development for Plasmodium vivax malaria is underway. A model to assess the protective efficacy of vaccine candidates in humans is urgently needed. Given the lack of continuous P. vivax cultures, we developed a system to infect Anopheles albimanus mosquitoes using blood from P. vivax-infected patients and determined parameters for challenge of malaria-naive volunteers by mosquito bite. Absence of co-infections in parasitized blood was confirmed by tests consistent with blood bank screening. A total of 119 experiments were conducted using batches of 900–4,500 mosquitoes fed by an artificial membrane feeding method. Optimal conditions for mosquito probing and infection were determined. Presence of oocyst and sporozoites were assessed on Days 7–8 and 14–15, respectively, and conditions to choose batches of infected mosquitoes for sporozoite challenge were established. Procedures to infect volunteers took a 2-hour period including verification of inoculum dose. Anopheles albimanus mosquitoes represent a valuable resource for P. vivax sporozoite challenge of volunteers. PMID:21292875

  6. Genomic Analysis of Detoxification Supergene Families in the Mosquito Anopheles sinensis

    PubMed Central

    Zhou, Dan; Liu, Xianmiao; Sun, Yan; Ma, Lei; Shen, Bo; Zhu, Changliang

    2015-01-01

    Anopheles sinensis is an important malaria vector in China and other Southeast Asian countries, and the emergence of insecticide resistance in this mosquito poses a serious threat to the efficacy of malaria control programs. The recently published An. sinensis genome and transcriptome provide an opportunity to understand the molecular mechanisms of insecticide resistance. Analysis of the An. sinensis genome revealed 174 detoxification genes, including 93 cytochrome P450s (P450s), 31 glutathione-S-transferases (GSTs), and 50 choline/carboxylesterases (CCEs). The gene number was similar to that in An. gambiae, but represented a decrease of 29% and 42% compared with Aedes aegypti and Culex quinquefasciatus, respectively. The considerable contraction in gene number in Anopheles mosquitoes mainly occurred in two detoxification supergene families, P450s and CCEs. The available An. sinensis transcriptome was also re-analyzed to further identify key resistance-associated detoxification genes. Among 174 detoxification genes, 124 (71%) were detected. Several candidate genes overexpressed in a deltamethrin-resistant strain (DR-strain) were identified as belonging to the CYP4 or CYP6 family of P450s and the Delta GST class. These generated data provide a basis for identifying the resistance-associated genes of An. sinensis at the molecular level. PMID:26588704

  7. Characterization of Anopheles darlingi (Diptera: Culicidae) larval habitats in Belize, Central America

    NASA Technical Reports Server (NTRS)

    Manguin, S.; Roberts, D. R.; Andre, R. G.; Rejmankova, E.; Hakre, S.

    1996-01-01

    Surveys for larvae of Anopheles darlingi Root were conducted in April, May, and August 1994 in riverine habitats of central Belize (Cayo and Belize districts). An. darlingi was present during both the dry and wet seasons. Larvae were encountered most frequently in patches of floating debris along river margins. The floating mats were often formed by bamboo hanging over the banks and dense submersed bamboo roots. Larvae were found less frequently in lake margins, small lagoons, and ground pools with submersed roots and patches of floating leaves or vegetation. In addition to their association with floating debris, larvae of An. darlingi were associated positively with shade and submersed plants in riverine environments. Samples from river habitats showed the larvae of Anopheles albimanus Wiedemann to be strongly associated with sun-exposed sites containing green or blue-green algae. Unlike An. darlingi, An. albimanus was an ubiquitous mosquito, the immatures of which occurred in a wide variety of riverine and nonriverine aquatic habitats. Based on published reports and our experience, the association of An. darlingi with river systems was verified, and its distribution in Central America and Mexico was mapped.

  8. Population genetics of the malaria vector Anopheles aconitus in China and Southeast Asia

    PubMed Central

    Chen, Bin; Harbach, Ralph E.; Walton, Catherine; He, Zhengbo; Zhong, Daibin; Yan, Guiyun; Butlin, Roger K.

    2012-01-01

    Anopheles aconitus is a well-known vector of malaria and is broadly distributed in the Oriental Region, yet there is no information on its population genetic characteristics. In this study, the genetic differentiation among populations was examined using 140 mtDNA COII sequences from 21 sites throughout southern China, Myanmar, Vietnam, Thailand, Laos and Sri Lanka. The population in Sri Lanka has characteristic rDNA D3 and ITS2, mtDNA COII and ND5 haplotypes, and may be considered a distinct subspecies. Clear genetic structure was observed with highly significant genetic variation present among population groups in Southeast Asia. The greatest genetic diversity exists in Yunnan and Myanmar population groups. All population groups are significantly different from one another in pairwise Fst values, except northern Thailand with central Thailand. Mismatch distributions and extremely significant Fs values suggest that the populations passed through a recent demographic expansion. These patterns are discussed in relation to the likely biogeographic history of the region and compared to other Anopheles species. PMID:22982161

  9. Ecology of Anopheles darlingi Root with respect to vector importance: a review

    PubMed Central

    2011-01-01

    Anopheles darlingi is one of the most important malaria vectors in the Americas. In this era of new tools and strategies for malaria and vector control it is essential to have knowledge on the ecology and behavior of vectors in order to evaluate appropriateness and impact of control measures. This paper aims to provide information on the importance, ecology and behavior of An. darlingi. It reviews publications that addressed ecological and behavioral aspects that are important to understand the role and importance of An. darlingi in the transmission of malaria throughout its area of distribution. The results show that Anopheles darlingi is especially important for malaria transmission in the Amazon region. Although numerous studies exist, many aspects determining the vectorial capacity of An. darlingi, i.e. its relation to seasons and environmental conditions, its gonotrophic cycle and longevity, and its feeding behavior and biting preferences, are still unknown. The vector shows a high degree of variability in behavioral traits. This makes it difficult to predict the impact of ongoing changes in the environment on the mosquito populations. Recent studies indicate a good ability of An. darlingi to adapt to environments modified by human development. This allows the vector to establish populations in areas where it previously did not exist or had been controlled to date. The behavioral variability of the vector, its adaptability, and our limited knowledge of these impede the establishment of effective control strategies. Increasing our knowledge of An. darlingi is necessary. PMID:21923902

  10. An overview of malaria transmission from the perspective of Amazon Anopheles vectors

    PubMed Central

    Pimenta, Paulo FP; Orfano, Alessandra S; Bahia, Ana C; Duarte, Ana PM; Ríos-Velásquez, Claudia M; Melo, Fabrício F; Pessoa, Felipe AC; Oliveira, Giselle A; Campos, Keillen MM; Villegas, Luis Martínez; Rodrigues, Nilton Barnabé; Nacif-Pimenta, Rafael; Simões, Rejane C; Monteiro, Wuelton M; Amino, Rogerio; Traub-Cseko, Yara M; Lima, José BP; Barbosa, Maria GV; Lacerda, Marcus VG; Tadei, Wanderli P; Secundino, Nágila FC

    2015-01-01

    In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence. PMID:25742262

  11. Low and seasonal malaria transmission in the middle Senegal River basin: identification and characteristics of Anopheles vectors

    PubMed Central

    2012-01-01

    Background During the last decades two dams were constructed along the Senegal River. These intensified the practice of agriculture along the river valley basin. We conducted a study to assess malaria vector diversity, dynamics and malaria transmission in the area. Methods A cross-sectional entomological study was performed in September 2008 in 20 villages of the middle Senegal River valley to evaluate the variations of Anopheles density according to local environment. A longitudinal study was performed, from October 2008 to January 2010, in 5 selected villages, to study seasonal variations of malaria transmission. Results Among malaria vectors, 72.34% of specimens collected were An. arabiensis, 5.28% An. gambiae of the S molecular form, 3.26% M form, 12.90% An. pharoensis, 4.70% An. ziemanni, 1.48% An. funestus and 0.04% An. wellcomei. Anopheles density varied according to village location. It ranged from 0 to 21.4 Anopheles/room/day and was significantly correlated with the distance to the nearest ditch water but not to the river. Seasonal variations of Anopheles density and variety were observed with higher human biting rates during the rainy season (8.28 and 7.55 Anopheles bite/man/night in October 2008 and 2009 respectively). Transmission was low and limited to the rainy season (0.05 and 0.06 infected bite/man/night in October 2008 and 2009 respectively). During the rainy season, the endophagous rate was lower, the anthropophagic rate higher and L1014F kdr frequency higher. Conclusions Malaria vectors are present at low-moderate density in the middle Senegal River basin with An. arabiensis as the predominant species. Other potential vectors are An. gambiae M and S form and An. funestus. Nonetheless, malaria transmission was extremely low and seasonal. PMID:22269038

  12. Effect of Novaluron (Rimon 10 EC) on the mosquitoes Anopheles albimanus, Anopheles pseudopunctipennis, Aedes aegypti, Aedes albopictus and Culex quinquefasciatus from Chiapas, Mexico.

    PubMed

    Arredondo-Jiménez, J I; Valdez-Delgado, K M

    2006-12-01

    Dengue fever is a serious problem in Mexico and vector control has not been effective enough at preventing outbreaks. Malaria is largely under control, but it is important that new control measures continue to be developed. Novaluron, a novel host-specific insect growth regulator and chitin synthesis inhibitor, has proved to be effective against agricultural pests, but its efficacy against larval mosquito vectors under field conditions remains unknown. In accordance with the World Health Organization Pesticide Evaluation Scheme, phase I, II and III studies were conducted to evaluate the efficacy and residual effect of Novaluron (Rimon 10 EC, Makhteshim, Beer-Sheva, Israel) on the malaria vectors Anopheles albimanus Wiedemann (Diptera: Culicidae) and Anopheles pseudopunctipennis Theobald, the dengue vectors Aedes aegypti (L) and Aedes albopictus Skuse and the nuisance mosquito Culex quinquefasciatus Say. Laboratory susceptibility tests yielded diagnostic concentrations for all five target species. Field trials to identify the optimum field dosage of Novaluron against Anopheles mosquitoes were carried out under semi-natural conditions in artificial plots and in vessels with wild mosquitoes. Efficacy was measured by monitoring mortality of larvae and pupae and the percentage of inhibition of emergence from floating cages. Dosages of Novaluron for field tests were based on pupal LC(99) (lethal concentration 99%) of An. pseudopunctipennis (0.166 mg/L) in plots and average pupal LC(99) of Ae. aegypti and Ae. albopictus (0.55 mg/L). At all dosages tested, Novaluron significantly reduced larval populations of An. albimanus, Culex coronator Dyar & Knab, Ae. albopictus and Cx. quinquefasciatus by approximately 90%, inhibited adult emergence of An. albimanus and An. pseudopunctipennis by approximately 97% for almost 4 months in experimental plots, and inhibited adult emergence of Ae. aegypti and Ae. albopictus by approximately 97% for up to 14 weeks. Recommended dosages of

  13. Mosquito larvicidal properties of Orthisiphon thymiflorus (Roth) Sleesen. (Family: Labiatae) against mosquito vectors, Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: To determine the larvicidal activity of hexane, chloroform, ethyl acetate, acetone, and methanol extracts of Orthosiphon thymiflorus leaves against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti. Methods: Larvicidal activity was determined in laboratory bioassays using var...

  14. The relationship between wing length, blood meal volume, and fecundity for seven colonies of Anopheles species housed at the Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.

    PubMed

    Phasomkusolsil, Siriporn; Pantuwattana, Kanchana; Tawong, Jaruwan; Khongtak, Weeraphan; Kertmanee, Yossasin; Monkanna, Nantaporn; Klein, Terry A; Kim, Heung-Chul; McCardle, Patrick W

    2015-12-01

    Established colonies of Anopheles campestris, Anopheles cracens, Anopheles dirus, Anopheles kleini, Anopheles minimus, Anopheles sawadwongporni, and Anopheles sinensis are maintained at the Armed Forces Research Institute of Medical Sciences (AFRIMS). Females were provided blood meals on human blood containing citrate as an anticoagulant using an artificial membrane feeder. The mean wing length, used as an estimate of body size, for each species was compared to blood-feeding duration (time), blood meal volume, and numbers of eggs oviposited. Except for An. campestris and An. cracens, there were significant interspecies differences in wing length. The mean blood meal volumes (mm(3)) of An. kleini and An. sinensis were significantly higher than the other 5 species. For all species, the ratios of unfed females weights/blood meal volumes were similar (range: 0.76-0.88), except for An. kleini (1.08) and An. cracens (0.52), that were significantly higher and lower, respectively. Adult females were allowed to feed undisturbed for 1, 3, and 5min intervals before blood feeding was interrupted. Except for An. campestris and An. sawadwongporni, the number of eggs oviposited were significantly higher for females that fed for 3min when compared to those that only fed for 1min. This information is critical to better understand the biology of colonized Anopheles spp. and their role in the transmission of malaria parasites as they relate to the relative size of adult females, mean volumes of blood of engorged females for each of the anopheline species, and the effect of blood feeding duration on specific blood meal volumes and fecundity.

  15. Development of a Gravid Trap for Collecting Live Malaria Vectors Anopheles gambiae s.l.

    PubMed Central

    Dugassa, Sisay; Lindh, Jenny M.; Oyieke, Florence; Mukabana, Wolfgang R.; Lindsay, Steven W.; Fillinger, Ulrike

    2013-01-01

    Background Effective malaria vector control targeting indoor host-seeking mosquitoes has resulted in fewer vectors entering houses in many areas of sub-Saharan Africa, with the proportion of vectors outdoors becoming more important in the transmission of this disease. This study aimed to develop a gravid trap for the outdoor collection of the malaria vector Anopheles gambiae s.l. based on evaluation and modification of commercially available gravid traps. Methods Experiments were implemented in an 80 m2 semi-field system where 200 gravid Anopheles gambiae s.s. were released nightly. The efficacy of the Box, CDC and Frommer updraft gravid traps was compared. The Box gravid trap was tested to determine if the presence of the trap over water and the trap’s sound affected catch size. Mosquitoes approaching the treatment were evaluated using electrocuting nets or detergents added to the water in the trap. Based on the results, a new gravid trap (OviART trap) that provided an open, unobstructed oviposition site was developed and evaluated. Results Box and CDC gravid traps collected similar numbers (relative rate (RR) 0.8, 95% confidence interval (CI) 0.6–1.2; p = 0.284), whereas the Frommer trap caught 70% fewer mosquitoes (RR 0.3, 95% CI 0.2–0.5; p < 0.001). The number of mosquitoes approaching the Box trap was significantly reduced when the trap was positioned over a water-filled basin compared to an open pond (RR 0.7 95% CI 0.6–0.7; p < 0.001). This effect was not due to the sound of the trap. Catch size increased by 60% (RR 1.6, 1.2–2.2; p = 0.001) with the new OviART trap. Conclusion Gravid An. Gambiae s.s. females were visually deterred by the presence of the trapping device directly over the oviposition medium. Based on these investigations, an effective gravid trap was developed that provides open landing space for egg-laying Anopheles. PMID:23861952

  16. Blood meal origins and insecticide susceptibility of Anopheles arabiensis from Chano in South-West Ethiopia

    PubMed Central

    2013-01-01

    Background Anopheles arabiensis, the main malaria vector in Ethiopia, shows both anthropophilic and zoophilic behaviours. Insecticide resistance is increasing, and alternative methods of vector control are needed. The objectives of this study were to determine the blood meal origins and the susceptibility to insecticides of An. arabiensis from Chano village near Arba Minch in South-West Ethiopia. Methods Blood meal sources of anopheline mosquitoes collected using Centers for Disease Control and Prevention (CDC) light traps and pyrethrum spray catches (PSC) from human dwellings, and hand-held mouth aspirators from outdoor pit shelters were analysed using a direct enzyme-linked-immunosorbent assay (ELISA). The susceptibility of An. arabiensis to pyrethroid insecticides (alphacypermethrin, lambdacyhalothrin, deltamethrin, and cyfluthrin) and DDT was assessed using females reared from larval and pupal collections from natural breeding sites. Results The blood meal origins of 2967 freshly fed Anopheles mosquitoes were determined. An. arabiensis was the predominant species (75%), and it fed mainly on cattle. The densities of both freshly fed An. arabiensis and those fed on human blood followed similar seasonal patterns. The overall human blood index (HBI) of An. arabiensis, including mixed blood meals, was 44% and the bovine blood index (BBI) was 69%. The HBI of An. arabiensis from CDC light trap collections was 75% and this was higher than those for PSC (38%) and outdoor pit shelter collections (13%), while the BBI was 65% for PSC, 68% for outdoor pit shelters and 72% for CDC light traps. More freshly fed and human blood-fed An. arabiensis were sampled from houses close to the shore of Lake Abaya (the major breeding site). A high proportion of An. arabiensis was resistant to the pyrethroid insecticides, with a mortality rate of 56% for lambdacyhalothrin, 50% for cyfluthrin and alphacypermethrin, 47% for deltamethrin, and 10% for DDT. Conclusion Anopheles arabiensis is

  17. Identification of one capa and two pyrokinin receptors from the malaria mosquito Anopheles gambiae.

    PubMed

    Olsen, Stine S; Cazzamali, Giuseppe; Williamson, Michael; Grimmelikhuijzen, Cornelis J P; Hauser, Frank

    2007-10-19

    We cloned the cDNA of three evolutionarily related G protein-coupled receptors from the malaria mosquito Anopheles gambiae and functionally expressed them in Chinese hamster ovary cells. One receptor, Ang-Capa-R, was only activated by the two Anopheles capa neuropeptides Ang-capa-1 (GPTVGLFAFPRVamide) and Ang-capa-2 (pQGLVPFPRVamide) with EC(50) values of 8.6x10(-9)M and 3.3x10(-9)M, respectively, but not by any other known mosquito neuropeptide. The second receptor, Ang-PK-1-R, was selectively activated by the Anopheles pyrokinin-1 peptides Ang-PK-1-1 (AGGTGANSAMWFGPRLamide) and Ang-PK-1-2 (AAAMWFGPRLamide) with EC(50) values of 3.3x10(-8)M and 2.5x10(-8)M, respectively, but not by mosquito capa or pyrokinin-2 peptides. For the third receptor, Ang-PK-2-R, the most potent ligands were the pyrokinin-2 peptides Ang-PK-2-1 (DSVGENHQRPPFAPRLamide) and Ang-PK-2-2 (NLPFSPRLamide) with EC(50) values of 5.2x10(-9)M and 6.4x10(-9)M, respectively. However, this receptor could also be activated by the two pyrokinins-1, albeit with lower potency (EC(50): 2-5x10(-8)M). Because Ang-capa-1 and -2 and Ang-PK-1-1 are located on one preprohormone and the other peptides on another prohormone, these results imply a considerable crosstalk between the capa, pyrokinin-1 and pyrokinin-2 systems. Gene structure and phylogenetic tree analyses showed that Ang-Capa-R was the orthologue of the Drosophila capa receptor CG14575, Ang-PK-1-R the orthologue of the Drosophila pyrokinin-1 receptor CG9918, and Ang-PK-2-R the orthologue of the Drosophila pyrokinin-2 receptors CG8784 and CG8795. This is the first report on the functional characterization and crosstalk properties of capa and pyrokinin receptors in mosquitoes.

  18. Predicting the potential distribution of main malaria vectors Anopheles stephensi, An. culicifacies s.l. and An. fluviatilis s.l. in Iran based on maximum entropy model.

    PubMed

    Pakdad, Kamran; Hanafi-Bojd, Ahmad Ali; Vatandoost, Hassan; Sedaghat, Mohammad Mehdi; Raeisi, Ahmad; Moghaddam, Abdolreza Salahi; Foroushani, Abbas Rahimi

    2017-05-01

    Malaria is considered as a major public health problem in southern areas of Iran. The goal of this study was to predict best ecological niches of three main malaria vectors of Iran: Anopheles stephensi, Anopheles culicifacies s.l. and Anopheles fluviatilis s.l. A databank was created which included all published data about Anopheles species of Iran from 1961 to 2015. The suitable environmental niches for the three above mentioned Anopheles species were predicted using maximum entropy model (MaxEnt). AUC (area under Roc curve) values were 0.943, 0.974 and 0.956 for An. stephensi, An. culicifacies s.l. and An. fluviatilis s.l respectively, which are considered as high potential power of model in the prediction of species niches. The biggest bioclimatic contributor for An. stephensi and An. fluviatilis s.l. was bio 15 (precipitation seasonality), 25.5% and 36.1% respectively, followed by bio 1 (annual mean temperature), 20.8% for An. stephensi and bio 4 (temperature seasonality) with 49.4% contribution for An. culicifacies s.l. This is the first step in the mapping of the country's malaria vectors. Hence, future weather situation can change the dispersal maps of Anopheles. Iran is under elimination phase of malaria, so that such spatio-temporal studies are essential and could provide guideline for decision makers for IVM strategies in problematic areas.

  19. Effects of transmission-blocking immunity on Plasmodium vivax infections in Anopheles albimanus populations.

    PubMed

    Ramsey, J M; Salinas, E; Rodriguez, M H; Beaudoin, R L

    1994-02-01

    Two colonized populations of Anopheles albimanus isolated from the Suchiate region, Chiapas State, Mexico, were compared for their susceptibility to coindigenous Plasmodium vivax. Groups of mosquitoes were fed in vitro with either autologous donor blood or the same blood cells substituted with serum negative for anti-gametocyte antibody. Significant differences in susceptibility between the 2 colonies were encountered if the autologous blood from a patient was fed to mosquitoes: mean infection rates of AnA2-positive groups was double that in AnA1 mosquitoes. Consistent for both colonies, only 23.6% of samples positive from malaria-negative serum-substituted blood were infected with an autologous blood feed. Vector competence in these mosquito populations was partially linked to the human populations's immune response to the parasite.

  20. Molecular Taxonomy Provides New Insights into Anopheles Species of the Neotropical Arribalzagia Series

    PubMed Central

    Gómez, Giovan F.; Bickersmith, Sara A.; González, Ranulfo; Conn, Jan E.; Correa, Margarita M.

    2015-01-01

    Phylogenetic analysis of partial mitochondrial cytochrome oxidase c subunit I (COI) and nuclear internal transcribed spacer 2 (ITS2) sequences were used to evaluate initial identification and to investigate phylogenetic relationships of seven Anopheles morphospecies of the Arribalzagia Series from Colombia. Phylogenetic trees recovered highly supported clades for An. punctimaculas.s., An. calderoni, An. malefactor s.l., An. neomaculipalpus, An. apicimacula s.l., An. mattogrossensis and An. peryassui. This study provides the first molecular confirmation of An. malefactorfrom Colombia and discovered conflicting patterns of divergence for the molecular markers among specimens from northeast and northern Colombia suggesting the presence of two previously unrecognized Molecular Operational Taxonomic Units (MOTUs). Furthermore, two highly differentiated An. apicimacula MOTUs previously found in Panama were detected. Overall, the combined molecular dataset facilitated the detection of known and new Colombian evolutionary lineages, and constitutes the baseline for future research on their bionomics, ecology and potential role as malaria vectors. PMID:25774795

  1. Use of generalized regression tree models to characterize vegetation favoring Anopheles albimanus breeding.

    PubMed

    Hernandez, J E; Epstein, L D; Rodriguez, M H; Rodriguez, A D; Rejmankova, E; Roberts, D R

    1997-03-01

    We propose the use of generalized tree models (GTMs) to analyze data from entomological field studies. Generalized tree models can be used to characterize environments with different mosquito breeding capacity. A GTM simultaneously analyzes a set of predictor variables (e.g., vegetation coverage) in relation to a response variable (e.g., counts of Anopheles albimanus larvae), and how it varies with respect to a set of criterion variables (e.g., presence of predators). The algorithm produces a treelike graphical display with its root at the top and 2 branches stemming down from each node. At each node, conditions on the value of predictors partition the observations into subgroups (environments) in which the relation between response and criterion variables is most homogeneous.

  2. Biological variation in two Anopheles vestitipennis populations with different feeding preferences in southern Mexico.

    PubMed

    Ulloa, Armando; Rodríguez, Mario H; Arredondo-Jimenez, Juan I; Fernandez-Salas, Ildefonso

    2005-12-01

    The lengths of gonotrophic cycle and egg development and survival rate were studied in Anopheles vestitipennis collected in horse and human-baited traps in southern Mexico. The gonotrophic cycle duration was estimated using cross-correlation analysis, whereas the survival rate was assessed using a vertical method. Daily changes of parity rates gave significant correlation indices at 3 and 4 days in the zoophilic and anthropophilic populations, respectively. The minimum time required to develop mature eggs after blood feeding was 54 and 60 h, and the survival rate was 0.93 and 0.88 in zoophilic and anthropophilic female mosquito populations, respectively. These biological differences provide additional support for the existence of subpopulations with distinctive feeding preferences within An. vestitipennis in southern Mexico.

  3. Intradomiciliary behavior of Anopheles albimanus on the coastal plain of southern Mexico: implications for malaria control.

    PubMed

    Bown, D N; Rodriguez, M H; Arredondo-Jimenez, J I; Loyola, E G; Rodriguez, M C

    1993-09-01

    The postfeeding indoor resting behavior of Anopheles albimanus in experimental houses in southern México was investigated by using a mark-recapture procedure. The majority of mosquitoes rested inside houses after taking a blood meal indoors. There was a higher landing frequency on interior surfaces other than walls and roofs; however, mosquitoes rested for longer periods on these 2 surfaces. Successive landings on walls after short flights showed that mosquitoes gradually increased their mean landing height from 1.0 to 1.4 m. Similarly, mosquitoes resting at the base of inner roofs had a successive landing height range of about 0.5 m. Based on these observations and the potential for reduction of nearly 50% in the quantity of insecticide used and the time needed to apply it, village-scale studies involving the selective spraying of a 1-m-wide swath of insecticide on walls and on roofs are recommended in this area.

  4. Behavioral response of Anopheles darlingi to DDT-sprayed house walls in Amazonia.

    PubMed

    Roberts, D R; Alecrim, W D

    1991-01-01

    The behavioral response of Anopheles darlingi females to spraying of house walls with DDT was studied along the Ituxi River in Amazonas, Brazil, using a house sprayed with 2 g DDT per square meter of wall surface and an untreated house serving as a control. It was found that hardly any An. darlingi females entered, exited, or took blood meals inside the treated house after it was sprayed with DDT, and that specimens marked and released inside the house tended to depart immediately. This behavior appears to constitute true repellency rather than contact irritability. Since the typical house in the vicinity of the study site had only two walls, the persistence of malaria in the local area was probably due to home construction practices.

  5. Microplate assay analysis of the distribution of organophosphate and carbamate resistance in Guatemalan Anopheles albimanus

    PubMed Central

    Brogdon, W. G.; Beach, R. F.; Stewart, J. M.; Castanaza, L.

    1988-01-01

    Simple microplate assay methods for determining the frequency of insecticide resistance in single mosquitos were used to study the distribution and localization of organophosphate and carbamate resistance in field populations of Anopheles albimanus Weidemann in Guatemala, where such resistance, caused by heavy use of agricultural pesticides, has long been assumed to be widespread. Areas of complete susceptibility to organophosphates and carbamates were observed, as well as areas where the resistant phenotypes represented up to 98% of the population. Overall, the resistance levels were lower and more localized than expected. Two mechanisms of resistance were identified by the microassay methods. These were the elevated esterase (nonspecific esterase) and insensitive acetylcholinesterase mechanisms which were selected independently, the former (documented for the first time in Central American anophelines) being predominant. These methods represent a promising new technology for the detection and assessment of resistance and will facilitate improved control strategy decisions. PMID:3262440

  6. Assessment of the residual toxicity to Anopheles gambiae of the organophosphorus insecticides malathion and Baytex

    PubMed Central

    Smith, A.; Hocking, K. S.

    1962-01-01

    As part of a WHO programme to evaluate possible substitutes for the chlorinated hydrocarbons to which anopheline mosquitos in many countries have become resistant, two organophosphorus insecticides, malathion and Baytex, were tested as residual sprays on various types of surface against Anopheles gambiae adults in experimental huts at Magugu in Tanganyika. The long-lasting toxicity of both insecticides on relatively impervious surfaces was confirmed, but—as is the case with the chlorinated hydrocarbons—shorter persistence was obtained on sorptive surfaces. As most of the mosquitos rested on the roof, its surface was of much greater importance than the wall surface in determining kill; trials with naturally entering mosquitos indicated that where the roof was of grass malathion was to be preferred to Baytex. Observations confirmed that control huts attracted far more mosquitos than the treated huts and that the insecticide vapour apparently masked the human odour. PMID:13993107

  7. High-Resolution Cytogenetic Map for the African Malaria Vector Anopheles gambiae

    PubMed Central

    George, Phillip; Sharakhova, Maria V.; Sharakhov, Igor V.

    2010-01-01

    Cytogenetic and physical maps are indispensible for precise assembly of genome sequences, functional characterization of chromosomal regions, and population genetic and taxonomic studies. We have created a new cytogenetic map for Anopheles gambiae by using a high-pressure squash technique that increases overall band clarity. To link chromosomal regions to the genome sequence, we attached genome coordinates, based on 302 markers of BAC, cDNA clones, and PCR-amplified gene fragments, to the chromosomal bands and interbands at approximately a 0.5-1 Mb interval. In addition, we placed the breakpoints of seven common polymorphic inversions on the map and described the chromosomal landmarks for the arm and inversion identification. The map's improved resolution can be used to further enhance physical mapping, improve genome assembly, and stimulate epigenomic studies of malaria vectors. PMID:20609021

  8. In vitro and in vivo host range of Anopheles gambiae densovirus (AgDNV).

    PubMed

    Suzuki, Yasutsugu; Barik, Tapan K; Johnson, Rebecca M; Rasgon, Jason L

    2015-07-29

    AgDNV is a powerful gene transduction tool and potential biological control agent for Anopheles mosquitoes. Using a GFP reporter virus system, we investigated AgDNV host range specificity in four arthropod cell lines (derived from An. gambiae, Aedes albopictus and Drosophila melanogaster) and six mosquito species from 3 genera (An. gambiae, An. arabiensis, An. stephensi, Ae. albopictus, Ae. aegypti and Culex tarsalis). In vitro, efficient viral invasion, replication and GFP expression was only observed in MOS55 An. gambiae cells. In vivo, high levels of GFP were observed in An. gambiae mosquitoes. Intermediate levels of GFP were observed in the closely related species An. arabiensis. Low levels of GFP were observed in An. stephensi, Ae. albopictus, Ae. aegypti and Cx. tarsalis. These results suggest that AgDNV is a specific gene transduction tool for members of the An. gambiae species complex, and could be potentially developed into a biocontrol agent with minimal off-target effects.

  9. “Highly evolvable malaria vectors: the genomes of 16 Anopheles mosquitoes”

    PubMed Central

    Neafsey, Daniel E.; Waterhouse, Robert M.; Abai, Mohammad R.; Aganezov, Sergey S.; Alekseyev, Max A.; Allen, James E.; Amon, James; Arcà, Bruno; Arensburger, Peter; Artemov, Gleb; Assour, Lauren A.; Basseri, Hamidreza; Berlin, Aaron; Birren, Bruce W.; Blandin, Stephanie A.; Brockman, Andrew I.; Burkot, Thomas R.; Burt, Austin; Chan, Clara S.; Chauve, Cedric; Chiu, Joanna C.; Christensen, Mikkel; Costantini, Carlo; Davidson, Victoria L.M.; Deligianni, Elena; Dottorini, Tania; Dritsou, Vicky; Gabriel, Stacey B.; Guelbeogo, Wamdaogo M.; Hall, Andrew B.; Han, Mira V.; Hlaing, Thaung; Hughes, Daniel S.T.; Jenkins, Adam M.; Jiang, Xiaofang; Jungreis, Irwin; Kakani, Evdoxia G.; Kamali, Maryam; Kemppainen, Petri; Kennedy, Ryan C.; Kirmitzoglou, Ioannis K.; Koekemoer, Lizette L.; Laban, Njoroge; Langridge, Nicholas; Lawniczak, Mara K.N.; Lirakis, Manolis; Lobo, Neil F.; Lowy, Ernesto; MacCallum, Robert M.; Mao, Chunhong; Maslen, Gareth; Mbogo, Charles; McCarthy, Jenny; Michel, Kristin; Mitchell, Sara N.; Moore, Wendy; Murphy, Katherine A.; Naumenko, Anastasia N.; Nolan, Tony; Novoa, Eva M.; O'Loughlin, Samantha; Oringanje, Chioma; Oshaghi, Mohammad A.; Pakpour, Nazzy; Papathanos, Philippos A.; Peery, Ashley N.; Povelones, Michael; Prakash, Anil; Price, David P.; Rajaraman, Ashok; Reimer, Lisa J.; Rinker, David C.; Rokas, Antonis; Russell, Tanya L.; Sagnon, N'Fale; Sharakhova, Maria V.; Shea, Terrance; Simão, Felipe A.; Simard, Frederic; Slotman, Michel A.; Somboon, Pradya; Stegniy, Vladimir; Struchiner, Claudio J.; Thomas, Gregg W.C.; Tojo, Marta; Topalis, Pantelis; Tubio, José M.C.; Unger, Maria F.; Vontas, John; Walton, Catherine; Wilding, Craig S.; Willis, Judith H.; Wu, Yi-Chieh; Yan, Guiyun; Zdobnov, Evgeny M.; Zhou, Xiaofan; Catteruccia, Flaminia; Christophides, George K.; Collins, Frank H.; Cornman, Robert S.; Crisanti, Andrea; Donnelly, Martin J.; Emrich, Scott J.; Fontaine, Michael C.; Gelbart, William; Hahn, Matthew W.; Hansen, Immo A.; Howell, Paul I.; Kafatos, Fotis C.; Kellis, Manolis; Lawson, Daniel; Louis, Christos; Luckhart, Shirley; Muskavitch, Marc A.T.; Ribeiro, José M.; Riehle, Michael A.; Sharakhov, Igor V.; Tu, Zhijian; Zwiebel, Laurence J.; Besansky, Nora J.

    2015-01-01

    Variation in vectorial capacity for human malaria among Anopheles mosquito species is determined by many factors, including behavior, immunity, and life history. To investigate the genomic basis of vectorial capacity and explore new avenues for vector control, we sequenced the genomes of 16 anopheline mosquito species from diverse locations spanning ~100 million years of evolution. Comparative analyses show faster rates of gene gain and loss, elevated gene shuffling on the X chromosome, and more intron losses, relative to Drosophila. Some determinants of vectorial capacity, such as chemosensory genes, do not show elevated turnover, but instead diversify through protein-sequence changes. This dynamism of anopheline genes and genomes may contribute to their flexible capacity to take advantage of new ecological niches, including adapting to humans as primary hosts. PMID:25554792

  10. Adaptive introgression between Anopheles sibling species eliminates a major genomic island but not reproductive isolation

    PubMed Central

    Clarkson, Chris S.; Weetman, David; Essandoh, John; Yawson, Alexander E.; Maslen, Gareth; Manske, Magnus; Field, Stuart G.; Webster, Mark; Antão, Tiago; MacInnis, Bronwyn; Kwiatkowski, Dominic; Donnelly, Martin J.

    2014-01-01

    Adaptive introgression can provide novel genetic variation to fuel rapid evolutionary responses, though it may be counterbalanced by potential for detrimental disruption of the recipient genomic background. We examine the extent and impact of recent introgression of a strongly selected insecticide-resistance mutation (Vgsc-1014F) located within one of two exceptionally large genomic islands of divergence separating the Anopheles gambiae species pair. Here we show that transfer of the Vgsc mutation results in homogenization of the entire genomic island region (~1.5% of the genome) between species. Despite this massive disruption, introgression is clearly adaptive with a dramatic rise in frequency of Vgsc-1014F and no discernable impact on subsequent reproductive isolation between species. Our results show (1) how resilience of genomes to massive introgression can permit rapid adaptive response to anthropogenic selection and (2) that even extreme prominence of genomic islands of divergence can be an unreliable indicator of importance in speciation. PMID:24963649

  11. Adaptive introgression between Anopheles sibling species eliminates a major genomic island but not reproductive isolation.

    PubMed

    Clarkson, Chris S; Weetman, David; Essandoh, John; Yawson, Alexander E; Maslen, Gareth; Manske, Magnus; Field, Stuart G; Webster, Mark; Antão, Tiago; MacInnis, Bronwyn; Kwiatkowski, Dominic; Donnelly, Martin J

    2014-06-25

    Adaptive introgression can provide novel genetic variation to fuel rapid evolutionary responses, though it may be counterbalanced by potential for detrimental disruption of the recipient genomic background. We examine the extent and impact of recent introgression of a strongly selected insecticide-resistance mutation (Vgsc-1014F) located within one of two exceptionally large genomic islands of divergence separating the Anopheles gambiae species pair. Here we show that transfer of the Vgsc mutation results in homogenization of the entire genomic island region (~1.5% of the genome) between species. Despite this massive disruption, introgression is clearly adaptive with a dramatic rise in frequency of Vgsc-1014F and no discernable impact on subsequent reproductive isolation between species. Our results show (1) how resilience of genomes to massive introgression can permit rapid adaptive response to anthropogenic selection and (2) that even extreme prominence of genomic islands of divergence can be an unreliable indicator of importance in speciation.

  12. Repellency effect of forty-one essential oils against Aedes, Anopheles, and Culex mosquitoes.

    PubMed

    Amer, Abdelkrim; Mehlhorn, Heinz

    2006-09-01

    Since ancient times, plant products were used in various aspects. However, their use against pests decreased when chemical products became developed. Recently, concerns increased with respect to public health and environmental security requiring detection of natural products that may be used against insect pests. In this study, 41 plant extracts and 11 oil mixtures were evaluated against the yellow fever mosquito, Aedes aegypti (Linnaeus), the malaria vector, Anopheles stephensi (Liston), and the filariasis and encephalitis vector, Culex quinquefasciatus (Say) (Diptera: Culicidae) using the skin of human volunteers to find out the protection time and repellency. The five most effective oils were those of Litsea (Litsea cubeba), Cajeput (Melaleuca leucadendron), Niaouli (Melaleuca quinquenervia), Violet (Viola odorata), and Catnip (Nepeta cataria), which induced a protection time of 8 h at the maximum and a 100% repellency against all three species. This effect needs, however, a peculiar formulation to fix them on the human skin.

  13. Mosquito genomics. Highly evolvable malaria vectors: the genomes of 16 Anopheles mosquitoes.

    PubMed

    Neafsey, Daniel E; Waterhouse, Robert M; Abai, Mohammad R; Aganezov, Sergey S; Alekseyev, Max A; Allen, James E; Amon, James; Arcà, Bruno; Arensburger, Peter; Artemov, Gleb; Assour, Lauren A; Basseri, Hamidreza; Berlin, Aaron; Birren, Bruce W; Blandin, Stephanie A; Brockman, Andrew I; Burkot, Thomas R; Burt, Austin; Chan, Clara S; Chauve, Cedric; Chiu, Joanna C; Christensen, Mikkel; Costantini, Carlo; Davidson, Victoria L M; Deligianni, Elena; Dottorini, Tania; Dritsou, Vicky; Gabriel, Stacey B; Guelbeogo, Wamdaogo M; Hall, Andrew B; Han, Mira V; Hlaing, Thaung; Hughes, Daniel S T; Jenkins, Adam M; Jiang, Xiaofang; Jungreis, Irwin; Kakani, Evdoxia G; Kamali, Maryam; Kemppainen, Petri; Kennedy, Ryan C; Kirmitzoglou, Ioannis K; Koekemoer, Lizette L; Laban, Njoroge; Langridge, Nicholas; Lawniczak, Mara K N; Lirakis, Manolis; Lobo, Neil F; Lowy, Ernesto; MacCallum, Robert M; Mao, Chunhong; Maslen, Gareth; Mbogo, Charles; McCarthy, Jenny; Michel, Kristin; Mitchell, Sara N; Moore, Wendy; Murphy, Katherine A; Naumenko, Anastasia N; Nolan, Tony; Novoa, Eva M; O'Loughlin, Samantha; Oringanje, Chioma; Oshaghi, Mohammad A; Pakpour, Nazzy; Papathanos, Philippos A; Peery, Ashley N; Povelones, Michael; Prakash, Anil; Price, David P; Rajaraman, Ashok; Reimer, Lisa J; Rinker, David C; Rokas, Antonis; Russell, Tanya L; Sagnon, N'Fale; Sharakhova, Maria V; Shea, Terrance; Simão, Felipe A; Simard, Frederic; Slotman, Michel A; Somboon, Pradya; Stegniy, Vladimir; Struchiner, Claudio J; Thomas, Gregg W C; Tojo, Marta; Topalis, Pantelis; Tubio, José M C; Unger, Maria F; Vontas, John; Walton, Catherine; Wilding, Craig S; Willis, Judith H; Wu, Yi-Chieh; Yan, Guiyun; Zdobnov, Evgeny M; Zhou, Xiaofan; Catteruccia, Flaminia; Christophides, George K; Collins, Frank H; Cornman, Robert S; Crisanti, Andrea; Donnelly, Martin J; Emrich, Scott J; Fontaine, Michael C; Gelbart, William; Hahn, Matthew W; Hansen, Immo A; Howell, Paul I; Kafatos, Fotis C; Kellis, Manolis; Lawson, Daniel; Louis, Christos; Luckhart, Shirley; Muskavitch, Marc A T; Ribeiro, José M; Riehle, Michael A; Sharakhov, Igor V; Tu, Zhijian; Zwiebel, Laurence J; Besansky, Nora J

    2015-01-02

    Variation in vectorial capacity for human malaria among Anopheles mosquito species is determined by many factors, including behavior, immunity, and life history. To investigate the genomic basis of vectorial capacity and explore new avenues for vector control, we sequenced the genomes of 16 anopheline mosquito species from diverse locations spanning ~100 million years of evolution. Comparative analyses show faster rates of gene gain and loss, elevated gene shuffling on the X chromosome, and more intron losses, relative to Drosophila. Some determinants of vectorial capacity, such as chemosensory genes, do not show elevated turnover but instead diversify through protein-sequence changes. This dynamism of anopheline genes and genomes may contribute to their flexible capacity to take advantage of new ecological niches, including adapting to humans as primary hosts.

  14. Prey-predator relationship between the cyclopoids Mesocyclops longisetus and Mesocyclops meridianus with Anopheles aquasalis larvae.

    PubMed

    Pernía, Javier; de Zoppi, Roa Evelyn; Palacios-Cáceres, Mario

    2007-06-01

    Copepods from the genus Mesocyclops are considered predators and potential biological control for mosquito larvae. Two copepod species M. meridianus and M. longisetus were found in natural developmental habitat for malaria vector Anopheles aquasalis in Paria, Venezuela. Predatory potential on 1st-stage mosquito larvae An. aquasalis was evaluated under laboratory conditions for the 2 species of copepod. Further records of both copepod life cycle and body size were taken. A 2 x 3 factorial design was used, consisting of 1:1 and 10:1 prey-predator ratios with and without interspecific interactions. Despite significant body-size differences, M. longisetus and M. meridianus reached maturity 17 days after hatching with no significant differences. Life cycle span of both copepod species are described for the first time. The 2 species showed the same predatory potential despite larval (prey) abundance variation.

  15. Larvicidal activity of a few plant extracts against Culex quinquefasciatus and Anopheles stephensi.

    PubMed

    Pushpalatha, E; Muthukrishnan, J

    1995-03-01

    Larvicidal activity of partially purified extracts of leaves of Vitex negundo, Nerium oleander and seeds of Syzygium jambolanum on different instars of Culex quinquefasciatus and Anopheles stephensi was estimated. Petroleum ether (PE): Ethyl acetate (EA) 3:1 fraction of V. negundo, 1:1 fractions of N. oleander and S. jambolanum inflicted considerable larval mortality and interfered with pupal-adult metamorphosis. At very low concentration the active fractions of these plant extracts extended the duration of the various larval instars and of pupation. In general, I and II instar larvae were more susceptible to the active fractions. Species and stage specific differences in the susceptibility of the mosquitoes to the active fractions of the plant extracts were observed.

  16. Population genetic structure of malaria vector Anopheles stephensi Liston (Diptera: Culicidae).

    PubMed

    Gakhar, S K; Sharma, Richa; Sharma, Arvind

    2013-04-01

    Malaria is a complex disease that afflicts human today. Malaria epidemiology is associated with drug resistance in parasite and differential distribution and insecticide resistance in vector. Efforts are being made to eradicate malaria but burden of malaria is still increasing. Vector control is essential for malaria prevention strategies. Knowledge of population genetic structure is pre-requisite for determining prevention strategies particularly using transgenic mosquitoes. Population genetic study can predict level of gene flow between different populations. Anopheles stephensi Liston is urban vector of malaria in Indo-Pakistan subcontinent. About 12% of malaria cases of malaria in India are contributed by A. stephensi. Studies conducted on population genetics of A. stephensi using various markers in different parts of the world are discussed in this communication.

  17. Measurement of flight tone differentiates among members of the Anopheles gambiae species complex (Diptera: Culicidae).

    PubMed

    Brogdon, W G

    1998-09-01

    Through digital sampling and resampling at 5,000 and 20,000 Hz of amplified mosquito flight sound, baseline separation was observed for flight tone frequency distributions of male and female Anopheles gambiae Giles, An. arabiensis Patton, An. merus Donitz, and An. melas Theobald. Males of the 4 species showed flight tones considerably higher than females. Up to 7 harmonics were measured for each species. Close correspondence for each individual mosquito of the means of the flight tone harmonics (corrected for harmonic number) demonstrated the accuracy and precision of the method. These data indicate that flight tone differences have been subjected to selection and may act as an isolating mechanism for mating or serve some other behavioral purpose in these mosquitoes. Individuals and swarms of sympatric species were distinguished from each other for both males and females, but the allopatric species, An. merus and An. melas, were indistinguishable.

  18. Imidacloprid and Thiamethoxam Induced Mutations in Internal Transcribed Spacer 2 (ITS2) of Anopheles stephensi.

    PubMed

    Bhinder, Preety; Chaudhry, Asha; Barna, Bhupinder; Kaur, Satvinderjeet

    2012-05-01

    The present article deals with the polymerase chain reaction (PCR)-based genotoxicity evaluation of neonicotinoid pesticides, imidacloprid and thiamethoxam, by using the genome of a mosquito Anopheles stephensi taken as an experimental model. After treatment of the second instar larvae with LC(20) of the pesticides for 24 h, the induced nucleotide sequence variations in the internal transcribed spacer 2 (ITS2) of freshly hatched unfed control and treated individuals was studied from the sequence alignment data and the mutations in the form of insertion, deletion and substitution of bases were recorded. Measurable differences, indicative of the genetic damage due to imidacloprid and thiamethoxam were observed when ITS2 sequences of control and treated individuals were compared. It was found that imidacloprid-treated individual had 8 deletions, 29 insertions, 18 transitions and 33 transversions, whereas thiamethoxam-treated individual had 10 deletions, 8 insertions, 47 transitions and 68 transversions.

  19. Intraspecific nucleotide variation in Anopheles gambiae: new insights into the biology of malaria vectors.

    PubMed

    Morlais, Isabelle; Ponçon, Nicolas; Simard, Frédéric; Cohuet, Anna; Fontenille, Didier

    2004-12-01

    The Anopheles gambiae genome sequence, together with the recent development of molecular tools for genome-wide analysis, promises new insights into the biology of the malaria vector. These insights should help define the best possible breakdown point for interrupting transmission in the mosquito vector. A survey of the intraspecific nucleotide diversity in coding regions of three different mosquito strains showed an average of one single nucleotide polymorphism (SNP) every 125 coding base pairs. High levels of nucleotide polymorphism were observed in mosquito immune-related genes and pathogen recognition receptors harbored higher replacement substitutions. Genotyping at SNP loci in natural populations of An. gambiae from three malaria foci showed contrasting patterns. The distribution of mutation Y443H in the thioester-containing protein 3 (TEP3) gene suggested this mutational event has occurred under selective constraints. Our results show that SNP-based studies will be valuable in identifying the sequence variation associated with phenotypic traits shaping vector competence.

  20. Population structure of the malaria vector Anopheles funestus in Senegal based on microsatellite and cytogenetic data.

    PubMed

    Cohuet, A; Dia, I; Simard, F; Raymond, M; Fontenille, D

    2004-06-01

    The study of chromosomal inversions distribution within natural Anopheles funestus populations from West Africa revealed high levels of genetic structuring. In Burkina Faso, this was interpreted as evidence for incipient speciation, and two chromosomal forms were described, namely 'Folonzo' and 'Kiribina'. Assignation of field collected specimens to one chromosomal form depends upon application of an algorithm based on chromosomal inversions. We assessed relevance and applicability of this algorithm on An. funestus populations from Senegal, where both forms occur. Furthermore, we estimated the level of genetic differentiation between populations using microsatellite loci spread over the whole genome. Significant genetic differentiation was revealed between geographical populations of An. funestus, and the pattern observed suggested isolation by distance. Chromosomal heterogeneity was not detected by microsatellite markers. Thus, although incipient speciation could not be ruled out by our data, our results suggest that differential environmental selection pressure acting on inversions should be considered a major factor in shaping their distribution in wild An. funestus populations.

  1. Population genetic structure of the malaria vector Anopheles moucheti in south Cameroon forest region.

    PubMed

    Antonio-Nkondjio, Christophe; Ndo, Cyrille; Awono-Ambene, Parfait; Ngassam, Pierre; Fontenille, Didier; Simard, Frédéric

    2007-01-01

    We used recently developed microsatellite DNA markers to explore the population genetic structure of the malaria vector, Anopheles moucheti. Polymorphism at 10 loci was examined to assess level of genetic differentiation between four A. moucheti populations from South Cameroon situated 65-400 km apart. All microsatellite loci were highly polymorphic with a number of distinct alleles per locus ranging from 9 to 17. Fst estimates ranging from 0.0094 to 0.0275 (P < 0.001) were recorded. These results suggest a very low level of genetic differentiation between A. moucheti populations. The recently available microsatellite loci revealed useful markers to assess genetic differentiation between geographical populations of A. moucheti in Cameroon.

  2. Population genetic structure of urban malaria vector Anopheles stephensi in India.

    PubMed

    Sharma, Richa; Sharma, Arvind; Kumar, Ashwani; Dube, Madhulika; Gakhar, S K

    2016-04-01

    Malaria is a major public health problem in India because climatic condition and geography of India provide an ideal environment for development of malaria vector. Anopheles stephensi is a major urban malaria vector in India and its control has been hampered by insecticide resistance. In present study population genetic structure of A. stephensi is analyzed at macro geographic level using 13 microsatellite markers. Significantly high genetic differentiation was found in all studied populations with differentiation values (FST) ranging from 0.0398 to 0.1808. The geographic distance was found to be playing a major role in genetic differentiation between different populations. Overall three genetic pools were observed and population of central India was found to be coexisting in two genetic pools. High effective population size (Ne) was found in all the studied populations.

  3. Limited Diversity of Anopheles Darlingi in The Peruvian Amazon Region of Iquitos

    PubMed Central

    PINEDO-CANCINO, VIVIANA; SHEEN, PATRICIA; TARAZONA-SANTOS, EDUARDO; OSWALD, WILLIAM E.; JERI, CESAR; VITTOR, AMY YOMIKO; PATZ, JONATHAN A.; GILMAN, ROBERT H.

    2006-01-01

    Anopheles darlingi is the most important malaria vector in the Amazon basin of South America, and is capable of transmitting both Plasmodium falciparum and P. vivax. To understand the genetic structure of this vector in the Amazonian region of Peru, a simple polymerase chain reaction (PCR)-based test to identify this species of mosquito was used. A random amplified polymorphic DNA-PCR was used to study genetic variation at the micro-geographic level in nine geographically separate populations of An. darlingi collected in areas with different degrees of deforestation surrounding the city of Iquitos. Within-population genetic diversity in nine populations, as quantified by the expected heterozygosity (HE), ranged from 0.27 to 0.32. Average genetic distance (FST) among these populations was 0.017. These results show that the nine studied populations are highly homogeneous, suggesting that strategies can be developed to combat this malaria vector as a single epidemiologic unit. PMID:16896125

  4. Effect of bioactive fractions of Citrullus vulgaris Schrad. leaf extract against Anopheles stephensi and Aedes aegypti.

    PubMed

    Mullai, K; Jebanesan, A; Pushpanathan, T

    2008-04-01

    The benzene extract of Citrullus vulgaris was tested against Anopheles stephensi and Aedes aegypti for the larvicidal activity and ovicidal properties. The crude benzene extract was found to be more effective against A. stephensi than A. aegypti. The LC50 values were 18.56 and 42.76 ppm respectively. The LC50 values for silica gel fractions (bioactive fractions I, II, III and IV) were 11.32, 14.12, 14.53 and 16.02 ppm respectively. The mean per cent hatchability of the egg rafts were observed after 48 h post treatment. The crude extract of benzene exerted 100% mortality at 250 ppm against A. stephensi and at 300 ppm against A. aegypti. The silica gel fractions I and II afforded 100% mortality at 100 ppm and III and IV exerted the hatchability rate of 4.9 and 5.3% at the same concentration against A. stephensi.

  5. Genome expression analysis of Anopheles gambiae: responses to injury, bacterial challenge, and malaria infection.

    PubMed

    Dimopoulos, George; Christophides, George K; Meister, Stephan; Schultz, Jörg; White, Kevin P; Barillas-Mury, Carolina; Kafatos, Fotis C

    2002-06-25

    The complex gene expression responses of Anopheles gambiae to microbial and malaria challenges, injury, and oxidative stress (in the mosquito and/or a cultured cell line) were surveyed by using cDNA microarrays constructed from an EST-clone collection. The expression profiles were broadly subdivided into induced and down-regulated gene clusters. Gram+ and Gram- bacteria and microbial elicitors up-regulated a diverse set of genes, many belonging to the immunity class, and the response to malaria partially overlapped with this response. Oxidative stress activated a distinctive set of genes, mainly implicated in oxidoreductive processes. Injury up- and down-regulated gene clusters also were distinctive, prominently implicating glycolysis-related genes and citric acid cycle/oxidative phosphorylation/redox-mitochondrial functions, respectively. Cross-comparison of in vivo and in vitro responses indicated the existence of tightly coregulated gene groups that may correspond to gene pathways.

  6. A newly recognized species in the Anopheles (Nyssorhynchus) albitarsis complex (Diptera: Culicidae) from Puerto Carreno, Colombia.

    PubMed

    Brochero, Helena H L; Li, Cong; Wilkerson, Richard C

    2007-06-01

    We report a previously unrecognized mosquito species from eastern Colombia belonging to the Anopheles (Nyssorhynchus) albitarsis complex. We provisionally name this taxon An. albitarsis species "F." Until now, the only members of the Albitarsis Complex recorded from north of the Amazon River have been An. marajoara and a putative phylogenetic species, An. albitarsis "E." As with the other largely monomorphic species in the complex, we were able to detect its presence using ribosomal DNA internal transcribed spacer 2 (rDNA ITS2) and partial white gene sequences. Unlike An. marajoara, but in common with other species in the complex, An. albitarsis F lacks the white gene fourth intron. This species is sympatric with An. marajoara in a malaria-endemic area in Puerto Carreño, Vichada Department, Colombia. It could be an important current and/or historical vector of human malaria parasites at this locality and, depending on its actual distribution, elsewhere in Colombia and Venezuela.

  7. Larvicidal activity of oak Quercus infectoria Oliv. (Fagaceae) gall extracts against Anopheles stephensi Liston.

    PubMed

    Aivazi, Ali-Ashraf; Vijayan, V A

    2009-06-01

    There is a growing interest in the use of botanical insecticides to reduce the use of synthetic pesticides in order to avoid environmental side effects. Anopheles stephensi is the primary vector of urban malaria, an endemic disease in India. So, an effort to assay An. stephensi larvae with gall extracts of Quercus infectoria was made under laboratory conditions at Mysore. Ethyl-acetate extract was found to be the most effective of all the five extracts tested for larvicidal activity against the fourth instar larvae, with LC(50) of 116.92 ppm followed by gallotannin, n-butanol, acetone, and methanol with LC(50) values of 124.62, 174.76, 299.26, and 364.61 ppm, respectively. The efficacy in killing mosquito larvae may make this plant promising for the development of new botanical larvicide.

  8. Changes in Genetic Diversity from Field to Laboratory During Colonization of Anopheles darlingi Root (Diptera: Culicidae).

    PubMed

    Lainhart, William; Bickersmith, Sara A; Moreno, Marta; Rios, Carlos Tong; Vinetz, Joseph M; Conn, Jan E

    2015-11-01

    The process of colonizing any arthropod species, including vector mosquitoes, necessarily involves adaptation to laboratory conditions. The adaptation and evolution of colonized mosquito populations needs consideration when such colonies are used as representative models for pathogen transmission dynamics. A recently established colony of Anopheles darlingi, the primary malaria vector in Amazonian South America, was tested for genetic diversity and bottleneck after 21 generations, using microsatellites. As expected, laboratory An. darlingi had fewer private and rare alleles (frequency < 0.05), decreased observed heterozygosity, and more common alleles (frequency > 0.50), but no significant evidence of a bottleneck, decrease in total alleles, or increase in inbreeding compared with field specimens (founder population). Low-moderate differentiation between field and laboratory populations was detected. With these findings, and the documented inherent differences between laboratory and field populations, results of pathogen transmission studies using this An. darlingi colony need to be interpreted cautiously.

  9. Changes in Genetic Diversity from Field to Laboratory during Colonization of Anopheles darlingi Root (Diptera: Culicidae)

    PubMed Central

    Lainhart, William; Bickersmith, Sara A.; Moreno, Marta; Rios, Carlos Tong; Vinetz, Joseph M.; Conn, Jan E.

    2015-01-01

    The process of colonizing any arthropod species, including vector mosquitoes, necessarily involves adaptation to laboratory conditions. The adaptation and evolution of colonized mosquito populations needs consideration when such colonies are used as representative models for pathogen transmission dynamics. A recently established colony of Anopheles darlingi, the primary malaria vector in Amazonian South America, was tested for genetic diversity and bottleneck after 21 generations, using microsatellites. As expected, laboratory An. darlingi had fewer private and rare alleles (frequency < 0.05), decreased observed heterozygosity, and more common alleles (frequency > 0.50), but no significant evidence of a bottleneck, decrease in total alleles, or increase in inbreeding compared with field specimens (founder population). Low-moderate differentiation between field and laboratory populations was detected. With these findings, and the documented inherent differences between laboratory and field populations, results of pathogen transmission studies using this An. darlingi colony need to be interpreted cautiously. PMID:26283742

  10. The impact of insecticides management linked with resistance expression in Anopheles spp. populations.

    PubMed

    Silva, Guilherme Liberato da; Pereira, Thiago Nunes; Ferla, Noeli Juarez; Silva, Onilda Santos da

    2016-06-01

    The resistance of some species of Anopheles to chemical insecticides is spreading quickly throughout the world and has hindered the actions of prevention and control of malaria. The main mechanism responsible for resistance in these insects appears to be the target site known as knock-down resistance (kdr), which causes mutations in the sodium channel. Even so, many countries have made significant progress in the prevention of malaria, focusing largely on vector control through long-lasting insecticide nets (LLINs), indoor residual spraying and (IRS) of insecticides. The objective of this review is to contribute with information on the more applied insecticides for the control of the main vectors of malaria, its effects, and the different mechanisms of resistance. Currently it is necessary to look for others alternatives, e.g. biological control and products derived from plants and fungi, by using other organisms as a possible regulator of the populations of malaria vectors in critical outbreaks.

  11. A mosquito lipoxin/lipocalin complex mediates innate immune priming in Anopheles gambiae

    PubMed Central

    Ramirez, Jose Luis; de Almeida Oliveira, Giselle; Calvo, Eric; Dalli, Jesmond; Colas, Romain A.; Serhan, Charles N.; Ribeiro, Jose M.; Barillas-Mury, Carolina

    2015-01-01

    Exposure of Anopheles gambiae mosquitoes to Plasmodium infection enhances the ability of their immune system to respond to subsequent infections. However, the molecular mechanism that allows the insect innate immune system to ‘remember' a previous encounter with a pathogen has not been established. Challenged mosquitoes constitutively release a soluble haemocyte differentiation factor into their haemolymph that, when transferred into Naive mosquitoes, also induces priming. Here we show that this factor consists of a Lipoxin/Lipocalin complex. We demonstrate that innate immune priming in mosquitoes involves a persistent increase in expression of Evokin (a lipid carrier of the lipocalin family), and in their ability to convert arachidonic acid to lipoxins, predominantly Lipoxin A4. Plasmodium ookinete midgut invasion triggers immune priming by inducing the release of a mosquito lipoxin/lipocalin complex. PMID:26100162

  12. In vitro and in vivo host range of Anopheles gambiae densovirus (AgDNV)

    PubMed Central

    Suzuki, Yasutsugu; Barik, Tapan K.; Johnson, Rebecca M.; Rasgon, Jason L.

    2015-01-01

    AgDNV is a powerful gene transduction tool and potential biological control agent for Anopheles mosquitoes. Using a GFP reporter virus system, we investigated AgDNV host range specificity in four arthropod cell lines (derived from An. gambiae, Aedes albopictus and Drosophila melanogaster) and six mosquito species from 3 genera (An. gambiae, An. arabiensis, An. stephensi, Ae. albopictus, Ae. aegypti and Culex tarsalis). In vitro, efficient viral invasion, replication and GFP expression was only observed in MOS55 An. gambiae cells. In vivo, high levels of GFP were observed in An. gambiae mosquitoes. Intermediate levels of GFP were observed in the closely related species An. arabiensis. Low levels of GFP were observed in An. stephensi, Ae. albopictus, Ae. aegypti and Cx. tarsalis. These results suggest that AgDNV is a specific gene transduction tool for members of the An. gambiae species complex, and could be potentially developed into a biocontrol agent with minimal off-target effects. PMID:26220140

  13. Laboratory Evaluation of Temephos against Anopheles stephensi and Culex pipiens Larvae in Iran

    PubMed Central

    Abai, Mohammad Reza; Hanafi-Bojd, Ahmad Ali; Vatandoost, Hassan

    2016-01-01

    Background: Malaria is still a health problem in Iran. There are several vector control activities, including Indoor Residual spraying, using insecticide treated nets and larviciding including Temephos. In addition nuisance mosquitos are prevalent in the urban areas. So that evaluation of this species to larvicide will provide a clue for management of vector control activities. Methods: Two mosquito species were used in this study: Anopheles stephensi were collected from Kazeroun and Culex pipiens from Tehran, capital of Iran. All the tests were carried out according to the WHO method. All the test kis was provided by WHO. Results: Results showed a LC50= 0.0523 and LC90=0.3822 mg/l for An. stephensi. The figure for Cx. pipiens was 0.1838 and 0.8505 mg/l respectively. Conclusion: monitoring of insecticide resistance to Temephos should be evaluated regularly for management of vector control. PMID:28032103

  14. Comparative fitness assessment of Anopheles stephensi transgenic lines receptive to site-specific integration.

    PubMed

    Amenya, D A; Bonizzoni, M; Isaacs, A T; Jasinskiene, N; Chen, H; Marinotti, O; Yan, G; James, A A

    2010-04-01

    Genetically modified mosquitoes that are unable to transmit pathogens offer opportunities for controlling vector-borne diseases such as malaria and dengue. Site-specific gene recombination technologies are advantageous in the development of these insects because antipathogen effector genes can be inserted at integration sites in the genome that cause the least alteration in mosquito fitness. Here we describe Anopheles stephensi transgenic lines containing phi C31 attP'docking' sites linked to a fluorescent marker gene. Chromosomal insertion sites were determined and life-table parameters were assessed for transgenic mosquitoes of each line. No significant differences in fitness between the transgenic and nontransgenic mosquitoes were detected in this study. These transgenic lines are suitable for future site-specific integrations of antiparasite transgenes into the attP sites.

  15. Wolbachia infections in natural Anopheles populations affect egg laying and negatively correlate with Plasmodium development

    PubMed Central

    Shaw, W. Robert; Marcenac, Perrine; Childs, Lauren M.; Buckee, Caroline O.; Baldini, Francesco; Sawadogo, Simon P.; Dabiré, Roch K.; Diabaté, Abdoulaye; Catteruccia, Flaminia

    2016-01-01

    The maternally inherited alpha-proteobacterium Wolbachia has been proposed as a tool to block transmission of devastating mosquito-borne infectious diseases like dengue and malaria. Here we study the reproductive manipulations induced by a recently identified Wolbachia strain that stably infects natural mosquito populations of a major malaria vector, Anopheles coluzzii, in Burkina Faso. We determine that these infections significantly accelerate egg laying but do not induce cytoplasmic incompatibility or sex-ratio distortion, two parasitic reproductive phenotypes that facilitate the spread of other Wolbachia strains within insect hosts. Analysis of 221 blood-fed A. coluzzii females collected from houses shows a negative correlation between the presence of Plasmodium parasites and Wolbachia infection. A mathematical model incorporating these results predicts that infection with these endosymbionts may reduce malaria prevalence in human populations. These data suggest that Wolbachia may be an important player in malaria transmission dynamics in Sub-Saharan Africa. PMID:27243367

  16. [The distribution of the mosquitoes of the Anopheles maculipennis complex (Diptera, Culicidae, Anophelinae) in Central Asia].

    PubMed

    Zvantsov, A B; Gordeev, M I; Goriacheva, I I; Ezhov, M N

    2014-01-01

    The polymerase chain reaction-restriction fragment length polymorphism method, cytogenetic analysis, and investigation of egg exochorion have indicated that three representatives of the Anopheles maculipennis complex (subgenus Anopheles): An artemievi Gordeev et al., An. messeae Falleroni, and An. marinius Shingarev. An. messeae is a European-Siberian species that has extended the southern border of its habitat and has been distributed in the south of Kazakhstan and in the north of Kyrgyzstan. In, Kyrgyzstan, An. messeae inhabiting the plains of Europe and Siberia is encountered rather high up in the mountains: the highest point where this species is found is at 1,879 m above sea level. An. artemievi is present in the highland and piedmont regions of Central Asia (Uzbekistan, Kyrgyzstan, southern Kazakhstan, and northern Tajikistan) and in the intermountain basins (Naryn and Fergana ones). The single finding of this species is in south-eastern Turkmenistan. On the contrary, An. martinius tends to be in the plains and occurs in north-eastern Turkmenistan, Karakalpakstan, and Kazakhstan (Kzyl-Orda). On the other hand, a population of this species is found in proximity to the foothills of the Gissar Range in the east of Uzbekistan. An.maculipennis s.str. is not seen in Central Asia. Early evidence for the presence of both An. maculipennis s.str. and An. martinius in Kopet Dag (Southern Turkmenistan) is rather questionable. It is not improbable that these data are appropriate for either the newly described species An.persiensis or the scientifically new representative of the An. maculipennis complex.

  17. Environmental covariates of Anopheles arabiensis in a rice agroecosystem in Mwea, Central Kenya.

    PubMed

    Mwangangi, Joseph M; Muturi, Ephantus J; Shililu, Josephat I; Muriu, Simon; Jacob, Benjamin; Kabiru, Ephantus W; Mbogo, Charles M; Githure, John I; Novak, Robert J

    2007-12-01

    Water quality of aquatic habitats is an important determinant of female mosquito oviposition and successful larval development. This study examined the influence of environmental covariates on Anopheles arabiensis mosquito abundance in the Mwea Irrigation Scheme, Central Province of Kenya, prior to implementation of a malaria vector control program. Experimental rice plots were used to examine the environmental covariates responsible for regulating abundance and diversity of the aquatic stages of malaria vectors. Mosquito larval sampling and water quality analysis were done weekly from the flooding stage to the rice maturation stage. Sampling for mosquito larvae was conducted using standard dipping technique. During each larval collection, environmental covariates such as pH, temperature, conductivity, salinity, dissolved oxygen, water depth, and rice stage were measured. Anopheles arabiensis larval density was highest between 1 wk before transplanting and 4 wk after transplanting with peaks at weeks 0, 3, and 8. The fluctuation in values of the various environmental covariates showed characteristic patterns in different rice growth phases depending on the changes taking place due to the agronomic practices. Using a backward linear regression model, the factors that were found to be associated with abundance of An. arabiensis larvae at any of the rice growing phases included the following: dissolved oxygen, pH, turbidity, water depth, rice height, number of rice tillers, salinity, conductivity, and temperature. The environmental covariates associated with abundance of An. arabiensis were associated with early vegetative stage of the rice growth. For effective control of developmental stages of mosquito larvae, the application of larvicides should be done at the vegetative stage and the larvicides should persist until the beginning of the reproductive stage of the rice.

  18. Transgenic Expression of the Anti-parasitic Factor TEP1 in the Malaria Mosquito Anopheles gambiae

    PubMed Central

    Hopp, Ann-Katrin; Saenger, Mélanie; Soichot, Julien; Scholze, Heidi; Boch, Jens; Blandin, Stéphanie A.; Marois, Eric

    2017-01-01

    Mosquitoes genetically engineered to be resistant to Plasmodium parasites represent a promising novel approach in the fight against malaria. The insect immune system itself is a source of anti-parasitic genes potentially exploitable for transgenic designs. The Anopheles gambiae thioester containing protein 1 (TEP1) is a potent anti-parasitic protein. TEP1 is secreted and circulates in the mosquito hemolymph, where its activated cleaved form binds and eliminates malaria parasites. Here we investigated whether TEP1 can be used to create malaria resistant mosquitoes. Using a GFP reporter transgene, we determined that the fat body is the main site of TEP1 expression. We generated transgenic mosquitoes that express TEP1r, a potent refractory allele of TEP1, in the fat body and examined the activity of the transgenic protein in wild-type or TEP1 mutant genetic backgrounds. Transgenic TEP1r rescued loss-of-function mutations, but did not increase parasite resistance in the presence of a wild-type susceptible allele. Consistent with previous reports, TEP1 protein expressed from the transgene in the fat body was taken up by hemocytes upon a challenge with injected bacteria. Furthermore, although maturation of transgenic TEP1 into the cleaved form was impaired in one of the TEP1 mutant lines, it was still sufficient to reduce parasite numbers and induce parasite melanization. We also report here the first use of Transcription Activator Like Effectors (TALEs) in Anopheles gambiae to stimulate expression of endogenous TEP1. We found that artificial elevation of TEP1 expression remains moderate in vivo and that enhancement of endogenous TEP1 expression did not result in increased resistance to Plasmodium. Taken together, our results reveal the difficulty of artificially influencing TEP1-mediated Plasmodium resistance, and contribute to further our understanding of the molecular mechanisms underlying mosquito resistance to Plasmodium parasites. PMID:28095489

  19. Polymorphisms in Anopheles gambiae Immune Genes Associated with Natural Resistance to Plasmodium falciparum

    PubMed Central

    Harris, Caroline; Lambrechts, Louis; Rousset, François; Abate, Luc; Nsango, Sandrine E.; Fontenille, Didier; Morlais, Isabelle; Cohuet, Anna

    2010-01-01

    Many genes involved in the immune response of Anopheles gambiae, the main malaria vector in Africa, have been identified, but whether naturally occurring polymorphisms in these genes underlie variation in resistance to the human malaria parasite, Plasmodium falciparum, is currently unknown. Here we carried out a candidate gene association study to identify single nucleotide polymorphisms (SNPs) associated with natural resistance to P. falciparum. A. gambiae M form mosquitoes from Cameroon were experimentally challenged with three local wild P. falciparum isolates. Statistical associations were assessed between 157 SNPs selected from a set of 67 A. gambiae immune-related genes and the level of infection. Isolate-specific associations were accounted for by including the effect of the isolate in the analysis. Five SNPs were significantly associated to the infection phenotype, located within or upstream of AgMDL1, CEC1, Sp PPO activate, Sp SNAKElike, and TOLL6. Low overall and local linkage disequilibrium indicated high specificity in the loci found. Association between infection phenotype and two SNPs was isolate-specific, providing the first evidence of vector genotype by parasite isolate interactions at the molecular level. Four SNPs were associated to either oocyst presence or load, indicating that the genetic basis of infection prevalence and intensity may differ. The validity of the approach was verified by confirming the functional role of Sp SNAKElike in gene silencing assays. These results strongly support the role of genetic variation within or near these five A. gambiae immune genes, in concert with other genes, in natural resistance to P. falciparum. They emphasize the need to distinguish between infection prevalence and intensity and to account for the genetic specificity of vector-parasite interactions in dissecting the genetic basis of Anopheles resistance to human malaria. PMID:20862317

  20. Malaria antifolate resistance with contrasting Plasmodium falciparum dihydrofolate reductase (DHFR) polymorphisms in humans and Anopheles mosquitoes

    PubMed Central

    Mharakurwa, Sungano; Kumwenda, Taida; Mkulama, Mtawa A. P.; Musapa, Mulenga; Chishimba, Sandra; Shiff, Clive J.; Sullivan, David J.; Thuma, Philip E.; Liu, Kun; Agre, Peter

    2011-01-01

    Surveillance for drug-resistant parasites in human blood is a major effort in malaria control. Here we report contrasting antifolate resistance polymorphisms in Plasmodium falciparum when parasites in human blood were compared with parasites in Anopheles vector mosquitoes from sleeping huts in rural Zambia. DNA encoding P. falciparum dihydrofolate reductase (EC 1.5.1.3) was amplified by PCR with allele-specific restriction enzyme digestions. Markedly prevalent pyrimethamine-resistant mutants were evident in human P. falciparum infections—S108N (>90%), with N51I, C59R, and 108N+51I+59R triple mutants (30–80%). This resistance level may be from selection pressure due to decades of sulfadoxine/pyrimethamine use in the region. In contrast, cycloguanil-resistant mutants were detected in very low frequency in parasites from human blood samples—S108T (13%), with A16V and 108T+16V double mutants (∼4%). Surprisingly, pyrimethamine-resistant mutants were of very low prevalence (2–12%) in the midguts of Anopheles arabiensis vector mosquitoes, but cycloguanil-resistant mutants were highly prevalent—S108T (90%), with A16V and the 108T+16V double mutant (49–57%). Structural analysis of the dihydrofolate reductase by in silico modeling revealed a key difference in the enzyme within the NADPH binding pocket, predicting the S108N enzyme to have reduced stability but the S108T enzyme to have increased stability. We conclude that P. falciparum can bear highly host-specific drug-resistant polymorphisms, most likely reflecting different selective pressures found in humans and mosquitoes. Thus, it may be useful to sample both human and mosquito vector infections to accurately ascertain the epidemiological status of drug-resistant alleles. PMID:22065788

  1. Anopheles (Diptera: Culicidae) malaria vectors in the municipality of Puerto Carreno, Vichada, Colombia

    PubMed Central

    Jiménez, Pilar; Conn, Jan E.; Wirtz, Robert; Brochero, Helena

    2013-01-01

    Introduction The study of the biological aspects of Anopheles spp., strengthens the entomological surveillance. Objective To determine biological aspects and behavior of adult Anopheles mosquitoes in the urban area of Puerto Carreño municipality, Vichada, Colombia. Materials and methods Wild anophelines were collected landing on humans both indoors and outdoors between 18:00h and 06:00h for 50 min/h during two consecutive nights/month for eight months in the urban area of Puerto Carreño. The biting rate activity, the natural infection by Plasmodium falciparum and P. vivax VK247 and VK210 using ELISA, and the annual entomological inoculation rate were determined for each species. The members of the Albitarsis complex were determined by amplificacion of the white gene by polymerase chain reaction. Results In order of abundance the species found were An. darlingi (n=1,166), An. marajoara sensu stricto (n=152), An. braziliensis (n=59), An. albitarsis F (n=25), An. albitarsis sensu lato (n=16), An. argyritarsis (n=3) and An. oswaldoi sensu lato (n=2). An. darlingi showed two activity peaks between 21:00 to 22:00 and 05:00 to 06:00 hours outdoors and between 21:00 to 22:00 and 04:00 to 05:00 indoors. Natural infection of this species was found with P. vivax VK210 and its annual entomological inoculation rate was 2. Natural infection of An marajoara sensu stricto with P. falciparum was found, with an annual entomological inoculation rate of 5 and a peak biting activity between 18:00 to 19:00 hrs both indoors and outdoors. Conclusion Transmission of malaria in the urban area of Puerto Carreño, Vichada, can occur by An. darlingi and An. marajoara s. s. PMID:23235809

  2. Cytochrome P450 associated with insecticide resistance catalyzes cuticular hydrocarbon production in Anopheles gambiae

    PubMed Central

    Balabanidou, Vasileia; Kampouraki, Anastasia; MacLean, Marina; Blomquist, Gary J.; Tittiger, Claus; Juárez, M. Patricia; Mijailovsky, Sergio J.; Chalepakis, George; Anthousi, Amalia; Lynd, Amy; Antoine, Sanou; Hemingway, Janet; Ranson, Hilary; Lycett, Gareth J.; Vontas, John

    2016-01-01

    The role of cuticle changes in insecticide resistance in the major malaria vector Anopheles gambiae was assessed. The rate of internalization of 14C deltamethrin was significantly slower in a resistant strain than in a susceptible strain. Topical application of an acetone insecticide formulation to circumvent lipid-based uptake barriers decreased the resistance ratio by ∼50%. Cuticle analysis by electron microscopy and characterization of lipid extracts indicated that resistant mosquitoes had a thicker epicuticular layer and a significant increase in cuticular hydrocarbon (CHC) content (∼29%). However, the CHC profile and relative distribution were similar in resistant and susceptible insects. The cellular localization and in vitro activity of two P450 enzymes, CYP4G16 and CYP4G17, whose genes are frequently overexpressed in resistant Anopheles mosquitoes, were analyzed. These enzymes are potential orthologs of the CYP4G1/2 enzymes that catalyze the final step of CHC biosynthesis in Drosophila and Musca domestica, respectively. Immunostaining indicated that both CYP4G16 and CYP4G17 are highly abundant in oenocytes, the insect cell type thought to secrete hydrocarbons. However, an intriguing difference was indicated; CYP4G17 occurs throughout the cell, as expected for a microsomal P450, but CYP4G16 localizes to the periphery of the cell and lies on the cytoplasmic side of the cell membrane, a unique position for a P450 enzyme. CYP4G16 and CYP4G17 were functionally expressed in insect cells. CYP4G16 produced hydrocarbons from a C18 aldehyde substrate and thus has bona fide decarbonylase activity similar to that of dmCYP4G1/2. The data support the hypothesis that the coevolution of multiple mechanisms, including cuticular barriers, has occurred in highly pyrethroid-resistant An. gambiae. PMID:27439866

  3. Anopheles Midgut Epithelium Evades Human Complement Activity by Capturing Factor H from the Blood Meal

    PubMed Central

    Khattab, Ayman; Barroso, Marta; Miettinen, Tiera; Meri, Seppo

    2015-01-01

    Hematophagous vectors strictly require ingesting blood from their hosts to complete their life cycles. Exposure of the alimentary canal of these vectors to the host immune effectors necessitates efficient counteractive measures by hematophagous vectors. The Anopheles mosquito transmitting the malaria parasite is an example of hematophagous vectors that within seconds can ingest human blood double its weight. The innate immune defense mechanisms, like the complement system, in the human blood should thereby immediately react against foreign cells in the mosquito midgut. A prerequisite for complement activation is that the target cells lack complement regulators on their surfaces. In this work, we analyzed whether human complement is active in the mosquito midgut, and how the mosquito midgut cells protect themselves against complement attack. We found that complement remained active for a considerable time and was able to kill microbes within the mosquito midgut. However, the Anopheles mosquito midgut cells were not injured. These cells were found to protect themselves by capturing factor H, the main soluble inhibitor of the alternative complement pathway. Factor H inhibited complement on the midgut cells by promoting inactivation of C3b to iC3b and preventing the activity of the alternative pathway amplification C3 convertase enzyme. An interference of the FH regulatory activity by monoclonal antibodies, carried to the midgut via blood, resulted in increased mosquito mortality and reduced fecundity. By using a ligand blotting assay, a putative mosquito midgut FH receptor could be detected. Thereby, we have identified a novel mechanism whereby mosquitoes can tolerate human blood. PMID:25679788

  4. The contribution of aestivating mosquitoes to the persistence of Anopheles gambiae in the Sahel

    PubMed Central

    2011-01-01

    Background Persistence of African anophelines throughout the long dry season (4-8 months) when no surface waters are available remains one of the enduring mysteries of medical entomology. Recent studies demonstrated that aestivation (summer diapause) is one mechanism that allows the African malaria mosquito, Anopheles gambiae, to persist in the Sahel. However, migration from distant localities - where reproduction continues year-round - might also be involved. Methods To assess the contribution of aestivating adults to the buildup of populations in the subsequent wet season, two villages subjected to weekly pyrethrum sprays throughout the dry season were compared with two nearby villages, which were only monitored. If aestivating adults are the main source of the subsequent wet-season population, then the subsequent wet-season density in the treated villages will be lower than in the control villages. Moreover, since virtually only M-form An. gambiae are found during the dry season, the reduction should be specific to the M form, whereas no such difference is predicted for S-form An. gambiae or Anopheles arabiensis. On the other hand, if migrants arriving with the first rain are the main source, no differences between treated and control villages are expected across all members of the An. gambiae complex. Results The wet-season density of the M form in treated villages was 30% lower than that in the control (P < 10-4, permutation test), whereas no significant differences were detected in the S form or An. arabiensis. Conclusions These results support the hypothesis that the M form persist in the arid Sahel primarily by aestivation, whereas the S form and An. arabiensis rely on migration from distant locations. Implications for malaria control are discussed. PMID:21645385

  5. Genome-Wide Transcriptional Analysis of Genes Associated with Acute Desiccation Stress in Anopheles gambiae

    PubMed Central

    Wang, Mei-Hui; Marinotti, Osvaldo; Vardo-Zalik, Anne; Boparai, Rajni; Yan, Guiyun

    2011-01-01

    Malaria transmission in sub-Saharan Africa varies seasonally in intensity. Outbreaks of malaria occur after the beginning of the rainy season, whereas, during the dry season, reports of the disease are less frequent. Anopheles gambiae mosquitoes, the main malaria vector, are observed all year long but their densities are low during the dry season that generally lasts several months. Aestivation, seasonal migration, and local adaptation have been suggested as mechanisms that enable mosquito populations to persist through the dry season. Studies of chromosomal inversions have shown that inversions 2La, 2Rb, 2Rc, 2Rd, and 2Ru are associated with various physiological changes that confer aridity resistance. However, little is known about how phenotypic plasticity responds to seasonally dry conditions. This study examined the effects of desiccation stress on transcriptional regulation in An. gambiae. We exposed female An. gambiae G3 mosquitoes to acute desiccation and conducted a genome-wide analysis of their transcriptomes using the Affymetrix Plasmodium/Anopheles Genome Array. The transcription of 248 genes (1.7% of all transcripts) was significantly affected in all experimental conditions, including 96 with increased expression and 152 with decreased expression. In general, the data indicate a reduction in the metabolic rate of mosquitoes exposed to desiccation. Transcripts accumulated at higher levels during desiccation are associated with oxygen radical detoxification, DNA repair and stress responses. The proportion of transcripts within 2La and 2Rs (2Rb, 2Rc, 2Rd, and 2Ru) (67/248, or 27%) is similar to the percentage of transcripts located within these inversions (31%). These data may be useful in efforts to elucidate the role of chromosomal inversions in aridity tolerance. The scope of application of the anopheline genome demonstrates that examining transcriptional activity in relation to genotypic adaptations greatly expands the number of candidate regions

  6. Desiccation tolerance in Anopheles coluzzii: the effects of spiracle size and cuticular hydrocarbons

    PubMed Central

    Arcaz, Arthur C.; Huestis, Diana L.; Dao, Adama; Yaro, Alpha S.; Diallo, Moussa; Andersen, John; Blomquist, Gary J.; Lehmann, Tovi

    2016-01-01

    ABSTRACT The African malaria mosquitoes Anopheles gambiae and Anopheles coluzzii range over forests and arid areas, where they withstand dry spells and months-long dry seasons, suggesting variation in their desiccation tolerance. We subjected a laboratory colony (G3) and wild Sahelian mosquitoes during the rainy and dry seasons to desiccation assays. The thoracic spiracles and amount and composition of cuticular hydrocarbons (CHCs) of individual mosquitoes were measured to determine the effects of these traits on desiccation tolerance. The relative humidity of the assay, body water available, rate of water loss and water content at death accounted for 88% of the variation in desiccation tolerance. Spiracle size did not affect the rate of water loss or desiccation tolerance of the colony mosquitoes, as was the case for the total CHCs. However, six CHCs accounted for 71% of the variation in desiccation tolerance and three accounted for 72% of the variation in the rate of water loss. Wild A. coluzzii exhibited elevated desiccation tolerance during the dry season. During that time, relative thorax and spiracle sizes were smaller than during the rainy season. A smaller spiracle size appeared to increase A. coluzzii's desiccation tolerance, but was not statistically significant. Seasonal changes in CHC composition were detected in Sahelian A. coluzzii. Stepwise regression models suggested the effect of particular CHCs on desiccation tolerance. In conclusion, the combination of particular CHCs along with the total amount of CHCs is a primary mechanism conferring desiccation tolerance in A. coluzzii, while variation in spiracle size might be a secondary mechanism. PMID:27207644

  7. Effectiveness of aerial- and ground-applied Bacillus formulations against Anopheles quadrimaculatus larvae in Arkansas rice plots.

    PubMed

    Dennett, J A; Meisch, M V

    2000-09-01

    Experimental Bacillus larvicides designed to float on or near the water surface were compared to labeled standard Bacillus corn-cob-based larvicides using sentinel Anopheles quadrimaculatus larvae in Arkansas rice plots during the 1998 growing season. Experimental floating formulations of Bacillus thuringiensis israelensis applied at 5.58 and 11.18 kg/ha provided up to 100% control of 3rd- and 4th-stage Anopheles larvae within 24-48 h, whereas the water-dispersible granule formulations containing Bacillus sphaericus required 48-72 h to yield >75% mortality in 0.16-ha plots at 11.18 kg/ha. Detecting and targeting the smaller developmental stages (1st- and 2nd-stage larvae) could increase the effectiveness of the tested compounds against An. quadrimaculatus in Arkansas and other rice-growing regions.

  8. Susceptibility of three laboratory strains of Anopheles albimanus (Diptera: Culicidae) to coindigenous Plasmodium vivax in southern Mexico.

    PubMed

    Chan, A S; Rodríguez, M H; Torres, J A; Rodríguez, M del C; Villarreal, C

    1994-05-01

    Three morphologically different pupal phenotypes (green, striped, brown) were selected from a parent strain of Anopheles albimanus Wiedemann collected from the Suchiate region in the state of Chiapas, Mexico. Significant differences in susceptibility to coindigenous Plasmodium vivax Grassi & Feletti were observed when striped was compared with the parent colony as well as with brown and with green phenotypes. Differences in susceptibility were not significant between the other phenotypes and the parent colony.

  9. Remotely-sensed land use patterns and the presence of Anopheles larvae (Diptera: Culicidae) in Sukabumi, West Java, Indonesia.

    PubMed

    Stoops, Craig A; Gionar, Yoyo R; Shinta; Sismadi, Priyanto; Rachmat, Agus; Elyazar, Iqbal F; Sukowati, Supratman

    2008-06-01

    Land use patterns and the occurrence of Anopheles species larvae were studied in Sukabumi District, West Java, Indonesia, from October 2004 to September 2005. Two land use maps derived using remote sensing were used. One map derived from Quickbird satellite images of 150 km2 of the Simpenan and Ciemas subdistricts (106 degrees 27' 53"-106 degrees 38' 38" E and 6 degrees 59' 59"-7 degrees 8' 46" S) in Sukabumi and one using ASTER images covering 4,000 km2 of Sukabumi District from 106 degrees 22' 15"-107 degrees 4' 1" E and 6 degrees 42' 50" - 7 degrees 26' 13" S. There was a total of 11 Anopheles spp. collected from 209 sampling locations in the area covered by the Quickbird image and a total of 15 Anopheles spp. collected from 1,600 sampling locations in the area covered by the ASTER map. For the area covered by the land use maps, ten species were found to have statistically positive relationships between land use class and species presence: Anopheles aconitus, An. annularis, An. barbirostris. An. flavirostris, An. insulaeflorum, An. kochi, An. maculatus, An. subpictus, An. sundaicus, and An. vagus. Quickbird and ASTER satellite images both produced land maps that were adequate for predicting species presence in an area. The land use classes associated with malaria vector breeding were rice paddy (An. aconitus, An. subpictus), plantation located near or adjacent to human settlements (An. maculatus), bush/shrub (An. aconitus, An. maculatus, An. sundaicus), bare land, and water body land use on the coast located < or = 250 m of the beach (An. sundaicus). Understanding the associations of habitat and species in one area, predictions of species presence or absence can be made prior to a ground survey allowing for accurate vector survey and control planning.

  10. Anopheles lindesayi japonicus Yamada (Diptera: Culicidae) in Korea: comprehensive review, new collection records, and description of larval habitats

    DTIC Science & Technology

    2007-09-01

    3North Carolina Department ofEnvironment and Natural Resources. 585 Waughtown St.• Winston-Salem. NC 27107, U.S.A. fKorea Center for Disease Control ...Seou~ Korea Received 13 September 2007; Accepted 29 December 2007 ABSTRACf: Anopheles lindesayi japonicus Yamada is an uncommonly collected mosquito ...in Korea. and its presence is based upon limited collection data and anecdotal reports in Korean mosquito literature: 45 specimens collected from 15

  11. Efficacy of Bacillus thuringiensis var. Kurstaki in the control of two mosquito species (Anopheles stephensi and Culex quinquefasciatus).

    PubMed

    Kumar, A Senthil; Moorthi, M; Ramakrishnan, N; Dhanapakiam, P; Ramasamy, V K; Rajeswari, A Raja

    2009-05-01

    Bioinsecticide Bacillus thuringiensis var. kurstaki (Btk) was used for controlling the mosquito species (Anopheles stephensi and Culex quinquefasciatus) which gave a significant (p<0.05) mortality in both species. The higher concentration of Btk was highly effective compared to the control ones. The controlling effect was dose and time dependent. Among the studied mosquitoes the C. quinquefasciatus (LC5 0.154%) was more susceptible than A. stephensi (LC50 0.372%) towards the bioinsecticide Btk.

  12. Larvicidal potential of carvacrol and terpinen-4-ol from the essential oil of Origanum vulgare (Lamiaceae) against Anopheles stephensi, Anopheles subpictus, Culex quinquefasciatus and Culex tritaeniorhynchus (Diptera: Culicidae).

    PubMed

    Govindarajan, Marimuthu; Rajeswary, Mohan; Hoti, S L; Benelli, Giovanni

    2016-02-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. However, the use of synthetic insecticides to control Culicidae may lead to resistance, high operational costs and adverse non-target effects. Nowadays, plant-borne mosquitocides may serve as suitable alternative in the fight against mosquito vectors. In this study, the mosquito larvicidal activity of Origanum vulgare (Lamiaceae) leaf essential oil (EO) and its major chemical constituents was evaluated against the malaria vectors Anopheles stephensi and An. subpictus, the filariasis vector Culex quinquefasciatus and the Japanese encephalitis vector Cx. tritaeniorhynchus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the essential oil of O. vulgare contained 17 compounds. The major chemical components were carvacrol (38.30%) and terpinen-4-ol (28.70%). EO had a significant toxic effect against early third-stage larvae of An. stephensi, An. subpictus, Cx. quinquefasciatus and Cx. tritaeniorhynchus, with LC50 values of 67.00, 74.14, 80.35 and 84.93 μg/ml. The two major constituents extracted from the O. vulgare EO were tested individually for acute toxicity against larvae of the four mosquito vectors. Carvacrol and terpinen-4-ol appeared to be most effective against An. stephensi (LC50=21.15 and 43.27 μg/ml, respectively) followed by An. subpictus (LC50=24.06 and 47.73 μg/ml), Cx. quinquefasciatus (LC50=26.08 and 52.19 μg/ml) and Cx. tritaeniorhynchus (LC50=27.95 and 54.87 μg/ml). Overall, this research adds knowledge to develop newer and safer natural larvicides against malaria, filariasis and Japanese encephalitis mosquito vectors.

  13. The Role of Oxidative Stress in the Longevity and Insecticide Resistance Phenotype of the Major Malaria Vectors Anopheles arabiensis and Anopheles funestus.

    PubMed

    Oliver, Shüné V; Brooke, Basil D

    2016-01-01

    Oxidative stress plays numerous biological roles, both functional and pathological. The role of oxidative stress in various epidemiologically relevant biological traits in Anopheles mosquitoes is not well established. In this study, the effects of oxidative stress on the longevity and insecticide resistance phenotype in the major malaria vector species An. arabiensis and An. funestus were examined. Responses to dietary copper sulphate and hydrogen peroxide were used as proxies for the oxidative stress phenotype by determining the effect of copper on longevity and hydrogen peroxide lethal dose. Glutathione peroxidase and catalase activities were determined colorimetrically. Oxidative burden was quantified as protein carbonyl content. Changes in insecticide resistance phenotype were monitored by WHO bioassay. Insecticide resistant individuals showed an increased capacity for coping with oxidative stress, mediated by increased glutathione peroxidase and catalase activity. This effect was observed in both species, as well as in laboratory strains and F1 individuals derived from wild-caught An. funestus mothers. Phenotypic capacity for coping with oxidative stress was greatest in strains with elevated Cytochrome P450 activity. Synergism of oxidative stress defence enzymes by dietary supplementation with haematin, 3-Amino-1, 2, 4-triazole and Sodium diethyldithiocarbamate significantly increased pyrethroid-induced mortality in An. arabiensis and An. funestus. It is therefore concluded that defence against oxidative stress underlies the augmentation of the insecticide resistance phenotype associated with multiple blood-feeding. This is because multiple blood-feeding ultimately leads to a reduction of oxidative stress in insecticide resistant females, and also reduces the oxidative burden induced by DDT and pyrethroids, by inducing increased glutathione peroxidase activity. This study highlights the importance of oxidative stress in the longevity and insecticide resistance

  14. [Distribution of species and kdr gene frequency among Anopheles gambiae s.s. and Anopheles coluzzii populations in five agricultural sites in Côte d'Ivoire].

    PubMed

    Tia, E; Chouaibou, M; Gbalégba, C N G; Boby, A M O; Koné, M; Kadjo, A K

    2017-03-29

    The resistance of Anopheles gambiae s.l. to insecticides constitutes a concern for the programs of malaria control because it can be an obstacle to effective control of the vectors. The follow-up of this resistance is a priority to work out strategies of management and to preserve the means of that major malaria vector control activities. The general objective of this study is to identify the species within An. gambiae s.l., and to determine the frequency of the Kdr gene in An. gambiae s.s. and An. coluzzii in five agricultural sites in Ivory Coast: an urban site, two semirural sites (coffee-trees/cacao-trees, orchard) and two rural sites (rice site and a traditional village without agricultural insecticide). During this study, 2285 specimens of An. gambiae s.l. were analyzed for this purpose. An. gambiae s.s. (in the past called molecular form S) and An. coluzzii (in the past called molecular form M) were the only species of the complex An. gambiae identified in all the sites. The frequency of the Kdr mutation varied from 0.37 in the site without agricultural insecticide to 0.95 in the urban site where there is an intense use of insecticides. Three areas of these species distribution were observed: an area where the species An. gambiae s.s. is dominant (sites located in savanna), an area with predominance of An. coluzzii (in the southern forested area) and an intermediate area where the two species were in a same proportion (pre-forested site).The Kdr mutation was identified in the two species in all the sites in savanna and forest, except in the site without agricultural insecticide where only An. gambiae was resistant. It shows the increase of the receptive potential of An. gambiae s.l. with respect to the Kdr gene and the extension of the resistance to insecticide of this species in Ivory Coast.

  15. [Temporary evolutions of flies anopheles in high altitude region of Lwiro-Katana (Democratic Republic of the Congo)].

    PubMed

    Bandibabone, B J; Zawadi, M B; Ntale, M V; Habamungu, C C; Ombeni, B L

    2016-02-01

    This study has been done with the objective of knowing more about the Anopheles evolutions situation at Lwiro-Katana from 1967 up to 2014. On seven species identified in this region, only four were permanent in nine investigations done. The geometric average calculated shows the evolution of 3.152 for Anopheles funestus, 2.867 for An. gambiae, 2.663 for An. demeilloni and 2.441 for An. marshallii. These species share almost the same ecological conditions for their larval development found in different kinds of water. These conditions were created by the anthropisation of the region followed by some activities. The increasing process attests that An. funestus, An. gambiae and An. demeilloni have an increasing tendency while An. marshallii has a decreasing tendency and is likely to approach the 0 level. An. coustani and An. christyi miss the stability development due to the environmental pertubations since 1980 in this environment. An. kingi wasn't identified after 1980. All of these species of anopheles share the same ecological niche and present a scientific interest. The knowledge of their evolution in this area is really very important because it helps to have better vector control. Also three of those mosquitos (An. gambiae, An. funestus and An. marshallii) are the greatest responsible of the killing paludism South of the Sahara.

  16. Species composition and natural infectivity of anthropophilic Anopheles (Diptera: Culicidae) in Córdoba and Antioquia states in northwestern Colombia

    PubMed Central

    Gutiérrez, Lina A; González, John J; Gómez, Giovan F; Castro, Martha I; Rosero, Doris A; Luckhart, Shirley; Conn, Jan E; Correa, Margarita M

    2011-01-01

    Malaria is a serious health problem in Córdoba and Antioquia states in northwestern Colombia, where 64.4% of the total Colombian cases were reported in 2007. Because little entomological information is available in this region, the aim of this work was to identify the Anopheles species composition and natural infectivity of mosquitoes distributed in seven localities with the highest malaria transmission. A total of 1,768 Anopheles mosquitoes were collected using human landing catches from March 2007 to July 2008. Ten species were identified; overall, An. nuneztovari s.l. was the most widespread (62%) and showed the highest average human biting rates. There were six other species of the Nyssorhynchus subgenus: An. albimanus (11.6%), An. darlingi (9.8%), An. braziliensis (6.6%), An. triannulatus s.l. (3.5%), An. albitarsis s.l. and An. oswaldoi s.l. at <1%; and three of the Anopheles subgenus: An. punctimacula, An. pseudopunctipennis s.l. and An. neomaculipalpus at <1% each. Two species from Córdoba, An. nuneztovari and An. darlingi, were detected naturally infected by Plasmodium vivax VK247 using ELISA and confirmed by nested PCR. All species were active indoors and outdoors. These results provide basic information for targeted vector control strategies in these localities. PMID:20140372

  17. Spatio-temporal variations of Anopheles coluzzii and An. gambiae and their Plasmodium infectivity rates in Lobito, Angola.

    PubMed

    Carnevale, Pierre; Toto, Jean-Claude; Besnard, Patrick; Santos, Maria Adelaide Dos; Fortes, Filomeno; Allan, Richard; Manguin, Sylvie

    2015-06-01

    From 2003 to 2007, entomological surveys were conducted in Lobito town (Benguela Province, Angola) to determine which Anopheles species were present and to identify the vectors responsible for malaria transmission in areas where workers of the Sonamet Company live. Two types of surveys were conducted: (1) time and space surveys in the low and upper parts of Lobito during the rainy and dry periods; (2) a two-year longitudinal study in Sonamet workers' houses provided with long-lasting insecticide-treated nets (LLIN), "PermaNet," along with the neighboring community. Both species, An. coluzzii (M molecular form) and An. gambiae (S molecular form), were collected. Anopheles coluzzii was predominant during the dry season in the low part of Lobito where larvae develop in natural ponds and temporary pools. However, during the rainy season, An. gambiae was found in higher proportions in the upper part of the town where larvae were collected in domestic water tanks built near houses. Anopheles melas and An. listeri were captured in higher numbers during the dry season and in the low part of Lobito where larvae develop in stagnant brackish water pools. The infectivity rates of An. gambiae s.l. varied from 0.90% to 3.41%.

  18. Larvicidal activity of Cymbopogon citratus (DC) Stapf. and Croton macrostachyus Del. against Anopheles arabiensis Patton, a potent malaria vector.

    PubMed

    Karunamoorthi, K; Ilango, K

    2010-01-01

    Methanol leaf extracts of two Ethiopian traditional medicinal plants viz., Lomisar [vernacular name (local native language, Amharic); Cymbopogon citratus (DC) Stapf. (Poaceae)] and Bisana [vernacular name (local native language, Amharic); Croton macrostachyus Del. (Euphorbiaceae)] were screened for larvicidal activity against late third instar larvae of Anopheles arabiensis Patton, a potent malaria vector in Ethiopia. The larval mortality was observed 24 h of post treatment. Both plant extracts demonstrated varying degrees of larvicidal activity against Anopheles arabiensis. Cymbopogon citratus extract has exhibited potent larvicidal activity than Croton macrostachyus at lower concentrations. The LC50 and LC90 values of Cymbopogon citratus were 74.02 and 158.20 ppm, respectively. From this data, a chi-square value 2.760 is significant at the P < 0.05 level. While, the LC50 and LC90 values of Croton macrostachyus were 89.25 and 224.98 ppm, respectively and the chi-square value 1.035 is significant at the P < 0.05 level. The present investigation establishes that these plant extracts could serve as potent mosquito larvicidal agents against Anopheles arabiensis. However, their mode of actions and larvicidal efficiency under the field conditions should be scrutinized and determined in the near future.

  19. Identification of morphological and chemical markers of dry- and wet-season conditions in female Anopheles gambiae mosquitoes

    PubMed Central

    2014-01-01

    Background Increased understanding of the dry-season survival mechanisms of Anopheles gambiae in semi-arid regions could benefit vector control efforts by identifying weak links in the transmission cycle of malaria. In this study, we examined the effect of photoperiod and relative humidity on morphologic and chemical traits known to control water loss in mosquitoes. Methods Anopheles gambiae body size (indexed by wing length), mesothoracic spiracle size, and cuticular hydrocarbon composition (both standardized by body size) were examined in mosquitoes raised from eggs exposed to short photoperiod and low relative humidity, simulating the dry season, or long photoperiod and high relative humidity, simulating the wet-season. Results Mosquitoes exposed to short photoperiod exhibited larger body size and larger mesothoracic spiracle length than mosquitoes exposed to long photoperiod. Mosquitoes exposed to short photoperiod and low relative humidity exhibited greater total cuticular hydrocarbon amount than mosquitoes exposed to long photoperiod and high relative humidity. In addition, total cuticular hydrocarbon amount increased with age and was higher in mated females. Mean n-alkane retention time (a measure of cuticular hydrocarbon chain length) was lower in mosquitoes exposed to short photoperiod and low relative humidity, and increased with age. Individual cuticular hydrocarbon peaks were examined, and several cuticular hydrocarbons were identified as potential biomarkers of dry- and wet-season conditions, age, and insemination status. Conclusions Results from this study indicate that morphological and chemical changes underlie aestivation of Anopheles gambiae and may serve as biomarkers of aestivation. PMID:24970701

  20. A longitudinal study on Anopheles mosquito larval abundance in distinct geographical and environmental settings in western Kenya

    PubMed Central

    2011-01-01

    Background As the ecology of mosquito larvae can be complex there is need to develop a rational framework for undertaking larval ecological studies. Local environmental characteristics, such as altitude, climate and land use, can significantly impact on phenology and population dynamics of mosquito larvae, and indirectly affect the dynamics of mosquito-borne diseases. The aim of this study was to assess the feasibility of implementing an integrated approach to larval source management under the distinct ecological settings. Methods The study was conducted in two highland villages and one village, at a lower altitude, in the Lake Victoria basin, where malaria is endemic and transmitted by the same Anopheles mosquito species. In each village the stability of mosquito larval habitats was classified as either temporary or permanent. The productivity of these habitat types was quantified by carrying out weekly larval sampling using a standard dipping method for a period of two years. During sampling the physical characteristic of the larval habitat, including the vegetation cover were noted. Ambient temperature, rainfall and relative humidity were recorded on a 21 × Micro-datalogger in each study site. Results Anopheles gambiae sensu lato larvae were found in all study sites. Anopheles arabiensis was more abundant (93%) in Nyalenda (Lake Victoria basin) and Fort Ternan (highland area; 71%). In Lunyerere (highland area), An. gambiae sensu stricto comprised 93% of the total An. gambiae s.l. larvae. Larvae of An. gambiae s.l. mosquitoes were present in both temporary and permanent habitats with monthly variations dependent on rainfall intensity and location. Anopheles larvae were more likely to be found in man-made as opposed to natural habitats. Grassy habitats were preferred and were, therefore, more productive of Anopheles larvae compared to other habitat types. Weekly rainfall intensity led to an increase or decrease in mosquito larval abundance depending on the

  1. Larval habitats of Anopheles species in a rural settlement on the malaria frontier of southwest Amazon, Brazil.

    PubMed

    Rufalco-Moutinho, Paulo; Schweigmann, Nicolás; Bergamaschi, Denise Pimentel; Mureb Sallum, Maria Anice

    2016-12-01

    Rural settlements are social arrangements expanding in the Amazon region, which generate disturbances in the natural environment, thus affecting the ecology of the species of Anopheles and thus the malaria transmission. Larval habitats are important sources for maintenance of mosquito vector populations, and holding back a natural watercourse is a usual process in the establishment of rural settlements, since the formation of micro-dams represents a water resource for the new settlers. Identifying characteristics of the larval habitats that may be associated with both the presence and abundance of Anopheles vectors species in an environment under ecological transition is background for planning vector control strategies in rural areas in the Amazon. Anopheles larvae collections were performed in two major types of habitats: natural and flow-limited water collections that were constructed by holding back the original watercourse. A total of 3123 Anopheles spp. larvae were captured in three field-sampling collections. The majority of the larvae identified were taken from flow-limited water collections belonged to species of the Nyssorhynchus subgenus (92%), whereas in the natural larval habitats a fewer number of individuals belonged to the Stethomyia (5%) and Anopheles (3%) subgenera. The total of Nyssorhynchus identified (1818), 501 specimens belonged to An. darlingi, 750 to An. triannulatus and 567 for others remaining species. In addition, 1152 could not be identified to subgenus/species level, because they were either in the first-instar or damaged. The primary vector in areas of the Amazon river basin, An. darlingi, was found exclusively in man-made habitats. Statistical analysis display An. triannulatus with specialist behavior for characteristics of man-made habitats. Modifications in the natural environment facilitate the rise of larval habitats for species with epidemiological importance for malaria in the region. This study showed that man-made habitats

  2. [The Anopheles gambiae species complex and Kdr resistance gene at the periphery of Douala, Cameroon].

    PubMed

    Ntonga Akono, P; Mbouangoro, A; Mbida Mbida, A; Ndo, C; Peka Nsangou, M F; Kekeunou, S

    2017-03-16

    This study was conducted from May to June 2015 in Yassa (industrialized area) and Logbessou (non-industrialized area), two peri-urban areas of the city of Douala, Cameroon with the aim of an assessment of the spatial distribution of the gambiae complex, the determination of their resistance to insecticides and the distribution of the Kdr mutation. Mosquito larvae were collected by the dipping method and nursed to adult stage. The sensitivity of adult Anopheles gambiae s.l. populations to DDT and pyrethroids was assessed following WHO protocol. All tested mosquitoes were identified by PCR SINE. Only survivors were used to search for the Kdr mutation. In both areas, the gambiae complex included An. coluzzii and An. gambiae sympatric in their breeding sites. However, An. gambiae was predominant in Logbessou (88%) and An. coluzzii in Yassa (68%). Tests with deltamethrin, permethrin and DDT revealed mortality rates below 90% regardless of the area of origin of the mosquitoes. PCR diagnosis of Kdr mutation showed that over 95% of survivors harbored the Kdr gene in both sites, with resistant allele frequencies ranging from 0.96 to 1.0 in An. gambiae and from 0.89 to 0.96 in An. coluzzii. The strong resistance of An. coluzzii and This study was conducted from May to June 2015 in Yassa (industrialized area) and Logbessou (nonindustrialized area), two peri-urban areas of the city of Douala, Cameroon with the aim of an assessment of the spatial distribution of the gambiae complex, the determination of their resistance to insecticides and the distribution of the Kdr mutation. Mosquito larvae were collected by the dipping method and nursed to adult stage. The sensitivity of adult Anopheles gambiae s.l. populations to DDT and pyrethroids was assessed following WHO protocol. All tested mosquitoes were identified by PCR SINE. Only survivors were used to search for the Kdr mutation. In both areas, the gambiae complex included An. coluzzii and An. gambiae sympatric in their breeding

  3. Satellite-derived NDVI, LST, and climatic factors driving the distribution and abundance of Anopheles mosquitoes in a former malarious area in northwest Argentina.

    PubMed

    Dantur Juri, María Julia; Estallo, Elizabet; Almirón, Walter; Santana, Mirta; Sartor, Paolo; Lamfri, Mario; Zaidenberg, Mario

    2015-06-01

    Distribution and abundance of disease vectors are directly related to climatic conditions and environmental changes. Remote sensing data have been used for monitoring environmental conditions influencing spatial patterns of vector-borne diseases. The aim of this study was to analyze the effect of the Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS), and climatic factors (temperature, humidity, wind velocity, and accumulated rainfall) on the distribution and abundance of Anopheles species in northwestern Argentina using Poisson regression analyses. Samples were collected from December, 2001 to December, 2005 at three localities, Aguas Blancas, El Oculto and San Ramón de la Nueva Orán. We collected 11,206 adult Anopheles species, with the major abundance observed at El Oculto (59.11%), followed by Aguas Blancas (22.10%) and San Ramón de la Nueva Orán (18.79%). Anopheles pseudopunctipennis was the most abundant species at El Oculto, Anopheles argyritarsis predominated in Aguas Blancas, and Anopheles strodei in San Ramón de la Nueva Orán. Samples were collected throughout the sampling period, with the highest peaks during the spring seasons. LST and mean temperature appear to be the most important variables determining the distribution patterns and major abundance of An. pseudopunctipennis and An. argyritarsis within malarious areas.

  4. Whole-genome sequencing reveals absence of recent gene flow and separate demographic histories for Anopheles punctulatus mosquitoes in Papua New Guinea

    PubMed Central

    LOGUE, KYLE; SMALL, SCOTT T.; CHAN, ERNEST R.; REIMER, LISA; SIBA, PETER M.; ZIMMERMAN, PETER A.; SERRE, DAVID

    2015-01-01

    Anopheles mosquitoes are the vectors of several human diseases including malaria. In many malaria endemic areas, several species of Anopheles coexist, sometimes in the form of related sibling species that are morphologically indistinguishable. Determining the size and organization of Anopheles populations, and possible ongoing gene flow among them is important for malaria control and, in particular, for monitoring the spread of insecticide resistance alleles. However, these parameters have been difficult to evaluate in most Anopheles species due to the paucity of genetic data available. Here, we assess the extent of contemporary gene flow and historical variations in population size by sequencing and de novo assembling the genomes of wild-caught mosquitoes from four species of the Anopheles punctulatus group of Papua New Guinea. Our analysis of more than 50 Mb of orthologous DNA sequences revealed no evidence of contemporary gene flow among these mosquitoes. In addition, investigation of the demography of two of the An. punctulatus species revealed distinct population histories. Overall, our analyses suggest that, despite their similarities in morphology, behaviour and ecology, contemporary sympatric populations of An. punctulatus are evolving independently. PMID:25677924

  5. [Highest mosquito records (Diptera: Culicidae) in Venezuela].

    PubMed

    Navarro, Juan-Carlos; Del Ventura, Fabiola; Zorrilla, Adriana; Liria, Jonathan

    2010-03-01

    Mosquitoes (Diptera: Culicidae) are holometabolous insects with aquatic immature stages, which use a broad variety of larval habitats, from ground water bodies to Phytothelmata (water deposits in plants) and artificial deposits. The availability of breeding sites often determines the upper limits of mosquito ranges. We built a database with 9,607 records with 432 localities, 19 genera and 254 species. The Andean mountains have 77% of the highest mosquito records including Aedes euris with record at 3,133 m, followed by three species of Anopheles--subgenera Kerteszia--with the upper limit of 2,680 m. Wyeomyia bicornis and Culex daumastocampa at 2,550 m were the highest records in the Central-Coastal cordillera, while the highest record in Pantepui was Wyeomyia zinzala at 2,252 m. The species associated with phytothelmata (Bromeliaceae and Sarraceniaceae) represent 60% of the records. The upper limits of Culex quinquefasciatus and Anopheles (Kerteszia) species could represent the theoretical limit for transmission of filariasis or arboviruses, by Culex, and malaria by Anopheles (Kerteszia) in Venezuela. Similarly, a vector of Dengue, Aedes aegypti, has not been not recorded above 2,000 m.

  6. Effect of discriminative plant-sugar feeding on the survival and fecundity of Anopheles gambiae

    PubMed Central

    Manda, Hortance; Gouagna, Louis C; Foster, Woodbridge A; Jackson, Robert R; Beier, John C; Githure, John I; Hassanali, Ahmed

    2007-01-01

    Background A previous study showed for Anopheles gambiae s.s. a gradation of feeding preference on common plant species growing in a malaria holoendemic area in western Kenya. The present follow-up study determines whether there is a relationship between the mosquito's preferences and its survival and fecundity. Methods Groups of mosquitoes were separately given ad libitum opportunity to feed on five of the more preferred plant species (Hamelia patens, Parthenium hysterophorus, Ricinus communis, Senna didymobotrya, and Tecoma stans) and one of the less preferred species (Lantana camara). The mosquitoes were monitored daily for survival. Sugar solution (glucose 6%) and water were used as controls. In addition, the fecundity of mosquitoes on each plant after (i) only one blood meal (number of eggs oviposited), and (ii) after three consecutive blood meals (proportion of females ovipositing, number of eggs oviposited and hatchability of eggs), was determined. The composition and concentration of sugar in the fed-on parts of each plant species were determined using gas chromatography. Using SAS statistical package, tests for significant difference of the fitness values between mosquitoes exposed to different plant species were conducted. Results and Conclusion Anopheles gambiae that had fed on four of the five more preferred plant species (T. stans, S. didymobotrya, R. communis and H. patens, but not P. hysterophorus) lived longer and laid more eggs after one blood meal, when compared with An. gambiae that had fed on the least preferred plant species L. camara. When given three consecutive blood-meals, the percentage of females that oviposited, but not the number of eggs laid, was significantly higher for mosquitoes that had previously fed on the four more preferred plant species. Total sugar concentration in the preferred plant parts was significantly correlated with survival and with the proportion of females that laid eggs. This effect was associated mainly with

  7. Effects of drying eggs and egg storage on hatchability and development of Anopheles arabiensis

    PubMed Central

    2013-01-01

    Background The mass rearing of insects requires a large colony from which individuals can be harvested for sterilization and release. Attention is given to larval food requirements and to handling and rearing conditions to ensure predictability and synchrony of development. Maximizing production requires optimized adult holding to ensure mating success, blood feeding and oviposition. Appropriate egg storage and harvesting is necessary to compensate any unpredicted reduction in egg production. Methods Anopheles arabiensis eggs were collected on wet filter paper in eggs cups. The eggs were cleaned and then dried over a suction device with adjustable speed and time. The effects of drying, storage time and storage condition (wet, dry and bulk with relative humidity 75 ± 5% and storage temperatures of 10, 15 and 20°C) on hatch rate, duration of larval stages (L1 to pupal stage), duration of L1 to adult emergence, survival of L1 to pupal stage and the survival of L1 to adult emergence were investigated. Post drying and post storage hatch rates were determined by counting hatched and unhatched eggs and were confirmed by counting the viable larvae in the rearing medium. Results The hatch rate of eggs dried at wind speeds of 1.0 or 1.8 m/s was not significantly different from the control, but eggs dried at 3.0 m/s resulted in very low (64%) hatchability as compared to the control (82%). Eggs stored at 20°C and 75 ± 5% RH in bulk in an aerated vial showed better survival than eggs stored in wet or dry conditions at 10 or 15°C. No significant changes in larval duration and survival were recorded after six days of bulk storage. Conclusion Anopheles arabiensis eggs can be stored in bulk at 20°C and 75 ± 5% RH for six days without any decrease in hatch rate, and up to 9 days with no impact on larval development. PMID:24028497

  8. De Novo Transcriptome Sequencing in Anopheles funestus Using Illumina RNA-Seq Technology

    PubMed Central

    Crawford, Jacob E.; Guelbeogo, Wamdaogo M.; Sanou, Antoine; Traoré, Alphonse; Vernick, Kenneth D.; Sagnon, N'Fale; Lazzaro, Brian P.

    2010-01-01

    Background Anopheles funestus is one of the primary vectors of human malaria, which causes a million deaths each year in sub-Saharan Africa. Few scientific resources are available to facilitate studies of this mosquito species and relatively little is known about its basic biology and evolution, making development and implementation of novel disease control efforts more difficult. The An. funestus genome has not been sequenced, so in order to facilitate genome-scale experimental biology, we have sequenced the adult female transcriptome of An. funestus from a newly founded colony in Burkina Faso, West Africa, using the Illumina GAIIx next generation sequencing platform. Methodology/Principal Findings We assembled short Illumina reads de novo using a novel approach involving iterative de novo assemblies and “target-based” contig clustering. We then selected a conservative set of 15,527 contigs through comparisons to four Dipteran transcriptomes as well as multiple functional and conserved protein domain databases. Comparison to the Anopheles gambiae immune system identified 339 contigs as putative immune genes, thus identifying a large portion of the immune system that can form the basis for subsequent studies of this important malaria vector. We identified 5,434 1∶1 orthologues between An. funestus and An. gambiae and found that among these 1∶1 orthologues, the protein sequence of those with putative immune function were significantly more diverged than the transcriptome as a whole. Short read alignments to the contig set revealed almost 367,000 genetic polymorphisms segregating in the An. funestus colony and demonstrated the utility of the assembled transcriptome for use in RNA-seq based measurements of gene expression. Conclusions/Significance We developed a pipeline that makes de novo transcriptome sequencing possible in virtually any organism at a very reasonable cost ($6,300 in sequencing costs in our case). We anticipate that our approach could be used

  9. The effects of oviposition-site deprivation on Anopheles gambiae reproduction

    PubMed Central

    2012-01-01

    Background The African malaria mosquito, Anopheles gambiae, depends on availability of suitable surface water for oviposition. Short and long dry spells occur throughout the year in many parts of its range that limit its access to oviposition sites. Although not well understood, oviposition-site deprivation has been found to rapidly reduce egg batch size and hatch rate of several mosquito species. We conducted laboratory experiments to assess these effects of oviposition-site deprivation on An. gambiae and to evaluate the role of nutrition and sperm viability as mediators of these effects. Methods Anopheles gambiae adults (1–2 d old) from the G3 laboratory colony were assigned to the following treatment groups: oviposition-deprived (fed once and then deprived of oviposition site for 7 or 14 d), multiple-fed control (fed regularly once a week and allowed to lay eggs without delay), and age matched blood-deprived control (fed once, three days before water for oviposition was provided). Egg batch size and hatch rate were measured. In the second experiment two additional treatment groups were included: oviposition-deprived females that received either a second (supplemental) blood meal or virgin males (supplemental mating) 4 days prior to receiving water for oviposition. Results An. gambiae was highly sensitive to oviposition-site deprivation. Egg batch size dropped sharply to 0–3.5 egg/female within 14 days, due to reduced oviposition rate rather than a reduced number of eggs/batch. Egg hatch rate also fell dramatically to 0-2% within 7 days. The frequency of brown eggs that fail to tan was elevated. A supplemental blood meal, but not ‘supplemental insemination,’ recovered the oviposition rate of females subjected to oviposition-site deprivation. Similarly, a supplemental blood meal, but not ‘supplemental insemination,’ partly recovered hatch rate, but this increase was marginally significant (P < 0.069). Conclusions Even a short dry spell resulting in

  10. [Malaria, anopheles, the anti-malaria campaign in French Guyana: between dogmatism and judgment].

    PubMed

    Raccurt, C P

    1997-01-01

    The recrudescence of malaria in French Guiana involves both border regions. One notes the predominance of Plasmodium falciparum along the Maroni River on the Surinam frontier and the transmission of both Plasmodium falciparum and Plasmodium vivax in amerindian settlements along the Oyapock River on the Brazilian frontier. The main mosquito vector is the endoexophile species, Anopheles darlingi. The role of man-biting forest anophelines in malaria transmission is still unclear. At the present time, malaria control is based on curative treatment of the confirmed cases (approximately 4,000 cases a year by active and passive screening). Vector control is supported by annual houses insecticides spraying and, to a lesser degree, use of insecticide-impregnated bednets. The main limiting factors for successful control have been difficulty in implementing a strategy adapted to the cultures of the amerindian and bushnegro populations living on either side of the river-frontiers and in organizing effective cross-border cooperation. The alleged role of immigration in transmission dynamics has been more speculative than real. However the growth of the population and the increase of human activities inside rain forest areas have favorized Anopheles darlingi breeding by uncontrolled deforestation. This situation need to be monitored closely. Information campaigns to improve public awareness could be useful. Following measures could improve control in sparsely populated, remote areas: to promote an integrated preventive program for a real community-wide distribution of primary health care; to discontinue insecticides spraying in houses which is poorly accepted by the bushnegro population and unsuitable to the amerindian dwellings; to support the use of personal protection; to initiate an effective anopheline larvae control; to determine the impact of the transmission during day-time activities especially among very small settlements far from the main villages where members of the

  11. Optimization of a Membrane Feeding Assay for Plasmodium vivax Infection in Anopheles albimanus

    PubMed Central

    Vallejo, Andrés F.; Rubiano, Kelly; Amado, Andres; Krystosik, Amy R.; Herrera, Sócrates; Arévalo-Herrera, Myriam

    2016-01-01

    Introduction Individuals exposed to malaria infections for a long time develop immune responses capable of blocking Plasmodium transmission to mosquito vectors, potentially limiting parasite spreading in nature. Development of a malaria TB vaccine requires a better understanding of the mechanisms and main effectors responsible for transmission blocking (TB) responses. The lack of an in vitro culture system for Plasmodium vivax has been an important drawback for development of a standardized method to assess TB responses to this parasite. This study evaluated host, vector, and parasite factors that may influence Anopheles mosquito infection in order to develop an efficient and reliable assay to assess the TB immunity. Methods/Principal Findings A total of 94 P. vivax infected patients were enrolled as parasite donors or subjects of direct mosquito feeding in two malaria endemic regions of Colombia (Tierralta, and Buenaventura). Parasite infectiousness was assessed by membrane feeding assay or direct feeding assay using laboratory reared Anopheles mosquitoes. Infection was measured by qPCR and by microscopically examining mosquito midguts at day 7 for the presence of oocysts. Best infectivity was attained in four day old mosquitoes fed at a density of 100 mosquitos/cage. Membrane feeding assays produced statistically significant better infections than direct feeding assays in parasite donors; cytokine profiles showed increased IFN-γ, TNF and IL-1 levels in non-infectious individuals. Mosquito infections and parasite maturation were more reliably assessed by PCR compared to microscopy. Conclusions We evaluated mosquito, parasite and host factors that may affect the outcome of parasite transmission as measured by artificial membrane feeding assays. Results have led us to conclude that: 1) optimal mosquito infectivity occurs with mosquitoes four days after emergence at a cage density of 100; 2) mosquito infectivity is best quantified by PCR as it may be underestimated

  12. Peri-/intradomicillary behavior in relation to host-seeking of Anopheles pseudopunctipennis in southern Mexico.

    PubMed

    Casas, M; Rodríguez, M H; Bown, D N

    1994-09-01

    Peri-/intradomicillary resting and host-seeking behavior of Anopheles pseudopunctipennis was studied in an experimental house (surrounded by a curtain-net) that had not been sprayed with insecticide. Peak mosquito densities were recorded resting on vegetation 1 h earlier (1900-2000 h) than on the curtain-net, suggesting that a proportion of females prefer resting on adjacent vegetation prior to moving indoors. Between 2000 and 2100 h there was a marked decrease in numbers of mosquitoes resting on the exterior of the curtain-net. In separate experiments without the net, a single peak in numbers of mosquitoes resting on interior surfaces and/or biting human bait occurred between 2000 and 2100 h. Unfed mosquitoes had higher numbers of contacts with wall surfaces than with the roof. Moreover, a higher proportion of mosquitoes collected on human bait had > or = 1 dilatation(s), and higher parity rates than those resting on walls. Higher proportions of parous mosquitoes more frequently fed from 1800 to 2100 h, whereas higher proportions of nulliparous mosquitoes fed during morning hours. Nearly 25% of all mosquitoes exited 1 h following their release inside the house, whereas nearly 7% remained indoors for > 9 h. Overall results demonstrated that the behavior of An. pseudopunctipennis females depends on outdoor/indoor stimuli, being multivariable in nature. This includes contacts with a variety of biological (i.e., vegetation, human) and inert surfaces, which in part appears to be controlled by age structure.

  13. Selective and conventional house-spraying of DDT and bendiocarb against Anopheles pseudopunctipennis in southern Mexico.

    PubMed

    Casas, M; Torres, J L; Bown, D N; Rodríguez, M H; Arredondo-Jiménez, J I

    1998-12-01

    Indoor feeding behaviors and mortalities of Anopheles pseudopunctipennis females were evaluated following contact with selective (bands covering mosquitoes' preferred resting areas) and full applications of DDT and bendiocarb on indoor sprayable surfaces. The DDT residues provoked strong avoidance behavior. To a lesser degree, mosquitoes were also repelled by bendiocarb-sprayed surfaces. Because of strong irritancy/repellency, unfed mosquitoes were driven outdoors in proportionally higher numbers. The resting time on selectively or fully DDT-sprayed huts was greatly reduced in comparison to bendiocarb-sprayed huts. Although unfed mosquitoes tended to rest on non-DDT-sprayed surfaces in the selectively treated hut, the man-biting rate was similar with both types of treatments. Unfed mosquitoes were repelled less from selectively bendiocarb-treated surfaces. Similar reductions in postfed resting times were observed on all surfaces suggesting that once fed, mosquitoes rested on sprayed surfaces for shorter intervals of time. Engorged mosquitoes had normal resting behavior (pre- and postspray) within the range of preferred resting heights in both DDT- and bendiocarb-sprayed huts, but the proportion of mosquitoes fed in the DDT-treated huts was lower. Selective spraying of walls was as effective as spraying the complete walls with both insecticides, but DDT was more effective in reducing mosquito-human contact. These studies show that by more effectively targeting vector behavior, a cost-effective alternative to traditional control techniques can be achieved.

  14. Bacteria in midguts of field-collected Anopheles albimanus block Plasmodium vivax sporogonic development.

    PubMed

    Gonzalez-Ceron, Lilia; Santillan, Frida; Rodriguez, Mario H; Mendez, Domingo; Hernandez-Avila, Juan E

    2003-05-01

    Bacterial infections were investigated in midguts of insectary and field-collected Anopheles albimanus Weidemann from southern Mexico. Serratia marcescens, Enterobacter cloacae and Enterobacter amnigenus 2, Enterobacter sp., and Serratia sp. were isolated in field samples obtained in 1998, but only Enterobacter sp. was recovered in field samples of 1997 and no bacteria were isolated from insectary specimens. These bacteria were offered along with Plasmodium vivax infected blood to aseptic insectary An. albimanus, and the number of infected mosquitoes as well as the oocyst densities assessed after 7d. Plasmodium vivax infections in mosquitoes co-infected with En. amnigenus 2, En. cloacae, and S. marcensces were 53, 17, and 210 times, respectively, lower than in control mosquitoes, and the mean oocyst density in mosquitoes co-infected with En. cloacae was 2.5 times lower than in controls. Mortality was 13 times higher in S. marcensces-infected mosquitoes compared with controls. The overall midgut bacterial infection in mosquito field populations may influence P. vivax transmission, and could contribute to explain the annual variations in malaria incidence observed in the area.

  15. Cyanobacteria associated with Anopheles albimanus (Diptera: Culicidae) larval habitats in southern Mexico.

    PubMed

    Vázquez-Martínez, M Guadalupe; Rodríguez, Mario H; Arredondo-Jiménez, Juan I; Méndez-Sanchez, José D; Bond-Compeán, J Guillermo; Cold-Morgan, Michelle

    2002-11-01

    Cyanobacteria associated with Anopheles albimanus Wiedemann larval habitats from southern Chiapas, Mexico, were isolated and identified from water samples and larval midguts using selective medium BG-11. Larval breeding sites were classified according to their hydrology and dominant vegetation. Cyanobacteria isolated in water samples were recorded and analyzed according to hydrological and vegetation habitat breeding types, and mosquito larval abundance. In total, 19 cyanobacteria species were isolated from water samples. Overall, the most frequently isolated cyanobacterial taxa were Phormidium sp., Oscillatoria sp., Aphanocapsa cf. littoralis, Lyngbya lutea, P. animalis, and Anabaena cf. spiroides. Cyanobacteria were especially abundant in estuaries, irrigation canals, river margins and mangrove lagoons, and more cyanobacteria were isolated from Brachiaria mutica, Ceratophyllum demersum, and Hymenachne amplexicaulis habitats. Cyanobacteria were found in habitats with low to high An. albimanus larval abundance, but Aphanocapsa cf. littoralis was associated with habitats of low larval abundance. No correlation was found between water chemistry parameters and the presence of cyanobacteria, however, water temperature (29.2-29.4 degrees C) and phosphate concentration (79.8-136.5 ppb) were associated with medium and high mosquito larvae abundance. In An. albimanus larval midguts, only six species of cyanobacteria were isolated, the majority being from the most abundant cyanobacteria in water samples.

  16. Landscape surrounding human settlements and Anopheles albimanus (Diptera: Culicidae) abundance in Southern Chiapas, Mexico.

    PubMed

    Rodriguez, A D; Rodriguez, M H; Hernandez, J E; Dister, S W; Beck, L R; Rejmankova, E; Roberts, D R

    1996-01-01

    Landscape characteristics that may influence important components of the Anopheles albimanus Wiedemann life cycle, including potential breeding sites, suitable diurnal resting sites, and possible sources of blood meals, were analyzed at 14 villages in a malarious area of southern Mexico. An. albimanus adults were collected weekly in each village using UV-light traps between July 1991 and August 1992. Based on rainfall, the study was divided into 6 seasonal periods. Villages were considered to have high mosquito abundance when >5 mosquitoes per trap per night were collected during any 1 of the 6 seasonal periods. The extension and frequency of 11 land cover types surrounding villages were determined using aerial photographs and subsequently verified through field surveys. Elevation was the main landscape feature that separated villages with low and high mosquito abundance. All villages with high mosquito abundance were below 25 m. Transitional and mangrove land cover types were found only in the high mosquito abundance group. Flooded areas as potential breeding sites and potential adult resting sites in unmanaged pastures were significantly more frequent in areas surrounding villages with high mosquito abundance. No significant differences in density of cattle and horses were found among village groups. Overall, surrounding breeding sites located at low elevations in flooded unmanaged pastures seemed to be the most important determinants of An. albimanus adult abundance in the villages.

  17. Bionomics of adult Anopheles pseudopunctipennis (Diptera: Culicidae) in the Tapachula foothills area of southern Mexico.

    PubMed

    Fernandez-Salas, I; Rodriguez, M H; Roberts, D R; Rodriguez, M C; Wirtz, R A

    1994-09-01

    Field studies on the bionomics of adult Anopheles pseudopunctipennis Theobald were conducted to assess its relative importance as a primary vector of vivax malaria in southern Mexico. In four malaria endemic villages in a foothill region near Tapachula, Mexico, population densities of A. pseudopunctipennis increased during the dry seasons of 1990 and 1991. The pattern of nocturnal host-seeking activity indoors was unimodal with a late night peak at 0100 hours enhancing its vectorial significance, because it occurred when most residents were asleep and fully exposed to the anophelines. Comparisons of trapping methods showed that a horse-baited trap was more effective than human landing catches or UV light traps. Pit shelters, on the other hand, were more effective than indoor and natural shelter resting collections. Results of enzyme-linked immunosorbent assays performed on wild-caught A. pseudopunctipennis specimens documented the presence of natural infections with the VK210 and new VK247 circumsporozoite polymorphs of P. vivax. These findings verify the importance of A. pseudopunctipennis as a major vector of vivax malaria at higher elevations and extend the geographical range of the VK247 P. vivax polymorph in Mexico.

  18. [Intra-domiciliary low volume spraying of malathion and deltamethrin for controlling Anopheles sp].

    PubMed

    Vaca-Marín, M A; Rodríguez-López, M H; Bown, D N; Ríos, R

    1991-01-01

    The effectiveness of low volume (LV) house-spraying of deltamethrin 0.027 per cent and malathion 20 per cent in the control of Anopheles sp was evaluated in two villages of Tabasco, México during the last semester of 1987. Two spray rounds were carried out at three-month intervals, using Fontan R-12 back-pack-space sprayers. Residual effect and cost-benefit were evaluated and compared to the standard DDT spraying technique using the Hudson X-pert sprayer. The entomological evaluation focused on mortality rates and density levels observed from intra and peridomicilliary man biting collections, indoor mosquito resting densities, curtain trap and the standard WHO wall bioassay. It was determined that when using the LV method these insecticides were highly effective. Malathion showed a residual effect of eight weeks whereas deltamethrin was found to have a residual activity of up to 12 weeks. Deltamethrin was more effective in reducing intra and peridomiciliary biting rates, and indoor resting mosquitoes. The cost-benefit ratio of deltamethrin and malathion LV house-spraying was 2.56 and 0.89, respectively, as compared to the standard DDT house-spraying. Considering its effectiveness in anopheline control and its cost-benefit, in addition to being a functional technique, intradomicile LV insecticide spraying should be considered as a practical alternative in malaria control programs.

  19. Vegetation-derived cues for the selection of oviposition substrates by Anopheles albimanus under laboratory conditions.

    PubMed

    Torres-Estrada, José Luis; Meza-Alvarez, R Amanda; Cibrián-Tovar, Juan; Rodríguez-López, Mario H; Arredondo-Jiménez, Juan I; Cruz-López, Leopoldo; Rojas-Leon, Julio C

    2005-12-01

    Oviposition response of gravid Anopheles albimanus Wiedemman (Diptera: Culicidae) females to water containing Brachiaria mutica, Cynodon dactylon, Jouvea straminea, Fimbristylis spadicea, and Ceratophyllum demersum was investigated. Gravid An. albimanus females deposited similar egg numbers in cups containing natural plants in water from natural breeding sites and in cups containing natural plants in distilled water. Gravid mosquitoes deposited significantly more eggs in cups containing natural plants in water from natural breeding sites than in cups containing artificial plants in water from the corresponding natural breeding sites. These results were confirmed in experiments conducted in a wind tunnel, indicating that female response is mediated by chemical cues from plants. Bioassays with organic extracts of all 5 plant species indicated that these extracts at 100%, 10%, and 1% concentrations had an oviposition repellent effect, while attractiveness was observed at 0.1%, 0.01%, and 0.001%. Gas chromatography and mass spectrometry analysis of the organic extracts found in all 5 plants showed a mixture of terpenoid and alcohol compounds, among them: guaiacol, phenol, isoeugenol, longifolene, caryophyllene, phenyl ethyl alcohol, and p-cresol. These results suggest that middle-range volatiles from plants may function as chemical cues for the female's oviposition response in this mosquito species.

  20. Intradomicillary pre- and postfeeding behavior of Anopheles pseudopunctipennis of southern Mexico: implications for malaria control.

    PubMed

    Casas, M; Bown, D N; Rodríguez, M H

    1994-09-01

    The intradomicillary pre- and postfeed resting behavior of Anopheles pseudopunctipennis was studied in an experimental house in southern Mexico. During resting periods (both pre-/postfeed) mosquitos had greater contact (landings) with the inner roof than with the walls and other surfaces. A comparison of mean landing frequency and overall resting time (pre-/postfeed) showed that a greater periodic and prolonged contact occurred prefeed, probably as a result of disturbed activity associated with host movements. Pre-/postfeed resting patterns on walls were limited to a 0.6-0.5-m-wide band, nearly 1 m from the floor, and to a narrower band on the roof, 0.3-0.2 m wide, approximately 2.3 m from the floor, respectively. We calculated that with a band width of 0.8 m on the walls and another band 0.8 m wide on the roof, 87.2% of the mosquitoes had at least one contact with either the wall, the roof, or with both surfaces, along with an overall mean resting time (pre-/postfeed) of 8.1 min/landing. These findings suggest that a high potential for control can be achieved by spraying preferred wall and roof resting sites in this region where the intradomicillary application of residual insecticide is the primary malaria control measure.

  1. Gonotrophic cycle and survivorship of Anopheles pseudopunctipennis (Diptera: Culicidae) in the Tapachula foothills of southern Mexico.

    PubMed

    Fernandez-Salas, I; Rodriguez, M H; Roberts, D R

    1994-05-01

    Mark-release-recapture experiments were conducted to determine the length of the gonotrophic cycle and survivorship of Anopheles pseudopunctipennis Theobald in the Tapachula foothills of southern Mexico. Separate trials with wild-caught females were conducted in the early and late dry season to examine intraseasonal differences. The gonotrophic cycle of insectary-reared, nulliparous females was estimated during the late dry season. A total of 5.4-5.7% of marked females was recaptured. A 3-d gonotrophic cycle was characteristic of wild-caught females, whereas a 4-d gonotrophic cycle was characteristic for insectary-reared females. Engorged, wild-caught females completed oogenesis in approximately 60 h under field conditions. Blood digestion in 23.5% of 2,221 and 21.9% of 1,195 engorged, wild-caught females held in the insectary was not accompanied by egg development. Dissections of these females showed that nearly 85% were nulliparous and presumably pregravid. These statistics plus other field data were used to determine that 60% of all nulliparous entered a pregravid condition. The body size and wing length of gravids was significantly larger than pregravids. Daily survival estimates of 0.875 and 0.884 were calculated for field-collected females during the early and late dry season, respectively.

  2. A test of the chromosomal theory of ecotypic speciation in Anopheles gambiae.

    PubMed

    Manoukis, Nicholas C; Powell, Jeffrey R; Touré, Mahamoudou B; Sacko, Adama; Edillo, Frances E; Coulibaly, Mamadou B; Traoré, Sekou F; Taylor, Charles E; Besansky, Nora J

    2008-02-26

    The role of chromosomal inversions in speciation has long been of interest to evolutionists. Recent quantitative modeling has stimulated reconsideration of previous conceptual models for chromosomal speciation. Anopheles gambiae, the most important vector of human malaria, carries abundant chromosomal inversion polymorphism nonrandomly associated with ecotypes that mate assortatively. Here, we consider the potential role of paracentric inversions in promoting speciation in A. gambiae via "ecotypification," a term that refers to differentiation arising from local adaptation. In particular, we focus on the Bamako form, an ecotype characterized by low inversion polymorphism and fixation of an inversion, 2Rj, that is very rare or absent in all other forms of A. gambiae. The Bamako form has a restricted distribution by the upper Niger River and its tributaries that is associated with a distinctive type of larval habitat, laterite rock pools, hypothesized to be its optimal breeding site. We first present computer simulations to investigate whether the population dynamics of A. gambiae are consistent with chromosomal speciation by ecotypification. The models are parameterized using field observations on the various forms of A. gambiae that exist in Mali, West Africa. We then report on the distribution of larvae of this species collected from rock pools and more characteristic breeding sites nearby. Both the simulations and field observations support the thesis that speciation by ecotypification is occurring, or has occurred, prompting consideration of Bamako as an independent species.

  3. Thorsellia anophelis is the dominant bacterium in a Kenyan population of adult Anopheles gambiae mosquitoes.

    PubMed

    Briones, Aurelio M; Shililu, Josephat; Githure, John; Novak, Robert; Raskin, Lutgarde

    2008-01-01

    Anopheles gambiae mosquitoes are not known to harbor endosymbiotic bacteria. Here we show, using nucleic acid-based methods, that 16S rRNA gene sequences specific to a recently described mosquito midgut bacterium, Thorsellia anophelis, is predominant in the midgut of adult An. gambiae s.l. mosquitoes captured in residences in central Kenya, and also occurs in the aquatic rice paddy environment nearby. PCR consistently detected T. anophelis in the surface microlayer of rice paddies, which is also consistent with the surface-feeding behavior of A. gambiae s.l. larvae. Phylogenetic analysis of cloned environmental 16S rRNA genes identified four major Thorsellia lineages, which are closely affiliated to an insect endosymbiont of the genus Arsenophonus. Physiological characterizations support the hypothesis that T. anophelis is well adapted to the female anopheline midgut by utilizing blood and tolerating the alkaline conditions in this environment. The results suggest that aquatically derived bacteria such as T. anophelis can persist through mosquito metamorphosis and become well-established in the adult mosquito midgut.

  4. Population genetic structure of Anopheles arabiensis (Diptera: Culicidae) in a rice growing area of central Kenya.

    PubMed

    Muturi, Ephantus J; Kim, Chang-Hyun; Baliraine, Frederick N; Musani, Solomon; Jacob, Benjamin; Githure, John; Novak, Robert J

    2010-03-01

    Studies were conducted to examine the population genetic structure of Anopheles arabiensis (Patton) in Mwea Rice Irrigation Scheme and surrounding areas in Central Kenya, under different agricultural systems. This study was motivated by observed differences in malaria transmission indices of An. arabiensis within the scheme compared with adjacent nonirrigated areas. Agricultural practices can modify local microclimate and influence the number and diversity of larval habitats and in so doing may occasion subpopulation differentiation. Thirty samples from each of the three study sites were genotyped at eight microsatellite loci. Seven microsatellite loci showed high polymorphism but revealed no genetic differentiation (FST = 0.006, P = 0.312) and high gene flow (Nm = 29-101) among the three populations. Genetic bottleneck analysis showed no indication of excess heterozygosity in any of the populations. There was high frequency of rare alleles, suggesting that An. arabiensis in the study area has a high potential of responding to selective pressures from environmental changes and vector control efforts. These findings imply that An. arabiensis in the study area occurs as a single, continuous panmictic population with great ability to adapt to human-imposed selective pressures.

  5. Plasmodium falciparum infection rates for some Anopheles spp. from Guinea-Bissau, West Africa

    PubMed Central

    Sanford, Michelle R.; Cornel, Anthony J.; Nieman, Catelyn C.; Dinis, Joao; Marsden, Clare D.; Weakley, Allison M.; Han, Sarah; Rodrigues, Amabelia; Lanzaro, Gregory C.; Lee, Yoosook

    2014-01-01

    Presence of Plasmodium falciparum circumsporozoite protein (CSP) was detected by enzyme linked immunosorbent assay (ELISA) in a sample of Anopheles gambiae s.s., A. melas and A. pharoensis collected in Guinea-Bissau during October and November 2009. The percentage of P. falciparum infected samples (10.2% overall; confidence interval (CI): 7.45-13.6%) was comparable to earlier studies from other sites in Guinea-Bissau (9.6-12.4%). The majority of the specimens collected were identified as A. gambiae which had an individual infection rate of 12.6 % (CI: 8.88-17.6) across collection sites. A small number of specimens of A. coluzzii, A. coluzzii x A. gambiae hybrids, A. melas and A. pharoensis were collected and had infection rates of 4.3% (CI:0.98-12.4), 4.1% (CI:0.35-14.5), 11.1% (CI:1.86-34.1) and 33.3% (CI:9.25-70.4) respectively. Despite being present in low numbers in indoor collections, the exophilic feeding behaviors of A. melas (N=18) and A. pharoensis (N=6) and high infection rates observed in this survey suggest falciparum-malaria transmission potential outside of the protection of bed nets. PMID:25383188

  6. Carbamate and Pyrethroid Resistance in the Akron Strain of Anopheles gambiae

    PubMed Central

    Mutunga, James M.; Anderson, Troy D.; Craft, Derek T.; Gross, Aaron D.; Swale, Daniel R.; Tong, Fan; Wong, Dawn M.; Carlier, Paul R.; Bloomquist, Jeffrey R.

    2015-01-01

    Insecticide resistance in the malaria vector, Anopheles gambiae is a serious problem, epitomized by the multi-resistant Akron strain, originally isolated in the country of Benin. Here we report resistance in this strain to pyrethroids and DDT (13-fold to 35-fold compared to the susceptible G3 strain), but surprisingly little resistance to etofenprox, a compound sometimes described as a “pseudo-pyrethroid.” There was also strong resistance to topically-applied commercial carbamates (45-fold to 81-fold), except for the oximes aldicarb and methomyl. Biochemical assays showed enhanced cytochrome P450 monooxygenase and carboxylesterase activity, but not that of glutathione-S-transferase. A series of substituted α,α,α,-trifluoroacetophenone oxime methylcarbamates were evaluated for enzyme inhibition potency and toxicity against G3 and Akron mosquitoes. The compound bearing an unsubstituted phenyl ring showed the greatest toxicity to mosquitoes of both strains. Low cross resistance in Akron was retained by all analogs in the series. Kinetic analysis of acetylcholinesterase activity and its inhibition by insecticides in the G3 strain showed inactivation rate constants greater than that of propoxur, and against Akron enzyme inactivation rate constants similar to that of aldicarb. However, inactivation rate constants against recombinant human AChE were essentially identical to that of the G3 strain. Thus, the acetophenone oxime carbamates described here, though potent insecticides that control resistant Akron mosquitoes, require further structural modification to attain acceptable selectivity and human safety. PMID:26047119

  7. Suboptimal Larval Habitats Modulate Oviposition of the Malaria Vector Mosquito Anopheles coluzzii

    PubMed Central

    Suh, Eunho; Choe, Dong-Hwan; Saveer, Ahmed M.; Zwiebel, Laurence J.

    2016-01-01

    Selection of oviposition sites by gravid females is a critical behavioral step in the reproductive cycle of Anopheles coluzzii, which is one of the principal Afrotropical malaria vector mosquitoes. Several studies suggest this decision is mediated by semiochemicals associated with potential oviposition sites. To better understand the chemosensory basis of this behavior and identify compounds that can modulate oviposition, we examined the generally held hypothesis that suboptimal larval habitats give rise to semiochemicals that negatively influence the oviposition preference of gravid females. Dual-choice bioassays indicated that oviposition sites conditioned in this manner do indeed foster significant and concentration dependent aversive effects on the oviposition site selection of gravid females. Headspace analyses derived from aversive habitats consistently noted the presence of dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS) and 6-methyl-5-hepten-2-one (sulcatone) each of which unitarily affected An. coluzzii oviposition preference. Electrophysiological assays across the antennae, maxillary palp, and labellum of gravid An. coluzzii revealed differential responses to these semiochemicals. Taken together, these findings validate the hypothesis in question and suggest that suboptimal environments for An. coluzzii larval development results in the release of DMDS, DMTS and sulcatone that impact the response valence of gravid females. PMID:26900947

  8. Interactive cost of Plasmodium infection and insecticide resistance in the malaria vector Anopheles gambiae

    PubMed Central

    Alout, Haoues; Dabiré, Roch K.; Djogbénou, Luc S.; Abate, Luc; Corbel, Vincent; Chandre, Fabrice; Cohuet, Anna

    2016-01-01

    Insecticide resistance raises concerns for the control of vector-borne diseases. However, its impact on parasite transmission could be diverse when considering the ecological interactions between vector and parasite. Thus we investigated the fitness cost associated with insecticide resistance and Plasmodium falciparum infection as well as their interactive cost on Anopheles gambiae survival and fecundity. In absence of infection, we observed a cost on fecundity associated with insecticide resistance. However, survival was higher for mosquito bearing the kdr mutation and equal for those with the ace-1R mutation compared to their insecticide susceptible counterparts. Interestingly, Plasmodium infection reduced survival only in the insecticide resistant strains but not in the susceptible one and infection was associated with an increase in fecundity independently of the strain considered. This study provides evidence for a survival cost associated with infection by Plasmodium parasite only in mosquito selected for insecticide resistance. This suggests that the selection of insecticide resistance mutation may have disturbed the interaction between parasites and vectors, resulting in increased cost of infection. Considering the fitness cost as well as other ecological aspects of this natural mosquito-parasite combination is important to predict the epidemiological impact of insecticide resistance. PMID:27432257

  9. Midgut Microbiota of the Malaria Mosquito Vector Anopheles gambiae and Interactions with Plasmodium falciparum Infection

    PubMed Central

    Boissière, Anne; Tchioffo, Majoline T.; Bachar, Dipankar; Abate, Luc; Marie, Alexandra; Nsango, Sandrine E.; Shahbazkia, Hamid R.; Awono-Ambene, Parfait H.; Levashina, Elena A.; Christen, Richard; Morlais, Isabelle

    2012-01-01

    The susceptibility of Anopheles mosquitoes to Plasmodium infections relies on complex interactions between the insect vector and the malaria parasite. A number of studies have shown that the mosquito innate immune responses play an important role in controlling the malaria infection and that the strength of parasite clearance is under genetic control, but little is known about the influence of environmental factors on the transmission success. We present here evidence that the composition of the vector gut microbiota is one of the major components that determine the outcome of mosquito infections. A. gambiae mosquitoes collected in natural breeding sites from Cameroon were experimentally challenged with a wild P. falciparum isolate, and their gut bacterial content was submitted for pyrosequencing analysis. The meta-taxogenomic approach revealed a broader richness of the midgut bacterial flora than previously described. Unexpectedly, the majority of bacterial species were found in only a small proportion of mosquitoes, and only 20 genera were shared by 80% of individuals. We show that observed differences in gut bacterial flora of adult mosquitoes is a result of breeding in distinct sites, suggesting that the native aquatic source where larvae were grown determines the composition of the midgut microbiota. Importantly, the abundance of Enterobacteriaceae in the mosquito midgut correlates significantly with the Plasmodium infection status. This striking relationship highlights the role of natural gut environment in parasite transmission. Deciphering microbe-pathogen interactions offers new perspectives to control disease transmission. PMID:22693451

  10. Modulation of Malaria Infection in Anopheles gambiae Mosquitoes Exposed to Natural Midgut Bacteria

    PubMed Central

    Tchioffo, Majoline T.; Boissière, Anne; Churcher, Thomas S.; Abate, Luc; Gimonneau, Geoffrey; Nsango, Sandrine E.; Awono-Ambéné, Parfait H.; Christen, Richard; Berry, Antoine; Morlais, Isabelle

    2013-01-01

    The development of Plasmodium falciparum within the Anopheles gambiae mosquito relies on complex vector-parasite interactions, however the resident midgut microbiota also plays an important role in mediating parasite infection. In natural conditions, the mosquito microbial flora is diverse, composed of commensal and symbiotic bacteria. We report here the isolation of culturable midgut bacteria from mosquitoes collected in the field in Cameroon and their identification based on the 16S rRNA gene sequencing. We next measured the effect of selected natural bacterial isolates on Plasmodium falciparum infection prevalence and intensity over multiple infectious feedings and found that the bacteria significantly reduced the prevalence and intensity of infection. These results contrast with our previous study where the abundance of Enterobacteriaceae positively correlated with P. falciparum infection (Boissière et al. 2012). The oral infection of bacteria probably led to the disruption of the gut homeostasis and activated immune responses, and this pinpoints the importance of studying microbe-parasite interactions in natural conditions. Our results indicate that the effect of bacterial exposure on P. falciparum infection varies with factors from the parasite and the human host and calls for deeper dissection of these parameters for accurate interpretation of bacterial exposure results in laboratory settings. PMID:24324714

  11. Dynamic Gut Microbiome across Life History of the Malaria Mosquito Anopheles gambiae in Kenya

    PubMed Central

    Kukutla, Phanidhar; Yan, Guiyun; Xu, Jiannong

    2011-01-01

    The mosquito gut represents an ecosystem that accommodates a complex, intimately associated microbiome. It is increasingly clear that the gut microbiome influences a wide variety of host traits, such as fitness and immunity. Understanding the microbial community structure and its dynamics across mosquito life is a prerequisite for comprehending the symbiotic relationship between the mosquito and its gut microbial residents. Here we characterized gut bacterial communities across larvae, pupae and adults of Anopheles gambiae reared in semi-natural habitats in Kenya by pyrosequencing bacterial 16S rRNA fragments. Immatures and adults showed distinctive gut community structures. Photosynthetic Cyanobacteria were predominant in the larval and pupal guts while Proteobacteria and Bacteroidetes dominated the adult guts, with core taxa of Enterobacteriaceae and Flavobacteriaceae. At the adult stage, diet regime (sugar meal and blood meal) significantly affects the microbial structure. Intriguingly, blood meals drastically reduced the community diversity and favored enteric bacteria. Comparative genomic analysis revealed that the enriched enteric bacteria possess large genetic redox capacity of coping with oxidative and nitrosative stresses that are associated with the catabolism of blood meal, suggesting a beneficial role in maintaining gut redox homeostasis. Interestingly, gut community structure was similar in the adult stage between the field and laboratory mosquitoes, indicating that mosquito gut is a selective eco-environment for its microbiome. This comprehensive gut metatgenomic profile suggests a concerted symbiotic genetic association between gut inhabitants and host. PMID:21957459

  12. Insights from the Genome Annotation of Elizabethkingia anophelis from the Malaria Vector Anopheles gambiae

    PubMed Central

    Pei, Dong; Rayl, Melanie; Yu, Wanqin; Steritz, Matthew; Faye, Ingrid; Xu, Jiannong

    2014-01-01

    Elizabethkingia anophelis is a dominant bacterial species in the gut ecosystem of the malaria vector mosquito Anopheles gambiae. We recently sequenced the genomes of two strains of E. anophelis, R26T and Ag1, isolated from different strains of A. gambiae. The two bacterial strains are identical with a few exceptions. Phylogenetically, Elizabethkingia is closer to Chryseobacterium and Riemerella than to Flavobacterium. In line with other Bacteroidetes known to utilize various polymers in their ecological niches, the E. anophelis genome contains numerous TonB dependent transporters with various substrate specificities. In addition, several genes belonging to the polysaccharide utilization system and the glycoside hydrolase family were identified that could potentially be of benefit for the mosquito carbohydrate metabolism. In agreement with previous reports of broad antibiotic resistance in E. anophelis, a large number of genes encoding efflux pumps and β-lactamases are present in the genome. The component genes of resistance-nodulation-division type efflux pumps were found to be syntenic and conserved in different taxa of Bacteroidetes. The bacterium also displays hemolytic activity and encodes several hemolysins that may participate in the digestion of erythrocytes in the mosquito gut. At the same time, the OxyR regulon and antioxidant genes could provide defense against the oxidative stress that is associated with blood digestion. The genome annotation and comparative genomic analysis revealed functional characteristics associated with the symbiotic relationship with the mosquito host. PMID:24842809

  13. Insights from the genome annotation of Elizabethkingia anophelis from the malaria vector Anopheles gambiae.

    PubMed

    Kukutla, Phanidhar; Lindberg, Bo G; Pei, Dong; Rayl, Melanie; Yu, Wanqin; Steritz, Matthew; Faye, Ingrid; Xu, Jiannong

    2014-01-01

    Elizabethkingia anophelis is a dominant bacterial species in the gut ecosystem of the malaria vector mosquito Anopheles gambiae. We recently sequenced the genomes of two strains of E. anophelis, R26T and Ag1, isolated from different strains of A. gambiae. The two bacterial strains are identical with a few exceptions. Phylogenetically, Elizabethkingia is closer to Chryseobacterium and Riemerella than to Flavobacterium. In line with other Bacteroidetes known to utilize various polymers in their ecological niches, the E. anophelis genome contains numerous TonB dependent transporters with various substrate specificities. In addition, several genes belonging to the polysaccharide utilization system and the glycoside hydrolase family were identified that could potentially be of benefit for the mosquito carbohydrate metabolism. In agreement with previous reports of broad antibiotic resistance in E. anophelis, a large number of genes encoding efflux pumps and β-lactamases are present in the genome. The component genes of resistance-nodulation-division type efflux pumps were found to be syntenic and conserved in different taxa of Bacteroidetes. The bacterium also displays hemolytic activity and encodes several hemolysins that may participate in the digestion of erythrocytes in the mosquito gut. At the same time, the OxyR regulon and antioxidant genes could provide defense against the oxidative stress that is associated with blood digestion. The genome annotation and comparative genomic analysis revealed functional characteristics associated with the symbiotic relationship with the mosquito host.

  14. Suboptimal Larval Habitats Modulate Oviposition of the Malaria Vector Mosquito Anopheles coluzzii.

    PubMed

    Suh, Eunho; Choe, Dong-Hwan; Saveer, Ahmed M; Zwiebel, Laurence J

    2016-01-01

    Selection of oviposition sites by gravid females is a critical behavioral step in the reproductive cycle of Anopheles coluzzii, which is one of the principal Afrotropical malaria vector mosquitoes. Several studies suggest this decision is mediated by semiochemicals associated with potential oviposition sites. To better understand the chemosensory basis of this behavior and identify compounds that can modulate oviposition, we examined the generally held hypothesis that suboptimal larval habitats give rise to semiochemicals that negatively influence the oviposition preference of gravid females. Dual-choice bioassays indicated that oviposition sites conditioned in this manner do indeed foster significant and concentration dependent aversive effects on the oviposition site selection of gravid females. Headspace analyses derived from aversive habitats consistently noted the presence of dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS) and 6-methyl-5-hepten-2-one (sulcatone) each of which unitarily affected An. coluzzii oviposition preference. Electrophysiological assays across the antennae, maxillary palp, and labellum of gravid An. coluzzii revealed differential responses to these semiochemicals. Taken together, these findings validate the hypothesis in question and suggest that suboptimal environments for An. coluzzii larval development results in the release of DMDS, DMTS and sulcatone that impact the response valence of gravid females.

  15. Oviposition site preference and egg hatchability of Anopheles gambiae: effects of land cover types.

    PubMed

    Munga, Stephen; Minakawa, Noboru; Zhou, Guofa; Barrack, Okeyo-Owuor J; Githeko, Andrew K; Yan, Guiyun

    2005-11-01

    We studied the oviposition site preference and egg hatchability of Anopheles gambiae Giles with water collected from farmlands, forests, and natural wetlands. Water types significantly affected oviposition preference. Mosquitoes deposited significantly more eggs in rainwater in both the dry and wet seasons than waters from forests and wetlands, suggesting that An. gambiae prefers water with few impurities for oviposition. In the dry season, An. gambiae females also deposited significantly more eggs in waters from farmlands than those from forests and natural wetlands, but these differences were not statistically significant during the wet season. In both indoor and natural conditions, egg mortality in natural wetland habitats was significantly higher than in farmland habitats. The average water temperature in natural wetland habitats was significantly lower than farmland habitats in the natural conditions, but it remained the same under indoor experimental conditions, suggesting that factors other than water temperature play an important role in egg hatchability. Together with the findings from previous studies on the effects of land cover on larval survivorship, our results support the hypothesis that variations in habitat conditions induced by different land cover types contribute to the heterogeneous spatial distribution of An. gambiae larvae in the western Kenya highland.

  16. Anopheles culicifacies: siblings species composition and its relationship to malaria incidence.

    PubMed

    Subbarao, S K; Vasantha, K; Raghavendra, K; Sharma, V P; Sharma, G K

    1988-03-01

    Entomological and epidemiological surveys in May, August and November 1985 and March 1986 were conducted in villages in Bulandshahr, a western district in Uttar Pradesh and in three eastern districts, Jaunpur, Ballia and Saran. In Bulandshahr, Anopheles culicifacies sibling species A and B were found, with a predominance of species A. Both Plasmodium vivax and P. falciparum were present and the malaria incidence remained high (SPR, 6-50%) indicating an active transmission. In contrast, in three eastern districts predominance of species B with an occasional occurrence of species A was observed. Malaria cases were almost absent in Ballia and Saran and in Jaunpur 10.3% slide positivity rate was observed in May but in later surveys cases were considerably lower (SPR, 0.5-2.9%) indicating the absence of indigenous transmission. In the eastern districts, malaria parasites are regularly brought in from endemic areas by the migrant labor population. Although An. culicifacies s.l. occurs in both the areas, the difference in malaria incidence appears to be due to the difference in the composition of the sibling species which is, the predominant presence of species A in the western district and its absence in eastern districts. This indicates that species A is responsible for active malaria transmission while species B is not.

  17. Variant Ionotropic Receptors in the Malaria Vector Mosquito Anopheles gambiae Tuned to Amines and Carboxylic Acids

    PubMed Central

    Pitts, R. Jason; Derryberry, Stephen L.; Zhang, Zhiwei; Zwiebel, Laurence J.

    2017-01-01

    The principal Afrotropical human malaria vector mosquito, Anopheles gambiae, remains a significant threat to global health. A critical component in the transmission of malaria is the ability of An. gambiae females to detect and respond to human-derived chemical kairomones in their search for blood meal hosts. The basis for host odor responses resides in olfactory receptor neurons (ORNs) that express chemoreceptors encoded by large gene families, including the odorant receptors (ORs) and the variant ionotropic receptors (IRs). While ORs have been the focus of extensive investigation, functional IR complexes and the chemical compounds that activate them have not been identified in An. gambiae. Here we report the transcriptional profiles and functional characterization of three An. gambiae IR (AgIr) complexes that specifically respond to amines or carboxylic acids - two classes of semiochemicals that have been implicated in mediating host-seeking by adult females but are not known to activate An. gambiae ORs (AgOrs). Our results suggest that AgIrs play critical roles in the detection and behavioral responses to important classes of host odors that are underrepresented in the AgOr chemical space. PMID:28067294

  18. Brazilian Anopheles darlingi Root (Diptera: Culicidae) Clusters by Major Biogeographical Region

    PubMed Central

    Bergo, Eduardo S.; Randel, Melissa A.

    2015-01-01

    The major drivers of the extensive biodiversity of the Neotropics are proposed to be geological and tectonic events together with Pliocene and Pleistocene environmental and climatic change. Geographical barriers represented by the rivers Amazonas/Solimões, the Andes and the coastal mountain ranges in eastern Brazil have been hypothesized to lead to diversification within the primary malaria vector, Anopheles (Nyssorhynchus) darlingi Root, which primarily inhabits rainforest. To test this biogeographical hypothesis, we analyzed 786 single nucleotide polymorphisms (SNPs) in 12 populations of An. darlingi from across the complex Brazilian landscape. Both model-based (STRUCTURE) and non-model-based (Principal Components and Discriminant Analysis) analysis of population structure detected three major genetic clusters that correspond with newly described Neotropical biogeographical regions: 1) Atlantic Forest province (= southeast population); 2) Parana Forest province (= West Atlantic forest population, with one Chacoan population - SP); and 3) Brazilian dominion population (= Amazonian population with one Chacoan population - TO). Significant levels of pairwise genetic divergences were found among the three clusters, allele sharing among clusters was negligible, and geographical distance did not contribute to differentiation. We infer that the Atlantic forest coastal mountain range limited dispersal between the Atlantic Forest province and the Parana Forest province populations, and that the large, diagonal open vegetation region of the Chacoan dominion dramatically reduced dispersal between the Parana and Brazilian dominion populations. We hypothesize that the three genetic clusters may represent three putative species. PMID:26172559

  19. CPF and CPFL, two related gene families encoding cuticular proteins of Anopheles gambiae and other insects.

    PubMed

    Togawa, Toru; Augustine Dunn, W; Emmons, Aaron C; Willis, Judith H

    2007-07-01

    Cuticular proteins (CPs) are structural proteins of insects as well as other arthropods. Several CP families have been described, among them a small family defined by a 51 amino acid motif [Andersen, S.O., Rafn, K., Roepstorff, P., 1997. Sequence studies of proteins from larval and pupal cuticle of the yellow meal worm, Tenebrio molitor. Insect Biochem. Mol. Biol. 27, 121-131]. We identified four proteins of this family in Anopheles gambiae that we have named CPF. We have also identified CPFs from other insects by searching databases. Alignment of these CPF proteins showed that the conserved region is only 44 aa long and revealed another conserved motif at the C-terminus. A dendrogram divided the CPF proteins into four groups, one basal and three specialized. We also identified several proteins of another CP family, CPFL, which has similarities to CPFs. CPFs and CPFLs share some protein motifs. Expression studies with real-time qRT-PCR of the A. gambiae CPFs and CPFLs showed that the four CPFs and one CPFL gene are expressed just before pupal or adult ecdysis, suggesting that they are components of the outer layer of pupal and adult cuticles. The other CPFLs appear to contribute to larval cuticle. Recombinant CPF proteins did not bind to chitin in the assay we used.

  20. Larval density dependence in Anopheles gambiae s.s., the major African vector of malaria.

    PubMed

    Muriu, Simon M; Coulson, Tim; Mbogo, Charles M; Godfray, H Charles J

    2013-01-01

    Anopheles gambiae sensu stricto is the most important vector of malaria in Africa although relatively little is known about the density-dependent processes determining its population size. Mosquito larval density was manipulated under semi-natural conditions using artificial larval breeding sites placed in the field in coastal Kenya; two experiments were conducted: one manipulating the density of a single cohort of larvae across a range of densities and the other employing fewer densities but with the treatments crossed with four treatments manipulating predator access. In the first experiment, larval survival, development rate and the size of the adult mosquito all decreased with larval density (controlling for block effects between 23% and 31% of the variance in the data could be explained by density). In the second experiment, the effects of predator manipulation were not significant, but again we observed strong density dependence in larval survival (explaining 30% of the variance). The results are compared with laboratory studies of A. gambiae larval competition and the few other studies conducted in the field, and the consequences for malaria control are discussed.

  1. Molecular Characterization of Larval Peripheral Thermosensory Responses of the Malaria Vector Mosquito Anopheles gambiae

    PubMed Central

    Liu, Chao; Zwiebel, Laurence J.

    2013-01-01

    Thermosensation provides vital inputs for the malaria vector mosquito, Anopheles gambiae which utilizes heat-sensitivity within a broad spectrum of behaviors, most notably, the localization of human hosts for blood feeding. In this study, we examine thermosensory behaviors in larval-stage An. gambiae, which as a result of their obligate aquatic habitats and importance for vectorial capacity, represents an opportunistic target for vector control as part of the global campaign to eliminate malaria. As is the case for adults, immature mosquitoes respond differentially to a diverse array of external heat stimuli. In addition, larvae exhibit a striking phenotypic plasticity in thermal-driven behaviors that are established by temperature at which embryonic development occurs. Within this spectrum, RNAi-directed gene-silencing studies provide evidence for the essential role of the Transient Receptor Potential sub-family A1 (TRPA1) channel in mediating larval thermal-induced locomotion and thermal preference within a discrete upper range of ambient temperatures. PMID:23940815

  2. Three-dimensional structures of the tracheal systems of Anopheles sinensis and Aedes togoi pupae

    PubMed Central

    Ha, Young-Ran; Yeom, Eunseop; Ryu, Jeongeun; Lee, Sang-Joon

    2017-01-01

    Mosquitoes act as a vector for the transmission of disease. The World Health Organization has recommended strict control of mosquito larvae because of their “few, fixed, and findable” features. The respiratory system of mosquito larvae and pupae in the water has a weak point. As aquatic organisms, mosquito larvae and pupae inhale atmosphere oxygen. However, the mosquito pupae have a non-feeding stage, unlike the larvae. Therefore, detailed study on the tracheal system of mosquito pupae is helpful for understanding their survival strategy. In this study, the three-dimensional (3D) structures of the tracheal systems of Anopheles sinensis and Aedes togoi pupae were comparatively investigated using synchrotron X-ray microscopic computed tomography. The respiratory frequencies of the dorsal trunks were also investigated. Interestingly, the pupae of the two mosquito species possess special tracheal systems of which the morphological and functional features are distinctively different. The respiratory frequency of Ae. togoi is higher than that of An. sinensis. These differences in the breathing phenomena and 3D structures of the respiratory systems of these two mosquito species provide an insight into the tracheal systems of mosquito pupae. PMID:28287649

  3. Impact of trehalose transporter knockdown on Anopheles gambiae stress adaptation and susceptibility to Plasmodium falciparum infection

    PubMed Central

    Liu, Kun; Dong, Yuemei; Huang, Yuzheng; Rasgon, Jason L.; Agre, Peter

    2013-01-01

    Anopheles gambiae is a major vector mosquito for Plasmodium falciparum, the deadly pathogen causing most human malaria in sub-Saharan Africa. Synthesized in the fat body, trehalose is the predominant sugar in mosquito hemolymph. It not only provides energy but also protects the mosquito against desiccation and heat stresses. Trehalose enters the mosquito hemolymph by the trehalose transporter AgTreT1. In adult female A. gambiae, AgTreT1 is predominantly expressed in the fat body. We found that AgTreT1 expression is induced by environmental stresses such as low humidity or elevated temperature. AgTreT1 RNA silencing reduces the hemolymph trehalose concentration by 40%, and the mosquitoes succumb sooner after exposure to desiccation or heat. After an infectious blood meal, AgTreT1 RNA silencing reduces the number of P. falciparum oocysts in the mosquito midgut by over 70% compared with mock-injected mosquitoes. These data reveal important roles for AgTreT1 in stress adaptation and malaria pathogen development in a major vector mosquito. Thus, AgTreT1 may be a potential target for malaria vector control. PMID:24101462

  4. Screening of selected ethnomedicinal plants from South Africa for larvicidal activity against the mosquito Anopheles arabiensis

    PubMed Central

    2012-01-01

    Background This study was initiated to establish whether any South African ethnomedicinal plants (indigenous or exotic), that have been reported to be used traditionally to repel or kill mosquitoes, exhibit effective mosquito larvicidal properties. Methods Extracts of a selection of plant taxa sourced in South Africa were tested for larvicidal properties in an applicable assay. Thirty 3rd instar Anopheles arabiensis larvae were exposed to various extract types (dichloromethane, dichloromethane/methanol) (1:1), methanol and purified water) of each species investigated. Mortality was evaluated relative to the positive control Temephos (Mostop; Agrivo), an effective emulsifiable concentrate larvicide. Results Preliminary screening of crude extracts revealed substantial variation in toxicity with 24 of the 381 samples displaying 100% larval mortality within the seven day exposure period. Four of the high activity plants were selected and subjected to bioassay guided fractionation. The results of the testing of the fractions generated identified one fraction of the plant, Toddalia asiatica as being very potent against the An. arabiensis larvae. Conclusion The present study has successfully identified a plant with superior larvicidal activity at both the crude and semi pure fractions generated through bio-assay guided fractionation. These results have initiated further research into isolating the active compound and developing a malaria vector control tool. PMID:22963538

  5. Rhodopsin coexpression in UV photoreceptors of Aedes aegypti and Anopheles gambiae mosquitoes.

    PubMed

    Hu, Xiaobang; Leming, Matthew T; Whaley, Michelle A; O'Tousa, Joseph E

    2014-03-15

    Differential rhodopsin gene expression within specialized R7 photoreceptor cells divides the retinas of Aedes aegypti and Anopheles gambiae mosquitoes into distinct domains. The two species express the rhodopsin orthologs Aaop8 and Agop8, respectively, in a large subset of these R7 photoreceptors that function as ultraviolet receptors. We show here that a divergent subfamily of mosquito rhodopsins, Aaop10 and Agop10, is coexpressed in these R7 photoreceptors. The properties of the A. aegypti Aaop8 and Aaop10 rhodopsins were analyzed by creating transgenic Drosophila expressing these rhodopsins. Electroretinogram recordings, and spectral analysis of head extracts, obtained from the Aaop8 strain confirmed that Aaop8 is an ultraviolet-sensitive rhodopsin. Aaop10 was poorly expressed and capable of eliciting only small and slow light responses in Drosophila photoreceptors, and electroretinogram analysis suggested that it is a long-wavelength rhodopsin with a maximal sensitivity near 500 nm. Thus, coexpression of Aaop10 rhodopsin with Aaop8 rhodopsin has the potential to modify the spectral properties of mosquito ultraviolet receptors. Retention of Op10 rhodopsin family members in the genomes of Drosophila species suggests that this rhodopsin family may play a conserved role in insect vision.

  6. Essential oils enhance the toxicity of permethrin against Aedes aegypti and Anopheles gambiae.

    PubMed

    Gross, A D; Norris, E J; Kimber, M J; Bartholomay, L C; Coats, J R

    2017-03-01

    Insecticide resistance and growing public concern over the safety and environmental impacts of some conventional insecticides have resulted in the need to discover alternative control tools. Naturally occurring botanically-based compounds are of increased interest to aid in the management of mosquitoes. Susceptible strains of Aedes aegypti (Linnaeus) (Diptera: Culicidae) and Anopheles gambiae (Meigen) (Diptera: Culicidae) were treated with permethrin, a common type-I synthetic pyrethroid, using a discriminate dose that resulted in less than 50% mortality. Piperonyl butoxide (PBO) and 35 essential oils were co-delivered with permethrin at two doses (2 and 10 µg) to determine if they could enhance the 1-h knockdown and the 24-h mortality of permethrin. Several of the tested essential oils enhanced the efficacy of permethrin equally and more effectively than piperonyl butoxide PBO, which is the commercial standard to synergize chemical insecticide like pyrethroids. PBO had a strikingly negative effect on the 1-h knockdown of permethrin against Ae. aegypti, which was not observed in An. gambiae. Botanical essential oils have the capability of increasing the efficacy of permethrin allowing for a natural alternative to classic chemical synergists, like PBO.

  7. Some ecological attributes of malarial vector Anopheles superpictus Grassi in endemic foci in southeastern Iran

    PubMed Central

    Nejati, Jalil; Vatandoost, Hasan; Oshghi, Mohammad Ali; Salehi, Masud; Mozafari, Ehssan; Moosa-Kazemi, Seyed Hasan

    2013-01-01

    Objective To determine the bionomics and susceptibility status of the malarial vector Anopheles superpictus (An. superpictus) to different insecticides in the Sistan-Baluchestan province which has the highest malarial prevalence in Iran. Methods Different sampling methods, in addition to scoring abdominal conditions, were used to define the seasonal activity and endo/exophilic behavior of this species. In addition, the standard WHO susceptibility tests were applied on adult field strains. Results Most adult mosquitoes were collected from outdoor shelters. The peak of seasonal activity of An. superpictus occurred at the end of autumn. Most larvae were collected from natural and permanent breeding places with full sunlight and no vegetation. Blood feeding activities occurred around midnight. Compared with the abdominal conditions of adult mosquitoes collected indoors, the abdominal conditions of adult mosquitoes collected outdoors were gravid and semigravid. This species was suspected to be resistant to DDT, but was susceptible to other insecticides. Conclusions An. superpictus was present in almost all outdoor shelters, and the ratios of gravid, semigravid/unfed, and freshly fed confirmed that this species had a higher tendency to rest outdoors than indoors. This behavior can protect An. superpictus from indoor residual spraying in this malarious area. To the best of our knowledge, this is the first report on the susceptibility status of An. superpictus in Southeastern Iran. We do not suggest the use of DDT for indoor residual spraying in southeast Iran. PMID:24093794

  8. Stable chromosomal inversion polymorphisms and insecticide resistance in the malaria vector mosquito Anopheles gambiae (Diptera: Culicidae).

    PubMed

    Brooke, B D; Hunt, R H; Chandre, F; Carnevale, P; Coetzee, M

    2002-07-01

    Anopheles gambiae Giles has been implicated as a major vector of malaria in Africa. A number of paracentric chromosomal inversions have been observed as polymorphisms in wild and laboratory populations of this species. These polymorphisms have been used to demonstrate the existence of five reproductive units in West African populations that are currently described as incipient species. They have also been correlated with various behavioral characteristics such as adaptation to aridity and feeding preference and have been associated with insecticide resistance. Two paracentric inversions namely 2La and 2Rb are highly ubiquitous in the wild and laboratory populations sampled. Both inversions are easily conserved during laboratory colonization of wild material and one shows significant positive heterosis with respect to Hardy-Weinberg proportions. Inversion 2La has previously been associated with dieldrin resistance and inversion 2Rb shows an association with DDT resistance based on this study. The stability and maintenance of these inversions as polymorphisms provides an explanation for the transmission and continued presence of DDT and dieldrin resistance in a laboratory strain of An. gambiae in the absence of insecticide selection pressure. This effect may also be operational in wild populations. Stable inversion polymorphism also provides a possible mechanism for the continual inheritance of suitable genetic factors that otherwise compromise the fitness of genetically modified malaria vector mosquitoes.

  9. Relationship between knockdown resistance, metabolic detoxification and organismal resistance to pyrethroids in Anopheles sinensis.

    PubMed

    Zhong, Daibin; Chang, Xuelian; Zhou, Guofa; He, Zhengbo; Fu, Fengyang; Yan, Zhentian; Zhu, Guoding; Xu, Tielong; Bonizzoni, Mariangela; Wang, Mei-Hui; Cui, Liwang; Zheng, Bin; Chen, Bin; Yan, Guiyun

    2013-01-01

    Anopheles sinensis is the most important vector of malaria in Southeast Asia, including China. Currently, the most effective measure to prevent malaria transmission relies on vector control through the use of insecticides, primarily pyrethroids. Extensive use of insecticides poses strong selection pressure on mosquito populations for resistance. Resistance to insecticides can arise due to mutations in the insecticide target site (target site resistance), which in the case of pyrethroids is the para-type sodium channel gene, and/or the catabolism of the insecticide by detoxification enzymes before it reaches its target (metabolic detoxification resistance). In this study, we examined deltamethrin resistance in An. sinensis from China and investigated the relative importance of target site versus metabolic detoxification mechanisms in resistance. A high frequency (>85%) of nonsynonymous mutations in the para gene was found in populations from central China, but not in populations from southern China. Metabolic detoxification as measured by the activity of monooxygenases and glutathione S-transferases (GSTs) was detected in populations from both central and southern China. Monooxygenase activity levels were significantly higher in the resistant than the susceptible mosquitoes, independently of their geographic origin. Stepwise multiple regression analyses in mosquito populations from central China found that both knockdown resistance (kdr) mutations and monooxygenase activity were significantly associated with deltamethrin resistance, with monooxygenase activity playing a stronger role. These results demonstrate the importance of metabolic detoxification in pyrethroid resistance in An. sinensis, and suggest that different mechanisms of resistance could evolve in geographically different populations.

  10. Human blood-feeding rates among sympatric sibling species of Anopheles quadrimaculatus mosquitoes in northern Florida.

    PubMed

    Jensen, T; Cockburn, A F; Kaiser, P E; Barnard, D R

    1996-05-01

    We compared rates of feeding on human hosts for blood-engorged female Anopheles quadrimaculatus species A, B and C1 collected from daytime resting sites in Manatee Springs State Park, Levy County, Florida during 1992-1993. Quick-blot DNA probes were used to identify mosquito taxa and also the presence of human blood in the mosquito gut. In collections from a campground area, human blood-feeding rates differed significantly among mosquito species (10.7% [19 of 177], 0%, [0 of 62], and 1.2%, [4 of 327]), respectively for species A, B and C1). In collections from a woodland site (1 km from the campground), 1.5% (2 of 129) of the species B females had fed on humans, whereas none of 19 species A or 159 species C1 females had done so. Of the three species in this study area, species A appears the most likely to be a biting pest of humans and a vector of human malaria.

  11. Genetic Structure of a Local Population of the Anopheles gambiae Complex in Burkina Faso

    PubMed Central

    Markianos, Kyriacos; Bischoff, Emmanuel; Mitri, Christian; Guelbeogo, Wamdaogo M.; Gneme, Awa; Eiglmeier, Karin; Holm, Inge; Sagnon, N’Fale; Vernick, Kenneth D.; Riehle, Michelle M.

    2016-01-01

    Members of the Anopheles gambiae species complex are primary vectors of human malaria in Africa. Population heterogeneities for ecological and behavioral attributes expand and stabilize malaria transmission over space and time, and populations may change in response to vector control, urbanization and other factors. There is a need for approaches to comprehensively describe the structure and characteristics of a sympatric local mosquito population, because incomplete knowledge of vector population composition may hinder control efforts. To this end, we used a genome-wide custom SNP typing array to analyze a population collection from a single geographic region in West Africa. The combination of sample depth (n = 456) and marker density (n = 1536) unambiguously resolved population subgroups, which were also compared for their relative susceptibility to natural genotypes of Plasmodium falciparum malaria. The population subgroups display fluctuating patterns of differentiation or sharing across the genome. Analysis of linkage disequilibrium identified 19 new candidate genes for association with underlying population divergence between sister taxa, A. coluzzii (M-form) and A. gambiae (S-form). PMID:26731649

  12. Ecophysiology of Anopheles gambiae s.l.: Persistence in the Sahel

    PubMed Central

    Huestis, Diana L.; Lehmann, Tovi

    2014-01-01

    The dry-season biology of malaria vectors is poorly understood, especially in arid environments when no surface waters are available for several months, such as during the dry season in the Sahel. Here we reappraise results on the dry-season physiology of members of the Anopheles gambiae s.l. complex in the broad context of dormancy in insects and especially in mosquitoes. We examine evidence on seasonal changes in reproduction, metabolism, stress tolerance, nutrition, molecular regulation, and environmental conditions and determine if the current results are compatible with dry-season diapause (aestivation) as the primary strategy for persistence throughout the dry season in the Sahel. In the process, we point out critical gaps in our knowledge that future studies can fill. We find compelling evidence that members of the An. gambiae s.l. complex undergo a form of aestivation during the Sahelian dry season by shifting energetic resources away from reproduction and towards increased longevity. Considering the differences between winter at temperate latitudes, which entails immobility of the insect and hence reliance on physiological solutions, as opposed to the Sahelian dry season, which restricts reproduction exclusively, we propose that behavioral changes play an important role in complementing physiological changes in this strategy. PMID:24933461

  13. Evidence for Pleistocene Population Divergence and Expansion of Anopheles albimanus in Southern Central America

    PubMed Central

    Loaiza, Jose R.; Scott, Marilyn E.; Bermingham, Eldredge; Rovira, Jose; Conn, Jan E.

    2010-01-01

    The micro-geographic structure of Anopheles albimanus was studied in southern Central America using partial sequences of the mtDNA cytochrome oxidase subunit I gene (COI). Analysis of molecular variance supported significant genetic structure between populations from Costa Rica and western Panama versus those from central-eastern Panama (ΦCT = 0.33), whereas the within group divergence was shallow and statistically insignificant (ΦST = 0.08). Furthermore, a statistical parsimony network depicted three divergent groups of haplotypes that were not evenly distributed across the study area. Our findings are in partial agreement with previous studies, yet they do not support physical barriers to gene flow or contemporary isolation by distance in this region. Instead, three co-occurring groups of An. albimanus may be the result of multiple introductions, most likely caused by historical fragmentation and subsequent secondary contact. In addition, the molecular signature of population expansion of An. albimanus was detected in central-eastern Panama approximately 22,000 years ago (95% confidence interval [CI] 10,183–38,169). We hypothesize that the population structure of An. albimanus, as determined by our COI locus analysis, is the result of late Pleistocene climatic changes in northern South America. PMID:20065014

  14. Isolation of Bacillus sphaericus from Lombok Island, Indonesia, and Their Toxicity against Anopheles aconitus

    PubMed Central

    Suryadi, Bambang Fajar; Yanuwiadi, Bagyo; Ardyati, Tri; Suharjono

    2015-01-01

    Malaria is endemic to Lombok Island, Indonesia. One approach to suppress malaria spread is to eliminate anopheline larvae in their habitat and the environmentally safe agent is bacteria, that is, Bacillus sphaericus. However, there is no information regarding local isolate of B. sphaericus that is toxic to mosquito larvae from Lombok. The aims of the study were to isolate B. sphaericus from soil in areas close to beach surrounding Lombok Island and to test their toxicity against 3rd instar Anopheles aconitus larvae. Soil samples were collected from 20 different sampling locations from Lombok Island and homogenized with sterile physiological salt solution. Suspension was heat-shocked at 80°C for 30 minutes and then spread onto antibiotic-supplemented NYSM solid medium. Colonies grown were characterized and subjected to initial toxicity test against anopheline larvae. Isolates with more than 50% killing percentage were subjected to bioassay testing against anopheline larvae. From 20 locations, 1 isolate showed mild toxicity (namely, isolate MNT) and 2 isolates showed high toxicity (namely, isolates SLG and TJL2) against An. aconitus. Those 3 isolates were potentially useful isolates, as they killed almost all larvae in 24 hours. The discovery of toxic indigenous isolates of B. sphaericus from Lombok Island opens opportunity to develop a biopesticide from local resources. PMID:26788061

  15. Population control of the malaria vector Anopheles pseudopunctipennis by habitat manipulation.

    PubMed Central

    Bond, J. Guillermo; Rojas, Julio C.; Arredondo-Jiménez, Juan I.; Quiroz-Martínez, Humberto; Valle, Javier; Williams, Trevor

    2004-01-01

    Insect vector-borne diseases continue to present a major challenge to human health. Understanding the factors that regulate the size of mosquito populations is considered fundamental to the ability to predict disease transmission rates and for vector population control. The mosquito, Anopheles pseudopunctipennis, a vector of Plasmodium spp., breeds in riverside pools containing filamentous algae in Mesoamerica. Breeding pools along 3 km sections of the River Coatan, Chiapas, Mexico were subjected to algal extraction or left as controls in a cross-over trial extending over 2 years. Initial densities of An. pseudopunctipennis larvae were directly proportional to the prevalence of filamentous algae in each breeding site. The extraction of algae brought about a striking decline in the density of An. pseudopunctipennis larvae sustained for about six weeks, and a concurrent reduction in the adult population in both years of the study. Mark-release experiments indicated that dispersal from adjacent untreated areas was unlikely to exert an important influence on the magnitude of mosquito control that we observed. Habitat manipulation by extraction of filamentous algae offers a unique opportunity for sustainable control of this malaria vector. This technique may represent a valuable intervention, complimenting insecticide spraying of households, to minimize Plasmodium transmission rates in Mesoamerica. PMID:15475337

  16. Modelling Anopheles gambiae s.s. Population Dynamics with Temperature- and Age-Dependent Survival.

    PubMed

    Christiansen-Jucht, Céline; Erguler, Kamil; Shek, Chee Yan; Basáñez, María-Gloria; Parham, Paul E

    2015-05-28

    Climate change and global warming are emerging as important threats to human health, particularly through the potential increase in vector- and water-borne diseases. Environmental variables are known to affect substantially the population dynamics and abundance of the poikilothermic vectors of disease, but the exact extent of this sensitivity is not well established. Focusing on malaria and its main vector in Africa, Anopheles gambiae sensu stricto, we present a set of novel mathematical models of climate-driven mosquito population dynamics motivated by experimental data suggesting that in An. gambiae, mortality is temperature and age dependent. We compared the performance of these models to that of a "standard" model ignoring age dependence. We used a longitudinal dataset of vector abundance over 36 months in sub-Saharan Africa for comparison between models that incorporate age dependence and one that does not, and observe that age-dependent models consistently fitted the data better than the reference model. This highlights that including age dependence in the vector component of mosquito-borne disease models may be important to predict more reliably disease transmission dynamics. Further data and studies are needed to enable improved fitting, leading to more accurate and informative model predictions for the An. gambiae malaria vector as well as for other disease vectors.

  17. Genome-Wide Divergence in the West-African Malaria Vector Anopheles melas.

    PubMed

    Deitz, Kevin C; Athrey, Giridhar A; Jawara, Musa; Overgaard, Hans J; Matias, Abrahan; Slotman, Michel A

    2016-09-08

    Anopheles melas is a member of the recently diverged An. gambiae species complex, a model for speciation studies, and is a locally important malaria vector along the West-African coast where it breeds in brackish water. A recent population genetic study of An. melas revealed species-level genetic differentiation between three population clusters. An. melas West extends from The Gambia to the village of Tiko, Cameroon. The other mainland cluster, An. melas South, extends from the southern Cameroonian village of Ipono to Angola. Bioko Island, Equatorial Guinea An. melas populations are genetically isolated from mainland populations. To examine how genetic differentiation between these An. melas forms is distributed across their genomes, we conducted a genome-wide analysis of genetic differentiation and selection using whole genome sequencing data of pooled individuals (Pool-seq) from a representative population of each cluster. The An. melas forms exhibit high levels of genetic differentiation throughout their genomes, including the presence of numerous fixed differences between clusters. Although the level of divergence between the clusters is on a par with that of other species within the An. gambiae complex, patterns of genome-wide divergence and diversity do not provide evidence for the presence of pre- and/or postmating isolating mechanisms in the form of speciation islands. These results are consistent with an allopatric divergence process with little or no introgression.

  18. Unraveling dual feeding associated molecular complexity of salivary glands in the mosquito Anopheles culicifacies

    PubMed Central

    Sharma, Punita; Sharma, Swati; Mishra, Ashwani Kumar; Thomas, Tina; Das De, Tanwee; Rohilla, Suman Lata; Singh, Namita; Pandey, Kailash C.; Valecha, Neena; Dixit, Rajnikant

    2015-01-01

    ABSTRACT Mosquito salivary glands are well known to facilitate meal acquisition, however the fundamental question on how adult female salivary gland manages molecular responses during sugar versus blood meal uptake remains unanswered. To investigate these responses, we analyzed a total of 58.5 million raw reads generated from two independent RNAseq libraries of the salivary glands collected from 3–4 day-old sugar and blood fed Anopheles culicifacies mosquitoes. Comprehensive functional annotation analysis of 10,931 contigs unraveled that salivary glands may encode diverse nature of proteins in response to distinct physiological feeding status. Digital gene expression analysis and PCR validation indicated that first blood meal significantly alters the molecular architecture of the salivary glands. Comparative microscopic analysis also revealed that first blood meal uptake not only causes an alteration of at least 12–22% of morphological features of the salivary glands but also results in cellular changes e.g. apoptosis, confirming together that adult female salivary glands are specialized organs to manage meal specific responses. Unraveling the underlying mechanism of mosquito salivary gene expression, controlling dual feeding associated responses may provide a new opportunity to control vector borne diseases. PMID:26163527

  19. Anthropogenic Habitat Disturbance and Ecological Divergence between Incipient Species of the Malaria Mosquito Anopheles gambiae

    PubMed Central

    Kamdem, Colince; Tene Fossog, Billy; Simard, Frédéric; Etouna, Joachim; Ndo, Cyrille; Kengne, Pierre; Boussès, Philippe; Etoa, François-Xavier; Awono-Ambene, Parfait; Fontenille, Didier; Antonio-Nkondjio, Christophe; Besansky, Nora J.; Costantini, Carlo

    2012-01-01

    Background Anthropogenic habitat disturbance is a prime cause in the current trend of the Earth’s reduction in biodiversity. Here we show that the human footprint on the Central African rainforest, which is resulting in deforestation and growth of densely populated urban agglomerates, is associated to ecological divergence and cryptic speciation leading to adaptive radiation within the major malaria mosquito Anopheles gambiae. Methodology/Principal Findings In southern Cameroon, the frequency of two molecular forms–M and S–among which reproductive isolation is strong but still incomplete, was correlated to an index of urbanisation extracted from remotely sensed data, expressed as the proportion of built-up surface in each sampling unit. The two forms markedly segregated along an urbanisation gradient forming a bimodal cline of ∼6-km width: the S form was exclusive to the rural habitat, whereas only the M form was present in the core of densely urbanised settings, co-occurring at times in the same polluted larval habitats of the southern house mosquito Culex quinquefasciatus–a species association that was not historically recorded before. Conclusions/Significance Our results indicate that when humans create novel habitats and ecological heterogeneities, they can provide evolutionary opportunities for rapid adaptive niche shifts associated with lineage divergence, whose consequences upon malaria transmission might be significant. PMID:22745756

  20. Pegasus, a small terminal inverted repeat transposable element found in the white gene of Anopheles gambiae.

    PubMed

    Besansky, N J; Mukabayire, O; Bedell, J A; Lusz, H

    1996-10-01

    Pegasus, a novel transposable element, was discovered as a length polymorphism in the white gene of Anopheles gambiae. Sequence analysis revealed that this 535 bp element was flanked by 8 bp target site duplications and 8 bp perfect terminal inverted repeats similar to those found in many members of the Tc1 family. Its small size and lack of long open reading frames preclude protein coding capacity. Southern analysis and in situ hybridization to polytene chromosomes demonstrated that Pegasus occurs in approximately 30 copies in the genomes of An. gambiae and its sibling species and is homogenous in structure but polymorphic in chromosomal location. Characterization of five additional elements by sequencing revealed nucleotide identities of 95% to 99%. Of 30 Pegasus-containing phage clones examined by PCR, only one contained an element exceeding 535 bp in length, due to the insertion of another transposable element-like sequence. Thus, the majority, if not all, extant Pegasus elements may be defective copies of a complete element whose contemporary existence in An. gambiae is uncertain. No Pegasus-hybridizing sequences were detected in nine other anophelines and three culicines examined, suggesting a very limited taxonomic distribution.

  1. Life cycle transcriptome of the malaria mosquito Anopheles gambiae and comparison with the fruitfly Drosophila melanogaster.

    PubMed

    Koutsos, Anastasios C; Blass, Claudia; Meister, Stephan; Schmidt, Sabine; MacCallum, Robert M; Soares, Marcelo B; Collins, Frank H; Benes, Vladimir; Zdobnov, Evgeny; Kafatos, Fotis C; Christophides, George K

    2007-07-03

    The African mosquito Anopheles gambiae is the major vector of human malaria. We report a genome-wide survey of mosquito gene expression profiles clustered temporally into developmental programs and spatially into adult tissue-specific patterns. Global expression analysis shows that genes that belong to related functional categories or that encode the same or functionally linked protein domains are associated with characteristic developmental programs or tissue patterns. Comparative analysis of our data together with data published from Drosophila melanogaster reveal an overall strong and positive correlation of developmental expression between orthologous genes. The degree of correlation varies, depending on association of orthologs with certain developmental programs or functional groups. Interestingly, the similarity of gene expression is not correlated with the coding sequence similarity of orthologs, indicating that expression profiles and coding sequences evolve independently. In addition to providing a comprehensive view of temporal and spatial gene expression during the A. gambiae life cycle, this large-scale comparative transcriptomic analysis has detected important evolutionary features of insect transcriptomes.

  2. Metabolic and target-site mechanisms combine to confer strong DDT resistance in Anopheles gambiae.

    PubMed

    Mitchell, Sara N; Rigden, Daniel J; Dowd, Andrew J; Lu, Fang; Wilding, Craig S; Weetman, David; Dadzie, Samuel; Jenkins, Adam M; Regna, Kimberly; Boko, Pelagie; Djogbenou, Luc; Muskavitch, Marc A T; Ranson, Hilary; Paine, Mark J I; Mayans, Olga; Donnelly, Martin J

    2014-01-01

    The development of resistance to insecticides has become a classic exemplar of evolution occurring within human time scales. In this study we demonstrate how resistance to DDT in the major African malaria vector Anopheles gambiae is a result of both target-site resistance mechanisms that have introgressed between incipient species (the M- and S-molecular forms) and allelic variants in a DDT-detoxifying enzyme. Sequencing of the detoxification enzyme, Gste2, from DDT resistant and susceptible strains of An. gambiae, revealed a non-synonymous polymorphism (I114T), proximal to the DDT binding domain, which segregated with strain phenotype. Recombinant protein expression and DDT metabolism analysis revealed that the proteins from the susceptible strain lost activity at higher DDT concentrations, characteristic of substrate inhibition. The effect of I114T on GSTE2 protein structure was explored through X-ray crystallography. The amino acid exchange in the DDT-resistant strain introduced a hydroxyl group nearby the hydrophobic DDT-binding region. The exchange does not result in structural alterations but is predicted to facilitate local dynamics and enzyme activity. Expression of both wild-type and 114T alleles the allele in Drosophila conferred an increase in DDT tolerance. The 114T mutation was significantly associated with DDT resistance in wild caught M-form populations and acts in concert with target-site mutations in the voltage gated sodium channel (Vgsc-1575Y and Vgsc-1014F) to confer extreme levels of DDT resistance in wild caught An. gambiae.

  3. Larval density dependence in Anopheles gambiae s.s., the major African vector of malaria

    PubMed Central

    Muriu, Simon M.; Coulson, Tim; Mbogo, Charles M.; Godfray, H. Charles J.

    2017-01-01

    Summary Anopheles gambiae sensu stricto is the most important vector of malaria in Africa although relatively little is known about the density-dependent processes determining its population size.Mosquito larval density was manipulated under semi-natural conditions using artificial larval breeding sites placed in the field in coastal Kenya; two experiments were conducted: one manipulating the density of a single cohort of larvae across a range of densities and the other employing fewer densities but with the treatments crossed with four treatments manipulating predator access.In the first experiment, larval survival, development rate and the size of the adult mosquito all decreased with larval density (controlling for block effects between 23% and 31% of the variance in the data could be explained by density).In the second experiment, the effects of predator manipulation were not significant, but again we observed strong density dependence in larval survival (explaining 30% of the variance).The results are compared with laboratory studies of A. gambiae larval competition and the few other studies conducted in the field, and the consequences for malaria control are discussed PMID:23163565

  4. Distribution of the molecular forms of Anopheles gambiae and pyrethroid knock down resistance gene in Nigeria.

    PubMed

    Awolola, T S; Oyewole, I O; Amajoh, C N; Idowu, E T; Ajayi, M B; Oduola, A; Manafa, O U; Ibrahim, K; Koekemoer, L L; Coetzee, M

    2005-09-01

    We investigated the distribution of the molecular M and S forms of Anopheles gambiae and the knock down resistance (kdr) gene associated with pyrethroid and DDT resistance in A. gambiae s.s. at 13 localities across Nigeria. Two-three days old adult female mosquito reared from larval collections were tested using standard WHO procedures, diagnostic test kits and impregnated papers to assess their pyrethroid resistance status. Specimens were identified by PCR assays and characterized for the kdr gene. DNA from adult A. gambiae s.s. collected from human dwellings were also tested for the presence of the kdr gene. The overall collection was a mix of the molecular M and S forms across the mangrove (63:37%), forest (56:44%), and transitional (36:64%) ecotypes, but almost a pure collection of the S form in the Guinea and Sudan-savanna. Results of insecticide susceptibility tests showed that mosquitoes sampled at seven localities were susceptible to permethrin, deltamethrin, and DDT, but populations of A. gambiae resistant to these insecticides were recorded at six other localities mainly in the transitional and Guinea-savanna ecotypes. The kdr gene was found only in the molecular S forms, including areas where both forms were sympatric. The overall kdr frequency was low: <47% in forest, 37-48% in the transitional, and 45-53% in Guinea-savanna. The data suggest that pyrethroid resistance in A. gambiae in Nigeria is not as widespread when compared to neighbouring West African countries.

  5. Genome-Wide Divergence in the West-African Malaria Vector Anopheles melas

    PubMed Central

    Deitz, Kevin C.; Athrey, Giridhar A.; Jawara, Musa; Overgaard, Hans J.; Matias, Abrahan; Slotman, Michel A.

    2016-01-01

    Anopheles melas is a member of the recently diverged An. gambiae species complex, a model for speciation studies, and is a locally important malaria vector along the West-African coast where it breeds in brackish water. A recent population genetic study of An. melas revealed species-level genetic differentiation between three population clusters. An. melas West extends from The Gambia to the village of Tiko, Cameroon. The other mainland cluster, An. melas South, extends from the southern Cameroonian village of Ipono to Angola. Bioko Island, Equatorial Guinea An. melas populations are genetically isolated from mainland populations. To examine how genetic differentiation between these An. melas forms is distributed across their genomes, we conducted a genome-wide analysis of genetic differentiation and selection using whole genome sequencing data of pooled individuals (Pool-seq) from a representative population of each cluster. The An. melas forms exhibit high levels of genetic differentiation throughout their genomes, including the presence of numerous fixed differences between clusters. Although the level of divergence between the clusters is on a par with that of other species within the An. gambiae complex, patterns of genome-wide divergence and diversity do not provide evidence for the presence of pre- and/or postmating isolating mechanisms in the form of speciation islands. These results are consistent with an allopatric divergence process with little or no introgression. PMID:27466271

  6. Species abundance and insecticide resistance of Anopheles gambiae in selected areas of Ghana and Burkina Faso.

    PubMed

    Yawson, A E; McCall, P J; Wilson, M D; Donnelly, M J

    2004-12-01

    The Ghanaian National Malaria Control Programme has prioritized insecticide-treated materials as a key strategy for malaria control. We report on a survey of the distribution of the molecular forms of Anopheles gambiae Giles (Diptera: Culicidae) and insecticide resistance (the kdr mutation), carried out by sampling mosquitoes from 11 locations in Ghana and one additional site in Burkina Faso. The molecular M and S forms of An. gambiae were found to occur in sympatry in southern Ghana. The S form predominated throughout its distribution in the coastal savannah, except at one location in the strand and mangrove zone where rice was cultivated. The M form was the only form collected in northern Ghana and was the predominant form (97.5%) in Burkina Faso. No M/S hybrids were detected. The kdr mutation was observed at very high frequencies (98-100%) within the S form but reached a maximum of only 3.38% in the M form in one population at an irrigation scheme in the Ghanaian coastal savannah zone.

  7. Comparison of the functional features of the pump organs of Anopheles sinensis and Aedes togoi

    PubMed Central

    Ha, Young-Ran; Lee, Seung-Chul; Seo, Seung-Jun; Ryu, Jeongeun; Lee, Dong-Kyu; Lee, Sang-Joon

    2015-01-01

    Mosquitoes act as vectors for severe tropical diseases. Mosquito-borne diseases are affected by various factors such as environmental conditions, host body susceptibility, and mosquito feeding behavior. Among these factors, feeding behavior is affected by the feeding pump system located inside the mosquito head and also depends on the species of mosquito. Therefore, the 3D morphological structures of the feeding pumps of Aedes togoi and Anopheles sinensis were comparatively investigated using synchrotron X-ray microscopic computed tomography. In addition, the feeding behaviors of their pumping organs were also investigated using a 2D X-ray micro-imaging technique. An. sinensis, a malarial vector mosquito, had a larger feeding pump volume than Ae. togoi in the static or resting position. Interestingly, the two species of mosquitoes exhibited different feeding behaviors. Ae. togoi had a higher feeding frequency and expansion ratio than An. sinensis. Ae. togoi also exhibited F-actin localization more clearly. These distinctive variations in feeding volumes and behaviors provide essential insight into the blood-feeding mechanisms of female mosquitoes as vectors for tropical diseases. PMID:26464043

  8. Analysis of the metabolome of Anopheles gambiae mosquito after exposure to Mycobacterium ulcerans

    PubMed Central

    Hoxmeier, J. Charles; Thompson, Brice D.; Broeckling, Corey D.; Small, Pamela; Foy, Brian D.; Prenni, Jessica; Dobos, Karen M.

    2015-01-01

    Infection with Mycobacterium ulcerans causes Buruli Ulcer, a neglected tropical disease. Mosquito vectors are suspected to participate in the transmission and environmental maintenance of the bacterium. However, mechanisms and consequences of mosquito contamination by M. ulcerans are not well understood. We evaluated the metabolome of the Anopheles gambiae mosquito to profile the metabolic changes associated with bacterial colonization. Contamination of mosquitoes with live M. ulcerans bacilli results in disruptions to lipid metabolic pathways of the mosquito, specifically the utilization of glycerolipid molecules, an affect that was not observed in mosquitoes exposed to dead M. ulcerans. These results are consistent with aberrations of lipid metabolism described in other mycobacterial infections, implying global host-pathogen interactions shared across diverse saprophytic and pathogenic mycobacterial species. This study implicates features of the bacterium, such as the putative M. ulcerans encoded phospholipase enzyme, which promote virulence, survival, and active adaptation in concert with mosquito development, and provides significant groundwork for enhanced studies of the vector-pathogen interactions using metabolomics profiling. Lastly, metabolic and survival data suggest an interaction which is unlikely to contribute to transmission of M. ulcerans by A. gambiae and more likely to contribute to persistence of M. ulcerans in waters cohabitated by both organisms. PMID:25784490

  9. Comparative Genomics of Odorant Binding Proteins in Anopheles gambiae, Aedes aegypti, and Culex quinquefasciatus

    PubMed Central

    Manoharan, Malini; Ng Fuk Chong, Matthieu; Vaïtinadapoulé, Aurore; Frumence, Etienne; Sowdhamini, Ramanathan; Offmann, Bernard

    2013-01-01

    About 1 million people in the world die each year from diseases spread by mosquitoes, and understanding the mechanism of host identification by the mosquitoes through olfaction is at stake. The role of odorant binding proteins (OBPs) in the primary molecular events of olfaction in mosquitoes is becoming an important focus of biological research in this area. Here, we present a comprehensive comparative genomics study of OBPs in the three disease-transmitting mosquito species Anopheles gambiae, Aedes aegypti, and Culex quinquefasciatus starting with the identification of 110 new OBPs in these three genomes. We have characterized their genomic distribution and orthologous and phylogenetic relationships. The diversity and expansion observed with respect to the Aedes and Culex genomes suggests that the OBP gene family acquired functional diversity concurrently with functional constraints posed on these two species. Sequences with unique features have been characterized such as the “two-domain OBPs” (previously known as Atypical OBPs) and “MinusC OBPs” in mosquito genomes. The extensive comparative genomics featured in this work hence provides useful primary insights into the role of OBPs in the molecular adaptations of mosquito olfactory system and could provide more clues for the identification of potential targets for insect repellants and attractants. PMID:23292137

  10. Laser dosimetry for disabling anopheles stephensi mosquitoes in-flight (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Keller, Matthew D.; Norton, Bryan J.; Rutschman, Phil; Farrar, David J.; Marvit, Maclen; Makagon, Artyom

    2016-03-01

    The Photonic Fence is a system designed to detect mosquitoes and other pestilent flying insects in an active region and to apply lethal doses of laser light to them. Previously, we determined lethal fluence levels for a variety of lasers and pulse conditions on anesthetized Anopheles stephensi mosquitoes. In this work, similar studies were performed while the bugs were freely flying within transparent cages. Dose-response curves were created for various beam diameter, pulse width, and power conditions at 455 nm, 532 nm, 1064nm, and 1540 nm wavelengths. Besides mortality outcomes, the flight behavior of the bugs and the performance of the tracking system were monitored for consistency and to ensure that they had no impact on the mortality outcomes. As in anesthetized experiments, the visible wavelengths required significantly less fluence than near infrared wavelengths to reliably disable bugs. For the visible wavelengths, lethal fluence values were generally equivalent to those found in anesthetized dosing, while near infrared wavelengths required approximately twice the fluence compared with anesthetized experiments. The performance of the optical tracking system remained highly stable throughout the experiments, and it was found not to influence mortality results for pulse widths up to 25 ms. In general, keeping energy constant while decreasing power and increasing pulse width reduced mortality levels. The results of this study further affirm the practicality of using optical approaches to protect people and crops from flying insects.

  11. GNBP domain of Anopheles darlingi: are polymorphic inversions and gene variation related to adaptive evolution?

    PubMed

    Bridi, L C; Rafael, M S

    2016-02-01

    Anopheles darlingi is the main malaria vector in humans in South America. In the Amazon basin, it lives along the banks of rivers and lakes, which responds to the annual hydrological cycle (dry season and rainy season). In these breeding sites, the larvae of this mosquito feed on decomposing organic and microorganisms, which can be pathogenic and trigger the activation of innate immune system pathways, such as proteins Gram-negative binding protein (GNBP). Such environmental changes affect the occurrence of polymorphic inversions especially at the heterozygote frequency, which confer adaptative advantage compared to homozygous inversions. We mapped the GNBP probe to the An. darlingi 2Rd inversion by fluorescent in situ hybridization (FISH), which was a good indicator of the GNBP immune response related to the chromosomal polymorphic inversions and adaptative evolution. To better understand the evolutionary relations and time of divergence of the GNBP of An. darlingi, we compared it with nine other mosquito GNBPs. The results of the phylogenetic analysis of the GNBP sequence between the species of mosquitoes demonstrated three clades. Clade I and II included the GNBPB5 sequence, and clade III the sequence of GNBPB1. Most of these sequences of GNBP analyzed were homologous with that of subfamily B, including that of An. gambiae (87 %), therefore suggesting that GNBP of An. darling belongs to subfamily B. This work helps us understand the role of inversion polymorphism in evolution of An. darlingi.

  12. High Genetic Differentiation between the M and S Molecular Forms of Anopheles gambiae in Africa

    PubMed Central

    Esnault, Caroline; Boulesteix, Matthieu; Duchemin, Jean Bernard; Koffi, Alphonsine A.; Chandre, Fabrice; Dabiré, Roch; Robert, Vincent; Simard, Frédéric; Tripet, Frédéric; Donnelly, Martin J.; Fontenille, Didier; Biémont, Christian

    2008-01-01

    Background Anopheles gambiae, a major vector of malaria, is widely distributed throughout sub-Saharan Africa. In an attempt to eliminate infective mosquitoes, researchers are trying to develop transgenic strains that are refractory to the Plasmodium parasite. Before any release of transgenic mosquitoes can be envisaged, we need an accurate picture of the differentiation between the two molecular forms of An. gambiae, termed M and S, which are of uncertain taxonomic status. Methodology/Principal Findings Insertion patterns of three transposable elements (TEs) were determined in populations from Benin, Burkina Faso, Cameroon, Ghana, Ivory Coast, Madagascar, Mali, Mozambique, Niger, and Tanzania, using Transposon Display, a TE-anchored strategy based on Amplified Fragment Length Polymorphism. The results reveal a clear differentiation between the M and S forms, whatever their geographical origin, suggesting an incipient speciation process. Conclusions/Significance Any attempt to control the transmission of malaria by An. gambiae using either conventional or novel technologies must take the M/S genetic differentiation into account. In addition, we localized three TE insertion sites that were present either in every individual or at a high frequency in the M molecular form. These sites were found to be located outside the chromosomal regions that are suspected of involvement in the speciation event between the two forms. This suggests that these chromosomal regions are either larger than previously thought, or there are additional differentiated genomic regions interspersed with undifferentiated regions. PMID:18414665

  13. Exploring Proteins in Anopheles gambiae Male and Female Antennae through MALDI Mass Spectrometry Profiling

    PubMed Central

    Dani, Francesca R.; Francese, Simona; Mastrobuoni, Guido; Felicioli, Antonio; Caputo, Beniamino; Simard, Frederic; Pieraccini, Giuseppe; Moneti, Gloriano; Coluzzi, Mario; della Torre, Alessandra; Turillazzi, Stefano

    2008-01-01

    MALDI profiling and imaging mass spectrometry (IMS) are novel techniques for direct analysis of peptides and small proteins in biological tissues. In this work we applied them to the study of Anopheles gambiae antennae, with the aim of analysing expression of soluble proteins involved in olfaction perireceptor events. MALDI spectra obtained by direct profiling on single antennae and by the analysis of extracts, showed similar profiles, although spectra obtained through profiling had a richer ion population and higher signal to noise ratio. Male and female antennae showed distinct protein profiles. MALDI imaging experiments were also performed and differences were observed in the localization of some proteins. Two proteins were identified through high resolution measurement and top-down MS/MS experiments. A 8 kDa protein only present in the male antennae matched with an unannotated sequence of the An. gambiae genome, while the presence of odorant binding protein 9 (OBP-9) was confirmed through experiments of 2-DE, followed by MS and MS/MS analysis of digested spots. This work shows that MALDI MS profiling is a technique suitable for the analysis of proteins of small and medium MW in insect appendices, and allows obtaining data for several specimens which can be investigated for differences between groups. Proteins of interest can be identified through other complementary MS approaches. PMID:18665262

  14. Brazilian Anopheles darlingi Root (Diptera: Culicidae) Clusters by Major Biogeographical Region.

    PubMed

    Emerson, Kevin J; Conn, Jan E; Bergo, Eduardo S; Randel, Melissa A; Sallum, Maria Anice M

    2015-01-01

    The major drivers of the extensive biodiversity of the Neotropics are proposed to be geological and tectonic events together with Pliocene and Pleistocene environmental and climatic change. Geographical barriers represented by the rivers Amazonas/Solimões, the Andes and the coastal mountain ranges in eastern Brazil have been hypothesized to lead to diversification within the primary malaria vector, Anopheles (Nyssorhynchus) darlingi Root, which primarily inhabits rainforest. To test this biogeographical hypothesis, we analyzed 786 single nucleotide polymorphisms (SNPs) in 12 populations of An. darlingi from across the complex Brazilian landscape. Both model-based (STRUCTURE) and non-model-based (Principal Components and Discriminant Analysis) analysis of population structure detected three major genetic clusters that correspond with newly described Neotropical biogeographical regions: 1) Atlantic Forest province (= southeast population); 2) Parana Forest province (= West Atlantic forest population, with one Chacoan population - SP); and 3) Brazilian dominion population (= Amazonian population with one Chacoan population - TO). Significant levels of pairwise genetic divergences were found among the three clusters, allele sharing among clusters was negligible, and geographical distance did not contribute to differentiation. We infer that the Atlantic forest coastal mountain range limited dispersal between the Atlantic Forest province and the Parana Forest province populations, and that the large, diagonal open vegetation region of the Chacoan dominion dramatically reduced dispersal between the Parana and Brazilian dominion populations. We hypothesize that the three genetic clusters may represent three putative species.

  15. Visual and olfactory associative learning in the malaria vector Anopheles gambiae sensu stricto

    PubMed Central

    2012-01-01

    Background Memory and learning are critical aspects of the ecology of insect vectors of human pathogens because of their potential effects on contacts between vectors and their hosts. Despite this epidemiological importance, there have been only a limited number of studies investigating associative learning in insect vector species and none on Anopheline mosquitoes. Methods A simple behavioural assays was developed to study visual and olfactory associative learning in Anopheles gambiae, the main vector of malaria in Africa. Two contrasted membrane qualities or levels of blood palatability were used as reinforcing stimuli for bi-directional conditioning during blood feeding. Results Under such experimental conditions An. gambiae females learned very rapidly to associate visual (chequered and white patterns) and olfactory cues (presence and absence of cheese or Citronella smell) with the reinforcing stimuli (bloodmeal quality) and remembered the association for up to three days. Associative learning significantly increased with the strength of the conditioning stimuli used. Importantly, learning sometimes occurred faster when a positive reinforcing stimulus (palatable blood) was associated with an innately preferred cue (such as a darker visual pattern). However, the use of too attractive a cue (e.g. Shropshire cheese smell) was counter-productive and decreased learning success. Conclusions The results address an important knowledge gap in mosquito ecology and emphasize the role of associative memory for An. gambiae's host finding and blood-feeding behaviour with important potential implications for vector control. PMID:22284012

  16. Avoidance Behavior to Essential Oils by Anopheles minimus, a Malaria Vector in Thailand.

    PubMed

    Nararak, Jirod; Sathantriphop, Sunaiyana; Chauhan, Kamal; Tantakom, Siripun; Eiden, Amanda L; Chareonviriyaphap, Theeraphap

    2016-03-01

    Essential oils extracted from 4 different plant species--citronella (Cymbopogon nardus), hairy basil (Ocimum americanum), sweet basil (Ocimum basilicum), and vetiver (Vetiveria zizanioides)-were investigated for their irritant and repellent activities against Anopheles minimus, using an excito-repellency test system. Pure essential oils were used in absolute ethanol at the concentrations of 0.5%, 1%, 2.5%, and 5% (v/v) compared with deet. At the lowest concentration of 0.5%, hairy basil displayed the best irritant and repellent effects against An. minimus. Citronella and vetiver at 1-5% showed strong irritant effects with>80% escape, while repellent effects of both oils were observed at 1% and 2.5% citronella (73-89% escape) and at 5% vetiver (83.9% escape). Sweet basil had only moderate irritant action at 5% concentration (69.6% escape) and slightly repellent on test mosquitoes (<50% escape). The results found that hairy basil, citronella, and vetiver are promising potential mosquito repellent products for protection against An. minimus.

  17. THE SALIVARY TRANSCRIPTOME OF Anopheles gambiae (DIPTERA: CULICIDAE) LARVAE: A MICROARRAY-BASED ANALYSIS

    PubMed Central

    Neira Oviedo, M.; Ribeiro, J.M.C.; Heyland, A.; VanEkeris, L.; Moroz, T.; Linser, P.J.

    2009-01-01

    In spite of the many recent developments in the field of vector sialomics, the salivary glands of larval mosquitoes have been largely unexplored. We used whole-transcriptome microarray analysis to create a gene-expression profile of the salivary gland tissue of fourth-instar Anopheles gambiae larvae, and compare it to the gene-expression profile of a matching group of whole larvae. We identified a total of 221 probes with expression values that were (a) significantly enriched in the salivary glands, and (b) sufficiently annotated as to allow the prediction of the presence/absence of signal peptides in their corresponding gene products. Based on available annotation of the protein sequences associated with these probes, we propose that the main roles of larval salivary secretions include: (a) immune response, (b) mouthpart lubrication, (c) nutrient metabolism, and (d) xenobiotic detoxification. Other highlights of the study include the cloning of a transcript encoding a previously unknown salivary defensin (AgDef5), the confirmation of mucus secretion by the larval salivary glands, and the first report of salivary lipocalins in the Culicidae. PMID:19328852

  18. Suitability of monotypic and mixed diets for Anopheles hermsi larval development.

    PubMed

    Beasley, Donald A; Walton, William E

    2016-06-01

    The developmental time and survival to eclosion of Anopheles hermsi Barr & Guptavanij fed monotypic and mixed diets of ten food types were examined in laboratory studies. Larvae fed monotypic diets containing animal detritus (freeze-dried rotifers, freeze-dried Daphnia pulicaria, and TetraMin® fish food flakes) and the mixotrophic protistan Cryptomonas ovata developed faster and survived better than larvae that were fed other monotypic diets. Survival to adulthood of larvae fed several concentrations of the diatom Planothidium (=Achnanthes) lanceolatum was poor (<13%) and larval development time was approximately twice that of larvae fed TetraMin® fish food flakes, the standard laboratory diet. Larvae fed monotypic diets containing prokaryotes (bacteria [Bacillus cereus] and cyanobacteria [Oscillatoria prolifera]) and brewer's yeast (Saccharomyces cerevisiae) failed to survive beyond the 1(st) and 2(nd) instar, respectively. Larvae fed only chlorophytes, single-celled Chlamydomonas reinhardtii and filamentous Spirogyra communis, failed to complete larval development, regardless of the concentration tested. Cohorts fed a combination of food types (mixed diets) usually developed better than cohorts fed monotypic diets. Food types that failed to support complete development when fed alone often facilitated development to adulthood when fed in combination with food types containing >1% C20 polyunsaturated fatty acids as total fat, but regardless of essential fatty acid content, algae that produced mucilage and filaments that sank out of the feeding zone were poor quality diets.

  19. Isozyme evidence for three sibling species in the Anopheles sundaicus complex from Indonesia.

    PubMed

    Sukowati, S; Baimai, V; Harun, S; Dasuki, Y; Andris, H; Efriwati, M

    1999-10-01

    Electrophoretic studies of isoenzymes in three chromosomally distinct forms (A, B and C) of the mosquito Anopheles sundaicus Theobald (Diptera: Culiciae) were undertaken on wild samples collected from six geographically isolated populations in Indonesia. Analyses of 12 enzyme systems comprising 15 loci revealed significant allelic variations, genetic polymorphism, within and among the populations of the An. sundaicus complex. Phylogenetic dendrograms produced by analysis using the Biosys-1 program based on UPGMA methods show that all the populations of form A fall into one cluster, which is closely related to the form C cluster, whereas the populations of form B belong to a more distinct cluster. Allelic frequency and Wright's F statistics of Mpi (mannose phosphate isomerase) are sufficient to identify individuals of each cytological form. This isozyme data correlates with our previous cytological evidence for the existence of three isomorphic species within the taxon An. sundaicus in Indonesia. These three species of the An. sundaicus complex were found together sympatrically at one locality, Asahan in North Sumatra.

  20. A Wickerhamomyces anomalus Killer Strain in the Malaria Vector Anopheles stephensi

    PubMed Central

    Valzano, Matteo; Damiani, Claudia; Epis, Sara; Gabrielli, Maria Gabriella; Conti, Stefania; Polonelli, Luciano; Bandi, Claudio; Favia, Guido; Ricci, Irene

    2014-01-01

    The yeast Wickerhamomyces anomalus has been investigated for several years for its wide biotechnological potential, especially for applications in the food industry. Specifically, the antimicrobial activity of this yeast, associated with the production of Killer Toxins (KTs), has attracted a great deal of attention. The strains of W. anomalus able to produce KTs, called “killer” yeasts, have been shown to be highly competitive in the environment. Different W. anomalus strains have been isolated from diverse habitats and recently even from insects. In the malaria mosquito vector Anopheles stephensi these yeasts have been detected in the midgut and gonads. Here we show that the strain of W. anomalus isolated from An. stephensi, namely WaF17.12, is a killer yeast able to produce a KT in a cell-free medium (in vitro) as well as in the mosquito body (in vivo). We showed a constant production of WaF17.12-KT over time, after stimulation of toxin secretion in yeast cultures and reintroduction of the activated cells into the mosquito through the diet. Furthermore, the antimicrobial activity of WaF17.12-KT has been demonstrated in vitro against sensitive microbes, showing that strain WaF17.12 releases a functional toxin. The mosquito-associated yeast WaF17.12 thus possesses an antimicrobial activity, which makes this yeast worthy of further investigations, in view of its potential as an agent for the symbiotic control of malaria. PMID:24788884

  1. Delayed larval development in Anopheles mosquitoes deprived of Asaia bacterial symbionts

    PubMed Central

    2012-01-01

    Background In recent years, acetic acid bacteria have been shown to be frequently associated with insects, but knowledge on their biological role in the arthropod host is limited. The discovery that acetic acid bacteria of the genus Asaia are a main component of the microbiota of Anopheles stephensi makes this mosquito a useful model for studies on this novel group of symbionts. Here we present experimental results that provide a first evidence for a beneficial role of Asaia in An. stephensi. Results Larvae of An. stephensi at different stages were treated with rifampicin, an antibiotic effective on wild-type Asaia spp., and the effects on the larval development were evaluated. Larvae treated with the antibiotic showed a delay in the development and an asynchrony in the appearance of later instars. In larvae treated with rifampicin, but supplemented with a rifampicin-resistant mutant strain of Asaia, larval development was comparable to that of control larvae not exposed to the antibiotic. Analysis of the bacterial diversity of the three mosquito populations confirmed that the level of Asaia was strongly decreased in the antibiotic-treated larvae, since the symbiont was not detectable by PCR-DGGE (denaturing gradient gel electrophoresis), while Asaia was consistently found in insects supplemented with rifampicin plus the antibiotic-resistant mutant in the diet, and in those not exposed to the antibiotic. Conclusions The results here reported indicate that Asaia symbionts play a beneficial role in the normal development of An. stephensi larvae. PMID:22375964

  2. Site-specific genetic engineering of the Anopheles gambiae Y chromosome.

    PubMed

    Bernardini, Federica; Galizi, Roberto; Menichelli, Miriam; Papathanos, Philippos-Aris; Dritsou, Vicky; Marois, Eric; Crisanti, Andrea; Windbichler, Nikolai

    2014-05-27

    Despite its function in sex determination and its role in driving genome evolution, the Y chromosome remains poorly understood in most species. Y chromosomes are gene-poor, repeat-rich and largely heterochromatic and therefore represent a difficult target for genetic engineering. The Y chromosome of the human malaria vector Anopheles gambiae appears to be involved in sex determination although very little is known about both its structure and function. Here, we characterize a transgenic strain of this mosquito species, obtained by transposon-mediated integration of a transgene construct onto the Y chromosome. Using meganuclease-induced homologous repair we introduce a site-specific recombination signal onto the Y chromosome and show that the resulting docking line can be used for secondary integration. To demonstrate its utility, we study the activity of a germ-line-specific promoter when located on the Y chromosome. We also show that Y-linked fluorescent transgenes allow automated sex separation of this important vector species, providing the means to generate large single-sex populations. Our findings will aid studies of sex chromosome function and enable the development of male-exclusive genetic traits for vector control.

  3. Isolation of Bacillus sphaericus from Lombok Island, Indonesia, and Their Toxicity against Anopheles aconitus.

    PubMed

    Suryadi, Bambang Fajar; Yanuwiadi, Bagyo; Ardyati, Tri; Suharjono

    2015-01-01

    Malaria is endemic to Lombok Island, Indonesia. One approach to suppress malaria spread is to eliminate anopheline larvae in their habitat and the environmentally safe agent is bacteria, that is, Bacillus sphaericus. However, there is no information regarding local isolate of B. sphaericus that is toxic to mosquito larvae from Lombok. The aims of the study were to isolate B. sphaericus from soil in areas close to beach surrounding Lombok Island and to test their toxicity against 3rd instar Anopheles aconitus larvae. Soil samples were collected from 20 different sampling locations from Lombok Island and homogenized with sterile physiological salt solution. Suspension was heat-shocked at 80°C for 30 minutes and then spread onto antibiotic-supplemented NYSM solid medium. Colonies grown were characterized and subjected to initial toxicity test against anopheline larvae. Isolates with more than 50% killing percentage were subjected to bioassay testing against anopheline larvae. From 20 locations, 1 isolate showed mild toxicity (namely, isolate MNT) and 2 isolates showed high toxicity (namely, isolates SLG and TJL2) against An. aconitus. Those 3 isolates were potentially useful isolates, as they killed almost all larvae in 24 hours. The discovery of toxic indigenous isolates of B. sphaericus from Lombok Island opens opportunity to develop a biopesticide from local resources.

  4. Predicting Ancestral Segmentation Phenotypes from Drosophila to Anopheles Using In Silico Evolution

    PubMed Central

    Rothschild, Jeremy B.; Tsimiklis, Panagiotis; Siggia, Eric D.; François, Paul

    2016-01-01

    Molecular evolution is an established technique for inferring gene homology but regulatory DNA turns over so rapidly that inference of ancestral networks is often impossible. In silico evolution is used to compute the most parsimonious path in regulatory space for anterior-posterior patterning linking two Dipterian species. The expression pattern of gap genes has evolved between Drosophila (fly) and Anopheles (mosquito), yet one of their targets, eve, has remained invariant. Our model predicts that stripe 5 in fly disappears and a new posterior stripe is created in mosquito, thus eve stripe modules 3+7 and 4+6 in fly are homologous to 3+6 and 4+5 in mosquito. We can place Clogmia on this evolutionary pathway and it shares the mosquito homologies. To account for the evolution of the other pair-rule genes in the posterior we have to assume that the ancestral Dipterian utilized a dynamic method to phase those genes in relation to eve. PMID:27227405

  5. Interactive cost of Plasmodium infection and insecticide resistance in the malaria vector Anopheles gambiae.

    PubMed

    Alout, Haoues; Dabiré, Roch K; Djogbénou, Luc S; Abate, Luc; Corbel, Vincent; Chandre, Fabrice; Cohuet, Anna

    2016-07-19

    Insecticide resistance raises concerns for the control of vector-borne diseases. However, its impact on parasite transmission could be diverse when considering the ecological interactions between vector and parasite. Thus we investigated the fitness cost associated with insecticide resistance and Plasmodium falciparum infection as well as their interactive cost on Anopheles gambiae survival and fecundity. In absence of infection, we observed a cost on fecundity associated with insecticide resistance. However, survival was higher for mosquito bearing the kdr mutation and equal for those with the ace-1(R) mutation compared to their insecticide susceptible counterparts. Interestingly, Plasmodium infection reduced survival only in the insecticide resistant strains but not in the susceptible one and infection was associated with an increase in fecundity independently of the strain considered. This study provides evidence for a survival cost associated with infection by Plasmodium parasite only in mosquito selected for insecticide resistance. This suggests that the selection of insecticide resistance mutation may have disturbed the interaction between parasites and vectors, resulting in increased cost of infection. Considering the fitness cost as well as other ecological aspects of this natural mosquito-parasite combination is important to predict the epidemiological impact of insecticide resistance.

  6. Artificial activation of mature unfertilized eggs in the malaria vector mosquito, Anopheles stephensi (Diptera, Culicidae).

    PubMed

    Yamamoto, Daisuke S; Hatakeyama, Masatsugu; Matsuoka, Hiroyuki

    2013-08-01

    In the past decade, many transgenic lines of mosquitoes have been generated and analyzed, whereas the maintenance of a large number of transgenic lines requires a great deal of effort and cost. In vitro fertilization by an injection of cryopreserved sperm into eggs has been proven to be effective for the maintenance of strains in mammals. The technique of artificial egg activation is a prerequisite for the establishment of in vitro fertilization by sperm injection. We demonstrated that artificial egg activation is feasible in the malaria vector mosquito, Anopheles stephensi (Diptera, Culicidae). Nearly 100% of eggs dissected from virgin females immersed in distilled water darkened, similar to normally oviposited fertilized eggs. It was revealed by the cytological examination of chromosomes that meiotic arrest was relieved in these eggs approximately 20 min after incubation in water. Biochemical examinations revealed that MAPK (mitogen-activated protein kinase)/ERK (extracellular signal-regulated protein kinase) and MEK (MAPK/ERK kinase) were dephosphorylated similar to that in fertilized eggs. These results indicate that dissected unfertilized eggs were activated in distilled water and started development. Injection of distilled water into body cavity of the virgin blood-fed females also induced activation of a portion of eggs in the ovaries. The technique of artificial egg activation is expected to contribute to the success of in vitro fertilization in A. stephensi.

  7. Larvicidal effects of a neem (Azadirachta indica) oil formulation on the malaria vector Anopheles gambiae

    PubMed Central

    Okumu, Fredros O; Knols, Bart GJ; Fillinger, Ulrike

    2007-01-01

    Background Larviciding is a key strategy used in many vector control programmes around the world. Costs could be reduced if larvicides could be manufactured locally. The potential of natural products as larvicides against the main African malaria vector, Anopheles gambiae s.s was evaluated. Methods To assess the larvicidal efficacy of a neem (Azadirachta indica) oil formulation (azadirachtin content of 0.03% w/v) on An. gambiae s.s., larvae were exposed as third and fourth instars to a normal diet supplemented with the neem oil formulations in different concentrations. A control group of larvae was exposed to a corn oil formulation in similar concentrations. Results Neem oil had an LC50 value of 11 ppm after 8 days, which was nearly five times more toxic than the corn oil formulation. Adult emergence was inhibited by 50% at a concentration of 6 ppm. Significant reductions on growth indices and pupation, besides prolonged larval periods, were observed at neem oil concentrations above 8 ppm. The corn oil formulation, in contrast, produced no growth disruption within the tested range of concentrations. Conclusion Neem oil has good larvicidal properties for An. gambiae s.s. and suppresses successful adult emergence at very low concentrations. Considering the wide distribution and availability of this tree and its products along the East African coast, this may prove a readily available and cheap alternative to conventional larvicides. PMID:17519000

  8. Comparative Genome and Proteome Analysis of Anopheles gambiae and Drosophila melanogaster

    NASA Astrophysics Data System (ADS)

    Zdobnov, Evgeny M.; von Mering, Christian; Letunic, Ivica; Torrents, David; Suyama, Mikita; Copley, Richard R.; Christophides, George K.; Thomasova, Dana; Holt, Robert A.; Subramanian, G. Mani; Mueller, Hans-Michael; Dimopoulos, George; Law, John H.; Wells, Michael A.; Birney, Ewan; Charlab, Rosane; Halpern, Aaron L.; Kokoza, Elena; Kraft, Cheryl L.; Lai, Zhongwu; Lewis, Suzanna; Louis, Christos; Barillas-Mury, Carolina; Nusskern, Deborah; Rubin, Gerald M.; Salzberg, Steven L.; Sutton, Granger G.; Topalis, Pantelis; Wides, Ron; Wincker, Patrick; Yandell, Mark; Collins, Frank H.; Ribeiro, Jose; Gelbart, William M.; Kafatos, Fotis C.; Bork, Peer

    2002-10-01

    Comparison of the genomes and proteomes of the two diptera Anopheles gambiae and Drosophila melanogaster, which diverged about 250 million years ago, reveals considerable similarities. However, numerous differences are also observed; some of these must reflect the selection and subsequent adaptation associated with different ecologies and life strategies. Almost half of the genes in both genomes are interpreted as orthologs and show an average sequence identity of about 56%, which is slightly lower than that observed between the orthologs of the pufferfish and human (diverged about 450 million years ago). This indicates that these two insects diverged considerably faster than vertebrates. Aligned sequences reveal that orthologous genes have retained only half of their intron/exon structure, indicating that intron gains or losses have occurred at a rate of about one per gene per 125 million years. Chromosomal arms exhibit significant remnants of homology between the two species, although only 34% of the genes colocalize in small ``microsyntenic'' clusters, and major interarm transfers as well as intra-arm shuffling of gene order are detected.

  9. Aestivation of the African Malaria Mosquito, Anopheles gambiae in the Sahel

    PubMed Central

    Lehmann, Tovi; Dao, Adama; Yaro, Alpha Seydou; Adamou, Abdoulaye; Kassogue, Yaya; Diallo, Moussa; Sékou, Traoré; Coscaron-Arias, Cecilia

    2010-01-01

    The African malaria mosquito, Anopheles gambiae, inhabits diverse environments including dry savannas, where surface waters required for larval development are absent for 4–8 months per year. Under such conditions, An. gambiae virtually disappears. Whether populations survive the long dry season by aestivation (a dormant state promoting extended longevity during the summer) or are reestablished by migrants from distant locations where larval sites persist has remained an enigma for over 60 years. Resolving this question is important, because fragile dry season populations may be more susceptible to control. Here, we show unequivocally that An. gambiae aestivates based on a demographic study and a mark release–recapture experiment spanning the period from the end of one wet season to the beginning of the next. During the dry season, An. gambiae was barely detectable in Sahelian villages of Mali. Five days after the first rain, before a new generation of adults could be produced, mosquito abundance surged 10-fold, implying that most mosquitoes were concealed locally until the rain. Four days after the first rain, a marked female An. gambiae s.s. was recaptured. Initially captured, marked, and released at the end of the previous wet season, she has survived the 7-month-long dry season. These results provide evidence that An. gambiae persists throughout the dry season by aestivation and open new questions for mosquito and parasite research. Improved malaria control by targeting aestivating mosquitoes using existing or novel strategies may be possible. PMID:20810827

  10. Molecular characterization, biological forms and sporozoite rate of Anopheles stephensi in southern Iran

    PubMed Central

    Chavshin, Ali Reza; Oshaghi, Mohammad Ali; Vatandoost, Hasan; Hanafi-Bojd, Ahmad Ali; Raeisi, Ahmad; Nikpoor, Fatemeh

    2014-01-01

    Objective To identify the biological forms, sporozoite rate and molecular characterization of the Anopheles stephensi (An. stephensi) in Hormozgan and Sistan-Baluchistan provinces, the most important malarious areas in Iran. Methods Wild live An. stephensi samples were collected from different malarious areas in southern Iran. The biological forms were identified based on number of egg-ridges. Molecular characterization of biological forms was verified by analysis of the mitochondrial cytochrome oxidase subunit I and II (mtDNA-COI/COII). The Plasmodium infection was examined in the wild female specimens by species-specific nested–PCR method. Results Results showed that all three biological forms including mysorensis, intermediate and type are present in the study areas. Molecular investigations revealed no genetic variation between mtDNA COI/COII sequences of the biological forms and no Plasmodium parasites was detected in the collected mosquito samples. Conclusions Presence of three biological forms with identical sequences showed that the known biological forms belong to a single taxon and the various vectorial capacities reported for these forms are more likely corresponded to other epidemiological factors than to the morphotype of the populations. Lack of malaria parasite infection in An. stephensi, the most important vector of malaria, may be partly due to the success and achievement of ongoing active malaria control program in the region. PMID:24144130

  11. Innexin AGAP001476 is critical for mediating anti-Plasmodium responses in Anopheles mosquitoes.

    PubMed

    Li, Michelle W M; Wang, Jiuling; Zhao, Yang O; Fikrig, Erol

    2014-09-05

    The Toll and IMD pathways are known to be induced upon Plasmodium berghei and Plasmodium falciparum infection, respectively. It is unclear how Plasmodium or other pathogens in the blood meal and their invasion of the midgut epithelium would trigger the innate immune responses in immune cells, in particular hemocytes. Gap junctions, which can mediate both cell-to-cell and cell-to-extracellular communication, may participate in this signal transduction. This study examined whether innexins, gap junction proteins in insects, are involved in anti-Plasmodium responses in Anopheles gambiae. Inhibitor studies using carbenoxolone indicated that blocking innexons resulted in an increase in Plasmodium oocyst number and infection prevalence. This was accompanied by a decline in TEP1 levels in carbenoxolone-treated mosquitoes. Innexin AGAP001476 mRNA levels in midguts were induced during Plasmodium infection and a knockdown of AGAP001476, but not AGAP006241, caused an induction in oocyst number. Silencing AGAP001476 caused a concurrent increase in vitellogenin levels, a TEP1 inhibitor, in addition to a reduced level of TEP1-LRIM1-APL1C complex in hemolymph. Both vitellogenin and TEP1 are regulated by Cactus under the Toll pathway. Simultaneous knockdown of cactus and AGAP001476 failed to reverse the near refractoriness induced by the knockdown of cactus, suggesting that the AGAP001476-mediated anti-Plasmodium response is Cactus-dependent. These data demonstrate a critical role for innexin AGAP001476 in mediating innate immune responses against Plasmodium through Toll pathway in mosquitoes.

  12. Mosaic: a position-effect variegation eye-color mutant in the mosquito Anopheles gambiae.

    PubMed

    Benedict, M Q; McNitt, L M; Cornel, A J; Collins, F H

    2000-01-01

    The Mosaic (Mos) mutation, isolated in the F1 of 60Co-irradiated mosquitoes, confers variegated eye color to third and fourth instar larvae, pupae, and adults of the mosquito Anopheles gambiae. Mos is recessive in wild pink eye (p+) individuals, but is dominant and confers areas of wild-type pigment in mutant pink eye backgrounds. Mos is located 14.4 cM from pink eye on the X chromosome and is associated with a duplication of division 2B euchromatin that has been inserted into division 6 heterochromatin. Various combinations of Mos, pink eye alleles, and the autosomal mutation red eye were produced. In all cases, the darker pigmented regions of the eye in Mos individuals show the phenotypic interactions expected if the phenotype of those regions is due to expression of a p+ allele. Expression of Mos is suppressed by rearing larvae at 32 degrees C relative to 22 degrees C. All of these characteristics are consistent with Mos being a duplicated wild copy of the pink eye gene undergoing position-effect variegation.

  13. Gut microbes influence fitness and malaria transmission potential of Asian malaria vector Anopheles stephensi.

    PubMed

    Sharma, Anil; Dhayal, Devender; Singh, O P; Adak, T; Bhatnagar, Raj K

    2013-10-01

    The midgut of parasite transmitting vector, Anopheles stephensi is a physiologically dynamic ecological niche of resident microbes. The gut resident microbes of anisomorphic and physiologically variable male and female A. stephensi mosquitoes were different (Rani et al., 2009). To understand the possible interaction of gut microbes and mosquito host, we examined the contribution of the microbe community on the fitness of the adult mosquitoes and their ability to permit development of the malaria parasite. A. stephensi mosquitoes were fed with antibiotic to sterilize their gut to study longevity, blood meal digestion, egg laying and maturation capacity, and consequently ability to support malaria parasite development. The sterilization of gut imparted reduction in longevity by a median of 5 days in male and 2 days in female mosquitoes. Similarly, the sterilization also diminished the reproductive potential probably due to increased rate of the resorption of follicles in ovaries coupled with abated blood meal digestion in gut-sterilized females. Additionally, gut sterilization also led to increased susceptibility to oocyst development upon feeding on malaria infected blood. The susceptibility to malaria parasite introduced upon gut sterilization of A. stephensi was restored completely upon re-colonization of gut by native microbes. The information provided in the study provides insights into the role of the gut-resident microbial community in various life events of the mosquito that may be used to develop alternate malaria control strategies, such as paratransgenesis.

  14. Larvicidal Activity of Essential Oils of Apiaceae Plants against Malaria Vector, Anopheles stephensi

    PubMed Central

    Sedaghat, MM; Dehkordi, A Sanei; Abai, MR; Khanavi, M; Mohtarami, F; Abadi, Y Salim; Rafi, F; Vatandoost, H

    2011-01-01

    Background: Plant extracts and oils may act as alternatives to conventional pesticides for malaria vector control. The aim of this study was to evaluate the larvicidal activity of essential oils of three plants of Apiaceae family against Anopheles stephensi, the main malaria vector in Iran. Methods: Essential oils from Heracleum persicum, Foeniculum vulgare and Coriandrum sativum seeds were hydro distillated, then their larvicidal activity were evaluated against laboratory-reared larvae of An. stephensi according to standard method of WHO. After susceptibility test, results were analysis using Probit program. Results: Essential oils were separated from H. persicum, F. vulgare and C. sativum plants and their larvicidal activities were tested. Result of this study showed that F. vulgare oil was the most effective against An. stephensi with LC50 and LC90 values of 20.10 and 44.51 ppm, respectively. Conclusion: All three plants essential oil can serve as a natural larvicide against An. stephensi. F. vulgare oil exhibited more larvicidal properties. PMID:22808418

  15. Larvicidal Activity of Centaurea bruguierana ssp. belangerana Against Anopheles stephensi Larvae

    PubMed Central

    Khanavi, Mahnaz; Rajabi, Afsaneh; Behzad, Masoud; Hadjiakhoondi, Abbas; Vatandoost, Hassan; Abaee, Mohammad Reza

    2011-01-01

    In this study, the total 80% of MeOH extract and also petroleum ether, CHCl3, EtOAc, n-BuOH, and the remaining MeOH fractions obtained by solvent-solvent fractionation of the whole flowering samples of Centaurea bruguierana (DC.) Hand.-Mzt. ssp. belangerana (DC.) Bornm. (Asteraceae), namely “Baad-Avard”, collected from Borazjan in Bushehr Province (Bushehr, Iran) were investigated for larvicidal activity against malaria vector, Anopheles stephensi Liston, according to WHO methods. The mortality rate of total extract and petroleum ether fraction in concentration of 40 ppm were 28% and 86% respectively and the other fractions were inactive. The probit regression analysis for the dose-response to petroleum ether fraction treatment of larvae exhibited the LC50 and LC90 values of 15.7 ppm and 48.3 ppm, respectively. As results showed, the larvicidal activity of the petroleum ether fraction would be due to the nonpolar compounds in the plant which further isolation and purification would obtain the more active compounds in lower concentrations useful for preparation of biological insecticides. PMID:24250419

  16. Infertility resulting from transgenic I-PpoI male Anopheles gambiae in large cage trials

    PubMed Central

    Klein, T A; Windbichler, N; Deredec, A; Burt, A; Benedict, M Q

    2012-01-01

    Objectives Anopheles gambiae is the primary vector of malaria in sub-Saharan Africa and is a potential target of genetic control programs. We determined the capacity of male A. gambiae created by germline transformation to introduce infertility into stable age-distribution populations. We also determined effects of the transgenes on life history. Methods Stable age-distribution populations of A. gambiae mosquitoes were established in large indoor cages. Male mosquitoes carrying an I-PpoI homing endonuclease gene were introduced at ×5 and ×10 release rates where they competed with target male mosquitoes for matings. Similar trials were conducted in small cages with an additional ×1 release level. Results Infertility was successfully introduced into all target populations. In supporting experiments, complete female infertility was observed in all strains and species of the A. gambiae complex to which transgenic males were mated. Life history experiments demonstrated that reductions in I-PpoI male vigor exist in the form of reduced adult male emergence, longevity and competitiveness. Discussion A. gambiae I-PpoI males are capable of introducing high levels of infertility in target populations in indoor cage trials. This was accomplished despite losses of vigor resulting from the HEG transgene. These results motivate further trials of sexually I-PpoI A. gambiae in outdoor cage and field trials. PMID:22595271

  17. Induced immunity against the mosquito Anopheles stephensi Liston (Diptera: Culicidae): effects on mosquito survival and fecundity.

    PubMed

    Almeida, A P; Billingsley, P F

    1998-11-01

    Mice were immunised three to five times with extracts of Anopheles stephensi heads, midguts, ovaries or fat bodies. At each immunisation the effects of feeding An. stephensi on the mice was determined, and changes in mosquito longevity and fecundity examined as the immune response developed. Although variability was common between control cages, significant and consistent reductions in mosquito longevity were observed when midguts were used as immunogens. Other extracts caused transient reductions in mortality. Fecundity was reduced significantly in mosquitoes fed upon mice immunised with each extract in at least one experiment. Mosquitoes fed upon fat-body-immunised mice showed delayed egg-laying as well as overall reduction in fecundity. The results confirm the feasibility of targeting mosquito antigens for novel vaccine development, but the "shotgun" approach used probably fails to successfully hit a suitable target antigen with any consistency. The natural variation in mosquito mortality can be countered by rigorous statistical analysis which can identify subtle effects in a very "noisy" experimental system. The midgut is the obvious target organ for anti-mosquito vaccine development and future work will focus on targeting components of this tissue for further immunisations.

  18. Wide cross-reactivity between Anopheles gambiae and Anopheles funestus SG6 salivary proteins supports exploitation of gSG6 as a marker of human exposure to major malaria vectors in tropical Africa

    PubMed Central

    2011-01-01

    Background The Anopheles gambiae gSG6 is an anopheline-specific salivary protein which helps female mosquitoes to efficiently feed on blood. Besides its role in haematophagy, gSG6 is immunogenic and elicits in exposed individuals an IgG response, which may be used as indicator of exposure to the main African malaria vector A. gambiae. However, malaria transmission in tropical Africa is sustained by three main vectors (A. gambiae, Anopheles arabiensis and Anopheles funestus) and a general marker, reflecting exposure to at least these three species, would be especially valuable. The SG6 protein is highly conserved within the A. gambiae species complex whereas the A. funestus homologue, fSG6, is more divergent (80% identity with gSG6). The aim of this study was to evaluate cross-reactivity of human sera to gSG6 and fSG6. Methods The A. funestus SG6 protein was expressed/purified and the humoral response to gSG6, fSG6 and a combination of the two antigens was compared in a population from a malaria hyperendemic area of Burkina Faso where both vectors were present, although with a large A. gambiae prevalence (>75%). Sera collected at the beginning and at the end of the high transmission/rainy season, as well as during the following low transmission/dry season, were analysed. Results According to previous observations, both anti-SG6 IgG level and prevalence decreased during the low transmission/dry season and showed a typical age-dependent pattern. No significant difference in the response to the two antigens was found, although their combined use yielded in most cases higher IgG level. Conclusions Comparative analysis of gSG6 and fSG6 immunogenicity to humans suggests the occurrence of a wide cross-reactivity, even though the two proteins carry species-specific epitopes. This study supports the use of gSG6 as reliable indicator of exposure to the three main African malaria vectors, a marker which may be useful to monitor malaria transmission and evaluate vector control

  19. Spatial distribution, blood feeding pattern, and role of Anopheles funestus complex in malaria transmission in central Kenya.

    PubMed

    Muturi, Ephantus J; Kamau, Luna; Jacob, Benjamin G; Muriu, Simon; Mbogo, Charles M; Shililu, Josephat; Githure, John; Novak, Robert J

    2009-10-01

    Studies were conducted to determine the role of sibling species of Anopheles funestus complex in malaria transmission in three agro-ecosystems in central Kenya. Mosquitoes were sampled indoors and outdoors, and rDNA PCR was successfully used to identify 340 specimens. Anopheles parensis (91.8%), A. funestus (6.8%), and Anopheles leesoni (1.5%) were the three sibling species identified. A. parensis was the dominant species at all study sites, while 22 of 23 A. funestus were collected in the non-irrigated study site. None of the 362 specimens tested was positive for Plasmodium falciparum circumsporozoite proteins by enzyme-linked immunosorbent assay. The most common blood-meal sources (mixed blood meals included) for A. parensis were goat (54.0%), human (47.6%), and bovine (39.7%), while the few A. funestus s.s. samples had fed mostly on humans. The human blood index (HBI) for A. parensis (mixed blood meals included) in the non-irrigated agro-ecosystem was 0.93 and significantly higher than 0.33 in planned rice agro-ecosystem. The few samples of A. funestus s.s. and A. funestus s.l. also showed a trend of higher HBI in the non-irrigated agro-ecosystem. We conclude that agricultural practices have significant influence on distribution and blood feeding behavior of A. funestus complex. Although none of the species was implicated with malaria transmission, these results may partly explain why non-irrigated agro-ecosystems are associated with higher risk of malaria transmission by this species compared to irrigated agro-ecosystems.

  20. Biology, distribution and control of Anopheles (Cellia) minimus in the context of malaria transmission in northeastern India.

    PubMed

    Dev, Vas; Manguin, Sylvie

    2016-11-15

    Among six dominant mosquito vector species involved in malaria transmission in India, Anopheles minimus is a major species in northeast India and held responsible for focal disease outbreaks characterized by high-rise of Plasmodium falciparum infections and attributable death cases. It has been now genetically characterized that among the three-member species of the Minimus Complex spread in Asia, An. minimus (former species A) is prevalent in India including northeastern states and east-central state of Odisha. It is recorded in all seasons and accounts for perennial transmission evidenced by records of sporozoite infections. This species is highly anthropophilic, and largely endophilic and endophagic, recorded breeding throughout the year in slow flowing seepage water streams. The populations of An. minimus in India are reported to be highly diverse indicating population expansion with obvious implications for judicious application of vector control interventions. Given the rapid ecological changes due to deforestation, population migration and expansion and developmental activities, there is scope for further research on the existence of potential additional sibling species within the An. minimus complex and bionomics studies on a large geographical scale for species sanitation. For control of vector populations, DDT continues to be applied on account of retaining susceptibility status even after decades of residual spraying. Anopheles minimus is a highly adaptive species and requires continuous and sustained efforts for its effective control to check transmission and spread of drug-resistant malaria. Anopheles minimus populations are reportedly diminishing in northeastern India whereas it has staged comeback in east-central State of Odisha after decades of disappearance with its eco-biological characteristics intact. It is the high time to siege the opportunity for strengthening interventions against this species for its population diminution to sub

  1. PCR identification of five species from the Anopheles maculipennis complex (Diptera: Culicidae) in North-Eastern Romania.

    PubMed

    Ivanescu, Maria-Larisa; Acatrinei, Dumitru; Pavel, Ionuţ; Sulesco, Tatiana; Miron, Liviu

    2015-06-01

    The members of the Anopheles maculipennis complex have been incriminated for the transmission of the malaria in Europe, which was endemic until the middle of the century. The global warming and the intensification of the intercontinental travel constitute a risk of the re-emergence of the malaria in Europe, given the presence of the Anopheles vectors. The study has attempted the identification by using the PCR (Polymerase Chain Reaction) of the members of the Anopheles maculipennis complex from the North-eastern area of Romania from the city of Iaşi. In total there have been identified by using the PCR amplifying the ITS2 sequence of the ribosomal DNA, 217 specimens belonging to the complex of A. maculipennis among which: 58 A. atroparvus, 18 A. melanoon, 2 A. labranchiae, 52 A. maculipennis and 87 A. messeae. The ITS2 sequences of the ribosomal DNA have been compared to those of the species belonging to the A. maculipennis available in GenBank. The Species A. labranchiae is reported for the first time in Romania, being identified in the larval stage IV. The adaptation of a new species to the climatic conditions present in the North-eastern Romania, confirms the phenomenon of global warming and also the intensification of the travelling. As a result of the analysis of the A. labranchiae sequence, this one corresponds to the extent of 96% to the species from Italy, registered in GenBank, given the fact that a high number of the inhabitants of the municipality of Iaşi are working in this country.

  2. Silencing of Anopheles stephensi Heme Peroxidase HPX15 Activates Diverse Immune Pathways to Regulate the Growth of Midgut Bacteria

    PubMed Central

    Kajla, Mithilesh; Choudhury, Tania P.; Kakani, Parik; Gupta, Kuldeep; Dhawan, Rini; Gupta, Lalita; Kumar, Sanjeev

    2016-01-01

    Anopheles mosquito midgut harbors a diverse group of endogenous bacteria that grow extensively after the blood feeding and help in food digestion and nutrition in many ways. Although, the growth of endogenous bacteria is regulated by various factors, however, the robust antibacterial immune reactions are generally suppressed in this body compartment by a heme peroxidase HPX15 crosslinked mucins barrier. This barrier is formed on the luminal side of the midgut and blocks the direct interactions and recognition of bacteria or their elicitors by the immune reactive midgut epithelium. We hypothesized that in the absence of HPX15, an increased load of exogenous bacteria will enormously induce the mosquito midgut immunity and this situation in turn, can easily regulate mosquito-pathogen interactions. In this study, we found that the blood feeding induced AsHPX15 gene in Anopheles stephensi midgut and promoted the growth of endogenous as well as exogenous fed bacteria. In addition, the mosquito midgut also efficiently regulated the number of these bacteria through the induction of classical Toll and Imd immune pathways. In case of AsHPX15 silenced midguts, the growth of midgut bacteria was largely reduced through the induction of nitric oxide synthase (NOS) gene, a downstream effector molecule of the JAK/STAT pathway. Interestingly, no significant induction of the classical immune pathways was observed in these midguts. Importantly, the NOS is a well known negative regulator of Plasmodium development, thus, we proposed that the induction of diverged immune pathways in the absence of HPX15 mediated midgut barrier might be one of the strategies to manipulate the vectorial capacity of Anopheles mosquito. PMID:27630620

  3. Single concentration tests show synergism among Bacillus thuringiensis subsp. israelensis toxins against the malaria vector mosquito Anopheles albimanus.

    PubMed

    Fernández-Luna, María Teresa; Tabashnik, Bruce E; Lanz-Mendoza, Humberto; Bravo, Alejandra; Soberón, Mario; Miranda-Ríos, Juan

    2010-07-01

    Bioassays of insecticidal proteins from Bacillus thuringiensis subsp. israelensis with larvae of the malaria vector mosquito Anopheles albimanus showed that the cytolytic protein Cyt1Aa was not toxic alone, but it increased the toxicity of the crystalline proteins Cry4Ba and Cry11Aa. Synergism also occurred between Cry4Ba and Cry11Aa toxins. Whereas many previous analyses of synergism have been based on a series of toxin concentrations leading to comparisons between expected and observed values for the concentration killing 50% of insects tested (LC(50)), we describe and apply a method here that enables testing for synergism based on single concentrations of toxins.

  4. BIONOMICS AND ECOLOGY OF ANOPHELES LITORALIS ON BONGAO ISLAND, TAWI-TAWI PROVINCE, PHILIPPINES: IMPLICATIONS FOR VECTOR CONTROL.

    PubMed

    Salazar, Ferdinand V; Torno, Majhalia M; Galang, Cristina; Baquilod, Mario; Bangs, Michael J

    2015-05-01

    Entomological surveys were conducted to identify Anopheles malaria vector species, their feeding and resting behaviors, and characterization of larval habitats on Bongao Island, Tawi-tawi Province, in July and November, 2007. Survey parameters included all-evening human-landing collections (HLC), evening buffalo-baited trap (BBT) collections, daytime indoor and outdoor adult resting collections, adult female age-grading, identification of natural Plasmodium infections in mosquitoes, larval habitat identification and physical/biological characterization, and adult insecticide susceptibility assays. Both surveys revealed the predominant and putative malaria vector species on Bongao Island is Anopheles litoralis. Anophelesflavirostris was collected on only one occasion. The HLC during the July survey produced approximately 4 mosquitoes/human/night (mhn). The November survey yielded 1.27 mhn due, in part, to inclement weather conditions during time of sampling. Anopheles litoralis host seeking behavior occurred throughout the evening (06:00 PM - 06:00 AM) with peak biting between 10:00 PM and 04:00 AM. This species exhibited stronger zoophilic behavior based on comparison of HLC and BBT data. HLC showed a slightly greater exophagic (outdoor) behavior (1.4:1 ratio). During the July collection, an older adult population was present (75% parous) compared to the lower numbers of An. litoralis dissected in November (25% parous). Albeit a small sample size (n=19), 10.5% of An. litoralis dissected contained midgut oocysts of Plasmodium. Daytime adult resting harborages included biotic and abiotic sites in and around partially shaded, brackish water habitats where immature stages were common. Anopheles litoralis was found susceptible to pirimiphos-methyl and four different synthetic pyrethroids. This survey provides further epidemiological evidence of the importance of An. litoralis in malaria transmission on Bongao Island, and presumably throughout much of the Sulu

  5. Anopheles larval abundance and diversity in three rice agro-village complexes Mwea irrigation scheme, central Kenya

    PubMed Central

    2010-01-01

    Background The diversity and abundance of Anopheles larvae has significant influence on the resulting adult mosquito population and hence the dynamics of malaria transmission. Studies were conducted to examine larval habitat dynamics and ecological factors affecting survivorship of aquatic stages of malaria vectors in three agro-ecological settings in Mwea, Kenya. Methods Three villages were selected based on rice husbandry and water management practices. Aquatic habitats in the 3 villages representing planned rice cultivation (Mbui Njeru), unplanned rice cultivation (Kiamachiri) and non-irrigated (Murinduko) agro-ecosystems were sampled every 2 weeks to generate stage-specific estimates of mosquito larval densities, relative abundance and diversity. Records of distance to the nearest homestead, vegetation coverage, surface debris, turbidity, habitat stability, habitat type, rice growth stage, number of rice tillers and percent Azolla cover were taken for each habitat. Results Captures of early, late instars and pupae accounted for 78.2%, 10.9% and 10.8% of the total Anopheles immatures sampled (n = 29,252), respectively. There were significant differences in larval abundance between 3 agro-ecosystems. The village with 'planned' rice cultivation had relatively lower Anopheles larval densities compared to the villages where 'unplanned' or non-irrigated. Similarly, species composition and richness was higher in the two villages with either 'unplanned' or limited rice cultivation, an indication of the importance of land use patterns on diversity of larval habitat types. Rice fields and associated canals were the most productive habitat types while water pools and puddles were important for short periods during the rainy season. Multiple logistic regression analysis showed that presence of other invertebrates, percentage Azolla cover, distance to nearest homestead, depth and water turbidity were the best predictors for Anopheles mosquito larval abundance. Conclusion

  6. 16S rRNA gene sequences from bacteria associated with adult Anopheles darlingi (Diptera: Culicidae) mosquitoes.

    PubMed

    Terenius, Olle; de Oliveira, Caroline Dantas; Pinheiro, Waleria Dasso; Tadei, Wanderli Pedro; James, Anthony Amade; Marinotti, Osvaldo

    2008-01-01

    The microbial flora associated with Anopheles darlingi Root (Diptera: Culicidae), a major Neotropical malaria vector, was investigated for the development of a paratransgenesis-based approach to control malaria transmission in Brazil. Female mosquitoes were collected using human land catches and captured insects provided a bloodmeal. The controlled blood feeding resulted in increased detection of mosquito bacterial population because it was possible to retrieve bacterial DNA from all blood-fed mosquitoes. The 16S sequences of bacteria recovered, include some closely related to those found in other vector mosquitoes, including Aeromonas, Pantoea and Pseudomonas species.

  7. Comparative use of bendiocarb and DDT to control Anopheles pseudopunctipennis in a malarious area of Mexico.

    PubMed

    Loyola, E G; Vaca, M A; Bown, D N; Pérez, E; Rodriguez, M H

    1991-04-01

    The state of Sinaloa has one of the highest and most persistent malaria transmission levels in Mexico. Due to this situation, with resistance of the vector Anopheles pseudopunctipennis Theobald to DDT, the carbamate insecticide bendiocarb was evaluated as an alternative to DDT for residual house-spraying in village-scale trials during 1985-87. Application rates of the active ingredient per square metre of sprayable surface (ai/m2) were 0.4 g bendiocarb 80% wettable powder (80WP) and 2 g DDT 75% WP. Both insecticides failed to control mosquito populations. Human-bait mosquito densities were not altered as a result of insecticide spraying and human-bait collected mosquito mortality rates were low, suggesting little pre-biting insecticide contact due to avoidance or insufficient resting time indoors. Lower densities of indoor-resting mosquitoes were observed with DDT as opposed to bendiocarb treated houses. Anopheline mortality was higher (98-100%) when exposed for 1 h to 1% bendiocarb in standard WHO susceptibility tests and wall bioassays. Mortality-rates of 15-48% due to 1 h exposure to 4% DDT indicated that this insecticide may continue to be partially effective. House curtain and mark-recapture mosquito studies indicated that DDT produced higher excito-repellency than bendiocarb, as reflected by more mosquito landings but lower feeding rates, shorter resting period and earlier exit time from DDT sprayed houses. In the absence of insecticide, more than 50% of blood-fed An.pseudopunctipennis females exited from houses within 2-4 h of release, showing exophilic behaviour. The outdoor/indoor density ratio indicated that the majority were exophagic. These behavioural characteristics limit the usefulness of any residual insecticide against An.pseudopunctipennis.

  8. Landscape Movements of Anopheles gambiae Malaria Vector Mosquitoes in Rural Gambia

    PubMed Central

    Thomas, Christopher J.; Cross, Dónall E.; Bøgh, Claus

    2013-01-01

    Background For malaria control in Africa it is crucial to characterise the dispersal of its most efficient vector, Anopheles gambiae, in order to target interventions and assess their impact spatially. Our study is, we believe, the first to present a statistical model of dispersal probability against distance from breeding habitat to human settlements for this important disease vector. Methods/Principal Findings We undertook post-hoc analyses of mosquito catches made in The Gambia to derive statistical dispersal functions for An. gambiae sensu lato collected in 48 villages at varying distances to alluvial larval habitat along the River Gambia. The proportion dispersing declined exponentially with distance, and we estimated that 90% of movements were within 1.7 km. Although a ‘heavy-tailed’ distribution is considered biologically more plausible due to active dispersal by mosquitoes seeking blood meals, there was no statistical basis for choosing it over a negative exponential distribution. Using a simple random walk model with daily survival and movements previously recorded in Burkina Faso, we were able to reproduce the dispersal probabilities observed in The Gambia. Conclusions/Significance Our results provide an important quantification of the probability of An. gambiae s.l. dispersal in a rural African setting typical of many parts of the continent. However, dispersal will be landscape specific and in order to generalise to other spatial configurations of habitat and hosts it will be necessary to produce tractable models of mosquito movements for operational use. We show that simple random walk models have potential. Consequently, there is a pressing need for new empirical studies of An. gambiae survival and movements in different settings to drive this development. PMID:23874719

  9. Unbiased Characterization of Anopheles Mosquito Blood Meals by Targeted High-Throughput Sequencing

    PubMed Central

    Logue, Kyle; Keven, John Bosco; Cannon, Matthew V.; Reimer, Lisa; Siba, Peter; Walker, Edward D.; Zimmerman, Peter A.; Serre, David

    2016-01-01

    Understanding mosquito host choice is important for assessing vector competence or identifying disease reservoirs. Unfortunately, the availability of an unbiased method for comprehensively evaluating the composition of insect blood meals is very limited, as most current molecular assays only test for the presence of a few pre-selected species. These approaches also have limited ability to identify the presence of multiple mammalian hosts in a single blood meal. Here, we describe a novel high-throughput sequencing method that enables analysis of 96 mosquitoes simultaneously and provides a comprehensive and quantitative perspective on the composition of each blood meal. We validated in silico that universal primers targeting the mammalian mitochondrial 16S ribosomal RNA genes (16S rRNA) should amplify more than 95% of the mammalian 16S rRNA sequences present in the NCBI nucleotide database. We applied this method to 442 female Anopheles punctulatus s. l. mosquitoes collected in Papua New Guinea (PNG). While human (52.9%), dog (15.8%) and pig (29.2%) were the most common hosts identified in our study, we also detected DNA from mice, one marsupial species and two bat species. Our analyses also revealed that 16.3% of the mosquitoes fed on more than one host. Analysis of the human mitochondrial hypervariable region I in 102 human blood meals showed that 5 (4.9%) of the mosquitoes unambiguously fed on more than one person. Overall, analysis of PNG mosquitoes illustrates the potential of this approach to identify unsuspected hosts and characterize mixed blood meals, and shows how this approach can be adapted to evaluate inter-individual variations among human blood meals. Furthermore, this approach can be applied to any disease-transmitting arthropod and can be easily customized to investigate non-mammalian host sources. PMID:26963245

  10. A novel biopesticide PONNEEM to control human vector mosquitoes Anopheles stephensi L. and Culex quinquefasciatus Say.

    PubMed

    Maheswaran, Rajan; Ignacimuthu, Savarimuthu

    2015-09-01

    Organophosphate pesticides are widely used in vector mosquito management and agricultural pest management. These chemicals enter into natural water bodies and soil and cause hazards to the environment. The objective of this study was to prepare a natural pesticide which will not harm the environment and yet control vector mosquitoes. PONNEEM, a novel biopesticide, patented and prepared from the oils of Azadirachta indica and Pongamia glabra, was tested against Anopheles stephensi and Culex quinquefasciatus. One hundred percent larvicidal and ovicidal activities were observed at 0.1-ppm concentration of PONNEEM against the two mosquito species under laboratory and sunlight conditions up to 12 months from the date of manufacture. Very high oviposition reduction of 26.46 and 32.16 % is also recorded. Reductions in α-esterase level (0.0818 ± 0.340 and 0.2188 ± 0.003), β-esterase level (0.0866 ± 0.026 and 0.0398 ± 0.010 μg naphthol produced/min/mg larval protein), glutathione S-transferase enzyme (14.2571 ± 0.51 and 15.3326 ± 0.51 μmol/min/mg larval protein) and total protein levels (0.0390 ± 0.008 and 0.1975 ± 0.029 mg/individual larva in treated groups of A. stephensi and C. quinquefasciatus at 0.1-ppm concentration, respectively. The non-target organisms such as Gambusia affinis and Diplonychus indicus were not affected. Biopesticides are good alternatives to synthetic pesticides. PONNEEM can be effectively used for the management of human vector mosquitoes. Since it has a biodegradable nature and does not alter the environmental condition of water and soil.

  11. Larvicidal and repellent potential of Moringa oleifera against malarial vector, Anopheles stephensi Liston (Insecta: Diptera: Culicidae)

    PubMed Central

    Prabhu, K; Murugan, K; Nareshkumar, A; Ramasubramanian, N; Bragadeeswaran, S

    2011-01-01

    Objective To evaluate the larvicidal and pupicidal potential of the methanolic extracts from Moringa oleifera (M. oleifera) plant seeds against malarial vector Anopheles stephensi (A. stephensi) mosquitoes at different concentrations (20, 40, 60, 80 and 100 ppm). Methods M. oleifera was collected from the area of around Bharathiar University, Coimbatore. The dried plant materials were powdered by an electrical blender. From each sample, 100 g of the plant material were extracted with 300 mL of methanol for 8 h in a Soxhlet apparatus. The extracts were evaporated to dryness in rotary vacuum evaporator to yield 122 mg and 110 mg of dark greenish material (residue) from Arcang amara and Ocimum basilicum, respectively. One gram of the each plant residue was dissolved separately in 100 mL of acetone (stock solution) from which different concentrations, i.e., 20, 40, 60, 80 and 100 ppm were prepared. Results Larvicidal activity of M. oleifera exhibited in the first to fourth instar larvae of the A. stephensi, and the LC50 and LC90 values were 57.79 ppm and 125.93 ppm for the first instar, 63.90 ppm and 133.07 ppm for the second instar, 72.45 ppm and 139.82 ppm for the third instar, 78.93 ppm and 143.20 ppm for the fourth instar, respectively. During the pupal stage the methanolic extract of M. oleifera showed that the LC50 and LC90 values were 67.77 ppm and 141.00 ppm, respectively. Conclusions The present study indicates that the phytochemicals derived from M. oleifera seeds extracts are effective mosquito vector control agents and the plant extracts may be used for further integrated pest management programs. PMID:23569741

  12. Discriminative feeding behaviour of Anopheles gambiae s.s. on endemic plants in western Kenya

    PubMed Central

    Manda, H.; Gouagna, L. C.; Nyandat, E.; Kabiru, E. W.; Jackson, R. R.; Foster, W. A.; Githure, J. I.; Beier, J. C.; Hassanali, A.

    2009-01-01

    Anopheles gambiae Giles s.s. (Diptera: Culicidae) is known to feed on plant sugars, but this is the first experimental study to consider whether it discriminates between plant species. Thirteen perennial plant species were selected on the basis of their local availability within the vicinity of human dwellings and larval habitats of An. gambiae s.s. in western Kenya. Groups of 100 or 200 mosquitoes were released into cages either with a cutting of one plant type at a time (single-plant assay) or with cuttings of all 13 plants simultaneously (choice assay), respectively, and left overnight. In the choice assay, direct observations of the percentages of mosquitoes perching or feeding on each plant were recorded over four 1-h periods each night. For both types of assay, mosquitoes were recaptured and the percentage that had fed on plants was assessed by testing them individually for the presence of fructose. To identify which plants the choice-assay mosquitoes had fed on, gas chromatography (GC) profiles of samples of mosquito homogenates were compared with GC profiles of extracts from relevant parts of each plant. Four of the plants that were observed to have been fed on most frequently in the choice assay (Parthenium hysterophorus L., Tecoma stans L., Ricinus communis L., and Senna didymobotrya Fresen) were also shown to have been ingested most often by mosquitoes in both types of assay, suggesting that An. gambiae is differentially responsive to this range of plants, regardless of whether the plants were presented singly or mixed together. Significantly more females than males fed on plants, with the exception of P. hysterophorus L., one of the plants most frequently fed on. For most plant species (ten of 13), GC profiles indicated that An. gambiae obtained sugars primarily from flowers. The exceptions were P. hysterophorus L., Lantana camara L. and R. communis L., on which An. gambiae fed more often from leaves and stems than from flowers. PMID:17373953

  13. Salivary gland proteome of the human malaria vector, Anopheles campestris-like (Diptera: Culicidae).

    PubMed

    Sor-Suwan, Sriwatapron; Jariyapan, Narissara; Roytrakul, Sittiruk; Paemanee, Atchara; Saeung, Atiporn; Thongsahuan, Sorawat; Phattanawiboon, Benjarat; Bates, Paul A; Poovorawan, Yong; Choochote, Wej

    2013-03-01

    Anopheles campestris-like is proven to be a high-potential vector of Plasmodium vivax in Thailand. In this study, A. campestris-like salivary gland proteins were determined and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), two-dimensional gel electrophoresis, and nano-liquid chromatography-mass spectrometry. The total amount of salivary gland proteins in the mosquitoes aged 3-5 days was approximately 0.1 ± 0.05 μg/male and 1.38 ± 0.01 μg/female. SDS-PAGE analysis revealed at least 12 major proteins found in the female salivary glands and each morphological region of the female glands contained different major proteins. Two-dimensional gel electrophoresis showed approximately 20 major and several minor protein spots displaying relative molecular masses from 10 to 72 kDa with electric points ranging from 3.9 to 10. At least 15 glycoproteins were detected in the female glands. Similar electrophoretic protein profiles were detected comparing the male and proximal-lateral lobes of the female glands, suggesting that these lobes are responsible for sugar feeding. Blood-feeding proteins, i.e., putative 5'-nucleotidase/apyrase, anti-platelet protein, long-form D7 salivary protein, D7-related 1 protein, and gSG6, were detected in the distal-lateral lobes (DL) and/or medial lobes (ML) of the female glands. The major spots related to housekeeping proteins from other arthropod species including Culex quinquefasciatus serine/threonine-protein kinase rio3 expressed in both male and female glands, Ixodes scapularis putative sil1 expressed in DL and ML, and I. scapularis putative cyclophilin A expressed in DL. These results provide information for further study on the salivary gland proteins of A. campestris-like that are involved in hematophagy and disease transmission.

  14. Elizabethkingia anophelis sp. nov., isolated from the midgut of the mosquito Anopheles gambiae.

    PubMed

    Kämpfer, Peter; Matthews, Holly; Glaeser, Stefanie P; Martin, Karin; Lodders, Nicole; Faye, Ingrid

    2011-11-01

    The taxonomic position, growth characteristics and antibiotic resistance properties of a slightly yellow-pigmented bacterial strain, designated R26(T), isolated from the midgut of the mosquito Anopheles gambiae, were studied. The isolate produced rod-shaped cells, which stained Gram-negative. The bacterium had two growth optima at 30-31 °C and 37 °C. Strain R26(T) demonstrated natural antibiotic resistance to ampicillin, chloramphenicol, kanamycin, streptomycin and tetracycline. 16S rRNA gene sequence analysis revealed that the isolate showed 98.6 % sequence similarity to that of Elizabethkingia meningoseptica ATCC 13253(T) and 98.2 % similarity to that of Elizabethkingia miricola GTC 862(T). The major fatty acids of strain R26(T) were iso-C(15 : 0), iso-C(17 : 0) 3-OH and summed feature 4 (iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c/t). Strain R26(T) contained only menaquinone MK-6 and showed a complex polar lipid profile consisting of diphosphatidylglycerol, phosphatidylinositol, an unknown phospholipid and unknown polar lipids and glycolipids. DNA-DNA hybridization experiments with E. meningoseptica CCUG 214(T) ( = ATCC 13253(T)) and E. miricola KCTC 12492(T) ( = GTC 862(T)) gave relatedness values of 34.5 % (reciprocal 41.5 %) and 35.0 % (reciprocal 25.7 %), respectively. DNA-DNA hybridization results and some differentiating biochemical properties indicate that strain R26(T) represents a novel species, for which the name Elizabethkingia anophelis sp. nov. is proposed. The type strain is R26(T) ( = CCUG 60038(T) = CCM 7804(T)).

  15. Importance of algal biomass to growth and development of Anopheles gambiae larvae.

    PubMed

    Kaufman, Michael G; Wanja, Elizabeth; Maknojia, Shahnaz; Bayoh, M Nabie; Vulule, John M; Walker, Edward D

    2006-07-01

    We conducted experiments to investigate the importance of algal food resources for larval growth and adult emergence of Anopheles gambiae Giles s.s. in simulated larval habitats in Kenya, and in greenhouse and laboratory microcosms in the United States. In the first experiment, we used shading to reduce algal biomass, and because algal production and larval development might be a function of underlying soil nutrients, we crossed sun-shade treatments with soils of two distinct types collected near larval habitats. Shading reduced pupation rates and total adult biomass of An. gambiae by approximately 50%. Soil type had no significant effect on mosquito production, but it did significantly affect concentrations of phosphorus and chlorophyll a in the surface microlayer. In a subsequent experiment conducted in the greenhouse to reduce temperature differences found between the shaded and sunlit treatments, <1% of larvae in the shaded treatments reached the pupal stage. There was a marked reduction of chlorophyll a levels as a function of shading and larval density. In a third experiment, larvae receiving material harvested from sunlit surface microlayers performed as well as those receiving liver powder, whereas those receiving surface microlayer from shaded habitats suffered >90% mortality and failed to pupate. In a fourth experiment, glucose was added to shaded microcosms to stimulate bacterial activity in the absence of algae. Bacterial growth rates were 2 to 3 times higher, and larval development was enhanced in glucose-amended treatments. However, pupation rates and adult weights in glucose-amended shaded microcosms were still poor compared with those in nonamended sunlit microcosms. Overall, these results demonstrate the importance of algal biomass in the surface microlayers of larval habitats to development and adult production of An. gambiae.

  16. Larvicidal activity of medicinal plant extracts against Anopheles subpictus & Culex tritaeniorhynchus

    PubMed Central

    Kamaraj, C.; Bagavan, A.; Elango, G.; Zahir, A. Abduz; Rajakumar, G.; Marimuthu, S.; Santhoshkumar, T.; Rahuman, A. Abdul

    2011-01-01

    Background & objectives: Mosquitoes transmit serious human diseases, causing millions of deaths every year and the development of resistance to chemical insecticides resulting in rebounding vectorial capacity. Plants may be alternative sources of mosquito control agents. The present study assessed the role of larvicidal activities of hexane, chloroform, ethyl acetate, acetone, and methanol dried leaf and bark extracts of Annona squamosa L., Chrysanthemum indicum L., and Tridax procumbens L. against the fourth instar larvae of malaria vector, Anopheles subpictus Grassi and Japanese encephalitis vector, Culex tritaeniorhynchus Giles (Diptera: Culicidae). Methods: Larvicidal activities of three medicinal plant extracts were studied in the range of 4.69 to 1000 mg/l in the laboratory bioassays against early 4th instar larvae of An. subpictus and Cx. tritaeniorhynchus. The mortality data were subjected to probit analysis to determine the lethal concentrations (LC50 and LC90) to kill 50 and 90 per cent of the treated larvae of the respective species. Results: All plant extracts showed moderate effects after 24 h of exposure; however, the highest toxic effect of bark methanol extract of A. squamosa, leaf ethyl acetate extract of C. indicum and leaf acetone extract of T. procumbens against the larvae of An. subpictus (LC50 = 93.80, 39.98 and 51.57 mg/l) and bark methanol extract of A. squamosa, leaf methanol extract of C. indicum and leaf ethyl acetate extract of T. procumbens against the larvae of Cx. tritaeniorhynchus (LC50 =104.94, 42.29 and 69.16 mg/l) respectively. Interpretation & Conclusions: Our data suggest that the bark ethyl acetate and methanol extract of A. squamosa, leaf ethyl acetate and methanol extract of C. indicum, acetone and ethyl acetate extract of T. procumbens have the potential to be used as an ecofriendly approach for the control of the An. subpictus, and Cx. tritaeniorhynchus. PMID:21808141

  17. Screening of Methanolic Plant Extracts against Larvae of Aedes aegypti and Anopheles stephensi in Mysore

    PubMed Central

    Mohankumar, Thirumalapura Krishnaiah; Shivanna, Kumuda Sathigal; Achuttan, Vijayan Valiakottukal

    2016-01-01

    Background: Mosquitoes transmit serious human diseases, causing millions of death every year. Vector control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. Nine different locally available medicinally important plants suspected to posse larvicidal property were screened against fourth instar larvae of Aedes aegypti and Anopheles stephensi to a series of concentrations of the methanolic extracts. Methods: Susceptibility tests on Ae. aegypti and An. stephensi were conducted using standard WHO methods. The larvae of two mosquito species were exposed to methanolic extracts and mortality counts were made after 24 hours of exposure as per WHO method. Larvae of Ae. aegypti were more susceptible than that of An. stephensi. Results: Among the nine plant species tested, Annona reticulata leaf extract was more effective against Ae. aegypti larvae with LC50 and LC90 values of 95.24 and 262.64 ppm respectively and against An. stephensi larvae 262.71 and 636.94 ppm respectively. The least efficacy was in Cosmos bipinnatus with LC50 and LC90 values of 442.6 and 1225.93 ppm against Ae. aegypti and LC50 and LC90 values of 840.69 and 1334.01 ppm of Thespesia populnea against An. stephensi. Conclusion: The crude methanolic extract of the An. reticulata with good larvicidal efficacy could be considered for further characterization to control mosquito vectors instead of chemical insecticides. High efficacy found in An. reticulata extract will be considered for further studies to isolate the bioactive compound. PMID:27308289

  18. Molecular Evolution of Immune Genes in the Malaria Mosquito Anopheles gambiae

    PubMed Central

    Lehmann, Tovi; Hume, Jen C. C.; Licht, Monica; Burns, Christopher S.; Wollenberg, Kurt; Simard, Fred; Ribeiro, Jose' M. C.

    2009-01-01

    Background As pathogens that circumvent the host immune response are favoured by selection, so are host alleles that reduce parasite load. Such evolutionary processes leave their signature on the genes involved. Deciphering modes of selection operating on immune genes might reveal the nature of host-pathogen interactions and factors that govern susceptibility in host populations. Such understanding would have important public health implications. Methodology/Findings We analyzed polymorphisms in four mosquito immune genes (SP14D1, GNBP, defensin, and gambicin) to decipher selection effects, presumably mediated by pathogens. Using samples of Anopheles arabiensis, An. quadriannulatus and four An. gambiae populations, as well as published sequences from other Culicidae, we contrasted patterns of polymorphisms between different functional units of the same gene within and between populations. Our results revealed selection signatures operating on different time scales. At the most recent time scale, within-population diversity revealed purifying selection. Between populations and between species variation revealed reduced differentiation (GNBP and gambicin) at coding vs. noncoding- regions, consistent with balancing selection. McDonald-Kreitman tests between An. quadriannulatus and both sibling species revealed higher fixation rate of synonymous than nonsynonymous substitutions (GNBP) in accordance with frequency dependent balancing selection. At the longest time scale (>100 my), PAML analysis using distant Culicid taxa revealed positive selection at one codon in gambicin. Patterns of genetic variation were independent of exposure to human pathogens. Significance and Conclusions Purifying selection is the most common form of selection operating on immune genes as it was detected on a contemporary time scale on all genes. Selection for “hypervariability” was not detected, but negative balancing selection, detected at a recent evolutionary time scale between sibling

  19. Transcription Regulation of Sex-Biased Genes during Ontogeny in the Malaria Vector Anopheles gambiae

    PubMed Central

    Windbichler, Nikolai; Papathanos, Philippos-Aris; Nolan, Tony; Dottorini, Tania; Rizzi, Ermanno; Christophides, George K.; Crisanti, Andrea

    2011-01-01

    In Anopheles gambiae, sex-regulated genes are responsible for controlling gender dimorphism and are therefore crucial in determining the ability of female mosquitoes to transmit human malaria. The identification and functional characterization of these genes will shed light on the sexual development and maturation of mosquitoes and provide useful targets for genetic control measures aimed at reducing mosquito fertility and/or distorting the sex ratio. We conducted a genome wide transcriptional analysis of sex-regulated genes from early developmental stages through adulthood combined with functional screening of novel gonadal genes. Our results demonstrate that the male-biased genes undergo a major transcription turnover starting from larval stages to adulthood. The male biased genes at the adult stage include a significant high number of unique sequences compared to the rest of the genome. This is in contrast to female-biased genes that are much more conserved and are mainly activated during late developmental stages. The high frequency of unique sequences would indicate that male-biased genes evolve more rapidly than the rest of the genome. This finding is particularly intriguing because A. gambiae is a strictly female monogamous species suggesting that driving forces in addition to sperm competition must account for the rapid evolution of male-biased genes. We have also identified and functionally characterized a number of previously unknown A. gambiae testis- and ovary-specific genes. Two of these genes, zero population growth and a suppressor of defective silencing 3 domain of the histone deacetylase co-repressor complex, were shown to play a key role in gonad development. PMID:21738713

  20. Fitness consequences of larval exposure to Beauveria bassiana on adults of the malaria vector Anopheles stephensi.

    PubMed

    Vogels, Chantal B F; Bukhari, Tullu; Koenraadt, Constantianus J M

    2014-06-01

    Entomopathogenic fungi have shown to be effective in biological control of both larval and adult stages of malaria mosquitoes. However, a small fraction of mosquitoes is still able to emerge after treatment with fungus during the larval stage. It remains unclear whether fitness of these adults is affected by the treatment during the larval stage and whether they are still susceptible for another treatment during the adult stage. Therefore, we tested the effects of larval exposure to the entomopathogenic fungus Beauveria bassiana on fitness of surviving Anopheles stephensi females. Furthermore, we tested whether larval exposed females were still susceptible to re-exposure to the fungus during the adult stage. Sex ratio, survival and reproductive success were compared between non-exposed and larval exposed A. stephensi. Comparisons were also made between survival of non-exposed and larval exposed females that were re-exposed to B. bassiana during the adult stage. Larval treatment did not affect sex ratio of emerging mosquitoes. Larval exposed females that were infected died significantly faster and laid equal numbers of eggs from which equal numbers of larvae hatched, compared to non-exposed females. Larval exposed females that were uninfected had equal survival, but laid a significantly larger number of eggs from which a significantly higher number of larvae hatched, compared to non-exposed females. Larval exposed females which were re-exposed to B. bassiana during the adult stage had equal survival as females exposed only during the adult stage. Our results suggest that individual consequences for fitness of larval exposed females depended on whether a fungal infection was acquired during the larval stage. Larval exposed females remained susceptible to re-exposure with B. bassiana during the adult stage, indicating that larval and adult control of malaria mosquitoes with EF are compatible.

  1. Bacteria- and IMD Pathway-Independent Immune Defenses against Plasmodium falciparum in Anopheles gambiae

    PubMed Central

    Blumberg, Benjamin J.; Trop, Stefanie; Das, Suchismita; Dimopoulos, George

    2013-01-01

    The mosquito Anopheles gambiae uses its innate immune system to control bacterial and Plasmodium infection of its midgut tissue. The activation of potent IMD pathway-mediated anti-Plasmodium falciparum defenses is dependent on the presence of the midgut microbiota, which activate this defense system upon parasite infection through a peptidoglycan recognition protein, PGRPLC. We employed transcriptomic and reverse genetic analyses to compare the P. falciparum infection-responsive transcriptomes of septic and aseptic mosquitoes and to determine whether bacteria-independent anti-Plasmodium defenses exist. Antibiotic treated aseptic mosquitoes mounted molecular immune responses representing a variety of immune functions upon P. falciparum infection. Among other immune factors, our analysis uncovered a serine protease inhibitor (SRPN7) and Clip-domain serine protease (CLIPC2) that were transcriptionally induced in the midgut upon P. falciparum infection, independent of bacteria. We also showed that SRPN7 negatively and CLIPC2 positively regulate the anti-Plasmodium defense, independently of the midgut-associated bacteria. Co-silencing assays suggested that these two genes may function together in a signaling cascade. Neither gene was regulated, nor modulated, by infection with the rodent malaria parasite Plasmodium berghei, suggesting that SRPN7 and CLIPC2 are components of a defense system with preferential activity towards P. falciparum. Further analysis using RNA interference determined that these genes do not regulate the anti-Plasmodium defense mediated by the IMD pathway, and both factors act as agonists of the endogenous midgut microbiota, further demonstrating the lack of functional relatedness between these genes and the bacteria-dependent activation of the IMD pathway. This is the first study confirming the existence of a bacteria-independent, anti-P. falciparum defense. Further exploration of this anti-Plasmodium defense will help clarify determinants of

  2. Annotated differentially expressed salivary proteins of susceptible and insecticide-resistant mosquitoes of Anopheles stephensi.

    PubMed

    Vijay, Sonam; Rawal, Ritu; Kadian, Kavita; Raghavendra, Kamaraju; Sharma, Arun

    2015-01-01

    Vector control is one of the major global strategies for control of malaria. However, the major obstacle for vector control is the development of multiple resistances to organochlorine, organophosphorus insecticides and pyrethroids that are currently being used in public health for spraying and in bednets. Salivary glands of vectors are the first target organ for human-vector contact during biting and parasite-vector contact prior to parasite development in the mosquito midguts. The salivary glands secrete anti-haemostatic, anti-inflammatory biologically active molecules to facilitate blood feeding from the host and also inadvertently inject malaria parasites into the vertebrate host. The Anopheles stephensi mosquito, an urban vector of malaria to both human and rodent species has been identified as a reference laboratory model to study mosquito-parasite interactions. In this study, we adopted a conventional proteomic approach of 2D-electrophoresis coupled with MALDI-TOF mass spectrometry and bioinformatics to identify putative differentially expressed annotated functional salivary proteins between An. stephensi susceptible and multiresistant strains with same genetic background. Our results show 2D gel profile and MALDI-TOF comparisons that identified 31 differentially expressed putative modulated proteins in deltamethrin/DDT resistant strains of An. stephensi. Among these 15 proteins were found to be upregulated and 16 proteins were downregulated. Our studies interpret that An. stephensi (multiresistant) caused an upregulated expression of proteins and enzymes like cytochrome 450, short chain dehyrdogenase reductase, phosphodiesterase etc that may have an impact in insecticide resistance and xenobiotic detoxification. Our study elucidates a proteomic response of salivary glands differentially regulated proteins in response to insecticide resistance development which include structural, redox and regulatory enzymes of several pathways. These identified proteins

  3. Kinetic properties of alternatively spliced isoforms of laccase-2 from Tribolium castaneum and Anopheles gambiae

    PubMed Central

    Gorman, Maureen J.; Sullivan, Lucinda I.; Nguyen, Thi D. T.; Dai, Huaien; Arakane, Yasuyuki; Dittmer, Neal T.; Syed, Lateef U.; Li, Jun; Hua, Duy H.; Kanost, Michael R.

    2011-01-01

    Laccase-2 is a highly conserved multicopper oxidase that functions in insect cuticle pigmentation and tanning. In many species, alternative splicing gives rise to two laccase-2 isoforms. A comparison of laccase-2 sequences from three orders of insects revealed eleven positions at which there are conserved differences between the A and B isoforms. Homology modeling suggested that these eleven residues are not part of the substrate binding pocket. To determine whether the isoforms have different kinetic properties, we compared the activity of laccase-2 isoforms from Tribolium castaneum and Anopheles gambiae. We partially purified the four laccases as recombinant enzymes and analyzed their ability to oxidize a range of laccase substrates. The predicted endogenous substrates tested were dopamine, N-acetyldopamine (NADA), N-β-alanyldopamine (NBAD) and dopa, which were detected in T. castaneum previously and in A. gambiae as part of this study. Two additional diphenols (catechol and hydroquinone) and one non-phenolic substrate (2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)) were also tested. We observed no major differences in substrate specificity between the A and B isoforms. Dopamine, NADA and NBAD were oxidized with catalytic efficiencies ranging from 51 – 550 min−1 mM−1. These results support the hypothesis that dopamine, NADA and NBAD are endogenous substrates for both isoforms of laccase-2. Catalytic efficiencies associated with dopa oxidation were low, ranging from 8 – 30 min−1 mM−1; in comparison, insect tyrosinase oxidized dopa with a catalytic efficiency of 201 min−1 mM−1. We found that dopa had the highest redox potential of the four endogenous substrates, and this property of dopa may explain its poor oxidation by laccase-2. We conclude that laccase-2 splice isoforms are likely to oxidize the same substrates in vivo, and additional experiments will be required to discover any isoform-specific functions. PMID:22198355

  4. Evidence for X-linked introgression between molecular forms of Anopheles gambiae from Angola.

    PubMed

    Choi, K S; Townson, H

    2012-06-01

    The M and S molecular forms of the African malaria vector Anopheles gambiae (Diptera: Culicidae) are morphologically identical incipient species in which reproductive isolation is incomplete, enabling low-level gene flow between forms. In an attempt to find differences between the M and S forms, sequence variation was studied at loci along the X chromosome in adult female An. gambiae from Angola. A high proportion of M form specimens from Angola (79% of the 456 X chromosomes sampled) were found to contain a 16-bp insertion in intron 4 of the X-linked GPRCCK1 locus, relative to the AgamP3 release of the An. gambiae PEST genome sequence. The insertion was in Hardy-Weinberg equilibrium in Angolan M form populations. The same insertion was found in all S form specimens examined, regardless of where in Africa they were sampled, but was absent from a sample of M form specimens collected in Ghana, Bioko and Mali. In M form specimens from Angola, there was an association between alleles at the GPRCCK1 locus and those at a microsatellite locus, AGXH678, close to the centromere of the X chromosome, with significant linkage disequilibrium between loci separated by 0.472 Mbp (P < 0.033). We show that the insertion results from introgression from the S form into the M form, rather than from the retention of an ancestral character. Gene flow from the S to M form could allow genes of adaptive value to be transferred, including those conferring insecticide resistance and others influencing ecology and behaviour, and thus malaria transmission and control. We discuss factors that may have led to this introgression event.

  5. [Effectiveness of Bacillus sphaericus strain 2362 on larvae of Anopheles nuñeztovari].

    PubMed

    Rojas, J E; Mazzarri, M; Sojo, M; García-A, G Y

    2001-06-01

    A study, under laboratory and field conditions, was conducted to evaluate the effectiveness, persistence in the time and some factors that can affect the larvicidal action of the Griselef formulation of the sporogenous bacteria Bacillus sphaericus strain 2362, on the larvae population of the Anopheles nuñeztovari Gabaldón, the main malaria vector in western Venezuela. The degree of susceptibility of this species to the Bacillus sphaericus was determined to be at a LD50 in 0.07 ppm a LD95 in 0.69 ppm. The pH ranges of the water, as tested in the laboratory, showed that values between 7.0 and 9.0 did not affect the action of the larvicide, producing more than 95% of mortality after 72 hours of observation. Under controlled field conditions, the high susceptibility of the An. nuñeztovari larvae to the larvicidal action of the product was demonstrated. With a dose of 5 ml/m2, a 100% mortality was obtained after 72 hours of exposure. In the field, it was determined that after 12 hours, solar radiation decreased the effectiveness of the B. sphaericus in 30% and that the presence of vegetation reduced the biolarvicidal effect between 5 and 12%. Under natural field conditions, it was shown that the larvicide was effective, since a 100% larval mortality was obtained in the two treated breeding places. This effect persisted up to 4 months of observation, with more than 85% of larvae reduction, showing that it is capable or remaining in the natural environment.

  6. Chromosome Inversions, Genomic Differentiation and Speciation in the African Malaria Mosquito Anopheles gambiae

    PubMed Central

    Lee, Yoosook; Collier, Travis C.; Sanford, Michelle R.; Marsden, Clare D.; Fofana, Abdrahamane; Cornel, Anthony J.; Lanzaro, Gregory C.

    2013-01-01

    The African malaria vector, Anopheles gambiae, is characterized by multiple polymorphic chromosomal inversions and has become widely studied as a system for exploring models of speciation. Near complete reproductive isolation between different inversion types, known as chromosomal forms, has led to the suggestion that A. gambiae is in early stages of speciation, with divergence evolving in the face of considerable gene flow. We compared the standard chromosomal arrangement (Savanna form) with genomes homozygous for j, b, c, and u inversions (Bamako form) in order to identify regions of genomic divergence with respect to inversion polymorphism. We found levels of divergence between the two sub-taxa within some of these inversions (2Rj and 2Rb), but at a level lower than expected and confined near the inversion breakpoints, consistent with a gene flux model. Unexpectedly, we found that the majority of diverged regions were located on the X chromosome, which contained half of all significantly diverged regions, with much of this divergence located within exons. This is surprising given that the Bamako and Savanna chromosomal forms are both within the S molecular form that is defined by a locus near centromere of X chromosome. Two X-linked genes (a heat shock protein and P450 encoding genes) involved in reproductive isolation between the M and S molecular forms of A. gambiae were also significantly diverged between the two chromosomal forms. These results suggest that genes mediating reproductive isolation are likely located on the X chromosome, as is thought to be the case for the M and S molecular forms. We conclude that genes located on the sex chromosome may be the major force driving speciation between these chromosomal forms of A. gambiae. PMID:23526957

  7. The effect of dams and seasons on malaria incidence and anopheles abundance in Ethiopia

    PubMed Central

    2013-01-01

    Background Reservoirs created by damming rivers are often believed to increase malaria incidence risk and/or stretch the period of malaria transmission. In this paper, we report the effects of a mega hydropower dam on P. falciparum malaria incidence in Ethiopia. Methods A longitudinal cohort study was conducted over a period of 2 years to determine Plasmodium falciparum malaria incidence among children less than 10 years of age living near a mega hydropower dam in Ethiopia. A total of 2080 children from 16 villages located at different distances from a hydropower dam were followed up from 2008 to 2010 using active detection of cases based on weekly house to house visits. Of this cohort of children, 951 (48.09%) were females and 1059 (51.91%) were males, with a median age of 5 years. Malaria vectors were simultaneously surveyed in all the 16 study villages. Frailty models were used to explore associations between time-to-malaria and potential risk factors, whereas, mixed-effects Poisson regression models were used to assess the effect of different covariates on anopheline abundance. Results Overall, 548 (26.86%) children experienced at least one clinical malaria episode during the follow up period with mean incidence rate of 14.26 cases/1000 child-months at risk (95% CI: 12.16 - 16.36). P. falciparum malaria incidence showed no statistically significant association with distance from the dam reservoir (p = 0.32). However, P. falciparum incidence varied significantly between seasons (p < 0.01). The malaria vector, Anopheles arabiensis, was however more abundant in villages nearer to the dam reservoir. Conclusions P. falciparum malaria incidence dynamics were more influenced by seasonal drivers than by the dam reservoir itself. The findings could have implications in timing optimal malaria control interventions and in developing an early warning system in Ethiopia. PMID:23566411

  8. Multicopper oxidase-3 is a laccase associated with the peritrophic matrix of Anopheles gambiae.

    PubMed

    Lang, Minglin; Kanost, Michael R; Gorman, Maureen J

    2012-01-01

    The multicopper oxidase (MCO) family of enzymes includes laccases, which oxidize a broad range of substrates including polyphenols and phenylendiamines; ferroxidases, which oxidize ferrous iron; and several other oxidases with specific substrates such as ascorbate, bilirubin or copper. The genome of Anopheles gambiae, a species of mosquito, encodes five putative multicopper oxidases. Of these five, only AgMCO2 has known enzymatic and physiological functions: it is a highly conserved laccase that functions in cuticle pigmentation and tanning by oxidizing dopamine and dopamine derivatives. AgMCO3 is a mosquito-specific gene that is expressed predominantly in adult midguts and Malpighian tubules. To determine its enzymatic function, we purified recombinant AgMCO3 and analyzed its activity. AgMCO3 oxidized hydroquinone (a p-diphenol), the five o-diphenols tested, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), and p-phenylenediamine, but not ferrous iron. The catalytic efficiencies of AgMCO3 were similar to those of cuticular laccases (MCO2 orthologs), except that AgMCO3 oxidized all of the phenolic substrates with similar efficiencies whereas the MCO2 isoforms were less efficient at oxidizing catechol or dopa. These results demonstrate that AgMCO3 can be classified as a laccase and suggest that AgMCO3 has a somewhat broader substrate specificity than MCO2 orthologs. In addition, we observed AgMCO3 immunoreactivity in the peritrophic matrix, which functions as a selective barrier between the blood meal and midgut epithelial cells, protecting the midgut from mechanical damage, pathogens, and toxic molecules. We propose that AgMCO3 may oxidize toxic molecules in the blood meal leading to detoxification or to cross-linking of the molecules to the peritrophic matrix, thus targeting them for excretion.

  9. Studies on Anopheles sinensis, the vector species of vivax malaria in Korea

    PubMed Central

    2005-01-01

    Extensive previous studies on taxonomy, behavior/bionomics and control of Anopheles sinensis are reviewed and summarized. Recent molecular identification revealed that the population of An. sinensis complex includes An. sinensis, An. pullus, An. lesteri and at least two new species, and An. yatsushiroensis is synonmy of An. pullus. An. sinensis is the main vector specie of vivax malaria in Korea. Larvae of An. sinensis breed in wide range of habitats which are naturally-made clean water, stagnant or flowing; main habitats include rice fields, ditches, streams, irrigation cannals, marshes, ponds, ground pools, etc. Their host preferences are highly zoophilic. Human blood rate is very low (0.7-1.7%); nevertheless An. sinensis readily feeds on man when domestic animals are not found near by. They feed on hosts throughout the night from dusk to dawn with a peak period of 02:00-04:00 hours; they are slightly more exophagic (biting outdoors); much larger numbers come into the room when light is on. Main resting places are outdoors such as grasses, vegetable fields and rice fields. A mark-release-recapture study resulted that 37.1% was recaptured within 1 km, 29.4% at 1-3 km, 21.1% at 3-6 km, 10.3% at 6-9 km and 2.1% at 9-12 km distance. An. sinensis hibernate outdoors (mostly under part of dense grasses) during October-March. At the end of the hibernation period (March-April) they feed on cows at daytime. Until today any single measure to effectively control An. sinensis population has not been found. Indoor residual spray with a long-lasting insecticide can not reduce vector population densities, but shorten their life spans in some degree, so contributes to malaria control. PMID:16192749

  10. Anopheles atroparvus density modeling using MODIS NDVI in a former malarious area in Portugal.

    PubMed

    Lourenço, Pedro M; Sousa, Carla A; Seixas, Júlia; Lopes, Pedro; Novo, Maria T; Almeida, A Paulo G

    2011-12-01

    Malaria is dependent on environmental factors and considered as potentially re-emerging in temperate regions. Remote sensing data have been used successfully for monitoring environmental conditions that influence the patterns of such arthropod vector-borne diseases. Anopheles atroparvus density data were collected from 2002 to 2005, on a bimonthly basis, at three sites in a former malarial area in Southern Portugal. The development of the Remote Vector Model (RVM) was based upon two main variables: temperature and the Normalized Differential Vegetation Index (NDVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra satellite. Temperature influences the mosquito life cycle and affects its intra-annual prevalence, and MODIS NDVI was used as a proxy for suitable habitat conditions. Mosquito data were used for calibration and validation of the model. For areas with high mosquito density, the model validation demonstrated a Pearson correlation of 0.68 (p<0.05) and a modelling efficiency/Nash-Sutcliffe of 0.44 representing the model's ability to predict intra- and inter-annual vector density trends. RVM estimates the density of the former malarial vector An. atroparvus as a function of temperature and of MODIS NDVI. RVM is a satellite data-based assimilation algorithm that uses temperature fields to predict the intra- and inter-annual densities of this mosquito species using MODIS NDVI. RVM is a relevant tool for vector density estimation, contributing to the risk assessment of transmission of mosquito-borne diseases and can be part of the early warning system and contingency plans providing support to the decision making process of relevant authorities.

  11. Unbiased Characterization of Anopheles Mosquito Blood Meals by Targeted High-Throughput Sequencing.

    PubMed

    Logue, Kyle; Keven, John Bosco; Cannon, Matthew V; Reimer, Lisa; Siba, Peter; Walker, Edward D; Zimmerman, Peter A; Serre, David

    2016-03-01

    Understanding mosquito host choice is important for assessing vector competence or identifying disease reservoirs. Unfortunately, the availability of an unbiased method for comprehensively evaluating the composition of insect blood meals is very limited, as most current molecular assays only test for the presence of a few pre-selected species. These approaches also have limited ability to identify the presence of multiple mammalian hosts in a single blood meal. Here, we describe a novel high-throughput sequencing method that enables analysis of 96 mosquitoes simultaneously and provides a comprehensive and quantitative perspective on the composition of each blood meal. We validated in silico that universal primers targeting the mammalian mitochondrial 16S ribosomal RNA genes (16S rRNA) should amplify more than 95% of the mammalian 16S rRNA sequences present in the NCBI nucleotide database. We applied this method to 442 female Anopheles punctulatus s. l. mosquitoes collected in Papua New Guinea (PNG). While human (52.9%), dog (15.8%) and pig (29.2%) were the most common hosts identified in our study, we also detected DNA from mice, one marsupial species and two bat species. Our analyses also revealed that 16.3% of the mosquitoes fed on more than one host. Analysis of the human mitochondrial hypervariable region I in 102 human blood meals showed that 5 (4.9%) of the mosquitoes unambiguously fed on more than one person. Overall, analysis of PNG mosquitoes illustrates the potential of this approach to identify unsuspected hosts and characterize mixed blood meals, and shows how this approach can be adapted to evaluate inter-individual variations among human blood meals. Furthermore, this approach can be applied to any disease-transmitting arthropod and can be easily customized to investigate non-mammalian host sources.

  12. Egg hatching, larval movement and larval survival of the malaria vector Anopheles gambiae in desiccating habitats

    PubMed Central

    Koenraadt, Constantianus JM; Paaijmans, Krijn P; Githeko, Andrew K; Knols, Bart GJ; Takken, Willem

    2003-01-01

    Background Although the effects of rainfall on the population dynamics of the malaria vector Anopheles gambiae have been studied in great detail, the effects of dry periods on its survival remain less clear. Methods The effects of drying conditions were simulated by creating desiccated habitats, which consisted of trays filled with damp soil. Experiments were performed in these trays to (i) test the ability of An. gambiae sensu stricto eggs to hatch on damp soil and for larvae to reach an artificial breeding site at different distances of the site of hatching and (ii) to record survival of the four larval stages of An. gambiae s.s. when placed on damp soil. Results Eggs of An. gambiae s.s. hatched on damp soil and emerging larvae were capable of covering a distance of up to 10 cm to reach surface water enabling further development. However, proportions of larvae reaching the site decreased rapidly with increasing distance. First, second and third-instar larvae survived on damp soil for an estimated period of 64, 65 and 69 hrs, respectively. Fourth-instar larvae survived significantly longer and we estimated that the maximum survival time was 113 hrs. Conclusion Short-term survival of aquatic stages of An. gambiae on wet soil may be important and adaptive when considering the transient nature of breeding sites of this species in sub-Saharan Africa. In addition, the results suggest that, for larval vector control methods to be effective, habitats should remain drained for at least 5 days to kill all larvae (e.g. in rice fields) and habitats that recently dried up should be treated as well, if larvicidal agents are applied. PMID:12919636

  13. Biochemical characterization of chitin synthase activity and inhibition in the African malaria mosquito, Anopheles gambiae.

    PubMed

    Zhang, Xin; Yan Zhu, Kun

    2013-04-01

    Chitin synthase (CHS) is an important enzyme catalyzing the formation of chitin polymers in all chitin containing organisms and a potential target site for insect pest control. However, our understanding of biochemical properties of insect CHSs has been very limited. We here report enzymatic and inhibitory properties of CHS prepared from the African malaria mosquito, Anopheles gambiae. Our study, which represents the first time to use a nonradioactive method to assay CHS activity in an insect species, determined the optimal conditions for measuring the enzyme activity, including pH, temperature, and concentrations of the substrate uridine diphosphate N-acetyl-d-glucosamine (UDP-GlcNAc) and Mg(++) . The optimal pH was about 6.5-7.0, and the highest activity was detected at temperatures between 37°C and 44°C. Dithithreitol is required to prevent melanization of the enzyme extract. CHS activity was enhanced at low concentration of GlcNAc, but inhibited at high concentrations. Proteolytic activation of the activity is significant both in the 500 ×g supernatant and the 40 000 ×g pellet. Our study revealed only slight in vitro inhibition of A. gambiae CHS activity by diflubenzuron and nikkomycin Z at the highest concentration (2.5 μmol/L) examined. There was no in vitro inhibition by polyoxin D at any concentration examined. Furthermore, we did not observe any in vivo inhibition of CHS activity by any of these chemicals at any concentration examined. Our results suggest that the inhibition of chitin synthesis by these chemicals is not due to direct inhibition of CHS in A. gambiae.

  14. Chromosome inversions, genomic differentiation and speciation in the African malaria mosquito Anopheles gambiae.

    PubMed

    Lee, Yoosook; Collier, Travis C; Sanford, Michelle R; Marsden, Clare D; Fofana, Abdrahamane; Cornel, Anthony J; Lanzaro, Gregory C

    2013-01-01

    The African malaria vector, Anopheles gambiae, is characterized by multiple polymorphic chromosomal inversions and has become widely studied as a system for exploring models of speciation. Near complete reproductive isolation between different inversion types, known as chromosomal forms, has led to the suggestion that A. gambiae is in early stages of speciation, with divergence evolving in the face of considerable gene flow. We compared the standard chromosomal arrangement (Savanna form) with genomes homozygous for j, b, c, and u inversions (Bamako form) in order to identify regions of genomic divergence with respect to inversion polymorphism. We found levels of divergence between the two sub-taxa within some of these inversions (2Rj and 2Rb), but at a level lower than expected and confined near the inversion breakpoints, consistent with a gene flux model. Unexpectedly, we found that the majority of diverged regions were located on the X chromosome, which contained half of all significantly diverged regions, with much of this divergence located within exons. This is surprising given that the Bamako and Savanna chromosomal forms are both within the S molecular form that is defined by a locus near centromere of X chromosome. Two X-linked genes (a heat shock protein and P450 encoding genes) involved in reproductive isolation between the M and S molecular forms of A. gambiae were also significantly diverged between the two chromosomal forms. These results suggest that genes mediating reproductive isolation are likely located on the X chromosome, as is thought to be the case for the M and S molecular forms. We conclude that genes located on the sex chromosome may be the major force driving speciation between these chromosomal forms of A. gambiae.

  15. Adaptive divergence between incipient species of Anopheles gambiae increases resistance to Plasmodium

    PubMed Central

    White, Bradley J.; Lawniczak, Mara K. N.; Cheng, Changde; Coulibaly, Mamadou B.; Wilson, Michael D.; Sagnon, N'Fale; Costantini, Carlo; Simard, Frederic; Christophides, George K.; Besansky, Nora J.

    2011-01-01

    The African malaria mosquito Anopheles gambiae is diversifying into ecotypes known as M and S forms. This process is thought to be promoted by adaptation to different larval habitats, but its genetic underpinnings remain elusive. To identify candidate targets of divergent natural selection in M and S, we performed genomewide scanning in paired population samples from Mali, followed by resequencing and genotyping from five locations in West, Central, and East Africa. Genome scans revealed a significant peak of M-S divergence on chromosome 3L, overlapping five known or suspected immune response genes. Resequencing implicated a selective target at or near the TEP1 gene, whose complement C3-like product has antiparasitic and antibacterial activity. Sequencing and allele-specific genotyping showed that an allelic variant of TEP1 has been swept to fixation in M samples from Mali and Burkina Faso and is spreading into neighboring Ghana, but is absent from M sampled in Cameroon, and from all sampled S populations. Sequence comparison demonstrates that this allele is related to, but distinct from, TEP1 alleles of known resistance phenotype. Experimental parasite infections of advanced mosquito intercrosses demonstrated a strong association between this TEP1 variant and resistance to both rodent malaria and the native human malaria parasite Plasmodium falciparum. Although malaria parasites may not be direct agents of pathogen-mediated selection at TEP1 in nature—where larvae may be the more vulnerable life stage—the process of adaptive divergence between M and S has potential consequences for malaria transmission. PMID:21173248

  16. Inversion 2La is associated with enhanced desiccation resistance in Anopheles gambiae

    PubMed Central

    Gray, Emilie M; Rocca, Kyle AC; Costantini, Carlo; Besansky, Nora J

    2009-01-01

    Background Anopheles gambiae, the principal vector of malignant malaria in Africa, occupies a wide range of habitats. Environmental flexibility may be conferred by a number of chromosomal inversions non-randomly associated with aridity, including 2La. The purpose of this study was to determine the physiological mechanisms associated with the 2La inversion that may result in the preferential survival of its carriers in hygrically-stressful environments. Methods Two homokaryotypic populations of A. gambiae (inverted 2La and standard 2L+a) were created from a parental laboratory colony polymorphic for 2La and standard for all other known inversions. Desiccation resistance, water, energy and dry mass of adult females of both populations were compared at several ages and following acclimation to a more arid environment. Results Females carrying 2La were significantly more resistant to desiccation than 2L+a females at emergence and four days post-emergence, for different reasons. Teneral 2La females had lower rates of water loss than their 2L+a counterparts, while at four days, 2La females had higher initial water content. No differences in desiccation resistance were found at eight days, with or without acclimation. However, acclimation resulted in both populations significantly reducing their rates of water loss and increasing their desiccation resistance. Acclimation had contrasting effects on the body characteristics of the two populations: 2La females boosted their glycogen stores and decreased lipids, whereas 2La females did the contrary. Conclusion Variation in rates of water loss and response to acclimation are associated with alternative arrangements of the 2La inversion. Understanding the mechanisms underlying these traits will help explain how inversion polymorphisms permit exploitation of a heterogeneous environment by this disease vector. PMID:19772577

  17. Odorant-Binding Proteins of the Malaria Mosquito Anopheles funestus sensu stricto

    PubMed Central

    Xu, Wei; Cornel, Anthony J.; Leal, Walter S.

    2010-01-01

    Background The mosquito Anopheles funestus is one of the major malaria vector species in sub-Saharan Africa. Olfaction is essential in guiding mosquito behaviors. Odorant-binding proteins (OBPs) are highly expressed in insect olfactory tissues and involved in the first step of odorant reception. An improved understanding of the function of malaria mosquito OBPs may contribute to identifying new attractants/repellents and assist in the development of more efficient and environmentally friendly mosquito controlling strategies. Methodology In this study, a large screening of over 50 ecologically significant odorant compounds led to the identification of 12 ligands that elicit significant electroantennographic (EAG) responses from An. funestus female antennae. To compare the absolute efficiency/potency of these chemicals, corrections were made for differences in volatility by determining the exact amount in a stimulus puff. Fourteen AfunOBP genes were cloned and their expression patterns were analyzed. AfunOBP1, 3, 7, 20 and 66 showed olfactory tissue specificity by reverse transcriptase PCR (RT-PCR). Quantitative real-time PCR (qRT-PCR) analysis showed that among olfactory-specific OBPs, AfunOBP1 and 3 are the most enriched OBPs in female antennae. Binding assay experiments showed that at pH 7, AfunOBP1 significantly binds to 2-undecanone, nonyl acetate, octyl acetate and 1-octen-3-ol but AfunOBP3, which shares 68% identify with AfunOBP1 at amino acid level, showed nearly no binding activity to the selected 12 EAG-active odorant compounds. Conclusion This work presents for the first time a study on the odorants and OBPs of the malaria vector mosquito An. funestus, which may provide insight into the An. funestus olfactory research, assist in a comparative study between major malaria mosquitoes An. gambiae and An. funestus olfactory system, and help developing new mosquito control strategies to reduce malaria transmission. PMID:21042539

  18. Predictions of adult Anopheles albimanus densities in villages based on distances to remotely sensed larval habitats

    NASA Technical Reports Server (NTRS)

    Rejmankova, E.; Roberts, D. R.; Pawley, A.; Manguin, S.; Polanco, J.

    1995-01-01

    Remote sensing is particularly helpful for assessing the location and extent of vegetation formations, such as herbaceous wetlands, that are difficult to examine on the ground. Marshes that are sparsely populated with emergent macrophytes and dense cyanobacterial mats have previously been identified as very productive Anopheles albimanus larval habitats. This type of habitat was detectable on a classified multispectral System Probatoire d'Observation de la Terre image of northern Belize as a mixture of two isoclasses. A similar spectral signature is characteristic for vegetation of river margins consisting of aquatic grasses and water hyacinth, which constitutes another productive larval habitat. Based on the distance between human settlements (sites) of various sizes and the nearest marsh/river exhibiting this particular class combination, we selected two groups of sites: those located closer than 500 m and those located more than 1,500 m from such habitats. Based on previous adult collections near larval habitats, we defined a landing rate of 0.5 mosquitoes/human/min from 6:30 PM to 8:00 PM as the threshold for high (> or = 0.5 mosquitoes/human/min) versus low (< 0.5 mosquitoes/human/min) densities of An. albimanus. Sites located less than 500 m from the habitat were predicted as having values higher than this threshold, while lower values were predicted for sites located greater than 1,500 m from the habitat. Predictions were verified by collections of mosquitoes landing on humans. The predictions were 100% accurate for sites in the > 1,500-m category and 89% accurate for sites in the < 500-m category.

  19. Transcriptome Sequencing and Developmental Regulation of Gene Expression in Anopheles aquasalis

    PubMed Central

    Silva, Maria C. P.; Lopes, Adriana R.; Barros, Michele S.; Sá-Nunes, Anderson; Kojin, Bianca B.; Carvalho, Eneas; Suesdek, Lincoln; Silva-Neto, Mário Alberto C.; James, Anthony A.; Capurro, Margareth L.

    2014-01-01

    Background Anopheles aquasalis is a major malaria vector in coastal areas of South and Central America where it breeds preferentially in brackish water. This species is very susceptible to Plasmodium vivax and it has been already incriminated as responsible vector in malaria outbreaks. There has been no high-throughput investigation into the sequencing of An. aquasalis genes, transcripts and proteins despite its epidemiological relevance. Here we describe the sequencing, assembly and annotation of the An. aquasalis transcriptome. Methodology/Principal Findings A total of 419 thousand cDNA sequence reads, encompassing 164 million nucleotides, were assembled in 7544 contigs of ≥2 sequences, and 1999 singletons. The majority of the An. aquasalis transcripts encode proteins with their closest counterparts in another neotropical malaria vector, An. darlingi. Several analyses in different protein databases were used to annotate and predict the putative functions of the deduced An. aquasalis proteins. Larval and adult-specific transcripts were represented by 121 and 424 contig sequences, respectively. Fifty-one transcripts were only detected in blood-fed females. The data also reveal a list of transcripts up- or down-regulated in adult females after a blood meal. Transcripts associated with immunity, signaling networks and blood feeding and digestion are discussed. Conclusions/Significance This study represents the first large-scale effort to sequence the transcriptome of An. aquasalis. It provides valuable information that will facilitate studies on the biology of this species and may lead to novel strategies to reduce malaria transmission on the South American continent. The An. aquasalis transcriptome is accessible at http://exon.niaid.nih.gov/transcriptome/An_aquasalis/Anaquexcel.xlsx. PMID:25033462

  20. The Maternally Inheritable Wolbachia wAlbB Induces Refractoriness to Plasmodium berghei in Anopheles stephensi

    PubMed Central

    Joshi, Deepak; Pan, Xiaoling; McFadden, Michael J.; Bevins, David; Liang, Xiao; Lu, Peng; Thiem, Suzanne; Xi, Zhiyong

    2017-01-01

    The endosymbiont Wolbachia wAlbB induces refractoriness to Plasmodium falciparum in Anopheles stephensi, the primary mosquito vector of human malaria in the Middle East and South Asia. However, it remains unknown whether such refractoriness can be extended to other malaria species. In particular, it was reported that under very specific conditions, wAlbB can enhance Plasmodium infection in some hosts. Here, we measured the impact of wAlbB on the rodent malaria parasite Plasmodium berghei in A. stephensi by comparing the load of oocysts and sporozoites in midguts and salivary glands, respectively, between wAlbB-infected and -uninfected mosquitoes. To investigate whether wAlbB modulated mosquito immune defense against parasites, we compared the expression of the immune genes, which were previously reported to involve in antimalarial response, in both midguts and the remaining carcass tissues of mosquitoes. The stable association of wAlbB with A. stephensi resulted in reduction of parasites by more than half at the oocyst stage, and up to 91.8% at the sporzoite stage. The anti-plasmodium immune genes, including TEP1, LRIM1, Toll pathway gene Rel1 and the effector Defensin 1, were induced by wAlbB in different mosquito body tissues. These findings suggest that immune priming is a potential cause of wAlbB-mediated antimalarial response in A. stephensi. More importantly, no evidence was found for any enhancement of Plasmodium infection in A. stephensi stably infected with wAlbB. We discuss these findings with possible implementations of Wolbachia for malaria control in disease endemic areas. PMID:28337184

  1. Delayed egg hatching of Anopheles gambiae (Diptera: Culicidae) pending water agitation.

    PubMed

    Ebrahimi, Babak; Shakibi, Sanam; Foster, Woodbridge A

    2014-05-01

    Mosquito eggs laid on water surfaces typically hatch spontaneously soon after the embryos within them become fully formed first-instar larvae. However, we have found that Anopheles gambiae Giles, an important vector of malaria in Africa, exhibits delayed hatching until the water surface is agitated, a feature overlooked in most laboratory colonies. Agitation within 24 h postoviposition, before embryonation was complete, failed to stimulate delayed postembryonic hatching of isolated eggs on the following day (day 2), when < 1% had hatched spontaneously. However, 5 min of water agitation of these dormant pharate first-instar larvae on day 2 resulted in an almost immediate hatch of 63.3 versus 0% of nonagitated controls, plus another 3.9 versus 0.3%, respectively, during the following 24 h. With daily agitation, installment hatching occurred mainly during 2-6 d postoviposition. The mean cumulative hatch after 7 d of daily agitation was 83.1 versus 1.1% of nonagitated eggs. Experiments with eggs in groups demonstrated that egg density and activity of already-hatched larvae had no stimulatory effect. Eggs stored 1-4 wk at 25.5 or at 15.5 degrees C, and then agitated daily for 6 d at 25.5 degrees C, showed a gradual decline in viability. Viability was sustained longer at the lower temperature. Implications of agitation-induced egg hatching for rainy-season and dry-season ecology of An. gambiae are discussed. Suspended hatching and cool storage already are proving convenient for efficient mass rearing and accurate modeling of weather-based population dynamics.

  2. Stereoscopic Video Analysis of Anopheles gambiae Behavior in the Field: Challenges and Opportunities

    PubMed Central

    Manoukis, Nicholas C.; Butail, Sachit; Diallo, Moussa; Ribeiro, José MC; Paley, Derek A.

    2013-01-01

    Advances in our ability to localize and track individual swarming mosquitoes in the field via stereoscopic image analysis have enabled us to test long-standing ideas about individual male behavior and directly observe coupling. These studies further our fundamental understanding of the reproductive biology of mosquitoes. In addition, our analysis using stereoscopic video of swarms of the African malaria vector Anopheles gambiae have produced results that should be relevant to any “release-based” method of control including Sterile Insect Technique (SIT) and genetically modified male mosquitoes (GMM). The relevance of the results is primarily due to the fact that any mosquito vectors released for control are almost certainly going to be males; further, for SIT, GMM or similar approaches to be successful, the released males will have to successfully locate swarms and then mate with wild females. Thus, understanding and potentially manipulating the mating process could play a key role in future control programs. Our experience points to special challenges created by stereoscopic video of swarms. These include the expected technical difficulties of capturing usable images of mosquitoes in the field, and creating an automated tracking system to enable generation of large numbers of three dimensional tracks over many seconds of footage. Once the data are collected, visualization and application of appropriate statistical and analytic methods also are required. We discuss our recent progress on these problems, give an example of a statistical approach to quantify individual male movement in a swarm with some novel results, and suggest further studies incorporating experimental manipulation and three dimensional localization and tracking of individual mosquitoes in wild swarms. PMID:23850507

  3. Characterization of the target of ivermectin, the glutamate-gated chloride channel, from Anopheles gambiae

    PubMed Central

    Meyers, Jacob I.; Gray, Meg; Kuklinski, Wojtek; Johnson, Lucas B.; Snow, Christopher D.; Black, William C.; Partin, Kathryn M.; Foy, Brian D.

    2015-01-01

    ABSTRACT The use of insecticide-treated nets and indoor residual insecticides targeting adult mosquito vectors is a key element in malaria control programs. However, mosquito resistance to the insecticides used in these applications threatens malaria control efforts. Recently, the mass drug administration of ivermectin (IVM) has been shown to kill Anopheles gambiae mosquitoes and disrupt Plasmodium falciparum transmission in the field. We cloned the molecular target of IVM from A. gambiae, the glutamate-gated chloride channel (AgGluCl), and characterized its transcriptional patterns, protein expression and functional responses to glutamate and IVM. AgGluCl cloning revealed an unpredicted fourth splice isoform as well as a novel exon and splice site. The predicted gene products contained heterogeneity in the N-terminal extracellular domain and the intracellular loop region. Responses to glutamate and IVM were measured using two-electrode voltage clamp on Xenopus laevis oocytes expressing AgGluCl. IVM induced non-persistent currents in AgGluCl-a1 and did not potentiate glutamate responses. In contrast, AgGluCl-b was insensitive to IVM, suggesting that the AgGluCl gene could produce IVM-sensitive and -insensitive homomultimers from alternative splicing. AgGluCl isoform-specific transcripts were measured across tissues, ages, blood feeding status and sex, and were found to be differentially transcribed across these physiological variables. Lastly, we stained adult, female A. gambiae for GluCl expression. The channel was expressed in the antenna, Johnston's organ, supraesophageal ganglion and thoracic ganglia. In summary, we have characterized the first GluCl from a mosquito, A. gambiae, and described its unique activity and expression with respect to it as the target of the insecticide IVM. PMID:25994631

  4. Characterization of the target of ivermectin, the glutamate-gated chloride channel, from Anopheles gambiae.

    PubMed

    Meyers, Jacob I; Gray, Meg; Kuklinski, Wojtek; Johnson, Lucas B; Snow, Christopher D; Black, William C; Partin, Kathryn M; Foy, Brian D

    2015-05-15

    The use of insecticide-treated nets and indoor residual insecticides targeting adult mosquito vectors is a key element in malaria control programs. However, mosquito resistance to the insecticides used in these applications threatens malaria control efforts. Recently, the mass drug administration of ivermectin (IVM) has been shown to kill Anopheles gambiae mosquitoes and disrupt Plasmodium falciparum transmission in the field. We cloned the molecular target of IVM from A. gambiae, the glutamate-gated chloride channel (AgGluCl), and characterized its transcriptional patterns, protein expression and functional responses to glutamate and IVM. AgGluCl cloning revealed an unpredicted fourth splice isoform as well as a novel exon and splice site. The predicted gene products contained heterogeneity in the N-terminal extracellular domain and the intracellular loop region. Responses to glutamate and IVM were measured using two-electrode voltage clamp on Xenopus laevis oocytes expressing AgGluCl. IVM induced non-persistent currents in AgGluCl-a1 and did not potentiate glutamate responses. In contrast, AgGluCl-b was insensitive to IVM, suggesting that the AgGluCl gene could produce IVM-sensitive and -insensitive homomultimers from alternative splicing. AgGluCl isoform-specific transcripts were measured across tissues, ages, blood feeding status and sex, and were found to be differentially transcribed across these physiological variables. Lastly, we stained adult, female A. gambiae for GluCl expression. The channel was expressed in the antenna, Johnston's organ, supraesophageal ganglion and thoracic ganglia. In summary, we have characterized the first GluCl from a mosquito, A. gambiae, and described its unique activity and expression with respect to it as the target of the insecticide IVM.

  5. Identification of the Temperature Induced Larvicidal Efficacy of Agave angustifolia against Aedes, Culex, and Anopheles Larvae

    PubMed Central

    Kajla, Mithilesh; Bhattacharya, Kurchi; Gupta, Kuldeep; Banerjee, Ujjwal; Kakani, Parik; Gupta, Lalita; Kumar, Sanjeev

    2016-01-01

    Synthetic insecticides are generally employed to control the mosquito population. However, their injudicious over usage and non-biodegradability are associated with many adverse effects on the environment and mosquitoes. The application of environment-friendly mosquitocidals might be an alternate to overcome these issues. In this study, we found that organic or aqueous extracts of Agave angustifolia leaves exhibited a strong larvicidal activity (LD50 28.27 μg/ml) against Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi larvae within a short exposure of 12 h. The larvicidal activity of A. angustifolia is inherited and independent of the plants vegetative growth. Interestingly, the plant larvicidal activity was observed exclusively during the summer season (April–August, when outside temperature is between 30 and 50°C) and it was significantly reduced during winter season (December–February, when the outside temperature falls to ~4°C or lower). Thus, we hypothesized that the larvicidal components of A. angustifolia might be induced by the manipulation of environmental temperature and should be resistant to the hot conditions. We found that the larvicidal activity of A. angustifolia was induced when plants were maintained at 37°C in a semi-natural environment against the controls that were growing outside in cold weather. Pre-incubation of A. angustifolia extract at 100°C for 1 h killed 60% larvae in 12 h, which gradually increased to 100% mortality after 24 h. In addition, the dry powder formulation of A. angustifolia, also displayed a strong larvicidal activity after a long shelf life. Together, these findings revealed that A. angustifolia is an excellent source of temperature induced bioactive metabolites that may assist the preparedness for vector control programs competently. PMID:26793700

  6. Experimental evaluation of overhanging bamboo in Anopheles darlingi larval habitat selection in Belize, Central America.

    PubMed

    Achee, Nicole L; Grieco, John P; Andre, Richard G; Roberts, Donald R; Rejmankova, Eliska

    2006-06-01

    Previous studies in Belize have shown the preferred breeding habitats of the malaria vector Anopheles darlingi were floating detritus patches within riverine systems that were associated with overhanging bamboo. The present study focused on an experimental evaluation of overhanging bamboo in An. darlingi habitat selection using larval counts as an indicator of attractiveness. Four sets of 1-m2 floating screened enclosures were placed at a location with a documented presence of both larval and adult An. darlingi populations. Each enclosure set comprised a control (i.e., open water) and three other experimental treatments consisting of: 1) detritus, 2) detritus with overhanging bamboo, and 3) overhanging bamboo alone. Larvae were sampled from all treatments on Day 5, Day 11, and Day 17 post-setup. A total of 2,461 An. darlingi larvae were collected and identified from three trials conducted from March-May 2002. Of these, 1,997 larvae were sampled from detritus treatments, 256 from enclosures with bamboo and detritus, 139 from bamboo treatments, and 69 from control enclosures. The detritus treatment had a significantly higher average count of An. darlingi larvae than the other treatments (P<0.01), and no difference existed between the control treatment and the treatment containing overhanging bamboo alone (P=0.423). More importantly, enclosures containing the overhanging bamboo with detritus treatments did not have greater larval populations than the enclosures with only detritus. These data suggest that bamboo does not contribute to An. darlingi larval habitat attractiveness but may function as a barrier to surface water flow causing the lodging of debris, the preferred habitat, that will then attract gravid females for oviposition.

  7. The Anopheles superpictus complex: introduction of a new malaria vector complex in Iran.

    PubMed

    Oshaghi, M A; Yaghobi-Ershadi, M R; Shemshad, K; Pedram, M; Amani, H

    2008-12-01

    Anopheles superpictus Grassi is one of the most widespread malaria vectors in Iran. Two morphologically independent forms of this mosquito, both at larval and adult stage as well as a great diversity in its mtDNA loci have been previously described in Iran. Because of existence of mtDNA haplotypes, co-occurrence of two forms in diverse climates as well as different roles of populations played in malaria transmission, we hypothesized the possibility of emerging species (or sub-species) within the taxon. We surveyed the molecular variation in sympatric and allopatric populations of the two forms, using sequences from the ribosomal-DNA spacer region (ITS2). This analysis revealed a high degree of polymorphism (32.3%) as well as a length polymorphism (357 vs. 378 bp) in the ITS2 region among the populations but not so among morphological forms. Further examination identified three different ITS2 sequences, designated as genotypes X, Y and Z within species. Interestingly, while the sympatric Y and Z genotypes appear to be exclusive to the populations from the southeastern part of the country, genotype X is geographically separated and present in the North, the West, the South and the Central territories. The degree of divergence in ITS2 is much more than an intra-specific variation seen within the anopheline mosquitoes, and it points out the possibility of cryptic species within the taxon. Further studies are necessary to identify the species composition of the An. superpictus and their role played in the transmission of malaria in its geographical range.

  8. CLIPB8 is part of the prophenoloxidase activation system in Anopheles gambiae mosquitoes.

    PubMed

    Zhang, Xin; An, Chunju; Sprigg, KaraJo; Michel, Kristin

    2016-04-01

    In insects and other arthropods the formation of eumelanin (melanization) is a broad spectrum and potent immune response that is used to encapsulate and kill invading pathogens. This immune response is regulated by the activation of prophenoxidase (proPO), which is controlled by proteinase cascades and its serpin inhibitors, together forming the proPO activation system. While the molecular composition of these protease cascades are well understood in insect model systems, major knowledge gaps remain in mosquitoes. Recently, a regulatory unit of melanization in Anopheles gambiae was documented, comprised of the inhibitory serpin-clip-serine proteinase, CLIPB9 and its inhibitor serpin-2 (SRPN2). Partial reversion of SRPN2 phenotypes in melanotic tumor formation and adult survival by SRPN2/CLIPB9 double knockdown suggested other target proteinases of SRPN2 in regulating melanization. Here we report that CLIPB8 supplements the SRPN2/CLIPB9 regulatory unit in controlling melanization in An. gambiae. As with CLIPB9, knockdown of CLIPB8 partially reversed the pleiotropic phenotype induced by SRPN2 silencing with regards to adult survival and melanotic tumor formation. Recombinant SRPN2 protein formed an SDS-stable protein complex with activated recombinant CLIPB8, however did not efficiently inhibit CLIPB8 activity in vitro. CLIPB8 did not directly activate proPO in vitro nor was it able to cleave and activate proCLIPB9. Nevertheless, epistasis analysis using RNAi placed CLIPB8 and CLIPB9 in the same pathway leading to melanization, suggesting that CLIPB8 either acts further upstream of CLIPB9 or is required for activation of a yet to be identified serine proteinase homolog. Taken together, this study identifies CLIPB8 as an additional player in proPO activation cascade and highlights the complexity of the proteinase network that regulates melanization in An. gambiae.

  9. Wolbachia Stimulates Immune Gene Expression and Inhibits Plasmodium Development in Anopheles gambiae

    PubMed Central

    Kambris, Zakaria; Blagborough, Andrew M.; Pinto, Sofia B.; Blagrove, Marcus S. C.; Godfray, H. Charles J.; Sinden, Robert E.; Sinkins, Steven P.

    2010-01-01

    The over-replicating wMelPop strain of the endosymbiont Wolbachia pipientis has recently been shown to be capable of inducing immune upregulation and inhibition of pathogen transmission in Aedes aegypti mosquitoes. In order to examine whether comparable effects would be seen in the malaria vector Anopheles gambiae, transient somatic infections of wMelPop were created by intrathoracic inoculation. Upregulation of six selected immune genes was observed compared to controls, at least two of which (LRIM1 and TEP1) influence the development of malaria parasites. A stably infected An. gambiae cell line also showed increased expression of malaria-related immune genes. Highly significant reductions in Plasmodium infection intensity were observed in the wMelPop-infected cohort, and using gene knockdown, evidence for the role of TEP1 in this phenotype was obtained. Comparing the levels of upregulation in somatic and stably inherited wMelPop infections in Ae. aegypti revealed that levels of upregulation were lower in the somatic infections than in the stably transinfected line; inhibition of development of Brugia filarial nematodes was nevertheless observed in the somatic wMelPop infected females. Thus we consider that the effects observed in An. gambiae are also likely to be more pronounced if stably inherited wMelPop transinfections can be created, and that somatic infections of Wolbachia provide a useful model for examining effects on pathogen development or dissemination. The data are discussed with respect to the comparative effects on malaria vectorial capacity of life shortening and direct inhibition of Plasmodium development that can be produced by Wolbachia. PMID:20949079

  10. Ex vivo promoter analysis of antiviral heat shock cognate 70B gene in Anopheles gambiae

    PubMed Central

    Kang, Seokyoung; Sim, Cheolho; Byrd, Brian D; Collins, Frank H; Hong, Young S

    2008-01-01

    Background The Anopheles gambiae heat shock cognate gene (hsc70B) encodes a constitutively expressed protein in the hsp70 family and it functions as a molecular chaperone for prot