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Sample records for dengue em larvas

  1. Dengue virus detection in Aedes aegypti larvae from southeastern Brazil.

    PubMed

    Cecílio, Samyra Giarola; Júnior, Willer Ferreira Silva; Tótola, Antônio Helvécio; de Brito Magalhães, Cíntia Lopes; Ferreira, Jaqueline Maria Siqueira; de Magalhães, José Carlos

    2015-06-01

    The transmission of dengue, the most important arthropod-borne viral disease in Brazil, has been intensified over the past decades, along with the accompanying expansion and adaptation of its Aedes vectors. In the present study, we mapped dengue vectors in Ouro Preto and Ouro Branco, Minas Gerais, by installing ovitraps in 32 public schools. The traps were examined monthly between September, 2011 through July, 2012 and November, 2012 to April, 2013. The larvae were reared until the fourth stadium and identified according to species. The presence of dengue virus was detected by real time PCR and agarose gel electrophoresis. A total of 1,945 eggs was collected during the 17 months of the study. The Ovitrap Positivity Index (OPI) ranged from 0 to 28.13% and the Eggs Density Index (EDI) ranged from 0 to 59.9. The predominant species was Aedes aegypti, with 84.9% of the hatched larvae. Although the collection was low when compared to other ovitraps studies, vertical transmission could be detected. Of the 54 pools, dengue virus was detected in four Ae. aegypti pools.

  2. Dengue

    MedlinePlus

    ... Testing Epidemiologists Journalists Dengue Branch News Dengue and Climate Dengue Update About CDC's Dengue Branch Dengue in ... Mosquito Life-Cycle Mosquito Aquatic Habitats Dengue And Climate Clinical/Laboratory Guidance Clinical Guidance Laboratory Guidance Real- ...

  3. Distribution of container-inhabiting Aedes larvae (Diptera: Culicidae) at a dengue focus in Thailand.

    PubMed

    Kittayapong, P; Strickman, D

    1993-05-01

    A Thai village with dengue transmission was surveyed for Aedes aegypti (L.) and Ae. albopictus (Skuse) larvae at the end of the rainy season. All containers (1,819) in 186 households were surveyed, recording the presence of larvae, container type, level of water, kind of cover, and location. The number of positive containers was proportional to the total number of containers in a household. Standard water jars (approximately 200 liters) contributed 57% and small water jars (< 100 liters) contributed 16% of the total infested containers. Each of the other 10 container types contributed < or = 10% of the total infested containers and were not statistically different from each other. Containers inside houses were infested significantly more often than were those outdoors, those under elevated houses or roofs, or those in bathrooms. Unexpectedly, standard water jars located outdoors that were covered with commercial metal lids were infested significantly more often than were uncovered jars.

  4. Dengue

    MedlinePlus

    Dengue is an infection caused by a virus. You can get it if an infected mosquito bites you. Dengue does not spread from person to person. It ... the world. Outbreaks occur in the rainy season. Dengue is rare in the United States. Symptoms include ...

  5. Scanning electron microscopy of damage caused by Mesocyclops thermocyclopoides (Copepoda: Cyclopoidea) on larvae of the Dengue fever vector Aedes aegypti (Diptera: Culicidae).

    PubMed

    Schaper, Stefan; Hernández-Chavarría, Francisco

    2006-09-01

    Dengue fever is a mosquito-borne viral disease, whose main biological vector is Aedes aegypti. This mosquito colonizes tropical areas where the disease is endemic. The most obvious action against dengue is attacking its vector. Biological control appears to be an alternative approach, using natural enemies of the mosquitoes, such as predatory copepods. Thus, the morphological study of the damage caused by copepods is important to understand its predatory capacity. Twenty-five A. aegypti larvae were exposed to the copepod Mesocyclops thermocyclopoides and the damage caused by the copepods was evaluated using scanning electron microscopy. The larvae showed damage mainly at the anal segment, the siphon and the abdomen; only three attacks to the head were observed. The size of the siphon might be of importance in determining whether or not a copepod will attack a mosquito larva.

  6. Bioactivity of seagrass against the dengue fever mosquito Aedes aegypti larvae.

    PubMed

    Ali, M Syed; Ravikumar, S; Beula, J Margaret

    2012-07-01

    To identify the larvicidal activity of the seagrass extracts. Seagrass extracts, Syringodium isoetifolium (S. isoetifolium), Cymodocea serrulata and Halophila beccarii, were dissolved in DMSO to prepare a graded series of concentration. Batches of 25 early 4th instars larvae of Aedes aegypti (Ae. aegypti) were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (0.01 mg - 0.1 mg). After 24 h the mortality rate was identified with the formulae [(% of test mortality - % of control mortality)/(100 - % of control mortality)] × 100. Each experiment was conducted with three replicates and a concurrent control group. A control group consisted of 1 mL of DMSO and 199 mL of distilled water only. : The root extract of S. isoetifolium showed maximum larvicidal activity with minimum concentration of extract of LC50= 0.0 604 ± 0.0 040)µg/mL with lower confidence limit (LCL) - upper confidence limit (UCL) = (0.051-0.071) and LC90=0.0 972µg/mL followed by leaf extract of S. isoetifolium showed LC50= (0.062 ± 0.005)µg/mL. The regression equation of root and leaf extract of S. isoetifolium for 4th instar larvae were Y= 4.909 + 1.32x (R(2)= 0.909) and Y= 2.066 + 1.21x (R(2) =0.897) respectively. The results of the preliminary phytochemical constituents shows the presence of saponin, steroids, terpenoid, phenols, protein and sugars. From the present study the ethanolic extracts of seagrass of S. isoetifolium possesses lead compound for development of larvicidal activity.

  7. Bioactivity of seagrass against the dengue fever mosquito Aedes aegypti larvae

    PubMed Central

    Ali, M Syed; Ravikumar, S; Beula, J Margaret

    2012-01-01

    Objective To identify the larvicidal activity of the seagrass extracts. Methods Seagrass extracts, Syringodium isoetifolium (S. isoetifolium), Cymodocea serrulata and Halophila beccarii, were dissolved in DMSO to prepare a graded series of concentration. Batches of 25 early 4th instars larvae of Aedes aegypti (Ae. aegypti) were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (0.01 mg – 0.1 mg). After 24 h the mortality rate was identified with the formulae [(% of test mortality – % of control mortality)/(100 – % of control mortality)] × 100. Each experiment was conducted with three replicates and a concurrent control group. A control group consisted of 1 mL of DMSO and 199 mL of distilled water only. Results : The root extract of S. isoetifolium showed maximum larvicidal activity with minimum concentration of extract of LC50= 0.0 604 ± 0.0 040)µg/mL with lower confidence limit (LCL) – upper confidence limit (UCL) = (0.051–0.071) and LC90=0.0 972µg/mL followed by leaf extract of S. isoetifolium showed LC50= (0.062 ± 0.005)µg/mL. The regression equation of root and leaf extract of S. isoetifolium for 4th instar larvae were Y= 4.909 + 1.32x (R2= 0.909) and Y= 2.066 + 1.21x (R2 =0.897) respectively. The results of the preliminary phytochemical constituents shows the presence of saponin, steroids, terpenoid, phenols, protein and sugars. Conclusions From the present study the ethanolic extracts of seagrass of S. isoetifolium possesses lead compound for development of larvicidal activity. PMID:23569973

  8. Effect of mycosynthesized silver nanoparticles from filtrate of Trichoderma harzianum against larvae and pupa of dengue vector Aedes aegypti L.

    PubMed

    Sundaravadivelan, Chandran; Padmanabhan, Madanagopal Nalini

    2014-03-01

    Mosquitoes transmit dreadful diseases, causing millions of deaths every year. Therefore, screening for larvicidal and pupicidal activity of microbial extracts attributes could lead to development of new and improved mosquito control methods that are economical and safe for nontarget organisms and are ecofriendly. Synthetic chemical insecticides occupy predominant position in control strategies. These hazardous chemicals exert unwarranted toxicity and lethal effects on nontarget organisms, develop physiological resistance in target, and cause adverse environmental effect. For vector control, fungal-mediated natural products have been a priority in this area at present. In the current study, effective larvicidal and pupicidal effect of mycosynthesized silver nanoparticles (Ag NPs) using an entomopathogenic fungi Trichoderma harzianum against developmental stages of the dengue vector Aedes aegypti was investigated. An attractive possibility of green nanotechnology is to use microorganisms in the synthesis of nanosilver especially Ag NPs. The mycosynthesized Ag NPs were characterized to find their unique properties through UV-visible spectrophotometer, X-ray diffraction analysis, Fourier transform infrared, and surface characteristics by scanning electron microscopy. To analyze the bioefficacy, different test concentrations for extracellular filtrate (0.2, 0.4, 0.6, 0.8, and 1.0 %) and Ag NPs (0.05, 0.10, 0.15, 0.20, and 0.25 %) were prepared to a final volume of 200 mL using deionized water; 20 larvae of each instars (I-IV) and pupa were exposed to each test concentration separately which included a set of control (distilled water) group with five replicates. Characterization of the synthesized Ag NPs were about 10-20 nm without aggregation. Susceptibility of larval instars to synthesized Ag NPs was higher than the extracellular filtrate of T. harzianum alone after 24-h exposure, where the highest mortality was recorded as 92 and 96 % for first and second instars and

  9. Mechanistic basis for morphological damage induced by essential oil from Brazilian pepper tree, Schinus terebinthifolia, on larvae of Stegomyia aegypti, the dengue vector.

    PubMed

    Pratti, Drielle L A; Ramos, Alessandro C; Scherer, Rodrigo; Cruz, Zilma M A; Silva, Ary G

    2015-03-01

    Dengue has become the subject of public health programs worldwide. The lack of a vaccine and the high environmental risk of synthetic insecticides, arouse the interest in natural products against this vector. This study aimed to determine the chemical composition of the essential oil of ripe fruits and seeds of Schinus terebinthifolia Raddi; to evaluate the essential oil effect on mortality of Stegomyia aegypti (Linnaeus, 1792) larvae; and to characterize the structural damage suffered by larvae and their association with different contents of essential oil. Ripe fruits and seeds were crunched and their essential oil was extracted through hydrodistillation, purified, and its phytochemical analysis was carried out through High Resolution Gas Chromatography, coupled with Mass Spectrometry. This essential oil was diluted in a 10-point gradient of 86.22 - 862.20 ppm, at regular intervals of 86.22 ppm. Each point received 50 larvae and the assessments of surviving were made at 24, 48 and 72 hours after inoculation. Structural damage was assessed through measurements of thickness with exoskeleton, evaluating the integrity of the head, thorax, abdominal segments, and air siphon, using ImageJ software. Statistical data analysis was carried out through Logistic Regression and Discriminant Analysis. 56 substances were identified, corresponding to 81.67% of the essential oil composition. Larvae were dose-dependent susceptible to the essential oil; the concentration produced a significant effect on larval mortality. Among the major deformations found in the larvae, it was detected inhibition of chitin synthesis by the activity of the oil, thus reducing the deposition of cuticle layers. The essential oil caused death in exposed larvae after 72 hours, in a dose-dependent manner. It also changed the structure of exposed larvae, indicating a direct effect on larval exoskeleton. The results open up possibilities for the use of natural products as an alternative to control dipterans.

  10. Selective Tidal Stream Transport of Flounder Larvae ( Platichthys flesusL.) in the Dollard (Ems Estuary)

    NASA Astrophysics Data System (ADS)

    Jager, Z.

    1999-09-01

    The vertical distribution of flounder larvae (Platichthys flesus L.) was investigated in the Dollard (Ems estuary, Wadden Sea) in relation to tidal phase and physical variables in order to address the question whether larval migration into the nursery is accomplished by passive transport, or is influenced by active (swimming) behaviour. Larval concentrations were measured twice per hour simultaneously at three water depths from low water (LW), through high water (HW), to the next LW slack. Physical variables were measured at the same time. Maximum concentrations of flounder larvae were 433 m-3in 1994 and 40 m-3in 1995. There were tidal variations in larval concentrations in all three water layers and the vertical distribution varied as well. The highest larval concentrations were usually found near the surface during flood and the lowest in the midwater layer during the ebb. In contrast to larval concentrations, turbidity was always highest near the bottom. The observation that larval vertical distributions deviate from those of suspended matter and vary in a different way led to the rejection of an entirely passive transport mechanism. The vertical distribution of larvae during flood supported the selective tidal stream transport hypothesis, but the relatively high number of flounder larvae in the surface layer during ebb was in contradiction with it. The high surface concentrations during ebb may have been caused by different origins of the water layers and thus larvae, or by an inability of the metamorphosing larvae to resist the strong ebb currents. The data suggest that the transport process inside the nursery may favour retention.

  11. Integrated process for the purification and immobilization of the envelope protein domain III of dengue virus type 2 expressed in Rachiplusia nu larvae and its potential application in a diagnostic assay.

    PubMed

    Smith, María Emilia; Targovnik, Alexandra Marisa; Cerezo, Julieta; Morales, María Alejandra; Miranda, María Victoria; Talou, Julián Rodríguez

    2016-11-23

    Dengue incidence has grown dramatically in the last years, with about 40% of the world population at risk of infection. Recently, a vaccine developed by Sanofi Pasteur has been registered, but only in a few countries. Moreover, specific antiviral drugs are not available. Thus, an efficient and accurate diagnosis is important for disease management. To develop a low-cost immunoassay for dengue diagnosis, in the present study we expressed the envelope protein domain III of dengue virus type 2 in Rachiplusia nu larvae by infection with a recombinant baculovirus. The antigen was expressed as a fusion to hydrophobin I (DomIIIHFBI) to easily purify it by an aqueous two-phase system (ATPS) and to efficiently immobilize it in immunoassay plates. A high level of recombinant DomIIIHFBI was obtained in R. nu, where yields reached 4.5 mg per g of larva. Also, we were able to purify DomIIIHFBI by an ATPS with 2% of Triton X-114, reaching a yield of 73% and purity higher than 80% in a single purification step. The recombinant DomIIIHFBI was efficiently immobilized in hydrophobic surface plates. The immunoassay we developed with the immobilized antigen was able to detect IgG specific for dengue virus type 2 in serum samples and not for other serotypes.

  12. Dengue and Severe Dengue

    MedlinePlus

    ... serotypes increase the risk of developing severe dengue. Global burden of dengue The incidence of dengue has ... accumulation, respiratory distress, severe bleeding, or organ impairment. Warning signs occur 3–7 days after the first ...

  13. Detection of dengue virus in platelets isolated from dengue patients.

    PubMed

    Noisakran, Sansanee; Gibbons, Robert V; Songprakhon, Pucharee; Jairungsri, Aroonroong; Ajariyakhajorn, Chuanpis; Nisalak, Ananda; Jarman, Richard G; Malasit, Prida; Chokephaibulkit, Kulkanya; Perng, Guey Chuen

    2009-03-01

    Though thrombocytopenia or dysfunction of platelets is common in dengue virus infection, the role of platelets has not been established. We enrolled 33 hospitalized children with serologically confirmed dengue virus infection. Blood specimens were collected during hospitalization. Platelets and plasma were isolated from the whole blood. Detection of dengue virus in plasma and platelets was carried out by RT-PCR with primers that can differentiate different dengue serotypes simultaneously, and by electron transmission microscopy (EM). Dengue viral RNA was detected in the platelets and plasma by conventional RT-PCR. A significantly higher percentage of dengue viral RNA was detected in platelets than in plasma (p = 0.03). Platelets isolated 5 days after onset of fever were most likely positive for viral RNA. Concurrent infection or co-circulation with multiple dengue serotypes was observed in 12% of patients. Infrequently, negative-stranded dengue viral RNA was detected in platelets and in plasma. Importantly, EM confirmed the presence of dengue viral-like particles inside platelets prepared from dengue patients. Our findings suggest the presence of dengue virus in platelets may be associated with the dysfunction of platelets observed in dengue patients.

  14. Accumulation of flounder larvae ( Platichthys flesus L.) in the Dollard (Ems estuary, Wadden Sea)

    NASA Astrophysics Data System (ADS)

    Jager, Zwanette

    1998-09-01

    In the context of an investigation of the importance of the Dollard as a nursery for flounder ( Platichthys flesus L.), the process of larval accumulation was studied. The hypothesis was addressed that freshwater discharge is a steering factor in larval transport caused by a larval preference for low-salinity water. Flounder larvae were simultaneously sampled at three locations during five tidal cycles in combination with measurements of physical variables. One location was in the main channel, the other two were in more peripheral channels of the Dollard. One of those is directly connected to a sluice by which freshwater is discharged into the Dollard. Concentrations of larvae varied during the tidal cycle at all locations: high initial values dropped after the middle of the flood to lower levels to increase again at the end of the ebb. In the channel connected to the sluice, significantly lower salinities were observed around low water than at the other locations, which coincided with significantly higher larval concentrations at the beginning of flood. Water transport as well as larval transport at this location showed a flood surplus on all sampling dates. Also, relatively more larvae were transported than expected according to the water transport compared to the other stations. Moreover, there was an ebb surplus in larval transport during some sampling dates at the other locations. The results indicated an accumulation of flounder larvae in the inner Dollard, and particularly in the area affected by the discharge of freshwater. Independent observations of settling flounder larvae in traps also indicated a concentration in the vicinity of the sluice. However, the sluice itself may form an effective barrier for flounder larvae that try to migrate to freshwater.

  15. Transport Velocity of Flounder Larvae ( Platichthys flesus L.) in the Dollard (Ems Estuary)

    NASA Astrophysics Data System (ADS)

    Jager, Z.; Mulder, H. P. J.

    1999-09-01

    Larval concentrations of flounder (Platichthys flesus L.), longitudinal current velocity and physical variables were measured simultaneously in the Dollard to calculate the mass transport of the larvae, salinity and suspended matter. Transport velocities of the three substances (salinity, suspended matter and larvae) and of water were calculated and compared. The concept of larval velocity was extended to incorporate the effect of varying vertical larval distribution. The contributions of variations in vertical and temporal concentration to the transport velocity were calculated separately. The differences in velocity between the substances in relation to the vertical and temporal variation provide more insight in estuarine transport processes in the nursery. Temporal salinity variation dominated over vertical variation during flood, and indicated that longitudinal advection was important. Overall, during flood the transport velocity of salinity was 3% lower than that of water. During ebb, there was hardly any difference between the transport velocity of salinity and water. The contributions of temporal and vertical variation in suspended matter were each in the order of 10%, but of opposite signs. The net result is a transport velocity of suspended matter which is 3% (flood) or 4% (ebb) higher than that of water. Erosion-deposition seemed the dominant process. During flood, transport velocity of larvae is 9% higher than that of water, which is mainly caused by vertical concentration variation (6%), while during ebb, larval transport velocity is 9% lower, which is almost exclusively due to the temporal concentration variation (8%). Swimming influences transport during flood, while during ebb it is not clear which process dominates. The results indicate that flounder larvae make use of selective tidal stream transport inside the nursery.

  16. Dengue encephalitis

    PubMed Central

    Borawake, Kapil; Prayag, Parikshit; Wagh, Atul; Dole, Swati

    2011-01-01

    We report a case of dengue fever with features of encephalitis. The diagnosis of dengue was confirmed by the serum antibodies to dengue and the presence of a dengue antigen in the cerebrospinal fluid. This patient had characteristic magnetic resonance imaging brain findings, mainly involving the bilateral thalami, with hemorrhage. Dengue is not primarily a neurotropic virus and encephalopathy is a common finding in Dengue. Hence various other etiological possibilities were considered before concluding this as a case of Dengue encephalitis. This case explains the importance of considering the diagnosis of dengue encephalitis in appropriate situations. PMID:22013316

  17. Transport and retention of flounder larvae ( Platichthys flesus L.) in the Dollard nursery (Ems estuary)

    NASA Astrophysics Data System (ADS)

    Jager, Zwanette

    2001-05-01

    Variability in tidal transport of larval flounder ( Platichthys flesus L.) in the Dollard was investigated to estimate the quantity of larvae that are annually retained in the nursery based on simultaneous measurements of water transport and larval concentrations. Sampling was done three times per hour in the main channel in the Dollard, during 35 tidal cycles divided over 1993, 1994 and 1995. In 1993, additional sampling was carried out simultaneously during eight tidal cycles in a subsidiary channel. Larval concentrations showed marked tidal variations at all time scales and indicated a patchy spatial distribution. The estimated net tidal transport of larvae was not correlated to the net tidal transport of water. However, a higher net water transport coincided with higher retention, defined as the percentage of net larval transport divided by the flood larval transport. Also, relatively longer duration of the flood than the ebb period (tidal asymmetry) was positively correlated with both net tidal water transport and larval retention. The wind direction significantly affected the net water transport at the cross-section in the main channel, whereas wind speed was not significant. The flood transport, but not the ebb or net transport, was significantly higher during spring tide following full moon than during the other lunar phases. The net tidal transport of larvae was much more variable in 1994 than in 1993 and 1995, frequently resulting in ebb surpluses in larval transport. Despite higher mean concentrations, the estimated net larval input was lower in 1994 than in 1993. This corresponded neither with the observed abundance estimates of juvenile flounder in the Dollard in these two years, nor with the abundance index obtained from routine surveys. The total larval input better reflects the juvenile flounder abundance. Variability in water circulation, influenced by varying wind conditions, and its effect on larval transport and retention is an important source

  18. Dengue Fever

    MedlinePlus

    ... away from areas that have a dengue fever epidemic, the risk of contracting dengue fever is small for international travelers./p> Reviewed by: Elana ... Transfusions Cholera West Nile Virus First Aid: Vomiting Are Insect ...

  19. Expanded Dengue.

    PubMed

    Kadam, D B; Salvi, Sonali; Chandanwale, Ajay

    2016-07-01

    The World Health Organization (WHO) has coined the term expanded dengue to describe cases which do not fall into either dengue shock syndrome or dengue hemorrhagic fever. This has incorporated several atypical findings of dengue. Dengue virus has not been enlisted as a common etiological agent in several conditions like encephalitis, Guillain Barre syndrome. Moreover it is a great mimic of co-existing epidemics like Malaria, Chikungunya and Zika virus disease, which are also mosquito-borne diseases. The atypical manifestations noted in dengue can be mutisystemic and multifacetal. In clinical practice, the occurrence of atypical presentation should prompt us to investigate for dengue. Knowledge of expanded dengue helps to clinch the diagnosis of dengue early, especially during ongoing epidemics, avoiding further battery of investigations. Dengue has proved to be the epidemic with the ability to recur and has a diverse array of presentation as seen in large series from India, Srilanka, Indonesia and Taiwan. WHO has given the case definition of dengue fever in their comprehensive guidelines. Accordingly, a probable case is defined as acute febrile illness with two or more of any findings viz. headache, retro-orbital pain, myalgia, arthralgia, rash, hemorrhagic manifestations, leucopenia and supportive serology. There have been cases of patients admitted with fever, altered mentation with or without neck stiffness and pyramidal tract signs. Some had seizures or status epilepticus as presentation. When they were tested for serology, dengue was positive. After ruling out other causes, dengue remained the only culprit. We have come across varied presentations of dengue fever in clinical practice and the present article throws light on atypical manifestations of dengue. © Journal of the Association of Physicians of India 2011.

  20. [Autochthonous dengue].

    PubMed

    Sorge, F; Minodier, P; Velayudhan-Deschamps, N

    2016-12-01

    Dengue is the arboviral disease that has massively spread in intertropical regions these past few years. The rise in imported cases of dengue and the rapid spread of the Aedes vector mosquitoes in continental France since 2004 explain the occurrence of indigenous dengue cases among the nonimmune population and points to an epidemic risk. Severe dengue cases are rare, but lethality is highest among children under 5 years of age. Like pediatricians in tropical regions, we must learn how dengue presents in metropolitan France and how it can be managed, and pay special attention to severe and potentially fatal forms. The epidemiological, pathophysiological, clinical, diagnostic, and therapeutic characteristics of dengue are presented herein. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. Dengue and Dengue Hemorrhagic Fever

    PubMed Central

    Gubler, Duane J.

    1998-01-01

    Dengue fever, a very old disease, has reemerged in the past 20 years with an expanded geographic distribution of both the viruses and the mosquito vectors, increased epidemic activity, the development of hyperendemicity (the cocirculation of multiple serotypes), and the emergence of dengue hemorrhagic fever in new geographic regions. In 1998 this mosquito-borne disease is the most important tropical infectious disease after malaria, with an estimated 100 million cases of dengue fever, 500,000 cases of dengue hemorrhagic fever, and 25,000 deaths annually. The reasons for this resurgence and emergence of dengue hemorrhagic fever in the waning years of the 20th century are complex and not fully understood, but demographic, societal, and public health infrastructure changes in the past 30 years have contributed greatly. This paper reviews the changing epidemiology of dengue and dengue hemorrhagic fever by geographic region, the natural history and transmission cycles, clinical diagnosis of both dengue fever and dengue hemorrhagic fever, serologic and virologic laboratory diagnoses, pathogenesis, surveillance, prevention, and control. A major challenge for public health officials in all tropical areas of the world is to devleop and implement sustainable prevention and control programs that will reverse the trend of emergent dengue hemorrhagic fever. PMID:9665979

  2. Analysis of dengue fever risk using geostatistics model in bone regency

    NASA Astrophysics Data System (ADS)

    Amran, Stang, Mallongi, Anwar

    2017-03-01

    This research aim is to analysis of dengue fever risk based on Geostatistics model in Bone Regency. Risk levels of dengue fever are denoted by parameter of Binomial distribution. Effect of temperature, rainfalls, elevation, and larvae abundance are investigated through Geostatistics model. Bayesian hierarchical method is used in estimation process. Using dengue fever data in eleven locations this research shows that temperature and rainfall have significant effect of dengue fever risk in Bone regency.

  3. Dengue fever.

    PubMed

    Skinner, Anita

    Dengue fever is a notifiable infectious disease in England because of its geographic expansion and the increase in the number of epidemics. The article highlighted the importance of informing overseas travellers of the risk of acquiring dengue fever and advising them on personal protective measures.

  4. Dengue Fever Treatment

    MedlinePlus

    ... linkedin Dengue Fever Treatment Dengue Fever Dengue Fever Biology and Transmission Prevention Diagnosis Treatment Featured Research NIAID- ... last reviewed on February 8, 2011 Dengue Fever Biology and Transmission Prevention Diagnosis Treatment Featured Research ^ Return ...

  5. DENGUE VACCINES.

    PubMed

    Thisyakorn, Usa; Thisyakorn, Chule

    2015-01-01

    The uniqueness of the dengue viruses (DENVs) and the spectrum of disease resulting from infection have made dengue vaccine development difficult. Several vaccine candidates are currently being evaluated in clinical studies. The candidate currently at the most advanced clinical development stage, a live-attenuated tetravalent vaccine based on the chimeric yellow fever-dengue virus (CYD-TDV), has progressed to Phase 3 efficacy studies. Several other live-attenuated vaccines, as well as subunit, DNA, and purified inactivated vaccine candidates are at earlier stages of clinical development. Additional technological approaches, such as virus-vectored and Virus-Like Particles (VLP)-based vaccines are under evaluation in preclinical studies.

  6. Dengue Epidemiology

    MedlinePlus

    ... Address What's this? Submit What's this? Submit Button ... fever (DF) is caused by any of four closely related viruses, or serotypes: dengue 1-4. Infection with one serotype does not protect against the ...

  7. Prediction of protein-protein interactions in dengue virus coat proteins guided by low resolution cryoEM structures

    PubMed Central

    2010-01-01

    Background Dengue virus along with the other members of the flaviviridae family has reemerged as deadly human pathogens. Understanding the mechanistic details of these infections can be highly rewarding in developing effective antivirals. During maturation of the virus inside the host cell, the coat proteins E and M undergo conformational changes, altering the morphology of the viral coat. However, due to low resolution nature of the available 3-D structures of viral assemblies, the atomic details of these changes are still elusive. Results In the present analysis, starting from Cα positions of low resolution cryo electron microscopic structures the residue level details of protein-protein interaction interfaces of dengue virus coat proteins have been predicted. By comparing the preexisting structures of virus in different phases of life cycle, the changes taking place in these predicted protein-protein interaction interfaces were followed as a function of maturation process of the virus. Besides changing the current notion about the presence of only homodimers in the mature viral coat, the present analysis indicated presence of a proline-rich motif at the protein-protein interaction interface of the coat protein. Investigating the conservation status of these seemingly functionally crucial residues across other members of flaviviridae family enabled dissecting common mechanisms used for infections by these viruses. Conclusions Thus, using computational approach the present analysis has provided better insights into the preexisting low resolution structures of virus assemblies, the findings of which can be made use of in designing effective antivirals against these deadly human pathogens. PMID:20550721

  8. Dengue vaccines: implications for dengue control.

    PubMed

    Robinson, Matthew L; Durbin, Anna P

    2017-10-01

    Dengue, the most common arbovirus, is an increasingly significant cause of morbidity worldwide. After decades of research, an approved tetravalent dengue vaccine is finally available. Models constructed using recently available vaccine efficacy data allow for a data-driven discussion of the potential impact of dengue vaccine deployment on global control. Phase 3 efficacy trials demonstrated that the approved dengue vaccine, chimeric yellow fever-dengue-tetravalent dengue vaccine, has an efficacy of 60% against dengue illness of any severity. However, among dengue unexposed recipients, vaccination offers limited efficacy and may increase dengue severity. The WHO consequently recommends dengue vaccination for populations in which 70% of intended recipients are dengue seropositive. Models predict that routine childhood dengue vaccine may reduce dengue burden, but over time, population-level impact may be limited. Additional vaccine candidates in late-stage development may not suffer from the same limitations as chimeric yellow fever-dengue-tetravalent dengue vaccine. The efficacy and safety profile of the recently approved dengue vaccine is favorable only in previously dengue exposed recipients, which limits its potential for global control. Future work must evaluate the approved vaccine's long-term durability, efficacy of other late phase vaccine candidates, and potential for vector control efforts to work synergistically with vaccine deployment.

  9. Distribution, seasonal variation & dengue transmission prediction in Sisaket, Thailand

    PubMed Central

    Wongkoon, S.; Jaroensutasinee, M.; Jaroensutasinee, K.

    2013-01-01

    Background & objectives: Environmental factors including weather variables may play a significant role in the transmission of dengue. This study investigated the effect of seasonal variation on the abundance of Aedes aegypti and Ae. albopictus larvae and explored the impact of weather variability on dengue transmission in Sisaket, Thailand. Methods: The monthly mosquito larval surveys were carried out in urban and rural areas in Sisaket, Thailand from January to December 2010. Data on monthly-reported cases of dengue fever over the period 2004-2010 were obtained from the Ministry of Public Health. Weather data over the same period were obtained from the Thai Meteorological Department. Chi-square test was used to find the differences relating to seasonal variability, areas of study, and mosquito species factors using entomological survey data. Time series Poisson regression analysis was performed using data on monthly weather variables and dengue cases. Results: There were more Ae. aegypti larvae per household than Ae. albopictus larvae in the winter and rainy seasons. More Aedes larvae per household were found in the rainy season than in the winter and summer seasons. Relative humidity at a lag of one month and rainy days in the current month were significant predictors of dengue incidence in Sisaket. Interpretation & conclusions: Increased rain during the current month and less humidity during the previous month might trigger a higher incidence of dengue epidemic in Sisaket. The present findings suggest that the dengue incidence corresponds with the number of Aedes larvae. The seasonal patterns of dengue outbreaks coincide with the rainy season. PMID:24135179

  10. Aedes aegypti Global Suitability Maps Using a Water Container Energy Balance Model for Dengue Risk Applications

    NASA Astrophysics Data System (ADS)

    Steinhoff, D.

    2015-12-01

    Dengue infections are estimated to total nearly 400 million per year worldwide, with both the geographic range and the magnitude of infections having increased in the past 50 years. The primary dengue vector mosquito Aedes aegypti is closely associated with humans. It lives exclusively in urban and semi-urban areas, preferentially bites humans, and spends its developmental stages in artificial water containers. Climate regulates the development of Ae. aegypti immature mosquitoes in artificial containers. Potential containers for Ae. aegypti immature development include, but are not limited to, small sundry items (e.g., bottles, cans, plastic containers), buckets, tires, barrels, tanks, and cisterns. Successful development of immature mosquitoes from eggs to larvae, pupae, and eventually adults is largely dependent on the availability of water and the thermal properties of the water in the containers. Recent work has shown that physics-based approaches toward modeling container water properties are promising for resolving the complexities of container water dynamics and the effects on immature mosquito development. An energy balance container model developed by the author, termed the Water Height And Temperature in Container Habitats Energy Model (WHATCH'EM), solves for water temperature and height for user-specified containers with readily available weather data. Here we use WHATCH'EM with NASA Earth Science products used as input to construct global suitability maps based on established water temperature ranges for immature Ae. aegypti mosquitoes. A proxy for dengue risk is provided from habitat suitability, but also population estimates, as Ae. aegypti is closely associated with human activity. NASA gridded Global Population of the World data is used to mask out rural areas with low dengue risk. Suitability maps are illustrated for a variety of containers (size, material, color) and shading scenarios.

  11. Effect of dengue-1 antibodies on American dengue-2 viral infection and dengue haemorrhagic fever.

    PubMed

    Kochel, Tadeusz J; Watts, Douglas M; Halstead, Scott B; Hayes, Curtis G; Espinoza, Angelica; Felices, Vidal; Caceda, Roxana; Bautista, Christian T; Montoya, Ysabel; Douglas, Susan; Russell, Kevin L

    2002-07-27

    In Iquitos, Peru, no cases of dengue haemorrhagic fever have been recorded in individuals infected with dengue-1 virus followed by American genotype dengue-2 (American dengue-2) virus. We assayed serum samples collected in Iquitos that tested positive for antibodies of monotype dengue-1 and monotype dengue-2 using a plaque reduction neutralisation test to determine their ability to neutralise the infectivity of two dengue-1 viruses, two American dengue-2 viruses, and two Asian dengue-2 viruses. Sera positive for the dengue-1 antibody neutralised dengue-1 viruses and American dengue-2 viruses much more effectively than Asian dengue-2 viruses. Neutralisation of American dengue-2 virus by sera positive for dengue-1 antibodies may account for the absence of dengue haemorrhagic fever in individuals infected with dengue-1 in 1990-91 followed by American dengue-2 virus in 1995 in Iquitos, Peru.

  12. Multiple dengue virus types harbored by individual mosquitoes.

    PubMed

    Angel, Bennet; Angel, Annette; Joshi, Vinod

    2015-10-01

    The existing knowledge on pathogenesis and aetiology of DHF establishes that Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS) are caused by two subsequent infections of two different serotypes of dengue affecting a common human population with a time gap. Present studies have been undertaken on 212 laboratory reared infected individual mosquitoes from larvae collected from 31 dengue endemic towns of Rajasthan, India. Type specific DEN viruses were detected from individual mosquitoes employing RT-PCR. In 78.7% of 212 infected individual mosquitoes studied, vertically transmitted multiple DENV types were observed. We report for the first time that single mosquitoes contain multiple dengue virus types. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Hypokalemic quadriparesis in dengue.

    PubMed

    Mishra, Vikas; Harbada, Rishit; Sharma, Akhilesh; Mishra, Meenakshi

    2015-01-01

    Dengue infection is the leading cause of illness and death in tropical and subtropical regions of the world. The common complications associated with dengue fever are usual hematological abnormalities, shock, and organ failure. The neurological complications of dengue are uncommon. However, evidence of dengue virus neurotropism and complications has been slowly but surely rising as seen from increased literature on this subject over the last decade. We report an uncommon case of hypokalemic quadriparesis with dengue that had a favorable outcome.

  14. [Larva migrans].

    PubMed

    Chabasse, D; Le Clec'h, C; de Gentile, L; Verret, J L

    1995-01-01

    Larbish, cutaneous larva migrans or creeping eruption, is a serpiginous cutaneous eruption caused by skin penetration of infective larva from various animal nematodes. Hookworms (Ancylostoma brasiliense, A. caninum) are the most common causative parasites. They live in the intestines of dogs and cats where their ova are deposited in the animal feces. In sandy and shady soil, when temperature and moisture are elevated, the ova hatch and mature into infective larva. Infection occurs when humans have contact with the infected soil. Infective larva penetrate the exposed skin of the body, commonly around the feet, hands and buttocks. In humans, the larva are not able to complete their natural cycle and remain trapped in the upper dermis of the skin. The disease is widespread in tropical or subtropical regions, especially along the coast on sandy beaches. The diagnosis is easy for the patient who is returning from a tropical or subtropical climate and gives a history of beach exposure. The characteristic skin lesion is a fissure or erythematous cord which is displaced a few millimeters each day in a serpiginous track. Scabies, the larva currens syndrome due to Strongyloides stercoralis, must be distinguished from other creeping eruptions and subcutaneous swelling lesions caused by other nematodes or myiasis. Medical treatments are justified because it shortens the duration of the natural evolution of the disease. Topical tiabendazole is safe for localized invasions, but prolonged treatment may be necessary. Oral thiabendazole treatment for three days is effective, but sometimes is associated with adverse effects. Trials using albendazole for one or four consecutive days appear more efficacious. More recent trials using ivermectine showed that a single oral dose can cure 100% of the patients; thus, this drug looks very promising as a new form of therapy. Individual prophylaxis consists of avoiding skin contact with soil which has been contaminated with dog or cat feces

  15. Dengue Knowledge and Preventive Practices in Iquitos, Peru

    PubMed Central

    Paz-Soldán, Valerie A.; Morrison, Amy C.; Cordova Lopez, Jhonny J.; Lenhart, Audrey; Scott, Thomas W.; Elder, John P.; Sihuincha, Moises; Kochel, Tadeusz J.; Halsey, Eric S.; Astete, Helvio; McCall, Philip J.

    2015-01-01

    As part of a cluster-randomized trial to evaluate insecticide-treated curtains for dengue prevention in Iquitos, Peru, we surveyed 1,333 study participants to examine knowledge and reported practices associated with dengue and its prevention. Entomological data from 1,133 of these households were linked to the survey. Most participants knew that dengue was transmitted by mosquito bite (85.6%), but only few (18.6%) knew that dengue vectors bite during daytime. Most commonly recognized dengue symptoms were fever (86.6%), headache (76.4%), and muscle/joint pain (67.9%). Most commonly reported correct practices for mosquito control were cleaning homes (61.6%), using insecticide sprays (23%), and avoiding having standing water at home (12.3%). Higher education was associated with higher knowledge about dengue, including transmission and vector control. Higher socioeconomic status was associated with increased reported use of preventive practices requiring money expenditure. We were less likely to find Aedes aegypti eggs, larvae, or pupae in households that had < 5-year-old children at home. Although dengue has been transmitted in Iquitos since the 1990s and the Regional Health Authority routinely fumigates households, treats domestic water containers with larvicide, and issues health education messages through mass media, knowledge of dengue transmission and household practices for prevention could be improved. PMID:26503276

  16. Dengue Knowledge and Preventive Practices in Iquitos, Peru.

    PubMed

    Paz-Soldán, Valerie A; Morrison, Amy C; Cordova Lopez, Jhonny J; Lenhart, Audrey; Scott, Thomas W; Elder, John P; Sihuincha, Moises; Kochel, Tadeusz J; Halsey, Eric S; Astete, Helvio; McCall, Philip J

    2015-12-01

    As part of a cluster-randomized trial to evaluate insecticide-treated curtains for dengue prevention in Iquitos, Peru, we surveyed 1,333 study participants to examine knowledge and reported practices associated with dengue and its prevention. Entomological data from 1,133 of these households were linked to the survey. Most participants knew that dengue was transmitted by mosquito bite (85.6%), but only few (18.6%) knew that dengue vectors bite during daytime. Most commonly recognized dengue symptoms were fever (86.6%), headache (76.4%), and muscle/joint pain (67.9%). Most commonly reported correct practices for mosquito control were cleaning homes (61.6%), using insecticide sprays (23%), and avoiding having standing water at home (12.3%). Higher education was associated with higher knowledge about dengue, including transmission and vector control. Higher socioeconomic status was associated with increased reported use of preventive practices requiring money expenditure. We were less likely to find Aedes aegypti eggs, larvae, or pupae in households that had < 5-year-old children at home. Although dengue has been transmitted in Iquitos since the 1990s and the Regional Health Authority routinely fumigates households, treats domestic water containers with larvicide, and issues health education messages through mass media, knowledge of dengue transmission and household practices for prevention could be improved. © The American Society of Tropical Medicine and Hygiene.

  17. Dengue viral infections

    PubMed Central

    Malavige, G; Fernando, S; Fernando, D; Seneviratne, S

    2004-01-01

    Dengue viral infections are one of the most important mosquito borne diseases in the world. They may be asymptomatic or may give rise to undifferentiated fever, dengue fever, dengue haemorrhagic fever (DHF), or dengue shock syndrome. Annually, 100 million cases of dengue fever and half a million cases of DHF occur worldwide. Ninety percent of DHF subjects are children less than 15 years of age. At present, dengue is endemic in 112 countries in the world. No vaccine is available for preventing this disease. Early recognition and prompt initiation of appropriate treatment are vital if disease related morbidity and mortality are to be limited. This review outlines aspects of the epidemiology of dengue infections, the dengue virus and its mosquito vector, clinical features and pathogenesis of dengue infections, and the management and control of these infections. PMID:15466994

  18. The dengue viruses.

    PubMed Central

    Henchal, E A; Putnak, J R

    1990-01-01

    Dengue, a major public health problem throughout subtropical and tropical regions, is an acute infectious disease characterized by biphasic fever, headache, pain in various parts of the body, prostration, rash, lymphadenopathy, and leukopenia. In more severe or complicated dengue, patients present with a severe febrile illness characterized by abnormalities of hemostasis and increased vascular permeability, which in some instances results in a hypovolemic shock. Four distinct serotypes of the dengue virus (dengue-1, dengue-2, dengue-3, and dengue-4) exist, with numerous virus strains found worldwide. Molecular cloning methods have led to a greater understanding of the structure of the RNA genome and definition of virus-specific structural and nonstructural proteins. Progress towards producing safe, effective dengue virus vaccines, a goal for over 45 years, has been made. Images PMID:2224837

  19. Dengue fever (image)

    MedlinePlus

    Dengue fever, or West Nile fever, is a mild viral illness transmitted by mosquitoes which causes fever, ... second exposure to the virus can result in Dengue hemorrhagic fever, a life-threatening illness.

  20. Dengue reemergence in Argentina.

    PubMed Central

    Avilés, G.; Rangeón, G.; Vorndam, V.; Briones, A.; Baroni, P.; Enria, D.; Sabattini, M. S.

    1999-01-01

    Aedes aegypti, eradicated from Argentina in 1963, has now reinfested the country as far south as Buenos Aires. In 1997, four persons with travel histories to Brazil, Ecuador, or Venezuela had confirmed dengue, and surveillance for indigenous transmission allowed the detection of 19 dengue cases in Salta Province. These cases of dengue are the first in Argentina since 1916 and represent a new southern extension of dengue virus. PMID:10460181

  1. Dengue reemergence in Argentina.

    PubMed

    Avilés, G; Rangeón, G; Vorndam, V; Briones, A; Baroni, P; Enria, D; Sabattini, M S

    1999-01-01

    Aedes aegypti, eradicated from Argentina in 1963, has now reinfested the country as far south as Buenos Aires. In 1997, four persons with travel histories to Brazil, Ecuador, or Venezuela had confirmed dengue, and surveillance for indigenous transmission allowed the detection of 19 dengue cases in Salta Province. These cases of dengue are the first in Argentina since 1916 and represent a new southern extension of dengue virus.

  2. Human and mosquito infections by dengue viruses during and after epidemics in a dengue-endemic region of Colombia.

    PubMed

    Méndez, Fabián; Barreto, Mauricio; Arias, Juan F; Rengifo, Graciela; Muñoz, Jaime; Burbano, María E; Parra, Beatriz

    2006-04-01

    We conducted a study in a dengue-endemic area of Colombia to evaluate the dynamics of transmission of dengue viruses during and after epidemics. Information was simultaneously gathered about occurrence of infection in humans and mosquitoes every three months in four cities with endemic transmission. Viral isolation was confirmed in 6.7% of the persons and most were asymptomatic. Adult mosquito and larvae house indexes were not found associated with increased burden of disease. The only entomologic indicator related to dengue infection in humans was the pooled infection rate of mosquitoes. Aedes aegypti infection rates showed significant differences between the epidemic (10.68, 95% confidence interval [CI] = 7.04-15.62) and after epidemic periods of the study (6.15, 95% CI = 3.46-10.19). In addition, Ae. albopictus were also infected with dengue viruses. Increases in mosquito infection rates were associated with increases in human infection rates in the following trimester.

  3. Dengue in children.

    PubMed

    Verhagen, Lilly M; de Groot, Ronald

    2014-11-01

    Dengue is a mosquito-borne viral disease of expanding geographical range and increasing incidence. The vast majority of dengue cases are children less than 15 years of age. Dengue causes a spectrum of illness from mild fever to severe disease with plasma leakage and shock. Infants and children with secondary heterologous dengue infections are most at risk for severe dengue disease. Laboratory diagnosis of dengue can be established within five days of disease onset by direct detection of viral components in serum. After day five, serologic diagnosis provides indirect evidence of dengue. Currently, no effective antiviral agents are available to treat dengue infection. Therefore, treatment remains supportive, with emphasis on close hematological monitoring, recognition of warning signs of severe disease and fluid-replacement therapy and/or blood transfusions when required. Development of a dengue vaccine is considered a high public health priority. A safe and efficacious dengue vaccine would also be important for travelers. This review highlights the current understanding of dengue in children, including its clinical manifestations, pathogenesis, diagnostic tests, management and prevention. Copyright © 2014 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  4. Dengue in Java, Indonesia: Relevance of Mosquito Indices as Risk Predictors

    PubMed Central

    Wijayanti, Siwi P. M.; Sunaryo, Sunaryo; Suprihatin, Suprihatin; McFarlane, Melanie; Rainey, Stephanie M.; Dietrich, Isabelle; Schnettler, Esther; Biek, Roman; Kohl, Alain

    2016-01-01

    Background No vaccine is currently available for dengue virus (DENV), therefore control programmes usually focus on managing mosquito vector populations. Entomological surveys provide the most common means of characterising vector populations and predicting the risk of local dengue virus transmission. Despite Indonesia being a country strongly affected by DENV, only limited information is available on the local factors affecting DENV transmission and the suitability of available survey methods for assessing risk. Methodology/principal findings We conducted entomological surveys in the Banyumas Regency (Central Java) where dengue cases occur on an annual basis. Four villages were sampled during the dry and rainy seasons: two villages where dengue was endemic, one where dengue cases occurred sporadically and one which was dengue-free. In addition to data for conventional larvae indices, we collected data on pupae indices, and collected adult mosquitoes for species identification in order to determine mosquito species composition and population density. Traditionally used larval indices (House indices, Container indices and Breteau indices) were found to be inadequate as indicators for DENV transmission risk. In contrast, species composition of adult mosquitoes revealed that competent vector species were dominant in dengue endemic and sporadic villages. Conclusions/significance Our data suggested that the utility of traditional larvae indices, which continue to be used in many dengue endemic countries, should be re-evaluated locally. The results highlight the need for validation of risk indicators and control strategies across DENV affected areas here and perhaps elsewhere in SE Asia. PMID:26967524

  5. Dengue in Java, Indonesia: Relevance of Mosquito Indices as Risk Predictors.

    PubMed

    Wijayanti, Siwi P M; Sunaryo, Sunaryo; Suprihatin, Suprihatin; McFarlane, Melanie; Rainey, Stephanie M; Dietrich, Isabelle; Schnettler, Esther; Biek, Roman; Kohl, Alain

    2016-03-01

    No vaccine is currently available for dengue virus (DENV), therefore control programmes usually focus on managing mosquito vector populations. Entomological surveys provide the most common means of characterising vector populations and predicting the risk of local dengue virus transmission. Despite Indonesia being a country strongly affected by DENV, only limited information is available on the local factors affecting DENV transmission and the suitability of available survey methods for assessing risk. We conducted entomological surveys in the Banyumas Regency (Central Java) where dengue cases occur on an annual basis. Four villages were sampled during the dry and rainy seasons: two villages where dengue was endemic, one where dengue cases occurred sporadically and one which was dengue-free. In addition to data for conventional larvae indices, we collected data on pupae indices, and collected adult mosquitoes for species identification in order to determine mosquito species composition and population density. Traditionally used larval indices (House indices, Container indices and Breteau indices) were found to be inadequate as indicators for DENV transmission risk. In contrast, species composition of adult mosquitoes revealed that competent vector species were dominant in dengue endemic and sporadic villages. Our data suggested that the utility of traditional larvae indices, which continue to be used in many dengue endemic countries, should be re-evaluated locally. The results highlight the need for validation of risk indicators and control strategies across DENV affected areas here and perhaps elsewhere in SE Asia.

  6. Dengue infections in travellers

    PubMed Central

    Wilder-Smith, Annelies

    2012-01-01

    Dengue has been designated a major international public health problem by the World Health Organization (WHO). It is endemic in most tropical and sub-tropical countries, which are also popular tourist destinations. Travellers are not only at significant risk of acquiring dengue but they also contribute to its spread to non-endemic regions. Furthermore, they may serve as sentinels to alert the international community to epidemics in dengue-endemic regions. GeoSentinel, a global surveillance network, monitors all travel-related illnesses and estimates that dengue accounts for 2% of all illness in travellers returning from dengue-endemic regions. In fact, in travellers returning from South-east Asia, dengue is now a more frequent cause of febrile illness than malaria. Dengue-infected travellers returning home to countries where the vector exists can place the local population at risk of further spread of the disease with subsequent autochthonous cycles of infection. The true incidence of dengue amongst travellers may be underestimated because of variability in reporting requirements in different countries and under-diagnosis owing to the non-specific clinical presentation of the disease. Risk factors for acquiring dengue include duration of stay, season of travel and epidemic activity at the destination. Any pre-travel advice on the risks of developing dengue infections should consider these factors. PMID:22668447

  7. Dengue in India

    PubMed Central

    Gupta, Nivedita; Srivastava, Sakshi; Jain, Amita; Chaturvedi, Umesh C.

    2012-01-01

    Dengue virus belongs to family Flaviviridae, having four serotypes that spread by the bite of infected Aedes mosquitoes. It causes a wide spectrum of illness from mild asymptomatic illness to severe fatal dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS). Approximately 2.5 billion people live in dengue-risk regions with about 100 million new cases each year worldwide. The cumulative dengue diseases burden has attained an unprecedented proportion in recent times with sharp increase in the size of human population at risk. Dengue disease presents highly complex pathophysiological, economic and ecologic problems. In India, the first epidemic of clinical dengue-like illness was recorded in Madras (now Chennai) in 1780 and the first virologically proved epidemic of dengue fever (DF) occurred in Calcutta (now Kolkata) and Eastern Coast of India in 1963-1964. During the last 50 years a large number of physicians have treated and described dengue disease in India, but the scientific studies addressing various problems of dengue disease have been carried out at limited number of centres. Achievements of Indian scientists are considerable; however, a lot remain to be achieved for creating an impact. This paper briefly reviews the extent of work done by various groups of scientists in this country. PMID:23041731

  8. Dengue-associated kidney disease.

    PubMed

    Lizarraga, Karlo J; Nayer, Ali

    2014-01-01

    A mosquito-borne viral illness highly prevalent in the tropics and subtropics, dengue is considered a major global health threat by the World Health Organization. Directory of Open Access Journals (DOAJ), Google Scholar, PubMed (NLM), LISTA (EBSCO) and Web of Science have been searched. An RNA virus from the genus Flavivirus, dengue virus is transmitted by Aedes aegypti,the yellow fever mosquito. Dengue is asymptomatic in as many as one half of infected individuals. Dengue fever is an acute febrile illness accompanied by constitutional symptoms. Dengue hemorrhagic fever and dengue shock syndrome are the severe forms of dengue infection.Dengue infection has been associated with a variety of renal disorders. Acute renal failure is a potential complication of severe dengue infection and is typically associated with hypotension, rhabdomyolysis, or hemolysis. Acute renal failure complicates severe dengue infection in 2-5% of the cases and carries a high mortality rate. Proteinuria has been detected in as high as 74% of patients with severe dengue infection. Hematuria has been reported in up to 12.5% of patients. Various types of glomerulonephritis have been reported during or shortly after dengue infection in humans and mouse models of dengue infection. Mesangial proliferation and immune complex deposition are the dominant histologic features of dengue-associated glomerulonephritis. On a rare occasion, dengue infection is associated with systemic autoimmune disorders involving the kidneys. In the vast majority of cases, dengue infection and associated renal disorders are self-limited.

  9. Dengue virus vaccine development.

    PubMed

    Yauch, Lauren E; Shresta, Sujan

    2014-01-01

    Dengue virus (DENV) is a significant cause of morbidity and mortality in tropical and subtropical regions, causing hundreds of millions of infections each year. Infections range from asymptomatic to a self-limited febrile illness, dengue fever (DF), to the life-threatening dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). The expanding of the habitat of DENV-transmitting mosquitoes has resulted in dramatic increases in the number of cases over the past 50 years, and recent outbreaks have occurred in the United States. Developing a dengue vaccine is a global health priority. DENV vaccine development is challenging due to the existence of four serotypes of the virus (DENV1-4), which a vaccine must protect against. Additionally, the adaptive immune response to DENV may be both protective and pathogenic upon subsequent infection, and the precise features of protective versus pathogenic immune responses to DENV are unknown, complicating vaccine development. Numerous vaccine candidates, including live attenuated, inactivated, recombinant subunit, DNA, and viral vectored vaccines, are in various stages of clinical development, from preclinical to phase 3. This review will discuss the adaptive immune response to DENV, dengue vaccine challenges, animal models used to test dengue vaccine candidates, and historical and current dengue vaccine approaches.

  10. Biochemical evidence of efficacy of potash alum for the control of dengue vector Aedes aegypti (Linnaeus).

    PubMed

    Preet, Shabad; Sneha, A

    2011-06-01

    Aedes aegypti is the primary vector of dengue, yellow fever and chikungunya in India and other South East Asian countries, and novel insecticides for vector control are urgently needed. In the present investigation, efficacy of potash alum, a traditionally known double salt in Indian and Chinese medicine system, was tested against the larvae of dengue vector, A. aegypti. LC(50,) LC(90) and LC(99) values were recorded for various instar larvae where I instar larvae were found to be the most susceptible and IV instar larvae as the least susceptible one. The LC(50) values of crude and standard potash alum of various instar larvae ranged between 15.29 and 48.53 ppm and 20.50-65.10 ppm, respectively. Biochemical changes were also evidenced in IV instar A. aegypti larvae following a sublethal exposure for 24 h in the levels of various nutrient reserves and primary metabolites such as sugar, glycogen, lipids and proteins suggesting possible mode of action responsible for larval mortality. Sugar and glycogen concentrations were measured as 24.6 and 10.67 μg per five larvae in controls which were significantly (p<0.05) reduced by 32.11-93.98% and 39.26-94.47%, respectively, in larvae treated with crude alum. In controls, protein and lipid content were recorded as 210.74 and 94.71 μg per five larvae which dropped up to 26.53% and 25.5%, respectively, in larvae following treatment with crude alum. Moreover, drastic changes were also recorded for DNA content with 25.39-44.17% decrease in crude alum-treated larvae. It is evident from these results that potash alum, a fairly cheaper and readily available ecofriendly compound could be recommended as a potential chemical larvicide against dengue vector at mosquito breeding sites in the vicinity of human dwellings.

  11. Evaluation of the present dengue situation and control strategies against Aedes aegypti in Cebu City, Philippines.

    PubMed

    Mahilum, Milagros M; Ludwig, Mario; Madon, Minoo B; Becker, Norbert

    2005-12-01

    The present dengue situation and methods to control Aedes aegypti larvae in Cebu City, Philippines, were evaluated for the development of an integrated community-based dengue control program. The study included the detection of dengue infection among Filipino patients, surveying mosquito breeding sites to determine larval population density of Aedes aegypti, an evaluation of public knowledge, attitude, and personal protection practices against dengue, and an evaluation of the efficacy of VectoBac DT/Culinex Tab tablets based on Bacillus thuringiensis israelensis against Ae. aegypti larvae. Of the 173 human sera samples that were assayed for dengue viruses, 94.9% were positive, 2.2% negative and 2.8% equivocal. Thirty households were randomly chosen per Barangay "Villages" (lowest level of formal local administration). Of the 489 breeding sites surveyed, 29.4% were infested with Ae. aegypti larvae, with discarded tires having the highest infestation rate (69.4%). A survey of people's knowledge, attitude, and practices for integrated community-based dengue control showed that 68.7% of the interviewees were aware that dengue is transmitted by mosquitoes, but only 4.3% knew that a virus was the cause of the disease. The efficacy of one and two tablets of VectoBac DT/Culinex Tab, based on Bacillus thuringiensis israelensis, was assessed against the larvae of Ae. aegypti exposed to sunshine and shaded water containers in semi-field and field tests. In semi-field tests, 100% mortality was achieved until the 18th and 30th day after the application of one and two tablets, respectively, in sun-exposed containers. In shaded containers, 100% mortality was observed until the 30th and 36th day after the application of one and two tablets, respectively. In field tests, the tablets were effective for approximately 3 weeks.

  12. Mosquitoes infected with dengue viruses in Brazil

    PubMed Central

    2010-01-01

    Dengue epidemics have been reported in Brazil since 1985. The scenery has worsened in the last decade because several serotypes are circulating and producing a hyper-endemic situation, with an increase of DHF/DSS cases as well as the number of fatalities. Herein, we report dengue virus surveillance in mosquitoes using a Flavivirus genus-specific RT-Hemi-Nested-PCR assay. The mosquitoes (Culicidae, n = 1700) collected in the Northeast, Southeast and South of Brazil, between 1999 and 2005, were grouped into 154 pools. Putative genomes of DENV-1, -2 and -3 were detected in 6 mosquito pools (3.8%). One amplicon of putative DENV-1 was detected in a pool of Haemagogus leucocelaenus suggesting that this virus could be involved in a sylvatic cycle. DENV-3 was found infecting 3 pools of larvae of Aedes albopictus and the nucleotide sequence of one of these viruses was identified as DENV-3 of genotype III, phylogenetically related to other DENV-3 isolated in Brazil. This is the first report of a nucleotide sequence of DENV-3 from larvae of Aedes albopictus. PMID:20624314

  13. Mosquitoes, models, and dengue.

    PubMed

    Lifson, A R

    1996-05-04

    In the last 10 years dengue has spread markedly through Latin America and the Caribbean (Dominican Republic, Jamaica, Barbados, Mexico, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, Ecuador, Colombia, Venezuela, and Brazil). The mosquito Aedes aegypti has taken advantage of increased urbanization and crowding to transmit the dengue virus. The mosquito infests tires, cans, and water jars near dwellings. The female mosquito practices multiple, interrupted feeding. Thus, mosquito infesting and feeding practices facilitate dengue transmission in crowded conditions. Factors contributing to the spread of dengue include numbers of infected and susceptible human hosts, strain of dengue virus, size of mosquito population, feeding habits, time from infection to ability to transmit virus for both vector and host, likelihood of virus transmission from human to mosquito to human, and temperature (which affects vector distribution, size, feeding habits, and extrinsic incubation period). Public health models may use simulation models to help them plan or evaluate the potential impact of different intervention strategies and/or of environmental changes (e.g., global warming). Other factors contributing to the dengue epidemic are international travel, urbanization, population growth, crowding, poverty, a weakened public health infrastructure, and limited support for sustained disease control programs. Molecular epidemiology by nucleic acid sequence analysis is another sophisticated technique used to study infectious diseases. It showed that dengue type 3 isolated from Panama and Nicaragua in 1994 was identical to that responsible for the major dengue hemorrhagic fever epidemics in Sri Lanka and India in the 1980s. Public health officials must remember three priorities relevant to dengue and other emerging infections: the need to strengthen surveillance efforts, dedicated and sustained involvement in prevention and control needs at the local level, and a strong

  14. Dengue: a continuing global threat

    PubMed Central

    Guzman, Maria G.; Halstead, Scott B.; Artsob, Harvey; Buchy, Philippe; Farrar, Jeremy; Gubler, Duane J.; Hunsperger, Elizabeth; Kroeger, Axel; Margolis, Harold S.; Martínez, Eric; Nathan, Michael B.; Pelegrino, Jose Luis; Simmons, Cameron; Yoksan, Sutee; Peeling, Rosanna W.

    2014-01-01

    Dengue fever and dengue haemorrhagic fever are important arthropod-borne viral diseases. Each year, there are ~50 million dengue infections and ~500,000 individuals are hospitalized with dengue haemorrhagic fever, mainly in Southeast Asia, the Pacific and the Americas. Illness is produced by any of the four dengue virus serotypes. A global strategy aimed at increasing the capacity for surveillance and outbreak response, changing behaviours and reducing the disease burden using integrated vector management in conjunction with early and accurate diagnosis has been advocated. Antiviral drugs and vaccines that are currently under development could also make an important contribution to dengue control in the future. PMID:21079655

  15. Rhombencephalitis associated with Dengue fever.

    PubMed

    Verma, Rajesh; Bharti, Kavita; Mehta, Mannan; Bansod, Amrit

    2016-05-01

    Dengue infection is gradually disseminating throughout the world in alarming proportions. It is a arbovirus infection,transmitted by aedes mosquitoes. It is a multi-systemic disorder associated with varied neurological complications. There is increased trend of development of neurological complications in dengue fever. The neurological complications arising due to dengue infection can be categorized into central and neuromuscular complications. The central nervous system disorders reported with dengue fever are encephalopathy,encephalitis and myelitis.Here we report a case of rhombencephalitis associated with dengue fever. The literature does not mention rhombencephalitis occurring with dengue illness. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Dengue shock syndrome

    PubMed Central

    Sudulagunta, Sreenivasa Rao; Sodalagunta, Mahesh Babu; Sepehrar, Mona; Bangalore Raja, Shiva Kumar; Nataraju, Aravinda Settikere; Kumbhat, Mounica; Sathyanarayana, Deepak; Gummadi, Siddharth; Burra, Hemanth Kumar

    2016-01-01

    Dengue fever is a mosquito-borne arthropod-borne viral (arboviral) tropical disease in humans affecting 50–528 million people worldwide. The acute abdominal complications of dengue fever are acute appendicitis, acute pancreatitis, acute acalculous cholecystitis and non-specific peritonitis. Acute pancreatitis with new onset diabetes in dengue shock syndrome (DSS) is very rarely reported. We describe a case of 30-year-old man admitted in intensive care unit and was diagnosed with DSS with RT-PCR, NS1 antigen and dengue IgM antibody being positive. Abdominal ultrasound and computerized tomography confirmed acute pancreatitis. Patient required insulin after recovery. Diabetes mellitus caused by DSS is under-reported and lack of awareness may increase mortality and morbidity. PMID:28031845

  17. Controversies in dengue pathogenesis

    PubMed Central

    Halstead, Scott B

    2012-01-01

    Research into the pathogenesis of dengue fever has exploded over the last half-century, with issues that were considered simple becoming more complex as additional data are found. This has led to the development of a number of controversies that are being studied across the globe and debated in the literature. In this paper, the following six controversies are analysed and, where possible, resolved: the 1997 World Health Organization (WHO) case definition of dengue haemorrhagic fever (DHF) is not useful; DHF is not significantly associated with secondary dengue infection; DHF results from infection with a ‘virulent’ dengue virus; DHF is owing to abnormal T-cell responses; DHF results from auto-immune responses; and DHF results from direct infection of endothelial cells. PMID:22668442

  18. Dengue hemorrhagic fever

    MedlinePlus

    ... a severe, potentially deadly infection spread by some mosquitos. Causes Four different dengue viruses are known to ... occurs when a person is bitten by a mosquito that is infected with the virus. The mosquito ...

  19. [Urbanization and dengue ecology].

    PubMed

    Tauil, P L

    2001-01-01

    Demographic changes occurring in underdeveloped countries due to intense rural-urban migration since the 1960s have resulted in overcrowded cities with multiple deficiencies, particularly in housing and basic sanitation. Some 20% of the population in large and medium-sized cities live in slums or under similar conditions. Lack of regular water supply and public garbage collection foster the proliferation of potential breeding sites for Aedes aegypti (the main mosquito vector for dengue), including precarious reservoirs for potable water and disposable recipients which accumulate water, like used cans and plastic and glass bottles. Modern industries also produce large volumes of disposable materials. Propagation of the dengue virus and the spread of dengue vectors are favored by the high intensity, frequency, and speed of private and public transportation. Such factors can help explain the re-emergence of dengue, the most important arbovirus in the world today, affecting thousands of people each year.

  20. Influence of the mixtures composed of slow-release insecticide formulations against Aedes aegypti mosquito larvae reared in pond water.

    PubMed

    Alkenani, Naser A

    2017-09-01

    Vector borne diseases remain the major source of illness and death worldwide. Aedes aegypti is the primary carrier of dengue and dengue haemorrhagic fever in many developing countries in the tropical world. Because A. aegypti populations are becoming more and more resistant to conventional and non conventional insecticides, alternative strategies have to be rapidly implemented in the future for dengue vector control. The present study aimed to evaluate the larvicidal efficacy of slow-release formulations (SRFs) of bacterial insecticide Bactimos briquets blended with tow insect growth regulators (IGRs), Altosid XR - briquets and Dudim DT tablet respectively, against mosquito larvae of A. aegypti the primary vector of dengue fever in Jeddah governorate, Saudi Arabia. Semi-field trials were conducted at dengue mosquito research station, Dept. of Biological Sciences, faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia. The efficacy of the test formulations was calculated as the number of emerging adults compared to the initial number of larvae added or the inhibition of emergence (IE%). The assessment of effectiveness was made at weekly intervals until the level of efficacy decrease to ≤50% IE. The inhibition percentage of emergence of adult for each mixture weekly in addition to the calculation of the cycle of the effective centers for each mixture. Collectively, the results of the present investigation indicate that the combination of Bactimos with Altosid or Dudim maybe promising for controlling A. aegypti mosquito larvae provided that treatments persist at least during the whole dengue transmission season.

  1. Climate variation drives dengue dynamics

    PubMed Central

    Xu, Lei; Stige, Leif C.; Chan, Kung-Sik; Zhou, Jie; Yang, Jun; Sang, Shaowei; Wang, Ming; Yang, Zhicong; Yan, Ziqiang; Jiang, Tong; Lu, Liang; Yue, Yujuan; Liu, Xiaobo; Lin, Hualiang; Xu, Jianguo; Liu, Qiyong; Stenseth, Nils Chr.

    2017-01-01

    Dengue, a viral infection transmitted between people by mosquitoes, is one of the most rapidly spreading diseases in the world. Here, we report the analyses covering 11 y (2005–2015) from the city of Guangzhou in southern China. Using the first 8 y of data to develop an ecologically based model for the dengue system, we reliably predict the following 3 y of dengue dynamics—years with exceptionally extensive dengue outbreaks. We demonstrate that climate conditions, through the effects of rainfall and temperature on mosquito abundance and dengue transmission rate, play key roles in explaining the temporal dynamics of dengue incidence in the human population. Our study thus contributes to a better understanding of dengue dynamics and provides a predictive tool for preventive dengue reduction strategies. PMID:27940911

  2. Dengue-associated kidney disease

    PubMed Central

    J Lizarraga, Karlo; Nayer, Ali

    2014-01-01

    Context: A mosquito-borne viral illness highly prevalent in the tropics and subtropics, dengue is considered a major global health threat by the World Health Organization. Evidence Acquisitions: Directory of Open Access Journals (DOAJ), Google Scholar, PubMed (NLM), LISTA (EBSCO) and Web of Science have been searched. Results: An RNA virus from the genus Flavivirus, dengue virus is transmitted by Aedes aegypti,the yellow fever mosquito. Dengue is asymptomatic in as many as one half of infected individuals. Dengue fever is an acute febrile illness accompanied by constitutional symptoms. Dengue hemorrhagic fever and dengue shock syndrome are the severe forms of dengue infection.Dengue infection has been associated with a variety of renal disorders. Acute renal failure is a potential complication of severe dengue infection and is typically associated with hypotension, rhabdomyolysis, or hemolysis. Acute renal failure complicates severe dengue infection in 2-5% of the cases and carries a high mortality rate. Proteinuria has been detected in as high as 74% of patients with severe dengue infection. Hematuria has been reported in up to 12.5% of patients. Various types of glomerulonephritis have been reported during or shortly after dengue infection in humans and mouse models of dengue infection. Mesangial proliferation and immune complex deposition are the dominant histologic features of dengue-associated glomerulonephritis. On a rare occasion, dengue infection is associated with systemic autoimmune disorders involving the kidneys. Conclusions: In the vast majority of cases, dengue infection and associated renal disorders are self-limited. PMID:24772398

  3. Observations on Hospitalized Dengue Patients

    DTIC Science & Technology

    1987-01-01

    DENGUE PATIENTS IN MANILA Carman. R. Min oto* be" S. Siqpo Ommon D. Leus** Curds G. Ibyes* INTRODUCION to the Hospital of Infant Jesus between October...31, 1983 and March 31, 1984: Criteria for the diagnosis of dengue Dengue hemorrhagic fever (DHF) has been recognized infection were based on the...titer of later sample < 1:640. DHF epidemic.4𔃿 Since that time, there have only been a few- was differentiated from dengue fever (DF), and DHF was

  4. How dengue vector Aedes albopictus (Diptera: Culicidae) survive during the dry season in Dhaka City, Bangladesh?

    PubMed

    Chowdhury, Rajib; Chowdhury, Vashkar; Faria, Shyla; Huda, M Mamun; Laila, Runa; Dhar, Indrani; Maheswary, Narayan P; Dash, Aditya Prasad

    2014-09-01

    In 2000, a dengue outbreak occurred in Bangladesh that included Dhaka City. Both dengue vectors, Aedes aegypti and Ae. albopictus are present in Bangladesh. Aedes aegypti mosquitoes mainly breed in and around houses and Ae. albopictus is an outside breeder. There are many old trees throughout Dhaka City in different parks, streets and the university campus which may have holes that can contribute as potential breeding habitat for the dengue vector. Therefore, a survey was conducted to investigate the presence of eggs of the dengue vector mosquitoes in treeholes during the dry season in February 2001 to know their contribution on dengue outbreaks. All treeholes in 10 different localities (parks, streets and university campus) of Dhaka City were surveyed. All trees were examined for treeholes up to the height of approximately 3 m and sampled. Debris were collected and packed in poly bags and brought to the laboratory for detailed studies. These were then soaked with tap water to observe egg hatching. The soaked materials were kept up to 20 days covered by a fine mosquito net. After 2-3 days, the eggs started hatching and larvae were separated from the sample for rearing up to IV instar. A total of 245 treeholes were surveyed in 49 identified tree species and 18 unidentified trees. Altogether, 1365 Aedes larvae were found, of which 1096 were Aedes albopictus and 269 were other Aedes species. The largest number of larvae was observed in Delonix regia of Leguminosae family. The number of Aedes albopictus found in the treeholes have perfect positive correlation with the number of other Aedes species. Not a single egg of Aedes aegypti was found in this survey. This information will inform public health workers as well as the national control programme to help to solve mosquito borne diseases specially that of dengue. This is critical in planning for vector control operations due to the diversity of dengue outbreak in the nature.

  5. Dengue 3 Epidemic, Havana, 2001

    PubMed Central

    Peláez, Otto; Kourí, Gustavo; Pérez, Raúl; San Martín, José L.; Vázquez, Susana; Rosario, Delfina; Mora, Regla; Quintana, Ibrahim; Bisset, Juan; Cancio, Reynel; Masa, Ana M; Castro, Osvaldo; González, Daniel; Avila, Luis C.; Rodríguez, Rosmari; Alvarez, Mayling; Pelegrino, Jose L.; Bernardo, Lídice; Prado, Irina

    2004-01-01

    In June 2001, dengue transmission was detected in Havana, Cuba; 12,889 cases were reported. Dengue 3, the etiologic agent of the epidemic, caused the dengue hemorrhagic fever only in adults, with 78 cases and 3 deaths. After intensive vector control efforts, no new cases have been detected. PMID:15200868

  6. Insecticide susceptibility of the dengue vector, Aedes aegypti (L.) in Metropolitan Bangkok.

    PubMed

    Komalamisra, Narumon; Srisawat, Raweewan; Phanbhuwong, Theerawit; Oatwaree, Sompis

    2011-07-01

    Mosquito larvae were collected from the houses of dengue infected patients in Bangkok, Thailand from 55 sites (36 out of the 50 districts of Metropolitan Bangkok). Aedes aegypti larvae were tested against temephos using WHO bioassay techniques. Adult mosquitoes were tested for susceptibility to permethrin, deltamethrin, cyfluthrin, malathion and DDT using WHO diagnostic doses. Most of the larvae tested were susceptible to temephos. Only few specimens were resistant to temephos. Most adult mosquitoes were highly susceptible to malathion. Deltamethrin resistance was seen in 6 districts of Bangkok. Variable levels of susceptibility were seen with cyfluthrin. Most of the specimens showed resistance to permethrin and all specimens were resistant to DDT.

  7. Prevalence of dengue and diversity of cultivable bacteria in vector Aedes aegypti (L.) from two dengue endemic districts, Kanchanpur and Parsa of Nepal.

    PubMed

    Thapa, Srinivas; Pant, Narayan Dutt; Shrestha, Rojina; Gc, Ganga; Shrestha, Bidya; Pandey, Basu Dev; Gautam, Ishan

    2017-02-13

    Dengue fever, an endemic arboviral disease, represents one of the major public health concerns in Nepal. It is transmitted by bites of infected Aedes aegypti and Aedes albopictus, the former being primary vector. The bacterial community plays a significant role in biology of mosquitoes; however, the bacterial communities of primary vector A. aegypti remain unstudied in Nepal. The study was designed to determine the rate of dengue seropositivity and to explore the bacterial diversity of A. aegypti from dengue endemic districts, Kanchanpur and Parsa of Nepal. A cross-sectional study was conducted between June 2013 and November 2013 at two hospitals of Kanchanpur and Parsa. A total of 221 serum samples were collected from patients (inpatients and outpatients) suspected of suffering from dengue fever and attending Mahakali Zonal Hospital, Mahendranagar, Kanchanpur, and Narayani Zonal Hospital, Birgunj, Parsa. Detection of anti-dengue IgM was performed by using human dengue IgM capture ELISA. The larvae and pupae of mosquitoes (A. aegypti) were collected, reared, and emerged. Then, the bacteria were isolated and identified from the gut of identified mosquitoes by using standard methods. Out of total 221 serum samples collected from patients suspected of suffering from dengue fever, 34 (15.38%) were positive for anti-dengue IgM. Gram-negative bacteria were isolated in largest proportion (63%) followed by gram-positive cocci (23.27%) and gram-positive rods (13.73%). The most common cultivable bacteria isolated were Staphylococcus spp., Pseudomonas spp., and Acinetobacter spp. The average bacterial load in the vectors was 3.91 × 10(4) cfu/ml. High rate of anti-dengue IgM seropositivity was reported in our study. The environmental bacteria were predominantly isolated and identified in A. aegypti. The paratransgenic approach to control vector might be possible by spreading the genetically modified bacteria in larval habitat or shelter of adult mosquitoes.

  8. Preventing dengue through mobile phones: evidence from a field experiment in Peru.

    PubMed

    Dammert, Ana C; Galdo, Jose C; Galdo, Virgilio

    2014-05-01

    Dengue is the most rapidly spreading mosquito-borne viral disease in the world (WHO, 2009). During the last two decades, the dramatic rise in the number of dengue infections has been particularly evident in Latin American and the Caribbean countries. This paper examines the experimental evidence of the effectiveness of mobile phone technology in improving households' health preventive behavior in dengue-endemic areas. The main results suggest that repeated exposure to health information encourages households' uptake of preventive measures against dengue. As a result, the Breteau Index in treatment households, an objective measure of dengue risk transmission, is 0.10 standard deviations below the mean of the control group, which shows a reduction in the number of containers per household that test positive for dengue larvae. The estimates also show marginally significant effects of the intervention on self-reported dengue symptoms. Moreover, we use a multiple treatment framework that randomly assigns households to one of the four treatment groups in order to analyze the impacts of framing on health behavior. Different variants emphasized information on monetary and non-monetary benefits and costs. The main results show no statistical differences among treatment groups. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Incomplete surveillance of a dengue-2 epidemic in Ibagué, Colombia, 1995-1997.

    PubMed

    Camacho, Tania; de la Hoz, Fernando; Cárdenas, Victor; Sánchez, Carmen; de Calderón, Laura; Pérez, Ligia; Bermúdez, Antonio

    2004-06-01

    From April 1995 through November 1997 a dengue epidemic occurred in Ibagué (400,000 population), Colombia, where 3,419 cases were reported and DEN 2 virus was isolated from seven patients. A sero-survey conducted in 1996 found evidence of previous dengue infection in 9.6% of the population, indicating that many infections had not been reported. The dengue infections occurred in all age groups, but children under five years of age were most frequently infected. Forty-five percent of this Ibagué population were born after the re-appearance of dengue in Colombia in 1972, but have never been infected with dengue virus. Most of the cases reported as dengue hemorrhagic fever did not fulfill the current case definition. Aedes aegypti larvae were found in 19% of dwellings surveyed, most often in uncovered low tanks used for water storage. Many residents were not acquainted with the domestic nature of the mosquito vector. Health workers attributed the failure of the dengue control programs to lack of leadership and other administrative problems.

  10. Challenges encountered using standard vector control measures for dengue in Boa Vista, Brazil.

    PubMed

    Maciel-de-Freitas, Rafael; Valle, Denise

    2014-09-01

    In 2010, dengue virus (DENV) serotype-4 was detected during a dengue outbreak in the Amazonian city of Boa Vista. At that time Brazil was already endemic for DENV-1, DENV-2 and DENV-3. This was the first time DENV-4 was observed in the country after it was initially detected and eliminated in 1981. To hinder the spread of DENV-4 throughout Brazil, standard vector control measures were intensified. Vector control professionals visited 56 837 households in 22 out of 31 districts of Boa Vista, to eliminate mosquito-breeding sites. Water storage containers were treated with the larvicide diflubenzuron, and deltamethrin was sprayed for adult Aedes aegypti mosquitoes. Fifteen days later, a second larvae survey and additional deltamethrin applications were performed. In Brazil, dengue vector control is managed at all three government levels. Regular surveillance of Aedes aegypti is done four to six times a year to strengthen mosquito control activities in areas with high-vector density. Educational dengue control campaigns in communities are scarce, especially between outbreaks. In spite of extensive implementation of all standard control actions recommended by the Brazilian dengue control programme, only a slight decrease in mosquito density was detected. There is a need to redesign all levels of dengue control. Public consultation and engagement, behaviour change and actions that go beyond technical impositions are required. Vector control programme managers need to reflect on what constitutes good practices and whether intermittent information campaigns are effective measures for dengue prevention and control.

  11. [Nitric oxide in dengue pathology].

    PubMed

    Rodriguez-Ortega, M

    1998-01-01

    Nitric oxide (NO) is a multifunctional molecule that is involved in citotoxic as well as citoprotective processes, it's synthesis is highly regulated by the cell because an alteration in NO production is associated with a variety of pathologies, such as Septic, Anaphylactic and Hemorrhagic Shock. The clinical feature of dengue virus infection has a spectrum that goes from mild, dengue fever, to a severe disease, dengue hemorrhagic fever/dengue shock. Here, some evidences are discussed that links NO with the pathology of the severe disease cause by dengue virus.

  12. Dengue virus-mosquito interactions.

    PubMed

    Halstead, Scott B

    2008-01-01

    The mosquito Aedes aegypti is more widely dispersed now than at any time in the past, placing billions of humans at risk of infection with one or more of the four dengue viruses. This review presents and discusses information on mosquito-dengue infection dynamics and describes the prominent role that temperature and rainfall play in controlling dengue viral transmission including discussions of the effect of interannual climate variations and the predicted effect of global warming. Complementary human determinants of dengue epidemiology include viremia titer, variation in viremic period, enhanced viremias, and threshold viremia. Topics covered include epidemiological phenomena such as traveling waves, the generation of genetic diversity of dengue viruses following virgin soil introductions and in hyperendemic settings, and evidence for and against viral virulence as a determinant of the severity of dengue infections. Also described is the crucial role of monotypic and heterotypic herd immunity in shaping dengue epidemic behavior.

  13. Dengue Virus Infection in Africa

    PubMed Central

    Kuritsky, Joel N.; Letson, G. William; Margolis, Harold S.

    2011-01-01

    Reported incidence of dengue has increased worldwide in recent decades, but little is known about its incidence in Africa. During 1960–2010, a total of 22 countries in Africa reported sporadic cases or outbreaks of dengue; 12 other countries in Africa reported dengue only in travelers. The presence of disease and high prevalence of antibody to dengue virus in limited serologic surveys suggest endemic dengue virus infection in all or many parts of Africa. Dengue is likely underrecognized and underreported in Africa because of low awareness by health care providers, other prevalent febrile illnesses, and lack of diagnostic testing and systematic surveillance. Other hypotheses to explain low reported numbers of cases include cross-protection from other endemic flavivirus infections, genetic host factors protecting against infection or disease, and low vector competence and transmission efficiency. Population-based studies of febrile illness are needed to determine the epidemiology and true incidence of dengue in Africa. PMID:21801609

  14. Progress towards a dengue vaccine.

    PubMed

    Webster, Daniel P; Farrar, Jeremy; Rowland-Jones, Sarah

    2009-11-01

    The spread of dengue virus throughout the tropics represents a major, rapidly growing public health problem with an estimated 2.5 billion people at risk of dengue fever and the life-threatening disease, severe dengue. A safe and effective vaccine for dengue is urgently needed. The pathogenesis of severe dengue results from a complex interaction between the virus, the host, and, at least in part, immune-mediated mechanisms. Vaccine development has been slowed by fears that immunisation might predispose individuals to the severe form of dengue infection. A pipeline of candidate vaccines now exists, including live attenuated, inactivated, chimeric, DNA, and viral-vector vaccines, some of which are at the stage of clinical testing. In this Review, we present what is understood about dengue pathogenesis and its implications for vaccine design, the progress that is being made in the development of a vaccine, and the future challenges.

  15. Scientists try new strategy to eradicate dengue fever.

    PubMed

    Kenyon, G

    1999-02-27

    In a bid to reduce the risk of dengue fever in parts of Vietnam, the Australian Foundation for the Peoples of Asia and the Pacific, an aid organization, recently completed a 3-year program using the mesocyclops crustacean, an organism about 1 mm long which eats the larvae of mosquitos which transmit dengue fever. The program appears to eradicated the larvae from the northern Vietnamese province of Phan Boi, and there was a 75% success rate in other provinces. The Queensland Institute of Medical Research and the Vietnam National Institute of Hygiene and Epidemiology were the organizations involved in coordinating drops of the organism into mosquito breeding areas such as wells, water tanks, and household water containers. A community education and clean-up program was also implemented to teach residents about the importance of throwing away unused buckets and other containers which could hold stagnant water and become potential breeding grounds for disease. It is important to prevent dengue because existing treatments are inadequate.

  16. Quasispecies of dengue virus.

    PubMed

    Kurosu, Takeshi

    2011-12-01

    Pathogenic viruses have RNA genomes that cause acute and chronic infections. These viruses replicate with high mutation rates and exhibit significant genetic diversity, so-called viral quasispecies. Viral quasispecies play an important role in chronic infectious diseases, but little is known about their involvement in acute infectious diseases such as dengue virus (DENV) infection. DENV, the most important human arbovirus, is a causative agent of dengue fever (DF) and dengue hemorrhagic fever (DHF). Accumulating observations suggest that DENV exists as an extremely diverse virus population, but its biological significance is unclear. In other virus diseases, quasispecies affect the therapeutic strategies using drugs and vaccines. Here, I describe the quasispecies of DENV and discuss the possible role of quasispecies in the pathogenesis of and therapeutic strategy against DENV infection in comparison with other viruses such as Hepatitis C virus, human immunodeficiency virus type 1, and poliovirus.

  17. Micronutrients and dengue.

    PubMed

    Ahmed, Sundus; Finkelstein, Julia L; Stewart, Anna M; Kenneth, John; Polhemus, Mark E; Endy, Timothy P; Cardenas, Washington; Mehta, Saurabh

    2014-11-01

    Dengue virus infection is the most widespread mosquito-borne viral infection in humans and has emerged as a serious global health challenge. In the absence of effective treatment and vaccine, host factors including nutritional status, which may alter disease progression, need investigation. The interplay between nutrition and other infections is well-established, and modulation of nutritional status often presents a simple low-cost method of interrupting transmission, reducing susceptibility, and/or ameliorating disease severity. This review examines the evidence on the role of micronutrients in dengue virus infection. We found critical issues and often inconsistent results across studies; this finding along with the lack of sufficient literature in this field have limited our ability to make any recommendations. However, vitamins D and E have shown promise in small supplementation trials. In summary, the role of micronutrients in dengue virus infection is an exciting research area and needs to be examined in well-designed studies with larger samples.

  18. Working with dauer larvae.

    PubMed

    Karp, Xantha

    2016-07-14

    Dauer diapause is a stress-resistant, developmentally quiescent, and long-lived larval stage adopted by Caenorhabditis elegans when conditions are unfavorable for growth and reproduction. This chapter contains methods to induce dauer larva formation, to isolate dauer larvae, and to study pre- and post-dauer stages.

  19. Protect Yourself and Your Baby from Dengue

    MedlinePlus

    Protect Yourself and Your Baby from Dengue Avoid mosquito bites during pregnancy to prevent dengue in your ... To prevent dengue virus infection during pregnancy » Use mosquito repellents with up to 50% DEET, picaridin, IR3535 ...

  20. Oviposition Site Selection by the Dengue Vector Aedes aegypti and Its Implications for Dengue Control

    PubMed Central

    Wong, Jacklyn; Stoddard, Steven T.; Astete, Helvio; Morrison, Amy C.; Scott, Thomas W.

    2011-01-01

    Background Because no dengue vaccine or antiviral therapy is commercially available, controlling the primary mosquito vector, Aedes aegypti, is currently the only means to prevent dengue outbreaks. Traditional models of Ae. aegypti assume that population dynamics are regulated by density-dependent larval competition for food and little affected by oviposition behavior. Due to direct impacts on offspring survival and development, however, mosquito choice in oviposition site can have important consequences for population regulation that should be taken into account when designing vector control programs. Methodology/Principal Findings We examined oviposition patterns by Ae. aegypti among 591 naturally occurring containers and a set of experimental containers in Iquitos, Peru. Using larval starvation bioassays as an indirect measure of container food content, we assessed whether females select containers with the most food for their offspring. Our data indicate that choice of egg-laying site is influenced by conspecific larvae and pupae, container fill method, container size, lid, and sun exposure. Although larval food positively influenced oviposition, our results did not support the hypothesis that females act primarily to maximize food for larvae. Females were most strongly attracted to sites containing immature conspecifics, even when potential competitors for their progeny were present in abundance. Conclusion/Significance Due to strong conspecific attraction, egg-laying behavior may contribute more to regulating Ae. aegypti populations than previously thought. If highly infested containers are targeted for removal or larvicide application, females that would have preferentially oviposited in those sites may instead distribute their eggs among other suitable, previously unoccupied containers. Strategies that kill mosquitoes late in their development (i.e., insect growth regulators that kill pupae rather than larvae) will enhance vector control by creating

  1. A Dengue Vaccine.

    PubMed

    Durbin, Anna P

    2016-06-30

    Denvaxia is the first licensed vaccine for the prevention of dengue. It is a live vaccine developed using recombinant DNA technology. The vaccine is given as three doses over the course of a year and has the potential to prevent hundreds of thousands of hospitalizations each year.

  2. Dengue in Florida (USA)

    PubMed Central

    Rey, Jorge R.

    2014-01-01

    Florida (USA), particularly the southern portion of the State, is in a precarious situation concerning arboviral diseases. The geographic location, climate, lifestyle, and the volume of travel and commerce are all conducive to arbovirus transmission. During the last decades, imported dengue cases have been regularly recorded in Florida, and the recent re-emergence of dengue as a major public health concern in the Americas has been accompanied by a steady increase in the number of imported cases. In 2009, there were 28 cases of locally transmitted dengue in Key West, and in 2010, 65 cases were reported. Local transmission was also reported in Martin County in 2013 (29 cases), and isolated locally transmitted cases were also reported from other counties in the last five years. Dengue control and prevention in the future will require close cooperation between mosquito control and public health agencies, citizens, community and government agencies, and medical professionals to reduce populations of the vectors and to condition citizens and visitors to take personal protection measures that minimize bites by infected mosquitoes. PMID:26462955

  3. [Dengue, Zika and Chikungunya].

    PubMed

    Kantor, Isabel N

    2016-01-01

    Arboviruses are transmitted by arthropods, including those responsible for the current pandemic: alphavirus (Chikungunya) and flaviviruses (dengue and Zika). Its importance increased in the Americas over the past 20 years. The main vectors are Aedes aegypti and A. albopictus. Dengue infection provides long lasting immunity against the specific serotype and temporary to the other three. Subsequent infection by another serotype determines more serious disease. There is a registered vaccine for dengue, Dengvaxia (Sanofi Pasteur). Other two (Butantan and Takeda) are in Phase III in 2016. Zika infection is usually asymptomatic or occurs with rash, conjunctivitis and not very high fever. There is no vaccine or specific treatment. It can be transmitted by parental, sexual and via blood transfusion. It has been associated with microcephaly. Chikungunya causes prolonged joint pain and persistent immune response. Two candidate vaccines are in Phase II. Dengue direct diagnosis is performed by virus isolation, RT-PCR and ELISA for NS1 antigen detection; indirect methods are ELISA-IgM (cross-reacting with other flavivirus), MAC-ELISA, and plaque neutralization. Zika is diagnosed by RT-PCR and virus isolation. Serological diagnosis cross-reacts with other flavivirus. For CHIKV culture, RT-PCR, MAC-ELISA and plaque neutralization are used. Against Aedes organophosphate larvicides (temephos), organophosphorus insecticides (malathion and fenitrothion) and pyrethroids (permethrin and deltamethrin) are usually employed. Resistance has been described to all these products. Vegetable derivatives are less expensive and biodegradable, including citronella oil, which microencapsulated can be preserved from evaporation.

  4. Human Immune Response to Dengue Infections

    DTIC Science & Technology

    1990-07-31

    soluble CD4 (sCD4), soluble CD8 (sCD8) interleukin-2 (IL-2) and interferon gamma (IFNy), in the sera of patients with DHF/DSS and dengue Fever (DF...soluble IL-2 receptor (sIL-2R) in the acute sera of patients with dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS) and with dengue fever (DF...21 4 I. INTRODUCTION Dengue virus infection induces two types of symptoms; dengue fever (DF) and dengue hemorrhagic fever (DHF)/dengue

  5. Outlook for a dengue vaccine.

    PubMed

    Norrby, R

    2014-05-01

    Dengue is an increasing medical problem in subtropical and tropical countries. The search for a safe and effective vaccine is complicated by the fact that there are four types of dengue virus and that, if a vaccine is live attenuated, it should be proven not to cause the life-threatening form of dengue, dengue haemorrhagic fever. So far one vaccine candidate, a four-valent chimeric vaccine constructed from a yellow fever vaccine strain, has reached large clinical trials and has been shown to offer protection against dengue types 1, 3 and 54 but not against dengue type 2. It is highly likely that an effective vaccine will be available in the next decade.

  6. Clustering, climate and dengue transmission.

    PubMed

    Junxiong, Pang; Yee-Sin, Leo

    2015-06-01

    Dengue is currently the most rapidly spreading vector-borne disease, with an increasing burden over recent decades. Currently, neither a licensed vaccine nor an effective anti-viral therapy is available, and treatment largely remains supportive. Current vector control strategies to prevent and reduce dengue transmission are neither efficient nor sustainable as long-term interventions. Increased globalization and climate change have been reported to influence dengue transmission. In this article, we reviewed the non-climatic and climatic risk factors which facilitate dengue transmission. Sustainable and effective interventions to reduce the increasing threat from dengue would require the integration of these risk factors into current and future prevention strategies, including dengue vaccination, as well as the continuous support and commitment from the political and environmental stakeholders.

  7. Dengue in a changing climate.

    PubMed

    Ebi, Kristie L; Nealon, Joshua

    2016-11-01

    Dengue is the world's most important arboviral disease in terms of number of people affected. Over the past 50 years, incidence increased 30-fold: there were approximately 390 million infections in 2010. Globalization, trade, travel, demographic trends, and warming temperatures are associated with the recent spread of the primary vectors Aedes aegypti and Aedes albopictus and of dengue. Overall, models project that new geographic areas along the fringe of current geographic ranges for Aedes will become environmentally suitable for the mosquito's lifecycle, and for dengue transmission. Many endemic countries where dengue is likely to spread further have underdeveloped health systems, increasing the substantial challenges of disease prevention and control. Control focuses on management of Aedes, although these efforts have typically had limited effectiveness in preventing outbreaks. New prevention and control efforts are needed to counter the potential consequences of climate change on the geographic range and incidence of dengue, including novel methods of vector control and dengue vaccines.

  8. Trends of Dengue Disease Epidemiology

    PubMed Central

    Cucunawangsih; Lugito, Nata Pratama Hardjo

    2017-01-01

    Dengue disease is an emerging mosquito-borne viral infection transmitted between humans by Aedes spp. that are distributed mainly in the tropical and subtropical region along with chikungunya and zika diseases. The distribution of dengue disease is influenced by local variation, such as geography, rainfall, temperature, and rapid urbanization or migration. The epidemy of mosquito-borne infection significantly led to increased number of cases and hyperendemicity which induce a more severe form of dengue accompanied by cocirculation of chikungunya and zika. The rapid global spreading of dengue disease created public health burdens that are presently unfulfilled by the absence of specific therapy, simple diagnosis tool for the early phase, and effective and efficient vector control system. This review highlights the current situation of dengue distribution, epidemiology, and new strategies for early dengue diagnosis and risk prediction of severity that can be used to improve oversight and alleviate the heavy burden of the disease. PMID:28579763

  9. Fighting arboviral diseases: low toxicity on mammalian cells, dengue growth inhibition (in vitro), and mosquitocidal activity of Centroceras clavulatum-synthesized silver nanoparticles.

    PubMed

    Murugan, Kadarkarai; Aruna, Palanimuthu; Panneerselvam, Chellasamy; Madhiyazhagan, Pari; Paulpandi, Manickam; Subramaniam, Jayapal; Rajaganesh, Rajapandian; Wei, Hui; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Syuhei, Ban; Canale, Angelo; Benelli, Giovanni

    2016-02-01

    Dengue is a mosquito-borne viral disease that has rapidly spread in all regions of the world in recent years. Female mosquitoes, mainly Aedes aegypti, transmit dengue. Approximately 3,900 million people, in 128 countries, are at risk of dengue infection. Recently, a focus has been provided on the potential of green-synthesized nanoparticles as inhibitors of the production of dengue viral envelope (E) protein in Vero cells and downregulators of the expression of dengue viral E gene. Algae are an outstanding reservoir of novel compounds, which may help in the fight against mosquito-borne diseases. In this research, silver nanoparticles (AgNP) were rapidly synthesized using a cheap extract of the alga Centroceras clavulatum. AgNP were characterized by UV–vis spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). In mosquitocidal assays, LC50 values of C. clavulatum extract against A. aegypti larvae and pupae were 269.361 ppm (larva I), 309.698 ppm (larva II), 348.325 ppm (larva III), 387.637 ppm (larva IV), and 446.262 ppm (pupa). C. clavulatum extract also exhibited moderate antioxidant activity, both in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) radical scavenging assays. LC50 values of C. clavulatum-synthesized AgNP were 21.460 ppm (larva I), 23.579 ppm (larva II), 25.912 ppm (larva III), 29.155 ppm (larva IV), and 33.877 ppm (pupa). Furthermore, C. clavulatum-synthesized AgNP inhibited dengue (serotype dengue virus type-2 (DEN-2)) viral replication in Vero cells. Notably, 50 μg/ml of green-synthesized AgNP showed no cytotoxicity on Vero cells while reduced DEN-2 viral growth of more than 80%; 12.5 μg/ml inhibited viral growth of more than 50%. Cellular internalization assays highlighted that untreated infected cells showed high intensity of fluorescence emission, which denotes high level of viral internalization. Conversely

  10. Cutaneous Larva Migrans

    MedlinePlus

    ... burrowing of larvae. People who are exposed to soil and sand are most likely to be infected. ... Truth 12/19/2013 Osteopathic Training Statement Online Surveys About AOCD The AOCD was recognized in 1958 ...

  11. Dengue Research Opportunities in the Americas

    PubMed Central

    Laughlin, Catherine A.; Morens, David M.; Cassetti, M. Cristina; Costero-Saint Denis, Adriana; San Martin, Jose-Luis; Whitehead, Stephen S.; Fauci, Anthony S.

    2012-01-01

    Dengue is a systemic arthropod-borne viral disease of major global public health importance. At least 2.5 billion people who live in areas of the world where dengue occurs are at risk of developing dengue fever (DF) and its severe complications, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Repeated reemergences of dengue in sudden explosive epidemics often cause public alarm and seriously stress healthcare systems. The control of dengue is further challenged by the lack of effective therapies, vaccines, and point-of-care diagnostics. Despite years of study, even its pathogenic mechanisms are poorly understood. This article discusses recent advances in dengue research and identifies challenging gaps in research on dengue clinical evaluation, diagnostics, epidemiology, immunology, therapeutics, vaccinology/clinical trials research, vector biology, and vector ecology. Although dengue is a major global tropical pathogen, epidemiologic and disease control considerations in this article emphasize dengue in the Americas. PMID:22782946

  12. Virulence Markers of Dengue Viruses

    DTIC Science & Technology

    1988-06-10

    AD VIRULENCE MARKERS OF DENGUE VIRUSES 00 ANNUAL REPORT 0 James L. Hardy and Srisakul C. Kliks June 10, 1988 Supported by U.S. ARMY MEDICAL RESEARCH...Virulence Markers of Dengue Viruses (U) 12. PERSONAL AUTHOR(S) James L. Hardy ind Sriqakul.C. Klik,,q 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF...TERMS (Continue on reverse it necessary and identify by block number) FIELD GROUP SUB-GROUP Dengue viruses, dengue hemorrhagic fever, virulence, U3

  13. Baylisascaris larva migrans.

    PubMed

    Kazacos, Kevin R; Jelicks, Linda A; Tanowitz, Herbert B

    2013-01-01

    Baylisascaris procyonis is a roundworm of the raccoon found primarily in North America but also known to occur in other parts of the world including South America, Europe, and Japan. Migration of the larvae of this parasite is recognized as a cause of clinical neural larva migrans (NLM) in humans, primarily children. It is manifested as meningoencephalitis associated with marked eosinophilia of the cerebrospinal fluid and peripheral blood. Diagnosis is made by recovering and identifying larvae in or from the tissues, epidemiological history, serology, and imaging of the central nervous system. Treatment is with albendazole and steroids, although the prognosis is generally poor. This parasite can also cause ocular larva migrans (OLM) which usually presents as diffuse unilateral subacute neuroretinitis (DUSN). The ocular diagnosis can be made by visualizing the larva in the eye and by serology. Intraocular larvae can be destroyed by photocoagulation although albendazole and steroids may also be used. However, once visual disturbance is established the prognosis for improved vision is poor. Related Baylisascaris species occur in skunks, badgers, and certain other carnivores, although most cases of NLM are caused by B. procyonis. Baylisascaris procyonis has also been found in kinkajous in the USA and South America and may also occur in related procyonids (coatis, olingos, etc.). Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Overview of current situation of dengue and dengue vector control

    USDA-ARS?s Scientific Manuscript database

    Dengue is the most important arbovirus of humans in the world. It is caused by one of four closely related virus serotypes whose primary vector is Aedes aegypti and secondarily by Ae. albopictus. A global dengue pandemic began in Southeast Asia after World War II and has intensified during the las...

  15. Dengue eye disease.

    PubMed

    Ng, Aaron W; Teoh, Stephen C

    2015-01-01

    Dengue fever, a viral disease epidemic in some parts of the world, is of considerable international concern, with a growing incidence owing to developing urbanization, tourism, and trade. Ocular manifestations of dengue fever are uncommon, but of great significance. Proposed mechanisms include direct viral infection as well as immunologic phenomena. Common manifestations include subconjunctival, vitreous, and retinal hemorrhages; posterior uveitis; optic neuritis; and maculopathies such as foveolitis, hemorrhage, and edema. Main symptoms include blurring of vision, scotomata, metamorphopsia, and floaters. Diagnostic and monitoring investigations described included optical coherence tomography, fundus fluorescein and indocyanine green angiography, visual field analysis, and electrophysiologic tests. Management is based on clinical presentation and includes active surveillance as well as various anti-inflammatory and immunosuppressive therapies. There have been no prospective, randomized therapeutic trials, and it is unclear if the disease is self-limiting or if treatment is actually beneficial. Prognosis varies, ranging from full resolution to permanent vision loss despite intervention.

  16. Wolbachia versus dengue

    PubMed Central

    Bull, James J.; Turelli, Michael

    2013-01-01

    A novel form of biological control is being applied to the dengue virus. The agent is the maternally transmitted bacterium Wolbachia, naturally absent from the main dengue vector, the mosquito Aedes aegypti. Three Wolbachia-based control strategies have been proposed. One is suppression of mosquito populations by large-scale releases of males incompatible with native females; this intervention requires ongoing releases. The other interventions transform wild mosquito populations with Wolbachia that spread via the frequency-dependent fitness advantage of Wolbachia-infected females; those interventions potentially require just a single, local release for area-wide disease control. One of these latter strategies uses Wolbachia that shortens mosquito life, indirectly preventing viral maturation/transmission. The other strategy uses Wolbachia that block viral transmission. All interventions can be undermined by viral, bacterial or mosquito evolution; viral virulence in humans may also evolve. We examine existing theory, experiments and comparative evidence to motivate predictions about evolutionary outcomes. (i) The life-shortening strategy seems the most likely to be thwarted by evolution. (ii) Mosquito suppression has a reasonable chance of working locally, at least in the short term, but long-term success over large areas is challenging. (iii) Dengue blocking faces strong selection for viral resistance but may well persist indefinitely at some level. Virulence evolution is not mathematically predictable, but comparative data provide no precedent for Wolbachia increasing dengue virulence. On balance, our analysis suggests that the considerable possible benefits of these technologies outweigh the known negatives, but the actual risk is largely unknown. PMID:24481199

  17. Micronutrients and Dengue

    PubMed Central

    Ahmed, Sundus; Finkelstein, Julia L.; Stewart, Anna M.; Kenneth, John; Polhemus, Mark E.; Endy, Timothy P.; Cardenas, Washington; Mehta, Saurabh

    2014-01-01

    Dengue virus infection is the most widespread mosquito-borne viral infection in humans and has emerged as a serious global health challenge. In the absence of effective treatment and vaccine, host factors including nutritional status, which may alter disease progression, need investigation. The interplay between nutrition and other infections is well-established, and modulation of nutritional status often presents a simple low-cost method of interrupting transmission, reducing susceptibility, and/or ameliorating disease severity. This review examines the evidence on the role of micronutrients in dengue virus infection. We found critical issues and often inconsistent results across studies; this finding along with the lack of sufficient literature in this field have limited our ability to make any recommendations. However, vitamins D and E have shown promise in small supplementation trials. In summary, the role of micronutrients in dengue virus infection is an exciting research area and needs to be examined in well-designed studies with larger samples. PMID:25200269

  18. Prospects for dengue vaccines for travelers

    PubMed Central

    2016-01-01

    Travel-acquired dengue cases have been increasing as the overall global dengue burden has expanded. In Korea, imported dengue cases have been reported since 2000 when it first became a notifiable disease. During the first four months of 2016, three times more dengue cases were reported in Korea than during the same period the previous year. A safe and efficacious vaccine for travelers would be beneficial to prevent dengue disease in individual travelers and potentially decrease the risk of virus spread to non-endemic areas. Here, we summarize the characteristics of dengue vaccines for travelers and review dengue vaccines currently licensed or in clinical development. PMID:27489798

  19. Baylisascaris Larva Migrans

    USGS Publications Warehouse

    Kazacos, Kevin R.; Abbott, Rachel C.; Van Riper, Charles

    2016-05-26

    SummaryBaylisascaris procyonis, the common raccoon roundworm, is the most commonly recognized cause of clinical larva migrans (LM) in animals, a condition in which an immature parasitic worm or larva migrates in a host animal’s tissues, causing obvious disease. Infection with B. procyonis is best known as a cause of fatal or severe neurologic disease that results when the larvae invade the brain, the spinal cord, or both; this condition is known as neural larva migrans (NLM). Baylisascariasis is a zoonotic disease, that is, one that is transmissible from animals to humans. In humans, B. procyonis can cause damaging visceral (VLM), ocular (OLM), and neural larva migrans. Due to the ubiquity of infected raccoons around humans, there is considerable human exposure and risk of infection with this parasite. The remarkable disease-producing capability of B. procyonis in animals and humans is one of the most significant aspects of the biology of ascarids (large roundworms) to come to light in recent years. Infection with B. procyonis has important health implications for a wide variety of free-ranging and captive wildlife, zoo animals, domestic animals, as well as human beings, on both an individual and population level. This report, eighth in the series of U.S. Geological Survey Circulars on zoonotic diseases, will help us to better understand the routes of Baylisascaris procyonis infections and how best to adequately monitor this zoonotic disease.

  20. Factors associated with dengue prevention and control in two villages in a central Thai province: a retrospective review.

    PubMed

    Thakolwiboon, Smathorn; Benjatikul, Nattorn; Sathianvichitr, Kanchalika; Prapathrangsee, Kawintra; Tienmontri, Taniya; Ratanaamonsakul, Wirote; Assantachai, Prasert; Homsanit, Mayuree

    2013-08-01

    To study the factors associated with dengue prevention and control in Moo 6 (the 6th village) and Moo 7 of Tambon Kaeng-phak-kut, Thaluang District, Lopburi Province. The authors reviewed the raw data collected by public health officers and village health volunteers (VHVs) as their routine tasks. The authors analyzed the data, 30 dwellings per each village, to compare the demographics, knowledge, attitude, and practice of subjects from Moo 6, a dengue-outbreak community, with that from Moo 7, a control group, as well as larval indices between these 2 studied groups. The present retrospective study is approved by Siriraj Institutional Review Board, Certificate of Approval No. Si393/2012. Both groups of subjects had no statistically significant difference in basic dengue knowledge (p = 0.862), attitude towards dengue prevention and control, practical knowledge (p = 0.457), and actual practice to eliminate Aedes larvae and prevent it laying eggs, except for the practice of managing water container in bathroom or toilet (p = 0.015). On the other hand, dengue incidence and larval indices of both villages were apparently different. Although incorrect basic dengue and practical knowledge of subjects from both villages were similar dengue outbreak in Moo 6 of Tambon Kaeng-phak-kut was superior. It may be due to difference in actual practice on larval elimination in water container in bathroom or toilet as well as other factors other than personal factors such as public services, public places, and community surroundings.

  1. Dengue antibodies in blood donors

    PubMed Central

    Ribas-Silva, Rejane Cristina; Eid, Andressa Ahmad

    2012-01-01

    Background Dengue is an urban arbovirus whose etiologic agent is a virus of the genus Flavorius with four distinct antigen serotypes (DENV-1, DENV-2, DENV-3 and DENV-4) that is transmitted to humans through the bite of the mosquito Aedes aegypti. The Campo Mourão region in Brazil is endemic for dengue fever. Obtective The aim of this study was to evaluate the presence of IgG and IgM antibodies specific to the four serotypes of dengue in donors of the blood donor service in the city of Campo Mourão. Methods Epidemiological records were evaluated and 4 mL of peripheral blood from 213 blood donors were collected in tubes without anticoagulant. Serum was then obtained and immunochromatographic tests were undertaken (Imuno-Rápido Dengue IgM/IgGTM). Individuals involved in the study answered a social and epidemiological questionnaire on data which included age, gender and diagnosis of dengue. Results Only three (1.4%) of the 213 blood tests were positive for IgG anti-dengue antibodies. No donors with IgM antibody, which identifies acute infection, were identified. Conclusions The results of the current analysis show that the introduction of quantitative or molecular serological methods to determine the presence of anti-dengue antibodies or the detection of the dengue virus in blood donors in endemic regions should be established so that the quality of blood transfusions is guaranteed. PMID:23049418

  2. Reemergence of dengue in Mauritius.

    PubMed

    Issack, Mohammad I; Pursem, Vidula N; Barkham, Timothy M S; Ng, Lee Ching; Inoue, Masafumi; Manraj, Shyam S

    2010-04-01

    Dengue reemerged in Mauritius in 2009 after an absence of >30 years, and >200 cases were confirmed serologically. Molecular studies showed that the outbreak was caused by dengue virus type 2. Phylogenetic analysis of the envelope gene identified 2 clades of the virus. No case of hemorrhagic fever was recorded.

  3. Dengue-1 virus isolation during first dengue fever outbreak on Easter Island, Chile.

    PubMed

    Perret, Cecilia; Abarca, Katia; Ovalle, Jimena; Ferrer, Pablo; Godoy, Paula; Olea, Andrea; Aguilera, Ximena; Ferrés, Marcela

    2003-11-01

    Dengue virus was detected for the first time in Chile, in an outbreak of dengue fever on Easter Island. The virus was isolated in tissue culture and characterized by reverse transcription-polymerase chain reaction as being dengue type 1.

  4. Odonate Nymphs: Generalist Predators and Their Potential in the Management of Dengue Mosquito, Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    Akram, Waseem; Ali-Khan, Hafiz Azhar

    2016-01-01

    Background: Dengue is amongst the most serious mosquito-borne infectious disease with hot spots in tropical and subtropical parts of the world. Unfortunately, no licensed vaccine for the disease is currently available in medicine markets. The only option available is the management of dengue vector mosquito, Aedes aegypti (Diptera: Culicidae). Method: Predatory potential of five odonate nymphs namely Anax parthenope, Bradinopyga geminate, Ischnura forcipata, Rhinocypha quadrimaculata, and Orthetrum sabina were evaluated against the 4th instar larvae of the dengue vector mosquito, Aedes aegypti, under laboratory conditions. The consumption of the mosquito larvae was evaluated at three water volume levels viz., 1 liter, 2 liter and 3 liter. Results: The number of Ae. aegypti larvae consumed varied significantly among the five species, and at different levels of water volume (P< 0.01). However, the interaction between odonate nymphs and the water volumes was statistically non-significant (P> 0.05). Ischnura forcipata consumed the highest number of Ae. aegypti larvae (n=56) followed by A. parthenope (n=47) and B. geminate (n=46). The number of larvae consumed was decreased with increasing search area or water volume, and the highest predation was observed at 1-liter water volume. Conclusion: The odonate nymphs could be a good source of biological agents for the management of the mosquitoes at larval stages. PMID:27308283

  5. Development of dengue DNA vaccines.

    PubMed

    Danko, Janine R; Beckett, Charmagne G; Porter, Kevin R

    2011-09-23

    Vaccination with plasmid DNA against infectious pathogens including dengue is an active area of investigation. By design, DNA vaccines are able to elicit both antibody responses and cellular immune responses capable of mediating long-term protection. Great technical improvements have been made in dengue DNA vaccine constructs and trials are underway to study these in the clinic. The scope of this review is to highlight the rich history of this vaccine platform and the work in dengue DNA vaccines accomplished by scientists at the Naval Medical Research Center. This work resulted in the only dengue DNA vaccine tested in a clinical trial to date. Additional advancements paving the road ahead in dengue DNA vaccine development are also discussed.

  6. Human Immune Response to Dengue Infections

    DTIC Science & Technology

    1989-07-31

    lhuman Immune Response to Dengue Infections 12. PERSONAL AUTHOR(S) Francis A. Ennis 13a. TYPE OF REPORT 13b. TIME COVERED T14. DATE OF REPORT (Year, Month...Stimulation with live dengue virus of peripheral blood mononuclear cells from a dengue 4-immune donor generated virus-specific serotype cross-reactive CD4- CD8...class I-restricted cytotoxic T lymphocytes (CL) capable of lysing dengue virus-infected autologous fibroblasts and cells pulsed with dengue I

  7. Costs of Three Wolbachia Infections on the Survival of Aedes aegypti Larvae under Starvation Conditions

    PubMed Central

    Ross, Perran A.; Endersby, Nancy M.; Hoffmann, Ary A.

    2016-01-01

    The mosquito Aedes aegypti, the principal vector of dengue virus, has recently been infected experimentally with Wolbachia: intracellular bacteria that possess potential as dengue biological control agents. Wolbachia depend on their hosts for nutrients they are unable to synthesize themselves. Consequently, competition between Wolbachia and their host for resources could reduce host fitness under the competitive conditions commonly experienced by larvae of Ae. aegypti in the field, hampering the invasion of Wolbachia into natural mosquito populations. We assess the survival and development of Ae. aegypti larvae under starvation conditions when infected with each of three experimentally-generated Wolbachia strains: wMel, wMelPop and wAlbB, and compare their fitness to wild-type uninfected larvae. We find that all three Wolbachia infections reduce the survival of larvae relative to those that are uninfected, and the severity of the effect is concordant with previously characterized fitness costs to other life stages. We also investigate the ability of larvae to recover from extended food deprivation and find no effect of Wolbachia on this trait. Aedes aegypti larvae of all infection types were able to resume their development after one month of no food, pupate rapidly, emerge at a large size, and exhibit complete cytoplasmic incompatibility and maternal transmission. A lowered ability of Wolbachia-infected larvae to survive under starvation conditions will increase the threshold infection frequency required for Wolbachia to establish in highly competitive natural Ae. aegypti populations and will also reduce the speed of invasion. This study also provides insights into survival strategies of larvae when developing in stressful environments. PMID:26745630

  8. Costs of Three Wolbachia Infections on the Survival of Aedes aegypti Larvae under Starvation Conditions.

    PubMed

    Ross, Perran A; Endersby, Nancy M; Hoffmann, Ary A

    2016-01-01

    The mosquito Aedes aegypti, the principal vector of dengue virus, has recently been infected experimentally with Wolbachia: intracellular bacteria that possess potential as dengue biological control agents. Wolbachia depend on their hosts for nutrients they are unable to synthesize themselves. Consequently, competition between Wolbachia and their host for resources could reduce host fitness under the competitive conditions commonly experienced by larvae of Ae. aegypti in the field, hampering the invasion of Wolbachia into natural mosquito populations. We assess the survival and development of Ae. aegypti larvae under starvation conditions when infected with each of three experimentally-generated Wolbachia strains: wMel, wMelPop and wAlbB, and compare their fitness to wild-type uninfected larvae. We find that all three Wolbachia infections reduce the survival of larvae relative to those that are uninfected, and the severity of the effect is concordant with previously characterized fitness costs to other life stages. We also investigate the ability of larvae to recover from extended food deprivation and find no effect of Wolbachia on this trait. Aedes aegypti larvae of all infection types were able to resume their development after one month of no food, pupate rapidly, emerge at a large size, and exhibit complete cytoplasmic incompatibility and maternal transmission. A lowered ability of Wolbachia-infected larvae to survive under starvation conditions will increase the threshold infection frequency required for Wolbachia to establish in highly competitive natural Ae. aegypti populations and will also reduce the speed of invasion. This study also provides insights into survival strategies of larvae when developing in stressful environments.

  9. Identification of Essential Containers for Aedes Larval Breeding to Control Dengue in Dhaka, Bangladesh

    PubMed Central

    Ferdousi, Farhana; Yoshimatsu, Shoji; Ma, Enbo; Sohel, Nazmul; Wagatsuma, Yukiko

    2015-01-01

    Dengue fever (DF), one of the most important emerging arboviral diseases, is transmitted through the bite of container breeding mosquitoes Aedes aegypti and Aedes albopictus. A household entomological survey was conducted in Dhaka from August through October 2000 to inspect water-holding containers in indoor, outdoor, and rooftop locations for Aedes larvae. The objective of this study was to determine mosquito productivity of each container type and to identify some risk factors of households infested with Aedes larvae. Of 9,222 households inspected, 1,306 (14.2%) were positive for Aedes larvae. Of 38,777 wet containers examined, 2,272 (5.8%) were infested with Aedes larvae. Containers used to hold water, such as earthen jars, tanks, and drums were the most common containers for larval breeding. Tires in outdoor and rooftop locations of the households were also important for larval breeding. Although present in abundance, buckets were of less importance. Factors such as independent household, presence of a water storage system in the house, and fully/partly shaded outdoors were found to be significantly associated with household infestation of Aedes larvae. Identification and subsequent elimination of the most productive containers in a given area may potentially reduce mosquito density to below a level at which dengue transmission may be halted. PMID:26865829

  10. Mortality Predictors in Patients with Severe Dengue in the State of Amazonas, Brazil

    PubMed Central

    Pinto, Rosemary Costa; de Castro, Daniel Barros; de Albuquerque, Bernardino Cláudio; Sampaio, Vanderson de Souza; dos Passos, Ricardo Augusto; da Costa, Cristiano Fernandes; Sadahiro, Megumi; Braga, José Ueleres

    2016-01-01

    Dengue is a major public health problem in tropical and subtropical areas worldwide. There is a lack of information on the risk factors for death due to severe dengue fever in developing countries, including Brazil where the state of Amazonas is located. This knowledge is important for decision making and the implementation of effective measures for patient care. This study aimed to identify factors associated with death among patients with severe dengue, in Amazonas from 2001 to 2013. We conducted a retrospective cohort study based on secondary data from the epidemiological surveillance of dengue provided by the Fundação de Vigilância em Saúde do Amazonas, FVS (Health Surveillance Foundation) of the Secretaria de Saúde do Amazonas, SUSAM (Health Secretariat of the State of Amazonas). Data on dengue cases were obtained from the SINAN (Notifiable Diseases Information System) and SIM (Mortality Information System) databases. We selected cases of severe dengue with laboratory confirmation, including dengue-related deaths of residents in the state of Amazonas from January 1, 2001, to December 31, 2013. The explanatory variables analyzed were sex, age, level of education, spontaneous hemorrhagic manifestations, plasma extravasation and platelet count. Patients who died due to severe dengue had more hematuria, gastrointestinal bleeding, and thrombocytopenia than the survivors. Considering the simultaneous effects of demographic and clinical characteristics with a multiple logistic regression model, it was observed that the factors associated with death were age >55 years (odds ratio [OR] 4.98), gastrointestinal bleeding (OR 10.26), hematuria (OR 5.07), and thrombocytopenia (OR 2.55). Gastrointestinal bleeding was the clinical sign most strongly associated with death, followed by hematuria and age >55 years. The study results showed that the best predictor of death from severe dengue is based on the characteristic of age >55 years, together with the clinical signs of

  11. Mortality Predictors in Patients with Severe Dengue in the State of Amazonas, Brazil.

    PubMed

    Pinto, Rosemary Costa; Castro, Daniel Barros de; Albuquerque, Bernardino Cláudio de; Sampaio, Vanderson de Souza; Passos, Ricardo Augusto Dos; Costa, Cristiano Fernandes da; Sadahiro, Megumi; Braga, José Ueleres

    2016-01-01

    Dengue is a major public health problem in tropical and subtropical areas worldwide. There is a lack of information on the risk factors for death due to severe dengue fever in developing countries, including Brazil where the state of Amazonas is located. This knowledge is important for decision making and the implementation of effective measures for patient care. This study aimed to identify factors associated with death among patients with severe dengue, in Amazonas from 2001 to 2013. We conducted a retrospective cohort study based on secondary data from the epidemiological surveillance of dengue provided by the Fundação de Vigilância em Saúde do Amazonas, FVS (Health Surveillance Foundation) of the Secretaria de Saúde do Amazonas, SUSAM (Health Secretariat of the State of Amazonas). Data on dengue cases were obtained from the SINAN (Notifiable Diseases Information System) and SIM (Mortality Information System) databases. We selected cases of severe dengue with laboratory confirmation, including dengue-related deaths of residents in the state of Amazonas from January 1, 2001, to December 31, 2013. The explanatory variables analyzed were sex, age, level of education, spontaneous hemorrhagic manifestations, plasma extravasation and platelet count. Patients who died due to severe dengue had more hematuria, gastrointestinal bleeding, and thrombocytopenia than the survivors. Considering the simultaneous effects of demographic and clinical characteristics with a multiple logistic regression model, it was observed that the factors associated with death were age >55 years (odds ratio [OR] 4.98), gastrointestinal bleeding (OR 10.26), hematuria (OR 5.07), and thrombocytopenia (OR 2.55). Gastrointestinal bleeding was the clinical sign most strongly associated with death, followed by hematuria and age >55 years. The study results showed that the best predictor of death from severe dengue is based on the characteristic of age >55 years, together with the clinical signs of

  12. Dengue human infection models to advance dengue vaccine development.

    PubMed

    Larsen, Christian P; Whitehead, Stephen S; Durbin, Anna P

    2015-12-10

    Dengue viruses (DENV) currently infect approximately 400 million people each year causing millions to seek care and overwhelming the health care infrastructure in endemic areas. Vaccines to prevent dengue and therapeutics to treat dengue are not currently available. The efficacy of the most advanced candidate vaccine against symptomatic dengue in general and DENV-2 in particular was much lower than expected, despite the ability of the vaccine to induce neutralizing antibody against all four DENV serotypes. Because seroconversion to the DENV serotypes following vaccination was thought to be indicative of induced protection, these results have made it more difficult to assess which candidate vaccines should or should not be evaluated in large studies in endemic areas. A dengue human infection model (DHIM) could be extremely valuable to down-select candidate vaccines or therapeutics prior to engaging in efficacy trials in endemic areas. Two DHIM have been developed to assess the efficacy of live attenuated tetravalent (LATV) dengue vaccines. The first model, developed by the Laboratory of Infectious Diseases at the U. S. National Institutes of Health, utilizes a modified DENV-2 strain DEN2Δ30. This virus was derived from the DENV-2 Tonga/74 that caused only very mild clinical infection during the outbreak from which it was recovered. DEN2Δ30 induced viremia in 100%, rash in 80%, and neutropenia in 27% of the 30 subjects to whom it was given. The Walter Reed Army Institute of Research (WRAIR) is developing a DHIM the goal of which is to identify DENV that cause symptomatic dengue fever. WRAIR has evaluated seven viruses and has identified two that meet dengue fever criteria. Both of these models may be very useful in the evaluation and down-selection of candidate dengue vaccines and therapeutics.

  13. Energy vs. essential fatty acids: what do scallop larvae (Argopecten purpuratus) need most?

    PubMed

    Nevejan, Nancy; Saez, Iris; Gajardo, Gonzalo; Sorgeloos, Patrick

    2003-04-01

    Larvae of the Chilean-Peruvian scallop Argopecten purpuratus were fed a Dunaliella tertiolecta diet (Dun-diet) supplemented with lipid emulsions, rich in 20:5n-3 (EmEPA), 22:6n-3 (EmDHA) or in saturated fatty acids (EmCOCO). A mixed algal diet of Isochrysis galbana (T-iso) and Chaetoceros neogracile served as a positive control (St-diet). Lipid supplementation to the Dun-diet improved the larval growth and increased the percentage of eyed larvae significantly, compared to the non-supplemented Dun-diet because of the extra energy supplied and not because of its fatty acid composition. No significant differences were observed between supplementation with EmEPA, EmDHA or EmCOCO. A mixture of 20% EmEPA+20% EmDHA (40% EmHUFA) was more efficient in raising the total lipid content in larvae than 40% EmCOCO. Both emulsions increased the triacylglycerol content in larvae compared to the non-supplemented Dun-diet. The best result, however, was obtained with the St-diet, probably because of a more suitable 18:2n-6/18:3n-3 ratio and a higher level of arachidonic acid. A positive relationship between the 18:2n-6/18:3n-3 ratio and the larval performance was found. No significant difference was observed in post-settlement larval size or percentage of metamorphosed larvae between the St-diet and the St-diet supplemented with 20% EmHUFA or 20% EmCOCO. The metamorphosed larvae had a constant DHA/EPA ratio of 3.7, independent from the diet, which suggested a metabolic control of the two fatty acids and a species-dependency of the ratio.

  14. Vertical infestation of the dengue vectors Aedes aegypti and Aedes albopictus in apartments in Kuala Lumpur, Malaysia.

    PubMed

    Roslan, Muhammad Aidil; Shafie, Aziz; Ngui, Romano; Lim, Yvonne Ai Lian; Sulaiman, Wan Yusoff Wan

    2013-12-01

    Dengue is a serious public health problem in Malaysia. The aim of this study was to compare the vertical infestation of Aedes population in 2 apartments in Kuala Lumpur with different status of dengue incidence (i.e., high-dengue-incidence area and area with no reported dengue cases). The study was also conducted to assess the relationship between environmental factors such as rainfall, temperature, and humidity and Aedes population that may influence Aedes infestation. Surveillance with a mosquito larvae trapping device was conducted for 28 continuous weeks (January to July 2012) in Vista Angkasa (VA) and Inderaloka (IL) apartments located in Kuala Lumpur, Malaysia. The results indicated that both Aedes spp. could be found from ground to higher floor levels of the apartments, with Aedes aegypti being more predominant than Ae. albopictus. Data based on mixed and single breeding of Aedes spp. on different floors did not show any significant difference. Both rainfall (R3; i.e., the amount of rainfall collected during the previous 3 wk before the surveillance period began) and RH data showed significant relationship with the number of Aedes larvae collected in VA and IL. No significant difference was found between the numbers of Aedes larvae in both study areas as well as maximum and minimum temperatures. Results also indicated adaptations of Ae. aegypti to the ecosystem at each elevation of high-rise buildings, with Ae. albopictus staying inside of apartment units.

  15. Dengue and other flavivirus infections.

    PubMed

    Choumet, V; Desprès, Ph

    2015-08-01

    Flaviviruses are responsible for yellow fever, Zika fever and dengue, all of which are major human diseases found in tropical regions of the globe. They are zoonoses with a transmission cycle that involves primates as reservoirs and mosquitoes of the genus Aedes as vectors. The recent upsurge of urban epidemics of yellow fever, Zika fever and dengue has involved human-to-human transmission with mosquitoes as the vector. This paper is primarily concerned with dengue, which has become the pre-eminent arbovirosis in terms of public health.

  16. The Buen Pastor cemetery in Trujillo, Venezuela: measuring dengue vector output from a public area.

    PubMed

    Abe, Mayumi; McCall, P J; Lenhart, Audrey; Villegas, Elci; Kroeger, Axel

    2005-06-01

    As vector control of dengue typically targets individual households to eliminate breeding sites or control adult mosquitoes during epidemics, public spaces are frequently neglected. To investigate the importance of such places as sources of dengue vectors, a study of Aedes aegypti productivity in a cemetery in northern Venezuela, using standard entomological indices for assessing dengue vector infestations, was carried out in the wet season in May 2003. Containers were found on 72.8% of graves; 44% of the containers held water and in 46.9% of these we found A. aegypti larvae and/or pupae. The average density of Aedes-infested containers was 39 per hectare. There were no significant differences in infestation rates between container types (vases, planters or others) or materials (cement, plastic, glass, etc.). Containers with 1-5 l of water held the greatest proportion of the pupae found in the cemetery (46.7%); containers with <100 ml of water contained no pupae. The mean number of pupae produced in the cemetery was estimated at 4185 pupae/ha per 48 h and the daily output of potential vector mosquitoes from the entire cemetery was calculated at approximately 3000 females per day. These mosquitoes presumably left the cemetery to feed in the nearby communities, thus thwarting the environmental management and health education programmes that had reduced household dengue vector infestations. The study shows the importance of public places as sources of dengue vectors in urban areas, and the need to include such areas in vector control programmes.

  17. Dengue Fever Seroprevalence and Risk Factors, Texas–Mexico Border, 2004

    PubMed Central

    López, Jose Luis Robles; Ramirez, Josue; Cifuentes, Enrique; Rothenberg, Stephen J.; Hunsperger, Elizabeth A.; Moore, Chester G.; Brussolo, Regina M.; Villarreal, Norma A.; Haddad, Brent M.

    2007-01-01

    Reported autochthonous dengue fever transmission in the United States has been limited to 5 south Texas border counties since 1980. We conducted a cross-sectional serosurvey in Brownsville, Texas, and Matamoros, Tamaulipas, Mexico (n = 600), in 2004 to assess dengue seroprevalence. Recent dengue infection was detected in 2% (95% confidence interval [CI] 0.5%–3.5%) and 7.3% (95% CI 4.3%–10.3%) of residents in Brownsville and Matamoros, respectively. Past infection was detected in 40% (95% CI 34%–45%) of Brownsville residents and 78% (95% CI 74%–83%) of Matamoros residents. For recent infection, only weekly family income <$100 was a significant predictor (adjusted odds ratio 3.2, 95% CI 1.3–8.0). Risk factors that predicted past dengue infection were presence of larval habitat, absence of air-conditioning and street drainage, and weekly family income <$100. Mosquito larvae were present in 30% of households in both cities. Our results show that dengue fever is endemic in this area of the southern Texas–Mexico border. PMID:18257990

  18. Dengue fever seroprevalence and risk factors, Texas-Mexico border, 2004.

    PubMed

    Brunkard, Joan Marie; Robles López, Jose Luis; Ramirez, Josue; Cifuentes, Enrique; Rothenberg, Stephen J; Hunsperger, Elizabeth A; Moore, Chester G; Brussolo, Regina M; Villarreal, Norma A; Haddad, Brent M

    2007-10-01

    Reported autochthonous dengue fever transmission in the United States has been limited to 5 south Texas border counties since 1980. We conducted a cross-sectional serosurvey in Brownsville, Texas, and Matamoros, Tamaulipas, Mexico (n = 600), in 2004 to assess dengue seroprevalence. Recent dengue infection was detected in 2% (95% confidence interval [CI] 0.5%-3.5%) and 7.3% (95% CI 4.3%-10.3%) of residents in Brownsville and Matamoros, respectively. Past infection was detected in 40% (95% CI 34%-45%) of Brownsville residents and 78% (95% CI 74%-83%) of Matamoros residents. For recent infection, only weekly family income dengue infection were presence of larval habitat, absence of air-conditioning and street drainage, and weekly family income larvae were present in 30% of households in both cities. Our results show that dengue fever is endemic in this area of the southern Texas-Mexico border.

  19. Challenges encountered using standard vector control measures for dengue in Boa Vista, Brazil

    PubMed Central

    Valle, Denise

    2014-01-01

    Abstract Problem In 2010, dengue virus (DENV) serotype–4 was detected during a dengue outbreak in the Amazonian city of Boa Vista. At that time Brazil was already endemic for DENV-1, DENV-2 and DENV-3. This was the first time DENV-4 was observed in the country after it was initially detected and eliminated in 1981. Approach To hinder the spread of DENV-4 throughout Brazil, standard vector control measures were intensified. Vector control professionals visited 56 837 households in 22 out of 31 districts of Boa Vista, to eliminate mosquito-breeding sites. Water storage containers were treated with the larvicide diflubenzuron, and deltamethrin was sprayed for adult Aedes aegypti mosquitoes. Fifteen days later, a second larvae survey and additional deltamethrin applications were performed. Local setting In Brazil, dengue vector control is managed at all three government levels. Regular surveillance of Aedes aegypti is done four to six times a year to strengthen mosquito control activities in areas with high-vector density. Educational dengue control campaigns in communities are scarce, especially between outbreaks. Relevant changes In spite of extensive implementation of all standard control actions recommended by the Brazilian dengue control programme, only a slight decrease in mosquito density was detected. Lessons learnt There is a need to redesign all levels of dengue control. Public consultation and engagement, behaviour change and actions that go beyond technical impositions are required. Vector control programme managers need to reflect on what constitutes good practices and whether intermittent information campaigns are effective measures for dengue prevention and control. PMID:25378760

  20. Dengue and dengue haemorrhagic fever: implications of host genetics.

    PubMed

    Chaturvedi, Umeshc; Nagar, Rachna; Shrivastava, Richa

    2006-07-01

    Little is known of the role of human leucocyte antigen (HLA) alleles or non-HLA alleles in determining resistance, susceptibility or the severity of acute viral infections. Dengue fever (DF) and dengue haemorrhagic fever (DHF) are suitable models for immunogenetic studies, yet only superficial efforts have been made to study dengue disease to date. DF and DHF can be caused by both primary and secondary infection by any of the four serotypes of the dengue virus. Differences in host susceptibility to infectious disease and disease severity cannot be attributed solely to the virus virulence. Variations in immune response, often associated with polymorphism in the human genome, can now be detected. Data on the influence of human genes in DF and DHF are discussed here in relation to (1) associations between HLA polymorphism and dengue disease susceptibility or resistance, (2) protective alleles influencing progression to severe disease, (3) alleles restricting CD4(+) and CD8(+) T lymphocytes, and (4) non-HLA genetic factors that may contribute to DHF evolution. Recent discoveries regarding genetic associations in other viral infections may provide clues to understanding the development of end-stage complications in dengue disease. The scanty positive data presented here indicate a need for detailed genetic studies in different ethnic groups in different countries during the acute phase of DF and DHF on a larger number of patients.

  1. Dengue fever and dengue haemorrhagic fever in adolescents and adults.

    PubMed

    Tantawichien, Terapong

    2012-05-01

    Dengue fever (DF) is endemic in tropical and subtropical zones and the prevalence is increasing across South-east Asia, Africa, the Western Pacific and the Americas. In recent years, the spread of unplanned urbanisation, with associated substandard housing, overcrowding and deterioration in water, sewage and waste management systems, has created ideal conditions for increased transmission of the dengue virus in tropical urban centres. While dengue infection has traditionally been considered a paediatric disease, the age distribution of dengue has been rising and more cases have been observed in adolescents and adults. Furthermore, the development of tourism in the tropics has led to an increase in the number of tourists who become infected, most of whom are adults. Symptoms and risk factors for dengue haemorrhagic fever (DHF) and severe dengue differ between children and adults, with co-morbidities and incidence in more elderly patients associated with greater risk of mortality. Treatment options for DF and DHF in adults, as for children, centre round fluid replacement (either orally or intravenously, depending on severity) and antipyretics. Further data are needed on the optimal treatment of adult patients.

  2. Pseudomonas aeruginosa KUN2, extracellular toxins-A potential source for the control of dengue vector.

    PubMed

    Lalithambika, B; Vani, C

    2016-01-01

    Dengue fever is one of the serious health disease transmitted by Aedes spp mosquitoes. The incidence of dengue has increased dramatically around the world in recent decades. Vector control is one of the important strategies practiced for the control of dengue fever. The emergence of resistance among vectors against the existing insecticides has raised new challenges. The aim of the present study was to identify the larvicidal activity of extracellular toxins from Pseudomonas spp for the control of dengue vector, Aedes aegypti. Bacterial isolates KUN1, KUN2, KUN3, KUN4, and KUBS were isolated from rhizosphere soil of the agricultural fields in Coimbatore, Tamil Nadu. Lyophilized culture supernatant of KUN2 (24, 48, and 72 h culture) and the solvent extracts from the diethyl ether, petroleum ether, chloroform and ethyl acetate were tested against the IV instar larvae of Ae. aegypti. Morphological and biochemical characterization of KUN2 showed its resemblance to Pseudomonas spp. Further, characterization by molecular methods confirmed it as Pseudomonas aeruginosa. Lyophilized culture supernatant of KUN2 showed more toxicity towards the larvae of Ae. aegypti when grown in the modified medium. Secondary metabolite from the petroleum ether extract was found more toxic to the Ae. aegypti larvae even at low concentration (50 μg/ml). The supernatant of 48 h culture of KUN2 recorded 100% larvicidal activity when compared to other isolates. Further, the rate of mortality was 100% at 24 h when treated with 100 μg/ml of petroleum ether extract of KUN2. Among the isolates used for the control of Ae. aegypti, the isolate KUN2 showed increased larvicidal activity when grown in the modified medium. The maximum larval mortality was observed in the solvent extract of petroleum ether. The mortality of the larvae might be due to the effect of the toxic compound present in the extract which would have entered the larvae through its cuticle damaging its whole system and obstructing

  3. Recent advances in understanding dengue

    PubMed Central

    Yacoub, Sophie; Mongkolsapaya, Juthathip; Screaton, Gavin

    2016-01-01

    Dengue is an emerging threat to billions of people worldwide. In the last 20 years, the incidence has increased four-fold and this trend appears to be continuing. Caused by one of four viral serotypes, dengue can present as a wide range of clinical phenotypes with the severe end of the spectrum being defined by a syndrome of capillary leak, coagulopathy, and organ impairment. The pathogenesis of severe disease is thought to be in part immune mediated, but the exact mechanisms remain to be defined. The current treatment of dengue relies on supportive measures with no licensed therapeutics available to date. There have been recent advances in our understanding of a number of areas of dengue research, of which the following will be discussed in this review: the drivers behind the global dengue pandemic, viral structure and epitope binding, risk factors for severe disease and its pathogenesis, as well as the findings of recent clinical trials including therapeutics and vaccines. We conclude with current and future dengue control measures and key areas for future research. PMID:26918159

  4. Dengue viruses – an overview

    PubMed Central

    Bäck, Anne Tuiskunen; Lundkvist, Åke

    2013-01-01

    Dengue viruses (DENVs) cause the most common arthropod-borne viral disease in man with 50–100 million infections per year. Because of the lack of a vaccine and antiviral drugs, the sole measure of control is limiting the Aedes mosquito vectors. DENV infection can be asymptomatic or a self-limited, acute febrile disease ranging in severity. The classical form of dengue fever (DF) is characterized by high fever, headache, stomach ache, rash, myalgia, and arthralgia. Severe dengue, dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS) are accompanied by thrombocytopenia, vascular leakage, and hypotension. DSS, which can be fatal, is characterized by systemic shock. Despite intensive research, the underlying mechanisms causing severe dengue is still not well understood partly due to the lack of appropriate animal models of infection and disease. However, even though it is clear that both viral and host factors play important roles in the course of infection, a fundamental knowledge gap still remains to be filled regarding host cell tropism, crucial host immune response mechanisms, and viral markers for virulence. PMID:24003364

  5. Dengue vaccines: problems and prospects.

    PubMed

    Chaturvedi, U C; Shrivastava, Richa; Nagar, Rachna

    2005-05-01

    The extent of cumulative disease burden caused by dengue virus has attained an unprecedented level in recent times with sharp increase in the size of human population at risk. Dengue disease presents highly complex medical, economic and ecologic problems. The surge in publications on the development of dengue vaccines, taking advantage of new generation of biotechnology techniques indicates the profound interest and urgency in the scientific and medical communities in combating this disease. This review summarizes the importance of critical subjects like pathogenesis of dengue haemorrhagic fever and inadequacy of animal model that have adversely affected dengue vaccine development. Further, the remarkable progresses so far made in dengue vaccine research not only employing a diverse range of new strategies but also re-using old techniques to improve the existing vaccines, have been presented. The efficacy and safety of some of the new vaccine candidates have been evaluated and proven in human preclinical/clinical trials. Besides the technical advancement in vaccine development, vaccine safety and vaccine formulation have been examined.

  6. Dot enzyme immunoassay: an alternative diagnostic aid for dengue fever and dengue haemorrhagic fever.

    PubMed Central

    Cardosa, M. J.; Tio, P. H.

    1991-01-01

    A dot enzyme immunoassay (DEIA) for the detection of antibodies to dengue virus was tested for use as a tool in the presumptive diagnosis of dengue fever and dengue haemorrhagic fever. Paired sera from the following groups of patients were tested using the DEIA and the haemagglutination inhibition (HI) test: those with primary dengue fever; those experiencing a second dengue infection; and febrile patients who did not have dengue. The data obtained show that the DEIA can be effectively used at a serum dilution of 1:1000 to confirm presumptive recent dengue in patients with a second dengue infection. However, demonstration of seroconversion proved necessary for patients with primary dengue. At a serum dilution of 1:1000 the DEIA has a specificity of 97.3%. The role of this simple and rapid test in improving the effectivity of programmes for the control of dengue virus infection is discussed. PMID:1786623

  7. [Spatial interpolation of Aedes aegypti larvae abundance for locating infestation foci].

    PubMed

    Niño, Larry

    2011-06-01

    Design and implement a surveillance method for locating Aedes aegypti infestation foci with the use of larvae traps and spatial interpolation techniques, which facilitate the ongoing estimation of vector abundance in the area by counting the individuals collected in the study area. A total of 228 larvae traps were installed--at a rate of one per block--in the most densely populated area of commune five of Villavicencio (Meta). With regionalized information on larvae abundance, spatial interpolations were conducted with the Voronoi polygon, ordinary kriging, and inverse distance weighting techniques. An alternative method for the surveillance of dengue vectors is presented. This method is based on the use of larvae traps and spatial interpolation techniques to obtain area maps supported by specific observations. The results show that this strategy is better than the indices normally used, since it facilitates continuous visualization of the level of vector infestation and consequently, the risk of dengue transmission, based on the extent of A. aegypti infestation. Implementation of this strategy is expected to contribute to more effective planning, optimization, and evaluation of prevention and control activities.

  8. Outdoor spatial spraying against dengue: A false sense of security among inhabitants of Hermosillo, Mexico

    PubMed Central

    Castro-Luque, Lucía; Díaz-Caravantes, Rolando; Walker, Kathleen R.; Hayden, Mary H.; Ernst, Kacey C.

    2017-01-01

    Background Government-administered adulticiding is frequently conducted in response to dengue transmission worldwide. Anecdotal evidence suggests that spraying may create a “false sense of security” for residents. Our objective was to determine if there was an association between residents’ reporting outdoor spatial insecticide spraying as way to prevent dengue transmission and both their reported frequency of dengue prevention practices and household entomological indices in Hermosillo, Mexico. Methodology/Principal findings A non-probabilistic survey of 400 households was conducted in August 2014. An oral questionnaire was administered to an adult resident and the outer premises of the home were inspected for water-holding containers and presence of Ae. aegypti larvae and pupae. Self-reported frequency of prevention practices were assessed among residents who reported outdoor spatial spraying as a strategy to prevent dengue (n = 93) and those who did not (n = 307). Mixed effects negative binomial regression was used to assess associations between resident’s reporting spraying as a means to prevent dengue and container indices. Mixed effects logistic regression was used to determine associations with presence/absence of larvae and pupae. Those reporting spatial spraying disposed of trash less frequently and spent less time indoors to avoid mosquitoes. They also used insecticides and larvicides more often and covered their water containers more frequently. Their backyards had more containers positive for Ae. aegypti (RR = 1.92) and there was a higher probability of finding one or more Ae. aegypti pupae (OR = 2.20). Survey respondents that reported spatial spraying prevented dengue were more likely to be older and were exposed to fewer media sources regarding prevention. Conclusions/Significance The results suggest that the perception that outdoor spatial spraying prevents dengue is associated with lower adoption of prevention practices and higher

  9. Outdoor spatial spraying against dengue: A false sense of security among inhabitants of Hermosillo, Mexico.

    PubMed

    Reyes-Castro, Pablo A; Castro-Luque, Lucía; Díaz-Caravantes, Rolando; Walker, Kathleen R; Hayden, Mary H; Ernst, Kacey C

    2017-05-01

    Government-administered adulticiding is frequently conducted in response to dengue transmission worldwide. Anecdotal evidence suggests that spraying may create a "false sense of security" for residents. Our objective was to determine if there was an association between residents' reporting outdoor spatial insecticide spraying as way to prevent dengue transmission and both their reported frequency of dengue prevention practices and household entomological indices in Hermosillo, Mexico. A non-probabilistic survey of 400 households was conducted in August 2014. An oral questionnaire was administered to an adult resident and the outer premises of the home were inspected for water-holding containers and presence of Ae. aegypti larvae and pupae. Self-reported frequency of prevention practices were assessed among residents who reported outdoor spatial spraying as a strategy to prevent dengue (n = 93) and those who did not (n = 307). Mixed effects negative binomial regression was used to assess associations between resident's reporting spraying as a means to prevent dengue and container indices. Mixed effects logistic regression was used to determine associations with presence/absence of larvae and pupae. Those reporting spatial spraying disposed of trash less frequently and spent less time indoors to avoid mosquitoes. They also used insecticides and larvicides more often and covered their water containers more frequently. Their backyards had more containers positive for Ae. aegypti (RR = 1.92) and there was a higher probability of finding one or more Ae. aegypti pupae (OR = 2.20). Survey respondents that reported spatial spraying prevented dengue were more likely to be older and were exposed to fewer media sources regarding prevention. The results suggest that the perception that outdoor spatial spraying prevents dengue is associated with lower adoption of prevention practices and higher entomological risk. This provides some support to the hypothesis that spraying may

  10. Acute disseminated encephalomyelitis in dengue viral infection.

    PubMed

    Wan Sulaiman, Wan Aliaa; Inche Mat, Liyana Najwa; Hashim, Hasnur Zaman; Hoo, Fan Kee; Ching, Siew Mooi; Vasudevan, Ramachandran; Mohamed, Mohd Hazmi; Basri, Hamidon

    2017-09-01

    Dengue is the most common arboviral disease affecting many countries worldwide. An RNA virus from the flaviviridae family, dengue has four antigenically distinct serotypes (DEN-1-DEN-4). Neurological involvement in dengue can be classified into dengue encephalopathy immune-mediated syndromes, encephalitis, neuromuscular or dengue muscle dysfunction and neuro-ophthalmic involvement. Acute disseminated encephalomyelitis (ADEM) is an immune mediated acute demyelinating disorder of the central nervous system following recent infection or vaccination. This monophasic illness is characterised by multifocal white matter involvement. Many dengue studies and case reports have linked ADEM with dengue virus infection but the association is still not clear. Therefore, this article is to review and discuss concerning ADEM in dengue as an immune-medicated neurological complication; and the management strategy required based on recent literature. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Scientists Create Mosquitoes Resistant to Dengue Virus

    MedlinePlus

    ... fullstory_163019.html Scientists Create Mosquitoes Resistant to Dengue Virus Hope is to eventually make the bugs ... say they have created mosquitoes resistant to the dengue virus, which might eventually help control the spread ...

  12. Field observation on the efficacy of Toxorhynchites splendens (Wiedemann) as a biocontrol agent against Aedes albopictus (Skuse) larvae in a cemetery.

    PubMed

    Nyamah, M A; Sulaiman, S; Omar, B

    2011-08-01

    This study explored the efficacy of Toxorhynchites splendens, predator of Aedes albopictus as a biocontrol agent. There was a negative correlation between Ae. albopictus larval population and Tx. splendens larval population in ovitraps (r=-0.287, R²=0.0821). The correlation is higher between the mean number of Ae. albopictus larvae per ovitrap and the number of Tx. splendens larvae in an ovitrap (r=-0.987, R²=0.9737). Larvae of Tx. splendens were observed to co-exist with larvae of Ae. albopictus and Culex fuscocephala in the ovitraps placed in the study area. The existence of Tx. splendens larvae in the study area coincides with their habit, preferring to breed in bamboo stumps. A total of 480 ovitraps were inspected for 30-week study period and 281 ovitraps were positive with Ae. albopictus larvae respectively. There was a significant difference between numbers of ovitrap positive for Ae. albopictus larvae with number of Tx. splendens larvae in the ovitraps (ANOVA, F((4,475)) 2.655, p<0.05). Of 281 ovitraps positive with Ae. albopictus larvae, 255 ovitraps contained only one Tx. splendens larva each. Only one ovitrap contained four, the most number of Tx. splendens larvae (p< 0.05). Thus, Tx. splendens could be utilised as an alternative for dengue vector control programme.

  13. Safety Testing of Dengue-1 and Dengue-3 Seeds for Human Challenges, Unattenuated

    DTIC Science & Technology

    1987-03-16

    62770A870 AC 029 11. TITL.E (Include Security Classiftcation) (U) Safety Testing of Dengue -1 and Dengue -𔃽 Seeds for Human Challenges, Unatteuad 12...safety testing of a lot of dengue virus type 3 designated as: Dengue Virus Type 3 (Non-Attenuated) Strain CH-53489 Utilizing the testing procedures...Virus Strain: Dengue Virus *rype 3 (Non-Attenuated) Strain: CH-53489 B. Live Virus Vaccine Pool Designation: MFG Date: April J.984, LOT No. 1 C

  14. Dengue Virus Seroconversion in Travelers to Dengue-Endemic Areas.

    PubMed

    Olivero, Rosemary M; Hamer, Davidson H; MacLeod, William B; Benoit, Christine M; Sanchez-Vegas, Carolina; Jentes, Emily S; Chen, Lin H; Wilson, Mary E; Marano, Nina; Yanni, Emad A; Ooi, Winnie W; Karchmer, Adolf W; Kogelman, Laura; Barnett, Elizabeth D

    2016-11-02

    We conducted a prospective study to measure dengue virus (DENV) antibody seroconversion in travelers to dengue-endemic areas. Travelers seen in the Boston Area Travel Medicine Network planning to visit dengue-endemic countries for ≥ 2 weeks were enrolled from 2009 to 2010. Pre- and post-travel blood samples and questionnaires were collected. Post-travel sera were tested for anti-DENV IgG by indirect IgG enzyme-linked immunosorbent assay (ELISA) and anti-DENV IgM by capture IgM ELISA. Participants with positive post-travel anti-DENV IgG or IgM were tested for pre-travel anti-DENV IgG and IgM; they were excluded from the seroconversion calculation if either pre-travel anti-DENV IgG or IgM were positive. Paired sera and questionnaires were collected for 62% (589/955) of enrolled travelers. Most participants were 19-64 years of age, female, and white. The most common purposes of travel were tourism and visiting friends and relatives; most trips were to Asia or Africa. Median length of travel was 21 days. DENV antibody seroconversion by either anti-DENV IgM or IgG ELISA was 2.9-6.8%; lower range percent excluded potential false-positive anti-DENV IgG due to receipt of yellow fever or Japanese encephalitis vaccines at enrollment; upper range percent excluded proven false-positive anti-DENV IgM. Eighteen percent of those with seroconversion reported dengue-like symptoms. Seroconversion was documented for travel to Africa as well as countries and regions known to be highly dengue endemic (India, Brazil, southeast Asia). Given widespread risk of dengue, travel medicine counseling should include information on risk of dengue in endemic areas and advice on preventing insect bites and seeking prompt medical attention for febrile illness.

  15. Dengue Antibody and Zika: Friend or Foe?

    PubMed

    Durbin, Anna P

    2016-10-01

    Zika virus is a mosquito-borne Flavivirus related to dengue that is rapidly spreading through the Americas. This outbreak is occurring in dengue-endemic areas where the population has acquired antibodies to dengue. Recent studies reveal that preexisting dengue antibodies may have opposite effects on Zika infection, transmission, and clinical outcome. Discerning these effects is critical to a better understanding of Zika pathogenesis and the prevention of future outbreaks.

  16. Reviewing Dengue: Still a Neglected Tropical Disease?

    PubMed Central

    Horstick, Olaf; Tozan, Yesim; Wilder-Smith, Annelies

    2015-01-01

    Dengue is currently listed as a “neglected tropical disease” (NTD). But is dengue still an NTD or not? Classifying dengue as an NTD may carry advantages, but is it justified? This review considers the criteria for the definition of an NTD, the current diverse lists of NTDs by different stakeholders, and the commonalities and differences of dengue with other NTDs. We also review the current research gaps and research activities and the adequacy of funding for dengue research and development (R&D) (2003–2013). NTD definitions have been developed to a higher precision since the early 2000s, with the following main features: NTDs are characterised as a) poverty related, b) endemic to the tropics and subtropics, c) lacking public health attention, d) having poor research funding and shortcomings in R&D, e) usually associated with high morbidity but low mortality, and f) often having no specific treatment available. Dengue meets most of these criteria, but not all. Although dengue predominantly affects resource-limited countries, it does not necessarily only target the poor and marginalised in those countries. Dengue increasingly attracts public health attention, and in some affected countries it is now a high profile disease. Research funding for dengue has increased exponentially in the past two decades, in particular in the area of dengue vaccine development. However, despite advances in dengue research, dengue epidemics are increasing in frequency and magnitude, and dengue is expanding to new areas. Specific treatment and a highly effective vaccine remain elusive. Major research gaps exist in the area of integrated surveillance and vector control. Hence, although dengue differs from many of the NTDs, it still meets important criteria commonly used for NTDs. The current need for increased R&D spending, shared by dengue and other NTDs, is perhaps the key reason why dengue should continue to be considered an NTD. PMID:25928673

  17. [Hemorrhagic dengue fever after trip to Malaysia].

    PubMed

    Hafner, C; Koellner, K; Vogt, T; Landthaler, M; Szeimies, R-M

    2006-08-01

    A 39-year-old patient developed a disseminated rash with scattered petechiae, fever, malaise and arthralgia after a trip to Malaysia. The patient displayed increasing dengue IgG titers and borderline dengue IgM titers. Dengue fever with a hemorrhagic course is a rare condition in adult patients. Patients who have previously had dengue fever and retained non-neutralizing heterotypic antibodies are more likely to develop this complication via the phenomenon of antibody-dependent enhancement.

  18. Field Worker Evaluation of Dengue Vector Surveillance Methods: Factors That Determine Perceived Ease, Difficulty, Value, and Time Effectiveness in Australia and Malaysia.

    PubMed

    Azil, Aishah H; Ritchie, Scott A; Williams, Craig R

    2015-10-01

    This qualitative study aimed to describe field worker perceptions, evaluations of worth, and time costs of routine dengue vector surveillance methods in Cairns (Australia), Kuala Lumpur and Petaling District (Malaysia). In Cairns, the BG-Sentinel trap is a favored method for field workers because of its user-friendliness, but is not as cost-efficient as the sticky ovitrap. In Kuala Lumpur, the Mosquito Larvae Trapping Device is perceived as a solution for the inaccessibility of premises to larval surveys. Nonetheless, the larval survey method is retained in Malaysia for prompt detection of dengue vectors. For dengue vector surveillance to be successful, there needs to be not only technical, quantitative evaluations of method performance but also an appreciation of how amenable field workers are to using particular methods. Here, we report novel field worker perceptions of dengue vector surveillance methods in addition to time analysis for each method. © 2014 APJPH.

  19. Randomness of Dengue Outbreaks on the Equator.

    PubMed

    Chen, Yirong; Cook, Alex R; Lim, Alisa X L

    2015-09-01

    A simple mathematical model without seasonality indicated that the apparently chaotic dengue epidemics in Singapore have characteristics similar to epidemics resulting from chance. Randomness as a sufficient condition for patterns of dengue epidemics in equatorial regions calls into question existing explanations for dengue outbreaks there.

  20. Acanthocephala Larvae parasitizing Ameiva ameiva ameiva (Linnaeus, 1758) (Squamata: Teiidae).

    PubMed

    Macedo, Lilian Cristina; Melo, Francisco Tiago de Vasconcelos; Ávila-Pires, Teresa Cristina Sauer; Giese, Elane Guerreiro; Santos, Jeannie Nascimento Dos

    2016-03-11

    Knowledge concerning the taxonomy and biology of species of Acanthocephala, helminth parasites of the helminth species of the phylum Acanthocephala, parasites of lizards in Brazilian Amazonia, is still insufficient, but reports of Acanthocephala in reptiles are becoming increasingly common in the literature. Cystacanth-stage Acanthocephalan larvae have been found in the visceral peritoneum during necropsy of Ameiva ameiva ameivalizards from the "Osvaldo Rodrigues da Cunha" Herpetology Collection of the Emílio Goeldi Museum, Belém, Pará, Brazil. The aim of this study was to present the morphological study of the Acanthocephala larvae found in A. ameiva ameiva lizard.

  1. Acanthocephala Larvae parasitizing Ameiva ameiva ameiva (Linnaeus, 1758) (Squamata: Teiidae).

    PubMed

    Macedo, Lilian Cristina; Melo, Francisco Tiago de Vasconcelos; Ávila-Pires, Teresa Cristina Sauer; Giese, Elane Guerreiro; dos Santos, Jeannie Nascimento

    2016-01-01

    Knowledge concerning the taxonomy and biology of species of Acanthocephala, helminth parasites of the helminth species of the phylum Acanthocephala, parasites of lizards in Brazilian Amazonia, is still insufficient, but reports of Acanthocephala in reptiles are becoming increasingly common in the literature. Cystacanth-stage Acanthocephalan larvae have been found in the visceral peritoneum during necropsy of Ameiva ameiva ameivalizards from the "Osvaldo Rodrigues da Cunha" Herpetology Collection of the Emílio Goeldi Museum, Belém, Pará, Brazil. The aim of this study was to present the morphological study of the Acanthocephala larvae found in A. ameiva ameiva lizard.

  2. New Early Cambrian bilaterian embryos and larvae from China

    NASA Astrophysics Data System (ADS)

    Steiner, Michael; Zhu, Maoyan; Li, Guoxiang; Qian, Yi; Erdtmann, Bernd-D.

    2004-10-01

    Although knowledge of exceptional Cambrian fossil Lagerstätten has increased dramatically, relatively little information has been uncovered about the early ontogeny of ancient Metazoa. Here we describe new phosphatized eggs and embryos, partly indicating germ band formation, and the earliest known larvae of early bilaterians. Developmental sequences are reconstructed for Pseudooidesem>- and tetramerous-type embryos. Together with these developmental sequences, patterns of germ band formation, irregular “radial” cleavage types, and unciliated larva with serial divisions and a posterior segment indicate affinities with protostomes, most probably within an ancestral arthropodan lineage.

  3. Dengue maculopathy: a case report.

    PubMed

    Tan, S Y; Kumar, G; Surrun, S K; Ong, Y Y

    2007-01-01

    Dengue fever is endemic in many countries of South East Asia. In spite of the occasional epidemics, dengue maculopathy remains a rare entity. A 31-year-old gentleman was admitted with a 6-day history of fever, generalised rash, headache and myalgia after a trip to Malaysia. There were no bleeding manifestations. The lowest platelet count was 71 x 10,000/ml, the haematocrit was 42.7%, and dengue serology was positive. On the 8th day of illness, he complained of bilateral blurred vision. Detailed visual examination showed visual acuity of right eye 6/30 and left eye 6/50. Fundoscopy revealed dilated veins, hyperaemic optic discs, flame and blot haemorrhages, soft exudates and macular ischaemia. After a course of high-dose steroids, the visual acuity as well as colour vision improved markedly. The pathology of maculopathy is not obvious in this case, but an immunological reaction is suspected. There is a risk of residual visual impairment, and there is no definitive treatment. The use of high-dose steroids seemed to improve visual acuity and colour vision. However, it is not known whether immunosuppression improves the prognosis. Time for resolution is from 8 weeks to 4 months. Since there is an increase in the incidence of dengue fever in our region, coupled with rising international travel, one could postulate that global incidence of dengue-related maculopathy may become significant. Ocular complications associated with dengue fever are rare but may result in permanent visual impairment. Dengue fever should be suspected in travellers, particularly those returning from endemic areas, and they should be systematically screened for maculopathy when visual disturbances arise.

  4. Climate and Dengue Transmission: Evidence and Implications

    PubMed Central

    Comrie, Andrew C.; Ernst, Kacey

    2013-01-01

    Background: Climate influences dengue ecology by affecting vector dynamics, agent development, and mosquito/human interactions. Although these relationships are known, the impact climate change will have on transmission is unclear. Climate-driven statistical and process-based models are being used to refine our knowledge of these relationships and predict the effects of projected climate change on dengue fever occurrence, but results have been inconsistent. Objective: We sought to identify major climatic influences on dengue virus ecology and to evaluate the ability of climate-based dengue models to describe associations between climate and dengue, simulate outbreaks, and project the impacts of climate change. Methods: We reviewed the evidence for direct and indirect relationships between climate and dengue generated from laboratory studies, field studies, and statistical analyses of associations between vectors, dengue fever incidence, and climate conditions. We assessed the potential contribution of climate-driven, process-based dengue models and provide suggestions to improve their performance. Results and Discussion: Relationships between climate variables and factors that influence dengue transmission are complex. A climate variable may increase dengue transmission potential through one aspect of the system while simultaneously decreasing transmission potential through another. This complexity may at least partly explain inconsistencies in statistical associations between dengue and climate. Process-based models can account for the complex dynamics but often omit important aspects of dengue ecology, notably virus development and host–species interactions. Conclusion: Synthesizing and applying current knowledge of climatic effects on all aspects of dengue virus ecology will help direct future research and enable better projections of climate change effects on dengue incidence. Citation: Morin CW, Comrie AC, Ernst KC. 2013. Climate and dengue transmission

  5. Rare occurrence of natural transovarial transmission of dengue virus and elimination of infected foci as a possible intervention method.

    PubMed

    Angel, Annette; Angel, Bennet; Joshi, Vinod

    2016-03-01

    Transovarial transmission of dengue virus has been studied in 33 districts of Rajasthan, India. Small proportion (1.09%) of breeding containers positive for the virus and their elimination has been demonstrated as a possible intervention method of disease control. Dengue virus was isolated from individual mosquitoes employing Indirect Fluorescence Antibody Test and Reverse Transcriptase Polymerase Chain Reaction. Out of 1,30,525 containers examined only 1432(1.09%) showed transovarially transmitted virus activity. Elimination of larvae from all the 1432 virus positive containers resulted in substantial control over prospective transmission of dengue. The study highlights rarity of transovarial transmission under natural conditions and sensitizes whether elimination of vertically infected foci could be used as a new intervention method.

  6. Presence of three dengue serotypes in Ouagadougou (Burkina Faso): research and public health implications.

    PubMed

    Ridde, Valéry; Agier, Isabelle; Bonnet, Emmanuel; Carabali, Mabel; Dabiré, Kounbobr Roch; Fournet, Florence; Ly, Antarou; Meda, Ivlabèhiré Bertrand; Parra, Beatriz

    2016-04-05

    The significant malaria burden in Africa has often eclipsed other febrile illnesses. Burkina Faso's first dengue epidemic occurred in 1925 and the most recent in 2013. Yet there is still very little known about dengue prevalence, its vector proliferation, and its poverty and equity impacts. An exploratory cross-sectional survey was performed from December 2013 to January 2014. Six primary healthcare centers in Ouagadougou were selected based on previously reported presence of Flavivirus. All patients consulting with fever or having had fever within the previous week and with a negative rapid diagnostic test (RDT) for malaria were invited to participate. Sociodemographic data, healthcare use and expenses, mobility, health-related status, and vector control practices were captured using a questionnaire. Blood samples of every eligible subject were obtained through finger pricks during the survey for dengue RDT using SD BIOLINE Dengue Duo (NS1Ag and IgG/IgM)® and to obtain blood spots for reverse transcription polymerase chain reaction (RT-PCR) analysis. In a sample of randomly selected yards and those of patients, potential Aedes breeding sites were found and described. Larvae were collected and brought to the laboratory to monitor the emergence of adults and identify the species. Of the 379 subjects, 8.7 % (33/379) had positive RDTs for dengue. Following the 2009 WHO classification, 38.3 % (145/379) had presumptive, probable, or confirmed dengue, based on either clinical symptoms or laboratory testing. Of 60 samples tested by RT-PCR (33 from the positive tests and 27 from the subsample of negatives), 15 were positive. The serotypes observed were DENV2, DENV3, and DENV4. Odds of dengue infection in 15-to-20-year-olds and persons over 50 years were 4.0 (CI 95 %: 1.0-15.6) and 7.7 (CI 95 %: 1.6-37.1) times higher, respectively, than in children under five. Average total spending for a dengue episode was 13 771 FCFA [1 300-67 300 FCFA] (1$US = 478 FCFA). On average

  7. Human Immune Response to Dengue Infections

    DTIC Science & Technology

    1988-07-31

    Security Classification) (U) Human Immune Response to Dengue Infections 12. PERSONAL AUTHOR(S) Francis A. Ennis 13a. TYPE OF’REPORTn 13b. TIME COVERED 14...8217SUBJECT TERMS (Continue on reverse if necessary and identify by Nock rumber) FIELD GROUP SUB-GROUP RA .1, Dengue virus, T lymphopytes. 06 03 InB-GROP1.In...responses to dengue antigens in vitro to elucidate the possible role of T lymphocytes in the pathogeneeis of dengue hemorrhagic fever and dengue

  8. A comparative analysis of the relative efficacy of vector-control strategies against dengue fever.

    PubMed

    Amaku, Marcos; Coutinho, Francisco Antonio Bezerra; Raimundo, Silvia Martorano; Lopez, Luis Fernandez; Nascimento Burattini, Marcelo; Massad, Eduardo

    2014-03-01

    Dengue is considered one of the most important vector-borne infection, affecting almost half of the world population with 50 to 100 million cases every year. In this paper, we present one of the simplest models that can encapsulate all the important variables related to vector control of dengue fever. The model considers the human population, the adult mosquito population and the population of immature stages, which includes eggs, larvae and pupae. The model also considers the vertical transmission of dengue in the mosquitoes and the seasonal variation in the mosquito population. From this basic model describing the dynamics of dengue infection, we deduce thresholds for avoiding the introduction of the disease and for the elimination of the disease. In particular, we deduce a Basic Reproduction Number for dengue that includes parameters related to the immature stages of the mosquito. By neglecting seasonal variation, we calculate the equilibrium values of the model's variables. We also present a sensitivity analysis of the impact of four vector-control strategies on the Basic Reproduction Number, on the Force of Infection and on the human prevalence of dengue. Each of the strategies was studied separately from the others. The analysis presented allows us to conclude that of the available vector control strategies, adulticide application is the most effective, followed by the reduction of the exposure to mosquito bites, locating and destroying breeding places and, finally, larvicides. Current vector-control methods are concentrated on mechanical destruction of mosquitoes' breeding places. Our results suggest that reducing the contact between vector and hosts (biting rates) is as efficient as the logistically difficult but very efficient adult mosquito's control.

  9. Application of revised dengue classification criteria as a severity marker of dengue viral infection in Indonesia.

    PubMed

    Basuki, Parwati Setiono; Budiyanto; Puspitasari, Dwiyanti; Husada, Dominicus; Darmowandowo, Widodo; Ismoedijanto; Soegijanto, Soegeng; Yamanaka, Atsushi

    2010-09-01

    A prospective study of dengue infected patients at Dr.Soetomo Hospital pediatric ward was carried out from October 2008 to April 2009 to evaluate the revised dengue classification system proposed by the Dengue Control (DENCO), for early detection of severe dengue infected patients using the WHO classification system for comparison, with the addition of clinical interventions as a tool to grade for severity. One hundred forty-five patients were included in the study. Using the WHO classification system, 122 cases (84.1%) were classified as having non-severe dengue, of which 70 (48.3%) were classified as having dengue fever (DF), 39 (26.9%) as having dengue hemorrhagic fever (DHF) grade I, and 13 (9%) as having DHF grade II. Twenty-three (15.9%) were classified as having severe dengue, of which 16 (11%) were classified as having DHF grade III and 7 (4.8%) as having DHF grade IV. With clinical interventions included, 8 cases (6.6%) originally classified as having non-severe dengue infection were reclassified as having severe infection (sensitivity = 74%, specificity = 100%, likelihood ratio (-) = 0.26). Using the new dengue classification system, 117 cases (80.7%) were classified as having non-severe dengue infection, of which 79 (54.5%) were classified as having dengue without warning signs and 38 (26.2%) were classified as having dengue with warning signs, while 28 (19.3%) were classified as having severe dengue infection. Using clinical intervention, 4 cases (3.4%) which were originally classified as having non-severe dengue infection were reclassified as having severe dengue infection (sensitivity = 88%, specificity = 99%, likelihood ratio (+) = 98.88, likelihood ratio (-) = 0.13). Binary logistic regression showed the revised dengue classification system (p = 0.000, Wald:22.446) was better in detecting severe dengue infections than the WHO classification system (p = 0.175, Wald:6.339).

  10. Critical issues in dengue vaccine development.

    PubMed

    Thomas, Stephen J; Endy, Timothy P

    2011-10-01

    Dengue is currently an expanding global health problem. Development of an effective tetravalent dengue vaccine is considered a high public health priority. The uniqueness of the dengue viruses (DENVs) and the spectrum of disease resulting from infection has made dengue vaccine development difficult. This review focuses on the current critical issues in dengue vaccine development. DENVs are arboviral flaviviruses transmitted by Aedes mosquitoes causing a spectrum of clinical disease. DENV infections are a significant global health problem; the WHO estimates that more than 120 countries have endemic DENV transmission resulting in 70-500 million infections, 2.1 million clinically severe cases, and 21 000 deaths annually. There are currently no licensed antivirals or vaccines to treat or prevent dengue. The DENV-host interaction of infection is unique with severe disease a consequence of sequential dengue infection, viral immune evasion, host antibody enhancement, host immune activation, and genetic predisposition. This unique pathogen-host interaction complicates dengue vaccine development and creates provocative questions in vaccine development such as identifying markers of protective immunogenicity, the potential role of antibody in vaccine failures, and the possible impact of large-scale vaccination on the evolution of wild-type DENV. Dengue is a unique and complex disease; developing a dengue vaccine has proven equally complex. In this review, the authors discuss issues that will prove to be critical to the success or failure of the dengue vaccine development effort.

  11. Reemergence of Dengue in Southern Texas, 2013

    PubMed Central

    Thomas, Dana L.; Santiago, Gilberto A.; Abeyta, Roman; Hinojosa, Steven; Torres-Velasquez, Brenda; Adam, Jessica K.; Evert, Nicole; Caraballo, Elba; Hunsperger, Elizabeth; Muñoz-Jordán, Jorge L.; Smith, Brian; Banicki, Alison; Tomashek, Kay M.; Gaul, Linda

    2016-01-01

    During a dengue epidemic in northern Mexico, enhanced surveillance identified 53 laboratory-positive cases in southern Texas; 26 (49%) patients acquired the infection locally, and 29 (55%) were hospitalized. Of 83 patient specimens that were initially IgM negative according to ELISA performed at a commercial laboratory, 14 (17%) were dengue virus positive by real-time reverse transcription PCR performed at the Centers for Disease Control and Prevention. Dengue virus types 1 and 3 were identified, and molecular phylogenetic analysis demonstrated close identity with viruses that had recently circulated in Mexico and Central America. Of 51 household members of 22 dengue case-patients who participated in household investigations, 6 (12%) had been recently infected with a dengue virus and reported no recent travel, suggesting intrahousehold transmission. One household member reported having a recent illness consistent with dengue. This outbreak reinforces emergence of dengue in southern Texas, particularly when incidence is high in northern Mexico. PMID:27191223

  12. Trends in clinical trials of dengue vaccine

    PubMed Central

    Marimuthu, Priya; Ravinder, Jamuna Rani

    2016-01-01

    Dengue is one of the most important vector-borne disease and an increasing problem worldwide because of current globalization trends. Roughly, half the world's population lives in dengue endemic countries, and nearly 100 million people are infected annually with dengue. India has the highest burden of the disease with 34% of the global cases. In the context of an expanding and potentially fatal infectious disease without effective prevention or specific treatment, the public health value of a protective vaccine is clear. There is no licensed dengue vaccine is available still, but several vaccines are under development. Keeping in view the rise in dengue prevalence globally, there is a need to increase clinical drug and vaccine research on dengue. This paper briefly reviews on the development and current status of dengue vaccine to provide information to policymakers, researchers, and public health experts to design and implement appropriate vaccine for prophylactic intervention. PMID:27843790

  13. Transfusion support in patients with dengue fever.

    PubMed

    Kaur, Paramjit; Kaur, Gagandeep

    2014-09-01

    Dengue fever has emerged as a global public health problem in the recent decades. The clinical spectrum of the disease ranges from dengue fever to dengue hemorrhagic fever and dengue shock syndrome. The disease is characterized by increased capillary permeability, thrombocytopenia and coagulopathy. Thrombocytopenia with hemorrhagic manifestations warrants platelet transfusions. There is lack of evidence-based guidelines for transfusion support in patients with dengue fever. This contributes to inappropriate use of blood components and blood centers constantly face the challenge of inventory management during dengue outbreaks. The current review is aimed to highlight the role of platelets and other blood components in the management of dengue. The review was performed after searching relevant published literature in PubMed, Science Direct, Google scholar and various text books and journal articles.

  14. Reemergence of Dengue in Southern Texas, 2013.

    PubMed

    Thomas, Dana L; Santiago, Gilberto A; Abeyta, Roman; Hinojosa, Steven; Torres-Velasquez, Brenda; Adam, Jessica K; Evert, Nicole; Caraballo, Elba; Hunsperger, Elizabeth; Muñoz-Jordán, Jorge L; Smith, Brian; Banicki, Alison; Tomashek, Kay M; Gaul, Linda; Sharp, Tyler M

    2016-06-01

    During a dengue epidemic in northern Mexico, enhanced surveillance identified 53 laboratory-positive cases in southern Texas; 26 (49%) patients acquired the infection locally, and 29 (55%) were hospitalized. Of 83 patient specimens that were initially IgM negative according to ELISA performed at a commercial laboratory, 14 (17%) were dengue virus positive by real-time reverse transcription PCR performed at the Centers for Disease Control and Prevention. Dengue virus types 1 and 3 were identified, and molecular phylogenetic analysis demonstrated close identity with viruses that had recently circulated in Mexico and Central America. Of 51 household members of 22 dengue case-patients who participated in household investigations, 6 (12%) had been recently infected with a dengue virus and reported no recent travel, suggesting intrahousehold transmission. One household member reported having a recent illness consistent with dengue. This outbreak reinforces emergence of dengue in southern Texas, particularly when incidence is high in northern Mexico.

  15. Points for Consideration for dengue vaccine introduction - recommendations by the Dengue Vaccine Initiative.

    PubMed

    Lim, Jacqueline Kyungah; Lee, Yong-Seok; Wilder-Smith, Annelies; Thiry, Georges; Mahoney, Richard; Yoon, In-Kyu

    2016-01-01

    Dengue is a public health problem in the tropics and subtropics. There are several vaccine candidates in clinical development. However, there may be gaps in the new vaccine introduction after vaccine licensure before it becomes available in developing countries. In anticipation of the first dengue vaccine candidate to be licensed, Dengue Vaccine Initiative (DVI) and, its predecessor, Pediatric Dengue Vaccine Initiative (PDVI) have been working on points for consideration to accelerate evidence-based dengue vaccine introduction, once a vaccine becomes available. In this paper, we review the history of PDVI and its successor, the DVI, and elaborate on the points of consideration for dengue vaccine introduction.

  16. Dengue virus identification by transmission electron microscopy and molecular methods in fatal dengue hemorrhagic fever.

    PubMed

    Limonta, D; Falcón, V; Torres, G; Capó, V; Menéndez, I; Rosario, D; Castellanos, Y; Alvarez, M; Rodríguez-Roche, R; de la Rosa, M C; Pavón, A; López, L; González, K; Guillén, G; Diaz, J; Guzmán, M G

    2012-12-01

    Dengue virus is the most significant virus transmitted by arthropods worldwide and may cause a potentially fatal systemic disease named dengue hemorrhagic fever. In this work, dengue virus serotype 4 was detected in the tissues of one fatal dengue hemorrhagic fever case using electron immunomicroscopy and molecular methods. This is the first report of dengue virus polypeptides findings by electron immunomicroscopy in human samples. In addition, not-previously-documented virus-like particles visualized in spleen, hepatic, brain, and pulmonary tissues from a dengue case are discussed.

  17. [Society, economy, inequities and dengue].

    PubMed

    Kouri, Gustavo; Pelegrino, José L; Munster, Blanca María; Guzmán, María G

    2007-01-01

    Dengue and dengue hemorrhagic fever in the Americas have been on the rise throughout the 1990s, with the highest number -over one million cases- reported in 2002. This paper analyzed the situation of dengue in the region and discussed the determining factors that account for the rise of the disease, making emphasis on socioeconomic factors, such as poverty, inequality, migrations and the lack of access to basic services, which are the most influential in perpetuating this disease in most countries. Considering that a safe and accessible vaccine is now unavailable, basic principles of vector control combined with political willingness, inter-sectoral involvement, active community participation and the tightening of health legislation were also examined as the only viable solution at present.

  18. Climate and dengue transmission: evidence and implications.

    PubMed

    Morin, Cory W; Comrie, Andrew C; Ernst, Kacey

    2013-01-01

    Climate influences dengue ecology by affecting vector dynamics, agent development, and mosquito/human interactions. Although these relationships are known, the impact climate change will have on transmission is unclear. Climate-driven statistical and process-based models are being used to refine our knowledge of these relationships and predict the effects of projected climate change on dengue fever occurrence, but results have been inconsistent. We sought to identify major climatic influences on dengue virus ecology and to evaluate the ability of climate-based dengue models to describe associations between climate and dengue, simulate outbreaks, and project the impacts of climate change. We reviewed the evidence for direct and indirect relationships between climate and dengue generated from laboratory studies, field studies, and statistical analyses of associations between vectors, dengue fever incidence, and climate conditions. We assessed the potential contribution of climate-driven, process-based dengue models and provide suggestions to improve their performance. Relationships between climate variables and factors that influence dengue transmission are complex. A climate variable may increase dengue transmission potential through one aspect of the system while simultaneously decreasing transmission potential through another. This complexity may at least partly explain inconsistencies in statistical associations between dengue and climate. Process-based models can account for the complex dynamics but often omit important aspects of dengue ecology, notably virus development and host-species interactions. Synthesizing and applying current knowledge of climatic effects on all aspects of dengue virus ecology will help direct future research and enable better projections of climate change effects on dengue incidence.

  19. Controlling Dengue with Vaccines in Thailand

    PubMed Central

    Chao, Dennis L.; Halstead, Scott B.; Halloran, M. Elizabeth; Longini, Ira M.

    2012-01-01

    Background Dengue is a mosquito-borne infectious disease that constitutes a growing global threat with the habitat expansion of its vectors Aedes aegyti and A. albopictus and increasing urbanization. With no effective treatment and limited success of vector control, dengue vaccines constitute the best control measure for the foreseeable future. With four interacting dengue serotypes, the development of an effective vaccine has been a challenge. Several dengue vaccine candidates are currently being tested in clinical trials. Before the widespread introduction of a new dengue vaccine, one needs to consider how best to use limited supplies of vaccine given the complex dengue transmission dynamics and the immunological interaction among the four dengue serotypes. Methodology/Principal Findings We developed an individual-level (including both humans and mosquitoes), stochastic simulation model for dengue transmission and control in a semi-rural area in Thailand. We calibrated the model to dengue serotype-specific infection, illness and hospitalization data from Thailand. Our simulations show that a realistic roll-out plan, starting with young children then covering progressively older individuals in following seasons, could reduce local transmission of dengue to low levels. Simulations indicate that this strategy could avert about 7,700 uncomplicated dengue fever cases and 220 dengue hospitalizations per 100,000 people at risk over a ten-year period. Conclusions/Significance Vaccination will have an important role in controlling dengue. According to our modeling results, children should be prioritized to receive vaccine, but adults will also need to be vaccinated if one wants to reduce community-wide dengue transmission to low levels. PMID:23145197

  20. Controlling dengue with vaccines in Thailand.

    PubMed

    Chao, Dennis L; Halstead, Scott B; Halloran, M Elizabeth; Longini, Ira M

    2012-01-01

    Dengue is a mosquito-borne infectious disease that constitutes a growing global threat with the habitat expansion of its vectors Aedes aegyti and A. albopictus and increasing urbanization. With no effective treatment and limited success of vector control, dengue vaccines constitute the best control measure for the foreseeable future. With four interacting dengue serotypes, the development of an effective vaccine has been a challenge. Several dengue vaccine candidates are currently being tested in clinical trials. Before the widespread introduction of a new dengue vaccine, one needs to consider how best to use limited supplies of vaccine given the complex dengue transmission dynamics and the immunological interaction among the four dengue serotypes. We developed an individual-level (including both humans and mosquitoes), stochastic simulation model for dengue transmission and control in a semi-rural area in Thailand. We calibrated the model to dengue serotype-specific infection, illness and hospitalization data from Thailand. Our simulations show that a realistic roll-out plan, starting with young children then covering progressively older individuals in following seasons, could reduce local transmission of dengue to low levels. Simulations indicate that this strategy could avert about 7,700 uncomplicated dengue fever cases and 220 dengue hospitalizations per 100,000 people at risk over a ten-year period. Vaccination will have an important role in controlling dengue. According to our modeling results, children should be prioritized to receive vaccine, but adults will also need to be vaccinated if one wants to reduce community-wide dengue transmission to low levels.

  1. Overview: Pyraloidea larvae (Insecta: Lepidoptera)

    USDA-ARS?s Scientific Manuscript database

    The larvae of pyraloid or snout moths are pests to many crops and stored products and rank as among the most destructive pests to graminaceous crops such as corn, sugarcane, and rice. On the other hand, some larvae have been investigated and used for the biological control of noxious terrestrial a...

  2. Policymakers' views on dengue fever/dengue haemorrhagic fever and the need for dengue vaccines in four southeast Asian countries.

    PubMed

    DeRoeck, Denise; Deen, Jacqueline; Clemens, John D

    2003-12-08

    A survey of policymakers and other influential professionals in four southeast Asian countries (Cambodia, Indonesia, Philippines and Vietnam) was conducted to determine policymakers' views on the public health importance of dengue fever and dengue haemorrhagic fever (DHF), the need for a vaccine and the determinants influencing its potential introduction. The survey, which involved face-to-face interviews with policymakers, health programme managers, researchers, opinion leaders and other key informants, revealed an almost uniformly high level of concern about dengue fever/DHF and a high perceived need for a dengue vaccine. Several characteristics of the disease contribute to this high sense of priority, including its geographic spread, occurrence in outbreaks, the recurrent risk of infection each dengue season, its severity and the difficulty in diagnosis and management, its urban predominance, its burden on hospitals, and its economic toll on governments and families. Research felt to be key to future decision-making regarding dengue vaccine introduction include: disease surveillance studies, in-country vaccine trials or pilot projects, and studies on the economic burden of dengue and the cost-effectiveness of dengue vaccines. The results suggest favourable conditions for public and private sector markets for dengue vaccines and the need for creative financing strategies to ensure their accessibility to poor children in dengue-endemic countries.

  3. Occurrence of Natural Vertical Transmission of Dengue-2 and Dengue-3 Viruses in Aedes aegypti and Aedes albopictus in Fortaleza, Ceará, Brazil

    PubMed Central

    Martins, Victor Emanuel Pessoa; Alencar, Carlos Henrique; Kamimura, Michel Tott; de Carvalho Araújo, Fernanda Montenegro; De Simone, Salvatore Giovanni; Dutra, Rosa Fireman; Guedes, Maria Izabel Florindo

    2012-01-01

    Background Aedes aegypti and Aedes albopictus perform an important role in the transmission of the dengue virus to human populations, particularly in the tropical and subtropical regions of the world. Despite a lack of understanding in relation to the maintenance of the dengue virus in nature during interepidemic periods, the vertical transmission of the dengue virus in populations of A. aegypti and A. albopictus appears to be of significance in relation to the urban scenario of Fortaleza. Methods From March 2007 to July 2009 collections of larvae and pupae of Aedes spp were carried out in 40 neighborhoods of Fortaleza. The collections yielded 3,417 (91%) A. aegypti mosquitoes and 336 (9%) A. albopictus mosquitoes. Only pools containing females, randomly chosen, were submitted to the following tests indirect immunofluorescence (virus isolation), RT-PCR/nested-PCR and nucleotide sequencing at the C-prM junction of the dengue virus genome. Results The tests on pool 34 (35 A. albopictus mosquitoes) revealed with presence of DENV-3, pool 35 (50 A. aegypti mosquitoes) was found to be infected with DENV-2, while pool 49 (41 A. albopictus mosquitoes) revealed the simultaneous presence of DENV-2 and DENV-3. Based on the results obtained, there was a minimum infection rate of 0.5 for A. aegypti and 9.4 for A. albopictus. The fragments of 192 bp and 152 bp related to DENV-3, obtained from pools 34 and 49, was registered in GenBank with the access codes HM130699 and JF261696, respectively. Conclusions This study recorded the first natural evidence of the vertical transmission of the dengue virus in populations of A. aegypti and A. albopictus collected in Fortaleza, Ceará State, Brazil, opening a discuss on the epidemiological significance of this mechanism of viral transmission in the local scenario, particularly with respect to the maintenance of these viruses in nature during interepidemic periods. PMID:22848479

  4. Larval stress alters dengue virus susceptibility in Aedes aegypti (L.) adult females.

    PubMed

    Kang, David S; Alcalay, Yehonatan; Lovin, Diane D; Cunningham, Joanne M; Eng, Matthew W; Chadee, Dave D; Severson, David W

    2017-10-01

    In addition to genetic history, environmental conditions during larval stages are critical to the development, success and phenotypic fate of the Aedes aegypti mosquito. In particular, previous studies have shown a strong genotype-by-environment component to adult mosquito body size in response to optimal vs stressed larval conditions. Here, we expand upon those results by investigating the effects of larval-stage crowding and nutritional limitation on the susceptibility of a recent field isolate of Aedes aegypti to dengue virus serotype-2. Interestingly, female mosquitoes from larvae subjected to a stressed regime exhibited significantly reduced susceptibility to disseminated dengue infection 14days post infection compared to those subjected to optimal regimes. Short term survivorship post-infected blood feeding was not significantly different. As with body size, dengue virus susceptibility of a mosquito population is determined by a combination of genetic and environmental factors and is likely maintained by balancing selection. Here, we provide evidence that under different environmental conditions, the innate immune response of field-reared mosquitoes exhibits a large range of phenotypic variability with regard to dengue virus susceptibility. Further, as with body size, our results suggest that mosquitoes reared under optimal laboratory conditions, as employed in all mosquito-pathogen studies to date, may not always be realistic proxies for natural populations. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Family leader empowerment program using participatory learning process for dengue vector control.

    PubMed

    Pengvanich, Veerapong

    2011-02-01

    Assess the performance of the empowerment program using participatory learning process for the control of Dengue vector The program focuses on using the leaders of families as the main executer of the vector control protocol. This quasi-experimental research utilized the two-group pretest-posttest design. The sample group consisted of 120 family leaders from two communities in Mueang Municipality, Chachoengsao Province. The research was conducted during an 8-week period between April and June 2010. The data were collected and analyzed based on frequency, percentage, mean, paired t-test, and independent t-test. The result was evaluated by comparing the difference between the mean prevalence index of mosquito larvae before and after the process implementation in terms of the container index (CI) and the house index (HI). After spending eight weeks in the empowerment program, the family leader's behavior in the aspect of Dengue vector control has improved. The Container Index and the House Index were found to decrease with p = 0.05 statistical significance. The reduction of CI and HI suggested that the program worked well in the selected communities. The success of the Dengue vector control program depended on cooperation and participation of many groups, especially the families in the community When the family leaders have good attitude and are capable of carrying out the vector control protocol, the risk factor leading to the incidence of Dengue rims infection can be reduced.

  6. Natural vertical transmission of dengue viruses by Aedes aegypti in Bolivia

    PubMed Central

    Le Goff, G.; Revollo, J.; Guerra, M.; Cruz, M.; Barja Simon, Z.; Roca, Y.; Vargas Florès, J.; Hervé, J.P.

    2011-01-01

    The natural transmission of dengue virus from an infected female mosquito to its progeny, namely the vertical transmission, was researched in wild caught Aedes aegypti during an important outbreak in the town of Santa Cruz de la Sierra, Bolivia. Mosquitoes were collected at the preimaginal stages (eggs, larvae and pupae) then reared up to adult stage for viral detection using molecular methods. Dengue virus serotypes 1 and 3 were found to be co-circulating with significant higher prevalence in male than in female mosquitoes. Of the 97 pools of Ae. aegypti (n = 635 male and 748 female specimens) screened, 14 pools, collected in February-May in 2007, were found positive for dengue virus infection: five DEN-1 and nine DEN-3. The average true infection rate (TIR) and minimum infection rate (MIR) were respectively 1.08% and 1.01%. These observations suggest that vertical transmission of dengue virus may be detected in vectors at the peak of an outbreak as well as several months before an epidemic occurs in human population. PMID:21894270

  7. Natural vertical transmission of dengue viruses by Aedes aegypti in Bolivia.

    PubMed

    Le Goff, G; Revollo, J; Guerra, M; Cruz, M; Barja Simon, Z; Roca, Y; Vargas Florès, J; Hervé, J P

    2011-08-01

    The natural transmission of dengue virus from an infected female mosquito to its progeny, namely the vertical transmission, was researched in wild caught Aedes aegypti during an important outbreak in the town of Santa Cruz de la Sierra, Bolivia. Mosquitoes were collected at the preimaginal stages (eggs, larvae and pupae) then reared up to adult stage for viral detection using molecular methods. Dengue virus serotypes 1 and 3 were found to be co-circulating with significant higher prevalence in male than in female mosquitoes. Of the 97 pools of Ae. aegypti (n = 635 male and 748 female specimens) screened, 14 pools, collected in February-May in 2007, were found positive for dengue virus infection: five DEN-1 and nine DEN-3. The average true infection rate (TIR) and minimum infection rate (MIR) were respectively 1.08% and 1.01%. These observations suggest that vertical transmission of dengue virus may be detected in vectors at the peak of an outbreak as well as several months before an epidemic occurs in human population.

  8. Dengue haemorrhagic fever or dengue shock syndrome in children

    PubMed Central

    2015-01-01

    Introduction Dengue haemorrhagic fever and dengue shock syndrome are major causes of hospital admission and mortality in children. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of supportive treatments for dengue haemorrhagic fever or dengue shock syndrome in children? We searched: Medline, Embase, The Cochrane Library, and other important databases up to March 2014 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found nine studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: adding blood component transfusion to standard intravenous fluids; adding corticosteroids or intravenous immunoglobulin to standard intravenous fluids; and crystalloids versus colloids. PMID:25860404

  9. Evidence based community mobilization for dengue prevention in Nicaragua and Mexico (Camino Verde, the Green Way): cluster randomized controlled trial.

    PubMed

    Andersson, Neil; Nava-Aguilera, Elizabeth; Arosteguí, Jorge; Morales-Perez, Arcadio; Suazo-Laguna, Harold; Legorreta-Soberanis, José; Hernandez-Alvarez, Carlos; Fernandez-Salas, Ildefonso; Paredes-Solís, Sergio; Balmaseda, Angel; Cortés-Guzmán, Antonio Juan; Serrano de Los Santos, René; Coloma, Josefina; Ledogar, Robert J; Harris, Eva

    2015-07-08

    To test whether community mobilization adds effectiveness to conventional dengue control. Pragmatic open label parallel group cluster randomized controlled trial. Those assessing the outcomes and analyzing the data were blinded to group assignment. Centralized computerized randomization after the baseline study allocated half the sites to intervention, stratified by country, evidence of recent dengue virus infection in children aged 3-9, and vector indices. Random sample of communities in Managua, capital of Nicaragua, and three coastal regions in Guerrero State in the south of Mexico. Residents in a random sample of census enumeration areas across both countries: 75 intervention and 75 control clusters (about 140 households each) were randomized and analyzed (60 clusters in Nicaragua and 90 in Mexico), including 85,182 residents in 18,838 households. A community mobilization protocol began with community discussion of baseline results. Each intervention cluster adapted the basic intervention-chemical-free prevention of mosquito reproduction-to its own circumstances. All clusters continued the government run dengue control program. Primary outcomes per protocol were self reported cases of dengue, serological evidence of recent dengue virus infection, and conventional entomological indices (house index: households with larvae or pupae/households examined; container index: containers with larvae or pupae/containers examined; Breteau index: containers with larvae or pupae/households examined; and pupae per person: pupae found/number of residents). Per protocol secondary analysis examined the effect of Camino Verde in the context of temephos use. With cluster as the unit of analysis, serological evidence from intervention sites showed a lower risk of infection with dengue virus in children (relative risk reduction 29.5%, 95% confidence interval 3.8% to 55.3%), fewer reports of dengue illness (24.7%, 1.8% to 51.2%), fewer houses with larvae or pupae among houses visited

  10. Evidence based community mobilization for dengue prevention in Nicaragua and Mexico (Camino Verde, the Green Way): cluster randomized controlled trial

    PubMed Central

    Nava-Aguilera, Elizabeth; Arosteguí, Jorge; Morales-Perez, Arcadio; Suazo-Laguna, Harold; Legorreta-Soberanis, José; Hernandez-Alvarez, Carlos; Fernandez-Salas, Ildefonso; Paredes-Solís, Sergio; Balmaseda, Angel; Cortés-Guzmán, Antonio Juan; Serrano de los Santos, René; Coloma, Josefina; Ledogar, Robert J; Harris, Eva

    2015-01-01

    Objective To test whether community mobilization adds effectiveness to conventional dengue control. Design Pragmatic open label parallel group cluster randomized controlled trial. Those assessing the outcomes and analyzing the data were blinded to group assignment. Centralized computerized randomization after the baseline study allocated half the sites to intervention, stratified by country, evidence of recent dengue virus infection in children aged 3-9, and vector indices. Setting Random sample of communities in Managua, capital of Nicaragua, and three coastal regions in Guerrero State in the south of Mexico. Participants Residents in a random sample of census enumeration areas across both countries: 75 intervention and 75 control clusters (about 140 households each) were randomized and analyzed (60 clusters in Nicaragua and 90 in Mexico), including 85 182 residents in 18 838 households. Interventions A community mobilization protocol began with community discussion of baseline results. Each intervention cluster adapted the basic intervention—chemical-free prevention of mosquito reproduction—to its own circumstances. All clusters continued the government run dengue control program. Main outcome measures Primary outcomes per protocol were self reported cases of dengue, serological evidence of recent dengue virus infection, and conventional entomological indices (house index: households with larvae or pupae/households examined; container index: containers with larvae or pupae/containers examined; Breteau index: containers with larvae or pupae/households examined; and pupae per person: pupae found/number of residents). Per protocol secondary analysis examined the effect of Camino Verde in the context of temephos use. Results With cluster as the unit of analysis, serological evidence from intervention sites showed a lower risk of infection with dengue virus in children (relative risk reduction 29.5%, 95% confidence interval 3.8% to 55.3%), fewer reports of

  11. The Dengue Vaccine Pipeline: Implications for the Future of Dengue Control

    PubMed Central

    Schwartz, Lauren M.; Halloran, M. Elizabeth; Durbin, Anna P.; Longini, Ira M.

    2015-01-01

    Dengue has become the most rapidly expanding mosquito-borne infectious disease on the planet, surpassing malaria and infecting at least 390 million people per year. There is no effective treatment for dengue illness other than supportive care, especially for severe cases. Symptoms can be mild or life-threatening as in dengue hemorrhagic fever and dengue shock syndrome. Vector control has been only partially successful in decreasing dengue transmission. The potential use of safe and effective tetravalent dengue vaccines is an attractive addition to prevent disease or minimize the possibility of epidemics. There are currently no licensed dengue vaccines. This review summarizes the current status of all dengue vaccine candidates in clinical evaluation. Currently five candidate vaccines are in human clinical trials. One has completed two Phase III trials, two are in Phase II trials, and three are in Phase I testing. PMID:25989449

  12. Surveillance for Dengue and Dengue-Associated Neurologic Syndromes in the United States

    PubMed Central

    Waterman, Stephen H.; Margolis, Harold S.; Sejvar, James J.

    2015-01-01

    Autochthonous dengue virus transmission has occurred in the continental United States with increased frequency during the last decade; the principal vector, Aedes aegypti, has expanded its geographic distribution in the southern United States. Dengue, a potentially fatal arboviral disease, is underreported, and US clinicians encountering patients with acute febrile illness consistent with dengue are likely to not be fully familiar with dengue diagnosis and management. Recently, investigators suggested that an outbreak of dengue likely occurred in Houston during 2003 based on retrospective laboratory testing of hospitalized cases with encephalitis and aseptic meningitis. Although certain aspects of the Houston testing results and argument for local transmission are doubtful, the report highlights the importance of prospective surveillance for dengue in Aedes-infested areas of the United States, the need for clinical training on dengue and its severe manifestations, and the need for laboratory testing in domestic patients presenting with febrile neurologic illness in these regions to include dengue. PMID:25371183

  13. Is drought helping or killing dengue? Investigation of spatiotemporal relationship between dengue fever and drought

    NASA Astrophysics Data System (ADS)

    Lee, Chieh-Han; Yu, Hwa-Lung

    2015-04-01

    Dengue Fever is a vector-borne disease that is transmitted between human and mosquitos in tropical and sub-tropical regions. Previous studies have found significant relationship between the epidemic of dengue cases and climate variables, especially temperature and precipitation. Besides, the natural phenomena (e.g., drought) are considered that significantly drop the number of dengue cases by killing vector's breeding environment. However, in Kaohsiung City, Taiwan, there are evidences that the temporal pattern of dengue is correlated to drought events. Kaohsiung City experienced two main dengue outbreaks in 2002 and 2014 that both years were confirmed with serious drought. Especially in 2014, Kaohsiung City was suffered from extremely dengue outbreak in 2014 that reported the highest number of dengue cases in the history. This study constructs the spatiotemporal model of dengue incidences and index of drought events (Standardized Precipitation Index, SPI) based on the distributed lag nonlinear model (DLNM). Other meteorological measures are also included in the analysis.

  14. Surveillance for dengue and dengue-associated neurologic syndromes in the United States.

    PubMed

    Waterman, Stephen H; Margolis, Harold S; Sejvar, James J

    2015-05-01

    Autochthonous dengue virus transmission has occurred in the continental United States with increased frequency during the last decade; the principal vector, Aedes aegypti, has expanded its geographic distribution in the southern United States. Dengue, a potentially fatal arboviral disease, is underreported, and US clinicians encountering patients with acute febrile illness consistent with dengue are likely to not be fully familiar with dengue diagnosis and management. Recently, investigators suggested that an outbreak of dengue likely occurred in Houston during 2003 based on retrospective laboratory testing of hospitalized cases with encephalitis and aseptic meningitis. Although certain aspects of the Houston testing results and argument for local transmission are doubtful, the report highlights the importance of prospective surveillance for dengue in Aedes-infested areas of the United States, the need for clinical training on dengue and its severe manifestations, and the need for laboratory testing in domestic patients presenting with febrile neurologic illness in these regions to include dengue.

  15. The dengue vaccine pipeline: Implications for the future of dengue control.

    PubMed

    Schwartz, Lauren M; Halloran, M Elizabeth; Durbin, Anna P; Longini, Ira M

    2015-06-26

    Dengue has become the most rapidly expanding mosquito-borne infectious disease on the planet, surpassing malaria and infecting at least 390 million people per year. There is no effective treatment for dengue illness other than supportive care, especially for severe cases. Symptoms can be mild or life-threatening as in dengue hemorrhagic fever and dengue shock syndrome. Vector control has been only partially successful in decreasing dengue transmission. The potential use of safe and effective tetravalent dengue vaccines is an attractive addition to prevent disease or minimize the possibility of epidemics. There are currently no licensed dengue vaccines. This review summarizes the current status of all dengue vaccine candidates in clinical evaluation. Currently five candidate vaccines are in human clinical trials. One has completed two Phase III trials, two are in Phase II trials, and three are in Phase I testing.

  16. [Effects of fermented cattle dung on the growth and development of Tenebrio molitor larvae].

    PubMed

    Zeng, Xiang-Wei; Wang, Xia; Guo, Li-Yue; Zhan, Li-Jie; Bo, Wen-Jing; Li, Zhan; Wu, Guang-Lei; Jiang, Gao-Ming

    2012-07-01

    In order to make use of and industrialize the animal dung from large cattle farms, this paper explored the feasibility of using Tenebrio molitor to digest and utilize cattle dung. Cattle dung was mixed with the conventional feed (65% wheat bran, 30% corn flour, and 5% bean pulp) of T. molitor in definite proportions, and fermented with effective microorganisms (EM). The fermented products containing 60% and 80% of cattle dung (FD1 and FD2, respectively) were selected to feed T. molitor larvae, and the effects of the fermented products on the growth curve, death rate, pupation rate, and antioxidant system of the larvae were compared. Compared with CK (conventional deed), the FD1 made the developmental duration of the larvae prolonged by 10 days and the larvae's death rate upraised somewhat, but made the single larva's total food intake, average body mass, crude fat content, and ratio of unsaturated to saturated fat acids increased by 49%, 28%, 26%, and 32%, respectively (P < 0.05), and the activity of larvae's antioxidant system improved significantly, showing a remarkable adaptability of the larvae to FD1. Unlike FD1, FD2 displayed definite disadvantages in most test growth indicators, as compared with CK, indicating that T. molitor larvae had weak adaptability to FD2. Our findings suggested that using FD1 to feed the 3rd instar of T. molitor larvae would have good practical prospects in industrializing cattle dung.

  17. EVALUATION OF SUBLETHAL EFFECTS OF Ipomoea cairica LINN. EXTRACT ON LIFE HISTORY TRAITS OF DENGUE VECTORS

    PubMed Central

    ZUHARAH, Wan Fatma; AHBIRAMI, Rattanam; DIENG, Hamady; THIAGALETCHUMI, Maniam; FADZLY, Nik

    2016-01-01

    Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity) and eggs hatchability (fertility) in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors. PMID:27253746

  18. EVALUATION OF SUBLETHAL EFFECTS OF Ipomoea cairica LINN. EXTRACT ON LIFE HISTORY TRAITS OF DENGUE VECTORS.

    PubMed

    Zuharah, Wan Fatma; Ahbirami, Rattanam; Dieng, Hamady; Thiagaletchumi, Maniam; Fadzly, Nik

    2016-01-01

    Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity) and eggs hatchability (fertility) in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors.

  19. Characteristics of the spatial pattern of the dengue vector, Aedes aegypti, in Iquitos, Peru.

    PubMed

    Getis, Arthur; Morrison, Amy C; Gray, Kenneth; Scott, Thomas W

    2003-11-01

    We determine the spatial pattern of Aedes aegypti and the containers in which they develop in two neighborhoods of the Amazonian city of Iquitos, Peru. Four variables were examined: adult Ae. aegypti, pupae, containers positive for larvae or pupae, and all water-holding containers. Adults clustered strongly within houses and weakly to a distance of 30 meters beyond the household; clustering was not detected beyond 10 meters for positive containers or pupae. Over short periods of time restricted flight range and frequent blood-feeding behavior of Ae. aegypti appear to be underlying factors in the clustering patterns of human dengue infections. Permanent, consistently infested containers (key premises) were not major producers of Ae. aegypti, indicating that larvaciding strategies by themselves may be less effective than reduction of mosquito development sites by source reduction and education campaigns. We conclude that entomologic risk of human dengue infection should be assessed at the household level at frequent time intervals.

  20. Virulence Markers of Dengue Viruses

    DTIC Science & Technology

    1990-02-20

    for accurate detection of viral antigen by EIA, cells were cultured in specially treated tissue culture plates " Primaria " (Falcon product...Approximately 1 x 10 cells per well were plated into the 96 well " primaria " plates. Cell cultures were infected with several isolates of dengue-2 virus at the

  1. Drivers of Dengue Intrahost Evolution.

    PubMed

    Simon-Lorière, Etienne; Vignuzzi, Marco

    2017-09-13

    RNA viruses circulate as rapidly evolving swarms of related variants, and their evolutionary dynamics within hosts may be key to understanding virus emergence. In this issue of Cell Host & Microbe, Parameswaran et al. (2017) combine next-generation sequencing and functional studies to characterize viral populations in acute dengue infections. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Cardiac Manifestation in Dengue Fever.

    PubMed

    Arora, Mohit; Patil, Rekha S

    2016-07-01

    To study the cardiac manifestations of the dengue fever. This one year descriptive study was undertaken at KLES Dr. Prabhakar Kore Hospital and Medical Research Centre, Belgaum under the Department of Medicine. A total of 120 patients with either dengue IgM or IgM and IgG were studied. The assessment of cardiac manifestations was done based on electrocardiogram, 2D echocardiography and cardiac enzymes. Of the 120 patients, 85 (70.83%) were males and the male to female ratio was 2.4:1. The mean age of the patients was 33.02 ± 12.71 years. The commonest clinical presentation was myalgia (97.5%) followed by fever (92.5%). On clinical examination 33.33% of the patients had petecheia and only 9 patients having active bleeding manifestation at the time of presentation. A raised CK-MB and Troponin I was observed in 33.3% and 26.7% patients ECG findings revealed normal rhythm among 95% with 15.8% of them having an abnormal heart rate. Rhythm disturbance was noted in 5% of the patients with AV block being the most common (66.67%). Cardiac manifestation in the form of myocarditis was observed in 37.50% of the patients with a positive correlation with the severity of the dengue fever defined as by W.H.O. criteria. Patients with dengue fever are at high risk of developing myocarditis and rhythm disturbance and therefore require a close cardiac monitoring.

  3. Antibody response to dengue virus.

    PubMed

    Cedillo-Barrón, Leticia; García-Cordero, Julio; Bustos-Arriaga, José; León-Juárez, Moisés; Gutiérrez-Castañeda, Benito

    2014-09-01

    In this review, we discuss the current knowledge of the role of the antibody response against dengue virus and highlight novel insights into targets recognized by the human antibody response. We also discuss how the balance of pathological and protective antibody responses in the host critically influences clinical aspects of the disease. Copyright © 2014 Institut Pasteur. All rights reserved.

  4. [Efficacy of the social mobilization and the social participation in dengue control measures].

    PubMed

    Cáceres-Manrique, Flor de María; Angulo-Silva, Mary Lupe; Vesga-Gómez, Celmira

    2010-01-01

    Dengue is a public health problem. However, the efficacy of typical control programs is not well-established. The efficacy of social mobilization was assessed for its role in public empowerment in the improvement of dengue control measures. A community trial was conducted in Comuna Norte, a section of the city of Bucaramanga,Santander. Four high-incidence neighborhoods were selected--two received empowerment training and two served as controls. During 1,968 home visits, information was collected concerning knowledge and practices of dengue control, and information was provided concerning dengue and mosquito larval habitats of the vector. At local schools, dengue control information was provided for 2,455 students. The intervention included training of 155 community leaders and tracking of prevention and control activities. Findings were compared between post-intervention and controls by χ² test, with a significance level of p<0.05. At the home visits, 80.7% of respondents were female. with a mean age of 39.1 and 5.8 years schooling. In comparing the intervention neighborhoods with the controls, differences in knowledge about dengue were as follows: symptoms of bodily pain (χ²=21.0, p<0.001) and abdominal pain (χ²=5.1, p=0.024), reproduction cycle of the mosquito vector (χ²=11.5, p<0.001), knowledge of mosquitos characteristics (χ²=7.1, p=0.008). In washing practices batteries (χ²=7.2, p=0.007), spraying (χ²=7.0, p<0.008), use of bednets (χ²=49.8, p<0.001), consulting a physician (χ²=8.2, p=0.004), participate in meetings (χ²=29.6, p<0.001), prevention methods (χ²=10.4, p=0.013), willingness to lead anti-mosquito campaigns (χ²=6.8, p= 0.009) and to get help for programs (χ²=5.8, p=0.016). There was a decrease in the proportion of households with larvae from 20.0% to 15.9% in both groups. The difference in prevalence of dengue one year after initiation of the program was not significant--4.8% in the intervention group and 6.7% in control (

  5. Dengue-1 Virus Isolation during First Dengue Fever Outbreak on Easter Island, Chile

    PubMed Central

    Abarca, Katia; Ovalle, Jimena; Ferrer, Pablo; Godoy, Paula; Olea, Andrea; Aguilera, Ximena; Ferrés, Marcela

    2003-01-01

    Dengue virus was detected for the first time in Chile, in an outbreak of dengue fever on Easter Island. The virus was isolated in tissue culture and characterized by reverse transcription–polymerase chain reaction as being dengue type 1. PMID:14718094

  6. Evaluation in Rhesus Monkeys of a Bivalent Live Attenuated Dengue Vaccine Containing Types 2 and 4 Viruses.

    DTIC Science & Technology

    1984-06-01

    previous reports,(1) antibody levels of most of the vaccinated animals declined markedly on or before post vacination day 150. PR13s showed that the EM-4...V.H., Gould, D.J., Chapple, F.E., and Russell, P.K.: Dengue 2 vacine , viremia and Inmune response in rhesus monkeys. Infect. Immun. 27, 181-186, 1980. 2

  7. Dengue human infection models supporting drug development.

    PubMed

    Whitehorn, James; Van, Vinh Chau Nguyen; Simmons, Cameron P

    2014-06-15

    Dengue is a arboviral infection that represents a major global health burden. There is an unmet need for effective dengue therapeutics to reduce symptoms, duration of illness and incidence of severe complications. Here, we consider the merits of a dengue human infection model (DHIM) for drug development. A DHIM could allow experimentally controlled studies of candidate therapeutics in preselected susceptible volunteers, potentially using smaller sample sizes than trials that recruited patients with dengue in an endemic country. In addition, the DHIM would assist the conduct of intensive pharmacokinetic and basic research investigations and aid in determining optimal drug dosage. Furthermore, a DHIM could help establish proof of concept that chemoprophylaxis against dengue is feasible. The key challenge in developing the DHIM for drug development is to ensure the model reliably replicates the typical clinical and laboratory features of naturally acquired, symptomatic dengue. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.

  8. Epidemiological Scenario of Dengue in Brazil

    PubMed Central

    Fares, Rafaelle C. G.; Souza, Katia P. R.; Añez, Germán; Rios, Maria

    2015-01-01

    Dengue is the most important reemerging mosquito-borne viral disease worldwide. It is caused by any of four Dengue virus types or serotypes (DENV-1 to DENV-4) and is transmitted by mosquitoes from the genus Aedes. Ecological changes have favored the geographic expansion of the vector and, since the dengue pandemic in the Asian and Pacific regions, the infection became widely distributed worldwide, reaching Brazil in 1845. The incidence of dengue in Brazil has been frequently high, and the number of cases in the country has at some point in time represented up to 60% of the dengue reported cases worldwide. This review addresses vector distribution, dengue outbreaks, circulating serotypes and genotypes, and prevention approaches being utilized in Brazil. PMID:26413514

  9. Epidemiological Scenario of Dengue in Brazil.

    PubMed

    Fares, Rafaelle C G; Souza, Katia P R; Añez, Germán; Rios, Maria

    2015-01-01

    Dengue is the most important reemerging mosquito-borne viral disease worldwide. It is caused by any of four Dengue virus types or serotypes (DENV-1 to DENV-4) and is transmitted by mosquitoes from the genus Aedes. Ecological changes have favored the geographic expansion of the vector and, since the dengue pandemic in the Asian and Pacific regions, the infection became widely distributed worldwide, reaching Brazil in 1845. The incidence of dengue in Brazil has been frequently high, and the number of cases in the country has at some point in time represented up to 60% of the dengue reported cases worldwide. This review addresses vector distribution, dengue outbreaks, circulating serotypes and genotypes, and prevention approaches being utilized in Brazil.

  10. Hemophagocytic syndrome in classic dengue Fever.

    PubMed

    Ray, Sayantan; Kundu, Supratip; Saha, Manjari; Chakrabarti, Prantar

    2011-10-01

    A 24-year-old previously healthy girl presented with persistent fever, headache, and jaundice. Rapid-test anti-dengue virus IgM antibody was positive but anti-dengue IgG was nonreactive, which is suggestive of primary dengue infection. There was clinical deterioration during empiric antibiotic and symptomatic therapy. Bone marrow examination demonstrated the presence of hemophagocytosis. Diagnosis of dengue fever with virus-associated hemophagocytic syndrome was made according to the diagnostic criteria of the HLH 2004 protocol of the Histiocyte Society. The patient recovered with corticosteroid therapy. A review of literature revealed only a handful of case reports that showed the evidence that this syndrome is caused by dengue virus. Our patient is an interesting case of hemophagocytic syndrome associated with classic dengue fever and contributes an additional case to the existing literature on this topic. This case highlights the need for increased awareness even in infections not typically associated with hemophagocytic syndrome.

  11. Selective inhibitors of digestive enzymes from Aedes aegypti larvae identified by phage display.

    PubMed

    Soares, Tatiane Sanches; Soares Torquato, Ricardo Jose; Alves Lemos, Francisco Jose; Tanaka, Aparecida Sadae

    2013-01-01

    Dengue is a serious disease transmitted by the mosquito Aedes aegypti during blood meal feeding. It is estimated that the dengue virus is transmitted to millions of individuals each year in tropical and subtropical areas. Dengue control strategies have been based on controlling the vector, Ae. aegypti, using insecticide, but the emergence of resistance poses new challenges. The aim of this study was the identification of specific protease inhibitors of the digestive enzymes from Ae. aegypti larvae, which may serve as a prospective alternative biocontrol method. High affinity protein inhibitors were selected by all of the digestive serine proteases of the 4th instar larval midgut, and the specificity of these inhibitors was characterized. These inhibitors were obtained from a phage library displaying variants of HiTI, a trypsin inhibitor from Haematobia irritans, that are mutated in the reactive loop (P1-P4'). Based on the selected amino acid sequence pattern, seven HiTI inhibitor variants were cloned, expressed and purified. The results indicate that the HiTI variants named T6 (RGGAV) and T128 (WNEGL) were selected by larval trypsin-like (IC(50) of 1.1 nM) and chymotrypsin-like enzymes (IC(50) of 11.6 nM), respectively. The variants T23 (LLGGL) and T149 (GGVWR) inhibited both larval chymotrypsin-like (IC(50) of 4.2 nM and 29.0 nM, respectively) and elastase-like enzymes (IC(50) of 1.2 nM for both). Specific inhibitors were successfully obtained for the digestive enzymes of Ae. aegypti larvae by phage display. Our data also strongly suggest the presence of elastase-like enzymes in Ae. aegypti larvae. The HiTI variants T6 and T23 are good candidates for the development as a larvicide to control the vector.

  12. The global distribution and burden of dengue

    PubMed Central

    Bhatt, Samir; Gething, Peter W.; Brady, Oliver J.; Messina, Jane P.; Farlow, Andrew W.; Moyes, Catherine L.; Drake, John M.; Brownstein, John S.; Hoen, Anne G.; Sankoh, Osman; Myers, Monica F.; George, Dylan B.; Jaenisch, Thomas; Wint, G.R. William; Simmons, Cameron P.; Scott, Thomas W.; Farrar, Jeremy J.; Hay, Simon I.

    2013-01-01

    Dengue is a systemic viral infection transmitted between humans by Aedes mosquitoes1. For some patients dengue is a life-threatening illness2. There are currently no licensed vaccines or specific therapeutics, and substantial vector control efforts have not stopped its rapid emergence and global spread3. The contemporary worldwide distribution of the risk of dengue virus infection4 and its public health burden are poorly known2,5. Here we undertake an exhaustive assembly of known records of dengue occurrence worldwide, and use a formal modelling framework to map the global distribution of dengue risk. We then pair the resulting risk map with detailed longitudinal information from dengue cohort studies and population surfaces to infer the public health burden of dengue in 2010. We predict dengue to be ubiquitous throughout the tropics, with local spatial variations in risk influenced strongly by rainfall, temperature and the degree of urbanisation. Using cartographic approaches, we estimate there to be 390 million (95 percent credible interval 284-528) dengue infections per year, of which 96 million (67-136) manifest apparently (any level of clinical or sub-clinical severity). This infection total is more than three times the dengue burden estimate of the World Health Organization2. Stratification of our estimates by country allows comparison with national dengue reporting, after taking into account the probability of an apparent infection being formally reported. The most notable differences are discussed. These new risk maps and infection estimates provide novel insights into the global, regional and national public health burden imposed by dengue. We anticipate that they will provide a starting point for a wider discussion about the global impact of this disease and will help guide improvements in disease control strategies using vaccine, drug and vector control methods and in their economic evaluation. [285] PMID:23563266

  13. Dengue associated choroiditis: a rare entity.

    PubMed

    Yadav, Harshali Manish; Dutta Majumder, Parthopratim; Biswas, Jyotirmay

    2017-12-01

    We report a case of choroiditis during dengue fever. A 35-year-old female presented with blurring of vision during dengue fever. Her fundus examination revealed yellow deep choroidal lesions at right macula, multiple small, yellowish subretinal macular dots along papillomacular bundle, and hyperemic disc. There was a small retinal hemorrhage at temporal margin of disc. The left eye had similar small discrete lesion superonasal and inferotemporal to macula. We report a hitherto undescribed case of choroiditis in a dengue patient.

  14. Dengue-associated acute kidney injury

    PubMed Central

    Oliveira, João Fernando Picollo; Burdmann, Emmanuel A.

    2015-01-01

    Dengue is presently the most relevant viral infection transmitted by a mosquito bite that represents a major threat to public health worldwide. Acute kidney injury (AKI) is a serious and potentially lethal complication of this disease, and the actual incidence is unknown. In this review, we will assess the most relevant epidemiological and clinical data regarding dengue and the available evidence on the frequency, etiopathogenesis, outcomes and treatment of dengue-associated AKI. PMID:26613023

  15. Dengue fever: a primer for the otolaryngologist.

    PubMed

    Arnaoutakis, Demetri; Padhya, Tapan A

    2013-07-01

    It has been estimated that more than 50 million cases of dengue occur worldwide each year, mostly in the tropics. In light of recent cases appearing in central and southern Florida, dengue has reemerged as a public health issue in the United States with respect to infection control and prevention. We review the course of dengue infection and its clinical presentation from the perspective of the practicing otolaryngologist, and we outline tactics for prevention and management.

  16. Identification of Carboxylesterase Genes Implicated in Temephos Resistance in the Dengue Vector Aedes aegypti

    PubMed Central

    Poupardin, Rodolphe; Srisukontarat, Wannaporn; Yunta, Cristina; Ranson, Hilary

    2014-01-01

    Background Thailand is currently experiencing one of its worst dengue outbreaks in decades. As in most countries where this disease is endemic, dengue control in Thailand is largely reliant on the use of insecticides targeting both immature and adult stages of the Aedes mosquito, with the organophosphate insecticide, temephos, being the insecticide of choice for attacking the mosquito larvae. Resistance to temephos was first detected in Aedes aegypti larvae in Thailand approximately 25 years ago but the mechanism responsible for this resistance has not been determined. Principal Findings Bioassays on Ae. aegypti larvae from Thailand detected temephos resistance ratios ranging from 3.5 fold in Chiang Mai to nearly 10 fold in Nakhon Sawan (NS) province. Synergist and biochemical assays suggested a role for increased carboxylesterase (CCE) activities in conferring temephos resistance in the NS population and microarray analysis revealed that the CCE gene, CCEae3a, was upregulated more than 60 fold in the NS population compared to the susceptible population. Upregulation of CCEae3a was shown to be partially due to gene duplication. Another CCE gene, CCEae6a, was also highly regulated in both comparisons. Sequencing and in silico structure prediction of CCEae3a showed that several amino acid polymorphisms in the NS population may also play a role in the increased resistance phenotype. Significance Carboxylesterases have previously been implicated in conferring temephos resistance in Ae aegypti but the specific member(s) of this family responsible for this phenotype have not been identified. The identification of a strong candidate is an important step in the development of new molecular diagnostic tools for management of temephos resistant populations and thus improved control of dengue. PMID:24651719

  17. Dengue blood analysis by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Rehman, A.; Anwar, S.; Firdous, S.; Ahmed, M.; Rasheed, R.; Nawaz, M.

    2012-06-01

    In this work Raman spectra of normal and dengue infected serum and whole blood were analyzed. In normal whole blood and serum characteristic peaks were observed when excited at 442 and 532 nm. In dengue whole blood and serum all peaks found to be blue shifted with reduced Raman intensity. Dengue whole blood and serum shows two peaks at 1614 and 1750 cm-1 which are due to presence of Immunoglobulin antibodies IgG and IgM. Whole study provides a route of information for diagnosis of dengue viral infection.

  18. Dengue Fever: Causes, Complications, and Vaccine Strategies

    PubMed Central

    Khanna, Ira

    2016-01-01

    Dengue is a highly endemic infectious disease of the tropical countries and is rapidly becoming a global burden. It is caused by any of the 4 serotypes of dengue virus and is transmitted within humans through female Aedes mosquitoes. Dengue disease varies from mild fever to severe conditions of dengue hemorrhagic fever and shock syndrome. Globalization, increased air travel, and unplanned urbanization have led to increase in the rate of infection and helped dengue to expand its geographic and demographic distribution. Dengue vaccine development has been a challenging task due to the existence of four antigenically distinct dengue virus serotypes, each capable of eliciting cross-reactive and disease-enhancing antibody response against the remaining three serotypes. Recently, Sanofi Pasteur's chimeric live-attenuated dengue vaccine candidate has been approved in Mexico, Brazil, and Philippines for usage in adults between 9 and 45 years of age. The impact of its limited application to the public health system needs to be evaluated. Simultaneously, the restricted application of this vaccine candidate warrants continued efforts in developing a dengue vaccine candidate which is additionally efficacious for infants and naïve individuals. In this context, alternative strategies of developing a designed vaccine candidate which does not allow production of enhancing antibodies should be explored, as it may expand the umbrella of efficacy to include infants and naïve individuals. PMID:27525287

  19. Human Immune Response to Dengue Infections.

    DTIC Science & Technology

    1991-06-30

    DTIC AD-A240 717 AD ____ HUMAN IMMUNE RESPONSE TO DENGUE INFECTIONS ANNUAL REPORT FRANCIS A. ENNIS JUNE 30, 1991 Supported by U.S. ARMY MEDICAL...Immune Response to Dengue Infections DAMDI7-86-C-6208 6. AUTHOR(S) 61102A 1 3M161102BS13 AA Francis A. Ennis WUDA3 12059 7. PERFORMING ORGANIZATION...of NS3, respectively. We also established 16 dengue virus-specific CD8+ CD4_ T cell clones. The clone #/2.8 recognize dengue virus types 2 and 4, and

  20. Use of Saliva for Early Dengue Diagnosis

    PubMed Central

    Ng, Lee-Ching

    2011-01-01

    Background The necessity of a venous blood collection in all dengue diagnostic assays and the high cost of tests that are available for testing during the viraemic period hinder early detection of dengue cases and thus could delay cluster management. This study reports the utility of saliva in an assay that detects dengue virus (DENV)–specific immunoglobulin A (Ig A) early in the phase of a dengue infection. Methods and Findings Using an antigen capture anti-DENV IgA (ACA) ELISA technique, we tested saliva samples collected from dengue-confirmed patients. The sensitivity within 3 days from fever onset was over 36% in primary dengue infections. The performance is markedly better in secondary infections, with 100% sensitivity reported in saliva samples from day 1 after fever onset. Serum and salivary IgA levels showed good correlation (Pearson's r = 0.69, p<0.001). Specificity was found to be 97%. Conclusion Our findings suggest that this technique would be very useful in dengue endemic regions, where the majority of dengue cases are secondary. The ACA-ELISA is easy to perform, cost effective, and especially useful in laboratories without sophisticated equipment. Our findings established the usefulness and reliability of saliva for early dengue diagnosis. PMID:21572982

  1. Dengue Fever: Causes, Complications, and Vaccine Strategies.

    PubMed

    Khetarpal, Niyati; Khanna, Ira

    2016-01-01

    Dengue is a highly endemic infectious disease of the tropical countries and is rapidly becoming a global burden. It is caused by any of the 4 serotypes of dengue virus and is transmitted within humans through female Aedes mosquitoes. Dengue disease varies from mild fever to severe conditions of dengue hemorrhagic fever and shock syndrome. Globalization, increased air travel, and unplanned urbanization have led to increase in the rate of infection and helped dengue to expand its geographic and demographic distribution. Dengue vaccine development has been a challenging task due to the existence of four antigenically distinct dengue virus serotypes, each capable of eliciting cross-reactive and disease-enhancing antibody response against the remaining three serotypes. Recently, Sanofi Pasteur's chimeric live-attenuated dengue vaccine candidate has been approved in Mexico, Brazil, and Philippines for usage in adults between 9 and 45 years of age. The impact of its limited application to the public health system needs to be evaluated. Simultaneously, the restricted application of this vaccine candidate warrants continued efforts in developing a dengue vaccine candidate which is additionally efficacious for infants and naïve individuals. In this context, alternative strategies of developing a designed vaccine candidate which does not allow production of enhancing antibodies should be explored, as it may expand the umbrella of efficacy to include infants and naïve individuals.

  2. Economic Cost of Dengue in Puerto Rico

    PubMed Central

    Halasa, Yara A.; Shepard, Donald S.; Zeng, Wu

    2012-01-01

    Dengue, endemic in Puerto Rico, reached a record high in 2010. To inform policy makers, we derived annual economic cost. We assessed direct and indirect costs of hospitalized and ambulatory dengue illness in 2010 dollars through surveillance data and interviews with 100 laboratory-confirmed dengue patients treated in 2008–2010. We corrected for underreporting by using setting-specific expansion factors. Work absenteeism because of a dengue episode exceeded the absenteeism for an episode of influenza or acute otitis media. From 2002 to 2010, the aggregate annual cost of dengue illness averaged $38.7 million, of which 70% was for adults (age 15+ years). Hospitalized patients accounted for 63% of the cost of dengue illness, and fatal cases represented an additional 17%. Households funded 48% of dengue illness cost, the government funded 24%, insurance funded 22%, and employers funded 7%. Including dengue surveillance and vector control activities, the overall annual cost of dengue was $46.45 million ($12.47 per capita). PMID:22556069

  3. Culturing larvae of marine invertebrates.

    PubMed

    Strathmann, Richard R

    2014-01-01

    Larvae of marine invertebrates cultured in the laboratory experience conditions that they do not encounter in nature, but development and survival to metamorphic competence can be obtained in such cultures. This protocol emphasizes simple methods suitable for a wide variety of larvae. Culturing larvae requires seawater of adequate quality and temperature within the tolerated range. Beyond that, feeding larvae require appropriate food, but a few kinds of algae and animals are sufficient as food for diverse larvae. Nontoxic materials include glass, many plastics, hot-melt glue, and some solvents, once evaporated. Cleaners that do not leave toxic residues after rinsing include dilute hydrochloric or acetic acid, sodium hypochlorite (commercial bleach), and ethanol. Materials that can leave toxic residues, such as formaldehyde, glutaraldehyde, detergents, and hand lotions, should be avoided, especially with batch cultures that lack continuously renewed water. Reverse filtration can be used to change water gently at varying frequencies, depending on temperature and the kinds of food that are provided. Bacterial growth can be limited by antibiotics, but antibiotics are often unnecessary. Survival and growth are increased by low concentrations of larvae and stirring of large or dense cultures. One method of stirring large numbers of containers is a rack of motor-driven paddles. Most of the methods and materials are inexpensive and portable. If necessary, a room within a few hours of the sea could be temporarily equipped for larval culture.

  4. PirAB toxin from Photorhabdus asymbiotica as a larvicide against dengue vectors.

    PubMed

    Ahantarig, Arunee; Chantawat, Nantarat; Waterfield, Nicholas R; ffrench-Constant, Richard; Kittayapong, Pattamaporn

    2009-07-01

    We have evaluated Photorhabdus insect-related protein (Pir) from Photorhabdus asymbiotica against dengue vectors. PirAB shows larvicidal activity against both Aedes aegypti and Aedes albopictus larvae but did not affect the Mesocyclops thermocyclopoides predator. PirAB expressed the strongest toxicity compared to PirA, PirB, or the mixture of PirA plus PirB. Whether the presence of an enterobacterial repetitive intergenic consensus sequence in PirAB, but not in PirA, PirB, or the mixture of PirA plus PirB, has any impact on biological control efficacy needs further investigation.

  5. Anti-dengue efficacy of bioactive andrographolide from Andrographis paniculata (Lamiales: Acanthaceae) against the primary dengue vector Aedes aegypti (Diptera: Culicidae).

    PubMed

    Edwin, Edward-Sam; Vasantha-Srinivasan, Prabhakaran; Senthil-Nathan, Sengottayan; Thanigaivel, Annamalai; Ponsankar, Athirstam; Pradeepa, Venkatraman; Selin-Rani, Selvaraj; Kalaivani, Kandaswamy; Hunter, Wayne B; Abdel-Megeed, Ahmed; Duraipandiyan, Veeramuthu; Al-Dhabi, Naif Abdullah

    2016-11-01

    The current study investigated the toxic effect of the leaf extract compound andrographolide from Andrographis paniculata (Burm.f) against the dengue vector Ae. aegypti. GC-MS analysis revealed that andrographolide was recognized as the major chemical constituent with the prominent peak area compared with other compounds. All isolated toxic compounds were purified and confirmed through RP-HPLC against chemical standards. The larvicidal assays established at 25ppm of bioactive compound against the treated instars of Ae. Aegypti showed prominent mortality compared to other treated concentrations. The percent mortality of larvae was directly proportional to concentration. The lethal concentration (LC50) was observed at 12ppm treatment concentration. The bioactive andrographolide considerably reduced the detoxifying enzyme regulations of α- and β- carboxylesterases. In contrast, the levels of GST and CYP450 significantly increase in a dose dependent manner. The andrographolide also showed strong oviposition deterrence effects at the sub-lethal dose of 12ppm. Similarly, the mean number of eggs were also significantly reduced in a dose dependent manner. At the concentration of 12ppm the effective percentage of repellency was greater than 90% with a protection time of 15-210min, compared with control. The histopathology study displayed that larvae treated with bioactive andrographolide had cytopathic effects in the midgut epithelium compared with the control. The present study established that bioactive andrographolide served as a potential useful for dengue vector management. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Optimal Lead Time for Dengue Forecast

    PubMed Central

    Hii, Yien Ling; Rocklöv, Joacim; Wall, Stig; Ng, Lee Ching; Tang, Choon Siang; Ng, Nawi

    2012-01-01

    Background A dengue early warning system aims to prevent a dengue outbreak by providing an accurate prediction of a rise in dengue cases and sufficient time to allow timely decisions and preventive measures to be taken by local authorities. This study seeks to identify the optimal lead time for warning of dengue cases in Singapore given the duration required by a local authority to curb an outbreak. Methodology and Findings We developed a Poisson regression model to analyze relative risks of dengue cases as functions of weekly mean temperature and cumulative rainfall with lag times of 1–5 months using spline functions. We examined the duration of vector control and cluster management in dengue clusters > = 10 cases from 2000 to 2010 and used the information as an indicative window of the time required to mitigate an outbreak. Finally, we assessed the gap between forecast and successful control to determine the optimal timing for issuing an early warning in the study area. Our findings show that increasing weekly mean temperature and cumulative rainfall precede risks of increasing dengue cases by 4–20 and 8–20 weeks, respectively. These lag times provided a forecast window of 1–5 months based on the observed weather data. Based on previous vector control operations, the time needed to curb dengue outbreaks ranged from 1–3 months with a median duration of 2 months. Thus, a dengue early warning forecast given 3 months ahead of the onset of a probable epidemic would give local authorities sufficient time to mitigate an outbreak. Conclusions Optimal timing of a dengue forecast increases the functional value of an early warning system and enhances cost-effectiveness of vector control operations in response to forecasted risks. We emphasize the importance of considering the forecast-mitigation gaps in respective study areas when developing a dengue forecasting model. PMID:23110242

  7. Dengue Fever (DF) in Pakistan

    PubMed Central

    2011-01-01

    Dengue is a widespread mosquito-borne infection in human beings, which in recent years has become a major international public health concern. Symptomatic dengue virus infections can present with a wide range of clinical manifestations, from a mild febrile illness to a life-threatening shock syndrome. Both viral and host factors are thought to contribute to the manifestations of disease in each infected. It is important to understand its burden on health care, morbidity and mortality. Early diagnosis and suspicion of DF in primary care might reduce the complications if handled properly. We must understand the depth of the problem in terms of its transmission, clinical presentation, diagnosis, management and prevention. PMID:21349169

  8. Laboratory surveillance of dengue in Argentina, 1995-2001.

    PubMed

    Avilés, Gabriela; Paz, Maria Valeria; Rangeon, Griselda; Ranaivoarisoa, Marie Y; Verzeri, Nora; Roginski, Sandra; Baroni, Pablo; Enria, Delia

    2003-06-01

    Local transmission of dengue fever virus in Argentina is increased by the presence of Aedes aegypti mosquitoes and dengue outbreaks in neighboring countries. From 1995 to 2001, a laboratory-based active surveillance program detected 922 dengue cases. Indigenous transmission involving dengue-1 and -2 serotypes was confirmed only in subtropical areas in northern Argentina.

  9. Urban Epidemic of Dengue Virus Serotype 3 Infection, Senegal, 2009

    PubMed Central

    Faye, Ousmane; Ba, Yamar; Faye, Oumar; Talla, Cheikh; Diallo, Diawo; Chen, Rubing; Mondo, Mireille; Ba, Rouguiétou; Macondo, Edgard; Siby, Tidiane; Weaver, Scott C.; Diallo, Mawlouth

    2014-01-01

    An urban epidemic of dengue in Senegal during 2009 affected 196 persons and included 5 cases of dengue hemorrhagic fever and 1 fatal case of dengue shock syndrome. Dengue virus serotype 3 was identified from all patients, and Aedes aegypti mosquitoes were identified as the primary vector of the virus. PMID:24572297

  10. Urban epidemic of dengue virus serotype 3 infection, Senegal, 2009.

    PubMed

    Faye, Ousmane; Ba, Yamar; Faye, Oumar; Talla, Cheikh; Diallo, Diawo; Chen, Rubing; Mondo, Mireille; Ba, Rouguiétou; Macondo, Edgard; Siby, Tidiane; Weaver, Scott C; Diallo, Mawlouth; Sall, Amadou Alpha

    2014-03-01

    An urban epidemic of dengue in Senegal during 2009 affected 196 persons and included 5 cases of dengue hemorrhagic fever and 1 fatal case of dengue shock syndrome. Dengue virus serotype 3 was identified from all patients, and Aedes aegypti mosquitoes were identified as the primary vector of the virus.

  11. Implications of Dengue Outbreaks for Blood Supply, Australia

    PubMed Central

    Seed, Clive R.; Fryk, Jesse J.; Hyland, Catherine A.; Ritchie, Scott A.; Taylor, Carmel T.; Van Der Merwe, Kathryn L.; Flower, Robert L.P.; McBride, William J.H.

    2013-01-01

    Dengue outbreaks have increased in size and frequency in Australia, and transfusion-transmitted dengue poses a risk to transfusion safety. Using whole blood samples collected during the large 2008–2009 dengue epidemic, we estimated the risk for a dengue-infectious blood donation as ≈1 in 7,146 (range 2,218–50,021). PMID:23648012

  12. Oxidative damage in dengue fever.

    PubMed

    Seet, Raymond C S; Lee, Chung-Yung J; Lim, Erle C H; Quek, Amy M L; Yeo, Leonard L L; Huang, Shan-Hong; Halliwell, Barry

    2009-08-15

    Oxidative stress may be important in the pathogenesis of dengue infection. Using accurate markers of oxidative damage, we assessed the extent of oxidative damage in dengue patients. The levels of hydroxyeicosatetraenoic acid products (HETEs), F(2)-isoprostanes (F(2)-IsoPs), and cholesterol oxidation products (COPs) were measured in 28 adult dengue patients and 28 age-matched study controls during the febrile, defervescent, and convalescent stages of infection. We compared the absolute and the percentage change in these markers in relation to key clinical parameters and inflammatory markers. The levels of total HETEs and total HETEs/arachidonate, total F(2)-IsoPs/arachidonate, and COPs/cholesterol were higher during the febrile compared to the convalescent level. Total HETEs correlated positively with admission systolic blood pressure (r=0.52, p<0.05), whereas an inverse relationship was found between 7beta-hydroxycholesterol and systolic and diastolic blood pressure (r=-0.61 and -0.59, respectively, p<0.01). The urinary F(2)-IsoP level was higher in urine during the febrile stage compared to the convalescent level. Despite lower total cholesterol levels during the febrile stage compared to convalescent levels, a higher percentage of cholesterol was found as COPs (7beta-, 24-, and 27-hydroxycholesterol). The levels of platelet-activating factor-acetylhydrolase activity, vascular cellular adhesion molecule-1, tumor necrosis factor-alpha, and high-sensitivity C-reactive protein were higher during the febrile stage compared to their convalescent levels (p<0.01). Markers of oxidative damage are altered during the various stages of dengue infection.

  13. Spatial Distribution of the Risk of Dengue and the Entomological Indicators in Sumaré, State of São Paulo, Brazil

    PubMed Central

    Barbosa, Gerson Laurindo; Donalísio, Maria Rita; Stephan, Celso; Lourenço, Roberto Wagner; Andrade, Valmir Roberto; Arduino, Marylene de Brito; de Lima, Virgilia Luna Castor

    2014-01-01

    Dengue fever is a major public health problem worldwide, caused by any of four virus (DENV-1, DENV-2, DENV-3 and DENV-4; Flaviviridae: Flavivirus), transmitted by Aedes aegypti mosquito. Reducing the levels of infestation by A. aegypti is one of the few current strategies to control dengue fever. Entomological indicators are used by dengue national control program to measure the infestation of A. aegypti, but little is known about predictive power of these indicators to measure dengue risk. In this spatial case-control study, we analyzed the spatial distribution of the risk of dengue and the influence of entomological indicators of A. aegypti in its egg, larva-pupa and adult stages occurring in a mid-size city in the state of São Paulo. The dengue cases were those confirmed by the city's epidemiological surveillance system and the controls were obtained through random selection of points within the perimeter of the inhabited area. The values of the entomological indicators were extrapolated for the entire study area through the geostatistical ordinary kriging technique. For each case and control, the respective indicator values were obtained, according with its geographical coordinates and analyzed by using a generalized additive model. Dengue incidence demonstrated a seasonal behavior, as well as the entomological indicators of all mosquito's evolutionary stages. The infestation did not present a significant variation in intensity and was not a limiting or determining factor of the occurrence of cases in the municipality. The risk maps of the disease from crude and adjusted generalized additive models did not present differences, suggesting that areas with the highest values of entomological indicators were not associated with the incidence of dengue. The inclusion of other variables in the generalized additive models may reveal the modulatory effect for the risk of the disease, which is not found in this study. PMID:24831806

  14. Spatial distribution of the risk of dengue and the entomological indicators in Sumaré, state of São Paulo, Brazil.

    PubMed

    Barbosa, Gerson Laurindo; Donalísio, Maria Rita; Stephan, Celso; Lourenço, Roberto Wagner; Andrade, Valmir Roberto; Arduino, Marylene de Brito; de Lima, Virgilia Luna Castor

    2014-05-01

    Dengue fever is a major public health problem worldwide, caused by any of four virus (DENV-1, DENV-2, DENV-3 and DENV-4; Flaviviridae: Flavivirus), transmitted by Aedes aegypti mosquito. Reducing the levels of infestation by A. aegypti is one of the few current strategies to control dengue fever. Entomological indicators are used by dengue national control program to measure the infestation of A. aegypti, but little is known about predictive power of these indicators to measure dengue risk. In this spatial case-control study, we analyzed the spatial distribution of the risk of dengue and the influence of entomological indicators of A. aegypti in its egg, larva-pupa and adult stages occurring in a mid-size city in the state of São Paulo. The dengue cases were those confirmed by the city's epidemiological surveillance system and the controls were obtained through random selection of points within the perimeter of the inhabited area. The values of the entomological indicators were extrapolated for the entire study area through the geostatistical ordinary kriging technique. For each case and control, the respective indicator values were obtained, according with its geographical coordinates and analyzed by using a generalized additive model. Dengue incidence demonstrated a seasonal behavior, as well as the entomological indicators of all mosquito's evolutionary stages. The infestation did not present a significant variation in intensity and was not a limiting or determining factor of the occurrence of cases in the municipality. The risk maps of the disease from crude and adjusted generalized additive models did not present differences, suggesting that areas with the highest values of entomological indicators were not associated with the incidence of dengue. The inclusion of other variables in the generalized additive models may reveal the modulatory effect for the risk of the disease, which is not found in this study.

  15. Recent Advances in Dengue: Relevance to Puerto Rico.

    PubMed

    Noyd, David H; Sharp, Tyler M

    2015-06-01

    Dengue represents an increasingly important public health challenge in Puerto Rico, with recent epidemics in 2007, 2010, and 2012-2013. Although recent advances in dengue vaccine development offer hope for primary prevention, the role of health professionals in the diagnosis and management of dengue patients is paramount. Case definitions for dengue, dengue with warning signs, and severe dengue provide a framework to guide clinical decision-making. Furthermore, the differentiation between dengue and other acute febrile illnesses, such as leptospirosis and chikungunya, is necessary for the appropriate diagnosis and management of cases. An understanding of dengue epidemiology and surveillance in Puerto Rico provides context for clinicians in epidemic and non-epidemic periods. This review aims to improve health professionals' ability to diagnose dengue, and as highlight the relevance of recent advances in dengue prevention and management in Puerto Rico.

  16. Recent Advances in Dengue: Relevance to Puerto Rico

    PubMed Central

    Noyd, David H.; Sharp, Tyler M.

    2015-01-01

    Dengue represents an increasingly important public health challenge in Puerto Rico, with recent epidemics in 2007, 2010, and 2012–2013. Although recent advances in dengue vaccine development offer hope for primary prevention, the role of health professionals in the diagnosis and management of dengue patients is paramount. Case definitions for dengue, dengue with warning signs, and severe dengue provide a framework to guide clinical decision-making. Furthermore, the differentiation between dengue and other acute febrile illnesses, such as leptospirosis and chikungunya, is necessary for the appropriate diagnosis and management of cases. An understanding of dengue epidemiology and surveillance in Puerto Rico provides context for clinicians in epidemic and non-epidemic periods. This review aims to improve health professionals’ ability to diagnose dengue, and as highlight the relevance of recent advances in dengue prevention and management in Puerto Rico. PMID:26061055

  17. Social justice, climate change, and dengue.

    PubMed

    Chang, Aileen Y; Fuller, Douglas O; Carrasquillo, Olveen; Beier, John C

    2014-06-14

    Climate change should be viewed fundamentally as an issue of global justice. Understanding the complex interplay of climatic and socioeconomic trends is imperative to protect human health and lessen the burden of diseases such as dengue fever. Dengue fever is rapidly expanding globally. Temperature, rainfall, and frequency of natural disasters, as well as non-climatic trends involving population growth and migration, urbanization, and international trade and travel, are expected to increase the prevalence of mosquito breeding sites, mosquito survival, the speed of mosquito reproduction, the speed of viral incubation, the distribution of dengue virus and its vectors, human migration patterns towards urban areas, and displacement after natural disasters. The burden of dengue disproportionately affects the poor due to increased environmental risk and decreased health care. Mobilization of social institutions is needed to improve the structural inequalities of poverty that predispose the poor to increased dengue fever infection and worse outcomes. This paper reviews the link between dengue and climatic factors as a starting point to developing a comprehensive understanding of how climate change affects dengue risk and how institutions can address the issues of social justice and dengue outbreaks that increasingly affect vulnerable urban populations.

  18. Dengue and Chikungunya Vector Control Pocket Guide

    USDA-ARS?s Scientific Manuscript database

    This technical guide consolidates information and procedures for surveillance and control of mosquitoes that transmit dengue and chikungunya viruses. The guide focuses on mosquitoes that transmit dengue but also makes reference to chikungunya and yellow fever because the pathogens that cause these ...

  19. Development of Dengue Infection Severity Score

    PubMed Central

    Pongpan, Surangrat; Tawichasri, Chamaiporn; Namwongprom, Sirianong

    2013-01-01

    Objectives. To develop a simple scoring system to predict dengue infection severity based on patient characteristics and routine clinical profiles. Methods. Retrospective data of children with dengue infection from 3 general hospitals in Thailand were reviewed. Dengue infection was categorized into 3 severity levels: dengue infection (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). Coefficients of significant predictors of disease severity under ordinal regression analysis were transformed into item scores. Total scores were used to classify patients into 3 severity levels. Results. Significant clinical predictors of dengue infection severity were age >6 years, hepatomegaly, hematocrit ≥40%, systolic pressure <90 mmHg, white cell count >5000 /μL, and platelet ≤50000 /μL. The derived total scores, which ranged from 0 to 18, classified patients into 3 severity levels: DF (scores <2.5, n = 451, 58.1%), DHF (scores 2.5–11.5, n = 276, 35.5%), and DSS (scores >11.5, n = 50, 6.4%). The derived score correctly classified patients into their original severity levels in 60.7%. An under-estimation of 25.7% and an over-estimation of 13.5% were clinically acceptable. Conclusions. The derived dengue infection severity score classified patients into DF, DHF, or DSS, correctly into their original severity levels. Validation of the score should be reconfirmed before application of routine practice. PMID:24324896

  20. Hepatic Involvement in Dengue Fever in Children

    PubMed Central

    Jagadishkumar, Kalenahalli; Jain, Puja; Manjunath, Vaddambal G.; Umesh, Lingappa

    2012-01-01

    Objective Hepatic dysfunction is common in dengue infection and the degree of liver dysfunction in children varies from mild injury with elevation of transaminases to severe injury with jaundice. This study was undertaken to assess the spectrum of hepatic involvement in dengue infection. Methods 110 children with serologically positive dengue fever aged between 2 months - 14 years were studied for their hepatic functions both clinically and biochemically after excluding malaria, enteric fever, Hepatitis A and Hepatitis B with relevant investigations. Findings All cases were grouped into DF (Dengue fever), DHF (Dengue hemorrhagic fever) and DSS (Dengue shock syndrome) according to WHO criteria. The spectrum of hepatic manifestations included hepatomegaly (79%), hepatic tenderness (56%), jaundice (4.5%), raised levels of aspartate transaminase (AST)(93%), alanine transaminase (ALT)(78%), alkaline phosphatase (AP) (57%), prolonged prothrombin time (PT) (20%), reduced levels of serum albumin (66%) and abnormal abdomen ultrasound (65%). Conclusion Hepatic dysfunction was observed more in DHF and DSS group compared to DF group. About 17.27% of children had >10 fold increase in the liver enzymes. There was no correlation between the degree of hepatic enlargement or hepatic tenderness with the abnormalities of liver functions. Any child with fever, jaundice and tender hepatomegaly in geographical areas where dengue is endemic, the diagnosis of dengue infection should be strongly considered. PMID:23056891

  1. Hepatic involvement in dengue Fever in children.

    PubMed

    Jagadishkumar, Kalenahalli; Jain, Puja; Manjunath, Vaddambal G; Umesh, Lingappa

    2012-06-01

    Hepatic dysfunction is common in dengue infection and the degree of liver dysfunction in children varies from mild injury with elevation of transaminases to severe injury with jaundice. This study was undertaken to assess the spectrum of hepatic involvement in dengue infection. 110 children with serologically positive dengue fever aged between 2 months - 14 years were studied for their hepatic functions both clinically and biochemically after excluding malaria, enteric fever, Hepatitis A and Hepatitis B with relevant investigations. All cases were grouped into DF (Dengue fever), DHF (Dengue hemorrhagic fever) and DSS (Dengue shock syndrome) according to WHO criteria. The spectrum of hepatic manifestations included hepatomegaly (79%), hepatic tenderness (56%), jaundice (4.5%), raised levels of aspartate transaminase (AST)(93%), alanine transaminase (ALT)(78%), alkaline phosphatase (AP) (57%), prolonged prothrombin time (PT) (20%), reduced levels of serum albumin (66%) and abnormal abdomen ultrasound (65%). Hepatic dysfunction was observed more in DHF and DSS group compared to DF group. About 17.27% of children had >10 fold increase in the liver enzymes. There was no correlation between the degree of hepatic enlargement or hepatic tenderness with the abnormalities of liver functions. Any child with fever, jaundice and tender hepatomegaly in geographical areas where dengue is endemic, the diagnosis of dengue infection should be strongly considered.

  2. The Risk of Dengue Virus Transmission in Dar es Salaam, Tanzania during an Epidemic Period of 2014

    PubMed Central

    Mboera, Leonard E. G.; Mweya, Clement N.; Rumisha, Susan F.; Tungu, Patrick K.; Stanley, Grades; Makange, Mariam R.; Misinzo, Gerald; De Nardo, Pasquale; Vairo, Francesco; Oriyo, Ndekya M.

    2016-01-01

    Background In 2010, 2012, 2013 and 2014 dengue outbreaks have been reported in Dar es Salaam, Tanzania. However, there is no comprehensive data on the risk of transmission of dengue in the country. The objective of this study was to assess the risk of transmission of dengue in Dar es Salaam during the 2014 epidemic. Methodology/Principal Findings This cross-sectional study was conducted in Dar es Salaam, Tanzania during the dengue outbreak of 2014. The study involved Ilala, Kinondoni and Temeke districts. Adult mosquitoes were collected using carbon dioxide-propane powered Mosquito Magnet Liberty Plus traps. In each household compound, water-holding containers were examined for mosquito larvae and pupae. Dengue virus infection of mosquitoes was determined using real-time reverse transcription polymerase chain reaction (qRT-PCR). Partial amplification and sequencing of dengue virus genome in infected mosquitoes was performed. A total of 1,000 adult mosquitoes were collected. Over half (59.9%) of the adult mosquitoes were collected in Kinondoni. Aedes aegypti accounted for 17.2% of the mosquitoes of which 90.6% were from Kinondoni. Of a total of 796 houses inspected, 38.3% had water-holding containers in their premises. Kinondoni had the largest proportion of water-holding containers (57.7%), followed by Temeke (31.4%) and Ilala (23.4%). The most common breeding containers for the Aedes mosquitoes were discarded plastic containers and tires. High Aedes infestation indices were observed for all districts and sites, with a house index of 18.1% in Ilala, 25.5% in Temeke and 35.3% in Kinondoni. The respective container indices were 77.4%, 65.2% and 80.2%. Of the reared larvae and pupae, 5,250 adult mosquitoes emerged, of which 61.9% were Ae. aegypti. Overall, 27 (8.18) of the 330 pools of Ae. aegypti were positive for dengue virus. On average, the overall maximum likelihood estimate (MLE) indicates pooled infection rate of 8.49 per 1,000 mosquitoes (95%CI = 5.72–12

  3. Novel, Meso-Substituted Cationic Porphyrin Molecule for Photo-Mediated Larval Control of the Dengue Vector Aedes aegypti

    PubMed Central

    Lucantoni, Leonardo; Magaraggia, Michela; Lupidi, Giulio; Ouedraogo, Robert Kossivi; Coppellotti, Olimpia; Esposito, Fulvio; Fabris, Clara; Jori, Giulio; Habluetzel, Annette

    2011-01-01

    Background Control of the mosquito vector population is the most effective strategy currently available for the prevention of dengue fever and the containment of outbreaks. Photo-activated oxidants may represent promising tools for developing effective, safe and ecofriendly novel larvicides. The purpose of this study was to evaluate the potential of the synthetic meso-substituted porphyrin meso-tri(N-methylpyridyl), meso-mono(N-tetradecylpyridyl)porphine (C14) as a photoactivatable larvicide against the dengue vector Aedes (Stegomyia) aegypti. Methodology The photophysical and photochemical properties of the C14 molecule were assessed spectrophotometrically. Photomediated larvicidal efficacy, route of intake and site of action were determined on Ae. aegypti larvae by laboratory bioassays and fluorescence microscopy. Using powdered food pellet for laboratory rodents (a common larval food used in the laboratory) as a carrier for C14, loading-release dynamics, larvicidal efficacy and residual activity of the C14-carrier complex were investigated. Main Findings The C14 molecule was found to exert a potent photosensitizing activity on Ae. aegypti larvae. At irradiation intervals of 12 h and 1 h, at a light intensity of 4.0 mW/cm2, which is 50–100 times lower than that of natural sunlight, LC50 values of 0.1 µM (0.15 mg/l) and 0.5 µM (0.77 mg/l) were obtained, respectively. The molecule was active after ingestion by the larvae and caused irreversible, lethal damage to the midgut and caecal epithelia. The amphiphilic nature of C14 allowed a formulate to be produced that not only was as active against the larvae as C14 in solution, but also possessed a residual activity of at least two weeks, in laboratory conditions. Conclusions The meso-substituted synthetic porphyrin C14, thanks to its photo-sensitizing properties represents an attractive candidate for the development of novel photolarvicides for dengue vector control. PMID:22206031

  4. RNAi: antiviral therapy against dengue virus.

    PubMed

    Idrees, Sobia; Ashfaq, Usman A

    2013-03-01

    Dengue virus infection has become a global threat affecting around 100 countries in the world. Currently, there is no licensed antiviral agent available against dengue. Thus, there is a strong need to develop therapeutic strategies that can tackle this life threatening disease. RNA interference is an important and effective gene silencing process which degrades targeted RNA by a sequence specific process. Several studies have been conducted during the last decade to evaluate the efficiency of siRNA in inhibiting dengue virus replication. This review summarizes siRNAs as a therapeutic approach against dengue virus serotypes and concludes that siRNAs against virus and host genes can be next generation treatment of dengue virus infection.

  5. Dengue Fever, Hawaii, 2001–2002

    PubMed Central

    Pang, Lorrin; Kitsutani, Paul; Vorndam, Vance; Nakata, Michele; Ayers, Tracy; Elm, Joe; Tom, Tammy; Reiter, Paul; Rigau-Perez, José G.; Hayes, John M.; Mills, Kristin; Napier, Mike; Clark, Gary G.; Gubler, Duane J.

    2005-01-01

    Autochthonous dengue infections were last reported in Hawaii in 1944. In September 2001, the Hawaii Department of Health was notified of an unusual febrile illness in a resident with no travel history; dengue fever was confirmed. During the investigation, 1,644 persons with locally acquired denguelike illness were evaluated, and 122 (7%) laboratory-positive dengue infections were identified; dengue virus serotype 1 was isolated from 15 patients. No cases of dengue hemorrhagic fever or shock syndrome were reported. In 3 instances autochthonous infections were linked to a person who reported denguelike illness after travel to French Polynesia. Phylogenetic analyses showed the Hawaiian isolates were closely associated with contemporaneous isolates from Tahiti. Aedes albopictus was present in all communities surveyed on Oahu, Maui, Molokai, and Kauai; no Ae. aegypti were found. This outbreak underscores the importance of maintaining surveillance and control of potential disease vectors even in the absence of an imminent disease threat. PMID:15890132

  6. Dengue fever, Hawaii, 2001-2002.

    PubMed

    Effler, Paul V; Pang, Lorrin; Kitsutani, Paul; Vorndam, Vance; Nakata, Michele; Ayers, Tracy; Elm, Joe; Tom, Tammy; Reiter, Paul; Rigau-Perez, José G; Hayes, John M; Mills, Kristin; Napier, Mike; Clark, Gary G; Gubler, Duane J

    2005-05-01

    Autochthonous dengue infections were last reported in Hawaii in 1944. In September 2001, the Hawaii Department of Health was notified of an unusual febrile illness in a resident with no travel history; dengue fever was confirmed. During the investigation, 1,644 persons with locally acquired denguelike illness were evaluated, and 122 (7%) laboratory-positive dengue infections were identified; dengue virus serotype 1 was isolated from 15 patients. No cases of dengue hemorrhagic fever or shock syndrome were reported. In 3 instances autochthonous infections were linked to a person who reported denguelike illness after travel to French Polynesia. Phylogenetic analyses showed the Hawaiian isolates were closely associated with contemporaneous isolates from Tahiti. Aedes albopictus was present in all communities surveyed on Oahu, Maui, Molokai, and Kauai; no Ae. aegypti were found. This outbreak underscores the importance of maintaining surveillance and control of potential disease vectors even in the absence of an imminent disease threat.

  7. Underdiagnosis of dengue--Laredo, Texas, 1999.

    PubMed

    2001-02-02

    Dengue outbreaks have been reported in communities along the Mexico-U.S. border since 1980; however, during 1987-July 1999, no cases were reported from Laredo, Texas (1999 population: 162,000). During January-July 1999, approximately 300-325 dengue cases were reported from Nuevo Laredo, Tamaulipas, Mexico (1999 population: 274,000), a city across the Rio Grande from Laredo. To determine whether undiagnosed or unreported dengue cases had occurred in Laredo, the Texas Department of Health (TDH) reviewed medical records from five Laredo health facilities (the two city hospitals and the three largest of five community clinics). This report summarizes the findings of the review, which indicated that during July 23-August 20, 1999, 50% of suspected case-patients had undiagnosed dengue infection. Recognition of the diagnosis of dengue can be improved through heightened surveillance, professional and public education, and prompt reporting of cases by the health-care providers to local or state health departments.

  8. Dissecting Japan's Dengue Outbreak in 2014

    PubMed Central

    Quam, Mikkel B.; Sessions, October; Kamaraj, Uma Sangumathi; Rocklöv, Joacim; Wilder-Smith, Annelies

    2016-01-01

    Despite Japan's temperate climate, a dengue outbreak occurred in Tokyo for the first time in over 70 years in 2014. We dissected this dengue outbreak based on phylogenetic analysis, travel interconnectivity, and environmental drivers for dengue epidemics. Comparing the available dengue virus 1 (DENV1) E gene sequence from this outbreak with 3,282 unique DENV1 sequences in National Center for Biotechnology Information suggested that the DENV might have been imported from China, Indonesia, Singapore, or Vietnam. With travelers arriving into Japan, Guangzhou (China) may have been the source of DENV introduction, given that Guangzhou also reported a large-scale dengue outbreak in 2014. Coinciding with the 2014 outbreak, Tokyo's climate conditions permitted the amplification of Aedes vectors and the annual peak of vectorial capacity. Given suitable vectors and climate conditions in addition to increasing interconnectivity with endemic areas of Asia, Tokyo's 2014 outbreak did not come as a surprise and may foretell more to come. PMID:26711518

  9. Dengue fever: a Wikipedia clinical review.

    PubMed

    Heilman, James M; De Wolff, Jacob; Beards, Graham M; Basden, Brian J

    2014-01-01

    Dengue fever, also known as breakbone fever, is a mosquito-borne infectious tropical disease caused by the dengue virus. Symptoms include fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles. In a small proportion of cases, the disease develops into life-threatening dengue hemorrhagic fever, which results in bleeding, thrombocytopenia, and leakage of blood plasma, or into dengue shock syndrome, in which dangerously low blood pressure occurs. Treatment of acute dengue fever is supportive, with either oral or intravenous rehydration for mild or moderate disease and use of intravenous fluids and blood transfusion for more severe cases. Along with attempts to eliminate the mosquito vector, work is ongoing to develop a vaccine and medications targeted directly at the virus.

  10. Designing a vaccination strategy against dengue.

    PubMed

    Amaku, Marcos; Coudeville, Laurent; Massad, Eduardo

    2012-10-01

    In this work we propose a mathematical approach to estimate the dengue force of infection, the average age of dengue first infection, the optimum age to vaccinate children against dengue in a routine fashion and the optimum age interval to introduce the dengue vaccine in a mass vaccination campaign. The model is based on previously published models for vaccination against other childhood infections, which resulted in actual vaccination programmes in Brazil. The model was applied for three areas of distinct levels of endemicity of the city of Recife in Northeastern State of Pernambuco, Brazil. Our results point to an optimal age to introduce the dengue vaccine in the routine immunization programme at two years of age and an age interval to introduce a mass vaccination between three and 14 years of age.

  11. [Inequities in health: the case of dengue].

    PubMed

    Vanlerberghe, Veerle; Verdonck, Kristien

    2013-01-01

    Impoverished populations carry a disproportionately high share of the burden of neglected tropical diseases, including dengue. The burden of dengue is high among poor people because they often live in communities where mosquito vectors are abundant, because they use less vector-human barrier methods, and because interventions tend to be less effective in disadvantaged populations. We believe that a better understanding and management of the "causes behind the causes" of dengue would lead to more equitable and more effective control strategies. Two main ideas are worked out. First, we propose targeted interventions in well-defined geographical areas with high risk of dengue transmission. The definition of these high-risk areas should be based on socio-economical, entomological, environmental as well as epidemiological information. Second, there is a need to adapt dengue control tools to local, context-specific factors, in active collaboration with the sectors involved in risk management as well as with the affected communities.

  12. Severe Dengue Fever Outbreak in Taiwan

    PubMed Central

    Wang, Sheng-Fan; Wang, Wen-Hung; Chang, Ko; Chen, Yen-Hsu; Tseng, Sung-Pin; Yen, Chia-Hung; Wu, Deng-Chyang; Chen, Yi-Ming Arthur

    2016-01-01

    Dengue fever (DF) is a vector-borne disease caused by dengue viruses (DENVs). Epidemic dengue occurs intermittently in Taiwan. In 2014, Taiwan experienced its largest DF outbreak. There were 15,732 DF cases reported. There were a total of 136 dengue hemorrhagic fever (DHF) cases, of which 20 resulted in death. Most DF cases were reported in southern Taiwan. A total of 15,043 (96%) cases were from Kaohsiung, a modern city in southern Taiwan. This report reviews DF epidemics in Taiwan during 2005–2014. The correlation between DF and DHF along with temperature and precipitation were conjointly examined. We conclude that most dengue epidemics in Taiwan resulted from imported DF cases. Results indicate three main factors that may have been associated with this DF outbreak in Kaohsiung: an underground pipeline explosion combined with subsequent rainfall and higher temperature. These factors may have enhanced mosquito breeding activity, facilitating DENV transmission. PMID:26572871

  13. Real-time forecasts of dengue epidemics

    NASA Astrophysics Data System (ADS)

    Yamana, T. K.; Shaman, J. L.

    2015-12-01

    Dengue is a mosquito-borne viral disease prevalent in the tropics and subtropics, with an estimated 2.5 billion people at risk of transmission. In many areas with endemic dengue, disease transmission is seasonal but prone to high inter-annual variability with occasional severe epidemics. Predicting and preparing for periods of higher than average transmission is a significant public health challenge. Here we present a model of dengue transmission and a framework for optimizing model simulations with real-time observational data of dengue cases and environmental variables in order to generate ensemble-based forecasts of the timing and severity of disease outbreaks. The model-inference system is validated using synthetic data and dengue outbreak records. Retrospective forecasts are generated for a number of locations and the accuracy of these forecasts is quantified.

  14. Governmental supervision and rapid detection on dengue vectors: An important role for dengue control in China.

    PubMed

    Guo, Yu-Hong; Lai, Sheng-jie; Liu, Xiao-Bo; Li, Gui-Chang; Yu, Hong-Jie; Liu, Qi-Yong

    2016-04-01

    China experienced an unprecedented outbreak of dengue fever in 2014, the National Health and Family Planning Commission of the People's Republic of China (NHFPC) carried out a series of supervision work on integrated vector management (IVM), and Chinese Center for Disease Control and Prevention (China CDC) conducted a rapid detection on vector density in some areas with high dengue incidence. The goal of this study was to explain the effect of these actions, which play an important role for dengue control, and we wish to give a good example for dengue control in China, even in the world. Compare mosquito vector density with Breteau Index (BI) and dengue incidence after or along with control work vs. before. Data was entered and analyzed by Microsoft Excel 2007 and SPSS19.0. Average value of BI from 22.82 in September dropped to 3.93 along with supervision and rapid detection. BI showed a significant decrease (paired sample t-test, t=3.061, P=0.018≺0.05). Dengue incidence decreased gradually along with supervision and rapid detection. Supervised work on IVM by NHFPC and the rapid detection on dengue vector Aedes by China CDC promoted to cut down the dengue vector density, then reduced dengue incidence; both played an important role for dengue control throughout China in 2014. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Morbidity Rate Prediction of Dengue Hemorrhagic Fever (DHF) Using the Support Vector Machine and the Aedes aegypti Infection Rate in Similar Climates and Geographical Areas

    PubMed Central

    Kesorn, Kraisak; Ongruk, Phatsavee; Chompoosri, Jakkrawarn; Phumee, Atchara; Thavara, Usavadee; Tawatsin, Apiwat; Siriyasatien, Padet

    2015-01-01

    Background In the past few decades, several researchers have proposed highly accurate prediction models that have typically relied on climate parameters. However, climate factors can be unreliable and can lower the effectiveness of prediction when they are applied in locations where climate factors do not differ significantly. The purpose of this study was to improve a dengue surveillance system in areas with similar climate by exploiting the infection rate in the Aedes aegypti mosquito and using the support vector machine (SVM) technique for forecasting the dengue morbidity rate. Methods and Findings Areas with high incidence of dengue outbreaks in central Thailand were studied. The proposed framework consisted of the following three major parts: 1) data integration, 2) model construction, and 3) model evaluation. We discovered that the Ae. aegypti female and larvae mosquito infection rates were significantly positively associated with the morbidity rate. Thus, the increasing infection rate of female mosquitoes and larvae led to a higher number of dengue cases, and the prediction performance increased when those predictors were integrated into a predictive model. In this research, we applied the SVM with the radial basis function (RBF) kernel to forecast the high morbidity rate and take precautions to prevent the development of pervasive dengue epidemics. The experimental results showed that the introduced parameters significantly increased the prediction accuracy to 88.37% when used on the test set data, and these parameters led to the highest performance compared to state-of-the-art forecasting models. Conclusions The infection rates of the Ae. aegypti female mosquitoes and larvae improved the morbidity rate forecasting efficiency better than the climate parameters used in classical frameworks. We demonstrated that the SVM-R-based model has high generalization performance and obtained the highest prediction performance compared to classical models as measured by

  16. Vitamin D serostatus and dengue fever progression to dengue hemorrhagic fever/dengue shock syndrome.

    PubMed

    Villamor, E; Villar, L A; Lozano, A; Herrera, V M; Herrán, O F

    2017-09-14

    Vitamin D could modulate pathways leading to dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). We examined the associations of serum total 25-hydroxy vitamin D [25(OH)D] and vitamin D binding protein (VDBP) concentrations in patients with uncomplicated dengue fever (DF) with risk of progression to DHF/DSS. In a case-control study nested in a cohort of DF patients who were followed during the acute episode in Bucaramanga, Colombia, we compared 25(OH)D and VDBP at onset of fever between 110 cases who progressed to DHF/DSS and 235 DF controls who did not progress. 25(OH)D concentrations were also compared between the acute sample and a sample collected >1 year post-convalescence in a subgroup. Compared with 25(OH)D ⩾75 nmol/l, adjusted odds ratios (95% CI) for progression were 0·44 (0·22-0·88) and 0·13 (0·02-1·05) for 50 to 75 nmol/l (vitamin D insufficiency) and <50 nmol/l (vitamin D deficiency), respectively (P, trend = 0·003). Mean 25(OH)D concentrations were much lower post-convalescence compared with the acute episode, regardless of case status. Compared with controls, mean VDBP was non-significantly lower in cases. We conclude that low serum 25(OH)D concentrations in DF patients predict decreased odds of progression to DHF/DSS.

  17. Ongoing dengue epidemic - Angola, June 2013.

    PubMed

    2013-06-21

    On April 1, 2013, the Public Health Directorate of Angola announced that six cases of dengue had been reported to the Ministry of Health of Angola (MHA). As of May 31, a total of 517 suspected dengue cases had been reported and tested for dengue with a rapid diagnostic test (RDT). A total of 313 (60.5%) specimens tested positive for dengue, including one from a patient who died. All suspected cases were reported from Luanda Province, except for two from Malanje Province. Confirmatory diagnostic testing of 49 specimens (43 RDT-positive and six RDT-negative) at the CDC Dengue Branch confirmed dengue virus (DENV) infection in 100% of the RDT-positive specimens and 50% of the RDT-negative specimens. Only DENV-1 was detected by molecular diagnostic testing. Phylogenetic analysis indicated this virus has been circulating in the region since at least 1968, strongly suggesting that dengue is endemic in Angola. Health-care professionals throughout Angola should be aware of the ongoing epidemic, the recommended practices for clinical management of dengue patients, and the need to report cases to MHA. Persons in Angola should seek medical care for acute febrile illness to reduce the risk for developing complications. Laboratory-confirmed dengue also has been reported from seven countries on four continents among persons who had recently traveled to Luanda, including 79 persons from Portugal. Angola is the third of four African countries to report a dengue outbreak in 2013. Persons returning from Africa with acute febrile illness should seek medical care, including testing for DENV infection, and suspected cases should be reported to public health authorities.

  18. Behavioural fever in zebrafish larvae.

    PubMed

    Rey, Sonia; Moiche, Visila; Boltaña, Sebastian; Teles, Mariana; MacKenzie, Simon

    2017-02-01

    Behavioural fever has been reported in different species of mobile ectotherms including the zebrafish, Danio rerio, in response to exogenous pyrogens. In this study we report, to our knowledge for the first time, upon the ontogenic onset of behavioural fever in zebrafish (Danio rerio) larvae. For this, zebrafish larvae (from first feeding to juveniles) were placed in a continuous thermal gradient providing the opportunity to select their preferred temperature. The novel thermal preference aquarium was based upon a continuous vertical column system and allows for non-invasive observation of larvae vertical distribution under isothermal (TR at 28 °C) and thermal gradient conditions (TCH: 28-32 °C). Larval thermal preference was assessed under both conditions with or without an immersion challenge, in order to detect the onset of the behavioural fever response. Our results defined the onset of the dsRNA induced behavioural fever at 18-20 days post fertilization (dpf). Significant differences were observed in dsRNA challenged larvae, which prefer higher temperatures (1-4 °C increase) throughout the experimental period as compared to non-challenged larvae. In parallel we measured the abundance of antiviral transcripts; viperin, gig2, irf7, trim25 and Mxb mRNAs in dsRNA challenged larvae under both thermal regimes: TR and TCh. Significant increases in the abundance of all measured transcripts were recorded under thermal choice conditions signifying that thermo-coupling and the resultant enhancement of the immune response to dsRNA challenge occurs from 18 dpf onwards in the zebrafish. The results are of importance as they identify a key developmental stage where the neuro-immune interface matures in the zebrafish likely providing increased resistance to viral infection.

  19. Tree holes as larval habitats for Aedes aegypti in urban, suburban and forest habitats in a dengue affected area.

    PubMed

    Mangudo, C; Aparicio, J P; Gleiser, R M

    2015-12-01

    Aedes aegypti (L.) (Diptera: Culicidae), the main vector of dengue and urban yellow fever in the world, is highly adapted to the human environment. Artificial containers are the most common larval habitat for the species, but it may develop in tree holes and other phytotelmata. This study assessed whether tree holes in San Ramón de la Nueva Orán, a city located in subtropical montane moist forest where dengue outbreaks occur, are relevant as larval habitat for Ae. aegypti and if the species may be found in natural areas far from human habitations. Water holding tree holes were sampled during 3 years once a month along the rainy season using a siphon bottle, in urban and suburban sites within the city and in adjacent forested areas. Larvae and pupae were collected and the presence and volume of water in each tree hole were recorded. Finding Ae. aegypti in forested areas was an isolated event; however, the species was frequently collected from tree holes throughout the city and along the sampling period. Moreover, larvae were collected in considerably high numbers, stressing the importance of taking into account these natural cavities as potential reinfestation foci within dengue control framework.

  20. Antibody-Dependent Enhancement of Dengue Virus Growth in Human Monocytes as a Risk Factor for Dengue Hemorrhagic Fever

    DTIC Science & Technology

    1989-01-01

    Clamfication) Antibody-Dependent Enhancement of Dengue Virus Growth in Human Monocytes as a Risk Factor for Dengue Hemorrhagic Fever 𔃼 PERSONAL AjTHOR(S...FELD GROUP SUBGROUP Antibody-Dependent Enhancement of Dengue Virus Growth in Human Monocytes as a Risk Factor for Dengue Hemorrhagic Fever. 19...ABSTRAC7 (Continue on reverse if necessary and identify by block number) Serum specimens~collected during a prospective study of dengue infections among

  1. Larvicidal Activity of Cassia occidentalis (Linn.) against the Larvae of Bancroftian Filariasis Vector Mosquito Culex quinquefasciatus

    PubMed Central

    Kumar, Deepak; Chawla, Rakesh; Dhamodaram, P.; Balakrishnan, N.

    2014-01-01

    Background & Objectives. The plan of this work was to study the larvicidal activity of Cassia occidentalis (Linn.) against the larvae of Culex quinquefasciatus. These larvae are the most significant vectors. They transmit the parasites and pathogens which cause a deadly disease like filariasis, dengue, yellow fever, malaria, Japanese encephalitis, chikungunya, and so forth, which are considered harmful towards the population in tropic and subtropical regions. Methods. The preliminary laboratory trail was undertaken to determine the efficacy of petroleum ether and N-butanol extract of dried whole plant of Cassia occidentalis (Linn.) belonging to the family Caesalpiniaceae at various concentrations against the late third instar larvae of Culex quinquefasciatus by following the WHO guidelines. Results. The results suggest that 100% mortality effect of petroleum ether and N-butanol extract of Cassia occidentalis (Linn.) was observed at 200 and 300 ppm (parts per million). The results obviously showed use of plants in insect control as an alternative method for minimizing the noxious effect of some pesticide compounds on the environment. Thus the extract of Cassia occidentalis (Linn.) is claimed as more selective and biodegradable agent. Conclusion. This study justified that plant Cassia occidentalis (Linn.) has a realistic mortality result for larvae of filarial vector. This is safe to individual and communities against mosquitoes. It is a natural weapon for mosquito control. PMID:24688786

  2. QTL mapping of genome regions controlling temephos resistance in larvae of the mosquito Aedes aegypti.

    PubMed

    Reyes-Solis, Guadalupe Del Carmen; Saavedra-Rodriguez, Karla; Suarez, Adriana Flores; Black, William C

    2014-10-01

    The mosquito Aedes aegypti is the principal vector of dengue and yellow fever flaviviruses. Temephos is an organophosphate insecticide used globally to suppress Ae. aegypti larval populations but resistance has evolved in many locations. Quantitative Trait Loci (QTL) controlling temephos survival in Ae. aegypti larvae were mapped in a pair of F3 advanced intercross lines arising from temephos resistant parents from Solidaridad, México and temephos susceptible parents from Iquitos, Peru. Two sets of 200 F3 larvae were exposed to a discriminating dose of temephos and then dead larvae were collected and preserved for DNA isolation every two hours up to 16 hours. Larvae surviving longer than 16 hours were considered resistant. For QTL mapping, single nucleotide polymorphisms (SNPs) were identified at 23 single copy genes and 26 microsatellite loci of known physical positions in the Ae. aegypti genome. In both reciprocal crosses, Multiple Interval Mapping identified eleven QTL associated with time until death. In the Solidaridad×Iquitos (SLD×Iq) cross twelve were associated with survival but in the reciprocal IqxSLD cross, only six QTL were survival associated. Polymorphisms at acetylcholine esterase (AchE) loci 1 and 2 were not associated with either resistance phenotype suggesting that target site insensitivity is not an organophosphate resistance mechanism in this region of México. Temephos resistance is under the control of many metabolic genes of small effect and dispersed throughout the Ae. aegypti genome.

  3. QTL Mapping of Genome Regions Controlling Temephos Resistance in Larvae of the Mosquito Aedes aegypti

    PubMed Central

    Reyes-Solis, Guadalupe del Carmen; Saavedra-Rodriguez, Karla; Suarez, Adriana Flores; Black, William C.

    2014-01-01

    Introduction The mosquito Aedes aegypti is the principal vector of dengue and yellow fever flaviviruses. Temephos is an organophosphate insecticide used globally to suppress Ae. aegypti larval populations but resistance has evolved in many locations. Methodology/Principal Findings Quantitative Trait Loci (QTL) controlling temephos survival in Ae. aegypti larvae were mapped in a pair of F3 advanced intercross lines arising from temephos resistant parents from Solidaridad, México and temephos susceptible parents from Iquitos, Peru. Two sets of 200 F3 larvae were exposed to a discriminating dose of temephos and then dead larvae were collected and preserved for DNA isolation every two hours up to 16 hours. Larvae surviving longer than 16 hours were considered resistant. For QTL mapping, single nucleotide polymorphisms (SNPs) were identified at 23 single copy genes and 26 microsatellite loci of known physical positions in the Ae. aegypti genome. In both reciprocal crosses, Multiple Interval Mapping identified eleven QTL associated with time until death. In the Solidaridad×Iquitos (SLD×Iq) cross twelve were associated with survival but in the reciprocal IqxSLD cross, only six QTL were survival associated. Polymorphisms at acetylcholine esterase (AchE) loci 1 and 2 were not associated with either resistance phenotype suggesting that target site insensitivity is not an organophosphate resistance mechanism in this region of México. Conclusions/Significance Temephos resistance is under the control of many metabolic genes of small effect and dispersed throughout the Ae. aegypti genome. PMID:25330200

  4. The use of Aedes aegypti larvae attractants to enhance the effectiveness of larvicides.

    PubMed

    Gonzalez, Paula V; Harburguer, Laura; González-Audino, Paola A; Masuh, Héctor M

    2016-06-01

    Aedes aegypti (L.) is an important dengue, chikungunya, and yellow fever vector. Immature stages of this species inhabit human-made containers placed in residential landscapes, and the application of larvicides inside containers that cannot be eliminated is still considered a priority in control programs. Larvicidal efficacy is influenced by several factors, including the formulation used, the water quality, and the susceptibility of larvae, among others. If an attractant can be incorporated into a slow-release larvicide formulation, it will be feasible to direct the larvae into the source of insecticide and thereby improving its efficacy. We studied the influence of 1-octen-3ol and 3-methylphenol on the rate of Ae. aegypti larvae mortality using the larvicides Bacillus thuringiensis var. israelensis (Bti), temephos, and spinosad. These chemicals were combined with the larvicides mixed with agar during the bioassays. Mortality was registered every 10 min, and a lethal time 50 (LT50) was calculated. The inclusion of the Ae. aegypti larvae attractants with the larvicides into a solid agar matrix improved their efficiency obtaining a strong and marked reduction in the LT50 compared with the use of larvicides alone.

  5. Metarhizium anisopliae Pathogenesis of Mosquito Larvae: A Verdict of Accidental Death

    PubMed Central

    Butt, Tariq M.; Greenfield, Bethany P. J.; Greig, Carolyn; Maffeis, Thierry G. G.; Taylor, James W. D.; Piasecka, Justyna; Dudley, Ed; Abdulla, Ahmed; Dubovskiy, Ivan M.; Garrido-Jurado, Inmaculada; Quesada-Moraga, Enrique; Penny, Mark W.; Eastwood, Daniel C.

    2013-01-01

    Metarhizium anisopliae, a fungal pathogen of terrestrial arthropods, kills the aquatic larvae of Aedes aegypti, the vector of dengue and yellow fever. The fungus kills without adhering to the host cuticle. Ingested conidia also fail to germinate and are expelled in fecal pellets. This study investigates the mechanism by which this fungus adapted to terrestrial hosts kills aquatic mosquito larvae. Genes associated with the M. anisopliae early pathogenic response (proteinases Pr1 and Pr2, and adhesins, Mad1 and Mad2) are upregulated in the presence of larvae, but the established infection process observed in terrestrial hosts does not progress and insecticidal destruxins were not detected. Protease inhibitors reduce larval mortality indicating the importance of proteases in the host interaction. The Ae. aegypti immune response to M. anisopliae appears limited, whilst the oxidative stress response gene encoding for thiol peroxidase is upregulated. Cecropin and Hsp70 genes are downregulated as larval death occurs, and insect mortality appears to be linked to autolysis through caspase activity regulated by Hsp70 and inhibited, in infected larvae, by protease inhibitors. Evidence is presented that a traditional host-pathogen response does not occur as the species have not evolved to interact. M. anisopliae retains pre-formed pathogenic determinants which mediate host mortality, but unlike true aquatic fungal pathogens, does not recognise and colonise the larval host. PMID:24349111

  6. Effect of Myracrodruon urundeuva leaf lectin on survival and digestive enzymes of Aedes aegypti larvae.

    PubMed

    Napoleão, Thiago Henrique; Pontual, Emmanuel Viana; de Albuquerque Lima, Thâmarah; de Lima Santos, Nataly Diniz; Sá, Roberto Araújo; Coelho, Luana Cassandra Breitenbach Barroso; do Amaral Ferraz Navarro, Daniela Maria; Paiva, Patrícia Maria Guedes

    2012-02-01

    Aedes aegypti transmits the viruses that cause yellow and dengue fevers. Vector control is essential, since a vaccine for dengue has not as yet been made available. This work reports on the larvicidal activity of Myracrodruon urundeuva leaf lectin (MuLL) against A. aegypti fourth-stage larvae (L(4)). Also, the resistance of MuLL to digestion by L(4) gut proteases and the effects of MuLL on protease, trypsin-like and α-amylase activities from L(4) gut were evaluated to determine if lectin remains active in A. aegypti gut and if insect enzyme activities can be modulated by MuLL. MuLL promoted mortality of L(4) with LC(50) of 0.202 mg/ml. Haemagglutinating activity of MuLL was detected even after incubation for 96 h with L(4) gut preparation containing protease activity. MuLL affected the activity of gut enzymes, inhibiting protease and trypsin activities and stimulating α-amylase activity. The results suggest that MuLL may become a new biodegradable larvicidal agent for dengue control. Larvicidal activity of MuLL may be linked to its resistance to proteolysis by larval enzymes and interference in the activity of digestive larval enzymes.

  7. Vertical transmission of dengue viruses by strains of Aedes albopictus recently introduced into Brazil.

    PubMed

    Mitchell, C J; Miller, B R

    1990-06-01

    Three strains of Aedes albopictus from Brazil were examined for their ability to vertically transmit dengue 1 (DEN-1) and dengue 4 (DEN-4) viruses. Parental females were uniformly infected by parenteral inoculation of virus, and 8,121 F1 progeny from DEN-1 and DEN-4 infected mothers were pooled in lots of approximately 50 and tested for virus. Seven of 60 pools were positive for DEN-1 virus, and 1 of 121 pools was positive for DEN-4 virus. In DEN-1 assays, the minimum infection rate (MIR) for larvae (2 pools tested) was 1:84. Among positive cohorts of adults, pooled by sex and by geographic strain of mosquito, the MIR ranged from 1:193 to 1:626 for males and from 1:187 to 1:311 for females. Only a single pool of adult females was positive for DEN-4 virus (MIR 1:1022 for an adult female cohort from Santa Teresa). These results indicate that Brazilian Ae. albopictus have the potential to play a role in the maintenance of dengue viruses in nature.

  8. Role of cognitive parameters in dengue hemorrhagic fever and dengue shock syndrome

    PubMed Central

    2013-01-01

    Dengue is becoming recognized as one of the most important vector-borne human diseases. It is predominant in tropical and subtropical zones but its geographical distribution is progressively expanding, making it an escalating global health problem of today. Dengue presents with spectrum of clinical manifestations, ranging from asymptomatic, undifferentiated mild fever, dengue fever (DF), to dengue hemorrhagic fever (DHF) with or without shock (DSS), a life-threatening illness characterized by plasma leakage due to increased vascular permeability. Currently, there are no antiviral modalities or vaccines available to treat and prevent dengue. Supportive care with close monitoring is the standard clinical practice. The mechanisms leading to DHF/DSS remains poorly understood. Multiple factors have been attributed to the pathological mechanism, but only a couple of these hypotheses are popular in scientific circles. The current discussion focuses on underappreciated factors, temperature, natural IgM, and endotoxin, which may be critical components playing roles in dengue pathogenesis. PMID:24305068

  9. A recombinant, chimeric tetravalent dengue vaccine candidate based on a dengue virus serotype 2 backbone.

    PubMed

    Osorio, Jorge E; Wallace, Derek; Stinchcomb, Dan T

    2016-01-01

    Dengue fever is caused by infection with one of four dengue virus (DENV) serotypes (DENV-1-4), necessitating tetravalent dengue vaccines that can induce protection against all four DENV. Takeda's live attenuated tetravalent dengue vaccine candidate (TDV) comprises an attenuated DENV-2 strain plus chimeric viruses containing the prM and E genes of DENV-1, -3 and -4 cloned into the attenuated DENV-2 'backbone'. In Phase 1 and 2 studies, TDV was well tolerated by children and adults aged 1.5-45 years, irrespective of prior dengue exposure; mild injection-site symptoms were the most common adverse events. TDV induced neutralizing antibody responses and seroconversion to all four DENV as well as cross-reactive T cell-mediated responses that may be necessary for broad protection against dengue fever.

  10. Sediment bioassays with oyster larvae

    SciTech Connect

    Chapman, P.M.; Morgan, J.D.

    1983-10-01

    Tests with naturally-occurring sediments are rare and sediment testing methodology is not standardized. The authors present a simple methodology for undertaking sediment bioassays with oyster larvae, and present data from a recent study to prove the utility of this method.

  11. DengueTools: innovative tools and strategies for the surveillance and control of dengue

    PubMed Central

    Wilder-Smith, Annelies; Renhorn, Karl-Erik; Tissera, Hasitha; Abu Bakar, Sazaly; Alphey, Luke; Kittayapong, Pattamaporn; Lindsay, Steve; Logan, James; Hatz, Christoph; Reiter, Paul; Rocklöv, Joacim; Byass, Peter; Louis, Valérie R.; Tozan, Yesim; Massad, Eduardo; Tenorio, Antonio; Lagneau, Christophe; L'Ambert, Grégory; Brooks, David; Wegerdt, Johannah; Gubler, Duane

    2012-01-01

    Dengue fever is a mosquito-borne viral disease estimated to cause about 230 million infections worldwide every year, of which 25,000 are fatal. Global incidence has risen rapidly in recent decades with some 3.6 billion people, over half of the world's population, now at risk, mainly in urban centres of the tropics and subtropics. Demographic and societal changes, in particular urbanization, globalization, and increased international travel, are major contributors to the rise in incidence and geographic expansion of dengue infections. Major research gaps continue to hamper the control of dengue. The European Commission launched a call under the 7th Framework Programme with the title of ‘Comprehensive control of Dengue fever under changing climatic conditions’. Fourteen partners from several countries in Europe, Asia, and South America formed a consortium named ‘DengueTools’ to respond to the call to achieve better diagnosis, surveillance, prevention, and predictive models and improve our understanding of the spread of dengue to previously uninfected regions (including Europe) in the context of globalization and climate change. The consortium comprises 12 work packages to address a set of research questions in three areas: Research area 1: Develop a comprehensive early warning and surveillance system that has predictive capability for epidemic dengue and benefits from novel tools for laboratory diagnosis and vector monitoring. Research area 2: Develop novel strategies to prevent dengue in children. Research area 3: Understand and predict the risk of global spread of dengue, in particular the risk of introduction and establishment in Europe, within the context of parameters of vectorial capacity, global mobility, and climate change. In this paper, we report on the rationale and specific study objectives of ‘DengueTools’. DengueTools is funded under the Health theme of the Seventh Framework Programme of the European Community, Grant Agreement Number: 282589

  12. Vaccines and immunization strategies for dengue prevention

    PubMed Central

    Liu, Yang; Liu, Jianying; Cheng, Gong

    2016-01-01

    Dengue is currently the most significant arboviral disease afflicting tropical and sub-tropical countries worldwide. Dengue vaccines, such as the multivalent attenuated, chimeric, DNA and inactivated vaccines, have been developed to prevent dengue infection in humans, and they function predominantly by stimulating immune responses against the dengue virus (DENV) envelope (E) and nonstructural-1 proteins (NS1). Of these vaccines, a live attenuated chimeric tetravalent DENV vaccine developed by Sanofi Pasteur has been licensed in several countries. However, this vaccine renders only partial protection against the DENV2 infection and is associated with an unexplained increased incidence of hospitalization for severe dengue disease among children younger than nine years old. In addition to the virus-based vaccines, several mosquito-based dengue immunization strategies have been developed to interrupt the vector competence and effectively reduce the number of infected mosquito vectors, thus controlling the transmission of DENV in nature. Here we summarize the recent progress in the development of dengue vaccines and novel immunization strategies and propose some prospective vaccine strategies for disease prevention in the future. PMID:27436365

  13. Vaccines and immunization strategies for dengue prevention.

    PubMed

    Liu, Yang; Liu, Jianying; Cheng, Gong

    2016-07-20

    Dengue is currently the most significant arboviral disease afflicting tropical and sub-tropical countries worldwide. Dengue vaccines, such as the multivalent attenuated, chimeric, DNA and inactivated vaccines, have been developed to prevent dengue infection in humans, and they function predominantly by stimulating immune responses against the dengue virus (DENV) envelope (E) and nonstructural-1 proteins (NS1). Of these vaccines, a live attenuated chimeric tetravalent DENV vaccine developed by Sanofi Pasteur has been licensed in several countries. However, this vaccine renders only partial protection against the DENV2 infection and is associated with an unexplained increased incidence of hospitalization for severe dengue disease among children younger than nine years old. In addition to the virus-based vaccines, several mosquito-based dengue immunization strategies have been developed to interrupt the vector competence and effectively reduce the number of infected mosquito vectors, thus controlling the transmission of DENV in nature. Here we summarize the recent progress in the development of dengue vaccines and novel immunization strategies and propose some prospective vaccine strategies for disease prevention in the future.

  14. Current issues in the economics of vaccination against dengue.

    PubMed

    Tozan, Yesim

    2016-01-01

    Dengue is a major public health concern in tropical and subtropical areas of the world. The prospects for dengue prevention have recently improved with the results of efficacy trials of a tetravalent dengue vaccine. Although partially effective, once licensed, its introduction can be a public health priority in heavily affected countries because of the perceived public health importance of dengue. This review explores the most immediate economic considerations of introducing a new dengue vaccine and evaluates the published economic analyses of dengue vaccination. Findings indicate that the current economic evidence base is of limited utility to support country-level decisions on dengue vaccine introduction. There are a handful of published cost-effectiveness studies and no country-specific costing studies to project the full resource requirements of dengue vaccine introduction. Country-level analytical expertise in economic analyses, another gap identified, needs to be strengthened to facilitate evidence-based decision-making on dengue vaccine introduction in endemic countries.

  15. How the pilidium larva feeds

    PubMed Central

    2013-01-01

    Introduction The nemertean pilidium is a long-lived feeding larva unique to the life cycle of a single monophyletic group, the Pilidiophora, which is characterized by this innovation. That the pilidium feeds on small planktonic unicells seems clear; how it does so is unknown and not readily inferred, because it shares little morphological similarity with other planktotrophic larvae. Results Using high-speed video of trapped lab-reared pilidia of Micrura alaskensis, we documented a multi-stage feeding mechanism. First, the external ciliation of the pilidium creates a swimming and feeding current which carries suspended prey past the primary ciliated band spanning the posterior margins of the larval body. Next, the larva detects prey that pass within reach, then conducts rapid and coordinated deformations of the larval body to re-direct passing cells and surrounding water into a vestibular space between the lappets, isolated from external currents but not quite inside the larva. Once a prey cell is thus captured, internal ciliary bands arranged within this vestibule prevent prey escape. Finally, captured cells are transported by currents within a buccal funnel toward the stomach entrance. Remarkably, we observed that the prey of choice – various cultured cryptomonads – attempt to escape their fate. Conclusions The feeding mechanism deployed by the pilidium larva coordinates local control of cilia-driven water transport with sensorimotor behavior, in a manner clearly distinct from any other well-studied larval feeding mechanisms. We hypothesize that the pilidium’s feeding strategy may be adapted to counter escape responses such as those deployed by cryptomonads, and speculate that similar needs may underlie convergences among disparate planktotrophic larval forms. PMID:23927417

  16. How the pilidium larva feeds.

    PubMed

    von Dassow, George; Emlet, Richard B; Maslakova, Svetlana A

    2013-08-09

    The nemertean pilidium is a long-lived feeding larva unique to the life cycle of a single monophyletic group, the Pilidiophora, which is characterized by this innovation. That the pilidium feeds on small planktonic unicells seems clear; how it does so is unknown and not readily inferred, because it shares little morphological similarity with other planktotrophic larvae. Using high-speed video of trapped lab-reared pilidia of Micrura alaskensis, we documented a multi-stage feeding mechanism. First, the external ciliation of the pilidium creates a swimming and feeding current which carries suspended prey past the primary ciliated band spanning the posterior margins of the larval body. Next, the larva detects prey that pass within reach, then conducts rapid and coordinated deformations of the larval body to re-direct passing cells and surrounding water into a vestibular space between the lappets, isolated from external currents but not quite inside the larva. Once a prey cell is thus captured, internal ciliary bands arranged within this vestibule prevent prey escape. Finally, captured cells are transported by currents within a buccal funnel toward the stomach entrance. Remarkably, we observed that the prey of choice - various cultured cryptomonads - attempt to escape their fate. The feeding mechanism deployed by the pilidium larva coordinates local control of cilia-driven water transport with sensorimotor behavior, in a manner clearly distinct from any other well-studied larval feeding mechanisms. We hypothesize that the pilidium's feeding strategy may be adapted to counter escape responses such as those deployed by cryptomonads, and speculate that similar needs may underlie convergences among disparate planktotrophic larval forms.

  17. Safety Testing of Dengue-2 and Dengue-4 Viruses for Use in Human Challenge Experiments

    DTIC Science & Technology

    1988-04-01

    16.6 IIJI 2 N ,RSLIO JS ’, %AN -T N ," 1 0 % :.i. AD Ln MC.tILE (UiO Safety Testinq of Dengue -2 and Denque-4 Viruses for Use in Human Chal, nqe...ELEMENT NO. NO. 3M16 NO. ACCESSION NO. 62770A 2770A871 AA 110 11. TITLE (Include Security Classification) Safety Testing of Dengue -2 and Dengue -4 Viruses...if necessary and identify by block number) FIELD GROUP SUB-GROUP Dengue Fever, Viruses, Mice, Rabbits, Guinea Pig, 06 13 Tropical Medicine, Virology

  18. "We need people to collaborate together against this disease": A qualitative exploration of perceptions of dengue fever control in caregivers' of children under 5 years, in the Peruvian Amazon.

    PubMed

    Frank, Amy L; Beales, Emily R; de Wildt, Gilles; Meza Sanchez, Graciela; Jones, Laura L

    2017-09-01

    Dengue Fever presents a significant and growing burden of disease to endemic countries, where children are at particular risk. Worldwide, no effective anti-viral treatment has been identified, thus vector control is key for disease prevention, particularly in Peru where no vaccine is currently available. This qualitative study aimed to explore the perceptions of dengue control in caregivers' of children under 5 years in Peru, to help direct future mosquito control programmes and strategy. Eighteen semi-structured interviews were conducted in one health centre in Iquitos, Peru. Interviews were audio-recorded, transcribed and translated by an independent translator. Data were analysed using an inductive thematic approach. Three core analytic themes were interpreted: (1) awareness of dengue and its control, (2) perceived susceptibility of children, rural riverside communities and city inhabitants, and (3) perceived responsibility of vector control. Participants were aware of dengue symptoms, transmission and larvae eradication strategies. Misconceptions about the day-time biting behaviour of the Aedes aegypti mosquito and confusion with other mosquito-borne diseases influenced preventative practice. Community-wide lack of cooperation was recognised as a key barrier. This was strengthened by attitudes that the government or health centre were responsible for dengue control and a belief that the disease cannot be prevented through individual actions. Participants felt powerless to prevent dengue due to assumed inevitability of infection and lack of faith in preventative practices. However, children and rural communities were believed to be most vulnerable. Perceptions of dengue control amongst caregivers to under 5's were important in shaping their likelihood to participate in preventative practices. There is a need to address the perceived lack of community cooperation through strategies creating a sense of ownership of community control and enhancing social

  19. [Aedes albopictus, vector of chikungunya and dengue viruses in Reunion Island: biology and control].

    PubMed

    Delatte, H; Paupy, C; Dehecq, J S; Thiria, J; Failloux, A B; Fontenille, D

    2008-03-01

    Chikungunya virus (CHIKV) and dengue virus (DENV) are mosquito-borne viruses transmitted by the Aedes genus. Dengue is considered as the most important arbovirus disease throughout the World. Chikungunya, known from epidemics in continental Africa and Asia, has up to now been poorly studied. It has been recently responsible for the severe 2004-2007 epidemic reported in the Indian Ocean (IO), which has caused several serious health and economic problems. This unprecedented epidemic of the IO has shown severe health troubles with morbidity and death associated, which had never been observed before. The two major vectors of those arboviruses in the IO area are Aedes aegypti and Aedes albopictus. The latest is considered as the main vector in most of the islands of the area, especially in Reunion Island. Ae. albopictus showed strong ecological plasticity. Small disposable containers were the principal urban breeding sites, and preferred natural developmental sites were bamboo stumps and rock holes in peri-urban and gully areas. The virus has been isolated from field collected Ae. albopictus females, and in two out of 500 pools of larvae, demonstrating vertical transmission. Experimental works showed that both Ae. albopictus and Ae. aegypti from west IO islands are efficient vectors of dengue and chikungunya viruses. Since 2006 and all along the epidemic of CHIKV, measures for the control of larvae (temephos then Bacillus thuringiensis) and adults (fenitrothion, then deltamethrine) of Ae. albopictus where applied along with individual and collective actions (by the use of repellents, and removal of breeding sites around houses) in Reunion Island. In order to prevent such epidemics, a preventive plan for arboviruses upsurge is ongoing processed. This plan would allow a quicker response to the threat and adapt it according to the virus and its specific vector.

  20. Workbook on the Identification of Mosquito Larvae.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; And Others

    This self-instructional booklet is designed to enable public health workers identify larvae of some important North American mosquito species. The morphological features of larvae of the various genera and species are illustrated in a programed booklet, which also contains illustrated taxonomic keys to the larvae of 11 North American genera and to…

  1. Non-hemorrhagic dengue fever with rhabdomyolysis.

    PubMed

    Jha, Ratan; Gude, Dilip; Chennamsetty, Sashidhar

    2013-11-01

    Acute kidney injury occurs in 33-50% of patients with rhabdomyolysis and infections remain one of the major contributing factors. The incidence of rhabdomyolysis in non-hemorrhagic dengue virus infection is quite low and may go unnoticed, especially if the presentation is not florid. We report a case of a young male patient, sero-positive for dengue, with no hemorrhagic manifestations or hypotension, who developed rhabdomyolysis complicated by renal failure. The patient eventually needed dialysis support and later recovered fully. Clinicians need to be aware of the occurrence of rhabdomyolysis even in patients without the hemorrhagic manifestations of dengue viral infection and should employ early preventive strategies in such cases.

  2. Anterior ischemic optic neuropathy following dengue fever

    PubMed Central

    Ramakrishnan, Reshma; Shrivastava, Saurabh; Deshpande, Shrikant; Patkar, Priyanka

    2016-01-01

    Dengue fever is caused by a flavivirus. This infection is endemic in the tropics and warm temperate regions of the world. Ocular manifestations of dengue fever include subconjunctival, vitreous, and retinal haemorrhages; posterior uveitis; optic neuritis; and maculopathies, haemorrhage, and oedema. However anterior ischemic optic neuropathy is a rare presentation. Optic nerve ischemia most frequently occurs at the optic nerve head, where structural crowding of nerve fibers and reduction of the vascular supply may combine to impair perfusion to a critical degree and produce optic disc oedema. Here we present a case of anterior ischemic optic neurapathy associated with dengue fever. PMID:27843231

  3. Anterior ischemic optic neuropathy following dengue fever.

    PubMed

    Ramakrishnan, Reshma; Shrivastava, Saurabh; Deshpande, Shrikant; Patkar, Priyanka

    2016-01-01

    Dengue fever is caused by a flavivirus. This infection is endemic in the tropics and warm temperate regions of the world. Ocular manifestations of dengue fever include subconjunctival, vitreous, and retinal haemorrhages; posterior uveitis; optic neuritis; and maculopathies, haemorrhage, and oedema. However anterior ischemic optic neuropathy is a rare presentation. Optic nerve ischemia most frequently occurs at the optic nerve head, where structural crowding of nerve fibers and reduction of the vascular supply may combine to impair perfusion to a critical degree and produce optic disc oedema. Here we present a case of anterior ischemic optic neurapathy associated with dengue fever.

  4. Human Immune Responses to Dengue Viruses.

    DTIC Science & Technology

    1984-08-01

    ND-R171 381 HUR IMMUNE RESPONSES TO DENGUE VIRUSES(U) 1/1 MASSRCHUSETTS UNIY M9DICAL SCHOOL WORCESTER F R~ ENNIS RUG 94 DRMt17-2-C-2233 UNCLASSIFIED...Responses to Dengue Viruses Annual Report 0(August 1983-July 1984) Francis A. Ennis, M.D. August 1984 Supported by U.S. Army Medical Research and...3M1- NO. SON No. Frederick, Maryland 21701-5012 61102A 61102BSI0 AA 104 11. TITLE Oxkf* Samqy Oao" Human Immune Responses to Dengue Viruses 12. PERSON

  5. Pathogenesis of Dengue Vaccine Viruses in Mosquitoes.

    DTIC Science & Technology

    1981-01-01

    AD-AI30 52S PATHOGENESIS OF DENGUE VACCINE VIRUSES IN MOSQUITOES i/I (U) VALE UNIV NEW HAVEN CONN SCHOOL OF MEDICINE B J BEATY ET AL. 81 JAN 81 DAMDi...UNCLASSIFIED PATHOGENESIS OF DENGUE VACCINE VIRUSES IN MOSQUITOES Second Annual Report Barry J. Beaty, Ph.D. D T IC ; Thomas H.G. Aitken, Ph.D...REPORT NUMBER 2. GOVT ACCESSION NO. 3. RECIPIENT’S CATALOG NUMBER 4. TITLE (and Subtitle) S. TYPE OF REPORT & PERIOD COVERED PATHOMMSIS CF DENGUE

  6. Human Immune Responses to Dengue Viruses.

    DTIC Science & Technology

    1983-09-01

    A-Al?l 362 HUMAN IMMUNE RESPONSES TO DENGUE YXRUSES(U) MASSACHUSETTS UNIV MEDICAL SCHOOL NORCESTER F A ENNIS SE 83" I ?-2C23 UNCLASSI FIED SE 3IRD?8...SHEET PREVIOUS EDITION MAY BE USED UNTILDTIC FORM 70A OUMNPRESIGSETSTOCK IS EXHAUSTED.DEC 83 AD IHuman Immune Responses to Dengue Viruses Annual Report...edilon may be ued Y01dxffnUICFMCASIAZIlow f~ rolit SUMMARY The purpose of this contract is to analyse the immune responses to dengue virus infections

  7. Human Immune Responses to Dengue Viruses.

    DTIC Science & Technology

    1986-07-01

    AD-AISI 652 NUMAN IMMUNE RESPONSES TO DENGUE YIRUSES(U) / MASSACHUSETTS UNJY MEDICAL CENTER WORCESTER "A F A ENNIS 61 JUL 86 DRMDI?-82-C-2233...A S. PAGE COUNT Ie ..U rO l-9SJulyl (vw = T 21 Virus; Dengue ; Arbovirus; Immunology -- 4b he,. SAaaY~d the Interaction between the peripheral blood...lymphocytes (PBL) of non- 10m.0 deors ad dengue virus-Infected cells, which results in Interferon (113) production. AutelepMu mecyts@ or the Zpstein

  8. Human Immune Responses to Dengue Viruses.

    DTIC Science & Technology

    1986-08-01

    D-Ai8i 71S UMAN IMMUNE RESPONSES TO DENGUE VIRUSES(U) MASSACHUSETTS UNIV M DICAL CENTER WORCESTER MA F A ENNIS 81 AUG 86 DAD17-82-C-2233 UNCLSE...Classification) (U) Human Immune Responses to Dengue Viruses 12. PERSONAL AUTHOR(S) Ennis. Francis A. 13a. TYPE OF REPORT 13b. TIME COVERED 414. DATE OF...Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP06 13 Virus; Dengue ; Arbovirus; Immunology 06 03 I9% ABSTRACT

  9. Development of Dengue Vaccine, Phase 1

    DTIC Science & Technology

    1987-07-01

    AD-A260 281 AD____ CONTRACT NO: DAMD17-87-C-7061 D TIC([%ELECTE TITLE: DEVELOPMENT OF DENGUE VACCINE, PHASE I S 6 PRINCIPAL INVESTIGATOR: John M. Ivy...Phase I (12/15/86-6/15/871 J- " , : T.5 5 JNDOZG :;UMBERS Contract No. Development of Dengue Vaccine, Phase I DAMD17-87-C-7061 65502A 13P665502M802.AA...distribution unlimited Dengue virus is a mosquito borne, positive strand RNA virus responsi- ble for hundreds of thousands of illnesses annually. No

  10. Human Immune Responses to Dengue Viruses.

    DTIC Science & Technology

    1985-08-01

    t-Ril 630 HuMAN IMMUNE RESPONSES TO DENGUE VIRUSES(U) 1 - MASSACHUSETTS UNIV MEDICAL SCHOOL WORCESTER F A ENNIS 01 AUGO 95 DAMDI-2-C-2233 UNCASSIFIED...Classification) (U) Human Immune Responses to Dengue Viruses 12. PERSONAL AUTHOR(S) Ennis, Francis A. 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF...on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP06 13 Virus; Dengue ; Arbovirus; Immunology 06 13 19. ABSTRACT (Continue on

  11. Human Immune Response to Dengue Infections.

    DTIC Science & Technology

    1987-07-30

    W5l "I± H"MN IMMUNE RESPONSE TO DENGUE INFECTIONS(U) i/il MASSACHUSETTS UNIV MEDICAL CENTER NORCESTER MR1 F R ENIS 36 JUL 87 DAMD7-86-C-6200...1 U . AD HUMAN IMMUNE RESPONSE TO DENGUE INFECTIONS ANNUAL REPORT In 00 FRANCIS A. ENNIS JULY 30, 1987 Supported by U.S. ARMY MEDICAL RESEARCH...Human Immune Response to Dengue Infections 12. PERSONAL AUTHOR(S) Ennis, Francis A. 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year

  12. Pathogenesis of Dengue Vaccine Viruses in Mosquitoes.

    DTIC Science & Technology

    1982-01-01

    AD-R38 519 PATHOGENESIS OF DENGUE VACCINE VIRUSES IN MOSQUITOES i/i (U) YALE UNIV NEW HAVEN CONN SCHOOL OF MEDICINE B J BEATY ET AL. 81 JAN 82 DAMDI...NATIONAL BUREAU OF STANDARDS 1963-A i UNCLASSIFIED ":’:" AD 2 0. PATHOGENESIS OF DENGUE VACCINE VIRUSES IN MOSQUITOES Third Annual Report Barry J. Beaty...SUPPLEMENTARY NOTES 1 7 Y NORDS (rontinue on reverq , side if necessary and identify by hlock numb-) Dengue -2 S-1 vaccine, PR-159 parent; IDenque-1

  13. Temperature dependent conformational change of dengue virus.

    PubMed

    Zhang, Xinzheng; Sun, Lei; Rossmann, Michael G

    2015-06-01

    Dengue virus is the causative agent of dengue virus fever. It infects about 400 million people per year and leads to about 21,000 deaths annually. There is available neither a fully successful vaccine nor a successful drug therapy. Some dengue virus serotypes undergo a temperature dependent conformational change from a 'smooth' form at lower temperatures to a 'bumpy' form at temperatures approaching 37°C, the human body temperature. The bumpy structure is less stable and is probably an intermediate in the formation of a fusogenic virus particle. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. [Neonatal dengue in Peru: a case report].

    PubMed

    Silva Delgado, Hermann; Ruiz Ríos, Juan Carlo; Vela Barbarán, Erick Leray; Rengifo Del Aguila, Deicy; García M, María; Rodríguez Benavides, Luis; Mendoza-Ticona, Alberto

    2011-03-01

    We present the case of a full-term female newborn, whose mother died seven days postpartum from multi-organ failure due to severe dengue confirmed by NS1 antigen detection and positive IgM. The newborn did not have any complication, but at the fourth day of life she developed fever, jaundice, signs of plasma leakage, thrombocytopenia, hepatomegaly, ascitis, and others signs of systemic inflammation response syndrome. She fully recovered with supportive treatment. The RT-PCR test of a peripheral blood sample revealed a positive result for the dengue virus serotype 2, confirming the first case of neonatal dengue reported in Peru.

  15. Simultaneous Larva Migrans and Larva Currens Caused by Strongyloides stercoralis: A Case Report

    PubMed Central

    Corte, Liliam Dalla; da Silva, Mariana Vale Scribel; Souza, Paulo Ricardo Martins

    2013-01-01

    Strongyloidiasis is an infectious disease caused by the Strongyloides stercoralis larvae, which penetrate the skin, go through the lymphatic circulation, and migrate to the lungs before reaching the intestines. They mature and may cause cutaneous strongyloidiasis, known as larva currens because of the quick migratory rate of the larva. The authors describe a case in which the larvae did not follow their natural lymph route, and after penetrating into the intertriginous area, they migrated to the dermis, developing larva migrans in the early phase, and later associated with the typical lesions of larva currens. The diagnosis was confirmed by the presence of larva in the skin biopsy. PMID:23476820

  16. Bromeliad-inhabiting mosquitoes in an urban botanical garden of dengue endemic Rio de Janeiro. Are bromeliads productive habitats for the invasive vectors Aedes aegypti and Aedes albopictus?

    PubMed Central

    Mocellin, Márcio Goulart; Simões, Taynãna César; do Nascimento, Teresa Fernandes Silva; Teixeira, Maria Lucia França; Lounibos, Leon Philip; de Oliveira, Ricardo Lourenço

    2012-01-01

    Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus (0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats. PMID:20140379

  17. Survey of cyclopids (Crustacea, Copepoda) in Brazil and preliminary screening of their potential as dengue vector predators.

    PubMed

    dos Santos, L U; de Andrade, C F

    1997-06-01

    Cyclopid copepods are known to be good mosquito controllers, specially as regards the larvae of the dengue vectors Aedes aegypti and Ae. albopictus. The objective of the study was to survey the local copepod fauna and search for new strains of M. longisetus var. longisetus, comparing the potential of the samples found with the current strain ML-01 against Ae. albopictus larvae, under laboratory conditions. Eleven bodies of water in Campinas, SP, Brazil, were screened for copepods by collecting 1.5 l of water from each of then. The predatory potential of adults copepods was evaluated over 24 h, in the laboratory, for groups of 5 individuals preying upon 30 first instar Ae. albopictus larvae. The following cyclopid species were found: Metacyclops mendocinus, Tropocyclops prasinus, Eucyclops sp, Eucyclops serrulatus, Eucyclops solitarius, Eucyclops ensifer, Macrocyclops albidus var. albidus and Mesocyclops longisetus var. longisetus. The predatory potential of these copepods ranged from nil to 97.3%. A sample collected in the field containing only M. longisetus var. longisetus showed the best control efficiency with no significant difference from a three-year old laboratory culture (ML-01) of the same species evaluated for comparison. The sample with few M. albidus var. albidus was ranked in second place showing an average 25.9% efficiency. The use of copepods in trap tires as dengue vector controllers is discussed.

  18. The use of rapid dengue diagnostic tests in a routine clinical setting in a dengue-endemic area of Colombia

    PubMed Central

    Osorio, Lyda; Uribe, Marcela; Ardila, Gloria Ines; Orejuela, Yaneth; Velasco, Margarita; Bonelo, Anilza; Parra, Beatriz

    2015-01-01

    There is insufficient evidence of the usefulness of dengue diagnostic tests under routine conditions. We sought to analyse how physicians are using dengue diagnostics to inform research and development. Subjects attending 14 health institutions in an endemic area of Colombia with either a clinical diagnosis of dengue or for whom a dengue test was ordered were included in the study. Patterns of test-use are described herein. Factors associated with the ordering of dengue diagnostic tests were identified using contingency tables, nonparametric tests and logistic regression. A total of 778 subjects were diagnosed with dengue by the treating physician, of whom 386 (49.5%) were tested for dengue. Another 491 dengue tests were ordered in subjects whose primary diagnosis was not dengue. Severe dengue classification [odds ratio (OR) 2.2; 95% confidence interval (CI) 1.1-4.5], emergency consultation (OR 1.9; 95% CI 1.4-2.5) and month of the year (OR 3.1; 95% CI 1.7-5.5) were independently associated with ordering of dengue tests. Dengue tests were used both to rule in and rule out diagnosis. The latter use is not justified by the sensitivity of current rapid dengue diagnostic tests. Ordering of dengue tests appear to depend on a combination of factors, including physician and institutional preferences, as well as other patient and epidemiological factors. PMID:25993399

  19. The use of rapid dengue diagnostic tests in a routine clinical setting in a dengue-endemic area of Colombia.

    PubMed

    Osorio, Lyda; Uribe, Marcela; Ardila, Gloria Ines; Orejuela, Yaneth; Velasco, Margarita; Bonelo, Anilza; Parra, Beatriz

    2015-06-01

    There is insufficient evidence of the usefulness of dengue diagnostic tests under routine conditions. We sought to analyse how physicians are using dengue diagnostics to inform research and development. Subjects attending 14 health institutions in an endemic area of Colombia with either a clinical diagnosis of dengue or for whom a dengue test was ordered were included in the study. Patterns of test-use are described herein. Factors associated with the ordering of dengue diagnostic tests were identified using contingency tables, nonparametric tests and logistic regression. A total of 778 subjects were diagnosed with dengue by the treating physician, of whom 386 (49.5%) were tested for dengue. Another 491 dengue tests were ordered in subjects whose primary diagnosis was not dengue. Severe dengue classification [odds ratio (OR) 2.2; 95% confidence interval (CI) 1.1-4.5], emergency consultation (OR 1.9; 95% CI 1.4-2.5) and month of the year (OR 3.1; 95% CI 1.7-5.5) were independently associated with ordering of dengue tests. Dengue tests were used both to rule in and rule out diagnosis. The latter use is not justified by the sensitivity of current rapid dengue diagnostic tests. Ordering of dengue tests appear to depend on a combination of factors, including physician and institutional preferences, as well as other patient and epidemiological factors.

  20. Dengue Expansion in Africa—Not Recognized or Not Happening?

    PubMed Central

    Junghanss, Thomas; Wills, Bridget; Brady, Oliver J.; Eckerle, Isabella; Farlow, Andrew; Hay, Simon I.; McCall, Philip J.; Messina, Jane P.; Ofula, Victor; Sall, Amadou A.; Sakuntabhai, Anavaj; Velayudhan, Raman; Wint, G.R. William; Zeller, Herve; Margolis, Harold S.; Sankoh, Osman

    2014-01-01

    An expert conference on Dengue in Africa was held in Accra, Ghana, in February 2013 to consider key questions regarding the possible expansion of dengue in Africa. Four key action points were highlighted to advance our understanding of the epidemiology of dengue in Africa. First, dengue diagnostic tools must be made more widely available in the healthcare setting in Africa. Second, representative data need to be collected across Africa to uncover the true burden of dengue. Third, established networks should collaborate to produce these types of data. Fourth, policy needs to be informed so the necessary steps can be taken to provide dengue vector control and health services. PMID:25271370

  1. Dengue expansion in Africa-not recognized or not happening?

    PubMed

    Jaenisch, Thomas; Junghanss, Thomas; Wills, Bridget; Brady, Oliver J; Eckerle, Isabella; Farlow, Andrew; Hay, Simon I; McCall, Philip J; Messina, Jane P; Ofula, Victor; Sall, Amadou A; Sakuntabhai, Anavaj; Velayudhan, Raman; Wint, G R William; Zeller, Herve; Margolis, Harold S; Sankoh, Osman

    2014-10-01

    An expert conference on Dengue in Africa was held in Accra, Ghana, in February 2013 to consider key questions regarding the possible expansion of dengue in Africa. Four key action points were highlighted to advance our understanding of the epidemiology of dengue in Africa. First, dengue diagnostic tools must be made more widely available in the healthcare setting in Africa. Second, representative data need to be collected across Africa to uncover the true burden of dengue. Third, established networks should collaborate to produce these types of data. Fourth, policy needs to be informed so the necessary steps can be taken to provide dengue vector control and health services.

  2. First documented outbreak of dengue in the Peruvian Amazon region.

    PubMed

    Phillips, I; Need, J; Escamilla, J; Colán, E; Sánchez, S; Rodríguez, M; Vásquez, L; Seminario, J; Betz, T; da Rosa, A T

    1992-01-01

    This article describes a classical dengue outbreak caused by dengue serotypes 1 and 4 that occurred from March to July 1990 in the city of Iquitos and surrounding areas of Loreto Department in the Peruvian Amazon. Epidemiologic data indicate that more than 150,000 persons may have been affected in Iquitos alone. Another dengue outbreak occurred in Tarapoto, a city in the neighboring department of San Martín. Laboratory data indicate that the same dengue serotypes were involved in both outbreaks. No cases of dengue hemorrhagic fever/shock syndrome appear to have occurred. Prior to this outbreak, no indigenous dengue cases had been documented in Peru.

  3. Unusual Presentation of Dengue Fever Leading to Unnecessary Appendectomy

    PubMed Central

    Kumar, Lovekesh; Singh, Mahendra; Saxena, Ashish; Kolhe, Yuvraj; Karande, Snehal K.; Singh, Narendra; Venkatesh, P.; Meena, Rambabu

    2015-01-01

    Dengue fever is the most important arbovirus illness with an estimated incidence of 50–100 million cases per year. The common symptoms of dengue include fever, rash, malaise, nausea, vomiting, and musculoskeletal pain. Dengue fever may present as acute abdomen leading to diagnostic dilemma. The acute surgical complications of dengue fever include acute pancreatitis, acute acalculous cholecystitis, nonspecific peritonitis, and acute appendicitis. We report a case of dengue fever that mimicked acute appendicitis leading to unnecessary appendectomy. A careful history examination for dengue-related signs, and serial hemogram over the first 3-4 days of disease may prevent unnecessary appendectomy. PMID:26167314

  4. Unusual Presentation of Dengue Fever Leading to Unnecessary Appendectomy.

    PubMed

    Kumar, Lovekesh; Singh, Mahendra; Saxena, Ashish; Kolhe, Yuvraj; Karande, Snehal K; Singh, Narendra; Venkatesh, P; Meena, Rambabu

    2015-01-01

    Dengue fever is the most important arbovirus illness with an estimated incidence of 50-100 million cases per year. The common symptoms of dengue include fever, rash, malaise, nausea, vomiting, and musculoskeletal pain. Dengue fever may present as acute abdomen leading to diagnostic dilemma. The acute surgical complications of dengue fever include acute pancreatitis, acute acalculous cholecystitis, nonspecific peritonitis, and acute appendicitis. We report a case of dengue fever that mimicked acute appendicitis leading to unnecessary appendectomy. A careful history examination for dengue-related signs, and serial hemogram over the first 3-4 days of disease may prevent unnecessary appendectomy.

  5. Dengue and Chikungunya Vector Control Pocket Guide

    DTIC Science & Technology

    2012-01-27

    pupae . Examples of such items are tarps, plastic sheeting, and other materials used as...locations and to develop a control program. Survey containers both inside and outside homes. Surveillance of larvae and pupae can be...minimum of 10‐20% of habitats identified -14- container if larvae or pupae are being returned to the laboratory. Larvae: The

  6. Temephos Resistance in Aedes aegypti in Colombia Compromises Dengue Vector Control

    PubMed Central

    Grisales, Nelson; Poupardin, Rodolphe; Gomez, Santiago; Fonseca-Gonzalez, Idalyd; Ranson, Hilary; Lenhart, Audrey

    2013-01-01

    Background Control and prevention of dengue relies heavily on the application of insecticides to control dengue vector mosquitoes. In Colombia, application of the larvicide temephos to the aquatic breeding sites of Aedes aegypti is a key part of the dengue control strategy. Resistance to temephos was recently detected in the dengue-endemic city of Cucuta, leading to questions about its efficacy as a control tool. Here, we characterize the underlying mechanisms and estimate the operational impact of this resistance. Methodology/Principal Findings Larval bioassays of Ae. aegypti larvae from Cucuta determined the temephos LC50 to be 0.066 ppm (95% CI 0.06–0.074), approximately 15× higher than the value obtained from a susceptible laboratory colony. The efficacy of the field dose of temephos at killing this resistant Cucuta population was greatly reduced, with mortality rates <80% two weeks after application and <50% after 4 weeks. Neither biochemical assays nor partial sequencing of the ace-1 gene implicated target site resistance as the primary resistance mechanism. Synergism assays and microarray analysis suggested that metabolic mechanisms were most likely responsible for the temephos resistance. Interestingly, although the greatest synergism was observed with the carboxylesterase inhibitor, DEF, the primary candidate genes from the microarray analysis, and confirmed by quantitative PCR, were cytochrome P450 oxidases, notably CYP6N12, CYP6F3 and CYP6M11. Conclusions/Significance In Colombia, resistance to temephos in Ae. aegypti compromises the duration of its effect as a vector control tool. Several candidate genes potentially responsible for metabolic resistance to temephos were identified. Given the limited number of insecticides that are approved for vector control, future chemical-based control strategies should take into account the mechanisms underlying the resistance to discern which insecticides would likely lead to the greatest control efficacy while

  7. Prevalence and insecticide susceptibility of dengue vectors in the district of Batticaloa in eastern Sri Lanka.

    PubMed

    Dharshini, Sangaralingam; Vinobaba, Muthuladchumy; Jude, Pavilupillai J; Karunaratne, S H P Parakrama; Surendran, Sinnathamby N

    2011-06-01

    Unprecedented incidences of dengue have been reported in Sri Lanka in recent years. The district of Batticaloa, which was devastated by the 2004 Asian tsunami, is one of the districts affected by dengue. One option to curtail this disease is to implement appropriate vector control measures. A nine-month study was carried out within the Batticaloa Municipal Council limit from April to December 2008. Larval collections were conducted fortnightly using conventional ovitraps for nine months covering the dry and wet seasons. Ovitraps (indoor and outdoor) were placed in 15 randomly selected houses. The collected larvae were brought to the laboratory and reared under laboratory conditions. The larval forms and emerged adults were identified on the basis of reported morphological descriptions. The identified adults of 2-3 d old were exposed to common insecticides following the WHO protocol. During the study period, a total of 10,685 Aedes aegypti and Ae. albopictus mosquitoes were collected, with the former constituting 57% of the total sample. Both species were collected from indoor and outdoor ovitraps, and their prevalence was recorded throughout the study period. A seasonal shift was observed in the density, with Ae. aegypti predominating during the dry season and Ae. albopictus during the wet season. Both species were highly resistant to 4% DDT and susceptible to 0.25% permethrin. The continuous presence of potential dengue vectors may have contributed to the dengue prevalence in the district. Since both species can oviposit in indoor and outdoor ovitraps, public awareness and participation should be promoted in the vector control programme of the Ministry of Health along with continuous vector surveillance.

  8. Dengue virus in Mexican bats

    PubMed Central

    AGUILAR-SETIÉN, Á.; ROMERO-ALMARAZ, M. L.; SÁNCHEZ-HERNÁNDEZ, C.; FIGUEROA, R.; JUÁREZ-PALMA, L. P.; GARCÍA-FLORES, M. M.; VÁZQUEZ-SALINAS, C.; SALAS-ROJAS, M.; HIDALGO-MARTÍNEZ, A. C.; PIERLÉ, S. AGUILAR; GARCÍA-ESTRADA, C.; RAMOS, C.

    2008-01-01

    SUMMARY Individuals belonging to five families, 12 genera, and 19 different species of bats from dengue endemic areas in the Gulf and Pacific coasts of Mexico were examined by ELISA, RT–PCR, and for the presence of dengue virus (DV) NS1 protein. Nine individuals from four species were seropositive by ELISA: three insectivorous, Myotis nigricans (four positives/12 examined), Pteronotus parnellii (3/19), and Natalus stramineus (1/4), and one frugivorous Artibeus jamaicensis (1/35) (12·86% seroprevalence in positive species). DV serotype 2 was detected by RT–PCR in four samples from three species (all from the Gulf coast – rainy season): two frugivorous, A. jamaicensis (2/9), and Carollia brevicauda (1/2), and one insectivorous, M. nigricans (1/11). The latter was simultaneously positive for NS1 protein. DV RT–PCR positive animals were all antibody seronegative. M. nigricans showed positive individuals for all three tests. This is the first evidence suggesting the presence of DV in bats from Mexico. PMID:18325131

  9. Dengue: an update on treatment options.

    PubMed

    Chan, Candice Y Y; Ooi, Eng Eong

    2015-01-01

    Dengue is the most important mosquito-borne viral pathogen globally, with approximately 100 million cases of acute dengue annually. Infection can result in severe, life-threatening disease. Currently, there is no effective vaccine or licensed antiviral. Management is primarily supportive with fluids. Direct antiviral therapies that reduce dengue severity could be useful although these would need to inhibit all four viral serotypes effectively. This review focuses on the interventions that currently considered the gold standard in case management as well as exploratory therapies that have been studied in clinical trials. Although antiviral drug and therapeutic antibodies for dengue remain a work in progress, these studies have produced some promising results and may have the potential to be future drugs.

  10. Case Management of Dengue: Lessons Learned.

    PubMed

    Kalayanarooj, Siripen; Rothman, Alan L; Srikiatkhachorn, Anon

    2017-03-01

    The global burden of dengue and its geographic distribution have increased over the past several decades. The introduction of dengue in new areas has often been accompanied by high case-fatality rates. Drawing on the experience in managing dengue cases at the Queen Sirikit National Institute of Child Health in Bangkok, Thailand, this article provides the authors' perspectives on key clinical lessons to improve dengue-related outcomes. Parallels between this clinical experience and outcomes reported in randomized controlled trials, results of efforts to disseminate practice recommendations, and suggestions for areas for further research are also discussed. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  11. Safety Testing of Dengue-1 and Dengue-3 Seeds for Human Challenges, Unattenuated; Hepatitis A Virus, Strain HM-175

    DTIC Science & Technology

    1989-06-01

    q j. AD 00 CSAFETY TESTING OF DENGUE -1 AND DENGUE -3 SEEDS FOR HUMAN CHALLENGES, UNATTENUATED; 0HEPATITIS A VIRUS, STRAIN HM-1750 FINAL REPORT By D...TITLE (Include Scurrty Classifcation)627A 27A8JC09 (U) Safety Testing of Dengue -1 and Dengue -3 Seeds for Human Challenges, Unattenuatei; Hepatitis A...necenary and identify by block number) 06EL GR3U Dengue -1; Dengue -3; Hepatitis A; Viral seeds; Vaccine; PA-1 06 03 I 1 ABSTRACT (Continue On reverse it

  12. Safety Testing of Dengue-1 and Dengue-3 Seeds for Human Challenges, Unattenuated; Hepatitis A Virus, Strain HM175

    DTIC Science & Technology

    1988-07-01

    AD SAFETY TESTING OF DENGUE -I AND DENGUE -3 SEEDS FOR HUMAN CHALLENGES, UNATrENUATED; HEPATITIS A VIRUS, STRAIN HM175 PHASE REPOR DTICcUUS PO.CASH{ I... Dengue -1 and Dengue -3 Seeds for Human Challenges, Unattenuated; Hepatitis A Virus. -Strain HM175 12. PERSONAL AUThOR(S) Potash, Louis 13&. TYPE OF...COSATI CODES ? B. SUBJECT TERMS (C~in0iU* an LIve i ec*ty arid identify by bdocir nunme) FIELD GROUP SU-GROUP 06 13 L Dengue -1; Dengue -3; Hepatitis A

  13. Coexistence of Philodina roseola (Rotifera: Bdelloidea) with larvae of Aedes aegypti in India.

    PubMed

    Muniaraj, M; Sathish Babu, R

    2014-06-01

    The vector mosquitoes, Aedes aegypti and Aedes albopictus of dengue and Chikungunya fever are closely associated with human habitations and adapted to feed on human blood. They undergo larval and pupal development in natural and artificial freshwater collections in the urban and peri-urban environment. Although reports are available about the feeding behaviour of the thriving mosquito larvae, much information is still required to understand the successful survival of Aedes mosquitoes in small and temporary water collections. This study was undertaken to determine the co-existence and prevalence of Philodina roseola and other Bdelloid rotifers in the container habitats of Ae. aegypti mosquitoes. The investigation was conducted in 43 villages which belong to four districts in South India, affected by the epidemic of either dengue or Chikungunya fever. A total of 2093 houses and 12980 containers were examined for Aedes breeding and those containers with Aedes larvae were chosen for further investigation. The investigation showed that, the P. roseola was found associated in 502 (98.2%) containers, P. roseola along with other Philodina sp. in 126 containers (25%) and P. roseola along with other Philodina sp. and other Bdelloid rotifers found in 93 containers (19%). Since the members of the genus Philodina can survive desiccation, reproduce by parthenogenesis, can be transported by wind easily and more importantly, it can incorporate the genome of other organisms including viruses, understanding the co-existence and relationship of Philodina sp. with Aedes larvae would be helpful in the control of Aedes breeding and the control measures can be designed keeping the association of Bdelloids with Aedes in mind.

  14. Association of interleukin-2, -4 and -10 with dengue severity.

    PubMed

    Abhishek, Kumar S; Chakravarti, Anita; Baveja, C P; Kumar, Naresh; Siddiqui, Oves; Kumar, Suman

    2017-01-01

    Dengue is an arboviral disease caused by four distinct serotypes of dengue virus. The pathogenesis of dengue is not very clearly understood. Various pro- and anti-inflammatory cytokines are involved in the immune pathogenesis of dengue. Interleukin (IL)-2/IL-2 receptor interaction is supposed to play a protective role, while IL-4 acts as pro-inflammatory whereas IL-10 acts as anti-inflammatory cytokines. So far, not much information is available regarding the established role of these cytokines with dengue infection and severity. our study aimed to show the association of IL-2, -4, and -10 with severity of dengue infection. This was a cross-sectional study. The study was conducted in the year 2015; 150 blood samples from suspected dengue cases were confirmed for dengue and then with an equal number of healthy control samples were tested for cytokines levels (IL-2, -4, and -10) by ELISA. Severity of the dengue infection was determined on the basis of clinical manifestations based on the WHO criteria. for statistical analysis, SPSS version 21 (IBM, New York, United States) was used. Out of 150 samples, 56 samples came to be dengue positive. Thirty-eight (67.85%) cases were classified as nonsevere dengue and 18 (32.15%) were severe dengue. The serum levels of IL-4 and -10 were significantly raised in severe dengue cases as compared to nonsevere dengue cases. No significant association was observed between serum IL-2 levels and the severity of dengue. IL-4 and -10 levels can be used as marker of severe dengue and help in early preparedness to start the treatment in the line of severe dengue.

  15. Lung in Dengue: Computed Tomography Findings

    PubMed Central

    Rodrigues, Rosana Souza; Brum, Ana Livia Garcia; Paes, Marciano Viana; Póvoa, Tiago Fajardo; Basilio-de-Oliveira, Carlos Alberto; Marchiori, Edson; Borghi, Danielle Provençano; Ramos, Grazielle Viana; Bozza, Fernando Augusto

    2014-01-01

    Background Dengue is the most important mosquito-borne viral disease in the world. Dengue virus infection may be asymptomatic or lead to undifferentiated fever, dengue fever with or without warning signs, or severe dengue. Lower respiratory symptoms are unusual and lung-imaging data in patients with dengue are scarce. Methodology/Principal Findings To evaluate lung changes associated with dengue infection, we retrospectively analyzed 2,020 confirmed cases of dengue. Twenty-nine of these patients (11 females and 18 males aged 16–90 years) underwent chest computed tomography (CT), which yielded abnormal findings in 17 patients: 16 patients had pleural effusion (the sole finding in six patients) and 11 patients had pulmonary abnormalities. Lung parenchyma involvement ranged from subtle to moderate unilateral and bilateral abnormalities. The most common finding was ground-glass opacity in eight patients, followed by consolidation in six patients. Less common findings were airspace nodules (two patients), interlobular septal thickening (two patients), and peribronchovascular interstitial thickening (one patient). Lung histopathological findings in four fatal cases showed thickening of the alveolar septa, hemorrhage, and interstitial edema. Conclusions/Significance In this largest series involving the use of chest CT to evaluate lung involvement in patients with dengue, CT findings of lower respiratory tract involvement were uncommon. When abnormalities were present, pleural effusion was the most frequent finding and lung involvement was often mild or moderate and bilateral. Extensive lung abnormalities are infrequent even in severe disease and when present should lead physicians to consider other diagnostic possibilities. PMID:24836605

  16. Pathogenesis of Dengue Vaccine Viruses in Mosquitoes.

    DTIC Science & Technology

    1980-01-01

    1973). Sabin (1948) showed that attenuated dpngiie, passed through mosquitoes, did not revert to pathogenicity frnr man. -7- Thus even if the vaccine ...AD-A138 518 PATHOGENESIS OF DENGUE VACCINE YIRUSES IN MOSQUITOES 1/ (U) YALE UNIV NEW HAVEN CONN SCHOOL OF MEDICINE B J BEATY ET AL. 9i JAN 80 DRND7...34 ’ UNCLASSIFIED 0{) AD 0Pathogenesis of dengue vaccine viruses in mosquitoes -First Annual Report Barry I. Beaty, Ph.D. Thomas H. G

  17. Dengue vaccine development: strategies and challenges.

    PubMed

    Ramakrishnan, Lakshmy; Pillai, Madhavan Radhakrishna; Nair, Radhakrishnan R

    2015-03-01

    Infection with dengue virus may result in dengue fever or a more severe outcome, such as dengue hemorrhagic syndrome/shock. Dengue virus infection poses a threat to endemic regions for four reasons: the presence of four serotypes, each with the ability to cause a similar disease outcome, including fatality; difficulties related to vector control; the lack of specific treatment; and the nonavailability of a suitable vaccine. Vaccine development is considered challenging due to the severity of the disease observed in individuals who have acquired dengue-specific immunity, either passively or actively. Therefore, the presence of vaccine-induced immunity against a particular serotype may prime an individual to severe disease on exposure to dengue virus. Vaccine development strategies include live attenuated vaccines, chimeric, DNA-based, subunit, and inactivated vaccines. Each of the candidates is in various stages of preclinical and clinical development. Issues pertaining to selection pressures, viral interaction, and safety still need to be evaluated in order to induce a complete protective immune response against all four serotypes. This review highlights the various strategies that have been employed in vaccine development, and identifies the obstacles to producing a safe and effective vaccine.

  18. Inclusion of dengue in TDR's disease portfolio.

    PubMed

    1999-08-01

    This article reports the outcome of the informal consultation of the WHO in-house expert scientists on the proposed inclusion of dengue and tuberculosis in the Training in Tropical Diseases (TDR) portfolio to be reviewed during the 22nd session of the Joint Coordinating Board. The purpose of the meeting was to identify research gaps, pinpoint research needed, and proposed a potential agenda for TDR activities regarding dengue and dengue hemorrhagic fever (DHF). During the meeting, WHO staff presented an analysis of the global situation for dengue and an outline of WHO activities in dengue control and vaccine development. Three discussion groups proposed a list of priority subjects where TDR could initiate activities: 1) in social, economic and behavioral research; 2) in vector research; 3) in diagnosis; 4) in pathophysiology; and 5) in vaccine discovery and development. At present, the only method for controlling or preventing dengue and DHF rely on controlling the mosquito vector. Therefore, developing appropriate and efficient vector control methods, improving laboratory diagnosis and case management of patients, and developing an effective vaccine were the primary objectives of research and capability strengthening.

  19. Pediatric ischemic stroke due to dengue vasculitis.

    PubMed

    Nanda, Subrat Kumar; Jayalakshmi, Sita; Mohandas, Surath

    2014-10-01

    Dengue infection is an important arboviral infection in southeast Asia, especially in India. Neurological manifestations of dengue are increasingly recognized. We report an ischemic stroke due to dengue vasculitis in an 8-year-old child. We present a girl with a short febrile illness followed by episodic severe headache, with gradually progressive hemiparesis and visual impairment. Her brain magnetic resonance imaging revealed multiple infarctions in the anterior and posterior circulation. The magnetic resonance angiogram revealed irregular narrowing of bilateral middle cerebral arteries, right anterior cerebral artery, left posterior cerebral, and bilateral vertebral arteries suggestive of vasculitis. Her dengue serology was strongly positive for immunoglobulin M with 68.9 panbio units. The rest of the evaluation for pediatric stroke was unremarkable. She was treated with intravenous followed by oral corticosteroids and recovered totally with resolution of vasculitis on magnetic resonance angiogram over the next 3 months. This child illustrates possible immune-mediated vasculitis caused by dengue infection which is rather a rare presentation in a child who subsequently recovered well. One should consider dengue in childhood strokes in endemic regions. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Development of Peptide Vaccines in Dengue.

    PubMed

    Reginald, Kavita; Chan, Yanqi; Plebanski, Magdalena; Poh, Chit Laa

    2017-09-13

    Dengue is one of the most important arboviral infection worldwide, infecting up to 390 million people and causing 25,000 deaths annually. Although a licensed dengue vaccine is available, it is not efficacious against dengue serotypes that infect people living in South East Asia, where dengue is an endemic disease. Hence, there is an urgent need to develop an efficient dengue vaccine for this region. Data from different clinical trials indicate that a successful dengue vaccine must elicit both neutralizing antibodies and cell mediated immunity. This can be achieved by designing a multi-epitope peptide vaccine comprising B, CD8+ and CD4+ T cell epitopes. As recognition of T cell epitopes are restricted by human leukocyte antigens (HLA), T cell epitopes which are able to recognize several major HLAs will be preferentially included in the vaccine design. While peptide vaccines are safe, biocompatible and cost-effective, it is poorly immunogenic. Strategies to improve its immunogenicity by the use of long peptides, adjuvants and nanoparticle delivery mechanisms are discussed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  1. Dengue mortality in Colombia, 1985-2012.

    PubMed

    Chaparro-Narváez, Pablo; León-Quevedo, Willian; Castañeda-Orjuela, Carlos Andrés

    2016-02-11

    Dengue in Colombia is an important public health problem due to the huge economic and social costs it has caused, especially during the disease outbreaks.  To describe the behavior of dengue mortality in Colombia between 1985 and 2012.  We conducted a descriptive study. Information was obtained from mortality and population projection databases provided by the Departamento Administrativo Nacional de Estadística (DANE) for the 1985-2012 period. Mortality rates, rate ratios, and case fatality rates were estimated.  A total of 1,990 dengue deaths were registered during this period in Colombia. Dengue mortality rates presented an increasing trend with statistical significance between 1985 and 1998. Higher mortality rates were reported in men both younger than 5 years and older than 65 years. Between 1995 and 2012, category 1 to 4 municipalities reported the highest mortality rates. Case fatality rates varied during the period between 0.01% and 0.39%.  Dengue is an avoidable disease that should disappear from mortality statistics as a cause of death. The event is avoidable if the proposed activities from the Estrategia de Gestión Integrada (EGI)-Dengue are implemented and evaluated. We recommend encouraging the development of an informational culture to contribute to decision making and prioritizing resource allocation.

  2. Antioxidants in patients with dengue viral infection.

    PubMed

    Chandrasena, Lal G; Peiris, Hemantha; Kamani, J; Wanigasuriya, P; Jayaratne, Shantilal D; Wijayasiri, W A A; Wijesekara, G Udaya S

    2014-09-01

    An alteration in the oxidation/reduction (redox) status of humans infected with virus infections may contrioute to tefl pariiogeiiesin anu ciniiua1 manifestations of the disease. Alterations in redox markers begin prior to the onset of clinical symptoms, suggesting early changes in the oxidant/antioxidant balance. Early identification of redox markers may be of clinical usefulness in the management of patients with dengue virus infection. We conducted a hospital based comparative cross sectional study of 55 patients serologically confirmed to have dengue infection and 55 clinically healthy age and sex matched subjects as controls to assess oxidative stress in acute dengue virus infection. Blood samples were drawn on the fifth day after symptom onset and analyzed for Trolox equivalent antioxidant capacity (TEAC), reduced glutathione (GSH), glutathione peroxidase (GPx) and paraoxonase (PON) activity. The results showed significantly lower levels of plasma TEAC, serum PON and erythrocyte GSH and GPx activity among dengue patients than in controls. Of the antioxidants investigated, PON appeared to be the most sensitive marker of oxidative stress in dengue virus infection. Serum PON may be a potentially useful marker of oxidative stress in patients with dengue virus infection.

  3. Backward bifurcations in dengue transmission dynamics.

    PubMed

    Garba, S M; Gumel, A B; Abu Bakar, M R

    2008-09-01

    A deterministic model for the transmission dynamics of a strain of dengue disease, which allows transmission by exposed humans and mosquitoes, is developed and rigorously analysed. The model, consisting of seven mutually-exclusive compartments representing the human and vector dynamics, has a locally-asymptotically stable disease-free equilibrium (DFE) whenever a certain epidemiological threshold, known as the basic reproduction number(R(0)) is less than unity. Further, the model exhibits the phenomenon of backward bifurcation, where the stable DFE coexists with a stable endemic equilibrium. The epidemiological consequence of this phenomenon is that the classical epidemiological requirement of making R(0) less than unity is no longer sufficient, although necessary, for effectively controlling the spread of dengue in a community. The model is extended to incorporate an imperfect vaccine against the strain of dengue. Using the theory of centre manifold, the extended model is also shown to undergo backward bifurcation. In both the original and the extended models, it is shown, using Lyapunov function theory and LaSalle Invariance Principle, that the backward bifurcation phenomenon can be removed by substituting the associated standard incidence function with a mass action incidence. In other words, in addition to establishing the presence of backward bifurcation in models of dengue transmission, this study shows that the use of standard incidence in modelling dengue disease causes the backward bifurcation phenomenon of dengue disease.

  4. Dengue in Bali: Clinical characteristics and genetic diversity of circulating dengue viruses

    PubMed Central

    Yohan, Benediktus; Lestarini, Asri; Hayati, Rahma F.; Meutiawati, Febrina; Suryana, Ketut; Widarsa, Tangking; Budiyasa, Dewa G.; Budiyasa, Ngurah; Myint, Khin S. A.

    2017-01-01

    A high number of dengue cases are reported annually in Bali. Despite the endemicity, limited data on dengue is available for Bali localities. Molecular surveillance study was conducted to explore the clinical and virological characteristics of dengue patients in urban Denpasar and rural Gianyar areas in Bali during the peak season in 2015. A total of 205 adult dengue-suspected patients were recruited in a prospective cross-sectional study. Demographic and clinical information were obtained, and dengue screening was performed using NS1 and IgM/IgG ELISAs. Viral RNA was subsequently extracted from patients’ sera for serotyping using conventional RT-PCR and Simplexa Dengue real-time RT-PCR, followed by genotyping with sequencing method. We confirmed 161 patients as having dengue by NS1 and RT-PCR. Among 154 samples successfully serotyped, the DENV-3 was predominant, followed by DENV-1, DENV-2, and DENV-4. Serotype predominance was different between Denpasar and Gianyar. Genotyping results classify DENV-1 isolates into Genotype I and DENV-2 as Cosmopolitan Genotype. The classification grouped isolates into Genotype I and II for DENV-3 and DENV-4, respectively. Clinical parameters showed no relationship between infecting serotypes and severity. We observed the genetic diversity of circulating DENV isolates and their relatedness with historical data and importation to other countries. Our data highlights the role of this tourist destination as a potential source of dengue transmission in the region. PMID:28531223

  5. Behavioral Response of Aedes aegypti (Diptera: Culicidae) Larvae to Synthetic and Natural Attractants and Repellents.

    PubMed

    Gonzalez, Paula V; González Audino, Paola A; Masuh, Héctor M

    2015-11-01

    Aedes aegypti (L.) (Diptera: Culicidae) is the key vector of three important arboviral diseases: dengue, yellow fever, and chikungunya. Immature stages of this species inhabit human-made containers placed in residential landscapes. In this study, we evaluated a few compounds in a sensitive behavioral assay with Ae. aegypti larvae. The orientation of larvae to different compounds was surveyed using a performance index (PI). The PI represents the response to each odorant, where a value of +1 is indicative of full attraction and -1 represents complete repulsion. The widely used insect repellent N, N-diethyl-m-toluamide elicited a significantly negative PI, as did acetophenone and indole. A yeast extract, a known food source, elicited a significantly positive PI, as did 2-methylphenol, 1-octen-3-ol, 3-methylphenol, and fish food. On the other hand, no response was observed for the essential oil of Eucalyptus grandis x Eucalyptus camaldulensis at the concentration evaluated. Pretreatment of larvae with N-ethylmaleimide and ablation of the antennae resulted in a suppression of behavioral responses. The overall mobility of ablated larvae was indistinguishable from unablated controls, and absence of any visible locomotor dysfunction was observed. This work is a contribution to the study of the chemical ecology of disease vectors with the aim of developing more efficient tools for surveillance and control.Natural and synthetic compounds attractive to Ae. aegypti larvae should be incorporated into integrated pest management programs through the use of baited traps or by improving the efficacy of larvicides commonly used in control campaigns. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Country- and age-specific optimal allocation of dengue vaccines.

    PubMed

    Ndeffo Mbah, Martial L; Durham, David P; Medlock, Jan; Galvani, Alison P

    2014-02-07

    Several dengue vaccines are under development, and some are expected to become available imminently. Concomitant with the anticipated release of these vaccines, vaccine allocation strategies for dengue-endemic countries in Southeast Asia and Latin America are currently under development. We developed a model of dengue transmission that incorporates the age-specific distributions of dengue burden corresponding to those in Thailand and Brazil, respectively, to determine vaccine allocations that minimize the incidence of dengue hemorrhagic fever, taking into account limited availability of vaccine doses in the initial phase of production. We showed that optimal vaccine allocation strategies vary significantly with the demographic burden of dengue hemorrhagic fever. Consequently, the strategy that is optimal for one country may be sub-optimal for another country. More specifically, we showed that, during the first years following introduction of a dengue vaccine, it is optimal to target children for dengue mass vaccination in Thailand, whereas young adults should be targeted in Brazil.

  7. International Dengue Vaccine Communication and Advocacy: Challenges and Way Forward.

    PubMed

    Carvalho, Ana; Van Roy, Rebecca; Andrus, Jon

    2016-01-01

    Dengue vaccine introduction will likely occur soon. However, little has been published on international dengue vaccine communication and advocacy. More effort at the international level is required to review, unify and strategically disseminate dengue vaccine knowledge to endemic countries' decision makers and potential donors. Waiting to plan for the introduction of new vaccines until licensure may delay access in developing countries. Concerted efforts to communicate and advocate for vaccines prior to licensure are likely challenged by unknowns of the use of dengue vaccines and the disease, including uncertainties of vaccine impact, vaccine access and dengue's complex pathogenesis and epidemiology. Nevertheless, the international community has the opportunity to apply previous best practices for vaccine communication and advocacy. The following key strategies will strengthen international dengue vaccine communication and advocacy: consolidating existing coalitions under one strategic umbrella, urgently convening stakeholders to formulate the roadmap for integrated dengue prevention and control, and improving the dissemination of dengue scientific knowledge.

  8. Dengue fever among Israeli expatriates in Delhi, 2015: implications for dengue incidence in Delhi, India.

    PubMed

    Neuberger, Ami; Turgeman, Avigail; Lustig, Yaniv; Schwartz, Eli

    2016-03-01

    We present the data of 13 dengue cases diagnosed between 1 August and 15 September 2015 among 240 Israeli expatriates residing in Delhi. Attack rates were similar between adults (6/128, 4.7%) and children (7/112, 6.3%). dengue virus (DENV-2) was identified in two and DENV-1 in one dengue-seropositive sample. Another febrile patient was diagnosed with chikungunya virus infection. The reported incidence of dengue fever among people living in Delhi was lower than 0.1% as of September 2015. Based on our results, we hypothesize that the incidence of dengue fever in Delhi is grossly underestimated. © International Society of Travel Medicine, 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Transmission spectroscopy of dengue viral infection Transmission spectroscopy of dengue viral infection

    NASA Astrophysics Data System (ADS)

    Firdous, S.; Ahmed, M.; Rehman, A.; Nawaz, M.; Anwar, S.; Murtaza, S.

    2012-04-01

    We presented the rapid diagnostic test for dengue infection based on light spectrum of human blood. The transmission spectra of dengue infected whole blood samples have been recorded in ultra violet to near infrared range (400 - 800 nm) of about 30 conformed infected patients and compared to normal blood samples. Transmission spectra of dengue infected blood illustrate a strong band from 400 - 600 nm with prominant peaks at 540 and 580 nm, where is in case of normal blood below 600 nm, total absorption has been observed. These prominent peaks from 400 - 600 nm are characteristics of cells damage and dangue virus antibodies immunoglobulin G (IgG) and immunoglobulin M (IgM) produced against dengue antigen. The presented diagnostic method is non invasive, cost effective, easy and fast screening technique for dengue infected patients.

  10. Assessing spatio-temporal trend of vector breeding and dengue fever incidence in association with meteorological conditions.

    PubMed

    Malik, Afifa; Yasar, Abdullah; Tabinda, Amtul Bari; Zaheer, Ihsan Elahi; Malik, Khalida; Batool, Adeeba; Mahfooz, Yusra

    2017-04-01

    Th aim of this study is to investigate spatio-temporal trends of dengue vector breeding and epidemic (disease incidence) influenced by climatic factors. The spatio-temporal (low-, medium-, and high-intensity periods) evaluation of entomological and epidemiological investigations along with climatic factors like rainfall (RF), temperature (Tmax), relative humidity (RH), and larval indexing was conducted to develop correlations in the area of Lahore, Pakistan. The vector abundance and disease transmission trend was geo-tagged for spatial insight. The sufficient rainfall events and optimum temperature and relative humidity supported dengue vector breeding with high larval indices for water-related containers (27-37%). Among temporal analysis, the high-intensity period exponentially projected disease incidence followed by post-rainfall impacts. The high larval incidence that was observed in early high-intensity periods effected the dengue incidence. The disease incidence had a strong association with RF (r = 0.940, α = 0.01). The vector larva occurrence (r = 0.017, α = 0.05) influenced the disease incidence. Similarly, RH (r = 0.674, α = 0.05) and average Tmax (r = 0.307, α = 0.05) also induced impact on the disease incidence. In this study, the vulnerability to dengue fever highly correlates with meteorological factors during high-intensity period. It provides area-specific understanding of vector behavior, key containers, and seasonal patterns of dengue vector breeding and disease transmission which is essential for preparing an effective prevention plan against the vector.

  11. Symptomatic Dengue Disease in Five Southeast Asian Countries: Epidemiological Evidence from a Dengue Vaccine Trial

    PubMed Central

    Taurel, Anne-Frieda; Capeding, Maria Rosario; Tran, Ngoc Huu; Hadinegoro, Sri Rezeki; Chotpitayasunondh, Tawee; Chong, Chee Kheong; Wartel, T. Anh; Beucher, Sophie; Frago, Carina; Moureau, Annick; Simmerman, Mark; Laot, Thelma; L’Azou, Maïna; Bouckenooghe, Alain

    2016-01-01

    Dengue incidence has increased globally, but empirical burden estimates are scarce. Prospective methods are best-able to capture all severities of disease. CYD14 was an observer-blinded dengue vaccine study conducted in children 2–14 years of age in Indonesia, Malaysia, Thailand, the Philippines, and Vietnam. The control group received no vaccine and resembled a prospective, observational study. We calculated the rates of dengue according to different laboratory or clinical criteria to make inferences about dengue burden, and compared with rates reported in the passive surveillance systems to calculate expansion factors which describe under-reporting. Over 6,933 person-years of observation in the control group there were 319 virologically confirmed dengue cases, a crude attack rate of 4.6%/year. Of these, 92 cases (28.8%) were clinically diagnosed as dengue fever or dengue hemorrhagic fever by investigators and 227 were not, indicating that most symptomatic disease fails to satisfy existing case definitions. When examining different case definitions, there was an inverse relationship between clinical severity and observed incidence rates. CYD14’s active surveillance system captured a greater proportion of symptomatic dengue than national passive surveillance systems, giving rise to expansion factors ranging from 0.5 to 31.7. This analysis showed substantial, unpredictable and variable under-reporting of symptomatic dengue, even within a controlled clinical trial environment, and emphasizes that burden estimates are highly sensitive to case definitions. These data will assist in generating disease burden estimates and have important policy implications when considering the introduction and health economics of dengue prevention and control interventions. PMID:27532617

  12. Symptomatic Dengue Disease in Five Southeast Asian Countries: Epidemiological Evidence from a Dengue Vaccine Trial.

    PubMed

    Nealon, Joshua; Taurel, Anne-Frieda; Capeding, Maria Rosario; Tran, Ngoc Huu; Hadinegoro, Sri Rezeki; Chotpitayasunondh, Tawee; Chong, Chee Kheong; Wartel, T Anh; Beucher, Sophie; Frago, Carina; Moureau, Annick; Simmerman, Mark; Laot, Thelma; L'Azou, Maïna; Bouckenooghe, Alain

    2016-08-01

    Dengue incidence has increased globally, but empirical burden estimates are scarce. Prospective methods are best-able to capture all severities of disease. CYD14 was an observer-blinded dengue vaccine study conducted in children 2-14 years of age in Indonesia, Malaysia, Thailand, the Philippines, and Vietnam. The control group received no vaccine and resembled a prospective, observational study. We calculated the rates of dengue according to different laboratory or clinical criteria to make inferences about dengue burden, and compared with rates reported in the passive surveillance systems to calculate expansion factors which describe under-reporting. Over 6,933 person-years of observation in the control group there were 319 virologically confirmed dengue cases, a crude attack rate of 4.6%/year. Of these, 92 cases (28.8%) were clinically diagnosed as dengue fever or dengue hemorrhagic fever by investigators and 227 were not, indicating that most symptomatic disease fails to satisfy existing case definitions. When examining different case definitions, there was an inverse relationship between clinical severity and observed incidence rates. CYD14's active surveillance system captured a greater proportion of symptomatic dengue than national passive surveillance systems, giving rise to expansion factors ranging from 0.5 to 31.7. This analysis showed substantial, unpredictable and variable under-reporting of symptomatic dengue, even within a controlled clinical trial environment, and emphasizes that burden estimates are highly sensitive to case definitions. These data will assist in generating disease burden estimates and have important policy implications when considering the introduction and health economics of dengue prevention and control interventions.

  13. Dengue specific immunoglobulins M, A, and E in primary and secondary dengue 4 infected Salvadorian children.

    PubMed

    Vazquez, Susana; Lozano, Celina; Perez, Ana Beatriz; Castellanos, Yinet; Ruiz, Didye; Calzada, Naifi; Guzmán, Maria Guadalupe

    2014-09-01

    El Salvador is a Central American country that has been affected by several dengue outbreaks. This study investigated the levels of IgM, IgA, and IgE anti-dengue antibodies in serum samples from children in El Salvador, with a clinical and serological diagnosis of dengue infection during the dengue 4 outbreak in 2002-2003. Seventy one serum samples were tested by ELISA and cases were classified in three groups: 13 primary dengue fever (PDF), 21 secondary dengue fever (SDF), and 37 secondary dengue hemorrhagic fever (SDHF). Also, the specificity of anti-dengue IgM for the different serotypes was tested. No significant differences in the IgM response were found between PDF and SDF, but these were detected between PDF and SDHF (P = 0.0053) and between SDF and SDHF (P = 0.0003). The IgA and IgE values showed a statistically significant difference between primary and secondary groups. The highest positivity percentage of IgA was between 95% (SDF) and 100% (SDHF) towards day 7 of onset of fever. All secondary cases were positive for IgE antibodies. The specificity of IgM was determined for DENV-4 virus in primary and secondary DF groups. This is the first study on dengue cases in Salvadorian children related to the immune response of different immunoglobulins to the type of infection and the clinical picture. Further prospective studies are needed to define if the pattern of immunoglobulins can determine early dengue infection and/or severity. © 2013 Wiley Periodicals, Inc.

  14. Dengue in the Americas and Southeast Asia: do they differ?

    PubMed

    Halstead, Scott B

    2006-12-01

    The populations of Southeast Asia (SE Asia) and tropical America are similar, and all four dengue viruses of Asian origin are endemic in both regions. Yet, during comparable 5-year periods, SE Asia experienced 1.16 million cases of dengue hemorrhagic fever (DHF), principally in children, whereas in the Americas there were 2.8 million dengue fever (DF) cases, principally in adults, and only 65,000 DHF cases. This review aims to explain these regional differences. In SE Asia, World War II amplified Aedes aegypti populations and the spread of dengue viruses. In the Americas, efforts to eradicate A. aegypti in the 1940s and 1950s contained dengue epidemics mainly to the Caribbean Basin. Cuba escaped infections with the American genotype dengue-2 and an Asian dengue-3 endemic in the 1960s and 1970s. Successive infections with dengue-1 and an Asian genotype dengue-2 resulted in the 1981 DHF epidemic. When this dengue-2 virus was introduced in other Caribbean countries, it encountered populations highly immune to the American genotype dengue-2. During the 1980s and 1990s, rapidly expanding populations of A. aegypti in Brazil permitted successive epidemics of dengue-1, -2, and -3. These exposures, however, resulted mainly in DF, with surprisingly few cases of DHF. The absence of high rates of severe dengue disease in Brazil, as elsewhere in the Americas, may be partly explained by the widespread prevalence of human dengue resistance genes. Understanding the nature and distribution of these genes holds promise for containing severe dengue. Future research on dengue infections should emphasize population-based designs.

  15. Superensemble forecasts of dengue outbreaks

    PubMed Central

    Kandula, Sasikiran; Shaman, Jeffrey

    2016-01-01

    In recent years, a number of systems capable of predicting future infectious disease incidence have been developed. As more of these systems are operationalized, it is important that the forecasts generated by these different approaches be formally reconciled so that individual forecast error and bias are reduced. Here we present a first example of such multi-system, or superensemble, forecast. We develop three distinct systems for predicting dengue, which are applied retrospectively to forecast outbreak characteristics in San Juan, Puerto Rico. We then use Bayesian averaging methods to combine the predictions from these systems and create superensemble forecasts. We demonstrate that on average, the superensemble approach produces more accurate forecasts than those made from any of the individual forecasting systems. PMID:27733698

  16. Unusual Presentation of Dengue Fever

    PubMed Central

    Aslam, Moaz; Aleem, Numra A.; Zahid, Mohammad F.; Rahman, Arshalooz J.

    2016-01-01

    Dengue fever (DF) is an acute febrile illness that follows a self-limiting course. However, some patients suffer from complications, including myocarditis, due to the involvement of other organs. A child presented at the Aga Khan University Hospital in Karachi, Pakistan, in June 2013 with a high-grade fever, malaise and epigastric pain radiating to the chest. Positive DF antigen and immunoglobulin M assays confirmed the diagnosis of DF. Persistent bradycardia with low blood pressure led to further cardiac investigations which showed a decreased ejection fraction and raised serum cardiac enzymes, indicating myocardial damage. With supportive care and use of inotropes, the spontaneous normalisation of cardiac enzyme levels and ejection fraction was observed. The child was discharged five days after admission. This case highlights the importance of identifying myocarditis in DF patients suffering from cardiac symptoms that are not explained by other potential aetiologies. Awareness, early suspicion and supportive care are essential to ensure favourable outcomes. PMID:26909198

  17. Estimating dengue vector abundance in the wet and dry season: implications for targeted vector control in urban and peri-urban Asia

    PubMed Central

    Wai, Khin Thet; Arunachalam, Natarajan; Tana, Susilowati; Espino, Fe; Kittayapong, Pattamaporn; Abeyewickreme, W; Hapangama, Dilini; Tyagi, Brij Kishore; Htun, Pe Than; Koyadun, Surachart; Kroeger, Axel; Sommerfeld, Johannes; Petzold, Max

    2012-01-01

    Background Research has shown that the classical Stegomyia indices (or “larval indices”) of the dengue vector Aedes aegypti reflect the absence or presence of the vector but do not provide accurate measures of adult mosquito density. In contrast, pupal indices as collected in pupal productivity surveys are a much better proxy indicator for adult vector abundance. However, it is unknown when it is most optimal to conduct pupal productivity surveys, in the wet or in the dry season or in both, to inform control services about the most productive water container types and if this pattern varies among different ecological settings. Methods A multi-country study in randomly selected twelve to twenty urban and peri-urban neighborhoods (“clusters”) of six Asian countries, in which all water holding containers were examined for larvae and pupae of Aedes aegypti during the dry season and the wet season and their productivity was characterized by water container types. In addition, meteorological data and information on reported dengue cases were collected. Findings The study reconfirmed the association between rainfall and dengue cases (“dengue season”) and underlined the importance of determining through pupal productivity surveys the “most productive containers types”, responsible for the majority (>70%) of adult dengue vectors. The variety of productive container types was greater during the wet than during the dry season, but included practically all container types productive in the dry season. Container types producing pupae were usually different from those infested by larvae indicating that containers with larval infestations do not necessarily foster pupal development and thus the production of adult Aedes mosquitoes. Conclusion Pupal productivity surveys conducted during the wet season will identify almost all of the most productive container types for both the dry and wet seasons and will therefore facilitate cost-effective targeted interventions

  18. Describing dengue epidemics: Insights from simple mechanistic models

    NASA Astrophysics Data System (ADS)

    Aguiar, Maíra; Stollenwerk, Nico; Kooi, Bob W.

    2012-09-01

    We present a set of nested models to be applied to dengue fever epidemiology. We perform a qualitative study in order to show how much complexity we really need to add into epidemiological models to be able to describe the fluctuations observed in empirical dengue hemorrhagic fever incidence data offering a promising perspective on inference of parameter values from dengue case notifications.

  19. Dengue Virus 1 Outbreak in Buenos Aires, Argentina, 2016.

    PubMed

    Tittarelli, Estefanía; Lusso, Silvina B; Goya, Stephanie; Rojo, Gabriel L; Natale, Mónica I; Viegas, Mariana; Mistchenko, Alicia S; Valinotto, Laura E

    2017-10-01

    The largest outbreak of dengue in Buenos Aires, Argentina, occurred during 2016. Phylogenetic, phylodynamic, and phylogeographic analyses of 82 samples from dengue patients revealed co-circulation of 2 genotype V dengue virus lineages, suggesting that this virus has become endemic to the Buenos Aires metropolitan area.

  20. Fatal Fulminant Hepatic Failure in a Diabetic with Primary Dengue

    PubMed Central

    Viswanathan, Stalin; Iqbal, Nayyar; Anemon, P. Philip; Kumar, G. Shyam

    2010-01-01

    We report a 49-year-old diabetic with dengue hemorrhagic fever who developed fulminant hepatitis, severe coagulopathy, shock, and refractory metabolic acidosis and died on the eighth day of illness. This is the only second report of an adult with fatal fulminant hepatic failure due to dengue, and the first case arising from a primary dengue infection. PMID:21234316

  1. Management of dengue in Australian travellers: a retrospective multicentre analysis.

    PubMed

    Tai, Alex Yc; McGuinness, Sarah L; Robosa, Roselle; Turner, David; Huang, G Khai Lin; Leder, Karin; Korman, Tony M; Thevarajan, Irani; Stewardson, Andrew J; Padiglione, Alexander A; Johnson, Douglas F

    2017-04-17

    To describe the epidemiology, clinical and laboratory features and outcomes of dengue in returned Australian travellers, applying the revised WHO dengue classification (2009) to this population. Retrospective case series analysis of confirmed dengue cases hospitalised at one of four Australian tertiary hospitals, January 2012 - May 2015. Clinical features, laboratory findings and outcomes of patients with dengue; dengue classification according to 2009 WHO guidelines. 208 hospitalised patients (median age, 32 years; range, 4-76 years) were included in the study. Dengue was most frequently acquired in Indonesia (94 patients, 45%) and Thailand (40, 19%). The most common clinical features were fever (98% of patients) and headache (76%). 84 patients (40%) met the WHO criteria for dengue with warning signs, and one the criteria for severe dengue; the most common warning signs were mucosal bleeding (44 patients, 21%) and abdominal pain (43, 21%). Leukopenia (176 patients, 85%), thrombocytopenia (133, 64%), and elevated liver enzyme levels (154, 76%) were the most common laboratory findings. 46 patients (22%) had serological evidence of previous exposure to dengue virus. WHO guidelines were documented as a management benchmark in ten cases (5%); 46 patients (22%) received non-steroidal anti-inflammatory drugs (NSAIDs). A significant proportion of returning Australian travellers hospitalised for dengue have unrecognised warning signs of severe disease. Many received NSAIDs, which can increase the risk of haemorrhage in dengue. As travel to Asia from Australia continues to increase, it is vital for averting serious outcomes that clinicians can recognise and manage dengue.

  2. Reemergence and Autochthonous Transmission of Dengue Virus, Eastern China, 2014.

    PubMed

    Wang, Wen; Yu, Bin; Lin, Xian-Dan; Kong, De-Guang; Wang, Jian; Tian, Jun-Hua; Li, Ming-Hui; Holmes, Edward C; Zhang, Yong-Zhen

    2015-09-01

    In 2014, 20 dengue cases were reported in the cities of Wenzhou (5 cases) and Wuhan (15 cases), China, where dengue has rarely been reported. Dengue virus 1 was detected in 4 patients. Although most of these cases were likely imported, epidemiologic analysis provided evidence for autochthonous transmission.

  3. Seroprevalence of acute dengue in a Malaysian tertiary medical centre

    PubMed Central

    Ding, Chuan Hun; Rashid, Zetti Zainol; Rahman, Md. Mostafizur; Khang, NanFeng; Low, Wan Ngor; Hussin, Nurabrar; Marzuki, Melissa Iqlima; Jaafar, Alyaa Nadhira; Roslan, Nurul Ain’ Nabilla; Chandrasekaran, Terukumar

    2016-01-01

    Objectives: The aims of this study were to determine the seroprevalence of acute dengue in Universiti Kebangsaan Malaysia (UKM) Medical Centre and its correlation with selected haematological and biochemical parameters. Methods: This cross-sectional study was conducted from January to June 2015. A patient was serologically diagnosed with acute dengue if the dengue virus IgG, IgM or NS-1 antigen was reactive. Results: Out of 1,774 patients suspected to have acute dengue, 1,153 were serologically diagnosed with the infection, resulting in a seroprevalence of 64.9%. Dengue-positive patients had a lower mean platelet count (89 × 109/L) compared to the dengue-negative patients (171 × 109/L) (p<0.0001). The mean total white cell count was also lower in the dengue-positive cases (4.7 × 109/L vs. 7.2 × 109/L; p<0.0001). The mean haematocrit was higher in patients with acute dengue (42.5% vs. 40.0%; p<0.0001). Likewise, the serum alanine transaminase level was also higher in patients with acute dengue (108 U/L vs. 54 U/L; p<0.0001). Conclusions: Dengue is very prevalent in UKM Medical Centre as most patients suspected to have acute dengue had serological evidence of the infection. The platelet count was the single most likely parameter to be abnormal (i.e. low) in patients with acute dengue. PMID:27182269

  4. Distribution of Mosquito Larvae on Kosrae Island, Kosrae State, the Federated States of Micronesia

    PubMed Central

    Noda, Shinichi; Yamamoto, Sota; Toma, Takako; Taulung, Livinson

    2013-01-01

    Surveys of mosquito larvae were carried out in six areas of Kosrae Island, Kosrae State, the Federated States of Micronesia in December 2009 and June 2012. A total of 962 larvae of six species were collected from 106 natural and artificial habitats. They were identified as Aedes aegypti, Ae. albopictus, Ae. marshallensis, Culex quinquefasciatus, Cx. annulirostris, and Cx. kusaiensis. This is the first report from Kosrae Island for three of these species—Ae. marshallensis, Cx. quinquefasciatus, and Cx. annulirostris. The most abundant species was Ae. albopictus, followed by Ae. marshallensis, and these two species were found in all areas. Relatively large numbers of Cx. quinquefasciatus and Cx. kusaiensis were found in five areas. Fewer Cx. annulirostris were found, and only in three areas. Aedes aegypti larvae were collected from a single habitat at Tafunsak in 2009. To prevent the outbreak of dengue fever, environmental management should focus on the destruction, alteration, disposal and recycling of containers that produce larger numbers of adult Aedes mosquitoes. PMID:24478593

  5. Distribution of mosquito larvae on kosrae island, kosrae state, the federated States of micronesia.

    PubMed

    Noda, Shinichi; Yamamoto, Sota; Toma, Takako; Taulung, Livinson

    2013-12-01

    Surveys of mosquito larvae were carried out in six areas of Kosrae Island, Kosrae State, the Federated States of Micronesia in December 2009 and June 2012. A total of 962 larvae of six species were collected from 106 natural and artificial habitats. They were identified as Aedes aegypti, Ae. albopictus, Ae. marshallensis, Culex quinquefasciatus, Cx. annulirostris, and Cx. kusaiensis. This is the first report from Kosrae Island for three of these species-Ae. marshallensis, Cx. quinquefasciatus, and Cx. annulirostris. The most abundant species was Ae. albopictus, followed by Ae. marshallensis, and these two species were found in all areas. Relatively large numbers of Cx. quinquefasciatus and Cx. kusaiensis were found in five areas. Fewer Cx. annulirostris were found, and only in three areas. Aedes aegypti larvae were collected from a single habitat at Tafunsak in 2009. To prevent the outbreak of dengue fever, environmental management should focus on the destruction, alteration, disposal and recycling of containers that produce larger numbers of adult Aedes mosquitoes.

  6. Factors influencing the seasonal abundance of Aedes (Stegomyia) aegypti and the control strategy of dengue and dengue haemorrhagic fever in Thanlyin Township, Yangon City, Myanmar.

    PubMed

    Oo, T T; Storch, V; Madon, M B; Becker, N

    2011-08-01

    From June 2006 to May 2007, mosquito surveys were conducted in Thanlyin Township, Yangon City, Myanmar, to determine factors influencing the abundance of Aedes aegypti (Stegomyia aegypti) during the rainy season. Both the biological and environmental factors were included in this study. Increase in the hatchability of egg, larval survival rate, the shortened larval life-span and increased pupation rates supplemented by rainfall (i.e. continuous flooding of the containers, stimulate the continuous hatching of eggs) were observed for correlation with the increase in population density of Ae. aegypti during the rainy season in the study area. Control strategy of Ae. aegypti to analyze the infestation in the community (study area) with larval Ae. aegypti, integrated management measures including health education, attitudes and practices regarding dengue and dengue haemorrhagic fever, transmission of the disease and possible preventive measures, reduction of breeding sites and testing the efficacy of Bacillus thuringiensis israelensis (B.t.i.) with respect to the reduction level of Ae. aegypti larvae in breeding sources, were taken into consideration.

  7. Differential proteomic analysis of virus-enriched fractions obtained from plasma pools of patients with dengue fever or severe dengue.

    PubMed

    Fragnoud, Romain; Flamand, Marie; Reynier, Frederic; Buchy, Philippe; Duong, Vasna; Pachot, Alexandre; Paranhos-Baccala, Glaucia; Bedin, Frederic

    2015-11-14

    Dengue is the most widespread mosquito-borne viral disease of public health concern. In some patients, endothelial cell and platelet dysfunction lead to life-threatening hemorrhagic dengue fever or dengue shock syndrome. Prognostication of disease severity is urgently required to improve patient management. The pathogenesis of severe dengue has not been fully elucidated, and the role of host proteins associated with viral particles has received little exploration. The proteomes of virion-enriched fractions purified from plasma pools of patients with dengue fever or severe dengue were compared. Virions were purified by ultracentrifugation combined with a water-insoluble polyelectrolyte-based technique. Following in-gel hydrolysis, peptides were analyzed by nano-liquid chromatography coupled to ion trap mass spectrometry and identified using data libraries. Both dengue fever and severe dengue viral-enriched fractions contained identifiable viral envelope proteins and host cellular proteins. Canonical pathway analysis revealed the identified host proteins are mainly involved in the coagulation cascade, complement pathway or acute phase response signaling pathway. Some host proteins were over- or under-represented in plasma from patients with severe dengue compared to patients with dengue fever. ELISAs were used to validate differential expression of a selection of identified host proteins in individual plasma samples of patients with dengue fever compared to patients with severe dengue. Among 22 host proteins tested, two could differentiate between dengue fever and severe dengue in two independent cohorts (olfactomedin-4: area under the curve (AUC), 0.958; and platelet factor-4: AUC, 0.836). A novel technique of virion-enrichment from plasma has allowed to identify two host proteins that have prognostic value for classifying patients with acute dengue who are more likely to develop a severe dengue. The impact of these host proteins on pathogenicity and disease outcome

  8. Breeding Sites of Aedes aegypti: Potential Dengue Vectors in Dire Dawa, East Ethiopia

    PubMed Central

    Getachew, Dejene; Tekie, Habte; Gebre-Michael, Teshome; Balkew, Meshesha; Mesfin, Akalu

    2015-01-01

    Background and Objectives. Entomological survey was carried out from May-June to September-October 2014 to investigate the presence of dengue vectors in discarded tires and artificial water containers in houses and peridomestic areas. Methods. A cross-sectional immature stage survey was done indoors and outdoors in 301 houses. Mosquito larval sampling was conducted using pipette or dipper depending on container types. Larvae were identified morphologically and larval indices were also calculated. Results. A total of 750 containers were inspected, and of these 405 were positive for mosquito larvae. A total of 1,873 larvae were collected and morphologically identified as Aedes aegypti (n = 1580: 84.4%) and Culex (n = 293: 15.6%). The larval indices, house index, container index, and breteau index, varied from 33.3 to 86.2, from 23.2 to 73.9, and from 56.5 to 188.9, respectively. Conclusion. Aedes aegypti is breeding in a wide range of artificial containers. To control these mosquitoes, the integration of different methods should be taken into consideration. PMID:26435712

  9. Awareness of dengue and practice of dengue control among the semi-urban community: a cross sectional survey.

    PubMed

    Naing, Cho; Ren, Wong Yih; Man, Chan Yuk; Fern, Koh Pei; Qiqi, Chua; Ning, Choo Ning; Ee, Clarice Wong Syun

    2011-12-01

    Primary prevention is the most effective measure in dengue prevention and control. The objectives were (i) to determine the level of knowledge and practice of dengue control amongst the study community, and (ii) to explore the factors affecting practice of dengue control in the study area. A cross-sectional study was conducted in a semi-urban Town of Malaysia, using a structured questionnaire covering sociodemography, knowledge related to dengue, knowledge related to Aedes mosquito and preventive measures against the disease. For comparison of survey responses, chi-square test was applied for categorical data. To explore the factors affecting the practice of dengue control, a linear regression model was introduced. Almost all of the respondents (95%) had heard about dengue. Overall, misconceptions of dengue transmission were identified and the practice of dengue control in the study population was insufficient. About half (50.5%) had misconceptions that Aedes can breed in dirty water and the preferred biting time is dusk or sunset (45.6%). Only 44.5% of the households surveyed had covered their water containers properly. Significant associations were found between knowledge scores of dengue and age (P = 0.001), education level (P = 0.001), marital status (P = 0.012), and occupation (P = 0.007). In regression analysis, only the knowledge of dengue was significantly and positively associated with practice on dengue control. A future study with larger samples and more variables to assess the knowledge, attitudes and practices of dengue control is recommended.

  10. Epidemiology of dengue: past, present and future prospects

    PubMed Central

    Murray, Natasha Evelyn Anne; Quam, Mikkel B; Wilder-Smith, Annelies

    2013-01-01

    Dengue is currently regarded globally as the most important mosquito-borne viral disease. A history of symptoms compatible with dengue can be traced back to the Chin Dynasty of 265–420 AD. The virus and its vectors have now become widely distributed throughout tropical and subtropical regions of the world, particularly over the last half-century. Significant geographic expansion has been coupled with rapid increases in incident cases, epidemics, and hyperendemicity, leading to the more severe forms of dengue. Transmission of dengue is now present in every World Health Organization (WHO) region of the world and more than 125 countries are known to be dengue endemic. The true impact of dengue globally is difficult to ascertain due to factors such as inadequate disease surveillance, misdiagnosis, and low levels of reporting. Currently available data likely grossly underestimates the social, economic, and disease burden. Estimates of the global incidence of dengue infections per year have ranged between 50 million and 200 million; however, recent estimates using cartographic approaches suggest this number is closer to almost 400 million. The expansion of dengue is expected to increase due to factors such as the modern dynamics of climate change, globalization, travel, trade, socioeconomics, settlement and also viral evolution. No vaccine or specific antiviral therapy currently exists to address the growing threat of dengue. Prompt case detection and appropriate clinical management can reduce the mortality from severe dengue. Effective vector control is the mainstay of dengue prevention and control. Surveillance and improved reporting of dengue cases is also essential to gauge the true global situation as indicated in the objectives of the WHO Global Strategy for Dengue Prevention and Control, 2012–2020. More accurate data will inform the prioritization of research, health policy, and financial resources toward reducing this poorly controlled disease. The objective

  11. Dengue in an area of the Colombian Caribbean

    PubMed Central

    Rodríguez-Barreto, Heidi; Mattar-Velilla, Salim

    2015-01-01

    Background: In Colombia, dengue is an endemic disease and the four serotypes have been reported. Objective: To describe the frequency and severity of dengue in an area of the Colombian Caribbean (Department of Cordoba) Methods: A retrospective study was conducted. Two data sources were analysed: The database from the Direction of Health in Córdoba, and clinical registers of patients diagnosed with haemorrhagic fevers and fevers of unknown origin in reference hospitals. Results: The mean incidence of dengue between 2003-2010 was 36.5 cases/105 inhabitants (CI95%: 34.3-37.5) and adjusted for sub-reporting, could be between 178.5 and 521.6. The mean incidence of severe dengue was 4.7 cases/105 inhabitants (CI95%: 4.3-5.0). Mean mortality rate due to dengue was 0.3 cases/105 inhabitants. The fatality rate was below 1%. The mean total leukocyte count in patients with dengue was 6,181 mm3 (CI95%: 5,973-6,389) and with severe Dengue was 4,729 mm3 (CI95%: 4,220-5,238). The average platelet count in patients with Dengue was 118,793/mm3 (CI95%: 107,255-130,331) and in patients with Severe Dengue 77,655 (CI95%: 59,640-95,670). Both differences were statistically significant (p <0.05). The frequency of laboratories test per patient in patients with Dengue and severe Dengue were different. Conclusion: The department of Cordoba is a highly endemic zone of Dengue and severe Dengue in the Colombian Caribbean. Moreover, the results show significant differences between dengue and severe dengue so much in tests as in frequency of use of healthcare services. PMID:26019378

  12. Biology of Paenibacillus larvae, a deadly pathogen of honey bee larvae.

    PubMed

    Ebeling, Julia; Knispel, Henriette; Hertlein, Gillian; Fünfhaus, Anne; Genersch, Elke

    2016-09-01

    The gram-positive bacterium Paenibacillus larvae is the etiological agent of American Foulbrood of honey bees, a notifiable disease in many countries. Hence, P. larvae can be considered as an entomopathogen of considerable relevance in veterinary medicine. P. larvae is a highly specialized pathogen with only one established host, the honey bee larva. No other natural environment supporting germination and proliferation of P. larvae is known. Over the last decade, tremendous progress in the understanding of P. larvae and its interactions with honey bee larvae at a molecular level has been made. In this review, we will present the recent highlights and developments in P. larvae research and discuss the impact of some of the findings in a broader context to demonstrate what we can learn from studying "exotic" pathogens.

  13. Analysis of the Optimal Vaccination Age for Dengue in Brazil with a Tetravalent Dengue Vaccine.

    PubMed

    Maier, Sandra B; Huang, Xiao; Massad, Eduardo; Amaku, Marcos; Burattini, Marcelo N; Greenhalgh, David

    2017-09-18

    In this paper we study a mathematical model to analyse the optimal vaccination age against Dengue in Brazil. Data from Brazil are used to estimate the basic reproduction numbers for each of the four Dengue serotypes and then the optimal vaccination age is calculated using a method due to Hethcote [1]. The vaccine has different efficacies against each serotype. Vaccination that is too early is ineffective as individuals are protected by maternal antibodies but leaving vaccination until later may allow the disease to spread. First of all the optimal vaccination ages are calculated where there is just one serotype in circulation and then when there are multiple serotypes. The calculations are done using data both assuming constant vaccine efficacy and age-dependent vaccine efficacy against a given serotype. The multiple serotype calculations are repeated assuming that the first infection is a risky infection and that it is not (to model Dengue Antibody Enhancement). The calculations are then repeated when any third or fourth Dengue infections are asymptomatic, so that two Dengue infections with different serotypes provide effective permanent immunity. The calculations are also repeated when the age-dependent risk function (fitted to Brazilian data) is hospitalisation from Dengue and when it is mortality due to Dengue. We find a wide variety of optimal vaccination ages depending on both the serotypes in circulation and the assumptions of the model. Copyright © 2017. Published by Elsevier Inc.

  14. Single stimulus learning in zebrafish larvae

    PubMed Central

    O’Neale, Ashley; Ellis, Joseph; Creton, Robbert; Colwill, Ruth M.

    2014-01-01

    Learning about a moving visual stimulus was examined in zebrafish larvae using an automated imaging system and a t1-t2 design. In three experiments, zebrafish larvae were exposed to one of two inputs at t1 (either a gray bouncing disk or an identical but stationary disk) followed by a common test at t2 (the gray bouncing disk). Using 7 days post-fertilization (dpf) larvae and 12 stimulus exposures, Experiment 1 established that these different treatments produced differential responding to the moving disk during testing. Larvae familiar with the moving test stimulus were significantly less likely to be still in its presence than larvae that had been exposed to the identical but stationary stimulus. Experiment 2 confirmed this result in 7 dpf larvae and extended the finding to 5 and 6 dpf larvae. Experiment 3 found differential responding to the moving test stimulus with 4 or 8 stimulus exposures but not with just one exposure in 7 dpf larvae. These results provide evidence for learning in very young zebrafish larvae. The merits and challenges of the t1-t2 framework to study learning are discussed. PMID:24012906

  15. Characteristics of and factors associated with dengue vector breeding sites in the City of Colombo, Sri Lanka

    PubMed Central

    Kusumawathie, Pad; Palihawadana, Paba; Janaki, Sakoo; Wijemuni, Ruwan; Wilder-Smith, Annelies; Tissera, Hasitha A.

    2016-01-01

    Introduction Dengue has emerged as a major public health problem in Sri Lanka. Vector control at community level is a frequent and widespread strategy for dengue control. The aim of the study was to assess Aedes mosquito breeding sites and the prevention practices of community members in a heavily urbanized part of Colombo. Methods A cross-sectional entomological survey was conducted from April to June 2013 in 1469 premises located in a subdistrict of the City of Colombo. Types of breeding sites and, where found, their infestation with larvae or pupae were recorded. Furthermore, a questionnaire was administered to the occupants of these premises to record current practices of dengue vector control. Results The surveyed premises consisted of 1341 residential premises and 110 non-residential premises (11 schools, 99 work or public sites), 5 open lands, and 13 non-specified. In these 1469 premises, 15447 potential breeding sites suitable to host larvae of pupae were found; of these sites18.0% contained water. Among the 2775 potential breeding sites that contained water, 452 (16.3%) were positive for larvae and/or pupae. Schools were associated with the proportionally highest number of breeding sites; 85 out of 133 (63.9%) breeding sites were positive for larvae and/or pupae in schools compared with 338 out of 2288 (14.8%) in residential premises. The odds ratio (OR) for schools and work or public sites for being infested with larvae and/or pupae was 2.77 (95% CI 1.58, 4.86), when compared to residential premises. Occupants of 80.8% of the residential premises, 54.5% of the schools and 67.7% of the work or public sites reported using preventive measures. The main prevention practices were coverage of containers and elimination of mosquito breeding places. Occupants of residential premises were much more likely to practice preventive measures than were those of non-residential premises (OR 2.23; 1.49, 3.36). Conclusion Schools and working sites were associated with the

  16. Characteristics of and factors associated with dengue vector breeding sites in the City of Colombo, Sri Lanka.

    PubMed

    Louis, Valérie R; Montenegro Quiñonez, Carlos Alberto; Kusumawathie, Pad; Palihawadana, Paba; Janaki, Sakoo; Tozan, Yesim; Wijemuni, Ruwan; Wilder-Smith, Annelies; Tissera, Hasitha A

    2016-03-01

    Dengue has emerged as a major public health problem in Sri Lanka. Vector control at community level is a frequent and widespread strategy for dengue control. The aim of the study was to assess Aedes mosquito breeding sites and the prevention practices of community members in a heavily urbanized part of Colombo. A cross-sectional entomological survey was conducted from April to June 2013 in 1469 premises located in a subdistrict of the City of Colombo. Types of breeding sites and, where found, their infestation with larvae or pupae were recorded. Furthermore, a questionnaire was administered to the occupants of these premises to record current practices of dengue vector control. The surveyed premises consisted of 1341 residential premises and 110 non-residential premises (11 schools, 99 work or public sites), 5 open lands, and 13 non-specified. In these 1469 premises, 15447 potential breeding sites suitable to host larvae of pupae were found; of these sites18.0% contained water. Among the 2775 potential breeding sites that contained water, 452 (16.3%) were positive for larvae and/or pupae. Schools were associated with the proportionally highest number of breeding sites; 85 out of 133 (63.9%) breeding sites were positive for larvae and/or pupae in schools compared with 338 out of 2288 (14.8%) in residential premises. The odds ratio (OR) for schools and work or public sites for being infested with larvae and/or pupae was 2.77 (95% CI 1.58, 4.86), when compared to residential premises. Occupants of 80.8% of the residential premises, 54.5% of the schools and 67.7% of the work or public sites reported using preventive measures. The main prevention practices were coverage of containers and elimination of mosquito breeding places. Occupants of residential premises were much more likely to practice preventive measures than were those of non-residential premises (OR 2.23; 1.49, 3.36). Schools and working sites were associated with the highest numbers of breeding sites and

  17. Dengue Virus Genome Uncoating Requires Ubiquitination.

    PubMed

    Byk, Laura A; Iglesias, Néstor G; De Maio, Federico A; Gebhard, Leopoldo G; Rossi, Mario; Gamarnik, Andrea V

    2016-06-28

    The process of genome release or uncoating after viral entry is one of the least-studied steps in the flavivirus life cycle. Flaviviruses are mainly arthropod-borne viruses, including emerging and reemerging pathogens such as dengue, Zika, and West Nile viruses. Currently, dengue virus is one of the most significant human viral pathogens transmitted by mosquitoes and is responsible for about 390 million infections every year around the world. Here, we examined for the first time molecular aspects of dengue virus genome uncoating. We followed the fate of the capsid protein and RNA genome early during infection and found that capsid is degraded after viral internalization by the host ubiquitin-proteasome system. However, proteasome activity and capsid degradation were not necessary to free the genome for initial viral translation. Unexpectedly, genome uncoating was blocked by inhibiting ubiquitination. Using different assays to bypass entry and evaluate the first rounds of viral translation, a narrow window of time during infection that requires ubiquitination but not proteasome activity was identified. In this regard, ubiquitin E1-activating enzyme inhibition was sufficient to stabilize the incoming viral genome in the cytoplasm of infected cells, causing its retention in either endosomes or nucleocapsids. Our data support a model in which dengue virus genome uncoating requires a nondegradative ubiquitination step, providing new insights into this crucial but understudied viral process. Dengue is the most significant arthropod-borne viral infection in humans. Although the number of cases increases every year, there are no approved therapeutics available for the treatment of dengue infection, and many basic aspects of the viral biology remain elusive. After entry, the viral membrane must fuse with the endosomal membrane to deliver the viral genome into the cytoplasm for translation and replication. A great deal of information has been obtained in the last decade

  18. Clinically Profiling Pediatric Patients with Dengue

    PubMed Central

    Pothapregada, Sriram; Kamalakannan, Banupriya; Thulasingham, Mahalaskhmy; Sampath, Srinivasan

    2016-01-01

    Objective: To study the clinical profile and outcome of dengue fever in children at a tertiary care hospital in Puducherry. Materials and Methods: All children (0-12 years of age) diagnosed and confirmed as dengue fever from August 2012 to January 2015 were reviewed retrospectively from hospital case records as per the revised World Health Organization guidelines for dengue fever. The diagnosis was confirmed by NS1 antigen-based ELISA test or dengue serology for IgM and IgG antibodies, and the data were analyzed using SPSS 16.0 statistical software. After collecting the data, all the variables were summarized by descriptive statistics. Results: Among the 261 confirmed cases of dengue fever non-severe and severe dengue infection was seen in 60.9% and 39.1%, respectively. The mean age (standard deviation) of the presentation was 6.9 + 3.3 years and male: female ratio was 1.2:1. The most common clinical manifestations were fever (94.6%), conjunctival congestion (89.6%), myalgia (81.9%), coryza (79.7%), headache (75.1%), palmar erythema (62.8%), and retro-orbital pain (51.3%). The common early warning signs at the time of admission were persistent vomiting (75.1%), liver enlargement (59.8%), cold and clammy extremities (45.2%), pain abdomen (31.0%), hypotension (29.5%), restlessness (26.4%), giddiness (23.0%), bleeding (19.9%), and oliguria (18.4%). The common manifestation of severe dengue infection was shock (39.1%), bleeding (19.9%), and multi-organ dysfunction (2.3%). The most common complications were liver dysfunction, acute respiratory distress syndrome, encephalopathy, pleural effusion, ascites, myocarditis, myositis, acute kidney injury, and disseminated intravascular coagulopathy. Platelet count did not always correlate well with the severity of bleeding. There were six deaths (2.3%) and out of them four presented with impaired consciousness (66.6%). The common causes for poor outcome were multiorgan failure, encephalopathy, and fluid refractory shock

  19. Climatic factors influencing dengue cases in Dhaka city: A model for dengue prediction

    PubMed Central

    Karim, Md. Nazmul; Munshi, Saif Ullah; Anwar, Nazneen; Alam, Md. Shah

    2012-01-01

    Background & objectives: Transmission of dengue virus depends on the presence of Aedes mosquito. Mosquito generation and development is known to be influenced by the climate. This study was carried out to examine whether the climatic factors data can be used to predict yearly dengue cases of Dhaka city, Bangladesh. Methods: Monthly reported dengue cases and climate data for the years 2000–2008 were obtained from the Directorate General of Health Services (DGHS) and Meteorological Department of Dhaka, Bangladesh, respectively. Data for the period 2000 to 2007 were used for development of a model through multiple linear regressions. Retrospective validation of the model was done with 2001, 2003, 2005 and 2008 data. Log transformation of the dependent variable was done to normalize data for linear regression. Average monthly humidity, rainfall, minimum and maximum temperature were used as independent variables and number of dengue cases reported monthly was used as dependent variable. Accuracy of the model for predicting outbreak was assessed through receiver operative characteristics (ROC) curve. Results: Climatic factors, i.e. rainfall, maximum temperature and relative humidity were significantly correlated with monthly reported dengue cases. The model incorporating climatic data of two-lag month explained 61 per cent of variation in number of reported dengue cases and this model was found to predict dengue outbreak (≥ 200 cases) with considerable accuracy [area under ROC curve = 0.89, 95%CI = (0.89-0.98)]. Interpretation & conclusions: Our results showed that the climate had a major effect on the occurrence of dengue infection in Dhaka city. Though the prediction model had some limitations in predicting the monthly number of dengue cases, it could forecast possible outbreak two months in advance with considerable accuracy. PMID:22885261

  20. Dengue vaccine: local decisions, global consequences.

    PubMed

    López-Gatell, Hugo; Alpuche-Aranda, Celia M; Santos-Preciado, José I; Hernández-Ávila, Mauricio

    2016-11-01

    As new vaccines against diseases that are prevalent in low- and middle-income countries gradually become available, national health authorities are presented with new regulatory and policy challenges. The use of CYD-TDV - a chimeric tetravalent, live-attenuated dengue vaccine - was recently approved in five countries. Although promising for public health, this vaccine has only partial and heterogeneous efficacy and may have substantial adverse effects. In trials, children who were aged 2-5 years when first given CYD-TDV were seven times more likely to be hospitalized for dengue, in the third year post-vaccination, than their counterparts in the control group. As it has not been clarified whether this adverse effect is only a function of age or is determined by dengue serostatus, doubts have been cast over the long-term safety of this vaccine in seronegative individuals of any age. Any deployment of the vaccine, which should be very cautious and only considered after a rigorous evaluation of the vaccine's risk-benefit ratio in explicit national and subnational scenarios, needs to be followed by a long-term assessment of the vaccine's effects. Furthermore, any implementation of dengue vaccines must not weaken the political and financial support of preventive measures that can simultaneously limit the impacts of dengue and several other mosquito-borne pathogens.

  1. Homotypic Dengue Virus Reinfections in Nicaraguan Children

    PubMed Central

    Waggoner, Jesse J.; Balmaseda, Angel; Gresh, Lionel; Sahoo, Malaya K.; Montoya, Magelda; Wang, Chunling; Abeynayake, Janaki; Kuan, Guillermina; Pinsky, Benjamin A.; Harris, Eva

    2016-01-01

    Background. Infection with any of the 4 related dengue virus serotypes (DENV-1–4) is thought to result in lifelong immunity to homotypic reinfection (ie, reinfection with the same serotype). Methods. Archived serum samples collected as part of an ongoing pediatric dengue cohort study in Nicaragua were tested for DENV by real-time reverse transcription polymerase chain reaction. Samples were collected from 2892 children who presented with an acute febrile illness clinically attributed to a non-DENV cause (hereafter, “C cases”). Test results were added to a database of previously identified symptomatic dengue cases in the cohort to identify repeat infections. Results. Four patients with homotypic DENV reinfections were identified and confirmed among 29 repeat DENV infections (13.8%) with serotype confirmation. Homotypic reinfections with DENV-1, DENV-2, and DENV-3 occurred 325–621 days after the initial infection. Each patient experienced 1 symptomatic dengue case and 1 DENV-positive C case, and 2 patients presented with symptomatic dengue during their second infection. These DENV-positive C cases did not elicit long-lived humoral immune responses, despite viremia levels of up to 6.44 log10 copies per mL of serum. Conclusions. We describe the first set of virologically confirmed homotypic DENV reinfections. Such cases challenge the current understanding of DENV immunity and have important implications for modeling DENV transmission. PMID:26984144

  2. Validation of dengue infection severity score

    PubMed Central

    Pongpan, Surangrat; Patumanond, Jayanton; Wisitwong, Apichart; Tawichasri, Chamaiporn; Namwongprom, Sirianong

    2014-01-01

    Objective To validate a simple scoring system to classify dengue viral infection severity to patients in different settings. Methods The developed scoring system derived from 777 patients from three tertiary-care hospitals was applied to 400 patients in the validation data obtained from another three tertiary-care hospitals. Percentage of correct classification, underestimation, and overestimation was compared. The score discriminative performance in the two datasets was compared by analysis of areas under the receiver operating characteristic curves. Results Patients in the validation data were different from those in the development data in some aspects. In the validation data, classifying patients into three severity levels (dengue fever, dengue hemorrhagic fever, and dengue shock syndrome) yielded 50.8% correct prediction (versus 60.7% in the development data), with clinically acceptable underestimation (18.6% versus 25.7%) and overestimation (30.8% versus 13.5%). Despite the difference in predictive performances between the validation and the development data, the overall prediction of the scoring system is considered high. Conclusion The developed severity score may be applied to classify patients with dengue viral infection into three severity levels with clinically acceptable under- or overestimation. Its impact when used in routine clinical practice should be a topic for further study. PMID:24623999

  3. Dengue vaccine: local decisions, global consequences

    PubMed Central

    López-Gatell, Hugo; Alpuche-Aranda, Celia M; Santos-Preciado, José I

    2016-01-01

    Abstract As new vaccines against diseases that are prevalent in low- and middle-income countries gradually become available, national health authorities are presented with new regulatory and policy challenges. The use of CYD-TDV – a chimeric tetravalent, live-attenuated dengue vaccine – was recently approved in five countries. Although promising for public health, this vaccine has only partial and heterogeneous efficacy and may have substantial adverse effects. In trials, children who were aged 2–5 years when first given CYD-TDV were seven times more likely to be hospitalized for dengue, in the third year post-vaccination, than their counterparts in the control group. As it has not been clarified whether this adverse effect is only a function of age or is determined by dengue serostatus, doubts have been cast over the long-term safety of this vaccine in seronegative individuals of any age. Any deployment of the vaccine, which should be very cautious and only considered after a rigorous evaluation of the vaccine’s risk–benefit ratio in explicit national and subnational scenarios, needs to be followed by a long-term assessment of the vaccine’s effects. Furthermore, any implementation of dengue vaccines must not weaken the political and financial support of preventive measures that can simultaneously limit the impacts of dengue and several other mosquito-borne pathogens. PMID:27821888

  4. [Clinical and epidemiological characteristic of dengue].

    PubMed

    Murillo-Llanes, Joel; Soto-Valenzuela, Humberto; Flores-Flores, Paula; Peraza-Garay, Felipe

    2007-01-01

    To describe the clinical and epidemiological characteristics of dengue fever (DF) and dengue hemorrhagic fever (DHF). A cross-sectional study was conducted in the Hospital General de Culiacan Dr. Bernardo J. Gastélum and the Hospital General de Zona 28 of IMSS from September to November 2003, with patients having dengue diagnosis, which was classified according to the WHO criteria. The statistical program Stata v6 was used for the analysis. 231 dengue cases (DF: 90.48 %; DHF 9.52 %) were included. Average age was 34.5 +/- 15 years. 61.7% of DF cases were women, while 77.3% of DHF cases were men. DHF cases went to the hospital in 4.7 +/- 2 days, while DF cases went in 3.4 +/- 2.2 days (p = 0.004). DHF cases had more often headache, retroocular pain, arthralgias, diarrhea and vomiting (p < 0.05). DF cases showed hemorrhagic manifestations (24.8%); plasma leakage (6.7%) and thrombocytopenia (34.4%); petequiae, gingival bleeding and epistaxis were associated to thrombocytopenia below 39 000/mm(3) (p < 0.05); neutropenia, prolonged partial thromboplastin time elevated transaminases were observed more often in DHF cases (p <0.05). the main variables associated with DHF were: male gender, fever, vomiting and gingival bleeding but not previous history of dengue; the major hemoconcentration, the major severity of thrombocytopenia.

  5. Dengue Vectors and their Spatial Distribution

    PubMed Central

    Higa, Yukiko

    2011-01-01

    The distribution of dengue vectors, Ae. aegypti and Ae. albopictus, is affected by climatic factors. In addition, since their life cycles are well adapted to the human environment, environmental changes resulting from human activity such as urbanization exert a great impact on vector distribution. The different responses of Ae. aegypti and Ae albopictus to various environments result in a difference in spatial distribution along north-south and urban-rural gradients, and between the indoors and outdoors. In the north-south gradient, climate associated with survival is an important factor in spatial distribution. In the urban-rural gradient, different distribution reflects a difference in adult niches and is modified by geographic and human factors. The direct response of the two species to the environment around houses is related to different spatial distribution indoors and outdoors. Dengue viruses circulate mainly between human and vector mosquitoes, and the vector presence is a limiting factor of transmission. Therefore, spatial distribution of dengue vectors is a significant concern in the epidemiology of the disease. Current technologies such as GIS, satellite imagery and statistical models allow researchers to predict the spatial distribution of vectors in the changing environment. Although it is difficult to confirm the actual effect of environmental and climate changes on vector abundance and vector-borne diseases, environmental changes caused by humans and human behavioral changes due to climate change can be expected to exert an impact on dengue vectors. Longitudinal monitoring of dengue vectors and viruses is therefore necessary. PMID:22500133

  6. Spatial and Temporal Patterns of Dengue Transmission along a Red Sea Coastline: A Longitudinal Entomological and Serological Survey in Port Sudan City

    PubMed Central

    Seidahmed, Osama M. E.; Hassan, Safa A.; Soghaier, Mohamed A.; Siam, Hanna A. M.; Ahmed, Fayez T. A.; Elkarsany, Mubarak M.; Sulaiman, Suad M.

    2012-01-01

    Background Dengue is an emerging health problem in several coastlines along the Red Sea. The objective of the present work is to elucidate spatial and temporal patterns of dengue transmission in Port Sudan. Methods/Findings A longitudinal study with three cross-sectional surveys was carried out in upper, middle and lower class neighborhoods, from November 2008 to October 2009. Monthly, entomological surveys were followed by serological surveys in dengue vector-positive houses. Meteorological records were obtained from two weather stations in the city during the same time. Overall, 2825 houses were inspected. Aedes aegypti represented 65% (35,714/54,944) and 68% (2526/3715) of the collected larvae and pupae, respectively. Out of 4640 drinking water containers, 2297 were positive for Ae. aegypti. Clay-pots “Zeirr” followed by plastic barrels were key productive containers for pupae of dengue vector, 63% (n = 3959) and 26% (n = 1651), respectively. A total of 791 blood samples were tested using PanBio Capture/Indirect IgM ELISA. Overall, the sero-prevalence rate of dengue ranged between 3%–8% (41/791), compared to an incidence of 29–40 new cases per 10,000 (193/54886) in the same examined population. Lower and middle class neighborhoods had higher entomological indices compared with upper class ones (p<0.001). Although, dengue incidence rate was significantly lower in the middle and lower class neighborhoods (F = 73.97, d.f. = 2, p<0.001), no difference in IgM prevalence was shown. The city is subject to two transmission peaks in the winter (i.e. November–January), and summer (i.e. June–August). The serological peaks of dengue are preceded by entomological peaks that occur before the onset of winter (November) and summer (March) respectively. Conclusion Dengue incidence is heterogeneously distributed across the neighborhoods of Port Sudan and exhibits a bi-cyclic intra-annual pattern. Hence, it should be feasible to carry out timely vector

  7. Spatial and temporal patterns of dengue transmission along a Red Sea coastline: a longitudinal entomological and serological survey in Port Sudan city.

    PubMed

    Seidahmed, Osama M E; Hassan, Safa A; Soghaier, Mohamed A; Siam, Hanna A M; Ahmed, Fayez T A; Elkarsany, Mubarak M; Sulaiman, Suad M

    2012-01-01

    Dengue is an emerging health problem in several coastlines along the Red Sea. The objective of the present work is to elucidate spatial and temporal patterns of dengue transmission in Port Sudan. A longitudinal study with three cross-sectional surveys was carried out in upper, middle and lower class neighborhoods, from November 2008 to October 2009. Monthly, entomological surveys were followed by serological surveys in dengue vector-positive houses. Meteorological records were obtained from two weather stations in the city during the same time. Overall, 2825 houses were inspected. Aedes aegypti represented 65% (35,714/54,944) and 68% (2526/3715) of the collected larvae and pupae, respectively. Out of 4640 drinking water containers, 2297 were positive for Ae. aegypti. Clay-pots "Zeirr" followed by plastic barrels were key productive containers for pupae of dengue vector, 63% (n = 3959) and 26% (n = 1651), respectively. A total of 791 blood samples were tested using PanBio Capture/Indirect IgM ELISA. Overall, the sero-prevalence rate of dengue ranged between 3%-8% (41/791), compared to an incidence of 29-40 new cases per 10,000 (193/54886) in the same examined population. Lower and middle class neighborhoods had higher entomological indices compared with upper class ones (p<0.001). Although, dengue incidence rate was significantly lower in the middle and lower class neighborhoods (F = 73.97, d.f. = 2, p<0.001), no difference in IgM prevalence was shown. The city is subject to two transmission peaks in the winter (i.e. November-January), and summer (i.e. June-August). The serological peaks of dengue are preceded by entomological peaks that occur before the onset of winter (November) and summer (March) respectively. Dengue incidence is heterogeneously distributed across the neighborhoods of Port Sudan and exhibits a bi-cyclic intra-annual pattern. Hence, it should be feasible to carry out timely vector control measures to prevent or reduce dengue transmission.

  8. Gravitraps for management of dengue clusters in Singapore.

    PubMed

    Lee, Caleb; Vythilingam, Indra; Chong, Chee-Seng; Abdul Razak, Muhammad Aliff; Tan, Cheong-Huat; Liew, Christina; Pok, Kwoon-Yong; Ng, Lee-Ching

    2013-05-01

    Although Singapore has an intensive dengue control program, dengue remains endemic with regular outbreaks. We report development and use of a novel adult oviposition trap, the Gravitrap, in managing dengue cluster areas. The Gravitrap is a simple, hay infusion-filled cylindrical trap with a sticky inner surface to serve as an oviposition site for gravid female Aedes mosquitoes. Wire gauze fitted above the water level minimizes the risk of it being an unwanted breeding habitat. The Gravitrap was deployed in 11 dengue cluster areas throughout Singapore. Aedes aegypti was the predominant mosquito caught in the trap and some (5.73%) were found to be positive for dengue virus.

  9. Current Status of Dengue Therapeutics Research and Development

    PubMed Central

    Ooi, Eng Eong; Vasudevan, Subhash G.

    2017-01-01

    Abstract Dengue is a significant global health problem. Even though a vaccine against dengue is now available, which is a notable achievement, its long-term protective efficacy against each of the 4 dengue virus serotypes remains to be definitively determined. Consequently, drugs directed at the viral targets or critical host mechanisms that can be used safely as prophylaxis or treatment to effectively ameliorate disease or reduce disease severity and fatalities are still needed to reduce the burden of dengue. This review will provide a brief account of the status of therapeutics research and development for dengue. PMID:28403438

  10. Dengue Fever with rectus sheath hematoma: a case report.

    PubMed

    Sharma, Anurag; Bhatia, Sonia; Singh, Rajendra Pratap; Malik, Gaurav

    2014-04-01

    Dengue fever, also known as breakbone fever, is an infectious tropical disease caused by the Dengue virus. It is associated with a number of complications, which are well documented. However, Dengue fever associated with rectus sheath hematoma (RSH) is a very rare complication. Only one case report has been published prior supporting the association of Dengue fever with RSH. We report a case of Dengue fever who presented with RSH and was successfully treated conservatively. RSH is also an uncommon cause of acute abdominal pain. It is accumulation of blood in the sheath of the rectus abdominis, secondary to rupture of an epigastric vessel or muscle tear.

  11. Severe thrombotic events associated with dengue fever, Brazil.

    PubMed

    da Costa, Paulo Sérgio Gonçalves; Ribeiro, Geyza Machado; Junior, Cleber Soares; da Costa Campos, Lenilton

    2012-10-01

    Dengue fever has been a major problem in hospital settings in Brazil for the past 15 years. The main concern has been the severe forms, i.e., dengue hemorrhagic fever and dengue shock syndrome. Hemorrhagic events of different degrees have also been a major concern. We report five cases of large vein thrombotic events associated with the acute phase of dengue fever, including a previously non-reported case of mesenteric vein thrombosis. Complications such as these could have been overlooked in the diagnosis of dengue fever, given that the major concern is the hemorrhagic event.

  12. Understanding the relative importance of global dengue risk factors.

    PubMed

    Lowe, Rachel

    2015-10-01

    Dengue is a mosquito-transmitted viral infection of major international public health concern. Global environmental and socio-economic change has created ideal conditions for the global expansion of dengue transmission. Innovative modelling tools help in understanding the global determinants of dengue risk and the relative impact of environmental and socio-economic factors on dengue transmission and spread. While climatic factors may act as a limiting factor on the global scale, other processes may play a dominant role at the local level. Understanding the spatial scales at which environmental and socio-economic factors dominate can help to target appropriate dengue control and prevention strategies.

  13. Current Status of Dengue Therapeutics Research and Development.

    PubMed

    Low, Jenny G H; Ooi, Eng Eong; Vasudevan, Subhash G

    2017-03-01

    Dengue is a significant global health problem. Even though a vaccine against dengue is now available, which is a notable achievement, its long-term protective efficacy against each of the 4 dengue virus serotypes remains to be definitively determined. Consequently, drugs directed at the viral targets or critical host mechanisms that can be used safely as prophylaxis or treatment to effectively ameliorate disease or reduce disease severity and fatalities are still needed to reduce the burden of dengue. This review will provide a brief account of the status of therapeutics research and development for dengue. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

  14. 75 FR 6211 - Prospective Grant of Exclusive License: Purified Inactivated Dengue Tetravalent Vaccine...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-08

    ... Viruses and Chimeric Dengue Viruses''-- European Patent Application Number 02739358.6, filed May 22, 2002... Deletion in the 3'-UTR of Dengue Types 1,2,3, and 4, or Antigenic Chimeric Dengue Viruses 1,2,3, and 4... which enhance the replication of dengue virus type 4 and an antigenic chimeric dengue virus type 2/4...

  15. 78 FR 43219 - Prospective Grant of Exclusive License: Live Attenuated Dengue Tetravalent Vaccine Containing a...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-19

    ... et al., ``Development of Mutations Useful for Attenuating Dengue Viruses and Chimeric Dengue Viruses... Antigenic Chimeric Dengue Viruses 1,2,3, And 4'', United States Patent Application Number 10/970,640 (now...., ``Mutations which enhance the replication of dengue virus type 4 and an antigenic chimeric dengue virus type...

  16. Dengue and Chikungunya Vector Control Pocket Guide

    DTIC Science & Technology

    2014-05-01

    mosquito eggs, larvae, or pupae . Examples of such items are tarps, discarded bottles, flower pot saucers, and rain gauges. In areas where there...containers both inside and outside o f homes. Surveillance of larvae and pupae can be done by visually inspecting containers for immature mosquitoes and...sample bags or another type of storage container can be used if larvae or pupae are being returned to the laboratory. Navy

  17. Safety Testing of Dengue-1 and Dengue-3 Seeds for Human Challenges, Unattenuated.

    DTIC Science & Technology

    1987-10-26

    Maryland 21701-5012 ELEMENT NO. NO. 3M1- NO0. CESSION NO. 11. TITLE (Inciude Security Clanafication) 627A 127A80I C E 09 (U) Safety Testing of Dengue -1...and Dengue -3 Seeds for Human Challenges, Unattenuated 12. PERSONAL AUrWOR(S) Potash, Loui.s 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT...of necessary and identify by block number) FIELD GROUP SUB-GROUP 06 13 ngue-M- Dengue -3; Hepatitis A; Viral seeds; Vaccine no;’-- 03 I 19. ABSTRACI’ 4

  18. Best Practices in Dengue Surveillance: A Report from the Asia-Pacific and Americas Dengue Prevention Boards

    PubMed Central

    Beatty, Mark E.; Stone, Amy; Fitzsimons, David W.; Hanna, Jeffrey N.; Lam, Sai Kit; Vong, Sirenda; Guzman, Maria G.; Mendez-Galvan, Jorge F.; Halstead, Scott B.; Letson, G. William; Kuritsky, Joel; Mahoney, Richard; Margolis, Harold S.

    2010-01-01

    Background Dengue fever is a virus infection that is spread by the Aedes aegypti mosquito and can cause severe disease especially in children. Dengue fever is a major problem in tropical and sub-tropical regions of the world. Methodology/Principal Findings We invited dengue experts from around the world to attend meetings to discuss dengue surveillance. We reviewed literature, heard detailed reports on surveillance programs, and shared expert opinions. Results Presentations by 22 countries were heard during the 2.5 day meetings. We describe the best methods of surveillance in general, the stakeholders in dengue surveillance, and the steps from mosquito bite to reporting of a dengue case to explore how best to carry out dengue surveillance. We also provide details and a comparison of the dengue surveillance programs by the presenting countries. Conclusions/Significance The experts provided recommendations for achieving the best possible data from dengue surveillance accepting the realities of the real world (e.g., limited funding and staff). Their recommendations included: (1) Every dengue endemic country should make reporting of dengue cases to the government mandatory; (2) electronic reporting systems should be developed and used; (3) at minimum dengue surveillance data should include incidence, hospitalization rates, deaths by age group; (4) additional studies should be completed to check the sensitivity of the system; (5) laboratories should share expertise and data; (6) tests that identify dengue virus should be used in patients with fever for four days or less and antibody tests should be used after day 4 to diagnose dengue; and (7) early detection and prediction of dengue outbreaks should be goals for national surveillance systems. PMID:21103381

  19. [Evaluation of an educational module on dengue and Aedes aegypti for schoolchildren in Honduras].

    PubMed

    Avila Montes, Gustavo Adolfo; Martínez, Mercedes; Sherman, Catalina; Fernández Cerna, Eduardo

    2004-08-01

    To evaluate the effectiveness of a special course on environmental health and dengue, given to primary school students and intended to promote behavioral changes in the mothers of those students that would lead to the safe handling of water, adequate disposal of trash, and control of household breeding sites of Aedes aegypti, the mosquito vector for dengue. In the period from April to November 2002 a community field trial was carried out that included four public schools in the city of Comayaguela, Honduras. Two of the schools formed the intervention group, and the two others made up the comparison or control group. The data collection activities before and after the intervention included knowledge tests for the schoolchildren and the teachers; surveys of the knowledge, attitudes, and practices of the students' mothers; entomological surveys (systematic checking in order to find water containers, to search for mosquito larvae) in the homes of the schoolchildren; in-depth interviews with the students' mothers; observation in the classrooms; and postintervention focus group with the teachers. During the intervention period the largest epidemic of classical dengue ever in the history of Tegucigalpa, the capital of Honduras, occurred. That event prompted the Secretariat of Health to undertake large-scale control activities. In the two intervention schools there was a significant increase in the students' knowledge of the following three variables: dengue caused by a virus, life cycle of the vector, and reduction of breeding sites, which is the most effective measure for controlling the vector (P < 0.0001 for all those increases in knowledge). There were also significant increases in the knowledge of the same variables among the teachers in the intervention schools: dengue caused by a virus (P = 0.03), life cycle of the vector (P = 0.01), and reduction of breeding sites (P = 0.004). Reducing the number of breeding sites as being the best measure for controlling Aedes

  20. Reduction in dengue cases observed during mass control of Aedes (Stegomyia) in street catch basins in an endemic urban area in Colombia

    PubMed Central

    Ocampo, Clara B.; Mina, Neila Julieth; Carabalí, Mabel; Alexander, Neal; Osorio, Lyda

    2015-01-01

    Dengue incidence continues to increase globally and, in the absence of an efficacious vaccine, prevention strategies are limited to vector control. It has been suggested that targeting the most productive breeding sites instead of all water-holding containers could be a cost-effective vector control strategy. We sought to identify and continuously control the most productive Aedes (Stegomyia) breeding site in an endemic urban area in Colombia and followed the subsequent incidence of dengue. In the urban area of Guadalajara de Buga, southwestern Colombia, potential breeding sites inside and outside houses were first characterized, and local personnel trained to assess their productivity based on the pupae/person index. Simultaneously, training and monitoring were implemented to improve the dengue case surveillance system. Entomological data and insecticide resistance studies were used to define the targeted intervention. Then, a quasi-experimental design was used to assess the efficacy of the intervention in terms of the positivity index of the targeted and non- targeted breeding sites, and the impact on dengue cases. Street catch basins (storm drains) were the potential breeding site most frequently found containing Aedes immature stages in the baseline (58.3% of 108). Due to the high resistance to temephos (0% mortality after 24 h), the intervention consisted of monthly application of pyriproxyfen in all the street catch basins (n = 4800). A significant decrease in catch basins positivity for Aedes larvae was observed after each monthly treatment (p < 0.001). Over the intervention period, a reduction in the dengue incidence in Buga was observed (rate ratio 0.19, 95% CI 0.12–0.30, p < 0.0001) after adjusting for autocorrelation and controlling with a neighboring town, Palmira, This study highlights the importance of street catch basins as Aedes breeding sites and suggests that their targeted control could help to decrease dengue transmission in such areas. PMID

  1. Reduction in dengue cases observed during mass control of Aedes (Stegomyia) in street catch basins in an endemic urban area in Colombia.

    PubMed

    Ocampo, Clara B; Mina, Neila Julieth; Carabalí, Mabel; Alexander, Neal; Osorio, Lyda

    2014-04-01

    Dengue incidence continues to increase globally and, in the absence of an efficacious vaccine, prevention strategies are limited to vector control. It has been suggested that targeting the most productive breeding sites instead of all water-holding containers could be a cost-effective vector control strategy. We sought to identify and continuously control the most productive Aedes (Stegomyia) breeding site in an endemic urban area in Colombia and followed the subsequent incidence of dengue. In the urban area of Guadalajara de Buga, southwestern Colombia, potential breeding sites inside and outside houses were first characterized, and local personnel trained to assess their productivity based on the pupae/person index. Simultaneously, training and monitoring were implemented to improve the dengue case surveillance system. Entomological data and insecticide resistance studies were used to define the targeted intervention. Then, a quasi-experimental design was used to assess the efficacy of the intervention in terms of the positivity index of the targeted and non- targeted breeding sites, and the impact on dengue cases. Street catch basins (storm drains) were the potential breeding site most frequently found containing Aedes immature stages in the baseline (58.3% of 108). Due to the high resistance to temephos (0% mortality after 24h), the intervention consisted of monthly application of pyriproxyfen in all the street catch basins (n=4800). A significant decrease in catch basins positivity for Aedes larvae was observed after each monthly treatment (p<0.001). Over the intervention period, a reduction in the dengue incidence in Buga was observed (rate ratio 0.19, 95% CI 0.12-0.30, p<0.0001) after adjusting for autocorrelation and controlling with a neighboring town, Palmira, This study highlights the importance of street catch basins as Aedes breeding sites and suggests that their targeted control could help to decrease dengue transmission in such areas.

  2. Green-synthesized silver nanoparticles as a novel control tool against dengue virus (DEN-2) and its primary vector Aedes aegypti.

    PubMed

    Sujitha, Vasu; Murugan, Kadarkarai; Paulpandi, Manickam; Panneerselvam, Chellasamy; Suresh, Udaiyan; Roni, Mathath; Nicoletti, Marcello; Higuchi, Akon; Madhiyazhagan, Pari; Subramaniam, Jayapal; Dinesh, Devakumar; Vadivalagan, Chithravel; Chandramohan, Balamurugan; Alarfaj, Abdullah A; Munusamy, Murugan A; Barnard, Donald R; Benelli, Giovanni

    2015-09-01

    Dengue is an arthropod-borne viral infection mainly vectored through the bite of Aedes mosquitoes. Recently, its transmission has strongly increased in urban and semi-urban areas of tropical and sub-tropical regions worldwide, becoming a major international public health concern. There is no specific treatment for dengue. Its prevention and control solely depends on effective vector control measures. In this study, we proposed the green-synthesis of silver nanoparticles (AgNP) as a novel and effective tool against the dengue serotype DEN-2 and its major vector Aedes aegypti. AgNP were synthesized using the Moringa oleifera seed extract as reducing and stabilizing agent. AgNP were characterized using a variety of biophysical methods including UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and sorted for size categories. AgNP showed in vitro antiviral activity against DEN-2 infecting vero cells. Viral titer was 7 log10 TCID50/ml in control (AgNP-free), while it dropped to 3.2 log10 TCID50/ml after a single treatment with 20 μl/ml of AgNP. After 6 h, DEN-2 yield was 5.8 log10 PFU/ml in the control, while it was 1.4 log10 PFU/ml post-treatment with AgNP (20 μl/ml). AgNP were highly effective against the dengue vector A. aegypti, with LC50 values ranging from 10.24 ppm (I instar larvae) to 21.17 ppm (pupae). Overall, this research highlighted the concrete potential of green-synthesized AgNP in the fight against dengue and its primary vector A. aegypti. Further research on structure-activity relationships of AgNP against other dengue serotypes is urgently required.

  3. The Association of Cytokines with Severe Dengue in Children

    PubMed Central

    Mangione, Julia N.A.; Huy, Nguyen Tien; Lan, Nguyen Thi Phuong; Mbanefo, Evaristus Chibunna; Ha, Tran Thi Ngoc; Bao, Lam Quoc; Nga, Cao Thi Phi; Tuong, Vo Van; Dat, Tran Van; Thuy, Tran Thi; Tuan, Ha Manh; Huong, Vu Thi Que; Hirayama, Kenji

    2014-01-01

    Background: Dengue virus infection is a major public health problem. A hypothesis put forward for severe dengue is the cytokine storm, a sudden increase in cytokines that induces vascular permeability. Previous studies and our recent meta-analysis showed that IL-6, IL-8, IFNγ, TNFα, VEGF-A and VCAM-1 are associated with dengue shock syndrome. Therefore, in this study we aim to validate the association of these cytokines with severe dengue. Methods & Findings: In a hospital based-case control study in Vietnam, children with dengue fever, other febrile illness and healthy controls were recruited. Dengue virus infection was confirmed by several diagnostic tests. Multiplex immunoassay using Luminex technology was used to measure cytokines simultaneously. A positive association with dengue shock syndrome was found for VCAM-1, whereas a negative association was found for IFNγ. Furthermore, multivariate logistic analysis also showed that VCAM-1 and IFNγ were independently correlated with dengue shock syndrome. Conclusion: IFNγ and VCAM-1 were associated with dengue shock syndrome, although their role in the severe dengue pathogenesis remains unclear. Additional studies are required to shed further light on the function of these cytokines in severe dengue. PMID:25589878

  4. Estimation of dengue infection for travelers in Thailand.

    PubMed

    Polwiang, Sittisede

    2016-01-01

    Dengue infection among travelers has become one of the most public health concerns in present days. The importation of dengue virus can initiate an outbreak in non-endemic regions. Thailand is one of the countries topping the list of highest dengue infections in travelers. This study estimates the risk of dengue infection among travelers during their visit in Thailand by using a mathematical model with seasonal variations. The risk of dengue infection in high dengue season is 2.50-4.07 times that on low dengue season depending on the locations. The average daily risk of dengue infections of Thailand per 100,000 travelers is 2.14 and 7.03 for low and high dengue season, respectively. The highest rate of infection is Rayong and the lowest rate is Sing Buri. Several popular tourist provinces are high dengue endemic areas. This study provides useful information on dengue infection among travelers. The main factors are the time of arrival in the year, the duration of stay of the travelers and the locations where the travelers spend most of their time. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Diagnosis of Dengue Infection Using Conventional and Biosensor Based Techniques.

    PubMed

    Parkash, Om; Shueb, Rafidah Hanim

    2015-10-19

    Dengue is an arthropod-borne viral disease caused by four antigenically different serotypes of dengue virus. This disease is considered as a major public health concern around the world. Currently, there is no licensed vaccine or antiviral drug available for the prevention and treatment of dengue disease. Moreover, clinical features of dengue are indistinguishable from other infectious diseases such as malaria, chikungunya, rickettsia and leptospira. Therefore, prompt and accurate laboratory diagnostic test is urgently required for disease confirmation and patient triage. The traditional diagnostic techniques for the dengue virus are viral detection in cell culture, serological testing, and RNA amplification using reverse transcriptase PCR. This paper discusses the conventional laboratory methods used for the diagnosis of dengue during the acute and convalescent phase and highlights the advantages and limitations of these routine laboratory tests. Subsequently, the biosensor based assays developed using various transducers for the detection of dengue are also reviewed.

  6. Dengue: the risk to developed and developing countries.

    PubMed Central

    Monath, T P

    1994-01-01

    Dengue viruses are members of the Flaviviridae, transmitted principally in a cycle involving humans and mosquito vectors. In the last 20 years the incidence of dengue fever epidemics has increased and hyperendemic transmission has been established over a geographically expanding area. A severe form, dengue hemorrhagic fever (DHF), is an immunopathologic disease occurring in persons who experience sequential dengue infections. The risk of sequential infections, and consequently the incidence of DHF, has risen dramatically, first in Asia and now in the Americas. At the root of the emergence of dengue as a major health problem are changes in human demography and behavior, leading to unchecked populations of and increased exposure to the principal domestic mosquito vector, Aedes aegypti. Virus-specified factors also influence the epidemiology of dengue. Speculations on future events in the epidemiology, evolution, and biological expression of dengue are presented. Images PMID:8146129

  7. Dengue vaccine: a valuable asset for the future.

    PubMed

    Jindal, Harashish; Bhatt, Bhumika; Malik, Jagbir Singh; S K, Shashikantha

    2014-01-01

    Dengue has emerged as one of the major global public health problems. The disease has broken out of its shell and has spread due to increased international travel and climatic changes. Globally, over 2.5 billion people accounting for >40% of the world's population are at risk from dengue. Since the 1940s, dengue vaccines have been under investigation. A live-attenuated tetravalent vaccine based on chimeric yellow fever-dengue virus (CYD-TDV) has progressed to phase III efficacy studies. Dengue vaccine has been found to be a cost-effective intervention to reduce morbidity and mortality. Current dengue vaccine candidates aim to protect against the 4 dengue serotypes, but the recent discovery of a fifth serotype could complicate vaccine development. In recent years, an urgent need has been felt for a vaccine to prevent the morbidity and mortality from this disease in a cost-effective way.

  8. Vaccines for the prevention of dengue: development update.

    PubMed

    Thomas, Stephen J; Endy, Timothy P

    2011-06-01

    The dengue viruses (DENV) are mosquito-borne flaviviruses which cause a spectrum of clinical disease known as "dengue," and have emerged and re-emerged as a significant global health problem. It is estimated more than 120 countries currently have endemic DENV transmission, 55% of the world's population is at risk of infection, and there are between 70-500 million infections of which 2.1 million are clinically severe resulting in 21,000 deaths annually. By all estimates the global dengue problem will continue to worsen due to the increasing mobility of the population, ecological changes, and the inability to effectively sustain vector control. There are no licensed antivirals or vaccines to treat or prevent dengue. The development and widespread use of a safe and efficacious dengue vaccine is required to significantly reduce the global dengue burden. In this review the authors discuss dengue vaccines currently in the pre-clinical and clinical development pipeline.

  9. Unusual Presentation of Dengue Fever-Cerebral Venous Thrombosis

    PubMed Central

    Vairamon, Pradhosh M; Gowtham, Thiruvengadam; Das, Ashok Kumar

    2015-01-01

    Dengue infection can present as febrile illness with thrombocytopenia, dengue shock syndrome and dengue haemorrhagic fever. Neurological manifestation of dengue infection is more predominant in endemic region. Here, we report a case with unusual neurological presentation of dengue infection. A 16-year-old boy presented with fever for two week duration, headache and double vision involving left eye for two days. He had multiple erythematous rashes all over the body on 3rd day and treated conservatively. On examination he had bilateral papilloedema, left eye restricted abduction. His investigation revealed thrombocytopenia and positive dengue serology. His MRI brain with venogram showed bilateral transverse sinus thrombosis. Hence he was diagnosed as cerebral venous thrombosis due to dehydration with underlying dengue infection. He was hydrated and managed conservatively. On 3rd day his double vision started improving. His repeat MR Venogram was done after two week duration, which revealed recanalisation of bilateral transverse sinus. PMID:26266153

  10. Diagnosis of Dengue Infection Using Conventional and Biosensor Based Techniques

    PubMed Central

    Parkash, Om; Hanim Shueb, Rafidah

    2015-01-01

    Dengue is an arthropod-borne viral disease caused by four antigenically different serotypes of dengue virus. This disease is considered as a major public health concern around the world. Currently, there is no licensed vaccine or antiviral drug available for the prevention and treatment of dengue disease. Moreover, clinical features of dengue are indistinguishable from other infectious diseases such as malaria, chikungunya, rickettsia and leptospira. Therefore, prompt and accurate laboratory diagnostic test is urgently required for disease confirmation and patient triage. The traditional diagnostic techniques for the dengue virus are viral detection in cell culture, serological testing, and RNA amplification using reverse transcriptase PCR. This paper discusses the conventional laboratory methods used for the diagnosis of dengue during the acute and convalescent phase and highlights the advantages and limitations of these routine laboratory tests. Subsequently, the biosensor based assays developed using various transducers for the detection of dengue are also reviewed. PMID:26492265

  11. Clinical and Oral Implications of Dengue Fever: A Review

    PubMed Central

    Roopashri, G; Vaishali, M R; David, Maria Priscilla; Baig, Muqeet; Navneetham, Anuradha; Venkataraghavan, Karthik

    2015-01-01

    Dengue is a viral infection with fatal potential complications. It is also called as break-bone fever. Worldwide dengue infection is the most common mosquito-borne viral disease. It is caused by vector Aedesa egypti and represents a major public health issue in more than 100 tropical countries. The word dengue is obtained from Swahili phrase Ka-dinga pepo meaning “cramplikeseizure.” Dengue viral infections are characterized by abrupt febrile illness, but can also lead to significant morbidity and mortality. Hence, it requires an early and correct diagnosis. Gingival bleeding is the most common oral manifestation of dengue infection. Although oral lesions are uncommon in dengue infections and if manifested, may be mistaken for bleeding disorders. This review emphasizes the significance of oral lesions as it may be the early indicators of dengue hemorrhagic fever. PMID:25859113

  12. The enzyme 3-hydroxykynurenine transaminase as potential target for 1,2,4-oxadiazoles with larvicide activity against the dengue vector Aedes aegypti.

    PubMed

    Oliveira, Vanessa S; Pimenteira, Cecília; da Silva-Alves, Diana C B; Leal, Laylla L L; Neves-Filho, Ricardo A W; Navarro, Daniela M A F; Santos, Geanne K N; Dutra, Kamilla A; dos Anjos, Janaína V; Soares, Thereza A

    2013-11-15

    The mosquito Aedes aegypti is the vector agent responsible for the transmission of yellow fever and dengue fever viruses to over 80 million people in tropical and subtropical regions of the world. Exhaustive efforts have lead to a vaccine candidate with only 30% effectiveness against the dengue virus and failure to protect patients against the serotype 2. Hence, vector control remains the most viable route to dengue fever control programs. We have synthesized a class of 1,2,4-oxadiazole derivatives whose most biologically active compounds exhibit potent activity against Aedes aegypti larvae (ca. of 15 ppm) and low toxicity in mammals. Exposure to these larvicides results in larvae pigmentation in a manner correlated with the LC50 measurements. Structural comparisons of the 1,2,4-oxadiazole nucleus against known inhibitors of insect enzymes allowed the identification of 3-hydroxykynurenine transaminase as a potential target for these synthetic larvicides. Molecular docking calculations indicate that 1,2,4-oxadiazole compounds can bind to 3-hydroxykynurenine transaminase with similar conformation and binding energies as its crystallographic inhibitor 4-(2-aminophenyl)-4-oxobutanoic acid.

  13. Larvicidal activity of the leaf extracts of Spondias mombin Linn. (Anacardiaceae) from various solvents against malarial, dengue and filarial vector mosquitoes (Diptera: Culicidae).

    PubMed

    Eze, Elijah Ajaegbu; Danga, Simon Pierre Yinyang; Okoye, Festus Basden Chiedu

    2014-12-01

    Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus are vector mosquitoes of dengue, malaria, and filariasis, respectively. Since no vaccine is available to treat these diseases, the control of the main mosquito vectors is essential. As conventional insecticides have limited success, plants may be alternative larvicidal agents, since they contain a rich source of bioactive chemicals. The aim of this study was to evaluate the larvicidal activity of methanol crude extract, hexane, dichloromethane, acetone, ethyl acetate and methanol fractions of Spondias mombin leaf against IV instar larvae of dengue, malaria, and lymphatic filariasis vector mosquitoes. A total of 25, IV instar larvae of each target mosquito species were exposed to various concentrations (125-1000 ppm) and were assayed in the laboratory by using the protocol of WHO 2005; the LC50 values were determined by Probit analysis. Hexane, dichloromethane and acetone fractions were the most effective against Ae. aegypti with LC50 values of 22.54, 42.13, 45.18 ppm, respectively. Hexane fraction registered the highest activity with LC50 of 92.20 ppm against An. gambiae. It was still hexane fraction that showed better toxicity with LC50 of 326.53 ppm against Cx. quinquefasciatus. The Spondias mombin leaf extracts proved to be a strong candidate for a natural, safe and stable mosquito larvicide to be used in population control of Ae. aegypti, An. gambiae and Cx. quinquefasciatus and so may replace the conventional Diclorvos to control malaria, dengue and filariasis in Nigeria.

  14. A Video-Tracking Analysis-Based Behavioral Assay for Larvae of Anopheles pseudopunctipennis and Aedes aegypti (Diptera: Culicidae).

    PubMed

    Gonzalez, Paula V; Alvarez Costa, Agustín; Masuh, Héctor M

    2017-05-01

    Aedes aegypti (L.) is the primary vector of dengue, yellow fever, Zika, and chikungunya viruses, whereas Anopheles pseudopunctipennis (Theobald) is the principal vector for malaria in Latin America. The larval stage of these mosquitoes occurs in very different development habitats, and the study of their respective behaviors could give us valuable information to improve larval control. The aim of this study was to set up a bioassay to study basic larval behaviors using a video-tracking software. Larvae of An. pseudopunctipennis came from two localities in Salta Province, Argentina, while Ae. aegypti larvae were of the Rockefeller laboratory strain. Behaviors of individual fourth-instar larvae were documented in an experimental petri dish arena using EthoVision XT10.1 video-tracking software. The overall level of movement of larval An. pseudopunctipennis was lower than that for Ae. aegypti, and, while moving, larval An. pseudopunctipennis spent significantly more time swimming near the wall of the arena (thigmotaxis). This is the first study that analyzes the behavior of An. pseudopunctipennis larvae. The experimental system described here may be useful for future studies on the effect of physiological, toxicological, and chemosensory stimuli on larval behaviors. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. [A possible fifth dengue virus serotype].

    PubMed

    da Silva Voorham, Júlia M

    2014-01-01

    Sylvatic dengue viruses are both evolutionarily and ecologically distinguishable from the human dengue virus (DENV). Sporadic episodes of sylvatic human infections in West Africa and Southeast Asia suggest that sylvatic DENV regularly come into contact with human beings. Following a study on the sylvatic transmission cycle in Malaysia in 2007, researchers announced that a new DENV serotype, DENV-5, had been discovered. Scientists are still sceptical about these new findings, and indicate that more data is necessary to determine whether this 'new' virus really is a different serotype or whether it is a variant of one of the four DENV serotypes already known. The good news is that this new variant has not yet established itself in the human transmission cycle. However, if it really is a new serotype this will have implications for the long-term control of dengue using vaccines currently under development.

  16. Impediments of reporting dengue cases in India.

    PubMed

    Das, Sushmita; Sarfraz, Asim; Jaiswal, Nitesh; Das, Pradeep

    2017-03-02

    Dengue has emerged as one of the most important mosquito-borne, fatal flaviviral disease, apparently expanding as a global health problem. An estimated 3.6 billion people are at risk for dengue, with 50 million infections per year occurring across 100 countries globally. The annual number of dengue fever cases in India is many times higher than it is officially reported. This under reporting would play a major role in the government's decision-making. Underestimating of the disease in India encumbers its people from taking preventive measures, discourages efforts to ensnare the sources of the disease and deliberates efforts for vaccine research. In this article, we highlight the probable impediments of under reporting leading to its impact on national and global public health and also offer key remedies to effectively address the issues across the clinics to the community level.

  17. Dengue Virus Evolution and Virulence Models

    PubMed Central

    Rico-Hesse, Rebeca

    2008-01-01

    Dengue virus transmission has increased dramatically in the past 2 decades, making this virus one of the most important mosquito-borne human pathogens. The emergence of dengue hemorrhagic fever in most tropical countries has made its control a public health priority, but no vaccines or treatments exist. Little is understood about dengue virus pathogenesis, because no other animals develop symptoms of disease, and research, therefore, has been limited to studies involving patients. Although epidemiologic and evolutionary studies have pointed to host and viral factors in determining disease outcome, only recently developed models could prove the importance of viral genotypes in causing severe epidemics. The influence of host immune status and mosquito vectorial capacity are also being tested in mathematical models to determine virus population dynamics. Therefore, new technologies are allowing us to better understand how specific virus variants cause more disease than others, and these virus variants should be targeted for detection, control, and treatment. PMID:17479944

  18. Optimal Repellent Usage to Combat Dengue Fever.

    PubMed

    Dorsett, Chasity; Oh, Hyunju; Paulemond, Marie Laura; Rychtář, Jan

    2016-05-01

    Dengue fever is one of the most important vector-borne diseases. It is transmitted by Aedes Stegomyia aegypti, and one of the most effective strategies to combat the disease is the reduction of exposure to bites of these mosquitoes. In this paper, we present a game-theoretical model in which individuals choose their own level of protection against mosquito bites in order to maximize their own benefits, effectively balancing the cost of protection and the risk of contracting the dengue fever. We find that even when the usage of protection is strictly voluntary, as soon as the cost of protection is about 10,000 times less than the cost of contracting dengue fever, the optimal level of protection will be within 5 % of the level needed for herd immunity.

  19. Hepatitis and thrombocytopenia: markers of dengue mortality.

    PubMed

    Krishnamoorthy, Smitha; Bhatt, Arun N; Mathew, Celine Thalappillil; Ittyachen, Abraham M

    2017-04-01

    Dengue fever is of great concern to public health in India as it contributes significantly to the burden of healthcare. The aim of our study was to measure mortality in dengue and its association with hepatitis and thrombocytopenia. Our study was performed in a tertiary care setting in the state of Kerala in southern India. Adult patients admitted in the year 2013 were included. Among 1308 confirmed dengue patients, the mortality rate was 1.76%. Hepatitis and thrombocytopenia were present in over 80% of all patients, but severe hepatitis was seen in 11.4% and severe thrombocytopenia in 9.3%. These were markers of fatal outcome. Other factors significantly associated with mortality were age >60 years, male sex, diabetes and the presence of any co-morbidity.

  20. [Imported dengue: an emerging arbovirosis in Spain].

    PubMed

    Ramos Geldres, T T; García López-Hortelano, M; Baquero-Artigao, F; Montero Vega, D; López Quintana, B; Mellado Peña, M J

    2015-01-01

    Dengue is caused by one of 4 serotypes of dengue virus. Only imported cases have been reported in Spain. The main clinical findings are fever and exanthema, although there may be severe forms, particularly in secondary infections. Five children with a primary, non severe dengue infection are presented. The diagnosis was based on clinical suspicion and epidemiological history, and confirmed by immunochromatography and ELISA tests. The outcome was favourable in all cases. It is important to consider this diagnosis in international travellers that present with fever within the 14 days of returning from an endemic area, in order to get an early diagnosis, adequate treatment and a good prognosis. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  1. Dengue vaccines: challenges, development, current status and prospects.

    PubMed

    Ghosh, A; Dar, L

    2015-01-01

    Infection with dengue virus (DENV) is the most rapidly spreading mosquito-borne viral disease in the world. The clinical spectrum of dengue, caused by any of the four serotypes of DENV, ranges from mild self-limiting dengue fever to severe dengue, in the form dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Increased rates of hospitalization due to severe dengue, during outbreaks, result in massive economic losses and strained health services. In the absence of specific antiviral therapy, control of transmission of DENV by vector management is the sole method available for decreasing dengue-associated morbidity. Since vector control strategies alone have not been able to satisfactorily achieve reduction in viral transmission, the implementation of a safe, efficacious and cost-effective dengue vaccine as a supplementary measure is a high public health priority. However, the unique and complex immunopathology of dengue has complicated vaccine development. Dengue vaccines have also been challenged by critical issues like lack of animal models for the disease and absence of suitable markers of protective immunity. Although no licensed dengue vaccine is yet available, several vaccine candidates are under phases of development, including live attenuated virus vaccines, live chimeric virus vaccines, inactivated virus vaccines, subunit vaccines, DNA vaccines and viral-vectored vaccines. Although some vaccine candidates have progressed from animal trials to phase II and III in humans, a number of issues regarding implementation of dengue vaccine in countries like India still need to be addressed. Despite the current limitations, collaborative effects of regulatory bodies like World Health Organization with vaccine manufacturers and policy makers, to facilitate vaccine development and standardize field trials can make a safe and efficacious dengue vaccine a reality in near future.

  2. Research on Climate and Dengue in Malaysia: A Systematic Review.

    PubMed

    Hii, Yien Ling; Zaki, Rafdzah Ahmad; Aghamohammadi, Nasrin; Rocklöv, Joacim

    2016-03-01

    Dengue is a climate-sensitive infectious disease. Climate-based dengue early warning may be a simple, low-cost, and effective tool for enhancing surveillance and control. Scientific studies on climate and dengue in local context form the basis for advancing the development of a climate-based early warning system. This study aims to review the current status of scientific studies in climate and dengue and the prospect or challenges of such research on a climate-based dengue early warning system in a dengue-endemic country, taking Malaysia as a case study. We reviewed the relationship between climate and dengue derived from statistical modeling, laboratory tests, and field studies. We searched electronic databases including PubMed, Scopus, EBSCO (MEDLINE), Web of Science, and the World Health Organization publications, and assessed climate factors and their influence on dengue cases, mosquitoes, and virus and recent development in the field of climate and dengue. Few studies in Malaysia have emphasized the relationship between climate and dengue. Climatic factors such as temperature, rainfall, and humidity are associated with dengue; however, these relationships were not consistent. Climate change projections for Malaysia show a mounting risk for dengue in the future. Scientific studies on climate and dengue enhance dengue surveillance in the long run. It is essential for institutions in Malaysia to promote research on climate and vector-borne diseases to advance the development of climate-based early warning systems. Together, effective strategies that improve existing research capacity, maximize the use of limited resources, and promote local-international partnership are crucial for sustaining research on climate and health.

  3. Cost of dengue outbreaks: literature review and country case studies

    PubMed Central

    2013-01-01

    Background Dengue disease surveillance and vector surveillance are presumed to detect dengue outbreaks at an early stage and to save – through early response activities – resources, and reduce the social and economic impact of outbreaks on individuals, health systems and economies. The aim of this study is to unveil evidence on the cost of dengue outbreaks. Methods Economic evidence on dengue outbreaks was gathered by conducting a literature review and collecting information on the costs of recent dengue outbreaks in 4 countries: Peru, Dominican Republic, Vietnam, and Indonesia. The literature review distinguished between costs of dengue illness including cost of dengue outbreaks, cost of interventions and cost-effectiveness of interventions. Results Seventeen publications on cost of dengue showed a large range of costs from 0.2 Million US$ in Venezuela to 135.2 Million US$ in Brazil. However, these figures were not standardized to make them comparable. Furthermore, dengue outbreak costs are calculated differently across the publications, and cost of dengue illness is used interchangeably with cost of dengue outbreaks. Only one paper from Australia analysed the resources saved through active dengue surveillance. Costs of vector control interventions have been reported in 4 studies, indicating that the costs of such interventions are lower than those of actual outbreaks. Nine papers focussed on the cost-effectiveness of dengue vaccines or dengue vector control; they do not provide any direct information on cost of dengue outbreaks, but their modelling methodologies could guide future research on cost-effectiveness of national surveillance systems. The country case studies – conducted in very different geographic and health system settings - unveiled rough estimates for 2011 outbreak costs of: 12 million US$ in Vietnam, 6.75 million US$ in Indonesia, 4.5 million US$ in Peru and 2.8 million US$ in Dominican Republic (all in 2012 US$). The proportions of the

  4. Understanding dengue pathogenesis: implications for vaccine design.

    PubMed Central

    Stephenson, John R.

    2005-01-01

    In the second half of the twentieth century dengue spread throughout the tropics, threatening the health of a third of the world's population. Dengue viruses cause 50-100 million cases of acute febrile disease every year, including more than 500,000 reported cases of the severe forms of the disease--dengue haemorrhagic fever and dengue shock syndrome. Attempts to create conventional vaccines have been hampered by the lack of suitable experimental models, the need to provide protection against all four serotypes simultaneously and the possible involvement of virus-specific immune responses in severe disease. The current understanding of dengue pathogenesis is outlined in this review, with special emphasis on the role of the immune response. The suspected involvement of the immune system in increased disease severity and vascular damage has raised concerns about every vaccine design strategy proposed so far. Clearly more research is needed on understanding the correlates of protection and mechanisms of pathogenesis. There is, however, an urgent need to provide a solution to the escalating global public health problems caused by dengue infections. Better disease management, vector control and improved public health measures will help reduce the current disease burden, but a safe and effective vaccine is probably the only long-term solution. Although concerns have been raised about the possible safety and efficacy of both conventional and novel vaccine technologies, the situation is now so acute that it is not possible to wait for the perfect vaccine. Consequently the careful and thorough evaluation of several of the current candidate vaccines may be the best approach to halting the spread of disease. PMID:15868023

  5. [Epidemiological dynamics of Dengue on Easter Island].

    PubMed

    Canals, Mauricio; González, Christian; Canals, Andrea; Figueroa, Daniela

    2012-08-01

    Dengue is considered an emerging disease with an increasing prevalence especially in South America. In 2002, an epidemic of classic Dengue (DENV-1) occurred unexpectedly on Easter Island, where it had never been detected before. It reappeared in 2006-2007 and 2008, 2009 and 2011. The aim of this study was to estimate the most relevant parameters of the epidemiological dynamics of transmission of Dengue on Easter Island and to model the dynamics since 2002, comparing the predictions with the actual situation observed. Of the total cases, 52.27% were females and 47.73% men. The average age of infection was 31.38 ± 18.37 years, similar in men and women. We estimated the reproductive number R0 = 3.005 with an IC0,95 = [1.92, 4.61]. The inter-epidemic period reached an estimated T = 5.20 to 6.8 years. The case simulation showed recurrent epidemics with decreasing magnitude (damped oscillations), which is a known phenomenon in models of dengue and malaria. There was good qualitative fit to the epidemiological dynamics from 2002 onwards. It accurately predicted the rise in cases between 2006 and 2011. The predicted number of cases during the 2002 epidemic is greater than the confirmed cases and the predicted epidemic was faster than notified cases. Interepidemic period in the simulation was 6.72 years between 2002 and 2008 and 4.68 years between 2008 and 2013. From the theoretical perspective, the first epidemic had affected 94% of the population (approximately 3500 cases), but 639 were reported suggesting underreporting and a lot of sub-clinical cases occurred. Future epidemic of decreasing size are expected, although the main danger are epidemics of hemorrhagic dengue fever resulting from the introduction of different dengue virus serotypes.

  6. Sensorineural hearing loss in hemorrhagic dengue?

    PubMed Central

    Ribeiro, Bruna Natália Freire; Guimarães, Alexandre Caixeta; Yazawa, Felipe; Takara, Tammy Fumiko Messias; de Carvalho, Guilherme Machado; Zappelini, Carlos Eduardo Monteiro

    2014-01-01

    Introduction Dengue is an acute febrile infectious disease, with high fever followed by symptoms flu-like. Dengue hemorrhagic fever (DHF) is a vascular leak syndrome and could present spontaneous bleeding and worsening of symptoms after some days. Dengue could have some ENT manifestations, however hearing loss is not one of them. Sudden hearing loss is considered as sensorineural or perceptual hearing loss with a sudden onset in a person without other prior otological history. The relation between infectious diseases and sudden hearing are been investigated, some viruses were already linked, but the relation between dengue virus and sudden hearing still remains unknown. This article has the goal of presenting a case of DHF that evolved with SSHL in his hospitalization process. Presentation of case We report a 60 years-male patient of with DHF who developed bilateral secretory otitis media and sensorineural hearing loss after the fifth day of onset of symptoms. His hearing loss remained even after 7 months and the patient was referred for hearing aid fitting. Discussion and conclusion This is the first case report that brings together DHF and sudden hearing loss. In the development of this case no other cause to sudden hearing loss was found and the correlation between dengue and hearing loss was questioned. In the literature review was found that some viruses, as mumps virus, varicella-zoster virus and HSV-1 and HSV-2 are related to sudden hearing loss, all of them fit in the viral theory. Besides the viral theory of sudden hearing loss, there is the vascular theory that is the occlusion of the end artery that supplies the cochlea. DHF has a vascular commitment, and the hypothesis of a vascular cause could be elicited in this case. Many studies in this area are needed and this article has the objective of elicit the discussion about the subject. Could dengue be associated with sensorineural hearing loss? PMID:25625489

  7. T cell responses and dengue haemorrhagic fever.

    PubMed

    Screaton, Gavin; Mongkolsapaya, Juthathip

    2006-01-01

    The enhancement of severe disease upon secondary infection makes dengue almost unique among infectious pathogens and presents a serious challenge to vaccine design. Several key observations have been made which shed light onto this phenomenon particularly that antibodies can enhance Fc receptor-dependent uptake of virus into macrophages thereby increasing virus replication. Furthermore there seems to be a relationship between the peak virus load and disease severity. However, a second key feature of dengue is that the life-threatening symptoms do not correlate with the period of high viraemia; instead they occur at a time when the virus load is in steep decline. The coincidence of severe disease manifestations with defervescence and virus control suggests that the symptoms may be a consequence of the immune response to the virus rather than virus induced cytopathology. One of the key elements in the immune response to viruses are T cells which can both secrete a host of inflammatory cytokines and also be directly cytotoxic to infected cells. There are a number of experimental models of T cell-induced immunopathology including in responses to viruses. Particularly interesting in this respect are models of RSV-induced immunopathology, which have direct relevance to vaccine design as a formalin-inactivated vaccine to RSV actually enhanced disease in children when they became naturally infected with RSV, an echo of the disease enhancement seen in dengue. We will present an analysis of CD8+ T cell responses to a number of novel T cell epitopes during dengue infection and also analyse the function and cytokine secretion of these cells. We suggest that an exaggerated and partially misdirected T cell response seen in secondary dengue infection may be part of the complex series of events leading to dengue haemorrhagic fever and shock.

  8. Cost-effectiveness of dengue vaccination in Yucatán, Mexico using a dynamic dengue transmission model.

    PubMed

    Shim, Eunha

    2017-01-01

    The incidence of dengue fever (DF) is steadily increasing in Mexico, burdening health systems with consequent morbidities and mortalities. On December 9th, 2015, Mexico became the first country for which the dengue vaccine was approved for use. In anticipation of a vaccine rollout, analysis of the cost-effectiveness of the dengue vaccination program that quantifies the dynamics of disease transmission is essential. We developed a dynamic transmission model of dengue in Yucatán, Mexico and its proposed vaccination program to incorporate herd immunity into our analysis of cost-effectiveness analysis. Our model also incorporates important characteristics of dengue epidemiology, such as clinical cross-immunity and susceptibility enhancement upon secondary infection. Using our model, we evaluated the cost-effectiveness and economic impact of an imperfect dengue vaccine in Yucatán, Mexico. Our study indicates that a dengue vaccination program would prevent 90% of cases of symptomatic DF incidence as well as 90% of dengue hemorrhagic fever (DHF) incidence and dengue-related deaths annually. We conclude that a dengue vaccine program in Yucatán, Mexico would be very cost-effective as long as the vaccination cost per individual is less than $140 and $214 from health care and societal perspectives, respectively. Furthermore, at an exemplary vaccination cost of $250 USD per individual on average, dengue vaccination is likely to be cost-effective 43% and 88% of the time from health care and societal perspectives, respectively.

  9. Human botfly larva in a child's scalp.

    PubMed

    Liebert, Peter S; Madden, Robert C

    2004-04-01

    The botfly is the name for several families of hairy flies the larvae of which live as parasites in the bodies of mammals. Reported are the presentation, diagnosis, and noninvasive therapy for a botfly larva in the scalp of a 14 year old.

  10. Workbook on Identification of Aedes Aegypti Larvae.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; And Others

    This self-instructional booklet is designed to enable yellow fever control workers to identify the larvae of "Aedes aegypti." The morphological features of mosquito larvae are illustrated in this partially programed text, and the distinguishing features of "A. aegypti" indicated. A glossary is included. (AL)

  11. An evaluation of some Trinidadian plant extracts against larvae of Aedes aegypti mosquitoes.

    PubMed

    Mohammed, Azad; Chadee, Dave D

    2007-06-01

    In recent times, bioprospecting for plants that show bioactive properties has yielded many chemicals that can be used in controlling mosquitoes. Crude extracts of 4 terrestrial and 3 mangrove plants were assayed against 2-3 larval instars of Aedes aegypti. Among the plants tested, Cordia curassavica showed the highest levels of activity for all the extracts tested. Azadirachta indica showed the least activity, whereas the 2 cultivars of Mangifera indica showed substantial activity for the aqueous extracts. The mangrove species proved to be relatively nontoxic to Ae. aegypti larvae when compared to the terrestrial plants. The results of this study suggest that some common plants in Trinidad may be highly effective in controlling the urban vector of yellow fever and dengue fever, Ae. aegypti.

  12. Pathogenesis of Dengue Vaccine Viruses in Mosquitoes.

    DTIC Science & Technology

    1984-01-01

    type 2 (Price, 1973), and attenuated Japanese encephalitis vaccine virus (Chen and Beaty, 1982). Sabin (1948) showed that attenuated dengue virus...M194 992 PATHOGENESIS OF DENGUJE VACCINE VIRUSES IN NOSSUITOES vi1 (u) COLORADO STATE UNIV FORT COLLINS DEPT OF MICROBIOLOGY AND ENVIRONMENTAL...IW AV wWW W N A A~~ Nq .. mcFILE COPY 0)0 AD PATHOGENESIS OF DENGUE VACCINE VIRUSES IN MOSQUITOES Annual Report Barry J. Beaty, Ph.D. D T IC ELECTE

  13. Egg and fourth instar larvae gut of Aedes aegypti as a source of stem cells.

    PubMed

    Mario, Lara C; Borghesi, Jéssica; Crivellari-Damasceno, Wilson T; Favaron, Phelipe O; Carreira, Ana Claudia O; Will, Sonia E A L; Maria, Durvanei A; Miglino, Maria A

    2016-10-01

    According to the World Health Organization, 2015 registered more than 1.206.172 cases of Dengue in the Americas. Recently, the Aedes aegypti has been not only related to Dengue, but also with cases of Zika virus and Chikungunya. Due to its epidemiological importance, this study characterized the morphology of the embryonated eggs of A. aegypti and provided a protocol to culture stem cells from eggs and digestive tract of fourth instar larvae in order to examine cell biology and expression of markers in these vectors. Cells were isolated and cultured in DMEM-High at 28°C, and their morphology, cell cycle and immunophenotyping were examined. Morphologically, embryos were at the end of the embryonic period and showed: head, thorax, and abdomen with eight abdominal segments. The embryonic tissues expressed markers related to cell proliferation (PCNA), pluripotency (Sox2 and OCT3/4), neural cells (Nestin), mesenchymal cells (Vimentin and Stro-1), and endosomal cells (GM130 and RAB5). In culture, cells from both tissues (eggs and larvae gut) were composed by a heterogeneous population. The cells had a globoid shape and small size. Cell cycle analysis on passage 1 (P1) showed 27.5%±2.0% of cell debris, 68% of cells on G0-G1 phase, 30.2% on S phase, 1.9%±0.5% on G2-M phase. In addition, cells on passage 2 showed: 10% of cell debris, 92.4% of cells on G0-G1 phase, 6.8% on S phase, 0.6% on G2-M phase. Embryonated eggs expressed markers involved with pluripotency (Sox2 and Oct 3/4), mesenchymal cells (vimentin and Stro-1), neural cells (Nestin), and cellular death by apoptosis (Caspase 3). Specific endosomal markers for insect cells (GM130 and RAB5) were also highly expressed. In cell culture of A. aegypti larvae gut the same labeling pattern was observed, with a small decrease in the expression of mesenchymal (vimentin and Stro-1) and neural (Nestin) markers. In summary, we were able to establish a protocol to culture embryonated eggs and larvae gut of A. aegypti

  14. Physiological and Morphological Aspects of Aedes aegypti Developing Larvae: Effects of the Chitin Synthesis Inhibitor Novaluron

    PubMed Central

    Farnesi, Luana C.; Brito, José M.; Linss, Jutta G.; Pelajo-Machado, Marcelo; Valle, Denise; Rezende, Gustavo L.

    2012-01-01

    Population control of the dengue vector mosquito, Aedes aegypti, is difficult due to many reasons, one being the development of resistance to neurotoxic insecticides employed. The biosynthesis of chitin, a major constituent of insect cuticle, is a novel target for population control. Novaluron is a benzoylphenylurea (BPU) that acts as a chitin synthesis inhibitor, already used against mosquitoes. However, information regarding BPU effects on immature mosquito stages and physiological parameters related with mosquito larval development are scarce. A set of physiological parameters were recorded in control developing larvae and novaluron was administered continuously to Ae. aegypti larvae, since early third instar. Larval instar period duration was recorded from third instar until pupation. Chitin content was measured during third and fourth instars. Fourth instars were processed histochemically at the mesothorax region, stained with hematoxylin and eosin (HE) for assessment of internal tissues, and labeled with WGA-FITC to reveal chitinized structures. In control larvae: i) there is a chitin content increase during both third and fourth instars where late third instars contain more chitin than early fourth instars; ii) thoracic organs and a continuous cuticle, closely associated with the underlying epidermis were observed; iii) chitin was continuously present throughout integument cuticle. Novaluron treatment inhibited adult emergence, induced immature mortality, altered adult sex ratio and caused delay in larval development. Moreover, novaluron: i) significantly affected chitin content during larval development; ii) induced a discontinuous and altered cuticle in some regions while epidermis was often thinner or missing; iii) rendered chitin cuticle presence discontinuous and less evident. In both control and novaluron larvae, chitin was present in the peritrophic matrix. This study showed quantitatively and qualitatively evidences of novaluron effects on Ae

  15. Why are people with dengue dying? A scoping review of determinants for dengue mortality.

    PubMed

    Carabali, Mabel; Hernandez, Libia Milena; Arauz, Maria Jose; Villar, Luis Angel; Ridde, Valéry

    2015-07-30

    Dengue is a viral disease whose clinical spectrum ranges from unapparent to severe forms and fatal outcomes. Although dengue death is 99% avoidable, every year around 20,000 deaths are estimated to occur in more than 100 countries. We consider that, along with biological factors, social determinants of health (SDHs) are related to dengue deaths as well. A scoping review was conducted to explore what has been written about the role of SDHs in dengue mortality. The inclusion criteria were that documents (grey or peer-reviewed) had to include information about dengue fatal cases in humans and be published between 1997 and 2013 and written in English, Spanish, Portuguese or French. The search was conducted using a set of key words related to dengue mortality in several electronic databases: PubMed, LILACS, COCHRANE, Scielo, Science Direct, WHOLIS, OpenGrey, OpenSingle and Google Scholar. Information on SDHs was categorized under individual, social and environmental, and health systems dimensions. A summative content analysis using QDA Miner was conducted to assess the frequency of information on SDHs and its contextual meaning in the reviewed literature. The role of each SDH in dengue mortality was assessed using content analysis results. From a total of 971 documents retrieved, 78 met the criteria. Those documents were published in the Americas region (50.0%), Asia (38.4%), Europe (9.0%) and Africa (2.6%). The described SDHs related to dengue deaths included, in the individual dimension: age, ethnicity, education, type of infection and immunological status; and in the social dimension: poverty and care-seeking behavior. The health systems dimension included access, opportunity, and quality of care, as well as health staff knowledge. Ethnicity was considered a determinant that depends on cultural and socioeconomic conditions. Along with biological factors, there are several SDHs related to dengue mortality. However, only a few of these have been systematically analyzed

  16. Characterization of the 2013 dengue epidemic in Myanmar with dengue virus 1 as the dominant serotype.

    PubMed

    Ngwe Tun, Mya Myat; Kyaw, Aung Kyaw; Makki, Nader; Muthugala, Rohitha; Nabeshima, Takeshi; Inoue, Shingo; Hayasaka, Daisuke; Moi, Meng Ling; Buerano, Corazon C; Thwe, Saw Myat; Thant, Kyaw Zin; Morita, Kouichi

    2016-09-01

    In 2013 in Myanmar, dengue epidemic occurred with 20,255 cases including 84 deaths. This study aimed to determine the serological and molecular characteristics of dengue virus (DENV) infection among children with clinical diagnosis of dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS) during this period. Single acute serum samples were collected from 300 children in Mandalay Children Hospital, Mandalay, Myanmar. Out of the 300 children, 175 (58.3%) and 183 (61%) were positive for anti-dengue IgM and anti-dengue IgG, respectively. Among the IgM positives, 41 (23.4%) had primary DENV infection. Thirty-nine DENV strains (23 DENV-1, 10 DENV-2 and 6 DENV-4) were successfully isolated after inoculation of the patient serum samples onto C6/36 cells. DENV 1 was the dominant serotype in the 2013 epidemic. There was no correlation between the infecting serotypes and clinical severities. The DENV-1 strains belonged to three lineages of the genotype 1; the DENV-2 strains were of the Asian I genotype and were separated into two lineages; and DENV-4 strains belonged to the same lineage of genotype I. It is of interest to note the diversity of DENV-1 and -2 circulating in the same location during June-August 2013. These DENV isolates were genetically close (98%-100%) to the other previously reported isolates from Myanmar and its neighboring countries, namely China, Thailand, Sri Lanka, Cambodia and Vietnam. Primary DENV infection was still high among the severe dengue cases. Different serotypes of DENV were co-circulating in 2013, however, genotype shift was not observed. Additionally, amino acid mutations were detected in the study strains not seen in the previously reported strains from other countries and Myanmar. This paper provided information on the circulating serotypes for the last 15years and the recent dengue situation in Mandalay, Myanmar after 2006. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Complete Genome Sequence of a Dengue Virus Serotype 4 Strain Isolated in Roraima, Brazil

    PubMed Central

    Souza, Victor C.; Silva, George A. V.; Maito, Rodrigo M.; Granja, Fabiana; Siqueira, Thalita; Acosta, Pablo O. A.

    2012-01-01

    Dengue is the most important arboviral disease worldwide. We report the complete genome sequence of a dengue virus serotype 4, genotype II strain isolated in 2010 from a patient with classical dengue fever in Boa Vista, Roraima, Brazil. PMID:22247521

  18. Transstadial Effects of Bti on Traits of Aedes aegypti and Infection with Dengue Virus

    PubMed Central

    Alto, Barry W.; Lord, Cynthia C.

    2016-01-01

    Most mosquito control efforts are primarily focused on reducing the adult population size mediated by reductions in the larval population, which should lower risk of disease transmission. Although the aim of larviciding is to reduce larval abundance and thus recruitment of adults, nonlethal effects on adults are possible, including transstadial effects on phenotypes of adults such as survival and pathogen infection and transmission. In addition, the mortality induced by control efforts may act in conjunction with other sources of mosquito mortality in nature. The consequences of these effects and interactions may alter the potential of the population to transmit pathogens. We tested experimentally the combined effects of a larvicide (Bacillus thuringiensis ssp. israelensis, Bti) and competition during the larval stages on subsequent Aedes aegypti (Linnaeus) traits, population performance, and susceptibility to dengue-1 virus infection. Ae. aegypti that survived exposure to Bti experienced accelerated development, were larger, and produced more eggs with increasing amounts of Bti, consistent with competitive release among surviving mosquitoes. Changing larval density had no significant interactive effect with Bti treatment on development and growth to adulthood. Larval density, but not Bti or treatment interaction, had a strong effect on survival of adult Ae. aegypti females. There were sharper declines in cumulative daily survival of adults from crowded than uncrowded larval conditions, suggesting that high competition conditions of larvae may be an impediment to transmission of dengue viruses. Rates of infection and dengue-1 virus disseminated infections were found to be 87±13% and 88±12%, respectively. There were no significant treatment effects on infection measurements. Our findings suggest that larvicide campaigns using Bti may reduce the number of emerged adults, but survivors will have a fitness advantage (growth, development, enhanced production of eggs

  19. Natural vertical transmission of dengue viruses in Aedes aegypti in selected sites in Cebu City, Philippines.

    PubMed

    Edillo, Frances E; Sarcos, Janet R; Sayson, Stephanie L

    2015-12-01

    We attempted to determine the vertical transmission of dengue virus (DENV) in Aedes aegypti in selected sites in Cebu City, Philippines. Mosquito sub-adults were collected monthly from households and the field during the wet-dry-wet season from November, 2011 to July, 2012 and were laboratory-reared to adults. Viral RNA extracts in mosquitoes were assayed by hemi-nested RT-PCR. Results showed that 62 (36.26%; n=679) out of 171 mosquito pools (n=2,871) were DENV+. The minimum infection rate (MIR) of DENV ranged from 0 in wet months to 48.22/1,000 mosquitoes in April, 2012 (mid-dry). DENVs were detected in larvae, pupae, and male and female adults, with DENV-4, DENV-3, and DENV-1, in that rank of prevalence. DENV-1 co-infected with either DENV-3 or -4 or with both in April, 2012; DENV-3 and -4 were present in both seasons. More DENV+ mosquitoes were collected from households than in field premises (p<0.001) and in the dry than in the wet season (p<0.05), with significant interaction (p<0.05) between sites and premises but no interaction between sites and seasons (p>0.05). By Generalized Linear Mixed models, the type of premises nested in sites and monthly total rainfall were significant predictors of monthly dengue cases (p<0.05) and not MIR, season, temperature, and relative humidity. Surveillance of DENV prevalence in Ae. aegypti and detecting their natural foci in the dry season provide an early warning signal of dengue outbreak. © 2015 The Society for Vector Ecology.

  20. The CNS connectome of a tadpole larva of Ciona intestinalis (L.) highlights sidedness in the brain of a chordate sibling.

    PubMed

    Ryan, Kerrianne; Lu, Zhiyuan; Meinertzhagen, Ian A

    2016-12-06

    Left-right asymmetries in brains are usually minor or cryptic. We report brain asymmetries in the tiny, dorsal tubular nervous system of the ascidian tadpole larva, Ciona intestinalis. Chordate in body plan and development, the larva provides an outstanding example of brain asymmetry. Although early neural development is well studied, detailed cellular organization of the swimming larva's CNS remains unreported. Using serial-section EM we document the synaptic connectome of the larva's 177 CNS neurons. These formed 6618 synapses including 1772 neuromuscular junctions, augmented by 1206 gap junctions. Neurons are unipolar with at most a single dendrite, and few synapses. Some synapses are unpolarised, others form reciprocal or serial motifs; 922 were polyadic. Axo-axonal synapses predominate. Most neurons have ciliary organelles, and many features lack structural specialization. Despite equal cell numbers on both sides, neuron identities and pathways differ left/right. Brain vesicle asymmetries include a right ocellus and left coronet cells.

  1. Serological characterization of dengue virus infections observed among dengue hemorrhagic fever/dengue shock syndrome cases in upper Myanmar.

    PubMed

    Ngwe Tun, Mya Myat; Thant, Kyaw Zin; Inoue, Shingo; Kurosawa, Yae; Lwin, Yee Yee; Lin, Sanda; Aye, Kay Thi; Thet Khin, Pe; Myint, Tin; Htwe, Khin; Mapua, Cynthia A; Natividad, Filipinas F; Hirayama, Kenji; Morita, Kouichi

    2013-07-01

    In Myanmar, dengue fever (DF)/dengue hemorrhagic fever (DHF) is one of the leading causes of morbidity and mortality among children. From Pyinmana Hospital in 2004 and Mandalay Children Hospital in 2006, 160 patients diagnosed clinically to have DHF/dengue shock syndrome (DSS) were examined for immunoglobulin M (IgM) and IgG levels. A focus reduction neutralization test was also used to determine primary or secondary dengue virus (DENV) infection. By using IgM-capture ELISA, 139 cases were confirmed as DENV infections. Of these IgM-positives, 94 samples were collected 7-24 days from the onset of illness, to which 13 (14%) and 81 (86%) were determined to be primary and secondary DENV infections, respectively. The 13 primary DENV infection cases were spread among the various severity groups (DHF grade I-IV and DSS) and represented age groups ranging from <1 year of age to 9 years of age. The patients in these primary infection cases showed a remarkably high IgM with a low IgG titer response compared with the secondary infection cases. No significant differences were observed in IgG titers with clinical severity. The data obtained in this study suggest that primary DENV infection cases exist certainly among DHF/DSS cases in Myanmar, and that additional mechanism(s) aside from the antibody-dependent enhancement mechanism could have influenced the clinical severity in DHF/DSS cases.

  2. DengueME: A Tool for the Modeling and Simulation of Dengue Spatiotemporal Dynamics †

    PubMed Central

    de Lima, Tiago França Melo; Lana, Raquel Martins; de Senna Carneiro, Tiago Garcia; Codeço, Cláudia Torres; Machado, Gabriel Souza; Ferreira, Lucas Saraiva; de Castro Medeiros, Líliam César; Davis Junior, Clodoveu Augusto

    2016-01-01

    The prevention and control of dengue are great public health challenges for many countries, particularly since 2015, as other arboviruses have been observed to interact significantly with dengue virus. Different approaches and methodologies have been proposed and discussed by the research community. An important tool widely used is modeling and simulation, which help us to understand epidemic dynamics and create scenarios to support planning and decision making processes. With this aim, we proposed and developed DengueME, a collaborative open source platform to simulate dengue disease and its vector’s dynamics. It supports compartmental and individual-based models, implemented over a GIS database, that represent Aedes aegypti population dynamics, human demography, human mobility, urban landscape and dengue transmission mediated by human and mosquito encounters. A user-friendly graphical interface was developed to facilitate model configuration and data input, and a library of models was developed to support teaching-learning activities. DengueME was applied in study cases and evaluated by specialists. Other improvements will be made in future work, to enhance its extensibility and usability. PMID:27649226

  3. [Dengue virus serotype 1 (DENV-1) from Colombia: its contribution to dengue occurrence in Santander].

    PubMed

    Ocazionez-Jiménez, Raquel E; Ortiz-Báez, Ayda Susana; Gómez-Rangel, Sergio Yebrail; Miranda-Esquivel, Daniel R

    2013-09-01

    Between 1998 and 2008 all dengue virus serotypes circulated in the Departamento de Santander, an endemic region in northeastern Colombia. No information is available as to the role of serotype 1 (DENV-1) with respect to epidemiology of dengue. To analyze the relationship between changes in DENV-1 predominance with respect to genetic diversity, prevalence of others serotypes and occurrence of severe dengue. Virus genetic diversity was studied by phylogenetic analysis comparing E gene sequences from 12 viral strains. Data about serotypes predominance obtained in previous studies and official data about dengue incidence were used for analysis. Selected viruses grouped into genotype V together DENV-1 from Latin America countries, and segregation in four lineages was evidenced. Changes in virus predominance coincided with replacement of lineage, increase in prevalence of DENV-2 and DENV-3 and increase of severe dengue. Genetic divergence could have contributed to changes in DENV-1 predominance. The relationship of the virus with DENV-2 and DENV-3 could create scenarios that promote occurrence of severe cases. More studies are required to ascertain the precise role of serotypes in the epidemiology of dengue.

  4. DengueME: A Tool for the Modeling and Simulation of Dengue Spatiotemporal Dynamics.

    PubMed

    de Lima, Tiago França Melo; Lana, Raquel Martins; de Senna Carneiro, Tiago Garcia; Codeço, Cláudia Torres; Machado, Gabriel Souza; Ferreira, Lucas Saraiva; de Castro Medeiros, Líliam César; Davis Junior, Clodoveu Augusto

    2016-09-15

    The prevention and control of dengue are great public health challenges for many countries, particularly since 2015, as other arboviruses have been observed to interact significantly with dengue virus. Different approaches and methodologies have been proposed and discussed by the research community. An important tool widely used is modeling and simulation, which help us to understand epidemic dynamics and create scenarios to support planning and decision making processes. With this aim, we proposed and developed DengueME, a collaborative open source platform to simulate dengue disease and its vector's dynamics. It supports compartmental and individual-based models, implemented over a GIS database, that represent Aedes aegypti population dynamics, human demography, human mobility, urban landscape and dengue transmission mediated by human and mosquito encounters. A user-friendly graphical interface was developed to facilitate model configuration and data input, and a library of models was developed to support teaching-learning activities. DengueME was applied in study cases and evaluated by specialists. Other improvements will be made in future work, to enhance its extensibility and usability.

  5. Indirect effects of cigarette butt waste on the dengue vector Aedes aegypti (Diptera: Culicidae).

    PubMed

    Dieng, Hamady; Rajasaygar, Sudha; Ahmad, Abu Hassan; Rawi, Che Salmah Md; Ahmad, Hamdan; Satho, Tomomitsu; Miake, Fumio; Zuharah, Wan Fatma; Fukumitsu, Yuki; Saad, Ahmad Ramli; Abdul Hamid, Suhaila; Vargas, Ronald Enrique Morales; Ab Majid, Abdul Hafiz; Fadzly, Nik; Abu Kassim, Nur Faeza; Hashim, Nur Aida; Abd Ghani, Idris; Abang, Fatimah Bt; AbuBakar, Sazaly

    2014-02-01

    Despite major insecticide-based vector control programs, dengue continues to be a major threat to public health in urban areas. The reasons for this failure include the emergence of insecticide resistance and the narrowing of the spectrum of efficient products. Cigarette butts (CBs), the most commonly discarded piece of waste, also represent a major health hazard to human and animal life. CBs are impregnated with thousands of chemical compounds, many of which are highly toxic and none of which has history of resistance in mosquitoes. This study was performed to examine whether exposure to CB alters various biological parameters of parents and their progeny. We examined whether the mosquito changes its ovipositional behaviors, egg hatching, reproductive capacity, longevity and fecundity in response to CB exposure at three different concentrations. Females tended to prefer microcosms containing CBs for egg deposition than those with water only. There were equivalent rates of eclosion success among larvae from eggs that matured in CB and water environments. We also observed decreased life span among adults that survived CB exposure. Extracts of CB waste have detrimental effects on the fecundity and longevity of its offspring, while being attractive to its gravid females. These results altogether indicate that CB waste indirectly affect key adult life traits of Aedes aegypti and could conceivably be developed as a novel dengue vector control strategy, referring to previously documented direct toxicity on the larval stage. But this will require further research on CB waste effects on non-target organisms including humans.

  6. [Dengue-related knowledge, attitudes, and practices in primary schools in Tapachula, Chiapas, Mexico].

    PubMed

    Torres, José Luis; Ordóñez, José Genaro; Vázquez-Martínez, M Guadalupe

    2014-03-01

    To identify dengue-related knowledge, attitudes, and practices among primary school students in Tapachula, Chiapas, Mexico, before and after an educational intervention. The study was carried out at 19 randomly selected public primary schools. Surveys of knowledge, attitudes, and practices were conducted before and after educational sessions with fifthand sixth-grade elementary school students. The educational strategy "Escuelas sin mosquitos" ("Schools without Mosquitoes") emphasized the importance of students' participation in taking care of their schools and homes in order to prevent dengue through vector control. Before and after the educational sessions, a total of 3 124 surveys were conducted on the knowledge, attitudes, and practices of 1 562 fifth and sixth-grade students (772 and 790 students, respectively) between 10 and 12 years of age. The students' level of knowledge was significantly higher after the implementation of the educational strategy. In comparison with the fifth-graders, the sixth-grade students both already had and also acquired significantly more knowledge of several aspects of the disease and the vector. In all the schools, there were containers with water identified as potential breeding sites, and in 68% of the schools, these containers tested positive for Aedes aegypti larvae. It was demonstrated that by implementing an educational strategy, children's knowledge, attitudes, and practices were improved in terms of taking care of their schools and promoting a change of attitude to this disease at home.

  7. Effects of Larval Nutrition on Wolbachia-Based Dengue Virus Interference in Aedes aegypti (Diptera: Culicidae).

    PubMed

    Kho, Elise A; Hugo, Leon E; Lu, Guangjin; Smith, David D; Kay, Brian H

    2016-07-01

    In order to assess the broad-scale applicability of field releases of Wolbachia for the biological control of insect-transmitted diseases, we determined the relationship between the larval diet of Aedes aegypti L. mosquitoes infected with Wolbachia strains and their susceptibility to dengue virus (DENV) infection via intrathoracic injection and oral inoculation. Larvae were reared on diets that varied in the quantity of food which had the effect of modifying development time and adult body size. Wolbachia wMel infection was associated with highly significant reductions in dengue serotype 2 (DENV-2) infection rates of between 80 and 97.5% following intrathoracic injection of adults emerging from three diet levels. Reductions were 100% in two diet level treatments following oral inoculation. Similarly, wMelPop infection was associated with highly significant reductions in DENV-2 infection rates of between 95 and 100% for intrathoracic injection and 97.5 and 100% for oral inoculation across diet level treatments. Larval diet level had no significant effect on DENV-2 infection rates in the presence of Wolbachia infection in mosquitoes that were intrathoracically injected with the virus. This indicates that the effectiveness of Wolbachia on vector competence disruption within Ae. aegypti is unlikely to be compromised by variable larval nutrition in field settings. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Bioefficacy of Mentha piperita essential oil against dengue fever mosquito Aedes aegypti L

    PubMed Central

    Kumar, Sarita; Wahab, Naim; Warikoo, Radhika

    2011-01-01

    Objective To assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant, Mentha piperita (M. piperita) against the larval and adult stages of Aedes aegypti (Ae. Aegypti). Methods The larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae. aegypti using WHO protocol. The mortality counts were made after 24 and 48 h, and LC50 and LC90 values were calculated. The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique. The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol. The mosquito bites on both the arms were recorded for 3 min after every 15 min. The experiment continued for 3 h and the percent protection was calculated. Results The essential oil extracted from M. piperita possessed excellent larvicidal efficiency against dengue vector. The bioassays showed an LC50 and LC90 value of 111.9 and 295.18 ppm, respectively after 24 h of exposure. The toxicity of the oil increased 11.8% when the larvae were exposed to the oil for 48 h. The remarkable repellent properties of M. piperita essential oil were established against adults Ae. aegypti. The application of oil resulted in 100% protection till 150 min. After next 30 min, only 1-2 bites were recorded as compared with 8-9 bites on the control arm. Conclusions The peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector. Further studies are needed to identify the possible role of oil as adulticide, oviposition deterrent and ovicidal agent. The isolation of active ingredient from the oil could help in formulating strategies for mosquito control. PMID:23569733

  9. Bioefficacy of Mentha piperita essential oil against dengue fever mosquito Aedes aegypti L.

    PubMed

    Kumar, Sarita; Wahab, Naim; Warikoo, Radhika

    2011-04-01

    To assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant, Mentha piperita (M. piperita) against the larval and adult stages of Aedes aegypti (Ae. Aegypti). The larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae. aegypti using WHO protocol. The mortality counts were made after 24 and 48 h, and LC50 and LC90 values were calculated. The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique. The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol. The mosquito bites on both the arms were recorded for 3 min after every 15 min. The experiment continued for 3 h and the percent protection was calculated. The essential oil extracted from M. piperita possessed excellent larvicidal efficiency against dengue vector. The bioassays showed an LC50 and LC90 value of 111.9 and 295.18 ppm, respectively after 24 h of exposure. The toxicity of the oil increased 11.8% when the larvae were exposed to the oil for 48 h. The remarkable repellent properties of M. piperita essential oil were established against adults Ae. aegypti. The application of oil resulted in 100% protection till 150 min. After next 30 min, only 1-2 bites were recorded as compared with 8-9 bites on the control arm. The peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector. Further studies are needed to identify the possible role of oil as adulticide, oviposition deterrent and ovicidal agent. The isolation of active ingredient from the oil could help in formulating strategies for mosquito control.

  10. Oviposition preferences of dengue vectors; Aedes aegypti and Aedes albopictus in Sri Lanka under laboratory settings.

    PubMed

    Gunathilaka, N; Ranathunge, T; Udayanga, L; Wijegunawardena, A; Abeyewickreme, W

    2017-09-27

    Investigations on oviposition behaviour of dengue vectors are critical for effective controlling of vector breeding. Therefore, the aim of the present study was to determine the oviposition behaviour of dengue vectors, Aedes aegypti and Aedes albopictus in Sri Lanka. Batches of 1000 adult mosquitoes (1 : 1, male: female ratio) housed in rearing cages were used for each experimental setup from Ae. aegypti and Ae. albopictus. Oviposition responses with respect to the size of the ovitrap, colours of the ovitrap, water source, sodium chloride (NaCl) concentration and presence/absence of larvae were evaluated by enumerating the number of eggs laid in the ovitraps. The analysis of variance and cluster analysis were used to investigate the significance in the variations among oviposition. The number of eggs laid by both species were improved with the increasing size of ovitraps. Ae. albopictus indicated the highest mean number of eggs in 0.2% of NaCl than in the ovitraps filled with distilled water. However, the egg laying preference was reduced with increasing salinity in both species. Drain water with low dissolved oxygen (DO) level (0.43 ± 0.12 mg l-1) was the preferred water source for both species, while a significantly high oviposition rate was observed in ovitraps with larvae. Black colour ovitraps attracted the majority of gravid females, while white was least preferred. There were no significant variations among oviposition behaviours of Ae. albopictus and Ae. aegypti. The ability of these vectors to breed in waste water with low DO levels may lead them to attain wide dissemination in the natural environment, enhancing their potential threat to human life.

  11. Postmortem Diagnosis of Dengue as an Epidemiological Surveillance Tool

    PubMed Central

    de Góes Cavalcanti, Luciano Pamplona; Nunes de Melo Braga, Deborah; Maria Alexandre da Silva, Lívia; Gondim Aguiar, Marina; Castiglioni, Mariana; Silva-Junior, José Udevanier; Montenegro de Carvalho Araújo, Fernanda; Allana da Costa Pereira, Renata; Malta, Danielle Lima; Pompeu, Margarida Maria de Lima

    2016-01-01

    Dengue remains a problem in Brazil, and a substantial number of cases that progress to death are not diagnosed by health services. We evaluated the impact of a protocol adopted by the Coroner's Office Rocha Furtado (CO-RF) for the detection of unreported deaths from dengue in Brazil. We evaluated prospectively cases of deaths referred to the CO-RF with suspicion of dengue and those referred with other diagnosis in which the pathologists suspected dengue as the cause of death. Biological material was collected from all bodies autopsied, for which the suspected cause of death was dengue, between January 2011 and December 2012. Of the 214 bodies autopsied, 134 (62.6%) tested positive for dengue; of these cases, 121 were classified as dengue according to the World Health Organization's case definition (1997 or 2009, as appropriate). Thus, CO-RF detected 90 deaths from dengue, which were not suspected during disease progression. This CO-RF protocol, through a combined effort of the surveillance and laboratory teams, increased the detection of fatal dengue cases by 5-fold. This is the largest series of autopsies performed in cases of death related to dengue in the world to date. PMID:26598561

  12. Cost of Dengue Vector Control Activities in Malaysia

    PubMed Central

    Packierisamy, P. Raviwharmman; Ng, Chiu-Wan; Dahlui, Maznah; Inbaraj, Jonathan; Balan, Venugopalan K.; Halasa, Yara A.; Shepard, Donald S.

    2015-01-01

    Dengue fever, an arbovirus disease transmitted by Aedes mosquitoes, has recently spread rapidly, especially in the tropical countries of the Americas and Asia-Pacific regions. It is endemic in Malaysia, with an annual average of 37,937 reported dengue cases from 2007 to 2012. This study measured the overall economic impact of dengue in Malaysia, and estimated the costs of dengue prevention. In 2010, Malaysia spent US$73.5 million or 0.03% of the country's GDP on its National Dengue Vector Control Program. This spending represented US$1,591 per reported dengue case and US$2.68 per capita population. Most (92.2%) of this spending occurred in districts, primarily for fogging. A previous paper estimated the annual cost of dengue illness in the country at US$102.2 million. Thus, the inclusion of preventive activities increases the substantial estimated cost of dengue to US$175.7 million, or 72% above illness costs alone. If innovative technologies for dengue vector control prove efficacious, and a dengue vaccine was introduced, substantial existing spending could be rechanneled to fund them. PMID:26416116

  13. Internal travel and risk of dengue transmission in Colombia.

    PubMed

    Chaparro, Pablo E; de la Hoz, Fernando; Lozano Becerra, Juan C; Repetto, Silvia A; Alba Soto, Catalina D

    2014-09-01

    Human behavior plays a key role in the dynamics of dengue transmission. However, research on the relationship between human movement and dengue transmission within endemic countries is limited. From January 2008 to December 2011, the authors of this study conducted a retrospective analysis of imported dengue infections in Bogotá, Colombia. Bogotá is a vector-transmission-free city that is also the capital district and most populated municipality in Colombia. The study revealed that 1) Bogotá inhabitants acquired dengue infection in diverse localities throughout the country but the largest proportion of cases (35.6%) were contracted at popular tourist destinations in dengue-endemic areas near Bogotá (<200-km radius from city limits), and 2) the number of imported dengue cases increased after major holidays, a transmission pattern not seen in dengue-endemic areas, where disease incidence correlates with rainy periods. It is therefore recommended that physicians consider the effect of travel when diagnosing their patients' illnesses, especially outside dengue-endemic areas where diagnosis of the disease can be challenging due to its nonspecific symptoms. The study also showed that analysis of dengue cases imported to regions free of vector transmission can generate an evidence-based model for characterizing the impact of human movement on the spread of diseases like dengue in countries where they are endemic.

  14. An innovative forecasting and dashboard system for Malaysian dengue trends

    NASA Astrophysics Data System (ADS)

    Jamil, Jastini Mohd; Shaharanee, Izwan Nizal Mohd

    2016-08-01

    Dengue fever has been recognized in over 100 countries and 2.5 billion people live in areas where dengue is endemic. It is currently a serious arthropod-borne disease, affecting around 50-100 million people worldwide every year. Dengue fever is also prevalent in Malaysia with numerous cases including mortality recorded over the past year. In 2012, a total of 21,900 cases of dengue fever were reported with 35 deaths. Dengue, a mosquito-transmitted virus, causes a high fever accompanied by significant pain in afflicted patient and the Aedes Aegypti mosquito is the primary disease carrier. Knowing the dangerous effect of dengue fever, thus one of the solutions is to implement an innovative forecasting and dashboard system of dengue spread in Malaysia, with emphasize on an early prediction of dengue outbreak. Specifically, the model developed will provide with a valuable insight into strategically managing and controlling the future dengue epidemic. Importantly, this research will deliver the message to health policy makers such as The Ministry of Health Malaysia (MOH), practitioners, and researchers of the importance to integrate their collaboration in exploring the potential strategies in order to reduce the future burden of the increase in dengue transmission cases in Malaysia.

  15. Cost of Dengue Vector Control Activities in Malaysia.

    PubMed

    Packierisamy, P Raviwharmman; Ng, Chiu-Wan; Dahlui, Maznah; Inbaraj, Jonathan; Balan, Venugopalan K; Halasa, Yara A; Shepard, Donald S

    2015-11-01

    Dengue fever, an arbovirus disease transmitted by Aedes mosquitoes, has recently spread rapidly, especially in the tropical countries of the Americas and Asia-Pacific regions. It is endemic in Malaysia, with an annual average of 37,937 reported dengue cases from 2007 to 2012. This study measured the overall economic impact of dengue in Malaysia, and estimated the costs of dengue prevention. In 2010, Malaysia spent US$73.5 million or 0.03% of the country's GDP on its National Dengue Vector Control Program. This spending represented US$1,591 per reported dengue case and US$2.68 per capita population. Most (92.2%) of this spending occurred in districts, primarily for fogging. A previous paper estimated the annual cost of dengue illness in the country at US$102.2 million. Thus, the inclusion of preventive activities increases the substantial estimated cost of dengue to US$175.7 million, or 72% above illness costs alone. If innovative technologies for dengue vector control prove efficacious, and a dengue vaccine was introduced, substantial existing spending could be rechanneled to fund them. © The American Society of Tropical Medicine and Hygiene.

  16. The prevention and control of dengue after Typhoon Haiyan

    PubMed Central

    Aumentado, Charito; Cerro, Boyd Roderick; Olobia, Leonido; Suy, Lyndon Lee; Reyes, Aldrin; Kusumawathie, Pahalagedera HD; Sagrado, Maria; Hall, Julie Lyn; Abeyasinghe, Rabindra; Foxwell, Alice Ruth

    2015-01-01

    Objective Many of the areas in the Philippines affected by Typhoon Haiyan are endemic for dengue; therefore, dengue prevention was a priority in the initial post-disaster risk assessment. We describe the dengue prevention and response strategies applied after Haiyan. Methods The dengue response was implemented by a wide range of national and international stakeholders. Priorities included the rapid re-establishment of an effective surveillance system to quickly identify new dengue cases, monitor trends and determine the geographical distribution of cases. Dengue rapid diagnostic tests (RDTs) were distributed to sentinel health facilities, and comprehensive vector control activities and entomological surveys were implemented. Several training sessions for key stakeholders and awareness campaigns for communities were organized. Results There were RDT-positive dengue cases reported from urban and semi-urban areas where entomological surveys also confirmed a high density of Aedes aegypti mosquitoes. Although there was an increase in dengue cases in January 2014, the number of cases remained below the epidemic threshold throughout the remaining months of 2014. Discussion There was no large outbreak of dengue after Haiyan, possibly due to the targeted, multifaceted and rapid response for dengue after Haiyan. However, surveillance differed after Typhoon Haiyan, making comparisons with previous years difficult. Multiple players contributed to the response that was also facilitated by close communication and coordination within the Health Cluster. PMID:26767138

  17. The prevention and control of dengue after Typhoon Haiyan.

    PubMed

    Aumentado, Charito; Cerro, Boyd Roderick; Olobia, Leonido; Suy, Lyndon Lee; Reyes, Aldrin; Kusumawathie, Pahalagedera H D; Sagrado, Maria; Hall, Julie Lyn; Abeyasinghe, Rabindra; Foxwell, Alice Ruth; Vestergaard, Lasse S

    2015-01-01

    Many of the areas in the Philippines affected by Typhoon Haiyan are endemic for dengue; therefore, dengue prevention was a priority in the initial post-disaster risk assessment. We describe the dengue prevention and response strategies applied after Haiyan. The dengue response was implemented by a wide range of national and international stakeholders. Priorities included the rapid re-establishment of an effective surveillance system to quickly identify new dengue cases, monitor trends and determine the geographical distribution of cases. Dengue rapid diagnostic tests (RDTs) were distributed to sentinel health facilities, and comprehensive vector control activities and entomological surveys were implemented. Several training sessions for key stakeholders and awareness campaigns for communities were organized. There were RDT-positive dengue cases reported from urban and semi-urban areas where entomological surveys also confirmed a high density of Aedes aegypti mosquitoes. Although there was an increase in dengue cases in January 2014, the number of cases remained below the epidemic threshold throughout the remaining months of 2014. There was no large outbreak of dengue after Haiyan, possibly due to the targeted, multifaceted and rapid response for dengue after Haiyan. However, surveillance differed after Typhoon Haiyan, making comparisons with previous years difficult. Multiple players contributed to the response that was also facilitated by close communication and coordination within the Health Cluster.

  18. Bromeliad-inhabiting mosquitoes in an urban botanical garden of dengue endemic Rio de Janeiro--are bromeliads productive habitats for the invasive vectors Aedes aegypti and Aedes albopictus?

    PubMed

    Mocellin, Márcio Goulart; Simões, Taynãna César; Nascimento, Teresa Fernandes Silva do; Teixeira, Maria Lucia França; Lounibos, Leon Philip; Oliveira, Ricardo Lourenço de

    2009-12-01

    Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus(0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats.

  19. Larvicidal Potential of the Halogenated Sesquiterpene (+)-Obtusol, Isolated from the Alga Laurencia dendroidea J. Agardh (Ceramiales: Rhodomelaceae), against the Dengue Vector Mosquito Aedes aegypti (Linnaeus) (Diptera: Culicidae)

    PubMed Central

    Salvador-Neto, Orlando; Gomes, Simone Azevedo; Soares, Angélica Ribeiro; Machado, Fernanda Lacerda da Silva; Samuels, Richard Ian; Nunes da Fonseca, Rodrigo; Souza-Menezes, Jackson; Moraes, Jorge Luiz da Cunha; Campos, Eldo; Mury, Flávia Borges; Silva, José Roberto

    2016-01-01

    Dengue is considered a serious public health problem in many tropical regions of the world including Brazil. At the moment, there is no viable alternative to reduce dengue infections other than controlling the insect vector, Aedes aegypti Linnaeus. In the continuing search for new sources of chemicals targeted at vector control, natural products are a promising alternative to synthetic pesticides. In our work, we investigated the toxicity of a bioactive compound extracted from the red alga Laurencia dendroidea J. Agardh. The initial results demonstrated that crude extracts, at a concentration of 5 ppm, caused pronounced mortality of second instar A. aegypti larvae. Two molecules, identified as (−)-elatol and (+)-obtusol were subsequently isolated from crude extract and further evaluated. Assays with (−)-elatol showed moderate larvicidal activity, whereas (+)-obtusol presented higher toxic activity than (−)-elatol, with a LC50 value of 3.5 ppm. Histological analysis of the larvae exposed to (+)-obtusol revealed damage to the intestinal epithelium. Moreover, (+)-obtusol-treated larvae incubated with 2 µM CM-H2DCFDA showed the presence of reactive oxygen species, leading us to suggest that epithelial damage might be related to redox imbalance. These results demonstrate the potential of (+)-obtusol as a larvicide for use against A. aegypti and the possible mode of action of this compound. PMID:26821032

  20. [Dengue vaccines. A reality for Argentina?].

    PubMed

    Orellano, Pablo W; Salomón, Oscar D

    2016-01-01

    Dengue outbreaks have occurred yearly in Argentina since 1998. A number of candidate vaccines have been tested in endemic countries. The most advanced one was licensed in three countries of Latin America for children over 9 years of age. In the present article the benefits and drawbacks of these vaccines as well as the challenges for the implementation of a vaccination strategy in Argentina are discussed. Furthermore, a risk stratification strategy with new criteria and a multidisciplinary vision is suggested as a possible path for the assessment of the pertinence of a vaccination program in areas showing the highest risk of dengue transmission and/or for people at the greatest risk of developing severe dengue. It is also suggested that the definition regarding the status of endemicity should take into account the local realities. Finally, this paper proposes a broad discussion on the evidences, the expected impact and instrumental aspects that would be involved in the incorporation of a dengue vaccine, marketed or in development, into the national immunization program, and especially which subpopulation should be targeted for the immunization strategy to be cost-effective.

  1. Human Immune Response to Dengue Infections

    DTIC Science & Technology

    1991-06-30

    complex 32 x 4G2 (Table 35, Exp. 4). A bispecific antibody which is specific for Fc RI and Toxoplasma gondii (32 x anti-TG) did not enhance infection...culture fluids of cells infected with dengue virus alone (Table 36, Exp. 2). A bispecific antibody linking Fc’RII to Toxoplasma gondii (IV.3 x anti-Tg

  2. Dengue vaccine: come let's fight the menace.

    PubMed

    Chawla, Sumit; Sahoo, Soumya Swaroop; Singh, Inderjeet; Verma, Madhur; Gupta, Vikas; Kumari, Sneh

    2015-01-01

    Although dengue has a global distribution, the World Health Organization (WHO) South-East Asia region together with Western Pacific region bears nearly 75% of the current global disease burden. Globally, the societal burden has been estimated to be approximately 528 to 1300 disability-adjusted life years (DALY) per million to populations in endemic regions Dengue is believed to infect 50 to 100 million people worldwide a year with half a million life-threatening infections requiring hospitalization, resulting in approximately 12,500 to 25,000 deaths. Despite being known for decades and nearly half the world's population is at risk for infection with as many as 100 million cases occurring annually, the pitiable state is that we still have no antiviral drugs to treat it and no vaccines to prevent it. In recent years, however, the development of dengue vaccines has accelerated dramatically in tandem with the burgeoning dengue problem with a rejuvenated vigour. However, recent progress in molecular-based vaccine strategies, as well as a renewed commitment by the World Health Organization (WHO) to co-ordinate global efforts on vaccine development, finally provides hope that control of this serious disease may be at hand. Today, several vaccines are in various stages of advanced development, with clinical trials currently underway on 5 candidate vaccines. Trials in the most advanced stages are showing encouraging preliminary data, and the leading candidate could be licensed as early as 2015.

  3. Multiobjective Genetic Algorithm applied to dengue control.

    PubMed

    Florentino, Helenice O; Cantane, Daniela R; Santos, Fernando L P; Bannwart, Bettina F

    2014-12-01

    Dengue fever is an infectious disease caused by a virus of the Flaviridae family and transmitted to the person by a mosquito of the genus Aedes aegypti. This disease has been a global public health problem because a single mosquito can infect up to 300 people and between 50 and 100 million people are infected annually on all continents. Thus, dengue fever is currently a subject of research, whether in the search for vaccines and treatments for the disease or efficient and economical forms of mosquito control. The current study aims to study techniques of multiobjective optimization to assist in solving problems involving the control of the mosquito that transmits dengue fever. The population dynamics of the mosquito is studied in order to understand the epidemic phenomenon and suggest strategies of multiobjective programming for mosquito control. A Multiobjective Genetic Algorithm (MGA_DENGUE) is proposed to solve the optimization model treated here and we discuss the computational results obtained from the application of this technique. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Dengue platelets meet Sir Arthur Conan Doyle.

    PubMed

    Bray, Paul F

    2013-11-14

    In this issue of Blood, Hottz et al provide compelling evidence that dengue virus (DV) induces (1) platelet synthesis of interleukin-1b (IL-1b); (2) platelet-derived IL-1b–containing microvesicles (MVs) that increase vascular permeability; and (3) DV-triggered inflammasome activation in platelets.

  5. Economic Value of Dengue Vaccine in Thailand

    PubMed Central

    Lee, Bruce Y.; Connor, Diana L.; Kitchen, Sarah B.; Bacon, Kristina M.; Shah, Mirat; Brown, Shawn T.; Bailey, Rachel R.; Laosiritaworn, Yongjua; Burke, Donald S.; Cummings, Derek A. T.

    2011-01-01

    With several candidate dengue vaccines under development, this is an important time to help stakeholders (e.g., policy makers, scientists, clinicians, and manufacturers) better understand the potential economic value (cost-effectiveness) of a dengue vaccine, especially while vaccine characteristics and strategies might be readily altered. We developed a decision analytic Markov simulation model to evaluate the potential health and economic value of administering a dengue vaccine to an individual (≤ 1 year of age) in Thailand from the societal perspective. Sensitivity analyses evaluated the effects of ranging various vaccine (e.g., cost, efficacy, side effect), epidemiological (dengue risk), and disease (treatment-seeking behavior) characteristics. A ≥ 50% efficacious vaccine was highly cost-effective [< 1× per capita gross domestic product (GDP) ($4,289)] up to a total vaccination cost of $60 and cost-effective [< 3× per capita GDP ($12,868)] up to a total vaccination cost of $200. When the total vaccine series was $1.50, many scenarios were cost saving. PMID:21540387

  6. Dengue Virus Genome Uncoating Requires Ubiquitination

    PubMed Central

    Byk, Laura A.; Iglesias, Néstor G.; De Maio, Federico A.; Gebhard, Leopoldo G.; Rossi, Mario

    2016-01-01

    ABSTRACT The process of genome release or uncoating after viral entry is one of the least-studied steps in the flavivirus life cycle. Flaviviruses are mainly arthropod-borne viruses, including emerging and reemerging pathogens such as dengue, Zika, and West Nile viruses. Currently, dengue virus is one of the most significant human viral pathogens transmitted by mosquitoes and is responsible for about 390 million infections every year around the world. Here, we examined for the first time molecular aspects of dengue virus genome uncoating. We followed the fate of the capsid protein and RNA genome early during infection and found that capsid is degraded after viral internalization by the host ubiquitin-proteasome system. However, proteasome activity and capsid degradation were not necessary to free the genome for initial viral translation. Unexpectedly, genome uncoating was blocked by inhibiting ubiquitination. Using different assays to bypass entry and evaluate the first rounds of viral translation, a narrow window of time during infection that requires ubiquitination but not proteasome activity was identified. In this regard, ubiquitin E1-activating enzyme inhibition was sufficient to stabilize the incoming viral genome in the cytoplasm of infected cells, causing its retention in either endosomes or nucleocapsids. Our data support a model in which dengue virus genome uncoating requires a nondegradative ubiquitination step, providing new insights into this crucial but understudied viral process. PMID:27353759

  7. Proteinuria during dengue fever in children.

    PubMed

    Andries, Anne-Claire; Duong, Veasna; Cappelle, Julien; Ong, Sivuth; Kerleguer, Alexandra; Ly, Sowath; Tarantola, Arnaud; Horwood, Paul F; Sakuntabhai, Anavaj; Dussart, Philippe; Buchy, Philippe

    2017-02-01

    This study aimed to investigate proteinuria occurring during dengue disease in children and assess if measurement of this parameter can help physicians in the clinical management of patients. Proteinuria was assessed by dipstick and quantified by urine protein:creatinine ratio (UPCR) in samples from patients hospitalized with a confirmed dengue infection and in healthy controls. The dipstick tested positive in 42.9% of the patients presenting at hospital with dengue versus 20.0% in healthy controls. UPCR increased during the critical phase of the disease; peaking one week after fever onset then decreasing as the patients recovered. Patients with warnings signs or severe dengue were more likely to present with proteinuria detected by UPCR at the time of hospital admission compared to patients without warning signs. The sensitivity of this marker, however, was limited as only 16.1% of the patients with warning signs had proteinuria. Urine dipstick and UPCR do not seem to be very valuable for the triage of the patients at the time of the initial consultation but the observation of a decrease of the UPCR during the course of the illness appears to indicate an evolution towards recovery. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Dengue Virus Serotype 4, Northeastern Peru, 2008

    PubMed Central

    Forshey, Brett M.; Morrison, Amy C.; Cruz, Cristhopher; Rocha, Claudio; Vilcarromero, Stalin; Guevara, Carolina; Camacho, Daria E.; Alava, Araceli; Madrid, César; Beingolea, Luis; Suarez, Víctor; Comach, Guillermo

    2009-01-01

    In 2008, dengue virus serotype 4 (DENV-4) emerged in northeastern Peru, causing a large outbreak and displacing DENV-3, which had predominated for the previous 6 years. Phylogenetic analysis of 2008 and 2009 isolates support their inclusion into DENV-4 genotype II, forming a lineage distinct from strains that had previously circulated in the region. PMID:19891873

  9. Dengue virus serotype 4, northeastern Peru, 2008.

    PubMed

    Forshey, Brett M; Morrison, Amy C; Cruz, Cristhopher; Rocha, Claudio; Vilcarromero, Stalin; Guevara, Carolina; Camacho, Daria E; Alava, Araceli; Madrid, César; Beingolea, Luis; Suarez, Victor; Comach, Guillermo; Kochel, Tadeusz J

    2009-11-01

    In 2008, dengue virus serotype 4 (DENV-4) emerged in northeastern Peru, causing a large outbreak and displacing DENV-3, which had predominated for the previous 6 years. Phylogenetic analysis of 2008 and 2009 isolates support their inclusion into DENV-4 genotype II, forming a lineage distinct from strains that had previously circulated in the region.

  10. Influenza Illness among Case-Patients Hospitalized for Suspected Dengue, El Salvador, 2012.

    PubMed

    Chacon, Rafael; Clara, Alexey Wilfrido; Jara, Jorge; Armero, Julio; Lozano, Celina; El Omeiri, Nathalie; Widdowson, Marc-Alain; Azziz-Baumgartner, Eduardo

    2015-01-01

    We estimate the proportion of patients hospitalized for suspected dengue that tested positive for influenza virus in El Salvador during the 2012 influenza season. We tested specimens from 321 hospitalized patients: 198 patients with SARI and 123 patients with suspected dengue. Among 121 hospitalized suspected dengue (two co-infected excluded) patients, 28% tested positive for dengue and 19% positive for influenza; among 35 with suspected dengue and respiratory symptoms, 14% were positive for dengue and 39% positive for influenza. One percent presented co-infection between influenza and dengue. Clinicians should consider the diagnosis of influenza among patients with suspected dengue during the influenza season.

  11. Influenza Illness among Case-Patients Hospitalized for Suspected Dengue, El Salvador, 2012

    PubMed Central

    Chacon, Rafael; Jara, Jorge; Armero, Julio; Lozano, Celina

    2015-01-01

    We estimate the proportion of patients hospitalized for suspected dengue that tested positive for influenza virus in El Salvador during the 2012 influenza season. We tested specimens from 321 hospitalized patients: 198 patients with SARI and 123 patients with suspected dengue. Among 121 hospitalized suspected dengue (two co-infected excluded) patients, 28% tested positive for dengue and 19% positive for influenza; among 35 with suspected dengue and respiratory symptoms, 14% were positive for dengue and 39% positive for influenza. One percent presented co-infection between influenza and dengue. Clinicians should consider the diagnosis of influenza among patients with suspected dengue during the influenza season. PMID:26485296

  12. Behavior of Settling Marine Larvae in Flow

    NASA Astrophysics Data System (ADS)

    Hernandez, J.; Koehl, M. A.

    2012-12-01

    Many bottom-dwelling marine animals produce microscopic larvae that are dispersed by ambient water currents. These larvae can only recruit to habitats on which they have landed if they can resist being washed away by ambient water flow. We found that larvae on marine surfaces do not experience steady water flow, but rather are exposed to brief pulses of water movement as turbulent eddies sweep across them. We made video recordings of larvae of the tube worm, Hydroides elegans, (important members of the community of organisms growing on docks and ships) on surfaces subjected to measured realistic flow pulses to study factors that might affect their dislodgement from surfaces in nature. We found that the response of a larva of H. elegans to a realistic pulse of water flow depended on its behavior at the time of the pulse and on its recent history of exposure to flow pulses, and that stationary larvae were less likely than locomoting larvae to be blown away when hit by the first pulse of water flow.; ;

  13. Hyperparasitism of mosquitoes by water mite larvae.

    PubMed

    Werblow, Antje; Martin, Peter; Dörge, Dorian D; Koch, Lisa K; Mehlhorn, Heinz; Melaun, Christian; Klimpel, Sven

    2015-07-01

    Hyperparasitism of ectoparasitic water mite larvae on mosquitoes is still a neglected relationship and was investigated only in a few studies. We analysed 2313 female mosquitoes from six different sampling localities with regard to their degree of parasitism with water mite larvae. In total, we found 38 mosquito individuals parasitized by 93 water mite larvae, ranging from 1 to 12 larvae per mosquito. Water mite larvae detected are members of the two species Parathyas cf. barbigera (n = 92) and Arrenurus cf. globator (n = 1). Out of the analysed mosquitoes, individuals out of the species Aedes vexans, Anopheles claviger, Ochlerotatus communis, the Ochlerotatus cantans/annulipes group, Ochlerotatus cataphylla and Ochlerotatus sticticus were tested to be parasitized by water mite larvae. The highest prevalence was found within the species Oc. cataphylla (28.6 %) and Oc. cantans/annulipes (21.7 %). No water mite larvae were found, e.g. on individuals of Aedes cinereus, Coquillettidia richiardii, the Culex pipiens/torrentium group, Ochlerotatus caspius, Ochlerotatus dorsalis or Ochlerotatus punctor. All of the attachment sites were located between the neck and abdomen with the ventral thorax site being the most frequent one.

  14. Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality.

    PubMed

    Alkhaibari, Abeer M; Carolino, Aline T; Yavasoglu, Sare I; Maffeis, Thierry; Mattoso, Thalles C; Bull, James C; Samuels, Richard I; Butt, Tariq M

    2016-07-01

    Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world's population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti larvae

  15. Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality

    PubMed Central

    Alkhaibari, Abeer M.; Carolino, Aline T.; Yavasoglu, Sare I.; Maffeis, Thierry; Mattoso, Thalles C.; Bull, James C.; Samuels, Richard I.; Butt, Tariq M.

    2016-01-01

    Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world’s population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti

  16. Is dengue severity related to nutritional status?

    PubMed

    Kalayanarooj, Siripen; Nimmannitya, Suchitra

    2005-03-01

    A retrospective review of dengue patients admitted to Queen Sirikit National Institute of Child Health (previously known as Children's Hospital) from 1995 to 1999 revealed 4,532 confirmed cases of dengue infection; 80.9% were dengue hemorrhagic fever (DHF) and 19.1% were dengue fever cases (DF). Among the DHF patients; 30.6% had shock. The majority of them, 66.6%, had a normal nutritional status, while 9.3% were malnourished and 24.2% had obesity as classified by weight for age. Compared with control patients with other diagnoses (excluding HIV/AIDS patients), malnourished children had a lower risk of contracting dengue infection (odds ratio = 0.48, 95% Cl = 0.39-0.60, p = 0.000) while obese children had a greater risk of infection with dengue viruses (odds ratio = 1.96, 95% Cl = 1.55-2.5, p = 0.000). The clinical signs, symptoms and laboratory findings of dengue were almost the same among the 3 groups of malnourished, normal, and obese patients. The minor differences observed were that in obese children liver enlargement was found less often; maculopapular/convalescence rash and elevations of alanine aminotransferase were found more often. Malnourished patients had a higher risk of developing shock (37.8%) than normal (29.9%) and obese patients (30.2%) (p = 0.000). Obese patients had more unusual presentations: encephalopathy (1.3%) and associated infections (4.8%), than normal (0.5% and 2.7%) and malnourished patients (1.2% and 3.1%). Complications of fluid overload were found more in obese patients (6.5%) compared to normal (3.2%) and malnourished patients (2.1%) (p = 0.000). The case-fatality rates (CFR) in malnourished patients and obese patients were 0.5% and 0.4%, respectively, while in normal patients the CFR was 0.07%. Under and over nutrition DHF patients had either a greater risk of shock or unusual presentations and complications, which can lead to severe disease or complications and probably a higher CFR.

  17. Cutaneous Larva Migrans in Early Infancy

    PubMed Central

    Siddalingappa, Karjigi; Murthy, Sambasiviah Chidambara; Herakal, Kallappa; Kusuma, Marganahalli Ramachandra

    2015-01-01

    Cutaneous larva migrans or creeping eruptions is a cutaneous dermatosis caused by hookworm larvae, Ancylostoma braziliense. A 2-month-old female child presented with a progressive rash over the left buttock of 4 days duration. Cutaneous examination showed an urticarial papule progressing to erythematous, tortuous, thread-like tract extending a few centimeters from papule over the left gluteal region. A clinical diagnosis of cutaneous larva migrans was considered. Treatment with albendazole led to complete resolution, confirming the diagnosis. This is to the best of our knowledge, the youngest age at which this condition is being reported. PMID:26538729

  18. Visualizing dengue virus through Alexa Fluor labeling.

    PubMed

    Zhang, Summer; Tan, Hwee Cheng; Ooi, Eng Eong

    2011-07-09

    The early events in the interaction between virus and cell can have profound influence on the outcome of infection. Determining the factors that influence this interaction could lead to improved understanding of disease pathogenesis and thus influence vaccine or therapeutic design. Hence, the development of methods to probe this interaction would be useful. Recent advancements in fluorophores development and imaging technology can be exploited to improve our current knowledge on dengue pathogenesis and thus pave the way to reduce the millions of dengue infections occurring annually. The enveloped dengue virus has an external scaffold consisting of 90 envelope glycoprotein (E) dimers protecting the nucleocapsid shell, which contains a single positive strand RNA genome. The identical protein subunits on the virus surface can thus be labeled with an amine reactive dye and visualized through immunofluorescent microscopy. Here, we present a simple method of labeling of dengue virus with Alexa Fluor succinimidyl ester dye dissolved directly in a sodium bicarbonate buffer that yielded highly viable virus after labeling. There is no standardized procedure for the labeling of live virus and existing manufacturer's protocol for protein labeling usually requires the reconstitution of dye in dimethyl sulfoxide. The presence of dimethyl sulfoxide, even in minute quantities, can block productive infection of virus and also induce cell cytotoxicity. The exclusion of the use of dimethyl sulfoxide in this protocol thus reduced this possibility. Alexa Fluor dyes have superior photostability and are less pH-sensitive than the common dyes, such as fluorescein and rhodamine, making them ideal for studies on cellular uptake and endosomal transport of the virus. The conjugation of Alexa Fluor dye did not affect the recognition of labeled dengue virus by virus-specific antibody and its putative receptors in host cells. This method could have useful applications in virological studies.

  19. The successful induction of T-cell and antibody responses by a recombinant measles virus-vectored tetravalent dengue vaccine provides partial protection against dengue-2 infection

    PubMed Central

    Hu, Hui-Mei; Chen, Hsin-Wei; Hsiao, Yu-Ju; Wu, Szu-Hsien; Chung, Han-Hsuan; Hsieh, Chun-Hsiang; Chong, Pele; Leng, Chih-Hsiang; Pan, Chien-Hsiung

    2016-01-01

    ABSTRACT Dengue has a major impact on global public health, and the use of dengue vaccine is very limited. In this study, we evaluated the immunogenicity and protective efficacy of a dengue vaccine made from a recombinant measles virus (MV) that expresses envelope protein domain III (ED3) of dengue-1 to 4. Following immunization with the MV-vectored dengue vaccine, mice developed specific interferon-gamma and antibody responses against dengue virus and MV. Neutralizing antibodies against MV and dengue viruses were also induced, and protective levels of FRNT50 ≥ 10 to 4 serotypes of dengue viruses were detected in the MV-vectored dengue vaccine-immunized mice. In addition, specific interferon-gamma and antibody responses to dengue viruses were still induced by the MV-vectored dengue vaccine in mice that were pre-infected with MV. This finding suggests that the pre-existing immunity to MV did not block the initiation of immune responses. By contrast, mice that were pre-infected with dengue-3 exhibited no effect in terms of their antibody responses to MV and dengue viruses, but a dominant dengue-3-specific T-cell response was observed. After injection with dengue-2, a detectable but significantly lower viremia and a higher titer of anti-dengue-2 neutralizing antibodies were observed in MV-vectored dengue vaccine-immunized mice versus the vector control, suggesting that an anamnestic antibody response that provided partial protection against dengue-2 was elicited. Our results with regard to T-cell responses and the effect of pre-immunity to MV or dengue viruses provide clues for the future applications of an MV-vectored dengue vaccine. PMID:26901482

  20. Molecular and epidemiologic analysis of dengue virus isolates from Somalia.

    PubMed

    Kanesa-thasan, N; Chang, G J; Smoak, B L; Magill, A; Burrous, M J; Hoke, C H

    1998-01-01

    Nucleotide sequence analysis was performed on 14 dengue virus isolates (13 dengue-2 viruses and 1 dengue-3 virus) recovered from febrile soldiers in Somalia in 1993. The dengue-2 viruses were most closely related to dengue-2 virus recovered in Somalia in 1984. However, differences in nucleotide sequence (0.35% to 1.35%) were evident among the 1993 isolates. These differences were closely associated with the geographic location of the infection as well as with different times of infection at the same location. Genetic difference between strains was not associated with differences in clinical features. Molecular analysis of dengue viruses is a useful adjunct to epidemiologic investigation of their distribution over distance and time.

  1. Advances in using Internet searches to track dengue

    PubMed Central

    Yang, Shihao; Kou, Samuel C.; Brownstein, John S.; Brooke, Nicholas

    2017-01-01

    Dengue is a mosquito-borne disease that threatens over half of the world’s population. Despite being endemic to more than 100 countries, government-led efforts and tools for timely identification and tracking of new infections are still lacking in many affected areas. Multiple methodologies that leverage the use of Internet-based data sources have been proposed as a way to complement dengue surveillance efforts. Among these, dengue-related Google search trends have been shown to correlate with dengue activity. We extend a methodological framework, initially proposed and validated for flu surveillance, to produce near real-time estimates of dengue cases in five countries/states: Mexico, Brazil, Thailand, Singapore and Taiwan. Our result shows that our modeling framework can be used to improve the tracking of dengue activity in multiple locations around the world. PMID:28727821

  2. Advances in using Internet searches to track dengue.

    PubMed

    Yang, Shihao; Kou, Samuel C; Lu, Fred; Brownstein, John S; Brooke, Nicholas; Santillana, Mauricio

    2017-07-01

    Dengue is a mosquito-borne disease that threatens over half of the world's population. Despite being endemic to more than 100 countries, government-led efforts and tools for timely identification and tracking of new infections are still lacking in many affected areas. Multiple methodologies that leverage the use of Internet-based data sources have been proposed as a way to complement dengue surveillance efforts. Among these, dengue-related Google search trends have been shown to correlate with dengue activity. We extend a methodological framework, initially proposed and validated for flu surveillance, to produce near real-time estimates of dengue cases in five countries/states: Mexico, Brazil, Thailand, Singapore and Taiwan. Our result shows that our modeling framework can be used to improve the tracking of dengue activity in multiple locations around the world.

  3. [Evaluation of the Brazilian National Dengue Control Plan].

    PubMed

    Pessanha, José Eduardo Marques; Caiaffa, Waleska Teixeira; César, Cibele Comini; Proietti, Fernando Augusto

    2009-07-01

    This study aimed to describe and evaluate dengue patterns after the implementation of the National Dengue Control Plan (PNCD). Incidence rates were analyzed and correlated with previous rates and climatic, demographic, and socioeconomic variables for the Brazilian municipalities that were targeted for priority dengue control. We conducted descriptive studies of epidemiological indicators after the implementation of the national plan and a statistical analysis considering the incidence rates from the previous period and climatic, demographic, and socioeconomic variables, using multiple linear regression. We found a significant association between dengue incidence during the period following implementation of the PNCD (2003-2006) as compared to pre-implementation (2001-2002), after adjusting for geographic and climatic indicators. Our findings suggest that the plan's objectives were not fully achieved. In conclusion, the persistent occurrence of dengue epidemics requires changes and reevaluation of current strategies, along with improvements in the dengue surveillance system.

  4. Economic Impact of Dengue Illness in the Americas

    PubMed Central

    Shepard, Donald S.; Coudeville, Laurent; Halasa, Yara A.; Zambrano, Betzana; Dayan, Gustavo H.

    2011-01-01

    The growing burden of dengue in endemic countries and outbreaks in previously unaffected countries stress the need to assess the economic impact of this disease. This paper synthesizes existing studies to calculate the economic burden of dengue illness in the Americas from a societal perspective. Major data sources include national case reporting data from 2000 to 2007, prospective cost of illness studies, and analyses quantifying underreporting in national routine surveillance systems. Dengue illness in the Americas was estimated to cost $2.1 billion per year on average (in 2010 US dollars), with a range of $1–4 billion in sensitivity analyses and substantial year to year variation. The results highlight the substantial economic burden from dengue in the Americas. The burden for dengue exceeds that from other viral illnesses, such as human papillomavirus (HPV) or rotavirus. Because this study does not include some components (e.g., vector control), it may still underestimate total economic consequences of dengue. PMID:21292885

  5. Cardiac tamponade presenting as early manifestation in dengue fever.

    PubMed

    Bendwal, Suresh; Malviya, Kavita; Jatav, O P; Malviya, Kapil

    2014-03-01

    Dengue fever (DF) is an outbreak prone viral disease transmitted by aedes mosquitoes. It is often associated with evidence of plasma leakage due to increased vascular permeability manifested by pleural effusion, ascites, hypoproteinaemia and pericardial effusion. Cases of small pericardial effusion have been reported in association with dengue fever, largely with dengue haemorrhagic fever (DHF) during epidemic outbreaks. Dengue may rarely present with cardiac tamponade as early manifestation and urgent pericardiocentesis is life saving. A 34 year old male presented with low grade fever, headache, myalgia and breathlessness. Echocardiography revealed large pericardial effusion with right ventricular diagnostic collapse requiring urgent drainage. Subsequently patient improved. Dengue serology (both IgM and IgG) was reported as markedly elevated supporting a diagnosis of classic dengue fever.

  6. Underrecognition of Dengue during 2013 Epidemic in Luanda, Angola.

    PubMed

    Sharp, Tyler M; Moreira, Rosa; Soares, Maria José; Miguel da Costa, Lúis; Mann, Jennifer; DeLorey, Mark; Hunsperger, Elizabeth; Muñoz-Jordán, Jorge L; Colón, Candimar; Margolis, Harold S; de Caravalho, Adelaide; Tomashek, Kay M

    2015-08-01

    During the 2013 dengue epidemic in Luanda, Angola, 811 dengue rapid diagnostic test-positive cases were reported to the Ministry of Health. To better understand the magnitude of the epidemic and identify risk factors for dengue virus (DENV) infection, we conducted cluster surveys around households of case-patients and randomly selected households 6 weeks after the peak of the epidemic. Of 173 case cluster participants, 16 (9%) exhibited evidence of recent DENV infection. Of 247 random cluster participants, 25 (10%) had evidence of recent DENV infection. Of 13 recently infected participants who had a recent febrile illness, 7 (54%) had sought medical care, and 1 (14%) was hospitalized with symptoms consistent with severe dengue; however, none received a diagnosis of dengue. Behavior associated with protection from DENV infection included recent use of mosquito repellent or a bed net. These findings suggest that the 2013 dengue epidemic was larger than indicated by passive surveillance data.

  7. Evaluation of Internet-Based Dengue Query Data: Google Dengue Trends

    PubMed Central

    Gluskin, Rebecca Tave; Johansson, Michael A.; Santillana, Mauricio; Brownstein, John S.

    2014-01-01

    Dengue is a common and growing problem worldwide, with an estimated 70–140 million cases per year. Traditional, healthcare-based, government-implemented dengue surveillance is resource intensive and slow. As global Internet use has increased, novel, Internet-based disease monitoring tools have emerged. Google Dengue Trends (GDT) uses near real-time search query data to create an index of dengue incidence that is a linear proxy for traditional surveillance. Studies have shown that GDT correlates highly with dengue incidence in multiple countries on a large spatial scale. This study addresses the heterogeneity of GDT at smaller spatial scales, assessing its accuracy at the state-level in Mexico and identifying factors that are associated with its accuracy. We used Pearson correlation to estimate the association between GDT and traditional dengue surveillance data for Mexico at the national level and for 17 Mexican states. Nationally, GDT captured approximately 83% of the variability in reported cases over the 9 study years. The correlation between GDT and reported cases varied from state to state, capturing anywhere from 1% of the variability in Baja California to 88% in Chiapas, with higher accuracy in states with higher dengue average annual incidence. A model including annual average maximum temperature, precipitation, and their interaction accounted for 81% of the variability in GDT accuracy between states. This climate model was the best indicator of GDT accuracy, suggesting that GDT works best in areas with intense transmission, particularly where local climate is well suited for transmission. Internet accessibility (average ∼36%) did not appear to affect GDT accuracy. While GDT seems to be a less robust indicator of local transmission in areas of low incidence and unfavorable climate, it may indicate cases among travelers in those areas. Identifying the strengths and limitations of novel surveillance is critical for these types of data to be used to make

  8. Clinical Score to Differentiate Scrub Typhus and Dengue: A Tool to Differentiate Scrub Typhus and Dengue

    PubMed Central

    Mitra, Shubhanker; Gautam, Ira; Jambugulam, Mohan; Abhilash, Kundavaram Paul Prabhakar; Jayaseeelan, Vishalakshi

    2017-01-01

    Background: Dengue and scrub typhus share similar clinical and epidemiological features, and are difficult to differentiate at initial presentation. Many places are endemic to both these infections where they comprise the majority of acute undifferentiated febrile illnesses. Materials and Methods: We aimed to develop a score that can differentiate scrub typhus from dengue. In this cross-sectional study, 188 cases of scrub typhus and 201 cases of dengue infection who presented to the emergency department or medicine outpatient clinic from September 2012 to April 2013 were included. Univariate followed by multivariate logistic regression analysis was performed to identify clinical features and laboratory results that were significantly different between the two groups. Each variable was assigned scores based on the strength of association and receiver operating characteristics area under the curve (ROC-AUC) was generated and compared. Six scoring models were explored to ascertain the model with the best fit. Results: Model 2 was developed using the following six variables: oxygen saturation (>90%, ≤90%), total white blood cell count (<4000, 4001–7000 and >7000 cells/cumm), hemoglobin (≤14 and >14 g/dL), total bilirubin (<2 and ≥2 mg/dL), serum glutamic oxaloacetic transaminase (>200 and ≥200 IU/dL), and altered sensorium (present or absent). Each variable was assigned scores based on its strength of association. The AUC-ROC curve (95% confidence interval) for model 2 was 0.84 (0.79–0.89). At the cut off score of 13, the sensitivity and specificity were 85% and 77% respectively, with a higher score favoring dengue. Conclusion: In areas of high burden of ST and dengue, model 2 (the “clinical score to differentiate scrub typhus and dengue fever”) is a simple and rapid clinical scoring system that may be used to differentiate scrub typhus and dengue at initial presentation. PMID:28250620

  9. Evaluation of Internet-based dengue query data: Google Dengue Trends.

    PubMed

    Gluskin, Rebecca Tave; Johansson, Michael A; Santillana, Mauricio; Brownstein, John S

    2014-02-01

    Dengue is a common and growing problem worldwide, with an estimated 70-140 million cases per year. Traditional, healthcare-based, government-implemented dengue surveillance is resource intensive and slow. As global Internet use has increased, novel, Internet-based disease monitoring tools have emerged. Google Dengue Trends (GDT) uses near real-time search query data to create an index of dengue incidence that is a linear proxy for traditional surveillance. Studies have shown that GDT correlates highly with dengue incidence in multiple countries on a large spatial scale. This study addresses the heterogeneity of GDT at smaller spatial scales, assessing its accuracy at the state-level in Mexico and identifying factors that are associated with its accuracy. We used Pearson correlation to estimate the association between GDT and traditional dengue surveillance data for Mexico at the national level and for 17 Mexican states. Nationally, GDT captured approximately 83% of the variability in reported cases over the 9 study years. The correlation between GDT and reported cases varied from state to state, capturing anywhere from 1% of the variability in Baja California to 88% in Chiapas, with higher accuracy in states with higher dengue average annual incidence. A model including annual average maximum temperature, precipitation, and their interaction accounted for 81% of the variability in GDT accuracy between states. This climate model was the best indicator of GDT accuracy, suggesting that GDT works best in areas with intense transmission, particularly where local climate is well suited for transmission. Internet accessibility (average ∼ 36%) did not appear to affect GDT accuracy. While GDT seems to be a less robust indicator of local transmission in areas of low incidence and unfavorable climate, it may indicate cases among travelers in those areas. Identifying the strengths and limitations of novel surveillance is critical for these types of data to be used to make

  10. [Dengue fever in Portuguese speaking countries: which epidemiological links may we set?].

    PubMed

    Silvano, José; Abreu, Cândida

    2014-01-01

    Introdução: A ocorrência recente de um conjunto de surtos de dengue em países da lusofonia previamente livres de doença, despertou- nos curiosidade quanto aos fatores concorrentes para o fenómeno e a necessidade de aprofundar conhecimentos quanto à patologia. Revemos a situação relativa à dengue nos países da lusofonia, relacionando os diferentes surtos e procurando contribuir para um melhor conhecimento do fenómeno. Material e Métodos: Revisão da literatura relativa ao tema e informação relevante obtida de comunicações orais. Resultados: Os surtos ocorridos entre os anos de 2009 e 2013 em Cabo Verde, Madeira e Angola (para lá da doença endémica no Brasil) partilham o mesmo vetor Aedes aegypti, mas são devidos a serotipos víricos com diferentes proveniências, como constatado em estudos genotípicos. A forte sub-notificação da doença em África e as dificuldades no diagnóstico e terapêutica são obstáculos ao real conhecimento da situação. Discussão: A hipótese de ligação entre alguns dos surtos não está completamente afastada. Pela elevada mobilidade de pessoas entre estas zonas e pelas alterações climáticas em curso, o território de Portugal expõe-se ao risco de introdução de dengue. A luta principal, a despeito de ferramentas emergentes ainda utópicas, é sem dúvida o controlo vetorial. Conclusão: Não foi possível provar qualquer ligação entre os diferentes surtos, mas é necessária preparação local dos profissionais de saúde, bem como o estabelecimento de estratégias de saúde pública e manutenção de redes de vigilância. Mais estudos epidemiológicos e entomológicos são necessários para caracterizar a verdadeira incidência de doença nos países lusófonos.

  11. TIME management by medicinal larvae.

    PubMed

    Pritchard, David I; Čeřovský, Václav; Nigam, Yamni; Pickles, Samantha F; Cazander, Gwendolyn; Nibbering, Peter H; Bültemann, Anke; Jung, Wilhelm

    2016-08-01

    Wound bed preparation (WBP) is an integral part of the care programme for chronic wounds. The acronym TIME is used in the context of WBP and describes four barriers to healing in chronic wounds; namely, dead Tissue, Infection and inflammation, Moisture imbalance and a non-migrating Edge. Larval debridement therapy (LDT) stems from observations that larvae of the blowfly Lucilia sericata clean wounds of debris. Subsequent clinical studies have proven debriding efficacy, which is likely to occur as a result of enzymatically active alimentary products released by the insect. The antimicrobial, anti-inflammatory and wound healing activities of LDT have also been investigated, predominantly in a pre-clinical context. This review summarises the findings of investigations into the molecular mechanisms of LDT and places these in context with the clinical concept of WBP and TIME. It is clear from these findings that biotherapy with L. sericata conforms with TIME, through the enzymatic removal of dead tissue and its associated biofilm, coupled with the secretion of defined antimicrobial peptides. This biotherapeutic impact on the wound serves to reduce inflammation, with an associated capacity for an indirect effect on moisture imbalance. Furthermore, larval serine proteinases have the capacity to alter fibroblast behaviour in a manner conducive to the formation of granulation tissue.

  12. Lethal infection thresholds of Paenibacillus larvae for honeybee drone and worker larvae (Apis mellifera).

    PubMed

    Behrens, Dieter; Forsgren, Eva; Fries, Ingemar; Moritz, Robin F A

    2010-10-01

    We compared the mortality of honeybee (Apis mellifera) drone and worker larvae from a single queen under controlled in vitro conditions following infection with Paenibacillus larvae, a bacterium causing the brood disease American Foulbrood (AFB). We also determined absolute P. larvae cell numbers and lethal titres in deceased individuals of both sexes up to 8 days post infection using quantitative real-time PCR (qPCR). Our results show that in drones the onset of infection induced mortality is delayed by 1 day, the cumulative mortality is reduced by 10% and P. larvae cell numbers are higher than in worker larvae. Since differences in bacterial cell titres between sexes can be explained by differences in body size, larval size appears to be a key parameter for a lethal threshold in AFB tolerance. Both means and variances for lethal thresholds are similar for drone and worker larvae suggesting that drone resistance phenotypes resemble those of related workers.

  13. Meteorologically Driven Simulations of Dengue Epidemics in San Juan, PR

    PubMed Central

    Morin, Cory W.; Monaghan, Andrew J.; Hayden, Mary H.; Barrera, Roberto; Ernst, Kacey

    2015-01-01

    Meteorological factors influence dengue virus ecology by modulating vector mosquito population dynamics, viral replication, and transmission. Dynamic modeling techniques can be used to examine how interactions among meteorological variables, vectors and the dengue virus influence transmission. We developed a dengue fever simulation model by coupling a dynamic simulation model for Aedes aegypti, the primary mosquito vector for dengue, with a basic epidemiological Susceptible-Exposed-Infectious-Recovered (SEIR) model. Employing a Monte Carlo approach, we simulated dengue transmission during the period of 2010–2013 in San Juan, PR, where dengue fever is endemic. The results of 9600 simulations using varied model parameters were evaluated by statistical comparison (r2) with surveillance data of dengue cases reported to the Centers for Disease Control and Prevention. To identify the most influential parameters associated with dengue virus transmission for each period the top 1% of best-fit model simulations were retained and compared. Using the top simulations, dengue cases were simulated well for 2010 (r2 = 0.90, p = 0.03), 2011 (r2 = 0.83, p = 0.05), and 2012 (r2 = 0.94, p = 0.01); however, simulations were weaker for 2013 (r2 = 0.25, p = 0.25) and the entire four-year period (r2 = 0.44, p = 0.002). Analysis of parameter values from retained simulations revealed that rain dependent container habitats were more prevalent in best-fitting simulations during the wetter 2010 and 2011 years, while human managed (i.e. manually filled) container habitats were more prevalent in best-fitting simulations during the drier 2012 and 2013 years. The simulations further indicate that rainfall strongly modulates the timing of dengue (e.g., epidemics occurred earlier during rainy years) while temperature modulates the annual number of dengue fever cases. Our results suggest that meteorological factors have a time-variable influence on dengue transmission relative to other important

  14. Imported dengue virus serotype 1 from Madeira to Finland 2012.

    PubMed

    Huhtamo, E; Korhonen, Em; Vapalahti, O

    2013-02-21

    Imported dengue cases originating from the Madeiran outbreak are increasingly reported. In 2012 five Finnish travellers returning from Madeira were diagnosed with dengue fever. Viral sequence data was obtained from two patients. The partial C-preM sequences (399 and 396 bp respectively) were found similar to that of an autochthonous case from Madeira. The partial E-gene sequence (933 bp) which was identical among the two patients grouped phylogenetically with South American strains of dengue virus serotype 1.

  15. Knowledge, attitudes and practices regarding dengue infection in Westmoreland, Jamaica

    PubMed Central

    Shuaib, Faisal; Todd, Dana; Campbell-Stennett, Dianne; Ehiri, John; Jolly, Pauline E.

    2010-01-01

    Background Dengue virus infection causes significant morbidity and mortality in most tropical and sub-tropical countries of the world. Dengue fever is endemic in Jamaica and continues to be a public health concern. There is a paucity of information on knowledge, attitudes, and practices (KAP) of Jamaicans regarding dengue infection. Objective To describe dengue related knowledge, attitudes and practices (KAP) of residents of Westmoreland, Jamaica. Methods A cross-sectional questionnaire survey of 192 parents attending child health clinics in the Parish of Westmoreland was conducted. Results More than half of the parents (54%) had good knowledge about signs, symptoms, and modes of transmission of dengue. Approximately 47% considered dengue to be a serious but preventable disease to which they are vulnerable. Nevertheless, a majority (77%) did not use effective dengue preventive methods such as screening of homes and 51% did not use bed nets. Educational attainment (OR, 2.98; CI, 1.23–7.23) was positively associated with knowledge of dengue. There was no correlation between knowledge about dengue and preventive practices (p=0.34). Radio and TV were the predominant sources of information about dengue fever. Conclusion Our findings suggest that the good knowledge about dengue fever among residents of Westmoreland did not translate to adoption of preventive measures. Health program planners and practitioners need to identify and facilitate removal of barriers to behavior change related to control of dengue fever among the population. Future campaigns should focus on educating and encouraging individuals and families to adopt such simple, inexpensive preventive actions, such as, use of insecticide treated bed nets and screening of homes. PMID:21132094

  16. Fatal Dengue Myocarditis despite the Use of Extracorporeal Membrane Oxygenation

    PubMed Central

    2016-01-01

    Dengue is an important mosquitoes-borne viral disease which is endemic in tropics and subtropics region. Rapid spreading of disease to previously unaffected region was found in recent years. Atypical manifestations, such as myocarditis, were reported during large outbreak. There is a wide range of clinical manifestations of cardiac involvement in dengue, but rarely fatal. Here we reported a case of fulminant dengue myocarditis in fatal outcome despite cardiac mechanical support. PMID:28018687

  17. Dengue Type 3 Virus, Saint Martin, 2003–2004

    PubMed Central

    Pastorino, Boris A.M.; Bessaud, Maël; Gravier, Patrick; Tock, Fabienne; Couissinier-Paris, Patricia; Martial, Jenny; Huc-Anais, Patricia; Césaire, Raymond; Grandadam, Marc; Tolou, Hugues J.

    2005-01-01

    We describe the spread of a dengue virus during an outbreak in Saint Martin island (French West Indies) during winter 2003–2004. Dengue type 3 viruses were isolated from 6 patients exhibiting clinical symptoms. This serotype had not been detected on the island during the preceding 3 years. Genome sequence determinations and analyses showed a common origin with dengue type 3 viruses isolated in Martinique 2 years earlier. PMID:15890134

  18. The Clinical and Serological Profile of Pediatric Dengue.

    PubMed

    Ramabhatta, Sujatha; Palaniappan, Saravanan; Hanumantharayappa, Navya; Begum, Shaik Vajidunnisa

    2017-09-08

    To classify suspected dengue into dengue, dengue with warning signs and severe dengue, based on clinical features as per the revised WHO guidelines with special emphasis on serology. It was a prospective cross-sectional study for five years from 2011-2016 in a tertiary care medical college hospital in Bangalore. All cases of fever of three to five days duration with symptoms like dengue were enrolled for the study. They were categorized into three groups as per the Revised WHO 2012 criteria. Laboratory parameters, serology, ultrasound abdomen and X-ray were done in almost all patients. Data was analysed by SPSS software, version 16, and different groups were compared with Chi square test. Five hundred sixty eight children were diagnosed to have dengue fever; 4.2% of the sample belonged to infancy. Majority were in the age group of 5-10 y (42.6%). Fever and flushing were present in majority of the children. Gastrointestinal bleed was more commonly seen in the severe dengue group. Dengue nonstructural protein antigen (NS1Ag) was positive in 78%, immunoglobulin M (IgM) in 15.8% and immunoglobulin G (IgG) in 14.6%. Children with IgG had more complications, though not statistically significant. Mortality was reported in 1.2%. Dengue serology helped to confirm the diagnosis, however did not help in patient management. There is a considerable overlap in the symptomatology of dengue with warning signs and severe dengue. More studies are required on the severity and type of response to treatment in infants and obese adoloscents with severe dengue.

  19. The Effects of Weather and Climate Change on Dengue

    PubMed Central

    Colón-González, Felipe J.; Fezzi, Carlo; Lake, Iain R.; Hunter, Paul R.

    2013-01-01

    Background There is much uncertainty about the future impact of climate change on vector-borne diseases. Such uncertainty reflects the difficulties in modelling the complex interactions between disease, climatic and socioeconomic determinants. We used a comprehensive panel dataset from Mexico covering 23 years of province-specific dengue reports across nine climatic regions to estimate the impact of weather on dengue, accounting for the effects of non-climatic factors. Methods and Findings Using a Generalized Additive Model, we estimated statistically significant effects of weather and access to piped water on dengue. The effects of weather were highly nonlinear. Minimum temperature (Tmin) had almost no effect on dengue incidence below 5°C, but Tmin values above 18°C showed a rapidly increasing effect. Maximum temperature above 20°C also showed an increasing effect on dengue incidence with a peak around 32°C, after which the effect declined. There is also an increasing effect of precipitation as it rose to about 550 mm, beyond which such effect declines. Rising access to piped water was related to increasing dengue incidence. We used our model estimations to project the potential impact of climate change on dengue incidence under three emission scenarios by 2030, 2050, and 2080. An increase of up to 40% in dengue incidence by 2080 was estimated under climate change while holding the other driving factors constant. Conclusions Our results indicate that weather significantly influences dengue incidence in Mexico and that such relationships are highly nonlinear. These findings highlight the importance of using flexible model specifications when analysing weather–health interactions. Climate change may contribute to an increase in dengue incidence. Rising access to piped water may aggravate dengue incidence if it leads to increased domestic water storage. Climate change may therefore influence the success or failure of future efforts against dengue. PMID:24244765

  20. Enhancing the Immunogenicity of a Tetravalent Dengue DNA Vaccine

    DTIC Science & Technology

    2016-08-01

    AWARD NUMBER: W81XWH-15-2-0029 TITLE: Enhancing the Immunogenicity of a Tetravalent Dengue DNA Vaccine PRINCIPAL INVESTIGATOR: Maya...TITLE AND SUBTITLE Enhancing the Immunogenicity of a Tetravalent Dengue DNA 5a. CONTRACT NUMBER Vaccine 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...personnel is priority research area for the US DoD. Phase 1 clinical trials demonstrated that the Naval Medical Research Center’s DNA based dengue vaccine

  1. Field Evaluation of Lethal Ovitrap against Dengue Vectors

    DTIC Science & Technology

    2005-04-01

    AD Award Number: DAMD17-02-1-0217 TITLE: Field Evaluation of Lethal Ovitrap against Dengue Vectors PRINCIPAL INVESTIGATOR: Dr. Lane Foil CONTRACTING...2005 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Field Evaluation of Lethal Ovitrap against Dengue Vectors 5b. GRANT NUMBER DAMD17-02-1-0217 5c. PROGRAM...to effectively sample dengue mosquito vector populations, particularly Aedes aegypti for over a decade. Modifying a standard ovitrap by incorporating

  2. Dengue Serotypes 2 and 3 in US Forces in Somalia

    DTIC Science & Technology

    1994-01-01

    Reduction Project (0704-0 188). Wasnington. DC 20503 DATE 3. REPORT TYPE AND DATES COVERED 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Dengue serotynes 2...illnesses among US forces in Som3lia revealed dengue viruses as an important identifiable cause. 90 consecutively admitted patients temperatures of...at least 38.10 C were studied. Flavivirus infection was confirmed by positive dengue IgM and/or hemagluttinin inhibition tests in 15 of 84 individuals

  3. Meteorologically Driven Simulations of Dengue Epidemics in San Juan, PR.

    PubMed

    Morin, Cory W; Monaghan, Andrew J; Hayden, Mary H; Barrera, Roberto; Ernst, Kacey

    2015-08-01

    Meteorological factors influence dengue virus ecology by modulating vector mosquito population dynamics, viral replication, and transmission. Dynamic modeling techniques can be used to examine how interactions among meteorological variables, vectors and the dengue virus influence transmission. We developed a dengue fever simulation model by coupling a dynamic simulation model for Aedes aegypti, the primary mosquito vector for dengue, with a basic epidemiological Susceptible-Exposed-Infectious-Recovered (SEIR) model. Employing a Monte Carlo approach, we simulated dengue transmission during the period of 2010-2013 in San Juan, PR, where dengue fever is endemic. The results of 9600 simulations using varied model parameters were evaluated by statistical comparison (r2) with surveillance data of dengue cases reported to the Centers for Disease Control and Prevention. To identify the most influential parameters associated with dengue virus transmission for each period the top 1% of best-fit model simulations were retained and compared. Using the top simulations, dengue cases were simulated well for 2010 (r2 = 0.90, p = 0.03), 2011 (r2 = 0.83, p = 0.05), and 2012 (r2 = 0.94, p = 0.01); however, simulations were weaker for 2013 (r2 = 0.25, p = 0.25) and the entire four-year period (r2 = 0.44, p = 0.002). Analysis of parameter values from retained simulations revealed that rain dependent container habitats were more prevalent in best-fitting simulations during the wetter 2010 and 2011 years, while human managed (i.e. manually filled) container habitats were more prevalent in best-fitting simulations during the drier 2012 and 2013 years. The simulations further indicate that rainfall strongly modulates the timing of dengue (e.g., epidemics occurred earlier during rainy years) while temperature modulates the annual number of dengue fever cases. Our results suggest that meteorological factors have a time-variable influence on dengue transmission relative to other important

  4. Dengue Contingency Planning: From Research to Policy and Practice

    PubMed Central

    Runge-Ranzinger, Silvia; Kroeger, Axel; Olliaro, Piero; McCall, Philip J.; Sánchez Tejeda, Gustavo; Lloyd, Linda S.; Hakim, Lokman; Bowman, Leigh R.; Horstick, Olaf; Coelho, Giovanini

    2016-01-01

    Background Dengue is an increasingly incident disease across many parts of the world. In response, an evidence-based handbook to translate research into policy and practice was developed. This handbook facilitates contingency planning as well as the development and use of early warning and response systems for dengue fever epidemics, by identifying decision-making processes that contribute to the success or failure of dengue surveillance, as well as triggers that initiate effective responses to incipient outbreaks. Methodology/Principal findings Available evidence was evaluated using a step-wise process that included systematic literature reviews, policymaker and stakeholder interviews, a study to assess dengue contingency planning and outbreak management in 10 countries, and a retrospective logistic regression analysis to identify alarm signals for an outbreak warning system using datasets from five dengue endemic countries. Best practices for managing a dengue outbreak are provided for key elements of a dengue contingency plan including timely contingency planning, the importance of a detailed, context-specific dengue contingency plan that clearly distinguishes between routine and outbreak interventions, surveillance systems for outbreak preparedness, outbreak definitions, alert algorithms, managerial capacity, vector control capacity, and clinical management of large caseloads. Additionally, a computer-assisted early warning system, which enables countries to identify and respond to context-specific variables that predict forthcoming dengue outbreaks, has been developed. Conclusions/Significance Most countries do not have comprehensive, detailed contingency plans for dengue outbreaks. Countries tend to rely on intensified vector control as their outbreak response, with minimal focus on integrated management of clinical care, epidemiological, laboratory and vector surveillance, and risk communication. The Technical Handbook for Surveillance, Dengue Outbreak

  5. Cross-serotype neutralization of dengue virus in Aotus nancymae monkeys.

    PubMed

    Kochel, Tadeusz J; Watts, Douglas M; Gozalo, Alfonso S; Ewing, Daniel F; Porter, Kevin R; Russell, Kevin L

    2005-03-15

    Previously, we observed that serum from humans immune to dengue serotype 1 (dengue-1) neutralized the American genotype of dengue serotype 2 (American-2) to a greater extent than it neutralized the Asian genotype of dengue serotype 2 (Asian-2). To determine if this activity is protective, Aotus nancymae monkeys were infected with dengue-1 followed by either American-2 or Asian-2. Dengue-1-infected animals produced antibody with neutralizing titers of 2656 antibodies against dengue-1, 409 against American-2, and <20 against Asian-2. Infection with American-2 did not produce detectable viremia in either dengue-1-immune or dengue-1-naive animals. These findings support the hypothesis that dengue-1 immunity might have prevented disease or altered the severity of disease in individuals sequentially infected with dengue-1 and American-2.

  6. Dispersal strategies in sponge larvae: integrating the life history of larvae and the hydrologic component.

    PubMed

    Mariani, Simone; Uriz, María-J; Turon, Xavier; Alcoverro, Teresa

    2006-08-01

    While known to be uniformly non-feeding, short-lived, and potentially short dispersing, sponge larvae display different behaviours (swimming ability and taxis). Our aim was to show whether sponge larvae with different behaviours exhibit different dispersal strategies under variable intensity of water movements. We first assessed the distribution of larvae of six taxa: Dictyoceratida spp., Dysidea avara, Crambe crambe, Phorbas tenacior, Scopalina lophyropoda, and Cliona viridis, collected through plankton sampling, and the abundance of the corresponding adult sponges across three hard bottom communities and a sandy bottom from a north-west Mediterranean rocky shore. We then tested adult-larvae couplings (abundance of larvae vs abundance of adults) under increasing levels of water movements (surge) to assess the importance of this environmental factor in driving differences in dispersal strategies. Adults of Dictyoceratida spp., D. avara, and P. tenacior were most abundant in semi-dark caves (SDC), C. crambe and C. viridis in communities of sciaphilic algae (SA), whereas the distribution of S. lophyropoda was extremely patchy, being present almost only in the SA community of one of the five stations studied. Larvae of Dictyoceratida spp. and P. tenacior were more abundant in the SDC, whereas D. avara and C. crambe were homogeneously distributed across the communities. The larvae of C. viridis were more abundant in the SA communities and the S. lophyropoda larvae were mostly present in one station and one community (SA). Increased water movement did not modify the adult-larvae coupling for Dictyoceratida spp., D. avara, and C. crambe, whereas it broke up the positive association for P. tenacior and to some extent S. lophyropoda. For C. viridis, possible variability in adult-larvae coupling was not tested because the larvae were collected on only one day under calm sea conditions. We confirm that efficient-swimming larvae with some cue response can actively counteract

  7. Rearing Chrysoperla externa Larvae on Artificial Diets.

    PubMed

    Bezerra, C E S; Amaral, B B; Souza, B

    2017-02-01

    We tested three artificial diets for rearing larvae of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae), aiming at reducing the production costs of this predator. Two of the diets come from studies with other species of lacewings, and the third is a modification described in this paper. All diets were based on animal protein and were supplied to 2nd and 3rd instar larvae, whereas 1st instar larvae received eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae). We evaluated the preimaginal duration and survival, adult size, longevity and fecundity, egg hatchability, and predatory capacity of larvae produced. The performance of the diets was followed for seven generations. The diet we describe showed to be the best among the artificial diets tested. Our results show that C. externa can be successfully reared on artificial diets during second and third instars, reducing in 90% the dependency on eggs of A. kuehniella.

  8. [Botfly larva skin infestation in a donkey].

    PubMed

    Schumann, H; Schuster, R; Ruscher, H J

    1988-11-01

    In January 1987 7 larvae of Hypoderma diana were found in a donkey. The infection probably took place on a horse pasture in Fürstenwalde, Frankfurt (O.) region, grazed also by roes, the main hosts of H. diana.

  9. Dengue serotype surveillance among patients admitted for dengue in two major hospitals in Selangor, Malaysia, 2010-2011.

    PubMed

    Ab-Fatah, M; Subenthiran, S; Abdul-Rahman, P S A; Saat, Z; Thayan, R

    2015-03-01

    Dengue serotype surveillance is important as any changes in serotype distribution may result in an outbreak or increase in severe dengue cases. This study aimed to determine circulating dengue serotypes in two hospitals in Selangor. Serum samples were collected from patients admitted for dengue at these two major public hospitals i.e. Hospital Sungai Buloh (HSB) and Hospital Tunku Ampuan Rahimah (HTAR) between November 2010 and August 2011 and subjected to real-time RT-PCR using SYBR® Green. All four dengue serotypes were detected in samples from both hospitals. The predominating serotype was dengue 1 in samples from both hospitals (HSB, DENV-1; 25.53 % and HTAR, DENV-1; 32.1 %).

  10. The growing burden of dengue in Latin America.

    PubMed

    Tapia-Conyer, Roberto; Méndez-Galván, Jorge F; Gallardo-Rincón, Héctor

    2009-10-01

    The re-emergence and subsequent failure to control dengue in Latin America provides a compelling illustration of the clinical, political and socio-economic challenges to eradicating dengue across the world. Insufficient political commitment, inadequate financial resources and increased urbanisation have contributed to the re-emergence and dramatic increase in dengue fever and dengue haemorrhagic fever in all 19 Latin American countries previously certified as free of Aedes aegypti. Difficulties with diagnosis, asymptomatic infection and the lack of effective surveillance systems account for the discrepancies between antibody prevalence against dengue and reported cases. Accurate incidence data and appreciation of the economic impact of dengue at regional, national and international levels are essential to securing political and economic commitment for dengue control efforts as well as increased scientific and social awareness. Environmental control efforts require an integrated and systematic approach at both the national and community level, while successful introduction of a dengue vaccine will require an educational programme that clearly communicates the cost-effectiveness and desirability of this interventional measure. In addition, countries must anticipate their national regulatory requirements, and vaccination strategies should be optimised according to the dengue epidemiology of each country. A broad scope is required to finance vaccination programmes to ensure individual countries' monetary shortcomings are addressed.

  11. Latest developments and future directions in dengue vaccines

    PubMed Central

    Thisyakorn, Chule

    2014-01-01

    Dengue is a mosquito-borne disease which is currently an expanding global health problem. The disease is caused by four closely related viruses, the dengue virus. There are no specific dengue therapeutics and prevention is currently limited to vector control measures. Development of an effective tetravalent dengue vaccine would therefore represent a major advance in the control of the disease and is considered a high public health priority. While a licensed dengue vaccine is not yet available, the scope and intensity of dengue vaccine development has increased dramatically in the last decade. The uniqueness of the dengue viruses and the spectrum of disease resulting from infection have made dengue vaccine development difficult. Several vaccine candidates are currently being evaluated in clinical studies. The candidate currently at the most advanced clinical development stage, a live-attenuated tetravalent vaccine based on chimeric yellow fever dengue virus, has progressed to phase III efficacy studies. Several other live-attenuated vaccines, as well as subunit, DNA and purified inactivated vaccine candidates, are at earlier stages of clinical development. Additional technological approaches, such as virus-vectored and virus-like particle-based vaccines, are under evaluation in preclinical studies. PMID:24757522

  12. The 2012 dengue outbreak in Madeira: exploring the origins.

    PubMed

    Wilder-Smith, A; Quam, M; Sessions, O; Rocklov, J; Liu-Helmersson, J; Franco, L; Khan, K

    2014-02-27

    In 2012, Madeira reported its first major outbreak of dengue. To identify the origin of the imported dengue virus, we investigated the interconnectivity via air travel between dengue-endemic countries and Madeira, and compared available sequences against GenBank. There were 22,948 air travellers to Madeira in 2012, originating from twenty-nine dengue-endemic countries; 89.6% of these international travellers originated from Venezuela and Brazil. We developed an importation index that takes into account both travel volume and the extent of dengue incidence in the country of origin. Venezuela and Brazil had by far the highest importation indices compared with all other dengue-endemic countries. The importation index for Venezuela was twice as high as that for Brazil. When taking into account seasonality in the months preceding the onset of the Madeira outbreak, this index was even seven times higher for Venezuela than for Brazil during this time. Dengue sequencing shows that the virus responsible for the Madeira outbreak was most closely related to viruses circulating in Venezuela, Brazil and Columbia. Applying the importation index, Venezuela was identified as the most likely origin of importation of dengue virus via travellers to Madeira. We propose that the importation index is a new additional tool that can help to identify and anticipate the most probable country of origin for importation of dengue into currently non-endemic countries.

  13. Dengue virus life cycle: viral and host factors modulating infectivity.

    PubMed

    Rodenhuis-Zybert, Izabela A; Wilschut, Jan; Smit, Jolanda M

    2010-08-01

    Dengue virus (DENV 1-4) represents a major emerging arthropod-borne pathogen. All four DENV serotypes are prevalent in the (sub) tropical regions of the world and infect 50-100 million individuals annually. Whereas the majority of DENV infections proceed asymptomatically or result in self-limited dengue fever, an increasing number of patients present more severe manifestations, such as dengue hemorrhagic fever and dengue shock syndrome. In this review we will give an overview of the infectious life cycle of DENV and will discuss the viral and host factors that are important in controlling DENV infection.

  14. Agent-based modeling to simulate the dengue spread

    NASA Astrophysics Data System (ADS)

    Deng, Chengbin; Tao, Haiyan; Ye, Zhiwei

    2008-10-01

    In this paper, we introduce a novel method ABM in simulating the unique process for the dengue spread. Dengue is an acute infectious disease with a long history of over 200 years. Unlike the diseases that can be transmitted directly from person to person, dengue spreads through a must vector of mosquitoes. There is still no any special effective medicine and vaccine for dengue up till now. The best way to prevent dengue spread is to take precautions beforehand. Thus, it is crucial to detect and study the dynamic process of dengue spread that closely relates to human-environment interactions where Agent-Based Modeling (ABM) effectively works. The model attempts to simulate the dengue spread in a more realistic way in the bottom-up way, and to overcome the limitation of ABM, namely overlooking the influence of geographic and environmental factors. Considering the influence of environment, Aedes aegypti ecology and other epidemiological characteristics of dengue spread, ABM can be regarded as a useful way to simulate the whole process so as to disclose the essence of the evolution of dengue spread.

  15. Recent expansion of dengue virus serotype 3 in West Africa.

    PubMed

    Franco, L; Di Caro, A; Carletti, F; Vapalahti, O; Renaudat, C; Zeller, H; Tenorio, A

    2010-02-18

    Due to non-existing or limited surveillance in Africa, little is known about the epidemiology of dengue illness in the continent. Serological and virological data obtained from returning European travellers is a key complement to this often flawed information. In the past years, dengue 3 virus has emerged in West Africa and has been detected in travellers returning to Europe. The first dengue epidemic in Cape Verde with more than 17,000 cases from September to December 2009 demonstrated that dengue virus is still expanding worldwide to new territories.

  16. Investigational drugs in early development for treating dengue infection.

    PubMed

    Beesetti, Hemalatha; Khanna, Navin; Swaminathan, Sathyamangalam

    2016-09-01

    Dengue has emerged as the most significant arboviral disease of the current century. A drug for dengue is an urgent unmet need. As conventional drug discovery efforts have not produced any promising clinical candidates, there is a shift toward re-positioning pre-existing drugs for dengue to fast-track dengue drug development. This article provides an update on the current status of recently completed and ongoing dengue drug trials. All dengue drug trials described in this article were identified from a list of >230 trials that were returned upon searching the World Health Organization's International Clinical Trials Registry Platform web portal using the search term 'dengue' on December 31(st), 2015. None of the handful of drugs tested so far has yielded encouraging results. Early trial experience has served to emphasize the challenge of drug testing in the short therapeutic time window available, the need for tools to predict 'high-risk' patients early on and the limitations of the existing pre-clinical model systems. Significant investment of efforts and resources is a must before the availability of a safe, effective and inexpensive dengue drug becomes a reality. Currently, supportive fluid therapy remains the only option available for dengue treatment.

  17. Serological Evidence of Dengue Fever Among Refugees, Hargeysa, Somalia

    DTIC Science & Technology

    1989-01-01

    AD-A24 1 179 Q O0T!119910 j •___ C PUBLICATION REPORT 1602 84/89-90 SEROLOGICAL EVIDENCE OF DENGUE FEVER AMONG REFUGEES, HARGEYOA, SOMALIA BY Boulos...of Dengue Fever Among Refugees, Hargeysa, Somalia Boulos A.M. Botros, Douglas M. Watts, Atef K. Soliman, Adel W. Salib, Mahmoud I. Moussa, H. Mursal...Tukei PM 1982). Epidemic Dengue fever caused by Dengue tion, antibody demonstrated by the EIA, IFA, and HI type-2 virus in Kenya: Preliminary results

  18. Dengue fever mimicking acute appendicitis: A case report.

    PubMed

    McFarlane, M E C; Plummer, J M; Leake, P A; Powell, L; Chand, V; Chung, S; Tulloch, K

    2013-01-01

    Dengue fever is an acute viral disease, which usually presents as a mild febrile illness. Patients with severe disease present with dengue haemorrhagic fever or dengue toxic shock syndrome. Rarely, it presents with abdominal symptoms mimicking acute appendicitis. We present a case of a male patient presenting with right iliac fossa pain and suspected acute appendicitis that was later diagnosed with dengue fever following a negative appendicectomy. A 13-year old male patient presented with fever, localized right-sided abdominal pain and vomiting. Abdominal ultrasound was not helpful and appendicectomy was performed due to worsening abdominal signs and an elevated temperature. A normal appendix with enlarged mesenteric nodes was found at surgery. Complete blood count showed thrombocytopenia with leucopenia. Dengue fever was now suspected and confirmed by IgM enzyme-linked immunosorbent assay against dengue virus. This unusual presentation of dengue fever mimicking acute appendicitis should be suspected during viral outbreaks and in patients with atypical symptoms and cytopenias on blood evaluation in order to prevent unnecessary surgery. This case highlights the occurrence of abdominal symptoms and complications that may accompany dengue fever. Early recognition of dengue fever mimicking acute appendicitis will avoid non-therapeutic operation and the diagnosis may be aided by blood investigations indicating a leucopenia, which is uncommon in patients with suppurative acute appendicitis. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Seir Model for Transmission of Dengue Fever in Selangor Malaysia

    NASA Astrophysics Data System (ADS)

    Syafruddin, S.; Noorani, M. S. M.

    In this paper, we study a system of differential equations that models the population dynamics of SEIR vector transmission of dengue fever. The model studied breeding value based on the number of reported cases of dengue fever in Selangor because the state had the highest case in Malaysia. The model explains that maximum level of human infection rate of dengue fever achieved in a very short period. It is also revealed that there existed suitability result between theoretical and empirical calculation using the model. The result of SEIR model will hopefully provide an insight into the spread of dengue fever in Selangor Malaysia and basic form for modeling this area.

  20. Clinical and Virological Features of Dengue in Vietnamese Infants

    PubMed Central

    Bich Chau, Tran Nguyen; Anders, Katherine L.; Lien, Le Bich; Hung, Nguyen Thanh; Minh Hieu, Lu Thi; Tuan, Nguyen Minh; Thuy, Tran Thi; Phuong, Le Thi; Hong Tham, Nguyen Thi; Lanh, Mai Ngoc; Farrar, Jeremy J.; Whitehead, Stephen S.; Simmons, Cameron P.

    2010-01-01

    Background Infants account for a small proportion of the overall dengue case burden in endemic countries but can be clinically more difficult to manage. The clinical and laboratory features in infants with dengue have not been extensively characterised. Methodology/Principal Findings This prospective, cross-sectional descriptive study of infants hospitalized with dengue was conducted in Vietnam from November 2004 to December 2007. More than two-thirds of 303 infants enrolled on clinical suspicion of dengue had a serologically confirmed dengue virus (DENV) infection. Almost all were primary dengue infections and 80% of the infants developed DHF/DSS. At the time of presentation and during hospitalization, the clinical signs and symptoms in infants with dengue were difficult to distinguish from those with other febrile illnesses, suggesting that in infants early laboratory confirmation could assist appropriate management. Detection of plasma NS1 antigen was found to be a sensitive marker of acute dengue in infants with primary infection, especially in the first few days of illness. Conclusions/Significance Collectively, these results provide a systematic description of the clinical features of dengue in infants and highlight the value of NS1 detection for diagnosis. PMID:20405057

  1. Transverse Myelitis as an Unusual Complication of Dengue Fever.

    PubMed

    Mota, Mânlio Tasso de Oliveira; Estofolete, Cássia Fernanda; Zini, Nathalia; Terzian, Ana Carolina Bernardes; Gongora, Delzi Vinha Nunes; Maia, Irineu Luiz; Nogueira, Maurício Lacerda

    2017-02-08

    Dengue fever is the most common arbovirus disease, and presents with a large spectrum of clinical manifestations ranging from asymptomatic disease through to the development of dengue hemorrhagic fever. These extreme cases can lead to dengue shock syndrome, and sometimes death. Spinal cord involvement in dengue virus (DENV) infections is rare. Here, we report a case in which the patient developed acute transverse myelitis (TM) without paraparesis following a DENV infection. This case highlights the importance of physicians' awareness of the possible link between DENV and TM in endemic areas.

  2. Dengue fever in the San Juan Bay Estuary: Evaluating the ...

    EPA Pesticide Factsheets

    Dengue is transmitted by Aedes aegypti, a species that thrives in cities. Here we ask which elements within the urban environment could be managed to reduce the potential for Dengue occurrence. In particular, we study the potential of wetlands in the SJBE to buffer from vector proliferation. Wetlands provide ecosystem services such as heat and water hazard mitigation, water purification and habitat for a diversity of species, all of which are factors that have been shown to affect Dengue vectors. As such, we hypothesize that within coastal neighborhoods in the SJBE wetlands, ecosystem services lead to lower Dengue occurrence. We test this hypothesis using Dengue data from 2010-2013, which includes the largest epidemic in PR history. Our analytical model includes relevant socio-economic factors and environmental controls that may also affect Dengue dynamics. Results indicated a negative effect of neighborhood mangrove cover and a positive effect of percent flood area on Dengue prevalence. Moreover, heat hazards were positively correlated with dengue prevalence and negatively correlated with neighborhood mangrove cover. Dengue prevalence did not correlate with herbaceous wetlands, or with the ecosystem services of water quality or vertebrate species richness. Mosquito borne diseases are an increasingly important health concern, which pose great challenges for safe and sustainable control and eradication. This reality calls for management approaches that consider m

  3. Epidemiological trends of dengue in mainland China, 2005-2015.

    PubMed

    Sun, Jimin; Lu, Liang; Wu, Haixia; Yang, Jun; Xu, Lei; Sang, Shaowei; Liu, Qiyong

    2017-04-01

    To explore the epidemiological trend of dengue in mainland China. Data on dengue cases reported from 2005 to 2015 were collected, and epidemiological trends, including average age, occupation, seasonal distribution, and interval from illness onset to confirmation, were analyzed using SPSS 19.0 and R 3.1.1. A total of 59 334 dengue cases were recorded in China during the years 2005-2015. Most dengue cases occurred in individuals aged between 21 years and 50 years. Of note, the median age of dengue cases did not show a trend towards becoming younger; the median age was significantly older than that of cases in dengue endemic areas. The proportion of cases occurring during September and October was higher in 2012-2015 than in 2005-2011. The number of affected provinces ranged between 10 and 27 and the number of affected counties ranged between 42 and 415. The median time from illness onset to confirmation of dengue decreased sharply in 2015, indicating that comprehensive measures have been taken in mainland China. Although the number of dengue cases has increased and the affected areas have expanded in recent years, dengue is still an imported disease and does not present an endemic trend in mainland China. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  4. Antiviral activity of lanatoside C against dengue virus infection.

    PubMed

    Cheung, Yan Yi; Chen, Karen Caiyun; Chen, Huixin; Seng, Eng Khuan; Chu, Justin Jang Hann

    2014-11-01

    Dengue infection poses a serious threat globally due to its recent rapid spread and rise in incidence. Currently, there is no approved vaccine or effective antiviral drug for dengue virus infection. In response to the urgent need for the development of an effective antiviral for dengue virus, the US Drug Collection library was screened in this study to identify compounds with anti-dengue activities. Lanatoside C, an FDA approved cardiac glycoside was identified as a candidate anti-dengue compound. Our data revealed that lanatoside C has an IC50 of 0.19μM for dengue virus infection in HuH-7 cells. Dose-dependent reduction in dengue viral RNA and viral proteins synthesis were also observed upon treatment with increasing concentrations of lanatoside C. Time of addition study indicated that lanatoside C inhibits the early processes of the dengue virus replication cycle. Furthermore, lanatoside C can effectively inhibit all four serotypes of dengue virus, flavivirus Kunjin, alphavirus Chikungunya and Sindbis virus as well as the human enterovirus 71. These findings suggest that lanatoside C possesses broad spectrum antiviral activity against several groups of positive-sense RNA viruses.

  5. Infection risk to travelers going to dengue fever endemic regions.

    PubMed

    Pongsumpun, P; Patanarapelert, K; Sriprom, M; Varamit, S; Tang, I M

    2004-03-01

    The risk of dengue virus infection to travelers visiting dengue fever endemic regions was studied through the use of mathematical modeling. A Susceptible-Infected-Recovered (SIR) model is used to describe the transmission of dengue fever (DF) in an endemic region into which tourists enter. The dynamics of a new class of human, the traveler, is incorporated into the systems of first order differential equations in the SIR describing the dynamics of the transmission in the host region. Using standard dynamic analysis methods, the numbers of travelers who become infected with the dengue virus are calculated as a function of the length of time the tourist stays in the region.

  6. STUDIES UPON THE ETIOLOGY OF DENGUE FEVER

    PubMed Central

    Harris, William H.; Duval, Charles W.

    1924-01-01

    The dengue cases studied during this epidemic were, as a whole, typical examples of the disease. The onset was sudden, often of a violent character, ushered in with severe headache and backache, vague pains throughout the body, and fever ranging from 101–105°F. On the 2nd or 3rd day a maculopapular eruption appeared, generally on the neck, chest, and arms, but sometimes more widely disseminated. In most instances the fever remained for 3 or 4 days, after which it dropped to normal to rise again in 24 to 48 hours. The secondary rise, while occasionally higher than the primary one, was as a rule of a milder character. A few cases occurred in which marked jaundice existed. As reported for previous epidemics, no fatalities were recorded and hence no human material for histological study was available. Those cases caught in the fastigium of the disease were selected when possible as a source of material. The leucocytic count in all of the observed human cases was below normal. The experiments herein reported upon the transmission of dengue fever to the guinea pig are based upon the use of material secured from sixteen typical human cases of the disease, and upon the inoculation of many animals. Of the 143 animals used for the initial transmission, 42, representing eleven human cases out of the sixteen studied, reacted in a characteristic manner. The reaction occasioned in these animals by the inoculations closely resembles the symptoms seen in human dengue, differing only in the absence of exanthem. The primary pyrexia following regularly after a definite incubation period of 2 to 5 days, the secondary rise in temperature after a 24 to 48 hour remission ("saddleback"curve), and the concomitant fall in the circulating leucocytes present a syndrome identical with that of the human disease. Dark-field and special tinctorial studies of the dengue material, both human and experimental, have failed to reveal any visible spirochetal microorganism. It seems unlikely that an

  7. Activity of R(+) Limonene Against Anisakis Larvae

    PubMed Central

    Muscolino, Daniele; Panebianco, Felice; Patania, Andrea; Benianti, Chiara; Ziino, Graziella; Giuffrida, Alessandro

    2015-01-01

    The aim of this work is to evaluate the activity of R(+) limonene of against Anisakidae larvae. Its effectiveness was tested in vitro. The results obtained showed a significant activity of the compound against Anisakis larvae, suggesting further investigation on its potential use in the industrial marinating process. In this regard, the use of R(+) limonene in seafood products could be interesting, also due the sensory attributes resulting from its use and its relatively safe status. PMID:27800423

  8. Activity of R(+) Limonene Against Anisakis Larvae.

    PubMed

    Giarratana, Filippo; Muscolino, Daniele; Panebianco, Felice; Patania, Andrea; Benianti, Chiara; Ziino, Graziella; Giuffrida, Alessandro

    2015-11-02

    The aim of this work is to evaluate the activity of R(+) limonene of against Anisakidae larvae. Its effectiveness was tested in vitro. The results obtained showed a significant activity of the compound against Anisakis larvae, suggesting further investigation on its potential use in the industrial marinating process. In this regard, the use of R(+) limonene in seafood products could be interesting, also due the sensory attributes resulting from its use and its relatively safe status.

  9. A Case Report of Cutaneous Larva Migrans

    PubMed Central

    Yavuzer, Kemal; Ak, Muharrem; Karadag, Ayse Serap

    2010-01-01

    Cutaneous larva migrans (CLM) is a helminthic infection most commonly found in tropical and subtropical geographic areas. However, with the ease and increase of foreign travel by many around the world, CLM is no longer confined to these areas. CLM is an erythematous, serpiginous, cutaneous eruption caused by accidental percutaneous penetration and subsequent migration of larvae. Here, we present a case diagnosed as CLM and treated with Albendazole. PMID:25610118

  10. [Toxic activity of Bacillus Thuringiensis isolates to Aedes Aegypti (L.) (Diptera: Culicidae) larvae].

    PubMed

    da Costa, Juliana R V; Rossi, Juliana R; Marucci, Suzana C; da C Alves, Eliane C; Volpe, Haroldo X L; Ferraudo, Antonio S; Lemos, Manoel V F; Desidério, Janete A

    2010-01-01

    Aedes aegypti (L.), the main vector of dengue fever in Brazil, has been controlled with the use of massive chemical products, contributing to the development of resistance and decreasing the insect control efficiency. The control of dipterans with bioinsecticides based on Bacillus thuringiensis has been satisfactory, due to the production of insecticidal proteins denominated Cry (crystal), Cyt (cytolytic) toxins and Chi (chitinase), and to the synergistic effects among them. The present work aimed to select B. thuringiensis isolates efficient against A. aegypti larvae. A bacterial collection containing 1,073 isolates of B. thuringiensis, obtained from different locations of Brazilian territory, had the DNA isolated and submitted to PCR amplifications using specific primers for cry4Aa, cry4Ba, cry11Aa, cry11Ba, cyt1Aa, cyt1Ab, cyt2Aa and chi genes. For the LC50 and LC90 determination, the entomopathogenic isolates were evaluated by selective and quantitative bioassays. Only 45 isolates (4.2%) presented amplicons for the cry and cyt genes. The chi gene sequence was detected in 25 (54.3%) of those isolates. From the 45 isolates submitted to the selective bioassays, 13 caused 100% mortality of A. aegypti larvae. The identification of cry, cyt and chi genes of B. thuringiensis and the toxicity analysis on A. aegypti led to the selection of a set of isolates that have the potential to be used in the formulation of new bioinsecticides.

  11. Control of aedes vectors of dengue in three provinces of Vietnam by use of Mesocyclops (Copepoda) and community-based methods validated by entomologic, clinical, and serological surveillance.

    PubMed

    Kay, Brian H; Nam, Vu Sinh; Tien, Tran Van; Yen, Nguyen Thi; Phong, Tran Vu; Diep, Vu Thi Bich; Ninh, Truong Uyen; Bektas, Ahmet; Aaskov, John G

    2002-01-01

    We describe remarkable success in controlling dengue vectors, Aedes aegypti (L.) and Aedes albopictus (Skuse), in 6 communes with 11,675 households and 49,647 people in the northern provinces of Haiphong, Hung Yen, and Nam Dinh in Vietnam. The communes were selected for high-frequency use of large outdoor concrete tanks and wells. These were found to be the source of 49.6-98.4% of Ae. aegypti larvae, which were amenable to treatment with local Mesocyclops, mainly M. woutersi Van der Velde, M. aspericornis (Daday) and M. thermocyclopoides Harada. Knowledge, attitude, and practice surveys were performed to determine whether the communities viewed dengue and dengue hemorrhagic fever as a serious health threat; to determine their knowledge of the etiology, attitudes, and practices regarding control methods including Mesocyclops; and to determine their receptivity to various information methods. On the basis of the knowledge, attitude, and practice data, the community-based dengue control program comprised a system of local leaders, health volunteer teachers, and schoolchildren, supported by health professionals. Recycling of discards for economic gain was enhanced, where appropriate, and this, plus 37 clean-up campaigns, removed small containers unsuitable for Mesocyclops treatment. A previously successful eradication at Phan Boi village (Hung Yen province) was extended to 7 other villages forming Di Su commune (1,750 households) in the current study. Complete control was also achieved in Nghia Hiep (Hung Yen province) and in Xuan Phong (Nam Dinh province); control efficacy was > or = 99.7% in the other 3 communes (Lac Vien in Haiphong, Nghia Dong, and Xuan Kien in Nam Dinh). Although tanks and wells were the key container types of Ae. aegypti productivity, discarded materials were the source of 51% of the standing crop of Ae. albopictus. Aedes albopictus larvae were eliminated from the 3 Nam Dinh communes, and 86-98% control was achieved in the other 3 communes

  12. Elimination of dengue by community programs using Mesocyclops(Copepoda) against Aedes aegypti in central Vietnam.

    PubMed

    Vu, Sinh Nam; Nguyen, Thi Yen; Tran, Vu Phong; Truong, Uyen Ninh; Le, Quyen Mai; Le, Viet Lo; Le, Trung Nghia; Bektas, Ahmet; Briscombe, Alistair; Aaskov, John G; Ryan, Peter A; Kay, Brian H

    2005-01-01

    From September 2000 to June 2003, a community-based program for dengue control using local predacious copepods of the genus Mesocyclops was conducted in three rural communes in the central Vietnam provinces of Quang Nam, Quang Ngai, and Khanh Hoa. Post-project, three subsequent entomologic surveys were conducted until March 2004. The number of households and residents in the communes were 5,913 and 27,167, respectively, and dengue notification rates for these communes from 1996 were as high as 2,418.5 per 100,000 persons. Following knowledge, attitude, and practice evaluations, surveys of water storage containers indicated that Mesocyclops spp. already occurred in 3-17% and that large tanks up to 2,000 liters, 130-300-liter jars, wells, and some 220-liter metal drums were the most productive habitats for Aedes aegypti. With technical support, the programs were driven by communal management committees, health collaborators, schoolteachers, and pupils. From quantitative estimates of the standing crop of third and fourth instars from 100 households, Ae. aegypti were reduced by approximately 90% by year 1, 92.3-98.6% by year 2, and Ae. aegypti immature forms had been eliminated from two of three communes by June 2003. Similarly, from resting adult collections from 100 households, densities were reduced to 0-1 per commune. By March 2004, two communes with no larvae had small numbers but the third was negative; one adult was collected in each of two communes while one became negative. Absolute estimates of third and fourth instars at the three intervention communes and one left untreated had significant correlations (P = 0.009-< 0.001) with numbers of adults aspirated from inside houses on each of 15 survey periods. By year 1, the incidence of dengue disease in the treated communes was reduced by 76.7% compared with non-intervention communes within the same districts, and no dengue was evident in 2002 and 2003, compared with 112.8 and 14.4 cases per 100,000 at district

  13. Immunofluorescent antibody staining of intact Drosophila larvae.

    PubMed

    Manning, Laurina; Doe, Chris Q

    2017-01-01

    Antibody staining is a vital technique for studying the development of many model organisms, including Drosophila. Reliable protocols have long been available for antibody staining of Drosophila whole-mount embryos and dissected larvae. By contrast, methods for staining whole larvae have rarely been reported, are unreliable, and fail to work on large third-instar larvae. This has become a major limitation to understanding the role of multitissue interactions such as neural circuit formation and cell metastasis. We have modified existing embryo protocols to develop a reliable method for antibody staining of whole Drosophila larvae of any developmental stage. The procedure consists of a bleach wash, enzymatic digestion, first fixation, 'cracking', second fixation, (optional) Proteinase K (Pro-K) or sonication treatment, antibody staining, clearing, and mounting. The method takes longer than typical antibody stains of dissected larval tissues-12 or 16 d, depending on the size of the larvae, compared with 2-3 d for embryos or dissected tissue stains-but time is saved by eliminating the need for larval dissections and by allowing hundreds of larvae to be batch-processed. The method also works well for staining embryos, even late-stage embryos with cuticles, allowing characterization from early embryogenesis to the end of larval development.

  14. Safety Testing of Dengue-1 and Dengue-3 Seeds for Human Challenges, Unattenuated; Hepatitis A Virus, Strain HM-175

    DTIC Science & Technology

    1989-03-21

    Frederick, Maryland 21701-5012 ELEMENT NO. NO. 3M1- NO.N. I62770A 162770A870 I AC 029 (U) Safety Testing of Dengue -1 and Dengue -3 Seeds for Human...Conwu on F~vwn it Rtconat and .ewoy by block IIUW*bS)r FIELD GROUP SUl.GROUP 06 13 -- i engue-l; Dengue -3; Hepatitis A; Viral seeds; Vacn-,1A 19. ABSTRACT

  15. Vector dynamics and transmission of dengue virus: implications for dengue surveillance and prevention strategies: vector dynamics and dengue prevention.

    PubMed

    Scott, Thomas W; Morrison, Amy C

    2010-01-01

    Accounting for variation in mosquito vector populations will improve dengue surveillance and prevention. Because Aedes aegypti, the principle dengue virus (DENV) vector, transmit the virus with remarkable efficiency, entomological thresholds are especially low. Assessing risk of human infection based on immature mosquito indices has proven difficult. Greater emphasis should be placed on relative abundance of adult vectors in relation to human serotype-specific herd immunity, introduction of unique viruses, mosquito-human contact and weather. The most appropriate spatial scale for assessing entomological risk is the individual household. The scale for measuring DENV transmission risk has yet to be determined but is clearly larger than the household and likely to exceed several city blocks. Because households are expected to be a primary site for human DENV infection, intradomicile vector control strategies should be a priority, especially when the force of transmission is high. The most effective intervention strategy will combine vector control with vaccine delivery for rapid and sustained disease prevention.

  16. Acute Renal Failure in Dengue Infection

    PubMed Central

    Subramanyam, Nambakam Tanuja

    2017-01-01

    Introduction Acute Renal Failure (RF) is a rare but well recognized complication of Dengue Infection (DI). There has been paucity of published data regarding renal involvement in DI. Aim The aim of the present study was to elucidate different clinical presentations, disease outcomes of DI. To study the frequency, severity and predictors of RF in DI. Materials and Methods Patients diagnosed either as Dengue Fever (DF) or Dengue Haemorrhagic Fever/Dengue Shock Syndrome (DHF/DSS) respectively were enrolled for this study. The diagnostic criteria for DI were febrile illness associated with one of the following: 1) detection of dengue-specific IgM capture antibody or Non-Structural Protein1 (NS1) antigen; or 2) a four-fold or greater increase of dengue-specific IgG capture antibody by ELISA and haemoagglutination inhibition assay. Patients were diagnosed as having Acute RF, if serum creatinine was >1.2 mg/dl or who showed improvement by 50% in serum creatinine from the initial value. It is an observational study of medical charts, data of age, gender, and medical history of any underlying diseases in association with the severity of DI of each patient recorded. All of the laboratory results were collected. Parameters that influenced the clinical presentations and outcomes for development of classical DF or DHF/DSS in patients with or without RF were analysed and compared. Descriptive and inferential statistical analysis was carried. The Statistical software namely SAS 9.2, SPSS 15.0, Stata 10.1, Med Calc 9.0.1, Systat 12.0 and R environment ver.2.11.1 were used. Results Most common symptoms were fever followed by headache and pain in abdomen. Among the patients with RF, all patients had recovery. The patients with DHF/DSS were more susceptible to develop renal failure compared to DF group. There were statistically significant higher frequencies of renal failure, haemoconcentration, thrombocytopenia, low serum cholesterol. Patients in the RF group also had significantly

  17. Urban mosquito species (Diptera: Culicidae) of dengue endemic communities in the Greater Puntarenas area, Costa Rica