Science.gov

Sample records for trypanosomiasis vector control

  1. Control of human African trypanosomiasis in the Quiçama focus, Angola.

    PubMed Central

    Ruiz, José Antonio; Simarro, Pere P.; Josenando, Teofilo

    2002-01-01

    OBJECTIVE: To update the epidemiological status of human African trypanosomiasis (HAT), also known as sleeping sickness, in the Quiçama focus, province of Bengo, Angola, and to establish a HAT control programme. METHODS: In 1997, 8796 people (the population of 31 villages) were serologically screened for Trypanosoma brucei gambiense, the causative agent of HAT. In 1998 and 1999, surveys were carried out in villages where HAT cases had been identified in 1997. Individuals were screened using the card agglutination trypanosomiasis test (CATT), and then examined for the presence of the parasite. CATT- positive individuals in whom the presence of the parasite could not be confirmed were further tested with the CATT using serum dilutions, and those with a positive antibody end titre of 1-in-4 or above were followed-up. Patients with < or =10 white cells/micro l and no trypanosomes in their cerebrospinal fluid (CSF) were classified as being in the first stage of the disease. Vector control was not considered necessary or feasible. FINDINGS: The main transmission areas were on the Kwanza riverbanks, where 5042 inhabitants live. In 1997, the HAT prevalence was 1.97%, but this decreased to 0.55% in 1998 and to 0.33% in 1999. The relapse rate was 3% in patients treated with pentamidine and 3.5% in patients treated with melarsoprol. In patients treated with pentamidine, there was no difference in the relapse rate for patients with initial CSF white cell counts of 0-5 cells/ micro l or 6-10 cells/micro l. The overall mortality rate was 0.6% and the rate of reactive arsenical encephalopathy among the melarsoprol-treated patients was 1.7%. CONCLUSION: The epidemiological status of the disease was updated and the transmission areas were defined. The control methods implemented allowed the disease prevalence to be reduced. PMID:12378293

  2. Genome Sequence of the Tsetse Fly (Glossina morsitans): Vector of African Trypanosomiasis

    PubMed Central

    2014-01-01

    Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe the sequence and annotation of the 366-megabase Glossina morsitans morsitans genome. Analysis of the genome and the 12,308 predicted protein–encoding genes led to multiple discoveries, including chromosomal integrations of bacterial (Wolbachia) genome sequences, a family of lactation-specific proteins, reduced complement of host pathogen recognition proteins, and reduced olfaction/chemosensory associated genes. These genome data provide a foundation for research into trypanosomiasis prevention and yield important insights with broad implications for multiple aspects of tsetse biology. PMID:24763584

  3. Predicting the effect of climate change on African trypanosomiasis: integrating epidemiology with parasite and vector biology.

    PubMed

    Moore, Sean; Shrestha, Sourya; Tomlinson, Kyle W; Vuong, Holly

    2012-05-01

    Climate warming over the next century is expected to have a large impact on the interactions between pathogens and their animal and human hosts. Vector-borne diseases are particularly sensitive to warming because temperature changes can alter vector development rates, shift their geographical distribution and alter transmission dynamics. For this reason, African trypanosomiasis (sleeping sickness), a vector-borne disease of humans and animals, was recently identified as one of the 12 infectious diseases likely to spread owing to climate change. We combine a variety of direct effects of temperature on vector ecology, vector biology and vector-parasite interactions via a disease transmission model and extrapolate the potential compounding effects of projected warming on the epidemiology of African trypanosomiasis. The model predicts that epidemics can occur when mean temperatures are between 20.7°C and 26.1°C. Our model does not predict a large-range expansion, but rather a large shift of up to 60 per cent in the geographical extent of the range. The model also predicts that 46-77 million additional people may be at risk of exposure by 2090. Future research could expand our analysis to include other environmental factors that influence tsetse populations and disease transmission such as humidity, as well as changes to human, livestock and wildlife distributions. The modelling approach presented here provides a framework for using the climate-sensitive aspects of vector and pathogen biology to predict changes in disease prevalence and risk owing to climate change. PMID:22072451

  4. A review of recent knowledge of the ecology of the main vectors of trypanosomiasis*

    PubMed Central

    Langridge, W. P.; Kernaghan, R. J.; Glover, P. E.

    1963-01-01

    In this survey of recent ecological research on the main vectors of trypanosomiasis in those countries of East, Central and West Africa that are not predominantly French-speaking, the authors, after outlining the distribution of tsetse flies and the type of country in which they occur, discuss the direct and indirect effects of climate on these insects—particularly on their physiological water balance and on pupal fat reserves—and their recent advances into new areas. They review the considerable work that has been done on the resting habits and breeding-sites of different Glossina species, knowledge of which is important for effective control, and research on predators of pupae and adult flies and on the feeding activity of tsetse flies. Means of assessing populations and various factors affecting the size and nutritional status of tsetse flies are also discussed, as is the effect on the fly population of artificial changes in the habitat. Finally, a plea is made for a revision of present methods of land use and stock management, if full advantage is to be taken of achievements in fly control. PMID:13928678

  5. Challenges facing the elimination of sleeping sickness in west and central Africa: sustainable control of animal trypanosomiasis as an indispensable approach to achieve the goal.

    PubMed

    Simo, Gustave; Rayaisse, Jean Baptiste

    2015-01-01

    African trypanosomiases are infectious diseases caused by trypanosomes. African animal trypanosomiasis (AAT) remains an important threat for livestock production in some affected areas whereas human African trypanosomiasis (HAT) is targeted for elimination in 2020. In West and Central Africa, it has been shown that the parasites causing these diseases can coexist in the same tsetse fly or the same animal. In such complex settings, the control of these diseases must be put in the general context of trypanosomiasis control or "one health" concept where the coordination of control operations will be beneficial for both diseases. In this context, implementing control activities on AAT will help to sustain HAT control. It will also have a positive impact on animal health and economic development of the regions. The training of inhabitants on how to implement and sustain vector control tools will enable a long-term sustainability of control operations that will lead to the elimination of HAT and AAT. PMID:26671582

  6. Ecology of a vector-borne zoonosis in a complex ecosystem: trypanosomiasis in Serengeti, Tanzania 

    E-print Network

    Auty, Harriet K.

    2009-01-01

    Unravelling the complexities of a disease with multiple wildlife host and multiple tsetse vector species is no easy task. After over a century of field observations, experimental studies, anecdotal evidence and conjecture, ...

  7. Implications of Heterogeneous Biting Exposure and Animal Hosts on Trypanosomiasis brucei gambiense Transmission and Control

    PubMed Central

    Stone, Chris M.; Chitnis, Nakul

    2015-01-01

    The gambiense form of sleeping sickness is a neglected tropical disease, which is presumed to be anthroponotic. However, the parasite persists in human populations at levels of considerable rarity and as such the existence of animal reservoirs has been posited. Clarifying the impact of animal host reservoirs on the feasibility of interrupting sleeping sickness transmission through interventions is a matter of urgency. We developed a mathematical model allowing for heterogeneous exposure of humans to tsetse, with animal populations that differed in their ability to transmit infections, to investigate the effectiveness of two established techniques, screening and treatment of at-risk populations, and vector control. Importantly, under both assumptions, an integrated approach of human screening and vector control was supported in high transmission areas. However, increasing the intensity of vector control was more likely to eliminate transmission, while increasing the intensity of human screening reduced the time to elimination. Non-human animal hosts played important, but different roles in HAT transmission, depending on whether or not they contributed as reservoirs. If they did not serve as reservoirs, sensitivity analyses suggested their attractiveness may instead function as a sink for tsetse bites. These outcomes highlight the importance of understanding the ecological and environmental context of sleeping sickness in optimizing integrated interventions, particularly for moderate and low transmission intensity settings. PMID:26426854

  8. [American human trypanosomiasis 90 years after its discovery by Carlos Chagas. I. Epidemiology and control].

    PubMed

    Pays, J F

    1998-01-01

    It was in 1909 that Carlos Chagas described the disease which now bears his name. During the ensuing 90 years, our knowledge of this apparently whimsical, protozoan disease has grown enormously but many points remain unclear. Epidemiologically speaking, current knowledge is poor about the mechanisms and markers of variability of Trypanosoma cruzi, mechanisms allowing the organism to survive in the host, and susceptibility of infected individuals to disabling or fatal late complications. With regard to vector control, it is increasingly obvious that success will be more difficult than previously thought due to the likelihood that, as domestic species are exterminated, they will be replaced by semi-domesticated or wild species. Two other factors that have significantly changed the conventional epidemiological profile of Chagas'disease on the subcontinent over the past 50 years are human intervention in the environment and population migration from rural to urban zones. Despite the breakthroughs achieved in the last decade. Chagas'disease, with its multiple modes of transmission (vector-borne, congenital, and transfusional to name but the most important), diverse reservoir involving over 175 species, and potential for course of the disease in man, will remain a major health problem in Latin America countries for many years to come. PMID:10399701

  9. Improvements on Restricted Insecticide Application Protocol for Control of Human and Animal African Trypanosomiasis in Eastern Uganda

    PubMed Central

    Muhanguzi, Dennis; Picozzi, Kim; Hatendorf, Jan; Thrusfield, Michael; Welburn, Susan Christina; Kabasa, John David; Waiswa, Charles

    2014-01-01

    Background African trypanosomes constrain livestock and human health in Sub-Saharan Africa, and aggravate poverty and hunger of these otherwise largely livestock-keeping communities. To solve this, there is need to develop and use effective and cheap tsetse control methods. To this end, we aimed at determining the smallest proportion of a cattle herd that needs to be sprayed on the legs, bellies and ears (RAP) for effective Human and Animal African Trypanosomiasis (HAT/AAT) control. Methodology/Principal finding Cattle in 20 villages were ear-tagged and injected with two doses of diminazene diaceturate (DA) forty days apart, and randomly allocated to one of five treatment regimens namely; no treatment, 25%, 50%, 75% monthly RAP and every 3 month Albendazole drench. Cattle trypanosome re-infection rate was determined by molecular techniques. ArcMap V10.3 was used to map apparent tsetse density (FTD) from trap catches. The effect of graded RAP on incidence risk ratios and trypanosome prevalence was determined using Poisson and logistic random effect models in R and STATA V12.1 respectively. Incidence was estimated at 9.8/100 years in RAP regimens, significantly lower compared to 25.7/100 years in the non-RAP regimens (incidence rate ratio: 0.37; 95% CI: 0.22–0.65; P<0.001). Likewise, trypanosome prevalence after one year of follow up was significantly lower in RAP animals than in non-RAP animals (4% vs 15%, OR: 0.20, 95% CI: 0.08–0.44; P<0.001). Contrary to our expectation, level of protection did not increase with increasing proportion of animals treated. Conclusions/significance Reduction in RAP coverage did not significantly affect efficacy of treatment. This is envisaged to improve RAP adaptability to low income livestock keepers but needs further evaluation in different tsetse challenge, HAT/AAT transmission rates and management systems before adopting it for routine tsetse control programs. PMID:25356758

  10. Epidemiology of human African trypanosomiasis

    PubMed Central

    Franco, Jose R; Simarro, Pere P; Diarra, Abdoulaye; Jannin, Jean G

    2014-01-01

    Human African trypanosomiasis (HAT), or sleeping sickness, is caused by Trypanosoma brucei gambiense, which is a chronic form of the disease present in western and central Africa, and by Trypanosoma brucei rhodesiense, which is an acute disease located in eastern and southern Africa. The rhodesiense form is a zoonosis, with the occasional infection of humans, but in the gambiense form, the human being is regarded as the main reservoir that plays a key role in the transmission cycle of the disease. The gambiense form currently assumes that 98% of the cases are declared; the Democratic Republic of the Congo is the most affected country, with more than 75% of the gambiense cases declared. The epidemiology of the disease is mediated by the interaction of the parasite (trypanosome) with the vectors (tsetse flies), as well as with the human and animal hosts within a particular environment. Related to these interactions, the disease is confined in spatially limited areas called “foci”, which are located in Sub-Saharan Africa, mainly in remote rural areas. The risk of contracting HAT is, therefore, determined by the possibility of contact of a human being with an infected tsetse fly. Epidemics of HAT were described at the beginning of the 20th century; intensive activities have been set up to confront the disease, and it was under control in the 1960s, with fewer than 5,000 cases reported in the whole continent. The disease resurged at the end of the 1990s, but renewed efforts from endemic countries, cooperation agencies, and nongovernmental organizations led by the World Health Organization succeeded to raise awareness and resources, while reinforcing national programs, reversing the trend of the cases reported, and bringing the disease under control again. In this context, sustainable elimination of the gambiense HAT, defined as the interruption of the transmission of the disease, was considered as a feasible target for 2030. Since rhodesiense HAT is a zoonosis, where the animal reservoir plays a key role, the interruption of the disease’s transmission is not deemed feasible. PMID:25125985

  11. Control of malaria and other vector-borne protozoan diseases in the tropics: enduring challenges despite considerable progress and achievements

    PubMed Central

    2014-01-01

    Vector-borne protozoan diseases represent a serious public health challenge, especially in the tropics where poverty together with vector-favorable climates are the aggravating factors. Each of the various strategies currently employed to face these scourges is seriously inadequate. Despite enormous efforts, vaccines—which represent the ideal weapon against these parasitic diseases—are yet to be sufficiently developed and implemented. Chemotherapy and vector control are therefore the sole effective attempts to minimize the disease burden. Nowadays, both strategies are also highly challenged by the phenomenon of drug and insecticide resistance, which affects virtually all interventions currently used. The recently growing support from international organizations and governments of some endemic countries is warmly welcome, and should be optimally exploited in the various approaches to drug and insecticide research and development to overcome the burden of these prevalent diseases, especially malaria, leishmaniasis, Human African Trypanosomiasis (HAT), and Chagas disease. PMID:24401663

  12. Parameter estimation of vector controlled induction machine 

    E-print Network

    Rahman, Tahmid Ur

    2002-01-01

    This thesis deals with the modeling and control of induction machine under indirect vector control with parameter estimation in order to get better field oriented performance. Because of its excellent decoupled control, wide flux weakening region...

  13. The effects of trypanosomiasis on rural economy*

    PubMed Central

    Wilson, S. G.; Morris, K. R. S.; Lewis, I. J.; Krog, E.

    1963-01-01

    Trypanosomiasis, both of humans and of livestock, is one of the most important factors restricting economic development in Africa today. The present paper outlines how this disease is limiting agricultural, veterinary and forestry development in the Sudan, Bechuanaland and West Africa. The present tsetse-fly distribution is reviewed. Glossina palpalis and G. morsitans occur in the south Sudan and G. morsitans in the Ngamiland district of Bechuanaland; G. morsitans, G. palpalis and G. tachinoides are the most important species in West Africa. These tsetse flies have altered the cattle distribution in all three regions and, in addition to causing widespread disease, have created local overstocking problems in the tsetse-free grazing areas, and have enforced nomadism on breeding herds and economic loss in slaughter cattle along the trade cattle routes in West Africa. Human trypanosomiasis is not now such an urgent problem and public health measures have led to its control in all three areas. Increased agricultural development, which can be a successful and economic method of reclaiming land from tsetse flies, must be intensified in all three areas. Forest conservation policy comes into conflict with tsetse control measures only in West Africa. Detailed tsetse-fly surveys and research, on which future plans can be firmly based, are now urgently required. ImagesFIG. 6 PMID:14001093

  14. Chagas Disease (American trypanosomiasis)

    MedlinePLUS

    ... vector is a triatomine bug that carries the parasite Trypanosoma cruzi which causes the disease. Chagas disease ... potentially life-threatening illness caused by the protozoan parasite Trypanosoma cruzi (T. cruzi) . It is found mainly ...

  15. Chagas disease (American trypanosomiasis) in Mexico: an update.

    PubMed

    Carabarin-Lima, Alejandro; González-Vázquez, María Cristina; Rodríguez-Morales, Olivia; Baylón-Pacheco, Lidia; Rosales-Encina, José Luis; Reyes-López, Pedro Antonio; Arce-Fonseca, Minerva

    2013-08-01

    Chagas disease is a parasitic infection caused by the protozoan Trypanosoma cruzi, a flagellated organism that is transmitted mainly to humans through the infected feces of triatomine kissing bugs (vector transmission in endemic areas) or by transfusion of infected blood, donations of infected organ, or transmission from an infected mother to her child at birth. Chagas disease was first described in 1909 by the Brazilian physician Carlos Chagas, and due to the parasite's distribution throughout North, Central and South America, the disease is commonly known as American trypanosomiasis. However, this disease is now present in non-endemic countries such as Canada, the United States of America, and several countries in Europe (principally Spain). Moreover, Chagas disease was recently designated by the World Health Organization as one of the main neglected tropical diseases. The aim of this review is to summarize the research efforts recently described in studies conducted in Mexico on Chagas disease. In this country, there are no existing vector control programs. In addition, there is no consensus on the diagnostic methods for acute and chronic Chagas disease in maternity wards and blood banks, and trypanocidal therapy is not administered to chronic patients. The actual prevalence of the disease is unknown because no official reporting of cases is performed. Therefore, the number of people infected by different routes of transmission (vector, congenital, blood transfusion, organ transplantation, or oral) is unknown. We believe that by promoting education about Chagas disease in schools starting at the basic elementary level and including reinforcement at higher education levels will ensure that the Mexican population would be aware of this health problem and that the control measures adopted will have more acceptance and success. We hope that this review sensitizes the relevant authorities and that the appropriate measures to reduce the risk of infection by T. cruzi are undertaken to provide the Mexican people a better quality of life. PMID:23643518

  16. Vector control activities. Fiscal year, 1982

    SciTech Connect

    Pickard, E.; Cooney, J.C.; McDuff, B.R.

    1983-06-01

    The goal of the TVA Vector Control Program is to protect the public from potential vectors of disease by controlling medically-important arthropod pests that are propagated on TVA lands or waters. In addition, freedom from annoying mosquitoes and other blood-sucking pests permits the development, use, and full enjoyment of the vast recreational opportunities offered by the many miles of freshwater lakes. To attain this goal the program is divided into operations and support studies. The support studies are designed to improve the operational effectiveness and efficiency of the control program and to identify other vector control problems that require TVA attention and study. Specifically, activities concerning water level management of TVA lakes, dewatering projects, plant growth control, drainage and insect control programs are detailed. Further, report is made of post-impoundment surveys, soil sampling studies of Mosquite larvae and ecological mosquito management studies.

  17. Integrated vector management for malaria control.

    PubMed

    Beier, John C; Keating, Joseph; Githure, John I; Macdonald, Michael B; Impoinvil, Daniel E; Novak, Robert J

    2008-01-01

    Integrated vector management (IVM) is defined as "a rational decision-making process for the optimal use of resources for vector control" and includes five key elements: 1) evidence-based decision-making, 2) integrated approaches 3), collaboration within the health sector and with other sectors, 4) advocacy, social mobilization, and legislation, and 5) capacity-building. In 2004, the WHO adopted IVM globally for the control of all vector-borne diseases. Important recent progress has been made in developing and promoting IVM for national malaria control programmes in Africa at a time when successful malaria control programmes are scaling-up with insecticide-treated nets (ITN) and/or indoor residual spraying (IRS) coverage. While interventions using only ITNs and/or IRS successfully reduce transmission intensity and the burden of malaria in many situations, it is not clear if these interventions alone will achieve those critical low levels that result in malaria elimination. Despite the successful employment of comprehensive integrated malaria control programmes, further strengthening of vector control components through IVM is relevant, especially during the "end-game" where control is successful and further efforts are required to go from low transmission situations to sustained local and country-wide malaria elimination. To meet this need and to ensure sustainability of control efforts, malaria control programmes should strengthen their capacity to use data for decision-making with respect to evaluation of current vector control programmes, employment of additional vector control tools in conjunction with ITN/IRS tactics, case-detection and treatment strategies, and determine how much and what types of vector control and interdisciplinary input are required to achieve malaria elimination. Similarly, on a global scale, there is a need for continued research to identify and evaluate new tools for vector control that can be integrated with existing biomedical strategies within national malaria control programmes. This review provides an overview of how IVM programmes are being implemented, and provides recommendations for further development of IVM to meet the goals of national malaria control programmes in Africa. PMID:19091038

  18. CONTRIBUTIONS OF INVERTEBRATE PATHOLOGY TO VECTOR CONTROL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Control of the invertebrate host is an integral part of any integrated program to prevent the spread of vector borne diseases of man and animals. This includes important mosquito borne arboviruses such as yellow fever, dengue and the various types of encephalitis including West Nile Virus, St. Loui...

  19. Molecular evidence of a Trypanosoma brucei gambiense sylvatic cycle in the human african trypanosomiasis foci of Equatorial Guinea

    PubMed Central

    Cordon-Obras, Carlos; Rodriguez, Yasmin Fermin; Fernandez-Martinez, Amalia; Cano, Jorge; Ndong-Mabale, Nicolas; Ncogo-Ada, Policarpo; Ndongo-Asumu, Pedro; Aparicio, Pilar; Navarro, Miguel; Benito, Agustin; Bart, Jean-Mathieu

    2015-01-01

    Gambiense trypanosomiasis is considered an anthroponotic disease. Consequently, control programs are generally aimed at stopping transmission of Trypanosoma brucei gambiense (T. b. gambiense) by detecting and treating human cases. However, the persistence of numerous foci despite efforts to eliminate this disease questions this strategy as unique tool to pursue the eradication. The role of animals as a reservoir of T. b. gambiense is still controversial, but could partly explain maintenance of the infection at hypo-endemic levels. In the present study, we evaluated the presence of T. b. gambiense in wild animals in Equatorial Guinea. The infection rate ranged from 0.8% in the insular focus of Luba to more than 12% in Mbini, a focus with a constant trickle of human cases. The parasite was detected in a wide range of animal species including four species never described previously as putative reservoirs. Our study comes to reinforce the hypothesis that animals may play a role in the persistence of T. b. gambiense transmission, being particularly relevant in low transmission settings. Under these conditions the integration of sustained vector control and medical interventions should be considered to achieve the elimination of gambiense trypanosomiasis. PMID:26257727

  20. Thrust vector control using electric actuation

    NASA Astrophysics Data System (ADS)

    Bechtel, Robert T.; Hall, David K.

    1995-01-01

    Presently, gimbaling of launch vehicle engines for thrust vector control is generally accomplished using a hydraulic system. In the case of the space shuttle solid rocket boosters and main engines, these systems are powered by hydrazine auxiliary power units. Use of electromechanical actuators would provide significant advantages in cost and maintenance. However, present energy source technologies such as batteries are heavy to the point of causing significant weight penalties. Utilizing capacitor technology developed by the Auburn University Space Power Institute in collaboration with the Auburn CCDS, Marshall Space Flight Center (MSFC) and Auburn are developing EMA system components with emphasis on high discharge rate energy sources compatible with space shuttle type thrust vector control requirements. Testing has been done at MSFC as part of EMA system tests with loads up to 66000 newtons for pulse times of several seconds. Results show such an approach to be feasible providing a potential for reduced weight and operations costs for new launch vehicles.

  1. Flexible joints for thrust vector control

    NASA Technical Reports Server (NTRS)

    Woodberry, R. F. H.

    1975-01-01

    Flexible joints have been used to achieve thrust vector control over a wide range of sizes of nozzles and have been demonstrated successfully in bench tests and static firings, and are operational on two motors. From these many joints the problems of flexible joints have been defined as establishment of the movable nozzle envelope, definition of the actuation power requirements, definition of the mechanical properties of joint materials, adhesive bonding, test methods, and quality control. These data and problem solutions are contained in a large number of reports. Data relating to joint configuration, design requirements, materials selection, joint design, structural analysis, manufacture, and testing are summarized.

  2. 40 CFR 258.22 - Disease vector control.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Disease vector control. 258.22 Section... MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.22 Disease vector control. (a) Owners or operators of all MSWLF units must prevent or control on-site populations of disease vectors using...

  3. 40 CFR 258.22 - Disease vector control.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Disease vector control. 258.22 Section... MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.22 Disease vector control. (a) Owners or operators of all MSWLF units must prevent or control on-site populations of disease vectors using...

  4. 40 CFR 258.22 - Disease vector control.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Disease vector control. 258.22 Section... MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.22 Disease vector control. (a) Owners or operators of all MSWLF units must prevent or control on-site populations of disease vectors using...

  5. 40 CFR 258.22 - Disease vector control.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Disease vector control. 258.22 Section... MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.22 Disease vector control. (a) Owners or operators of all MSWLF units must prevent or control on-site populations of disease vectors using...

  6. 40 CFR 258.22 - Disease vector control.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Disease vector control. 258.22 Section... MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.22 Disease vector control. (a) Owners or operators of all MSWLF units must prevent or control on-site populations of disease vectors using...

  7. 40 CFR 258.22 - Disease vector control.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Disease vector control. 258.22 Section...LANDFILLS Operating Criteria § 258.22 Disease vector control. (a) Owners or operators...prevent or control on-site populations of disease vectors using techniques...

  8. 40 CFR 258.22 - Disease vector control.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Disease vector control. 258.22 Section...LANDFILLS Operating Criteria § 258.22 Disease vector control. (a) Owners or operators...prevent or control on-site populations of disease vectors using techniques...

  9. 40 CFR 258.22 - Disease vector control.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Disease vector control. 258.22 Section...LANDFILLS Operating Criteria § 258.22 Disease vector control. (a) Owners or operators...prevent or control on-site populations of disease vectors using techniques...

  10. 40 CFR 258.22 - Disease vector control.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Disease vector control. 258.22 Section...LANDFILLS Operating Criteria § 258.22 Disease vector control. (a) Owners or operators...prevent or control on-site populations of disease vectors using techniques...

  11. 40 CFR 258.22 - Disease vector control.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2011-07-01 true Disease vector control. 258.22 Section...LANDFILLS Operating Criteria § 258.22 Disease vector control. (a) Owners or operators...prevent or control on-site populations of disease vectors using techniques...

  12. Vector and reservoir control for preventing leishmaniasis

    PubMed Central

    González, Urbà; Pinart, Mariona; Sinclair, David; Firooz, Alireza; Enk, Claes; Vélez, Ivan D; Esterhuizen, Tonya M; Tristan, Mario; Alvar, Jorge

    2015-01-01

    Background Leishmaniasis is caused by the Leishmania parasite, and transmitted by infected phlebotomine sandflies. Of the two distinct clinical syndromes, cutaneous leishmaniasis (CL) affects the skin and mucous membranes, and visceral leishmaniasis (VL) affects internal organs. Approaches to prevent transmission include vector control by reducing human contact with infected sandflies, and reservoir control, by reducing the number of infected animals. Objectives To assess the effects of vector and reservoir control interventions for cutaneous and for visceral leishmaniasis. Search methods We searched the following databases to 13 January 2015: Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, EMBASE, LILACS and WHOLIS, Web of Science, and RePORTER. We also searched trials registers for ongoing trials. Selection criteria Randomized controlled trials (RCTs) evaluating the effects of vector and reservoir control interventions in leishmaniasis-endemic regions. Data collection and analysis Two review authors independently searched for trials and extracted data from included RCTs. We resolved any disagreements by discussion with a third review author. We assessed the quality of the evidence using the GRADE approach. Main results We included 14 RCTs that evaluated a range of interventions across different settings. The study methods were generally poorly described, and consequently all included trials were judged to be at high or unclear risk of selection and reporting bias. Only seven trials reported clinical outcome data which limits our ability to make broad generalizations to different epidemiological settings and cultures. Cutaneous leishmaniasis One four-arm RCT from Afghanistan compared indoor residual spraying (IRS), insecticide-treated bednets (ITNs), and insecticide-treated bedsheets, with no intervention. Over 15 months follow-up, all three insecticide-based interventions had a lower incidence of CL than the control area (IRS: risk ratio (RR) 0.61, 95% confidence interval (CI) 0.38 to 0.97, 2892 participants, moderate quality evidence; ITNs: RR 0.32, 95% CI 0.18 to 0.56, 2954 participants, low quality evidence; ITS: RR 0.34, 95% CI 0.20 to 0.57, 2784 participants, low quality evidence). No difference was detected between the three interventions (low quality evidence). One additional trial of ITNs from Iran was underpowered to show a difference. Insecticide treated curtains were compared with no intervention in one RCT from Venezuela, where there were no CL episodes in the intervention areas over 12 months follow-up compared to 142 in control areas (RR 0.00, 95% CI 0.00 to 0.49, one trial, 2938 participants, low quality evidence). Personal protection using insecticide treated clothing was evaluated by two RCTs in soldiers, but the trials were underpowered to reliably detect effects on the incidence of CL (RR 0.40, 95% CI 0.13 to 1.20, two trials, 558 participants, low quality evidence). Visceral leishmaniasis In a single RCT of ITNs versus no intervention from India and Nepal, the incidence of VL was low in both groups and no difference was detected (RR 0.99, 95% CI 0.46 to 2.15, one trial, 19,810 participants, moderate quality evidence). Two trials from Brazil evaluated the effects of culling infected dogs compared to no intervention or IRS. Although they report a reduction in seroconversion over 18 months follow-up, they did not measure or report effects on clinical disease. Authors' conclusions Using insecticides to reduce phlebotomine sandfly numbers may be effective at reducing the incidence of CL, but there is insufficient evidence from trials to know whether it is better to spray the internal walls of houses or to treat bednets, curtains, bedsheets or clothing. PLAIN LANGUAGE SUMMARY Vector and reservoir control for preventing leishmaniasis This review summarises trials evaluating different measures to prevent leishmaniasis. After searching for relevant trials up to January 2015, we included 14 randomized controlled trials. What is vector and reservoir control and how might they prevent

  13. Preventing the transmission of American trypanosomiasis and its spread into non-endemic countries.

    PubMed

    Liu, Qin; Zhou, Xiao-Nong

    2015-01-01

    American trypanosomiasis, commonly known as Chagas disease, is caused by the flagellate protozoan parasite Trypanosoma cruzi. An estimated eight million people infected with T. cruzi currently reside in the endemic regions of Latin America. However, as the disease has now been imported into many non-endemic countries outside of Latin America, it has become a global health issue. We reviewed the transmission patterns and current status of disease spread pertaining to American trypanosomiasis at the global level, as well as recent advances in research. Based on an analysis of the gaps in American trypanosomiasis control, we put forward future research priorities that must be implemented to stop the global spread of the disease. PMID:26715535

  14. Electromechanical actuation for thrust vector control applications

    NASA Technical Reports Server (NTRS)

    Roth, Mary Ellen

    1990-01-01

    At present, actuation systems for the Thrust Vector Control (TVC) for launch vehicles are hydraulic systems. The Advanced Launch System (ALS), a joint initiative between NASA and the Air Force, is a launch vehicle that is designed to be cost effective, highly reliable and operationally efficient with a goal of reducing the cost per pound to orbit. As part of this initiative, an electromechanical actuation system is being developed as an attractive alternative to the hydraulic systems used today. NASA-Lewis is developing and demonstrating an Induction Motor Controller Actuation System with a 40 hp peak rating. The controller will integrate 20 kHz resonant link Power Management and Distribution (PMAD) technology and Pulse Population Modulation (PPM) techniques to implement Field Oriented Vector Control (FOVC) of a new advanced induction motor. Through PPM, multiphase variable frequency, variable voltage waveforms can be synthesized from the 20 kHz source. FOVC shows that varying both the voltage and frequency and their ratio (V/F), permits independent control of both torque and speed while operating at maximum efficiency at any point on the torque-speed curve. The driver and the FOVC will be microprocessor controlled. For increased system reliability, a Built-in Test (BITE) capability will be included. This involves introducing testability into the design of a system such that testing is calibrated and exercised during the design, manufacturing, maintenance and prelaunch activities. An actuator will be integrated with the motor controller for performance testing of the EMA TVC system. The design and fabrication of the motor controller is being done by General Dynamics Space Systems Division. The University of Wisconsin-Madison will assist in the design of the advanced induction motor and in the implementation of the FOVC theory. A 75 hp electronically controlled dynamometer will be used to test the motor controller in all four quadrants of operation using flight type control algorithms. Integrated testing of the controller and actuator will be conducted at a facility yet to be named. The EMA system described above is discussed in detail.

  15. Using Cell Phones for Mosquito Vector Surveillance and Control

    E-print Network

    Bieman, James M.

    Using Cell Phones for Mosquito Vector Surveillance and Control S. Lozano-Fuentes, S. Ghosh, J. M--Novel, low-cost approaches to improving prevention and control of vector-borne diseases, such as mosquito the use of cell phones for field capture and rapid transfer of mosquito vector surveillance data

  16. Thrust vector control using electric actuation

    SciTech Connect

    Bechtel, R.T.; Hall, D.K.

    1995-01-25

    Presently, gimbaling of launch vehicle engines for thrust vector control is generally accomplished using a hydraulic system. In the case of the space shuttle solid rocket boosters and main engines, these systems are powered by hydrazine auxiliary power units. Use of electromechanical actuators would provide significant advantages in cost and maintenance. However, present energy source technologies such as batteries are heavy to the point of causing significant weight penalties. Utilizing capacitor technology developed by the Auburn University Space Power Institute in collaboration with the Auburn CCDS, Marshall Space Flight Center (MSFC) and Auburn are developing EMA system components with emphasis on high discharge rate energy sources compatible with space shuttle type thrust vector control requirements. Testing has been done at MSFC as part of EMA system tests with loads up to 66000 newtons for pulse times of several seconds. Results show such an approach to be feasible providing a potential for reduced weight and operations costs for new launch vehicles. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}

  17. A longitudinal survey of African animal trypanosomiasis in domestic cattle on the Jos Plateau, Nigeria: prevalence, distribution and risk factors

    PubMed Central

    2013-01-01

    Background Trypanosomiasis is a widespread disease of livestock in Nigeria and a major constraint to the rural economy. The Jos Plateau, Nigeria was free from tsetse flies and the trypanosomes they transmit due to its high altitude and the absence of animal trypanosomiasis attracted large numbers of cattle-keeping pastoralists to inhabit the plateau. The Jos Plateau now plays a significant role in the national cattle industry, accommodating approximately 7% of the national herd and supporting 300,000 pastoralists and over one million cattle. However, during the past two decades tsetse flies have invaded the Jos Plateau and animal trypanosomiasis has become a significant problem for livestock keepers. Methods In 2008 a longitudinal two-stage cluster survey on the Jos Plateau. Cattle were sampled in the dry, early wet and late wet seasons. Parasite identification was undertaken using species-specific polymerase chain reactions to determine the prevalence and distribution bovine trypanosomiasis. Logistic regression was performed to determine risk factors for disease. Results The prevalence of bovine trypanosomiasis (Trypanosoma brucei brucei, Trypanosoma congolense savannah, Trypanosoma vivax) across the Jos Plateau was found to be high at 46.8% (39.0 – 54.5%) and significant, seasonal variation was observed between the dry season and the end of the wet season. T. b. brucei was observed at a prevalence of 3.2% (1% – 5.5%); T. congolense at 27.7% (21.8% - 33.6%) and T. vivax at 26.7% (18.2% - 35.3%). High individual variation was observed in trypanosomiasis prevalence between individual villages on the Plateau, ranging from 8.8% to 95.6%. Altitude was found to be a significant risk factor for trypanosomiasis whilst migration also influenced risk for animal trypanosomiasis. Conclusions Trypanosomiasis is now endemic on the Jos Plateau showing high prevalence in cattle and is influenced by seasonality, altitude and migration practices. Attempts to successfully control animal trypanosomiasis on the Plateau will need to take into account the large variability in trypanosomiasis infection rates between villages, the influence of land use, and husbandry and management practices of the pastoralists, all of which affect the epidemiology of the disease. PMID:23958205

  18. Speed sensorless hybrid vector controlled induction motor drive

    SciTech Connect

    Bose, B.K.; Simoes, M.G.; Crecelius, D.R.; Rajashekara, K.; Martin, R.

    1995-12-31

    The paper describes a speed and flux sensorless vector-controlled induction motor drive primarily aimed for electric vehicle type applications. The stator flux oriented drive starts at zero speed in indirect vector control mode, transitions to direct vector control mode as the speed develops, and then transitions back to indirect vector control at zero speed. The vector control uses stator flux orientation in both indirect and direct vector control modes with the stator resistance variation compensated by measurement of stator temperature. The problem of integration at low stator frequency is solved by cascaded low pass filters with programmable time constants. The control strategy of the four-quadrant drive has been analyzed, validated by simulation study, and finally evaluated by experimental study on a laboratory 5 hp drive system.

  19. Some principles of the immunology of trypanosomiasis

    PubMed Central

    Gray, A. R.

    1967-01-01

    Although immunological methods have not been used on a wide scale for the study of trypanosomiasis in Africa, there is hope that immunological research will lead to improved methods of diagnosis, methods for the classification of trypanosome strains, better understanding of the epidemiology, epizootiology and pathology of trypanosomiasis, and ultimately the development of methods of immunization against the disease. This paper reviews some of the problems that hinder progress in each of these areas. Such problems include inadequacies in existing methods of obtaining antigens of Trypanosoma vivax, T. congolense, and T. gambiense; the general lack of fundamental information on the nature and properties of trypanosome antigens; and the variability of certain trypanosome antigens in infected animals. Recent progress towards the solution of these problems is summarized, and aspects of the immunology of trypanosomiasis that require further study are discussed. These include the diagnostic value of determinations of IgM globulin levels; the properties of T. vivax and T. congolense antigens; the natural immunity of game animals and certain varieties of cattle to trypanosomiasis; and the possibility of immunizing livestock by exposing drug-treated animals to a continuous low-grade trypanosome challenge. PMID:4866448

  20. Thrust Vector Control for Nuclear Thermal Rockets

    NASA Technical Reports Server (NTRS)

    Ensworth, Clinton B. F.

    2013-01-01

    Future space missions may use Nuclear Thermal Rocket (NTR) stages for human and cargo missions to Mars and other destinations. The vehicles are likely to require engine thrust vector control (TVC) to maintain desired flight trajectories. This paper explores requirements and concepts for TVC systems for representative NTR missions. Requirements for TVC systems were derived using 6 degree-of-freedom models of NTR vehicles. Various flight scenarios were evaluated to determine vehicle attitude control needs and to determine the applicability of TVC. Outputs from the models yielded key characteristics including engine gimbal angles, gimbal rates and gimbal actuator power. Additional factors such as engine thrust variability and engine thrust alignment errors were examined for impacts to gimbal requirements. Various technologies are surveyed for TVC systems for the NTR applications. A key factor in technology selection is the unique radiation environment present in NTR stages. Other considerations including mission duration and thermal environments influence the selection of optimal TVC technologies. Candidate technologies are compared to see which technologies, or combinations of technologies best fit the requirements for selected NTR missions. Representative TVC systems are proposed and key properties such as mass and power requirements are defined. The outputs from this effort can be used to refine NTR system sizing models, providing higher fidelity definition for TVC systems for future studies.

  1. Towards the Atlas of human African trypanosomiasis

    PubMed Central

    Cecchi, Giuliano; Paone, Massimo; Franco, José R; Fèvre, Eric M; Diarra, Abdoulaye; Ruiz, José A; Mattioli, Raffaele C; Simarro, Pere P

    2009-01-01

    Background Updated, accurate and comprehensive information on the distribution of human African trypanosomiasis (HAT), also known as sleeping sickness, is critically important to plan and monitor control activities. We describe input data, methodology, preliminary results and future prospects of the HAT Atlas initiative, which will allow major improvements in the understanding of the spatial distribution of the disease. Methods Up-to-date as well as historical data collected by national sleeping sickness control programmes, non-governmental organizations and research institutes have been collated over many years by the HAT Control and Surveillance Programme of the World Health Organization. This body of information, unpublished for the most part, is now being screened, harmonized, and analysed by means of database management systems and geographical information systems (GIS). The number of new HAT cases and the number of people screened within a defined geographical entity were chosen as the key variables to map disease distribution in sub-Saharan Africa. Results At the time of writing, over 600 epidemiological reports and files from seventeen countries were collated and included in the data repository. The reports contain information on approximately 20,000 HAT cases, associated to over 7,000 different geographical entities. The oldest epidemiological records considered so far date back to 1985, the most recent having been gathered in 2008. Data from Cameroon, Central African Republic, Chad, Congo, Equatorial Guinea and Gabon from the year 2000 onwards were fully processed and the preliminary regional map of HAT distribution is presented. Conclusion The use of GIS tools and geo-referenced, village-level epidemiological data allow the production of maps that substantially improve on the spatial quality of previous cartographic products of similar scope. The significant differences between our preliminary outputs and earlier maps of HAT transmission areas demonstrate the strong need for this systematic approach to mapping sleeping sickness and point to the inaccuracy of any calculation of population at risk based on previous maps of HAT transmission areas. The Atlas of HAT will lay the basis for novel, evidence-based methodologies to estimate the population at risk and the burden of disease, ultimately leading to more efficient targeting of interventions. Also, the Atlas will help streamline future field data collection in those parts of Africa that still require it. PMID:19296837

  2. Exploiting the potential of vector control for disease prevention.

    PubMed Central

    Townson, H.; Nathan, M. B.; Zaim, M.; Guillet, P.; Manga, L.; Bos, R.; Kindhauser, M.

    2005-01-01

    Although vector control has proven highly effective in preventing disease transmission, it is not being used to its full potential, thereby depriving disadvantaged populations of the benefits of well tried and tested methods. Following the discovery of synthetic residual insecticides in the 1940s, large-scale programmes succeeded in bringing many of the important vector-borne diseases under control. By the late 1960s, most vector-borne diseases--with the exception of malaria in Africa--were no longer considered to be of primary public health importance. The result was that control programmes lapsed, resources dwindled, and specialists in vector control disappeared from public health units. Within two decades, many important vector-borne diseases had re-emerged or spread to new areas. The time has come to restore vector control to its key role in the prevention of disease transmission, albeit with an increased emphasis on multiple measures, whether pesticide-based or involving environmental modification, and with a strengthened managerial and operational capacity. Integrated vector management provides a sound conceptual framework for deployment of cost-effective and sustainable methods of vector control. This approach allows for full consideration of the complex determinants of disease transmission, including local disease ecology, the role of human activity in increasing risks of disease transmission, and the socioeconomic conditions of affected communities. PMID:16462987

  3. Social factors affecting seasonal variation in bovine trypanosomiasis on the Jos Plateau, Nigeria

    PubMed Central

    2013-01-01

    Background African Animal Trypanosomiasis (AAT) is a widespread disease of livestock in Nigeria and presents a major constraint to rural economic development. The Jos Plateau was considered free from tsetse flies and the trypanosomes they transmit due to its high altitude and this trypanosomiasis free status attracted large numbers of cattle-keeping pastoralists to the area. The Jos Plateau now plays a major role in the national cattle industry in Nigeria, accommodating approximately 7% of the national herd, supporting 300,000 pastoralists and over one million cattle. During the past two decades tsetse flies have invaded the Jos Plateau and animal trypanosomiasis has become a significant problem for livestock keepers. Here we investigate the epidemiology of trypanosomiasis as a re-emerging disease on the Plateau, examining the social factors that influence prevalence and seasonal variation of bovine trypanosomiasis. Methods In 2008 a longitudinal two-stage cluster survey was undertaken on the Jos Plateau. Cattle were sampled in the dry, early wet and late wet seasons. Parasite identification was undertaken using species-specific polymerase chain reactions to determine the prevalence and distribution of bovine trypanosomiasis. Participatory rural appraisal was also conducted to determine knowledge, attitudes and practices concerning animal husbandry and disease control. Results Significant seasonal variation between the dry season and late wet season was recorded across the Jos Plateau, consistent with expected variation in tsetse populations. However, marked seasonal variations were also observed at village level to create 3 distinct groups: Group 1 in which 50% of villages followed the general pattern of low prevalence in the dry season and high prevalence in the wet season; Group 2 in which 16.7% of villages showed no seasonal variation and Group 3 in which 33.3% of villages showed greater disease prevalence in the dry season than in the wet season. Conclusions There was high seasonal variation at the village level determined by management as well as climatic factors. The growing influence of management factors on the epidemiology of trypanosomiasis highlights the impact of recent changes in land use and natural resource competition on animal husbandry decisions in the extensive pastoral production system. PMID:24172046

  4. Is Vector Control Sufficient to Limit Pathogen Spread in Vineyards?

    PubMed

    Daugherty, M P; O'Neill, S; Byrne, F; Zeilinger, A

    2015-06-01

    Vector control is widely viewed as an integral part of disease management. Yet epidemiological theory suggests that the effectiveness of control programs at limiting pathogen spread depends on a variety of intrinsic and extrinsic aspects of a pathosystem. Moreover, control programs rarely evaluate whether reductions in vector density or activity translate into reduced disease prevalence. In areas of California invaded by the glassy-winged sharpshooter (Homalodisca vitripennis Germar), Pierce's disease management relies heavily on chemical control of this vector, primarily via systemic conventional insecticides (i.e., imidacloprid). But, data are lacking that attribute reduced vector pressure and pathogen spread to sharpshooter control. We surveyed 34 vineyards over successive years to assess the epidemiological value of within-vineyard chemical control. The results showed that imidacloprid reduced vector pressure without clear nontarget effects or secondary pest outbreaks. Effects on disease prevalence were more nuanced. Treatment history over the preceding 5?yr affected disease prevalence, with significantly more diseased vines in untreated compared with regularly or intermittently treated vineyards. Yet, the change in disease prevalence between years was low, with no significant effects of insecticide treatment or vector abundance. Collectively, the results suggest that within-vineyard applications of imidacloprid can reduce pathogen spread, but with benefits that may take multiple seasons to become apparent. The relatively modest effect of vector control on disease prevalence in this system may be attributable in part to the currently low regional sharpshooter population densities stemming from area-wide control, without which the need for within-vineyard vector control would be more pronounced. PMID:26313985

  5. Trypanosomiasis re-emerges under cover of war.

    PubMed

    1997-09-01

    The incidence of trypanosomiasis has increased in southern Sudan along the border of the Central African Republic; up to 30% of the population is infected in some areas. A study conducted by CARE and the US Centers for Disease Control (CDC) has shown that the disease has spread to over 30,000 people in Tambura county alone; up to 4% of the local population is expected to die this year. According to the local coordinator for CARE, the pyramidal effect is great; when a tsetse fly bites a human, he or she becomes a host who is bitten by uninfected flies that then become carriers to other humans. The disease spreads exponentially. A tsetse fly can bite 3-4 humans/day, and there are thousands of flies in the area. A member of the CDC research team warns that the problem is regional; the annual incidence of the disease in the former Zaire is higher than at any time in the last 60 years, and the mortality associated with the disease is approaching that of AIDS. In a Ugandan outbreak in 1906, 4 million people died; at the turn of the century, trypanosomiasis was the greatest health threat in the tropics, greater even than malaria. Although tsetse fly control gradually reduced the incidence of the disease to less than 1% in the early 1980s, war and population displacement overturned these gains. CARE's director in southern Sudan warns that war and civil conflict are contributing to the reemergence of "super" diseases like sleeping sickness. The assessment team had to cease activities halfway through July 1997, when rebel soldiers commandeered the team's vehicles. PMID:12321240

  6. American trypanosomiasis (Chagas' disease) in the Caribbean.

    PubMed

    Petana, W B

    1978-01-01

    Chagas' disease (American trypanosomiasis) is endemic in nearly all Central and South American countries facing the Caribbean basin. Since 1960, reports from the islands of Aruba, Curaçao, Jamaica, and Trinidad have confirmed the presence of Trypanosoma cruzi, blood-sucking triatomine bugs, and wild animals infected with the parasite. It was also established that T. cruzi, triatomine bugs, infected wild animal reservoirs, and people with a positive serologic test for T. cruzi antibodies are to be found in Belize, the last country in Central America once thought to be free of Chagas' disease. PMID:96895

  7. A Literature Review of Economic Evaluations for a Neglected Tropical Disease: Human African Trypanosomiasis (“Sleeping Sickness”)

    PubMed Central

    Sutherland, C. Simone; Yukich, Joshua; Goeree, Ron; Tediosi, Fabrizio

    2015-01-01

    Human African trypanosomiasis (HAT) is a disease caused by infection with the parasite Trypanosoma brucei gambiense or T. b. rhodesiense. It is transmitted to humans via the tsetse fly. Approximately 70 million people worldwide were at risk of infection in 1995, and approximately 20,000 people across Africa are infected with HAT. The objective of this review was to identify existing economic evaluations in order to summarise cost-effective interventions to reduce, control, or eliminate the burden of HAT. The studies included in the review were compared and critically appraised in order to determine if there were existing standardised methods that could be used for economic evaluation of HAT interventions or if innovative methodological approaches are warranted. A search strategy was developed using keywords and was implemented in January 2014 in several databases. The search returned a total of 2,283 articles. After two levels of screening, a total of seven economic evaluations were included and underwent critical appraisal using the Scottish Intercollegiate Guidelines Network (SIGN) Methodology Checklist 6: Economic Evaluations. Results from the existing studies focused on the cost-effectiveness of interventions for the control and reduction of disease transmission. Modelling was a common method to forecast long-term results, and publications focused on interventions by category, such as case detection, diagnostics, drug treatments, and vector control. Most interventions were considered cost-effective based on the thresholds described; however, the current treatment, nifurtomix-eflornithine combination therapy (NECT), has not been evaluated for cost-effectiveness, and considerations for cost-effective strategies for elimination have yet to be completed. Overall, the current evidence highlights the main components that play a role in control; however, economic evaluations of HAT elimination strategies are needed to assist national decision makers, stakeholders, and key funders. These analyses would be of use, as HAT is currently being prioritized as a neglected tropical disease (NTD) to reach elimination by 2020. PMID:25654605

  8. Genetically Distinct Glossina fuscipes fuscipes Populations in the Lake Kyoga Region of Uganda and Its Relevance for Human African Trypanosomiasis

    PubMed Central

    Echodu, Richard; Sistrom, Mark; Hyseni, Chaz; Enyaru, John; Okedi, Loyce; Aksoy, Serap; Caccone, Adalgisa

    2013-01-01

    Tsetse flies (Glossina spp.) are the sole vectors of Trypanosoma brucei—the agent of human (HAT) and animal (AAT) trypanosomiasis. Glossina fuscipes fuscipes (Gff) is the main vector species in Uganda—the only country where the two forms of HAT disease (rhodesiense and gambiense) occur, with gambiense limited to the northwest. Gff populations cluster in three genetically distinct groups in northern, southern, and western Uganda, respectively, with a contact zone present in central Uganda. Understanding the dynamics of this contact zone is epidemiologically important as the merger of the two diseases is a major health concern. We used mitochondrial and microsatellite DNA data from Gff samples in the contact zone to understand its spatial extent and temporal stability. We show that this zone is relatively narrow, extending through central Uganda along major rivers with south to north introgression but displaying no sex-biased dispersal. Lack of obvious vicariant barriers suggests that either environmental conditions or reciprocal competitive exclusion could explain the patterns of genetic differentiation observed. Lack of admixture between northern and southern populations may prevent the sympatry of the two forms of HAT disease, although continued control efforts are needed to prevent the recolonization of tsetse-free regions by neighboring populations. PMID:24199195

  9. A role for vector control in dengue vaccine programs.

    PubMed

    Christofferson, Rebecca C; Mores, Christopher N

    2015-12-10

    Development and deployment of a successful dengue virus (DENV) vaccine has confounded research and pharmaceutical entities owing to the complex nature of DENV immunity and concerns over exacerbating the risk of DENV hemorrhagic fever (DHF) as a consequence of vaccination. Thus, consensus is growing that a combination of mitigation strategies will be needed for DENV to be successfully controlled, likely involving some form of vector control to enhance a vaccine program. We present here a deterministic compartmental model to illustrate that vector control may enhance vaccination campaigns with imperfect coverage and efficacy. Though we recognize the costs and challenges associated with continuous control programs, simultaneous application of vector control methods coincident with vaccine roll out can have a positive effect by further reducing the number of human cases. The success of such an integrative strategy is predicated on closing gaps in our understanding of the DENV transmission cycle in hyperedemic locations. PMID:26478199

  10. Sleeping sickness: perspectives in African trypanosomiasis.

    PubMed

    Mhlanga, J D

    1996-01-01

    African trypanosomiasis has recently been relegated in the league table of the major infectious diseases. However, in the light of the serious instability of most countries on the African continent, due to civil unrest, political turmoil and unabated fratricidal wars, mass movements of refugees across national borders, to and from sleeping sickness foci, the resurgence and spread of this disease is on the increase. These movements of people en masse are analogous to those which, at the turn of the century led to outbreaks of sleeping sickness killing thousands of people in areas which had previously not experienced this disease. The present situation is compounded by severe budgetary constraints and lack of human resources, making it virtually impossible to undertake surveillance programmes and to deliver health services to already destabilished populations. Current molecular and biochemical studies on the African trypanosome suggest a need for reappraisal of strategies for the diagnosis and treatment of both the chronic and acute forms of sleeping sickness. These studies have also highlighted the complexity of animal trypanosomiasis (nagana). There is an urgent need to understand first, fundamental elements of protection by the immune system, especially in the light of recent findings on the interaction(s), at the outset, between T-cell subsets, B cells, cytokines and parasites and/or parasite derived components (trypanokines), and second, the mechanisms of action of the drugs currently used. PMID:8973165

  11. Implementation of a new fuzzy vector control of induction motor.

    PubMed

    Rafa, Souad; Larabi, Abdelkader; Barazane, Linda; Manceur, Malik; Essounbouli, Najib; Hamzaoui, Abdelaziz

    2014-05-01

    The aim of this paper is to present a new approach to control an induction motor using type-1 fuzzy logic. The induction motor has a nonlinear model, uncertain and strongly coupled. The vector control technique, which is based on the inverse model of the induction motors, solves the coupling problem. Unfortunately, in practice this is not checked because of model uncertainties. Indeed, the presence of the uncertainties led us to use human expertise such as the fuzzy logic techniques. In order to maintain the decoupling and to overcome the problem of the sensitivity to the parametric variations, the field-oriented control is replaced by a new block control. The simulation results show that the both control schemes provide in their basic configuration, comparable performances regarding the decoupling. However, the fuzzy vector control provides the insensitivity to the parametric variations compared to the classical one. The fuzzy vector control scheme is successfully implemented in real-time using a digital signal processor board dSPACE 1104. The efficiency of this technique is verified as well as experimentally at different dynamic operating conditions such as sudden loads change, parameter variations, speed changes, etc. The fuzzy vector control is found to be a best control for application in an induction motor. PMID:24629620

  12. Robust nonlinear control of vectored thrust aircraft

    NASA Technical Reports Server (NTRS)

    Doyle, John C.; Murray, Richard; Morris, John

    1993-01-01

    An interdisciplinary program in robust control for nonlinear systems with applications to a variety of engineering problems is outlined. Major emphasis will be placed on flight control, with both experimental and analytical studies. This program builds on recent new results in control theory for stability, stabilization, robust stability, robust performance, synthesis, and model reduction in a unified framework using Linear Fractional Transformations (LFT's), Linear Matrix Inequalities (LMI's), and the structured singular value micron. Most of these new advances have been accomplished by the Caltech controls group independently or in collaboration with researchers in other institutions. These recent results offer a new and remarkably unified framework for all aspects of robust control, but what is particularly important for this program is that they also have important implications for system identification and control of nonlinear systems. This combines well with Caltech's expertise in nonlinear control theory, both in geometric methods and methods for systems with constraints and saturations.

  13. Vector Control and Surveillance Operations in the Republic of Singapore

    PubMed Central

    Yoshikawa, Minako Jen

    2013-01-01

    Singapore is known for its comprehensive vector control methods that keep mosquito populations at low levels in the urban, tropical, and green city-state. This report describes the measures taken by the National Environment Agency on the basis of observations of vector control and surveillance activities in residential areas, construction sites, and foreign worker quarters. The government-led active operations dealt not only with mosquito control but also social issues in urban residential buildings where people with varying preferences live, the responsibilities of the business sector, and the education of multi-cultural/lingual residents and foreign workers. The public health measures implemented in Singapore offer useful ideas to countries/cities that have not yet established vector control programs against mosquito-borne infectious diseases. PMID:23874140

  14. Spray characterization of ULV sprayers typically used in vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous spray machines are used to apply products for the control of human disease vectors, such as mosquitoes and flies. However, the selection and setup of these machines significantly affect the level of control achieved during an application. The droplet spectra produced by nine different ULV...

  15. Dengue in Cape Verde: vector control and vaccination

    E-print Network

    Rodrigues, Helena Sofia; Torres, Delfim F M

    2012-01-01

    In 2009, for the first time in Cape Verde, an outbreak of dengue was reported and over twenty thousand people were infected. Only a few prophylactic measures were taken. The effects of vector control on disease spreading, such as insecticide (larvicide and adulticide) and mechanical control, as well as an hypothetical vaccine, are estimated through simulations with the Cape Verde data.

  16. A Quasioptical Vector Interferometer for Polarization Control

    NASA Technical Reports Server (NTRS)

    Chuss, David T.; Wollack, Edward J.; Moseley, Harvey S.; Novak, Giles

    2005-01-01

    We present a mathematical description of a Quasioptical Vector Interferometer (QVI), a device that maps an input polarization state to an output polarization state by introducing a phase delay between two linear orthogonal components of the input polarization. The advantages of such a device over a spinning wave-plate modulator for measuring astronomical polarization in the far-infrared through millimeter are: 1. The use of small, linear motions eliminates the need for cryogenic rotational bearings, 2. The phase flexibility allows measurement of Stokes V as well as Q and U, and 3. The QVI allows for both multi-wavelength and broadband modulation. We suggest two implementations of this device as an astronomical polarization modulator. The first involves two such modulators placed in series. By adjusting the two phase delays, it is possible to use such a modulator to measure Stokes Q, U, and V for passbands that are not too large. Conversely, a single QVI may be used to measure Q and V independent of frequency. In this implementation, Stokes U must be measured by rotating the instrument. We conclude this paper by presenting initial laboratory results.

  17. American Trypanosomiasis (Also Known as Chagas Disease) Diagnosis

    MedlinePLUS

    ... CDC.gov . Parasites - American Trypanosomiasis (also known as Chagas Disease) Parasites Home Share Compartir Diagnosis Trypansoma cruzi parasite ... thin blood smear. (CDC Photo) The diagnosis of Chagas disease can be made by observation of the parasite ...

  18. A Critical Assessment of Vector Control for Dengue Prevention

    PubMed Central

    Achee, Nicole L.; Gould, Fred; Perkins, T. Alex; Reiner, Robert C.; Morrison, Amy C.; Ritchie, Scott A.; Gubler, Duane J.; Teyssou, Remy; Scott, Thomas W.

    2015-01-01

    Recently, the Vaccines to Vaccinate (v2V) initiative was reconfigured into the Partnership for Dengue Control (PDC), a multi-sponsored and independent initiative. This redirection is consistent with the growing consensus among the dengue-prevention community that no single intervention will be sufficient to control dengue disease. The PDC's expectation is that when an effective dengue virus (DENV) vaccine is commercially available, the public health community will continue to rely on vector control because the two strategies complement and enhance one another. Although the concept of integrated intervention for dengue prevention is gaining increasingly broader acceptance, to date, no consensus has been reached regarding the details of how and what combination of approaches can be most effectively implemented to manage disease. To fill that gap, the PDC proposed a three step process: (1) a critical assessment of current vector control tools and those under development, (2) outlining a research agenda for determining, in a definitive way, what existing tools work best, and (3) determining how to combine the best vector control options, which have systematically been defined in this process, with DENV vaccines. To address the first step, the PDC convened a meeting of international experts during November 2013 in Washington, DC, to critically assess existing vector control interventions and tools under development. This report summarizes those deliberations. PMID:25951103

  19. [Chagas disease (American trypanosomiasis) in France].

    PubMed

    Salamanca-Dejour, D; Blanchet, D; Aznar, C; La Ruche, G; Jeannel, D; Gastellu-Etchegorry, M

    2012-08-01

    Chagas disease is an anthropozoonotic infection caused by Trypanosoma cruzi, transmitted by a hematophagous triatomine insect vector belonging to the Reduviidae family, while taking a blood meal. There is a large reservoir of wild and domestic mammals. Human contamination may come via vectorial, transplacental, and digestive routes, blood transfusion, organ or tissue transplantation, and by accident. The disease has two phases. The acute phase, oligosymptomatic, is frequently undiagnosed. It is followed by a chronic phase. Most of the infected patients remain asymptomatic all life-long. But 10 or 25 years later, one third of infected patients present with cardiac or digestive complications. Chagas disease is endemic in Latin America, from Mexico to Argentina. In French Guyana, the prevalence of the infection was estimated at 0.25% and 0.5% (from 500 to 1000 infected patients) on blood samples collected from 1992 to 1998. In 2000 and 2009, 192 cases were diagnosed. In this district, there is no established domestic vector and the transmission risk is low. The vector is very easily found in forest habitats and even in the peridomestic persistent forest, with an infection rate of 46 to 86%. Vectorial eradication is impossible. Fighting against Chagas disease in French Guyana relies more on individual protection, control of blood transfusion, prevention of mother-to-child transmission, diagnosis, and treatment of infected patients than on vectorial control. PMID:22591727

  20. Thrust vector control by liquid injection for solid propellant rockets

    NASA Technical Reports Server (NTRS)

    Zeamer, R. J.

    1975-01-01

    In liquid injection thrust vector control, a rocket jet is deflected for steering purposed by injecting a liquid into the nozzle exit cone. The liquid is preferably both dense and reactive so that it adds mass and energy and generates shocks in the supersonic exhaust. This behavior increases thrust in the affected part of the jet producing not only a side force for steering but an addition to axial thrust. This paper presents a summary of current liquid injection thrust vector control technology, including procedures for design, development, analysis, testing and evaluation, together with supporting data and references.

  1. The Burden of Human African Trypanosomiasis

    PubMed Central

    Fèvre, Eric M.; Wissmann, Beatrix v.; Welburn, Susan C.; Lutumba, Pascal

    2008-01-01

    Human African trypanosomiasis (HAT, or sleeping sickness) is a protozoan parasitic infection caused by Trypanosoma brucei rhodesiense or Trypanosoma brucei gambiense. These are neglected tropical diseases, and T.b. rhodesiense HAT is a zoonosis. We review current knowledge on the burden of HAT in sub-Saharan Africa, with an emphasis on the disability-adjusted life year (DALY), data sources, and methodological issues relating to the use of this metric for assessing the burden of this disease. We highlight areas where data are lacking to properly quantify the impact of these diseases, mainly relating to quantifying under-reporting and disability associated with infection, and challenge the HAT research community to tackle the neglect in data gathering to enable better evidence-based assessments of burden using DALYs or other appropriate measures. PMID:19104653

  2. Dengue and Chikungunya Vector Control Pocket Guide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  3. Methods for control of tick vectors of Lyme Borreliosis

    USGS Publications Warehouse

    Jaenson, T.G.T.; Fish, D.; Ginsberg, H.S.; Gray, J.S.; Mather, T.N.; Piesman, J.

    1991-01-01

    During the IVth International Conference on Lyme Borreliosis in Stockholm, 1990, a workshop on control of Lyme disease vectors briefly reviewed: basic ecological principles for tick control; biocontrol of ticks; chemical control, including the use of repellents and use of permethrin-treated rodent nest material; tick control by habitat modification; and reduction of tick host availability. It was concluded that, although much research work remains, Lyme borreliosis is to a large extent a preventable infection. Avoidance of heavily tick-infested areas, personal protection using proper clothing, and prompt removal of attached ticks remain the most effective protective measures. Many other prophylactic measures are available and could be efficiently integrated into schemes to reduce the abundance of vectors. However, since the ecology of the infection varies greatly between different localities it may be necessary to apply different combinations of control methods in different endemic regions.

  4. Application of Lanczos vectors to control design of flexible structures

    NASA Technical Reports Server (NTRS)

    Craig, Roy R., Jr.; Su, Tzu-Jeng

    1990-01-01

    This report covers research conducted during the first year of the two-year grant. The research, entitled 'Application of Lanczos Vectors to Control Design of Flexible Structures' concerns various ways to obtain reduced-order mathematical models for use in dynamic response analyses and in control design studies. This report summarizes research described in several reports and papers that were written under this contract. Extended abstracts are presented for technical papers covering the following topics: controller reduction by preserving impulse response energy; substructuring decomposition and controller synthesis; model reduction methods for structural control design; and recent literature on structural modeling, identification, and analysis.

  5. Vector Disparity Sensor with Vergence Control for Active Vision Systems

    PubMed Central

    Barranco, Francisco; Diaz, Javier; Gibaldi, Agostino; Sabatini, Silvio P.; Ros, Eduardo

    2012-01-01

    This paper presents an architecture for computing vector disparity for active vision systems as used on robotics applications. The control of the vergence angle of a binocular system allows us to efficiently explore dynamic environments, but requires a generalization of the disparity computation with respect to a static camera setup, where the disparity is strictly 1-D after the image rectification. The interaction between vision and motor control allows us to develop an active sensor that achieves high accuracy of the disparity computation around the fixation point, and fast reaction time for the vergence control. In this contribution, we address the development of a real-time architecture for vector disparity computation using an FPGA device. We implement the disparity unit and the control module for vergence, version, and tilt to determine the fixation point. In addition, two on-chip different alternatives for the vector disparity engines are discussed based on the luminance (gradient-based) and phase information of the binocular images. The multiscale versions of these engines are able to estimate the vector disparity up to 32 fps on VGA resolution images with very good accuracy as shown using benchmark sequences with known ground-truth. The performances in terms of frame-rate, resource utilization, and accuracy of the presented approaches are discussed. On the basis of these results, our study indicates that the gradient-based approach leads to the best trade-off choice for the integration with the active vision system. PMID:22438737

  6. Discovering and Designing New Insecticides and their Development Vector Control.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The discovery and development of novel insecticides for vector control is a primary focus of toxicology research conducted at the Mosquito and Fly Research Unit, Gainesville, FL. To identify new active ingredients, the screening of large numbers of experimental compounds is conducted using a primary...

  7. Attitude control of a spinning rocket via thrust vectoring

    SciTech Connect

    White, J.E.

    1990-12-19

    Two controllers are developed to provide attitude control of a spinning rocket that has a thrust vectoring capability. The first controller has a single-input/single-output design that ignores the gyroscopic coupling between the control channels. The second controller has a multi-input/multi-output structure that is specifically intended to account for the gyroscopic coupling effects. A performance comparison between the two approached is conducted for a range of roll rates. Each controller is tested for the ability to track step commands, and for the amount of coupling impurity. Both controllers are developed via a linear-quadratic-regulator synthesis procedure, which is motivated by the multi-input/multi-output nature of second controller. Time responses and a singular value analysis are used to evaluate controller performance. This paper describes the development and comparison of two controllers that are designed to provide attitude control of a spinning rocket that is equipped with thrust vector control. 12 refs., 13 figs., 2 tabs.

  8. Topographic models for predicting malaria vector breeding habitats: potential tools for vector control managers

    PubMed Central

    2013-01-01

    Background Identification of malaria vector breeding sites can enhance control activities. Although associations between malaria vector breeding sites and topography are well recognized, practical models that predict breeding sites from topographic information are lacking. We used topographic variables derived from remotely sensed Digital Elevation Models (DEMs) to model the breeding sites of malaria vectors. We further compared the predictive strength of two different DEMs and evaluated the predictability of various habitat types inhabited by Anopheles larvae. Methods Using GIS techniques, topographic variables were extracted from two DEMs: 1) Shuttle Radar Topography Mission 3 (SRTM3, 90-m resolution) and 2) the Advanced Spaceborne Thermal Emission Reflection Radiometer Global DEM (ASTER, 30-m resolution). We used data on breeding sites from an extensive field survey conducted on an island in western Kenya in 2006. Topographic variables were extracted for 826 breeding sites and for 4520 negative points that were randomly assigned. Logistic regression modelling was applied to characterize topographic features of the malaria vector breeding sites and predict their locations. Model accuracy was evaluated using the area under the receiver operating characteristics curve (AUC). Results All topographic variables derived from both DEMs were significantly correlated with breeding habitats except for the aspect of SRTM. The magnitude and direction of correlation for each variable were similar in the two DEMs. Multivariate models for SRTM and ASTER showed similar levels of fit indicated by Akaike information criterion (3959.3 and 3972.7, respectively), though the former was slightly better than the latter. The accuracy of prediction indicated by AUC was also similar in SRTM (0.758) and ASTER (0.755) in the training site. In the testing site, both SRTM and ASTER models showed higher AUC in the testing sites than in the training site (0.829 and 0.799, respectively). The predictability of habitat types varied. Drains, foot-prints, puddles and swamp habitat types were most predictable. Conclusions Both SRTM and ASTER models had similar predictive potentials, which were sufficiently accurate to predict vector habitats. The free availability of these DEMs suggests that topographic predictive models could be widely used by vector control managers in Africa to complement malaria control strategies. PMID:23324389

  9. Thrust vector control algorithm design for the Cassini spacecraft

    NASA Technical Reports Server (NTRS)

    Enright, Paul J.

    1993-01-01

    This paper describes a preliminary design of the thrust vector control algorithm for the interplanetary spacecraft, Cassini. Topics of discussion include flight software architecture, modeling of sensors, actuators, and vehicle dynamics, and controller design and analysis via classical methods. Special attention is paid to potential interactions with structural flexibilities and propellant dynamics. Controller performance is evaluated in a simulation environment built around a multi-body dynamics model, which contains nonlinear models of the relevant hardware and preliminary versions of supporting attitude determination and control functions.

  10. Discovery of Infection Associated Metabolic Markers in Human African Trypanosomiasis

    PubMed Central

    Lamour, Sabrina D.; Gomez-Romero, Maria; Vorkas, Panagiotis A.; Alibu, Vincent P.; Saric, Jasmina; Holmes, Elaine; Sternberg, Jeremy M.

    2015-01-01

    Human African trypanosomiasis (HAT) remains a major neglected tropical disease in Sub-Saharan Africa. As clinical symptoms are usually non-specific, new diagnostic and prognostic markers are urgently needed to enhance the number of identified cases and optimise treatment. This is particularly important for disease caused by Trypanosoma brucei rhodesiense, where indirect immunodiagnostic approaches have to date been unsuccessful. We have conducted global metabolic profiling of plasma from T.b.rhodesiense HAT patients and endemic controls, using 1H nuclear magnetic resonance (NMR) spectroscopy and ultra-performance liquid chromatography, coupled with mass spectrometry (UPLC-MS) and identified differences in the lipid, amino acid and metabolite profiles. Altogether 16 significantly disease discriminatory metabolite markers were found using NMR, and a further 37 lipid markers via UPLC-MS. These included significantly higher levels of phenylalanine, formate, creatinine, N-acetylated glycoprotein and triglycerides in patients relative to controls. HAT patients also displayed lower concentrations of histidine, sphingomyelins, lysophosphatidylcholines, and several polyunsaturated phosphatidylcholines. While the disease metabolite profile was partially consistent with previous data published in experimental rodent infection, we also found unique lipid and amino acid profile markers highlighting subtle but important differences between the host response to trypanosome infections between animal models and natural human infections. Our results demonstrate the potential of metabolic profiling in the identification of novel diagnostic biomarkers and the elucidation of pathogenetic mechanisms in this disease. PMID:26505639

  11. Costs Of Using “Tiny Targets” to Control Glossina fuscipes fuscipes, a Vector of Gambiense Sleeping Sickness in Arua District of Uganda

    PubMed Central

    Shaw, Alexandra P. M.; Tirados, Inaki; Mangwiro, Clement T. N.; Esterhuizen, Johan; Lehane, Michael J.; Torr, Stephen J.; Kovacic, Vanja

    2015-01-01

    Introduction To evaluate the relative effectiveness of tsetse control methods, their costs need to be analysed alongside their impact on tsetse populations. Very little has been published on the costs of methods specifically targeting human African trypanosomiasis Methodology/Principal Findings In northern Uganda, a 250 km2 field trial was undertaken using small (0.5 X 0.25 m) insecticide-treated targets (“tiny targets”). Detailed cost recording accompanied every phase of the work. Costs were calculated for this operation as if managed by the Ugandan vector control services: removing purely research components of the work and applying local salaries. This calculation assumed that all resources are fully used, with no spare capacity. The full cost of the operation was assessed at USD 85.4 per km2, of which USD 55.7 or 65.2% were field costs, made up of three component activities (target deployment: 34.5%, trap monitoring: 10.6% and target maintenance: 20.1%). The remaining USD 29.7 or 34.8% of the costs were for preliminary studies and administration (tsetse surveys: 6.0%, sensitisation of local populations: 18.6% and office support: 10.2%). Targets accounted for only 12.9% of the total cost, other important cost components were labour (24.1%) and transport (34.6%). Discussion Comparison with the updated cost of historical HAT vector control projects and recent estimates indicates that this work represents a major reduction in cost levels. This is attributed not just to the low unit cost of tiny targets but also to the organisation of delivery, using local labour with bicycles or motorcycles. Sensitivity analyses were undertaken, investigating key prices and assumptions. It is believed that these costs are generalizable to other HAT foci, although in more remote areas, with denser vegetation and fewer people, costs would increase, as would be the case for other tsetse control techniques. PMID:25811956

  12. Attitude Control for an Aero-Vehicle Using Vector Thrusting and Variable Speed Control Moment Gyros

    NASA Technical Reports Server (NTRS)

    Shin, Jong-Yeob; Lim, K. B.; Moerder, D. D.

    2005-01-01

    Stabilization of passively unstable thrust-levitated vehicles can require significant control inputs. Although thrust vectoring is a straightforward choice for realizing these inputs, this may lead to difficulties discussed in the paper. This paper examines supplementing thrust vectoring with Variable-Speed Control Moment Gyroscopes (VSCMGs). The paper describes how to allocate VSCMGs and the vectored thrust mechanism for attitude stabilization in frequency domain and also shows trade-off between vectored thrust and VSCMGs. Using an H2 control synthesis methodology in LMI optimization, a feedback control law is designed for a thrust-levitated research vehicle and is simulated with the full nonlinear model. It is demonstrated that VSCMGs can reduce the use of vectored thrust variation for stabilizing the hovering platform in the presence of strong wind gusts.

  13. Adaptive support vector regression for UAV flight control.

    PubMed

    Shin, Jongho; Jin Kim, H; Kim, Youdan

    2011-01-01

    This paper explores an application of support vector regression for adaptive control of an unmanned aerial vehicle (UAV). Unlike neural networks, support vector regression (SVR) generates global solutions, because SVR basically solves quadratic programming (QP) problems. With this advantage, the input-output feedback-linearized inverse dynamic model and the compensation term for the inversion error are identified off-line, which we call I-SVR (inversion SVR) and C-SVR (compensation SVR), respectively. In order to compensate for the inversion error and the unexpected uncertainty, an online adaptation algorithm for the C-SVR is proposed. Then, the stability of the overall error dynamics is analyzed by the uniformly ultimately bounded property in the nonlinear system theory. In order to validate the effectiveness of the proposed adaptive controller, numerical simulations are performed on the UAV model. PMID:20970303

  14. Fault tolerant vector control of induction motor drive

    NASA Astrophysics Data System (ADS)

    Odnokopylov, G.; Bragin, A.

    2014-10-01

    For electric composed of technical objects hazardous industries, such as nuclear, military, chemical, etc. an urgent task is to increase their resiliency and survivability. The construction principle of vector control system fault-tolerant asynchronous electric. Displaying recovery efficiency three-phase induction motor drive in emergency mode using two-phase vector control system. The process of formation of a simulation model of the asynchronous electric unbalance in emergency mode. When modeling used coordinate transformation, providing emergency operation electric unbalance work. The results of modeling transient phase loss motor stator. During a power failure phase induction motor cannot save circular rotating field in the air gap of the motor and ensure the restoration of its efficiency at rated torque and speed.

  15. Design and test of electromechanical actuators for thrust vector control

    NASA Technical Reports Server (NTRS)

    Cowan, J. R.; Weir, Rae Ann

    1993-01-01

    New control mechanisms technologies are currently being explored to provide alternatives to hydraulic thrust vector control (TVC) actuation systems. For many years engineers have been encouraging the investigation of electromechanical actuators (EMA) to take the place of hydraulics for spacecraft control/gimballing systems. The rationale is to deliver a lighter, cleaner, safer, more easily maintained, as well as energy efficient space vehicle. In light of this continued concern to improve the TVC system, the Propulsion Laboratory at the NASA George C. Marshall Space Flight Center (MSFC) is involved in a program to develop electromechanical actuators for the purpose of testing and TVC system implementation. Through this effort, an electromechanical thrust vector control actuator has been designed and assembled. The design consists of the following major components: Two three-phase brushless dc motors, a two pass gear reduction system, and a roller screw, which converts rotational input into linear output. System control is provided by a solid-state electronic controller and power supply. A pair of resolvers and associated electronics deliver position feedback to the controller such that precise positioning is achieved. Testing and evaluation is currently in progress. Goals focus on performance comparisons between EMA's and similar hydraulic systems.

  16. Energy-saving technology of vector controlled induction motor based on the adaptive neuro-controller

    NASA Astrophysics Data System (ADS)

    Engel, E.; Kovalev, I. V.; Karandeev, D.

    2015-10-01

    The ongoing evolution of the power system towards a Smart Grid implies an important role of intelligent technologies, but poses strict requirements on their control schemes to preserve stability and controllability. This paper presents the adaptive neuro-controller for the vector control of induction motor within Smart Gird. The validity and effectiveness of the proposed energy-saving technology of vector controlled induction motor based on adaptive neuro-controller are verified by simulation results at different operating conditions over a wide speed range of induction motor.

  17. Forebody vortex control as a complement to thrust vectoring

    NASA Technical Reports Server (NTRS)

    Malcolm, G. N.; Ng, T. T.

    1990-01-01

    The desire to enhance the controllability of fighter aircraft at high angles of attack, particularly yaw control, has fostered an interest in both vectored thrust and active control of forebody vortices. This paper reviews several methods of forebody vortex control that have been investigated with water and wind tunnel tests of both generic and actual fighter configurations. The methods investigated include pneumatic or blowing techniques using surface-mounted jets and slots, surface suction, variable-height deployable strakes, and rotatable tip strakes. Flow visualization, and force and moment measurements have shown that all of the methods are effective in manipulating the forebody vortices over a wide range of angles of attack and sideslip, primarily through control over flow separation on the surface of the forebody. All are most effective when applied near the forebody tip. The advantages and limitations of the various methods are reviewed.

  18. Harnessing mosquito-Wolbachia symbiosis for vector and disease control.

    PubMed

    Bourtzis, Kostas; Dobson, Stephen L; Xi, Zhiyong; Rasgon, Jason L; Calvitti, Maurizio; Moreira, Luciano A; Bossin, Hervé C; Moretti, Riccardo; Baton, Luke Anthony; Hughes, Grant L; Mavingui, Patrick; Gilles, Jeremie R L

    2014-04-01

    Mosquito species, members of the genera Aedes, Anopheles and Culex, are the major vectors of human pathogens including protozoa (Plasmodium sp.), filariae and of a variety of viruses (causing dengue, chikungunya, yellow fever, West Nile). There is lack of efficient methods and tools to treat many of the diseases caused by these major human pathogens, since no efficient vaccines or drugs are available; even in malaria where insecticide use and drug therapies have reduced incidence, 219 million cases still occurred in 2010. Therefore efforts are currently focused on the control of vector populations. Insecticides alone are insufficient to control mosquito populations since reduced susceptibility and even resistance is being observed more and more frequently. There is also increased concern about the toxic effects of insecticides on non-target (even beneficial) insect populations, on humans and the environment. During recent years, the role of symbionts in the biology, ecology and evolution of insect species has been well-documented and has led to suggestions that they could potentially be used as tools to control pests and therefore diseases. Wolbachia is perhaps the most renowned insect symbiont, mainly due to its ability to manipulate insect reproduction and to interfere with major human pathogens thus providing new avenues for pest control. We herein present recent achievements in the field of mosquito-Wolbachia symbiosis with an emphasis on Aedes albopictus. We also discuss how Wolbachia symbiosis can be harnessed for vector control as well as the potential to combine the sterile insect technique and Wolbachia-based approaches for the enhancement of population suppression programs. PMID:24252486

  19. Underpinning Sustainable Vector Control through Informed Insecticide Resistance Management

    PubMed Central

    Hemmings, Kay; Hughes, Angela J.; Chanda, Emmanuel; Musapa, Mulenga; Kamuliwo, Mulakwa; Phiri, Faustina N.; Muzia, Lucy; Chanda, Javan; Kandyata, Alister; Chirwa, Brian; Poer, Kathleen; Hemingway, Janet; Wondji, Charles S.; Ranson, Hilary; Coleman, Michael

    2014-01-01

    Background There has been rapid scale-up of malaria vector control in the last ten years. Both of the primary control strategies, long-lasting pyrethroid treated nets and indoor residual spraying, rely on the use of a limited number of insecticides. Insecticide resistance, as measured by bioassay, has rapidly increased in prevalence and has come to the forefront as an issue that needs to be addressed to maintain the sustainability of malaria control and the drive to elimination. Zambia's programme reported high levels of resistance to the insecticides it used in 2010, and, as a result, increased its investment in resistance monitoring to support informed resistance management decisions. Methodology/Principal Findings A country-wide survey on insecticide resistance in Zambian malaria vectors was performed using WHO bioassays to detect resistant phenotypes. Molecular techniques were used to detect target-site mutations and microarray to detect metabolic resistance mechanisms. Anopheles gambiae s.s. was resistant to pyrethroids, DDT and carbamates, with potential organophosphate resistance in one population. The resistant phenotypes were conferred by both target-site and metabolic mechanisms. Anopheles funestus s.s. was largely resistant to pyrethroids and carbamates, with potential resistance to DDT in two locations. The resistant phenotypes were conferred by elevated levels of cytochrome p450s. Conclusions/Significance Currently, the Zambia National Malaria Control Centre is using these results to inform their vector control strategy. The methods employed here can serve as a template to all malaria-endemic countries striving to create a sustainable insecticide resistance management plan. PMID:24932861

  20. Geospatial Risk Factors of Canine American Trypanosomiasis (Chagas Disease) (42 Cases: 2000-2012).

    PubMed

    Raghavan, Ram K; Saunders, Ashley B; Goodin, Doug G; Anderson, Gary A; Harkin, Kenneth R

    2015-10-01

    American trypanosomiasis or Chagas disease caused by Trypanosoma cruzi affects many mammals, including humans and dogs, in all Latin American countries outside the Caribbean and increasingly also in the southern United States. Dogs are considered as reliable sentinels and have been identified as an important risk factor for the disease in humans in endemic countries. Factors that determine American trypanosomiasis in dogs may therefore have public health relevance. Associations of different environmental, locational, and pet owner socioeconomic conditions were evaluated retrospectively as potential risk factors for American trypanosomiasis status in dogs in a case-control study. Laboratory-confirmed cases received at the Texas A&M University Veterinary Medical Teaching Hospital between the years 2000 and 2012 and candidate risk factor variables extracted from publicly available environmental data and 2010 US Census Bureau were used. The sample included 42 dogs serologically positive and 82 dogs serologically negative determined by indirect immunofluorescent assay. The diagnostic titer was 1:160 (case). Univariate logistic regressions followed by stepwise multivariate logistic modeling were used for variable screening and to determine the strengths of variable associations with case status. Total Edge Contrast Index (odds ratio [OR]?=?3.35, 95% confidence interval [CI] 3.10, 3.62), residing in homes that had rural addresses (OR?=?2.48, 95% CI 2.43, 2.53), total number of owner occupied housing units in a neighborhood with a householder who is Hispanic or Latino (OR?=?1.66, 95% CI 1.04, 2.66), and the total number of housing units in a neighborhood that were built on or prior to year 1980 (OR?=?2.22, 95% CI 1.94, 2.55) were identified as risk factors. Suitable awareness campaigns and future research that considers pet owner housing and socioeconomic circumstances are necessary for effective prevention and control of this disease among dogs. PMID:26393300

  1. Stakeholder Narratives on Trypanosomiasis, Their Effect on Policy and the Scope for One Health

    PubMed Central

    Grant, Catherine; Anderson, Neil; Machila, Noreen

    2015-01-01

    Background This paper explores the framings of trypanosomiasis, a widespread and potentially fatal zoonotic disease transmitted by tsetse flies (Glossina species) affecting both humans and livestock. This is a country case study focusing on the political economy of knowledge in Zambia. It is a pertinent time to examine this issue as human population growth and other factors have led to migration into tsetse-inhabited areas with little historical influence from livestock. Disease transmission in new human-wildlife interfaces such as these is a greater risk, and opinions on the best way to manage this are deeply divided. Methods A qualitative case study method was used to examine the narratives on trypanosomiasis in the Zambian policy context through a series of key informant interviews. Interviewees included key actors from international organisations, research organisations and local activists from a variety of perspectives acknowledging the need to explore the relationships between the human, animal and environmental sectors. Principal Findings Diverse framings are held by key actors looking from, variously, the perspectives of wildlife and environmental protection, agricultural development, poverty alleviation, and veterinary and public health. From these viewpoints, four narratives about trypanosomiasis policy were identified, focused around four different beliefs: that trypanosomiasis is protecting the environment, is causing poverty, is not a major problem, and finally, that it is a Zambian rather than international issue to contend with. Within these narratives there are also conflicting views on the best control methods to use and different reasoning behind the pathways of response. These are based on apparently incompatible priorities of people, land, animals, the economy and the environment. The extent to which a One Health approach has been embraced and the potential usefulness of this as a way of reconciling the aims of these framings and narratives is considered throughout the paper. Conclusions/Significance While there has historically been a lack of One Health working in this context, the complex, interacting factors that impact the disease show the need for cross-sector, interdisciplinary decision making to stop rival narratives leading to competing actions. Additional recommendations include implementing: surveillance to assess under-reporting of disease and consequential under-estimation of disease risk; evidence-based decision making; increased and structurally managed funding across countries; and focus on interactions between disease drivers, disease incidence at the community level, and poverty and equity impacts. PMID:26658646

  2. 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. PMID:26416116

  3. Emergence and Prevalence of Human Vector-Borne Diseases in Sink Vector Populations

    PubMed Central

    Rascalou, Guilhem; Pontier, Dominique; Menu, Frédéric; Gourbière, Sébastien

    2012-01-01

    Vector-borne diseases represent a major public health concern in most tropical and subtropical areas, and an emerging threat for more developed countries. Our understanding of the ecology, evolution and control of these diseases relies predominantly on theory and data on pathogen transmission in large self-sustaining ‘source’ populations of vectors representative of highly endemic areas. However, there are numerous places where environmental conditions are less favourable to vector populations, but where immigration allows them to persist. We built an epidemiological model to investigate the dynamics of six major human vector borne-diseases in such non self-sustaining ‘sink’ vector populations. The model was parameterized through a review of the literature, and we performed extensive sensitivity analysis to look at the emergence and prevalence of the pathogen that could be encountered in these populations. Despite the low vector abundance in typical sink populations, all six human diseases were able to spread in 15–55% of cases after accidental introduction. The rate of spread was much more strongly influenced by vector longevity, immigration and feeding rates, than by transmission and virulence of the pathogen. Prevalence in humans remained lower than 5% for dengue, leishmaniasis and Japanese encephalitis, but substantially higher for diseases with longer duration of infection; malaria and the American and African trypanosomiasis. Vector-related parameters were again the key factors, although their influence was lower than on pathogen emergence. Our results emphasize the need for ecology and evolution to be thought in the context of metapopulations made of a mosaic of sink and source habitats, and to design vector control program not only targeting areas of high vector density, but working at a larger spatial scale. PMID:22629337

  4. A review of ecological factors associated with the epidemiology of wildlife trypanosomiasis in the luangwa and zambezi valley ecosystems of zambia.

    PubMed

    Munang'andu, Hetron Mweemba; Siamudaala, Victor; Munyeme, Musso; Nalubamba, King Shimumbo

    2012-01-01

    Trypanosomiasis has been endemic in wildlife in Zambia for more than a century. The disease has been associated with neurological disorders in humans. Current conservation strategies by the Zambian government of turning all game reserves into state-protected National Parks (NPs) and game management areas (GMAs) have led to the expansion of the wildlife and tsetse population in the Luangwa and Zambezi valley ecosystem. This ecological niche lies in the common tsetse fly belt that harbors the highest tsetse population density in Southern Africa. Ecological factors such as climate, vegetation and rainfall found in this niche allow for a favorable interplay between wild reservoir hosts and vector tsetse flies. These ecological factors that influence the survival of a wide range of wildlife species provide adequate habitat for tsetse flies thereby supporting the coexistence of disease reservoir hosts and vector tsetse flies leading to prolonged persistence of trypanosomiasis in the area. On the other hand, increase in anthropogenic activities poses a significant threat of reducing the tsetse and wildlife habitat in the area. Herein, we demonstrate that while conservation of wildlife and biodiversity is an important preservation strategy of natural resources, it could serve as a long-term reservoir of wildlife trypanosomiasis. PMID:22693499

  5. Trypanosoma cruzi: adaptation to its vectors and its hosts

    PubMed Central

    Noireau, François; Diosque, Patricio; Jansen, Ana Maria

    2009-01-01

    American trypanosomiasis is a parasitic zoonosis that occurs throughout Latin America. The etiological agent, Trypanosoma cruzi, is able to infect almost all tissues of its mammalian hosts and spreads in the environment in multifarious transmission cycles that may or not be connected. This biological plasticity, which is probably the result of the considerable heterogeneity of the taxon, exemplifies a successful adaptation of a parasite resulting in distinct outcomes of infection and a complex epidemiological pattern. In the 1990s, most endemic countries strengthened national control programs to interrupt the transmission of this parasite to humans. However, many obstacles remain to the effective control of the disease. Current knowledge of the different components involved in elaborate system that is American trypanosomiasis (the protozoan parasite T. cruzi, vectors Triatominae and the many reservoirs of infection), as well as the interactions existing within the system, is still incomplete. The Triatominae probably evolve from predatory reduvids in response to the availability of vertebrate food source. However, the basic mechanisms of adaptation of some of them to artificial ecotopes remain poorly understood. Nevertheless, these adaptations seem to be associated with a behavioral plasticity, a reduction in the genetic repertoire and increasing developmental instability. PMID:19250627

  6. Space Transportation System solid rocket booster thrust vector control system

    NASA Technical Reports Server (NTRS)

    Verble, A. J., Jr.; Mccool, A. A.; Potter, J. H.

    1980-01-01

    The Solid Rocket Booster, Thrust Vector Control (TVC) system was designed in accordance with the following requirements: self-contained power supply, failsafe operation, 20 flight uses after exposure to seawater landings, optimized cost, and component interchangeability. Trade studies were performed which led to the selection of a recirculating hydraulic system powered by Auxiliary Power Units (APU) which drive the hydraulic actuators and gimbal the solid rocket motor nozzle. Other approaches for the system design were studied in arriving at the recirculating hydraulic system powered by an APU. These systems must withstand the imposed environment and be usable for a minimum of 20 Space Transportation System flights with a minimum of refurbishment. The TVC system completed the required qualification and verification tests and is certified for the intended application. Substantiation data include analytical and test data.

  7. Space transportation system solid rocket booster thrust vector control system

    NASA Technical Reports Server (NTRS)

    Verble, A. J., Jr.; Mccool, A. A.; Potter, J. H.

    1979-01-01

    The Solid Rocket Booster, Thrust Vector Control (TVC) system was designed in accordance with the following requirements: self-contained power supply, fail-safe operation, 20 flight uses after exposure to seawater landings, optimized cost, and component interchangeability. Trade studies were performed which led to the selection of a recirculating hydraulic system powered by Auxiliary Power Units (APU) which drive the hydraulic actuators and gimbal the solid rocket motor nozzle. Other approaches for the system design were studied in arriving at the recirculating hydraulic system powered by an APU. These systems must withstand the imposed environment and be usable for a minimum of 20 Space Transportation System flights with a minimum of refurbishment. The TVC system has completed the major portion of qualification and verification tests and is prepared to be cleared for the first Shuttle flight (STS-1). Substantiation data will include analytical and test data.

  8. Plasmid vector with temperature-controlled gene expression

    SciTech Connect

    Kravchenko, V.V.; Yamshchikov, V.F.; Pletnev, A.G.

    1986-02-01

    In plasmid pBR327, a fragment 169 b.p. long including promotor p/sub 3/ of the bla gene has been deleted. The deletional derivative so obtained (pSP2) has been used to construct a recombinant plasmid bearing a fragment of phage lambda DNA with the p/sub R/ promotor and the gene of the temperature-sensitive repressor cI. It has been shown that the plasmid vector so constructed (pCE119) with promotor cR performs repressor-cI-controlled transcription of the bla gene, as a result of which induction for an hour at 42/sup 0/C leads to an almost 100-fold increase in the amount of product of the bla gene as compared with that at 32/sup 0/C. The possibility of the use of plasmid cPE119 for the expression of other genes has been demonstrated for the case of the semisynthetic ..beta..-galactosidase gene of E. coli. In this case, on induction of the cells with recombinant plasmid pCEZ12 for 3 hours at 42/sup 0/C, a 300-fold increase in the amount of active ..beta..-galactosidase, as compared with that at 32/sup 0/C, was observed. It is important to point out that under these conditions (at 42/sup 0/C), at least 99% of the cells containing the plasmid retain the phenotype lacZ/sup +/, which indicates the stability of the proposed vector system

  9. Adult vector control, mosquito ecology and malaria transmission

    PubMed Central

    Brady, Oliver J.; Godfray, H. Charles J.; Tatem, Andrew J.; Gething, Peter W.; Cohen, Justin M.; McKenzie, F. Ellis; Alex Perkins, T.; Reiner, Robert C.; Tusting, Lucy S.; Scott, Thomas W.; Lindsay, Steven W.; Hay, Simon I.; Smith, David L.

    2015-01-01

    Background Standard advice regarding vector control is to prefer interventions that reduce the lifespan of adult mosquitoes. The basis for this advice is a decades-old sensitivity analysis of ‘vectorial capacity’, a concept relevant for most malaria transmission models and based solely on adult mosquito population dynamics. Recent advances in micro-simulation models offer an opportunity to expand the theory of vectorial capacity to include both adult and juvenile mosquito stages in the model. Methods In this study we revisit arguments about transmission and its sensitivity to mosquito bionomic parameters using an elasticity analysis of developed formulations of vectorial capacity. Results We show that reducing adult survival has effects on both adult and juvenile population size, which are significant for transmission and not accounted for in traditional formulations of vectorial capacity. The elasticity of these effects is dependent on various mosquito population parameters, which we explore. Overall, control is most sensitive to methods that affect adult mosquito mortality rates, followed by blood feeding frequency, human blood feeding habit, and lastly, to adult mosquito population density. Conclusions These results emphasise more strongly than ever the sensitivity of transmission to adult mosquito mortality, but also suggest the high potential of combinations of interventions including larval source management. This must be done with caution, however, as policy requires a more careful consideration of costs, operational difficulties and policy goals in relation to baseline transmission. PMID:25733562

  10. Characterization of Truck Mounted Atomization Equipment Typically Used in Vector Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The control of arthropods that are vectors of human and animal disease is a high priority for both public health and military officials. As droplet size is a critical factor affecting vector control applications, the droplet size spectra produced by eleven sprayers and three spray formulations were...

  11. Climate Change: Potential Affect on Pesticide Application for Vector Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global climate change has and will in the future contribute to the global burden of vector-borne disease by affecting the spatial and tempral distribution of disease. These changes in disease distributions are a direct result of altering the ecology of immature and adult habitats of insect vectors....

  12. Modeling and vector control of planar magnetic levitator

    SciTech Connect

    Kim, W.; Trumper, D.L.; Lang, J.H.

    1998-11-01

    The authors designed and implemented a magnetically levitated stage with large planar motion capability. This planar magnetic levitator employs four novel permanent-magnet linear motors. Each motor generates vertical force for suspension against gravity, as well as horizontal force for drive. These linear levitation motors can be used as building blocks in the general class of multi-degree-of-freedom motion stages. In this paper, the authors discuss electromechanical modeling and real-time vector control of such a permanent-magnet levitator. They describe the dynamics in a dq frame introduced to decouple the forces acting on the magnetically levitated moving part, namely, the platen. A transformation similar to the Blondel-Park transformation is derived for commutation of the stator phase currents. The authors provide test results on step responses of the magnetically levitated stage. It shows 5-nm rms positioning noise in x and y, which demonstrates the applicability of such stages in the next-generation photolithography in semiconductor manufacturing.

  13. Disruptive technology for vector control: the Innovative Vector Control Consortium and the US Military join forces to explore transformative insecticide application technology for mosquito control programmes.

    PubMed

    Knapp, Jennifer; Macdonald, Michael; Malone, David; Hamon, Nicholas; Richardson, Jason H

    2015-01-01

    Malaria vector control technology has remained largely static for decades and there is a pressing need for innovative control tools and methodology to radically improve the quality and efficiency of current vector control practices. This report summarizes a workshop jointly organized by the Innovative Vector Control Consortium (IVCC) and the Armed Forces Pest Management Board (AFPMB) focused on public health pesticide application technology. Three main topics were discussed: the limitations with current tools and techniques used for indoor residual spraying (IRS), technology innovation to improve efficacy of IRS programmes, and truly disruptive application technology beyond IRS. The group identified several opportunities to improve application technology to include: insuring all IRS programmes are using constant flow valves and erosion resistant tips; introducing compression sprayer improvements that help minimize pesticide waste and human error; and moving beyond IRS by embracing the potential for new larval source management techniques and next generation technology such as unmanned "smart" spray systems. The meeting served to lay the foundation for broader collaboration between the IVCC and AFPMB and partners in industry, the World Health Organization, the Bill and Melinda Gates Foundation and others. PMID:26409879

  14. High-Speed Current dq PI Controller for Vector Controlled PMSM Drive

    PubMed Central

    Reaz, Mamun Bin Ibne; Rahman, Labonnah Farzana; Chang, Tae Gyu

    2014-01-01

    High-speed current controller for vector controlled permanent magnet synchronous motor (PMSM) is presented. The controller is developed based on modular design for faster calculation and uses fixed-point proportional-integral (PI) method for improved accuracy. Current dq controller is usually implemented in digital signal processor (DSP) based computer. However, DSP based solutions are reaching their physical limits, which are few microseconds. Besides, digital solutions suffer from high implementation cost. In this research, the overall controller is realizing in field programmable gate array (FPGA). FPGA implementation of the overall controlling algorithm will certainly trim down the execution time significantly to guarantee the steadiness of the motor. Agilent 16821A Logic Analyzer is employed to validate the result of the implemented design in FPGA. Experimental results indicate that the proposed current dq PI controller needs only 50 ns of execution time in 40 MHz clock, which is the lowest computational cycle for the era. PMID:24574913

  15. High-speed current dq PI controller for vector controlled PMSM drive.

    PubMed

    Marufuzzaman, Mohammad; Reaz, Mamun Bin Ibne; Rahman, Labonnah Farzana; Chang, Tae Gyu

    2014-01-01

    High-speed current controller for vector controlled permanent magnet synchronous motor (PMSM) is presented. The controller is developed based on modular design for faster calculation and uses fixed-point proportional-integral (PI) method for improved accuracy. Current dq controller is usually implemented in digital signal processor (DSP) based computer. However, DSP based solutions are reaching their physical limits, which are few microseconds. Besides, digital solutions suffer from high implementation cost. In this research, the overall controller is realizing in field programmable gate array (FPGA). FPGA implementation of the overall controlling algorithm will certainly trim down the execution time significantly to guarantee the steadiness of the motor. Agilent 16821A Logic Analyzer is employed to validate the result of the implemented design in FPGA. Experimental results indicate that the proposed current dq PI controller needs only 50 ns of execution time in 40 MHz clock, which is the lowest computational cycle for the era. PMID:24574913

  16. Linear matrix inequalities for analysis and control of linear vector second-order systems

    SciTech Connect

    Adegas, Fabiano D.; Stoustrup, Jakob

    2015-11-10

    Many dynamical systems are modeled as vector second-order differential equations. This paper presents analysis and synthesis conditions in terms of LMI with explicit dependence in the coefficient matrices of vector second-order systems. These conditions benefit from the separation between the Lyapunov matrix and the system matrices by introducing matrix multipliers, which potentially reduce conservativeness in hard control problems. Multipliers facilitate the usage of parameter-dependent Lyapunov functions as certificates of stability of uncertain and time-varying vector second-order systems. The conditions introduced in this work have the potential to increase the practice of analyzing and controlling systems directly in vector second-order form.

  17. Vector control programs in Saint Johns County, Florida and Guayas, Ecuador: successes and barriers to integrated vector management

    PubMed Central

    2014-01-01

    Background Vector-borne diseases (VBDs) and mosquito control programs (MCPs) diverge in settings and countries, and lead control specialists need to be aware of the most effective control strategies. Integrated Vector Management (IVM) strategies, once implemented in MCPs, aim to reduce cost and optimize protection of the populations against VBDs. This study presents a strengths, weaknesses, opportunities, and threats (SWOT) analysis to compare IVM strategies used by MCPs in Saint Johns County, Florida and Guayas, Ecuador. This research evaluates MCPs strategies to improve vector control activities. Methods Methods included descriptive findings of the MCP operations. Information was obtained from vector control specialists, directors, and residents through field trips, surveys, and questionnaires. Evaluations of the strategies and assets of the control programs where obtained through SWOT analysis and within an IVM approach. Results Organizationally, the Floridian MCP is a tax-based District able to make decisions independently from county government officials, with the oversight of an elected board of commissioners. The Guayas program is directed by the country government and assessed by non-governmental organizations like the World health Organization. Operationally, the Floridian MCP conducts entomological surveillance and the Ecuadorian MCP focuses on epidemiological monitoring of human disease cases. Strengths of both MCPs were their community participation and educational programs. Weaknesses for both MCPs included limitations in budgets and technical capabilities. Opportunities, for both MCPs, are additional funding and partnerships with private, non-governmental, and governmental organizations. Threats experienced by both MCPs included political constraints and changes in the social and ecological environment that affect mosquito densities and control efforts. IVM pillars for policy making were used to compare the information among the programs. Differences included how the Ecuadorian MCP relies heavily on the community for vector control while the American MCP relies on technologies and research. Conclusion IVM based recommendations direct health policy leaders toward improving surveillance systems both entomologically and epidemiologically, improving community risk perceptions by integrating components of community participation, maximizing resources though the use of applied research, and protecting the environment by selecting low-risk pesticides. Outcomes of the research revealed that inter-sectorial and multidisciplinary interventions are critical to improve public health. PMID:24990155

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  19. Olfactory disruption: towards controlling important insect vectors of disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chemical repellents are used to decrease contacts between insect disease vectors and their hosts, thus reducing the probability of disease transmission. The molecular mechanisms by which repellents have their effects are poorly understood and remain a controversial topic. Here we present recent re...

  20. Efficacy of local neem extracts for sustainable malaria vector control in an African village

    E-print Network

    Bomblies, Arne

    Background: Larval control of malaria vectors has been historically successful in reducing malaria transmission, but largely fell out of favour with the introduction of synthetic insecticides and bed nets. However, an ...

  1. The potential for environmental management to contribute to malaria vector control in western Niger

    E-print Network

    Gianotti, Rebecca L. (Rebecca Louise)

    2008-01-01

    This thesis investigated the potential for environmental management techniques to contribute to malaria vector control in Niger, with a case study on Banizoumbou village in western Niger. Numerical modeling was used to ...

  2. Solid rocket booster thrust vector control subsystem test report (D-1)

    NASA Technical Reports Server (NTRS)

    Pagan, B.

    1978-01-01

    The results of the sequence of tests performed on the space shuttle solid rocket booster thrust vector control subsystem are presented. The operational characteristics of the thrust vector control subsystem components, as determined from the tests, are discussed. Special analyses of fuel consumption, basic steady state characteristics, GN2 spin, and actuator displacement were reviewed which will aid in understanding the performance of the auxiliary power unit. The possibility of components malfunction is also discussed.

  3. Developmental Testing of Electric Thrust Vector Control Systems for Manned Launch Vehicle Applications

    NASA Technical Reports Server (NTRS)

    Bates, Lisa B.; Young, David T.

    2012-01-01

    This paper describes recent developmental testing to verify the integration of a developmental electromechanical actuator (EMA) with high rate lithium ion batteries and a cross platform extensible controller. Testing was performed at the Thrust Vector Control Research, Development and Qualification Laboratory at the NASA George C. Marshall Space Flight Center. Electric Thrust Vector Control (ETVC) systems like the EMA may significantly reduce recurring launch costs and complexity compared to heritage systems. Electric actuator mechanisms and control requirements across dissimilar platforms are also discussed with a focus on the similarities leveraged and differences overcome by the cross platform extensible common controller architecture.

  4. Delivery of antihuman African trypanosomiasis drugs across the blood-brain and blood-CSF barriers.

    PubMed

    Sekhar, Gayathri N; Watson, Christopher P; Fidanboylu, Mehmet; Sanderson, Lisa; Thomas, Sarah A

    2014-01-01

    Human African trypanosomiasis (HAT or sleeping sickness) is a potentially fatal disease caused by the parasite, Trypanosoma brucei sp. The parasites are transmitted by the bite of insect vectors belonging to the genus Glossina (tsetse flies) and display a life cycle strategy that is equally spread between human and insect hosts. T.b. gambiense is found in western and central Africa whereas, T.b. rhodesiense is found in eastern and southern Africa. The disease has two clinical stages: a blood stage after the bite of an infected tsetse fly, followed by a central nervous system (CNS) stage where the parasite penetrates the brain; causing death if left untreated. The blood-brain barrier (BBB) makes the CNS stage difficult to treat because it prevents 98% of all known compounds from entering the brain, including some anti-HAT drugs. Those that do enter the brain are toxic compounds in their own right and have serious side effects. There are only a few drugs available to treat HAT and those that do are stage specific. This review summarizes the incidence, diagnosis, and treatment of HAT and provides a close examination of the BBB transport of anti-HAT drugs and an overview of the latest drugs in development. PMID:25307219

  5. VECTOR CONTROL, PEST MANAGEMENT, RESISTANCE, REPELLENTS Effects of Larval Habitat Substrate on Pyriproxyfen Efficacy Against

    E-print Network

    for the control of container-inhabiting mosquitoes. The effects of eight container substrates (three plastics for the container mosquitoes under certain Þeld conditions. KEY WORDS IGR, larval habitat, larval controlVECTOR CONTROL, PEST MANAGEMENT, RESISTANCE, REPELLENTS Effects of Larval Habitat Substrate

  6. Multiaxis aircraft control power from thrust vectoring at high angles of attack

    NASA Technical Reports Server (NTRS)

    Capone, F. J.; Mason, M. L.

    1986-01-01

    Extensive research programs conducted at the Langley Research Center have shown that thrust vectoring can be provided by multifunction (nonaxisymmetric) nozzles. Most of this research has been conducted on pitch vectoring at both static and forward flight conditions. Recent efforts have been aimed at evaluating yaw vectoring concepts at static (wind off) conditions. This paper summarizes results for three different twin-engine fighter configurations tested over a Mach number range of 0.15 to 2.47 at angles of attack up to 35 deg. The objective of these investigations was to determine the multiaxis control power characteristics provided by thrust vectoring. All three configurations employed two-dimensional convergent-divergent nozzles which provided pitch vectoring by differential deflection of the upper and lower nozzle divergent flaps. Three different means of yaw vectoring were tested: (1) a translating nozzle sidewall; (2) yaw flaps located in the nozzle sidewalls; and (3) canted nozzles. These investigations were conducted in the Langley 16-Foot Transonic Tunnel and the Lewis 10x10-Foot Supersonic Tunnel. Longitudinal and direction control power from thrust vectoring was greater than that provided by aerodynamic control effectors at low speed or at high angles of attack.

  7. Will people change their vector-control practices in the presence of an imperfect dengue vaccine?

    PubMed

    Boccia, T M Q R; Burattini, M N; Coutinho, F A B; Massad, E

    2014-03-01

    Human behaviours, which are influenced by social, cultural, economic and political factors, can increase or decrease the risk of dengue infection, depending on the relationship with the insect vector. Because no vaccine is currently available, the spread of dengue can only be curtailed by controlling vector populations (Aedes aegypti and others) and by protecting individuals. This study tested the hypothesis that dengue-affected populations are likely to relax their vector-control habits if a potentially protective vaccine becomes available. The hypothesis was tested using two approaches: a mathematical model designed to describe dengue transmission and an empirical field test in which the local population of an endemic area was interviewed about their vector-control habits given the presence of a theoretical vaccine. The model demonstrated that depending on the level of vector-control reduction, there is a threshold in vaccine efficacy below which it is better not to introduce the vaccine. The interview showed that people who were informed that a very effective vaccine is available would reduce their vector-control habits significantly compared to a group that was informed that the vaccine is not very effective. PMID:23735007

  8. Pastoral livelihoods and the epidemiology of emergent trypanosomiasis on the Jos Plateau, Nigeria 

    E-print Network

    Majekodunmi, Ayodele Oluwakemi

    2012-06-22

    African trypanosomiasis is a widespread disease of livestock which is a major constraint to livestock production, mixed farming and the rural economy. The Jos Plateau in Nigeria was historically free of tsetse flies and ...

  9. Pastoral Livelihoods and the Epidemiology of Emergent Trypanosomiasis on the Jos Plateau, Nigeria 

    E-print Network

    Majekodunmi, Ayodele

    2012-01-01

    African trypanosomiasis is a widespread disease of livestock which is a major constraint to livestock production, mixed farming and the rural economy. The Jos Plateau in Nigeria was historically free of tsetse flies and ...

  10. Seroprevalence of CANINE LEISHMANIASIS AND American trypanosomiasis in dogs from Grenada, West Indies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canine leishmaniasis and American trypanosomiasis (AT) are caused by related hemoflagellated parasites, Leishmania spp. and Trypanosoma cruzi, which share several common host species. Dogs are reservoirs for human infections with both pathogens. We determined the prevalence of antibodies to Leishman...

  11. An agent-vector-host-environment model for controlling small arms and light weapons.

    PubMed

    Pinto, Andrew D; Sharma, Malika; Muggah, Robert

    2011-05-01

    Armed violence is a significant public health problem. It results in fatal and non-fatal injuries and disrupts social and economic processes that are essential to the health of individuals and communities. We argue that an agent-vector-host-environment model can be helpful in understanding and describing the availability and misuse of small arms and light weapons. Moreover, such a model can assist in identifying potential control points and in developing mitigation strategies. These concepts have been developed from analogous vector control programs and are applied to controlling arms to reduce their misuse. So-called 'denormalization' and 'de-legitimization' campaigns that focus on the vector - including the industry producing these commodities - can be based on the experience of public health in controlling tobacco use and exposure. This model can assist health professionals, civil society and governments in developing comprehensive strategies to limit the production, distribution and misuse of small arms and light weapons. PMID:22073533

  12. Sustainable vector control and management of Chagas disease in the Gran Chaco, Argentina

    E-print Network

    Cohen, Joel E.

    Sustainable vector control and management of Chagas disease in the Gran Chaco, Argentina Ricardo E age. Because no effective surveillance and control actions followed the first campaign by Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae), and 40­120 million people are at risk of infection (2

  13. Mosquito vector biology and control in Latin America - a 24th symposium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 24th Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 80th Annual Meeting in Seattle, WA in February 2014. The principal objective, as for the previous 23 symposia, was to promote participation in the AMCA by vector control spe...

  14. MOSQUITO VECTOR CONTROL AND BIOLOGY IN LATIN AMERICA- An 18TH SYMPOSIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 18th Annual Latin American symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 74th Annual Meeting in Sparks, NV, in March 2008. The principal objective, as for the previous 17 symposia, was to promote participation in the AMCA by vector control speci...

  15. Mosquito vector biology and control in Latin America - a 22nd Symposium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 22nd Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 78th Annual Meeting in Austin, TX in February 2012. The principal objective, as for the previous 21 symposia, was to promote participation in the AMCA by vector control spec...

  16. Mosquito vector biology and control in Latin America - A 21st symposium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 21st Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 77th Annual Meeting in Anaheim, CA in March 2011. The principal objective, as for the previous 20 symposia, was to promote participation in the AMCA by vector control specia...

  17. MOSQUITO VECTOR CONTROL AND BIOLOGY IN LATIN AMERICA - A 19TH SYMPOSIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 19th Annual Latin American symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 75th Annual Meeting in New Orleans, LA, in April 2009. The principal objective, as for the previous 18 symposia, was to promote participation in the AMCA by vector control s...

  18. Virus-vectored immunocontraception to control feral cats on islands: a mathematical model

    E-print Network

    Courchamp, Franck

    Virus-vectored immunocontraception to control feral cats on islands: a mathematical model FRANCK CB2 3EJ, UK Summary 1. Feral cats Felis catus introduced onto oceanic islands pose a major ecological of cat control/eradication using immuno- contraception and three dierent disseminating techniques, i

  19. Dengue vector control strategies in an urban setting: an economic modelling assessment

    PubMed Central

    Luz, Paula Mendes; Vanni, Tazio; Medlock, Jan; Paltiel, A David; Galvani, Alison P

    2012-01-01

    Summary Background An estimated 2·5 billion people are at risk of dengue. Incidence of dengue is especially high in resource-constrained countries, where control relies mainly on insecticides targeted at larval or adult mosquitoes. We did epidemiological and economic assessments of different vector control strategies. Methods We developed a dynamic model of dengue transmission that assesses the evolution of insecticide resistance and immunity in the human population, thus allowing for long-term evolutionary and immunological effects of decreased dengue transmission. We measured the dengue health burden in terms of disability-adjusted life-years (DALYs) lost. We did a cost-effectiveness analysis of 43 insecticide-based vector control strategies, including strategies targeted at adult and larval stages, at varying efficacies (high-efficacy [90% mortality], medium-efficacy [60% mortality], and low-efficacy [30% mortality]) and yearly application frequencies (one to six applications). To assess the effect of parameter uncertainty on the results, we did a probabilistic sensitivity analysis and a threshold analysis. Findings All interventions caused the emergence of insecticide resistance, which, with the loss of herd immunity, will increase the magnitude of future dengue epidemics. In our model, one or more applications of high-efficacy larval control reduced dengue burden for up to 2 years, whereas three or more applications of adult vector control reduced dengue burden for up to 4 years. The incremental cost-effectiveness ratios of the strategies for two high-efficacy adult vector control applications per year was US$615 per DALY saved and for six high-efficacy adult vector control applications per year was $1267 per DALY saved. Sensitivity analysis showed that if the cost of adult control was more than 8·2 times the cost of larval control then all strategies based on adult control became dominated. Interpretation Six high-efficacy adult vector control applications per year has a cost-effectiveness ratio that will probably meet WHO's standard for a cost-effective or very cost-effective intervention. Year-round larval control can be counterproductive, exacerbating epidemics in later years because of evolution of insecticide resistance and loss of herd immunity. We suggest the reassessment of vector control policies that are based on larval control only. Funding The Fulbright Programme, CAPES (Brazilian federal agency for post-graduate education), the Miriam Burnett trust, and the Notsew Orm Sands Foundation. PMID:21546076

  20. Sustainability of vector control strategies in the Gran Chaco Region: current challenges and possible approaches

    PubMed Central

    Gürtler, Ricardo E

    2011-01-01

    Sustainability has become a focal point of the international agenda. At the heart of its range of distribution in the Gran Chaco Region, the elimination of Triatoma infestans has failed, even in areas subject to intensive professional vector control efforts. Chagas disease control programs traditionally have been composed of two divorced entities: a vector control program in charge of routine field operations (bug detection and insecticide spraying) and a disease control program in charge of screening blood donors, diagnosis, etiologic treatment and providing medical care to chronic patients. The challenge of sustainable suppression of bug infestation and Trypanosoma cruzi transmission can be met through integrated disease management, in which vector control is combined with active case detection and treatment to increase impact, cost-effectiveness and public acceptance in resource-limited settings. Multi-stakeholder involvement may add sustainability and resilience to the surveillance system. Chagas vector control and disease management must remain a regional effort within the frame of sustainable development rather than being viewed exclusively as a matter of health pertinent to the health sector. Sustained and continuous coordination between governments, agencies, control programs, academia and the affected communities is critical. PMID:19753458

  1. Control-Flow Independence Reuse via Dynamic Vectorization

    E-print Network

    Pajuelo, Alejandro

    in hammock control flow structures resulting from if- then-else constructs. An example is shown in Figure 1 I14: BLE loop Figure 1: Sample code with a hammock. The code in Figure 1 counts how many elements

  2. Regulatory T cells prevent control of experimental African trypanosomiasis.

    PubMed

    Wei, Guojian; Tabel, Henry

    2008-02-15

    African trypanosomes are single-cell, extra-cellular blood parasites causing profound immunosuppression. Susceptible BALB/c mice infected s.c. into a footpad with 10(4) Trypanosoma congolense die with fulminating parasitemia within 10 days. We injected BALB/c mice 2 days before such an infection with different doses of a depleting mAb specific for CD25, a surface marker of regulatory T cells (Tregs). Pretreatment with a low, optimal dose of anti-CD25 resulted in a dramatic effect, in that the infected mice did not develop parasitemia, as well as eliminated all parasites and showed no signs of disease. Their spleens showed a 100% reduction of CD4(+)CD25(high) T cells and overall a 70% reduction of CD4(+)CD25(+)Foxp3(+) T cells 7 days postinfection. The protective effect of treatment with an optimal dose of anti-CD25 could be reversed by administration of l-N6-(1-imminoethyl) lysine, a specific inhibitor of inducible NO synthase or administration of anti-CD8 Ab. Analysis of the cytokine patterns and cell surface marker in infected mice pretreated with anti-CD25 Abs pointed to a potential NKT cell response. We then conducted infections in CD1d(-/-) mice. From our observations, we conclude that CD4(+)CD25(high)Foxp3(+) Tregs prevent, in normal infected susceptible mice, an early protective response mediated by CD8(+) NKT cell-dependent activation of macrophages to kill parasites by production of NO. Our results also indicate that different populations of NKT cells have protective or suppressive effects. Our observations lead us to propose a hypothesis of cross-regulation of NKT cells and Tregs in trypanosome infections. PMID:18250461

  3. Fighting Arbovirus Transmission: Natural and Engineered Control of Vector Competence in Aedes Mosquitoes.

    PubMed

    Kean, Joy; Rainey, Stephanie M; McFarlane, Melanie; Donald, Claire L; Schnettler, Esther; Kohl, Alain; Pondeville, Emilie

    2015-01-01

    Control of aedine mosquito vectors, either by mosquito population reduction or replacement with refractory mosquitoes, may play an essential role in the fight against arboviral diseases. In this review, we will focus on the development and application of biological approaches, both natural or engineered, to limit mosquito vector competence for arboviruses. The study of mosquito antiviral immunity has led to the identification of a number of host response mechanisms and proteins that are required to control arbovirus replication in mosquitoes, though more factors influencing vector competence are likely to be discovered. We will discuss key aspects of these pathways as targets either for selection of naturally resistant mosquito populations or for mosquito genetic manipulation. Moreover, we will consider the use of endosymbiotic bacteria such as Wolbachia, which in some cases have proven to be remarkably efficient in disrupting arbovirus transmission by mosquitoes, but also the use of naturally occurring insect-specific viruses that may interfere with arboviruses in mosquito vectors. Finally, we will discuss the use of paratransgenesis as well as entomopathogenic fungi, which are also proposed strategies to control vector competence. PMID:26463078

  4. Fighting Arbovirus Transmission: Natural and Engineered Control of Vector Competence in Aedes Mosquitoes

    PubMed Central

    Kean, Joy; Rainey, Stephanie M.; McFarlane, Melanie; Donald, Claire L.; Schnettler, Esther; Kohl, Alain; Pondeville, Emilie

    2015-01-01

    Control of aedine mosquito vectors, either by mosquito population reduction or replacement with refractory mosquitoes, may play an essential role in the fight against arboviral diseases. In this review, we will focus on the development and application of biological approaches, both natural or engineered, to limit mosquito vector competence for arboviruses. The study of mosquito antiviral immunity has led to the identification of a number of host response mechanisms and proteins that are required to control arbovirus replication in mosquitoes, though more factors influencing vector competence are likely to be discovered. We will discuss key aspects of these pathways as targets either for selection of naturally resistant mosquito populations or for mosquito genetic manipulation. Moreover, we will consider the use of endosymbiotic bacteria such as Wolbachia, which in some cases have proven to be remarkably efficient in disrupting arbovirus transmission by mosquitoes, but also the use of naturally occurring insect-specific viruses that may interfere with arboviruses in mosquito vectors. Finally, we will discuss the use of paratransgenesis as well as entomopathogenic fungi, which are also proposed strategies to control vector competence. PMID:26463078

  5. Spin vector control of a spinning space station

    NASA Technical Reports Server (NTRS)

    Hendricks, T.

    1971-01-01

    Digital computer program simulates system and related functions. Program is intended for, but not limited to, altitude control studies of rotating space station. Russel's method of formulating and solving motion equations for system of rigid bodies connected by movable joints is applied. Program features are listed.

  6. Evaluation of Nucleoside Hydrolase Inhibitors for Treatment of African Trypanosomiasis ? †

    PubMed Central

    Berg, Maya; Kohl, Linda; Van der Veken, Pieter; Joossens, Jurgen; Al-Salabi, Mohammed I.; Castagna, Valeria; Giannese, Francesca; Cos, Paul; Versées, Wim; Steyaert, Jan; Grellier, Philippe; Haemers, Achiel; Degano, Massimo; Maes, Louis; de Koning, Harry P.; Augustyns, Koen

    2010-01-01

    In this paper, we present the biochemical and biological evaluation of N-arylmethyl-substituted iminoribitol derivatives as potential chemotherapeutic agents against trypanosomiasis. Previously, a library of 52 compounds was designed and synthesized as potent and selective inhibitors of Trypanosoma vivax inosine-adenosine-guanosine nucleoside hydrolase (IAG-NH). However, when the compounds were tested against bloodstream-form Trypanosoma brucei brucei, only one inhibitor, N-(9-deaza-adenin-9-yl)methyl-1,4-dideoxy-1,4-imino-d-ribitol (UAMC-00363), displayed significant activity (mean 50% inhibitory concentration [IC50] ± standard error, 0.49 ± 0.31 ?M). Validation in an in vivo model of African trypanosomiasis showed promising results for this compound. Several experiments were performed to investigate why only UAMC-00363 showed antiparasitic activity. First, the compound library was screened against T. b. brucei IAG-NH and inosine-guanosine nucleoside hydrolase (IG-NH) to confirm the previously demonstrated inhibitory effects of the compounds on T. vivax IAG-NH. Second, to verify the uptake of these compounds by T. b. brucei, their affinities for the nucleoside P1 and nucleoside/nucleobase P2 transporters of T. b. brucei were tested. Only UAMC-00363 displayed significant affinity for the P2 transporter. It was also shown that UAMC-00363 is concentrated in the cell via at least one additional transporter, since P2 knockout mutants of T. b. brucei displayed no resistance to the compound. Consequently, no cross-resistance to the diamidine or the melaminophenyl arsenical classes of trypanocides is expected. Third, three enzymes of the purine salvage pathway of procyclic T. b. brucei (IAG-NH, IG-NH, and methylthioadenosine phosphorylase [MTAP]) were investigated using RNA interference. The findings from all these studies showed that it is probably not sufficient to target only the nucleoside hydrolase activity to block the purine salvage pathway of T. b. brucei and that, therefore, it is possible that UAMC-00363 acts on an additional target. PMID:20194690

  7. A Vector Control for Grid-connected Wind Power Generation with Doubly Fed Induction Generator

    NASA Astrophysics Data System (ADS)

    Kai, Takaaki; Tanaka, Yuji; Kaneda, Hirotoshi; Kobayashi, Daichi; Tanaka, Akio

    Recently, doubly fed induction generator (DFIG) and synchronous generator are mostly applied for wind power generation due to high efficiently for wind energy capture. An inverter system is required to control wind turbine speed and power factor in those generators. The inverter rating of the synchronous generator equals to generator rating. However, DFIG has the advantage that the inverter rating is about 25% to the generator rating. The paper describes a vector control of DFIG inter-connected to power line. The performance of proposed vector control is examined using power system simulation software PSCAD/EMTDC for the DFIG inter-connected to 6.6kv distribution line. The results show good dynamic responses and high accuracy to the stator active power control and the stator reactive power control.

  8. A cluster-randomized trial of insecticide-treated curtains for dengue vector control in Thailand.

    PubMed

    Lenhart, Audrey; Trongtokit, Yuwadee; Alexander, Neal; Apiwathnasorn, Chamnarn; Satimai, Wichai; Vanlerberghe, Veerle; Van der Stuyft, Patrick; McCall, Philip J

    2013-02-01

    The efficacy of insecticide-treated window curtains (ITCs) for dengue vector control was evaluated in Thailand in a cluster-randomized controlled trial. A total of 2,037 houses in 26 clusters was randomized to receive the intervention or act as control (no treatment). Entomological surveys measured Aedes infestations (Breteau index, house index, container index, and pupae per person index) and oviposition indices (mean numbers of eggs laid in oviposition traps) immediately before and after intervention, and at 3-month intervals over 12 months. There were no consistent statistically significant differences in entomological indices between intervention and control clusters, although oviposition indices were lower (P < 0.01) in ITC clusters during the wet season. It is possible that the open housing structures in the study reduced the likelihood of mosquitoes making contact with ITCs. ITCs deployed in a region where this house design is common may be unsuitable for dengue vector control. PMID:23166195

  9. A Cluster-Randomized Trial of Insecticide-Treated Curtains for Dengue Vector Control in Thailand

    PubMed Central

    Lenhart, Audrey; Trongtokit, Yuwadee; Alexander, Neal; Apiwathnasorn, Chamnarn; Satimai, Wichai; Vanlerberghe, Veerle; Van der Stuyft, Patrick; McCall, Philip J.

    2013-01-01

    The efficacy of insecticide-treated window curtains (ITCs) for dengue vector control was evaluated in Thailand in a cluster-randomized controlled trial. A total of 2,037 houses in 26 clusters was randomized to receive the intervention or act as control (no treatment). Entomological surveys measured Aedes infestations (Breteau index, house index, container index, and pupae per person index) and oviposition indices (mean numbers of eggs laid in oviposition traps) immediately before and after intervention, and at 3-month intervals over 12 months. There were no consistent statistically significant differences in entomological indices between intervention and control clusters, although oviposition indices were lower (P < 0.01) in ITC clusters during the wet season. It is possible that the open housing structures in the study reduced the likelihood of mosquitoes making contact with ITCs. ITCs deployed in a region where this house design is common may be unsuitable for dengue vector control. PMID:23166195

  10. Heritable strategies for controlling insect vectors of disease

    PubMed Central

    Burt, Austin

    2014-01-01

    Mosquito-borne diseases are causing a substantial burden of mortality, morbidity and economic loss in many parts of the world, despite current control efforts, and new complementary approaches to controlling these diseases are needed. One promising class of new interventions under development involves the heritable modification of the mosquito by insertion of novel genes into the nucleus or of Wolbachia endosymbionts into the cytoplasm. Once released into a target population, these modifications can act to reduce one or more components of the mosquito population's vectorial capacity (e.g. the number of female mosquitoes, their longevity or their ability to support development and transmission of the pathogen). Some of the modifications under development are designed to be self-limiting, in that they will tend to disappear over time in the absence of recurrent releases (and hence are similar to the sterile insect technique, SIT), whereas other modifications are designed to be self-sustaining, spreading through populations even after releases stop (and hence are similar to traditional biological control). Several successful field trials have now been performed with Aedes mosquitoes, and such trials are helping to define the appropriate developmental pathway for this new class of intervention. PMID:24821918

  11. Heritable strategies for controlling insect vectors of disease.

    PubMed

    Burt, Austin

    2014-01-01

    Mosquito-borne diseases are causing a substantial burden of mortality, morbidity and economic loss in many parts of the world, despite current control efforts, and new complementary approaches to controlling these diseases are needed. One promising class of new interventions under development involves the heritable modification of the mosquito by insertion of novel genes into the nucleus or of Wolbachia endosymbionts into the cytoplasm. Once released into a target population, these modifications can act to reduce one or more components of the mosquito population's vectorial capacity (e.g. the number of female mosquitoes, their longevity or their ability to support development and transmission of the pathogen). Some of the modifications under development are designed to be self-limiting, in that they will tend to disappear over time in the absence of recurrent releases (and hence are similar to the sterile insect technique, SIT), whereas other modifications are designed to be self-sustaining, spreading through populations even after releases stop (and hence are similar to traditional biological control). Several successful field trials have now been performed with Aedes mosquitoes, and such trials are helping to define the appropriate developmental pathway for this new class of intervention. PMID:24821918

  12. Characterization of Spatial Repellent, Contact Irritant and Toxicant Chemical Actions of Standard Vector Control Compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A previously described modular high-throughput screening system (HITTS) was used to characterize the spatial repellent, contact irritant and toxicant chemical actions of 14 compounds with a history of use in vector control. The response of F1-F4 Aedes aegypti to various concentrations of four organo...

  13. Population control of the malaria vector Anopheles pseudopunctipennis by habitat manipulation.

    PubMed Central

    Bond, J. Guillermo; Rojas, Julio C.; Arredondo-Jiménez, Juan I.; Quiroz-Martínez, Humberto; Valle, Javier; Williams, Trevor

    2004-01-01

    Insect vector-borne diseases continue to present a major challenge to human health. Understanding the factors that regulate the size of mosquito populations is considered fundamental to the ability to predict disease transmission rates and for vector population control. The mosquito, Anopheles pseudopunctipennis, a vector of Plasmodium spp., breeds in riverside pools containing filamentous algae in Mesoamerica. Breeding pools along 3 km sections of the River Coatan, Chiapas, Mexico were subjected to algal extraction or left as controls in a cross-over trial extending over 2 years. Initial densities of An. pseudopunctipennis larvae were directly proportional to the prevalence of filamentous algae in each breeding site. The extraction of algae brought about a striking decline in the density of An. pseudopunctipennis larvae sustained for about six weeks, and a concurrent reduction in the adult population in both years of the study. Mark-release experiments indicated that dispersal from adjacent untreated areas was unlikely to exert an important influence on the magnitude of mosquito control that we observed. Habitat manipulation by extraction of filamentous algae offers a unique opportunity for sustainable control of this malaria vector. This technique may represent a valuable intervention, complimenting insecticide spraying of households, to minimize Plasmodium transmission rates in Mesoamerica. PMID:15475337

  14. Solid rocket booster thrust vector control subsystem verification test (V-2) report

    NASA Technical Reports Server (NTRS)

    Pagan, B.

    1979-01-01

    The results of the verification testing sequence V-2 performed on the space shuttle solid rocket booster thrust vector control subsystem are presented. A detailed history of the hot firings plus additional discussion of the auxiliary power unit and the hydraulic component performance is presented. The test objectives, data, and conclusions are included.

  15. Mosquito Vector Control and Biology in Latin America - A 17th Symposium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 17th Annual Latin America American symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 73rd Annual Meeting in Orlando, FL, in April 2007. The principal objective, as for the previous 16 symposia, was to promote participation in the AMCA by vector cont...

  16. Towards thrust vector control with a 3D steerable magnetic nozzle

    E-print Network

    Carlos III de Madrid, Universidad

    Towards thrust vector control with a 3D steerable magnetic nozzle IEPC-2015-414/ISTS-2015-b-414 Presented at Joint Conference of 30th International Symposium on Space Technology and Science, 34th Madrid, Legan´es, Spain A steerable magnetic nozzle concept is presented that enables contactless thrust

  17. MOSQUITO VECTOR CONTROL AND BIOLOGY IN LATIN AMERICA - A 16TH SYMPOSIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 16th Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 72nd Annual Meeting in Detroit, Michigan in February 2006. The principal objective, as for the previous 15 symposia, was to promote participation in the AMCA by vector cont...

  18. Fifteenth IOCV Conference, 2002--Citrus Tristeza Virus Effects of Chemical Control of Aphid Vectors

    E-print Network

    Ma, Lena

    117 Fifteenth IOCV Conference, 2002--Citrus Tristeza Virus Effects of Chemical Control of Aphid-Rodriguez, R. K. Yokomi, P. A. Stansly, and T. K. Riley ABSTRACT. The recent spread of the brown citrus aphid of CTV where T. citri- cida, and other aphid vectors are present. Plots were established with healthy

  19. The Cost of Dengue Vector Control Activities in Malaysia by Different Service Providers.

    PubMed

    Packierisamy, P Raviwharmman; Ng, Chiu-Wan; Dahlui, Maznah; Venugopalan, B; Halasa, Yara A; Shepard, Donald S

    2015-11-01

    We examined variations in dengue vector control costs and resource consumption between the District Health Departments (DHDs) and Local Authorities (LAs) to assist informed decision making as to the future roles of these agencies in the delivery of dengue vector control services in Malaysia. Data were collected from the vector control units of DHDs and LAs in 8 selected districts. We captured costs and resource consumption in 2010 for premise inspection for mosquito breeding sites, fogging to destroy adult mosquitoes and larviciding of potential breeding sites. Overall, DHDs spent US$5.62 million or US$679 per case and LAs spent US$2.61 million or US$499 per case. The highest expenditure for both agencies was for fogging, 51.0% and 45.8% of costs for DHDs and LAs, respectively. The DHDs had higher resource costs for human personnel, vehicles, pesticides, and equipment. The findings provide some evidence to rationalize delivery of dengue vector control services in Malaysia. PMID:26047628

  20. Certifying achievement in the control of Chagas disease native vectors: what is a viable scenario?

    PubMed

    Hashimoto, Ken; Yoshioka, Kota

    2014-09-01

    As an evaluation scheme, we propose certifying for "control", as alternative to "interruption", of Chagas disease transmission by native vectors, to project a more achievable and measurable goal and sharing good practices through an "open online platform" rather than "formal certification" to make the key knowledge more accumulable and accessible. PMID:25317713

  1. Mosquito vector biology and control in Latin America - a 23rd symposium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 23nd Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 79th Annual Meeting in Atlantic City, NJ in February 2013. The principal objective, as for the previous 22 symposia, was to promote participation in the AMCA by vector contr...

  2. VECTOR CONTROL, PEST MANAGEMENT, RESISTANCE, REPELLENTS A Rapid Luminescent Assay for Measuring Cytochrome P450 Activity

    E-print Network

    Hammock, Bruce D.

    VECTOR CONTROL, PEST MANAGEMENT, RESISTANCE, REPELLENTS A Rapid Luminescent Assay for Measuring Cytochrome P450 Activity in Individual Larval Culex pipiens Complex Mosquitoes (Diptera: Culicidae) A. B450 activity in insects, including mosquitoes; however, each of these assays has drawbacks in terms

  3. Using Haptic Vector Fields for Animation Motion Control Technical Report PCS-TR99-353

    E-print Network

    Using Haptic Vector Fields for Animation Motion Control Technical Report PCS-TR99-353 Bruce Randall, 1999 Abstract We are exploring techniques for animation authoring and editing using a haptic force-feedback device. In our system, a family of animations is encoded by a bundle of trajectories. This bundle in turn

  4. Intrusive versus domiciliated triatomines and the challenge of adapting vector control practices against Chagas disease

    PubMed Central

    Waleckx, Etienne; Gourbière, Sébastien; Dumonteil, Eric

    2015-01-01

    Chagas disease prevention remains mostly based on triatomine vector control to reduce or eliminate house infestation with these bugs. The level of adaptation of triatomines to human housing is a key part of vector competence and needs to be precisely evaluated to allow for the design of effective vector control strategies. In this review, we examine how the domiciliation/intrusion level of different triatomine species/populations has been defined and measured and discuss how these concepts may be improved for a better understanding of their ecology and evolution, as well as for the design of more effective control strategies against a large variety of triatomine species. We suggest that a major limitation of current criteria for classifying triatomines into sylvatic, intrusive, domiciliary and domestic species is that these are essentially qualitative and do not rely on quantitative variables measuring population sustainability and fitness in their different habitats. However, such assessments may be derived from further analysis and modelling of field data. Such approaches can shed new light on the domiciliation process of triatomines and may represent a key tool for decision-making and the design of vector control interventions. PMID:25993504

  5. Malaria vector control at a crossroads: public health entomology and the drive to elimination.

    PubMed

    Mnzava, Abraham P; Macdonald, Michael B; Knox, Tessa B; Temu, Emmanuel A; Shiff, Clive J

    2014-09-01

    Vector control has been at the core of successful malaria control. However, a dearth of field-oriented vector biologists threatens to undermine global reductions in malaria burden. Skilled cadres are needed to manage insecticide resistance, to maintain coverage with current interventions, to develop new paradigms for tackling 'residual' transmission and to target interventions as transmission becomes increasingly heterogeneous. Recognising this human resource crisis, in September 2013, WHO Global Malaria Programme issued guidance for capacity building in entomology and vector control, including recommendations for countries and implementing partners. Ministries were urged to develop long-range strategic plans for building human resources for public health entomology and vector control (including skills in epidemiology, geographic information systems, operational research and programme management) and to set in place the requisite professional posts and career opportunities. Capacity building and national ownership in all partner projects and a clear exit strategy to sustain human and technical resources after project completion were emphasised. Implementing partners were urged to support global and regional efforts to enhance public health entomology capacity. While the challenges inherent in such capacity building are great, so too are the opportunities to establish the next generation of public health entomologists that will enable programmes to continue on the path to malaria elimination. PMID:25009173

  6. Thailand Momentum on Policy and Practice in Local Legislation on Dengue Vector Control

    PubMed Central

    Bhumiratana, Adisak; Intarapuk, Apiradee; Chujun, Suriyo; Kaewwaen, Wuthichai; Sorosjinda-Nunthawarasilp, Prapa; Koyadun, Surachart

    2014-01-01

    Over a past decade, an administrative decentralization model, adopted for local administration development in Thailand, is replacing the prior centralized (top-down) command system. The change offers challenges to local governmental agencies and other public health agencies at all the ministerial, regional, and provincial levels. A public health regulatory and legislative framework for dengue vector control by local governmental agencies is a national topic of interest because dengue control program has been integrated into healthcare services at the provincial level and also has been given priority in health plans of local governmental agencies. The enabling environments of local administrations are unique, so this critical review focuses on the authority of local governmental agencies responsible for disease prevention and control and on the functioning of local legislation with respect to dengue vector control and practices. PMID:24799896

  7. A direct torque control scheme for permanent magnet synchronous motors based on space vector modulation

    NASA Astrophysics Data System (ADS)

    Su, Xiao-hui; Xu, Shu-Ping

    2013-03-01

    In order to solve the problem of direct torque control (DTC) for permanent magnet synchronous motor (PMSM) related to the flux and the torque ripple and the uncertainty of switching frequency, A novel direct torque control system based on space vector modulation(SVM-DTC) for permanent magnet synchronous motor was proposed. In this method flux and torque are controlled through stator voltage components in stator flux linkage coordinate axes and space vector modulation is used to control inverters. Therefore, the errors of torque and flux linkage could be compensated accurately. The whole system has only one easily adjustable PI adjuster and needs no high for hardware and easy for realize. The simulation results verify the feasibility of this method, reduction of the flux and the torque ripple, and the good performance of DTC.

  8. Vista/F-16 Multi-Axis Thrust Vectoring (MATV) control law design and evaluation

    NASA Technical Reports Server (NTRS)

    Zwerneman, W. D.; Eller, B. G.

    1994-01-01

    For the Multi-Axis Thrust Vectoring (MATV) program, a new control law was developed using multi-axis thrust vectoring to augment the aircraft's aerodynamic control power to provide maneuverability above the normal F-16 angle of attack limit. The control law architecture was developed using Lockheed Fort Worth's offline and piloted simulation capabilities. The final flight control laws were used in flight test to demonstrate tactical benefits gained by using thrust vectoring in air-to-air combat. Differences between the simulator aerodynamics data base and the actual aircraft aerodynamics led to significantly different lateral-directional flying qualities during the flight test program than those identified during piloted simulation. A 'dial-a-gain' flight test control law update was performed in the middle of the flight test program. This approach allowed for inflight optimization of the aircraft's flying qualities. While this approach is not preferred over updating the simulator aerodynamic data base and then updating the control laws, the final selected gain set did provide adequate lateral-directional flying qualities over the MATV flight envelope. The resulting handling qualities and the departure resistance of the aircraft allowed the 422nd_squadron pilots to focus entirely on evaluating the aircraft's tactical utility.

  9. 1066 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 51, NO. 5, OCTOBER 2004 Stator-Flux-Oriented Vector Control of Synchronous

    E-print Network

    Sanders, Seth

    -mentioned advantages is a motor/generator for a flywheel energy storage system [4]. Vector control of synchronous-Flux-Oriented Vector Control of Synchronous Reluctance Machines With Maximized Efficiency Heath F. Hofmann, Member and rotational speed for a synchronous reluctance machine. A model of the synchronous reluctance machine

  10. Genetic shifting: a novel approach for controlling vector-borne diseases

    PubMed Central

    Tabachnick, Walter J.

    2014-01-01

    Rendering populations of vectors of diseases incapable of transmitting pathogens through genetic methods has long been a goal of vector geneticists. We outline a method to achieve this goal that does not involve introduction of any new genetic variants to the target population. Rather we propose that shifting the frequencies of naturally occurring alleles that confer refractoriness to transmission can reduce transmission below a sustainable level. The program employs methods successfully used in plant and animal breeding. Because no artificially constructed genetically modified organisms (GMOs) are introduced into the environment, the method is minimally controversial. We use Aedes aegypti and dengue virus (DENV) for illustrative purposes, but point out the proposed program is generally applicable to vector-borne disease control. PMID:24794113

  11. Genetic shifting: a novel approach for controlling vector-borne diseases.

    PubMed

    Powell, Jeffrey R; Tabachnick, Walter J

    2014-06-01

    Rendering populations of vectors of diseases incapable of transmitting pathogens through genetic methods has long been a goal of vector geneticists. We outline a method to achieve this goal that does not involve the introduction of any new genetic variants to the target population. Rather we propose that shifting the frequencies of naturally occurring alleles that confer refractoriness to transmission can reduce transmission below a sustainable level. The program employs methods successfully used in plant and animal breeding. Because no artificially constructed genetically modified organisms (GMOs) are introduced into the environment, the method is minimally controversial. We use Aedes aegypti and dengue virus (DENV) for illustrative purposes but point out that the proposed program is generally applicable to vector-borne disease control. PMID:24794113

  12. An Assessment of Participatory Integrated Vector Management for Malaria Control in Kenya

    PubMed Central

    Mbogo, Charles; Mwangangi, Joseph; Imbahale, Susan; Kibe, Lydia; Orindi, Benedict; Girma, Melaku; Njui, Annah; Lwande, Wilber; Affognon, Hippolyte; Gichuki, Charity; Mukabana, Wolfgang Richard

    2015-01-01

    Background The World Health Organization (WHO) recommends integrated vector management (IVM) as a strategy to improve and sustain malaria vector control. However, this approach has not been widely adopted. Objectives We comprehensively assessed experiences and findings on IVM in Kenya with a view to sharing lessons that might promote its wider application. Methods The assessment used information from a qualitative external evaluation of two malaria IVM projects implemented between 2006 and 2011 and an analysis of their accumulated entomological and malaria case data. The project sites were Malindi and Nyabondo, located in coastal and western Kenya, respectively. The assessment focused on implementation of five key elements of IVM: integration of vector control methods, evidence-based decision making, intersectoral collaboration, advocacy and social mobilization, and capacity building. Results IVM was more successfully implemented in Malindi than in Nyabondo owing to greater community participation and multistakeholder engagement. There was a significant decline in the proportion of malaria cases among children admitted to Malindi Hospital, from 23.7% in 2006 to 10.47% in 2011 (p < 0.001). However, the projects’ operational research methodology did not allow statistical attribution of the decline in malaria and malaria vectors to specific IVM interventions or other factors. Conclusions Sustaining IVM is likely to require strong participation and support from multiple actors, including community-based groups, non-governmental organizations, international and national research institutes, and various government ministries. A cluster-randomized controlled trial would be essential to quantify the effectiveness and impact of specific IVM interventions, alone or in combination. Citation Mutero CM, Mbogo C, Mwangangi J, Imbahale S, Kibe L, Orindi B, Girma M, Njui A, Lwande W, Affognon H, Gichuki C, Mukabana WR. 2015. An assessment of participatory integrated vector management for malaria control in Kenya. Environ Health Perspect 123:1145–1151; http://dx.doi.org/10.1289/ehp.1408748 PMID:25859686

  13. Drivers, dynamics, and control of emerging vector-borne zoonotic diseases.

    PubMed

    Kilpatrick, A Marm; Randolph, Sarah E

    2012-12-01

    Emerging vector-borne diseases are an important issue in global health. Many vector-borne pathogens have appeared in new regions in the past two decades, while many endemic diseases have increased in incidence. Although introductions and emergence of endemic pathogens are often considered to be distinct processes, many endemic pathogens are actually spreading at a local scale coincident with habitat change. We draw attention to key differences between dynamics and disease burden that result from increased pathogen transmission after habitat change and after introduction into new regions. Local emergence is commonly driven by changes in human factors as much as by enhanced enzootic cycles, whereas pathogen invasion results from anthropogenic trade and travel where and when conditions (eg, hosts, vectors, and climate) are suitable for a pathogen. Once a pathogen is established, ecological factors related to vector characteristics can shape the evolutionary selective pressure and result in increased use of people as transmission hosts. We describe challenges inherent in the control of vector-borne zoonotic diseases and some emerging non-traditional strategies that could be effective in the long term. PMID:23200503

  14. Proteomic Selection of Immunodiagnostic Antigens for Human African Trypanosomiasis and Generation of a Prototype Lateral Flow Immunodiagnostic Device

    PubMed Central

    Sullivan, Lauren; Wall, Steven J.; Carrington, Mark; Ferguson, Michael A. J.

    2013-01-01

    Background The diagnosis of Human African Trypanosomiasis relies mainly on the Card Agglutination Test for Trypanosomiasis (CATT). While this test is successful, it is acknowledged that there may be room for improvement. Our aim was to develop a prototype lateral flow test based on the detection of antibodies to trypanosome antigens. Methodology/Principal Findings We took a non-biased approach to identify potential immunodiagnostic parasite protein antigens. The IgG fractions from the sera from Trypanosoma brucei gambiense infected and control patients were isolated using protein-G affinity chromatography and then immobilized on Sepharose beads. The IgG-beads were incubated with detergent lysates of trypanosomes and those proteins that bound were identified by mass spectrometry-based proteomic methods. This approach provided a list of twenty-four trypanosome proteins that selectively bound to the infection IgG fraction and that might, therefore, be considered as immunodiagnostic antigens. We selected four antigens from this list (ISG64, ISG65, ISG75 and GRESAG4) and performed protein expression trials in E. coli with twelve constructs. Seven soluble recombinant protein products (three for ISG64, two for ISG65 and one each for ISG75 and GRESAG4) were obtained and assessed for their immunodiagnostic potential by ELISA using individual and/or pooled patient sera. The ISG65 and ISG64 construct ELISAs performed well with respect to detecting T. b. gambiense infections, though less well for detecting T. b. rhodesiense infections, and the best performing ISG65 construct was used to develop a prototype lateral flow diagnostic device. Conclusions/Significance Using a panel of eighty randomized T. b. gambiense infection and control sera, the prototype showed reasonable sensitivity (88%) and specificity (93%) using visual readout in detecting T. b. gambiense infections. These results provide encouragement to further develop and optimize the lateral flow device for clinical use. PMID:23469310

  15. Benefit of Insecticide-Treated Nets, Curtains and Screening on Vector Borne Diseases, Excluding Malaria: A Systematic Review and Meta-analysis

    PubMed Central

    Wilson, Anne L.; Dhiman, Ramesh C.; Kitron, Uriel; Scott, Thomas W.; van den Berg, Henk; Lindsay, Steven W.

    2014-01-01

    Introduction Insecticide-treated nets (ITNs) are one of the main interventions used for malaria control. However, these nets may also be effective against other vector borne diseases (VBDs). We conducted a systematic review and meta-analysis to estimate the efficacy of ITNs, insecticide-treated curtains (ITCs) and insecticide-treated house screening (ITS) against Chagas disease, cutaneous and visceral leishmaniasis, dengue, human African trypanosomiasis, Japanese encephalitis, lymphatic filariasis and onchocerciasis. Methods MEDLINE, EMBASE, LILACS and Tropical Disease Bulletin databases were searched using intervention, vector- and disease-specific search terms. Cluster or individually randomised controlled trials, non-randomised trials with pre- and post-intervention data and rotational design studies were included. Analysis assessed the efficacy of ITNs, ITCs or ITS versus no intervention. Meta-analysis of clinical data was performed and percentage reduction in vector density calculated. Results Twenty-one studies were identified which met the inclusion criteria. Meta-analysis of clinical data could only be performed for four cutaneous leishmaniasis studies which together showed a protective efficacy of ITNs of 77% (95%CI: 39%–91%). Studies of ITC and ITS against cutaneous leishmaniasis also reported significant reductions in disease incidence. Single studies reported a high protective efficacy of ITS against dengue and ITNs against Japanese encephalitis. No studies of Chagas disease, human African trypanosomiasis or onchocerciasis were identified. Conclusion There are likely to be considerable collateral benefits of ITN roll out on cutaneous leishmaniasis where this disease is co-endemic with malaria. Due to the low number of studies identified, issues with reporting of entomological outcomes, and few studies reporting clinical outcomes, it is difficult to make strong conclusions on the effect of ITNs, ITCs or ITS on other VBDs and therefore further studies be conducted. Nonetheless, it is clear that insecticide-treated materials such as ITNs have the potential to reduce pathogen transmission and morbidity from VBDs where vectors enter houses. PMID:25299481

  16. Insecticide susceptibility of Phlebotomus argentipes & assessment of vector control in two districts of West Bengal, India

    PubMed Central

    Kumar, Vijay; Shankar, Lokesh; Kesari, Shreekant; Bhunia, Gouri Shankar; Dinesh, Diwakar Singh; Mandal, Rakesh; Das, Pradeep

    2015-01-01

    Background & objectives: Kala-azar or visceral leishmanisis (VL) is known to be endemic in several States of India including West Bengal (WB). Only meager information is available on the vector dynamics of its vector species, Phlebotomus argentipes particularly in relation to control measure from this State. Hence, a pilot study was undertaken to assess the control strategy and its impact on vector in two endemic districts of WB, India. Methods: Two villages each from the two districts, Maldah and Burdwan, were selected for the study. Seasonal variation of sandflies was observed during pre-monsoon, post-monsoon and winter seasons. Susceptibility test of P. argentipes against DDT and bioassay on DDT sprayed wall and on long lasting insecticide nets (LN) Perma Net® 2.0 were conducted as per the WHO standard methods. Results: P. argentipes density was high during March to October. Susceptibility status of P. argentipes ranged from 40 to 61.54 per cent. Bioassay test showed 57.89 per cent mortality against LN PermaNet®-2.0. and 50 per cent against DDT on wall within 30 min of exposure. Interpretation & conclusions: Despite the integrated vector management approach, the sandfly population was high in the study area. The reason could be development of resistance in P. argentipes against DDT and low effectiveness of LN PermaNet®-2.0. The more pragmatic step will be to conduct large studies to monitor the susceptibility level in P. argentipes against DDT. PMID:26354219

  17. An Adaptive Supervisory Sliding Fuzzy Cerebellar Model Articulation Controller for Sensorless Vector-Controlled Induction Motor Drive Systems

    PubMed Central

    Wang, Shun-Yuan; Tseng, Chwan-Lu; Lin, Shou-Chuang; Chiu, Chun-Jung; Chou, Jen-Hsiang

    2015-01-01

    This paper presents the implementation of an adaptive supervisory sliding fuzzy cerebellar model articulation controller (FCMAC) in the speed sensorless vector control of an induction motor (IM) drive system. The proposed adaptive supervisory sliding FCMAC comprised a supervisory controller, integral sliding surface, and an adaptive FCMAC. The integral sliding surface was employed to eliminate steady-state errors and enhance the responsiveness of the system. The adaptive FCMAC incorporated an FCMAC with a compensating controller to perform a desired control action. The proposed controller was derived using the Lyapunov approach, which guarantees learning-error convergence. The implementation of three intelligent control schemes—the adaptive supervisory sliding FCMAC, adaptive sliding FCMAC, and adaptive sliding CMAC—were experimentally investigated under various conditions in a realistic sensorless vector-controlled IM drive system. The root mean square error (RMSE) was used as a performance index to evaluate the experimental results of each control scheme. The analysis results indicated that the proposed adaptive supervisory sliding FCMAC substantially improved the system performance compared with the other control schemes. PMID:25815450

  18. Prospects and recommendations for risk mapping to improve strategies for effective malaria vector control interventions in Latin America.

    PubMed

    Alimi, Temitope O; Fuller, Douglas O; Quinones, Martha L; Xue, Rui-De; Herrera, Socrates V; Arevalo-Herrera, Myriam; Ulrich, Jill N; Qualls, Whitney A; Beier, John C

    2015-01-01

    With malaria control in Latin America firmly established in most countries and a growing number of these countries in the pre-elimination phase, malaria elimination appears feasible. A review of the literature indicates that malaria elimination in this region will be difficult without locally tailored strategies for vector control, which depend on more research on vector ecology, genetics and behavioural responses to environmental changes, such as those caused by land cover alterations, and human population movements. An essential way to bridge the knowledge gap and improve vector control is through risk mapping. Malaria risk maps based on statistical and knowledge-based modelling can elucidate the links between environmental factors and malaria vectors, explain interactions between environmental changes and vector dynamics, and provide a heuristic to demonstrate how the environment shapes malaria transmission. To increase the utility of risk mapping in guiding vector control activities, definitions of malaria risk for mapping purposes must be standardized. The maps must also possess appropriate scale and resolution in order to become essential tools in integrated vector management (IVM), so that planners can target areas in greatest need of control measures. Fully integrating risk mapping into vector control programmes will make interventions more evidence-based, making malaria elimination more attainable. PMID:26694047

  19. Opportunities for Improved Chagas Disease Vector Control Based on Knowledge, Attitudes and Practices of Communities in the Yucatan Peninsula, Mexico

    PubMed Central

    Rosecrans, Kathryn; Cruz-Martin, Gabriela; King, Ashley; Dumonteil, Eric

    2014-01-01

    Background Chagas disease is a vector-borne parasitic disease of major public health importance. Current prevention efforts are based on triatomine vector control to reduce transmission to humans. Success of vector control interventions depends on their acceptability and value to affected communities. We aimed to identify opportunities for and barriers to improved vector control strategies in the Yucatan peninsula, Mexico. Methodology/principal findings We employed a sequence of qualitative and quantitative research methods to investigate knowledge, attitudes and practices surrounding Chagas disease, triatomines and vector control in three rural communities. Our combined data show that community members are well aware of triatomines and are knowledgeable about their habits. However, most have a limited understanding of the transmission dynamics and clinical manifestations of Chagas disease. While triatomine control is not a priority for community members, they frequently use domestic insecticide products including insecticide spray, mosquito coils and plug-in repellents. Families spend about $32 US per year on these products. Alternative methods such as yard cleaning and window screens are perceived as desirable and potentially more effective. Screens are nonetheless described as unaffordable, in spite of a cost comparable to the average annual spending on insecticide products. Conclusion/Significance Further education campaigns and possibly financing schemes may lead families to redirect their current vector control spending from insecticide products to window screens. Also, synergism with mosquito control efforts should be further explored to motivate community involvement and ensure sustainability of Chagas disease vector control. PMID:24676038

  20. 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 minimizing further selection of resistant phenotypes. PMID:24069492

  1. Using Hydrologic Modeling to Screen Potential Environmental Management Methods for Malaria Vector Control in Niger

    NASA Astrophysics Data System (ADS)

    Gianotti, R. L.; Bomblies, A.; Eltahir, E. A.

    2008-12-01

    This study describes the use of HYDREMATS, a physically-based distributed hydrology model, to investigate environmental management methods for malaria vector control in the Sahelian village of Banizoumbou, Niger. The model operates at fine spatial and temporal scales to enable explicit simulation of individual pool dynamics and isolation of mosquito breeding habitats. The results showed that leveling of topographic depressions where temporary breeding habitats form during the rainy season could reduce the persistence time of a pool to less than the time needed for establishment of mosquito breeding, approximately 7 days. Increasing the surface soil permeability by ploughing could also reduce the persistence time of a pool but this technique was not as effective as leveling. Therefore it is considered that leveling should be the preferred of the two options where possible. This investigation demonstrates that management methods that modify the hydrologic environment have significant potential to contribute to malaria vector control and human health improvement in Sahelian Africa.

  2. Hydrologic modeling to screen potential environmental management methods for malaria vector control in Niger

    NASA Astrophysics Data System (ADS)

    Gianotti, Rebecca L.; Bomblies, Arne; Eltahir, Elfatih A. B.

    2009-08-01

    This paper describes the first use of Hydrology-Entomology and Malaria Transmission Simulator (HYDREMATS), a physically based distributed hydrology model, to investigate environmental management methods for malaria vector control in the Sahelian village of Banizoumbou, Niger. The investigation showed that leveling of topographic depressions where temporary breeding habitats form during the rainy season, by altering pool basin microtopography, could reduce the pool persistence time to less than the time needed for establishment of mosquito breeding, approximately 7 days. Undertaking soil surface plowing can also reduce pool persistence time by increasing the infiltration rate through an existing pool basin. Reduction of the pool persistence time to less than the rainfall interstorm period increases the frequency of pool drying events, removing habitat for subadult mosquitoes. Both management approaches could potentially be considered within a given context. This investigation demonstrates that management methods that modify the hydrologic environment have significant potential to contribute to malaria vector control in water-limited, Sahelian Africa.

  3. Integrated malaria vector control with microbial larvicides and insecticide-treated nets in western Kenya: a controlled trial

    PubMed Central

    Fillinger, Ulrike; Ndenga, Bryson; Githeko, Andrew

    2009-01-01

    Abstract Objective To assess the contributions of both microbial larvicides and insecticide-treated nets (ITNs) in terms of reducing malaria incidence in an integrated vector management programme in an area moderately endemic for malaria in the western Kenyan highlands. Methods A pre-post, control group design was used. Larval and adult vector populations were surveyed weekly in six separate valley communities. The incidence of Plasmodium infections in children 6 months to 13 years of age was measured during the long and short rainy seasons each year. Baseline data were collected for 17 months, after which Bacillus-based larvicides were applied weekly to aquatic habitats in three of the valleys for another 19 months. At around the same time the larviciding was initiated, ITNs were introduced gradually into all study communities by the National Malaria Control Programme. The effect of larviciding, ITNs and other determinants of malaria risk was assessed by means of generalized estimating equations. Findings The risk of acquiring new parasite infections in children was substantially and independently reduced by ITN use (odds ratio, OR: 0.69; 95% confidence interval, CI: 0.48–0.99) and larvicide application (OR: 0.44; 95% CI: 0.23–0.82), after adjusting for confounders. Conclusion Vector control with microbial larvicides enhanced the malaria control achieved with ITNs alone. Anti-larval measures are a promising complement to ITN distribution in the economically important highland areas and similar transmission settings in Africa. PMID:19784445

  4. Noise-induced hearing loss and associated factors among vector control workers in a Malaysian state.

    PubMed

    Masilamani, Retneswari; Rasib, Abdul; Darus, Azlan; Ting, Anselm Su

    2014-11-01

    This study aims to determine the prevalence and associated factors of noise-induced hearing loss (NIHL) among vector control workers in the state of Negeri Sembilan, Malaysia. This was an analytical cross-sectional study conducted on 181 vector control workers who were working in district health offices in a state in Malaysia. Data were collected using a self-administered questionnaire and audiometry. Prevalence of NIHL was 26% among this group of workers. NIHL was significantly associated with the age-group of 40 years and older, length of service of 10 or more years, current occupational noise exposure, listening to loud music, history of firearms use, and history of mumps/measles infection. Following logistic regression, age of more than 40 years and noise exposure in current occupation were associated with NIHL with an odds ratio of 3.45 (95% confidence interval = 1.68-7.07) and 6.87 (95% confidence interval = 1.54-30.69), respectively, among this group of vector control workers. PMID:22548779

  5. In silico models for predicting vector control chemicals targeting Aedes aegypti

    PubMed Central

    Devillers, J.; Lagneau, C.; Lattes, A.; Garrigues, J.C.; Clémenté, M.M.; Yébakima, A.

    2014-01-01

    Human arboviral diseases have emerged or re-emerged in numerous countries worldwide due to a number of factors including the lack of progress in vaccine development, lack of drugs, insecticide resistance in mosquitoes, climate changes, societal behaviours, and economical constraints. Thus, Aedes aegypti is the main vector of the yellow fever and dengue fever flaviviruses and is also responsible for several recent outbreaks of the chikungunya alphavirus. As for the other mosquito species, the A. aegypti control relies heavily on the use of insecticides. However, because of increasing resistance to the different families of insecticides, reduction of Aedes populations is becoming increasingly difficult. Despite the unquestionable utility of insecticides in fighting mosquito populations, there are very few new insecticides developed and commercialized for vector control. This is because the high cost of the discovery of an insecticide is not counterbalanced by the ‘low profitability’ of the vector control market. Fortunately, the use of quantitative structure–activity relationship (QSAR) modelling allows the reduction of time and cost in the discovery of new chemical structures potentially active against mosquitoes. In this context, the goal of the present study was to review all the existing QSAR models on A. aegypti. The homology and pharmacophore models were also reviewed. Specific attention was paid to show the variety of targets investigated in Aedes in relation to the physiology and ecology of the mosquito as well as the diversity of the chemical structures which have been proposed, encompassing man-made and natural substances. PMID:25275884

  6. Mapping Neglected Swimming Pools from Satellite Data for Urban Vector Control

    NASA Astrophysics Data System (ADS)

    Barker, C. M.; Melton, F. S.; Reisen, W. K.

    2010-12-01

    Neglected swimming pools provide suitable breeding habit for mosquitoes, can contain thousands of mosquito larvae, and present both a significant nuisance and public health risk due to their inherent proximity to urban and suburban populations. The rapid increase and sustained rate of foreclosures in California associated with the recent recession presents a challenge for vector control districts seeking to identify, treat, and monitor neglected pools. Commercial high resolution satellite imagery offers some promise for mapping potential neglected pools, and for mapping pools for which routine maintenance has been reestablished. We present progress on unsupervised classification techniques for mapping both neglected pools and clean pools using high resolution commercial satellite data and discuss the potential uses and limitations of this data source in support of vector control efforts. An unsupervised classification scheme that utilizes image segmentation, band thresholds, and a change detection approach was implemented for sample regions in Coachella Valley, CA and the greater Los Angeles area. Comparison with field data collected by vector control personal was used to assess the accuracy of the estimates. The results suggest that the current system may provide some utility for early detection, or cost effective and time efficient annual monitoring, but additional work is required to address spectral and spatial limitations of current commercial satellite sensors for this purpose.

  7. The sheep as a potential reservoir of human trypanosomiasis in the Republic of the Congo.

    PubMed

    Scott, C M; Frézil, J L; Toudic, A; Godfrey, D G

    1983-01-01

    The identical electrophoretic isoenzyme patterns of a human-plasma-resistant Trypanozoon stock from a sheep and of two other stocks from trypanosomiasis patients in the Congo Republic indicated that the sheep stock was probably infective to man. These, and one further human stock from the Congo, closely resembled stocks isolated from man in Liberia and Ivory Coast. PMID:6623598

  8. Modest additive effects of integrated vector control measures on malaria prevalence and transmission in western Kenya

    PubMed Central

    2013-01-01

    Background The effect of integrating vector larval intervention on malaria transmission is unknown when insecticide-treated bed-net (ITN) coverage is very high, and the optimal indicator for intervention evaluation needs to be determined when transmission is low. Methods A post hoc assignment of intervention-control cluster design was used to assess the added effect of both indoor residual spraying (IRS) and Bacillus-based larvicides (Bti) in addition to ITN in the western Kenyan highlands in 2010 and 2011. Cross-sectional, mass parasite screenings, adult vector populations, and cohort of active case surveillance (ACS) were conducted before and after the intervention in three study sites with two- to three-paired intervention-control clusters at each site each year. The effect of larviciding, IRS, ITNs and other determinants of malaria risk was assessed by means of mixed estimating methods. Results Average ITN coverage increased from 41% in 2010 to 92% in 2011 in the study sites. IRS intervention had significant added impact on reducing vector density in 2010 but the impact was modest in 2011. The effect of IRS on reducing parasite prevalence was significant in 2011 but was seasonal specific in 2010. ITN was significantly associated with parasite densities in 2010 but IRS application was significantly correlated with reduced gametocyte density in 2011. IRS application reduced about half of the clinical malaria cases in 2010 and about one-third in 2011 compare to non-intervention areas. Conclusion Compared with a similar study conducted in 2005, the efficacy of the current integrated vector control with ITN, IRS, and Bti reduced three- to five-fold despite high ITN coverage, reflecting a modest added impact on malaria transmission. Additional strategies need to be developed to further reduce malaria transmission. PMID:23870708

  9. Global Status of DDT and Its Alternatives for Use in Vector Control to Prevent Disease

    PubMed Central

    van den Berg, Henk

    2009-01-01

    Objective I review the status of dichlorodiphenyltrichloroethane (DDT), used for disease vector control, along with current evidence on its benefits and risks in relation to the available alternatives. Data sources and extraction Contemporary data on DDT use were largely obtained from questionnaires and reports. I also conducted a Scopus search to retrieve published articles. Data synthesis DDT has been recommended as part of the arsenal of insecticides available for indoor residual spraying until suitable alternatives are available. Approximately 14 countries use DDT for disease control, and several countries are preparing to reintroduce DDT. The effectiveness of DDT depends on local settings and merits close consideration in relation to the alternatives. Concerns about the continued use of DDT are fueled by recent reports of high levels of human exposure associated with indoor spraying amid accumulating evidence on chronic health effects. There are signs that more malaria vectors are becoming resistant to the toxic action of DDT, and that resistance is spreading to new countries. A comprehensive cost assessment of DDT versus its alternatives that takes side effects into account is missing. Effective chemical methods are available as immediate alternatives to DDT, but the choice of insecticide class is limited, and in certain areas the development of resistance is undermining the efficacy of insecticidal tools. New insecticides are not expected in the short term. Nonchemical methods are potentially important, but their effectiveness at program level needs urgent study. Conclusions To reduce reliance on DDT, support is needed for integrated and multipartner strategies of vector control and for the continued development of new technologies. Integrated vector management provides a framework for developing and implementing effective technologies and strategies as sustainable alternatives to reliance on DDT. PMID:20049114

  10. A support vector machine based control application to the experimental three-tank system.

    PubMed

    Iplikci, Serdar

    2010-07-01

    This paper presents a support vector machine (SVM) approach to generalized predictive control (GPC) of multiple-input multiple-output (MIMO) nonlinear systems. The possession of higher generalization potential and at the same time avoidance of getting stuck into the local minima have motivated us to employ SVM algorithms for modeling MIMO systems. Based on the SVM model, detailed and compact formulations for calculating predictions and gradient information, which are used in the computation of the optimal control action, are given in the paper. The proposed MIMO SVM-based GPC method has been verified on an experimental three-tank liquid level control system. Experimental results have shown that the proposed method can handle the control task successfully for different reference trajectories. Moreover, a detailed discussion on data gathering, model selection and effects of the control parameters have been given in this paper. PMID:20417510

  11. The digital autopilot for thrust vector control of the Shuttle Orbital maneuvering system

    NASA Technical Reports Server (NTRS)

    Penchuk, A.; Croopnick, S.

    1982-01-01

    This paper describes the requirements for and the design, development and performance of the digital autopilots (DAPs) for thrust vector control, utilizing the orbital maneuvering system (OMS) of the Space Shuttle Orbiter. The hardware and software requirements which caused the design to assume its current form are described. Also, the design synthesis, which considered rigid body stability margins, bending and slosh stabilization, guidance loop compensation, off-nominal performance and hardware and software limitations is presented. The performance of the OMS control system is summarized utilizing flight data from the first three Space Transportation System (STS) flights.

  12. Application of Lanczos vectors to control design of flexible structures, part 2

    NASA Technical Reports Server (NTRS)

    Craig, Roy R., Jr.; Su, Tzu-Jeng

    1992-01-01

    This report covers the period of the grant from January 1991 until its expiration in June 1992. Together with an Interim Report (Ref. 9), it summarizes the research conducted under NASA Grant NAG9-357 on the topic 'Application of Lanczos Vectors to Control Design of Flexible Structures.' The research concerns various ways to obtain reduced-order mathematical models of complex structures for use in dynamics analysis and in the design of control systems for these structures. This report summarizes the research.

  13. Optical control of retrogradely infected neurons using drug-regulated “TLoop” lentiviral vectors

    PubMed Central

    Cetin, Ali

    2014-01-01

    Many approaches that use viral vectors to deliver transgenes have limited transduction efficiency yet require high levels of transgene expression. In particular, infection via axon terminals is relatively inefficient but is a powerful means of achieving infection of specific neuron types. Combining this with optogenetic approaches requires high gene expression levels that are not typically achieved with nontoxic retrogradely infecting vectors. We generated rabies glycoprotein-pseudotyped lentiviral vectors that use a positive feedback loop composed of a Tet promoter driving both its own tetracycline-dependent transcription activator (tTA) (“TLoop”) and channelrhodopsin-2-YFP (ChR2YFP). We show that TLoop vectors strongly express proteins in a drug-controllable manner in neurons that project to injection sites within the mouse brain. After initial infection, the virus travels retrogradely, stably integrates into the host genome, and expresses gene products. The expression is robust and allows optogenetic studies of neurons projecting to the location of virus injection, as demonstrated by fluorescence-targeted intracellular recordings. ChR2YFP expression did not cause observable signs of toxicity and continued for up to 6 mo after infection. Expression can be reversibly blocked by administration of doxycycline, if necessary, for expression of gene products that might be more toxic. Overall, we present a system that will allow researchers to achieve high levels of gene expression even in the face of inefficient viral transduction. The particular vectors that we demonstrate may enhance efforts to gain a precise understanding of the contributions of specific types of projection neurons to brain function. PMID:24572099

  14. Silver nanoparticles: a possibility for malarial and filarial vector control technology.

    PubMed

    Soni, Namita; Prakash, Soam

    2014-11-01

    Green synthesis technology is one of the rapid, reliable and best routes for the synthesis of silver nanoparticles (AgNPs). There are bioactive compounds with enormous potential in Azadirachta indica (Neem). The extraordinary mosquitoes warrant nanotechnology to integrate with novel molecules. This will be sustainable technology for future. Here, we synthesized AgNPs using aqueous extracts of leaves and bark of Az. indica (Neem). We tested AgNPs as larvicides, pupicides and adulticides against the malaria vector Anopheles stephensi and filariasis vector Culex quinquefasciatus. The results were obtained using UV-visible spectrophotometer and the images were recorded with a transmission electron microscope (TEM). The efficacy tests were then performed at different concentrations varying many hours by probit analysis. The synthesized AgNPs were spherical in shape and with varied sizes (10.47-nm leaf and 19.22-nm bark). The larvae, pupae and adults of filariasis vector C. quinquefasciatus were found to be more susceptible to our AgNPs than the malaria vector An. stephensi. The first and the second instar larvae of C. quinquefasciatus show a mortality rate of 100% after 30 min of exposure. The results against the pupa of C. quinquefasciatus were recorded as LC?? 4 ppm, LC?? 11 ppm and LC?? 13 ppm after 3 h of exposure. In the case of adult mosquitoes, LC?? 1.06 ?L/cm(2), LC?? 2.13 ?L/cm(2) and LC?? 2.4 ?L/cm(2) were obtained after 4 h of exposure. These results suggest that our AgNPs are environment-friendly for controlling malarial and filarial vectors. PMID:25132567

  15. Universal Parameter Measurement and Sensorless Vector Control of Induction and Permanent Magnet Synchronous Motors

    NASA Astrophysics Data System (ADS)

    Yamamoto, Shu; Ara, Takahiro

    Recently, induction motors (IMs) and permanent-magnet synchronous motors (PMSMs) have been used in various industrial drive systems. The features of the hardware device used for controlling the adjustable-speed drive in these motors are almost identical. Despite this, different techniques are generally used for parameter measurement and speed-sensorless control of these motors. If the same technique can be used for parameter measurement and sensorless control, a highly versatile adjustable-speed-drive system can be realized. In this paper, the authors describe a new universal sensorless control technique for both IMs and PMSMs (including salient pole and nonsalient pole machines). A mathematical model applicable for IMs and PMSMs is discussed. Using this model, the authors derive the proposed universal sensorless vector control algorithm on the basis of estimation of the stator flux linkage vector. All the electrical motor parameters are determined by a unified test procedure. The proposed method is implemented on three test machines. The actual driving test results demonstrate the validity of the proposed method.

  16. A distributable, display-device-independent vector graphics system for command and control

    NASA Astrophysics Data System (ADS)

    Bisbey, R., II; Hollingworth, D.

    1980-07-01

    This report documents a distributable, device-independent vector graphics system developed by ISI for the Defense Advanced Research Projects Agency. It describes the system architecture, communications elements, and a phased implementation strategy. The system supports graphics-based command and control applications in distributed computational environments such as the ARPANET. The system has been in use at ISI and at the Naval Ocean Systems Center (NOSC) in the Advanced Command and Control Architectural Testbed (ACCAT) since January 1977. The principal aim of the development effort is the device-independence of the vector graphics. 'Device-independence' means that graphic application programs can be written without regard to the particular display-device on which the output will ultimately be displayed. This system achieves display-device independence by providing the application program with a set of generic, two dimensional vector graphic primitives by which pictures can be described and interacted with at the application level. The particular graphics model used structures pictures as sets of subpictures that are absolute-transformed-segments, as defined by Newman and Sproull.

  17. The role of vector control in stopping the transmission of malaria: threats and opportunities

    PubMed Central

    Hemingway, Janet

    2014-01-01

    Malaria control, and that of other insect borne diseases such as dengue, is heavily dependent on our ability to control the mosquito populations that transmit these diseases. The major push over the last decade to reduce the global burden of malaria has been driven by the distribution of pyrethroid insecticide-treated bednets and an increase in coverage of indoor residual spraying (IRS). This has reduced malaria deaths by a third. Progress towards the goal of reducing this further is threatened by lack of funding and the selection of drug and insecticide resistance. When malaria control was initially scaled up, there was little pyrethroid resistance in the major vectors, today there is no country in Africa where the vectors remain fully susceptible to pyrethroids. The first pyrethroid resistance mechanisms to be selected produced low-level resistance which had little or no operational significance. More recently, metabolically based resistance has been selected, primarily in West Africa, which in some mosquito populations produces more than 1000-fold resistance. As this spreads the effectiveness of pyrethroid-based bednets and IRS will be compromised. New public health insecticides are not readily available. The pipeline of agrochemical insecticides that can be re-purposed for public health dried up 30 years ago when the target product profile for agricultural insecticides shifted from broad spectrum, stable, contact-acting insecticides to narrow spectrum stomach poisons that could be delivered through the plant. A public–private partnership, the Innovative Vector Control Consortium, was established in 2005 to stimulate the development of new public health pesticides. Nine potential new classes of chemistry are in the pipeline, with the intention of developing three into new insecticides. While this has been successfully achieved, it will still take 6–9 years for new insecticides to reach the market. Careful management of the resistance situation in the interim will be needed if current gains in malaria control are not to be reversed. PMID:24821917

  18. The role of vector control in stopping the transmission of malaria: threats and opportunities.

    PubMed

    Hemingway, Janet

    2014-01-01

    Malaria control, and that of other insect borne diseases such as dengue, is heavily dependent on our ability to control the mosquito populations that transmit these diseases. The major push over the last decade to reduce the global burden of malaria has been driven by the distribution of pyrethroid insecticide-treated bednets and an increase in coverage of indoor residual spraying (IRS). This has reduced malaria deaths by a third. Progress towards the goal of reducing this further is threatened by lack of funding and the selection of drug and insecticide resistance. When malaria control was initially scaled up, there was little pyrethroid resistance in the major vectors, today there is no country in Africa where the vectors remain fully susceptible to pyrethroids. The first pyrethroid resistance mechanisms to be selected produced low-level resistance which had little or no operational significance. More recently, metabolically based resistance has been selected, primarily in West Africa, which in some mosquito populations produces more than 1000-fold resistance. As this spreads the effectiveness of pyrethroid-based bednets and IRS will be compromised. New public health insecticides are not readily available. The pipeline of agrochemical insecticides that can be re-purposed for public health dried up 30 years ago when the target product profile for agricultural insecticides shifted from broad spectrum, stable, contact-acting insecticides to narrow spectrum stomach poisons that could be delivered through the plant. A public-private partnership, the Innovative Vector Control Consortium, was established in 2005 to stimulate the development of new public health pesticides. Nine potential new classes of chemistry are in the pipeline, with the intention of developing three into new insecticides. While this has been successfully achieved, it will still take 6-9 years for new insecticides to reach the market. Careful management of the resistance situation in the interim will be needed if current gains in malaria control are not to be reversed. PMID:24821917

  19. A Model Framework to Estimate Impact and Cost of Genetics-Based Sterile Insect Methods for Dengue Vector Control

    PubMed Central

    Alphey, Nina; Alphey, Luke; Bonsall, Michael B.

    2011-01-01

    Vector-borne diseases impose enormous health and economic burdens and additional methods to control vector populations are clearly needed. The Sterile Insect Technique (SIT) has been successful against agricultural pests, but is not in large-scale use for suppressing or eliminating mosquito populations. Genetic RIDL technology (Release of Insects carrying a Dominant Lethal) is a proposed modification that involves releasing insects that are homozygous for a repressible dominant lethal genetic construct rather than being sterilized by irradiation, and could potentially overcome some technical difficulties with the conventional SIT technology. Using the arboviral disease dengue as an example, we combine vector population dynamics and epidemiological models to explore the effect of a program of RIDL releases on disease transmission. We use these to derive a preliminary estimate of the potential cost-effectiveness of vector control by applying estimates of the costs of SIT. We predict that this genetic control strategy could eliminate dengue rapidly from a human community, and at lower expense (approximately US$ 2?30 per case averted) than the direct and indirect costs of disease (mean US$ 86–190 per case of dengue). The theoretical framework has wider potential use; by appropriately adapting or replacing each component of the framework (entomological, epidemiological, vector control bio-economics and health economics), it could be applied to other vector-borne diseases or vector control strategies and extended to include other health interventions. PMID:21998654

  20. Onchocerciasis Transmission in Ghana: Persistence under Different Control Strategies and the Role of the Simuliid Vectors

    PubMed Central

    Lamberton, Poppy H. L.; Cheke, Robert A.; Winskill, Peter; Tirados, Iñaki; Walker, Martin; Osei-Atweneboana, Mike Y.; Biritwum, Nana-Kwadwo; Tetteh-Kumah, Anthony; Boakye, Daniel A.; Wilson, Michael D.; Post, Rory J.; Basañez, María-Gloria

    2015-01-01

    Background The World Health Organization (WHO) aims at eliminating onchocerciasis by 2020 in selected African countries. Current control focuses on community-directed treatment with ivermectin (CDTI). In Ghana, persistent transmission has been reported despite long-term control. We present spatial and temporal patterns of onchocerciasis transmission in relation to ivermectin treatment history. Methodology/Principal Findings Host-seeking and ovipositing blackflies were collected from seven villages in four regions of Ghana with 3–24 years of CDTI at the time of sampling. A total of 16,443 flies was analysed for infection; 5,812 (35.3%) were dissected for parity (26.9% parous). Heads and thoraces of 12,196 flies were dissected for Onchocerca spp. and DNA from 11,122 abdomens was amplified using Onchocerca primers. A total of 463 larvae (0.03 larvae/fly) from 97 (0.6%) infected and 62 (0.4%) infective flies was recorded; 258 abdomens (2.3%) were positive for Onchocerca DNA. Infections (all were O. volvulus) were more likely to be detected in ovipositing flies. Transmission occurred, mostly in the wet season, at Gyankobaa and Bosomase, with transmission potentials of, respectively, 86 and 422 L3/person/month after 3 and 6 years of CDTI. The numbers of L3/1,000 parous flies at these villages were over 100 times the WHO threshold of one L3/1,000 for transmission control. Vector species influenced transmission parameters. At Asubende, the number of L3/1,000 ovipositing flies (1.4, 95% CI = 0–4) also just exceeded the threshold despite extensive vector control and 24 years of ivermectin distribution, but there were no infective larvae in host-seeking flies. Conclusions/Significance Despite repeated ivermectin treatment, evidence of O. volvulus transmission was documented in all seven villages and above the WHO threshold in two. Vector species influences transmission through biting and parous rates and vector competence, and should be included in transmission models. Oviposition traps could augment vector collector methods for monitoring and surveillance. PMID:25897492

  1. Precision Vector Control of a Superconducting RF Cavity driven by an Injection Locked Magnetron

    E-print Network

    Chase, Brian; Cullerton, Ed; Varghese, Philip

    2015-01-01

    The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRF cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.

  2. Precision vector control of a superconducting RF cavity driven by an injection locked magnetron

    SciTech Connect

    Chase, B.; Pasquinelli, R.; Cullerton, E.; Varghese, P.

    2015-03-01

    The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons [1]. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs - compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRF cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.

  3. Precision vector control of a superconducting RF cavity driven by an injection locked magnetron

    DOE PAGESBeta

    Chase, B.; Pasquinelli, R.; Cullerton, E.; Varghese, P.

    2015-03-01

    The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons [1]. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs - compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRFmore »cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.« less

  4. A Gyroless Safehold Control Law using Angular Momentum as an Inertial Reference Vector

    NASA Technical Reports Server (NTRS)

    Stoneking, Eric; Lebsock, Ken

    2008-01-01

    A novel safehold control law was developed for the nadir-pointing Vegetation Canopy Lidar (VCL) spacecraft, necessitated by a challenging combination of constraints. The instrument optics did not have a reclosable cover to protect them from potentially catastrophic damage if they were exposed to direct sunlight. The baseline safehold control law relied on a single-string inertial reference unit. A gyroless safehold law was developed to give a degree of rebustness to gyro failures. Typical safehold solutions were not viable; thermal constraints made spin stabilization unsuitable, and an inertial hold based solely on magnetometer measurements wandered unacceptably during eclipse. The novel approach presented here maintains a momentum bias vector not for gyroscopic stiffness, but to use as an inertial reference direction during eclipse. The control law design is presented. The effect on stability of the rate-deficiency of magnetometer-based rate derivation is assessed. The control law's performance is evaluated by simulation.

  5. A Gyroless Safehold Control Law Using Angular Momentum as an Inertial Reference Vector

    NASA Technical Reports Server (NTRS)

    Stoneking, Eric; Lebsock, Ken

    2008-01-01

    A novel safehold control law was developed for the nadir-pointing Vegetation Canopy Lidar (VCL) spacecraft, necessitated by a challenging combination of constraints. The instrument optics did not have a recloseable cover to protect them form potentially catastrophic damage if they were exposed to direct sunlight. The baseline safehold control law relied on a single-string inertial reference unit. A gyroless safehold law was developed to give a degree of robustness to gyro failures. Typical safehold solutions were not viable; thermal constraints made spin stabilization unsuitable, and an inertial hold based solely on magnetometer measurements wandered unaceptably during eclipse. The novel approach presented here maintains a momentum bias vector not for gyroscopic stiffness, but to use as an inertial reference direction during eclipse. The control law design is presented. The effect on stability of the rank-deficiency of magnetometer-based rate derivation is assessed. The control law's performance is evaluated by simulation.

  6. 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 “egg sinks,” treated sites that exploit conspecific attraction of ovipositing females, but reduce emergence of adult mosquitoes via density-dependent larval competition and late acting insecticide. PMID:21532736

  7. Community-Effectiveness of Temephos for Dengue Vector Control: A Systematic Literature Review.

    PubMed

    George, Leyanna; Lenhart, Audrey; Toledo, Joao; Lazaro, Adhara; Han, Wai Wai; Velayudhan, Raman; Runge Ranzinger, Silvia; Horstick, Olaf

    2015-09-01

    The application of the organophosphate larvicide temephos to water storage containers is one of the most commonly employed dengue vector control methods. This systematic literature review is to the knowledge of the authors the first that aims to assess the community-effectiveness of temephos in controlling both vectors and dengue transmission when delivered either as a single intervention or in combination with other interventions. A comprehensive literature search of 6 databases was performed (PubMed, WHOLIS, GIFT, CDSR, EMBASE, Wiley), grey literature and cross references were also screened for relevant studies. Data were extracted and methodological quality of the studies was assessed independently by two reviewers. 27 studies were included in this systematic review (11 single intervention studies and 16 combined intervention studies). All 11 single intervention studies showed consistently that using temephos led to a reduction in entomological indices. Although 11 of the 16 combined intervention studies showed that temephos application together with other chemical vector control methods also reduced entomological indices, this was either not sustained over time or-as in the five remaining studies--failed to reduce the immature stages. The community-effectiveness of temephos was found to be dependent on factors such as quality of delivery, water turnover rate, type of water, and environmental factors such as organic debris, temperature and exposure to sunlight. Timing of temephos deployment and its need for reapplication, along with behavioural factors such as the reluctance of its application to drinking water, and operational aspects such as cost, supplies, time and labour were further limitations identified in this review. In conclusion, when applied as a single intervention, temephos was found to be effective at suppressing entomological indices, however, the same effect has not been observed when temephos was applied in combination with other interventions. There is no evidence to suggest that temephos use is associated with reductions in dengue transmission. PMID:26371470

  8. Community-Effectiveness of Temephos for Dengue Vector Control: A Systematic Literature Review

    PubMed Central

    George, Leyanna; Lenhart, Audrey; Toledo, Joao; Lazaro, Adhara; Han, Wai Wai; Velayudhan, Raman; Runge Ranzinger, Silvia; Horstick, Olaf

    2015-01-01

    The application of the organophosphate larvicide temephos to water storage containers is one of the most commonly employed dengue vector control methods. This systematic literature review is to the knowledge of the authors the first that aims to assess the community-effectiveness of temephos in controlling both vectors and dengue transmission when delivered either as a single intervention or in combination with other interventions. A comprehensive literature search of 6 databases was performed (PubMed, WHOLIS, GIFT, CDSR, EMBASE, Wiley), grey literature and cross references were also screened for relevant studies. Data were extracted and methodological quality of the studies was assessed independently by two reviewers. 27 studies were included in this systematic review (11 single intervention studies and 16 combined intervention studies). All 11 single intervention studies showed consistently that using temephos led to a reduction in entomological indices. Although 11 of the 16 combined intervention studies showed that temephos application together with other chemical vector control methods also reduced entomological indices, this was either not sustained over time or–as in the five remaining studies—failed to reduce the immature stages. The community-effectiveness of temephos was found to be dependent on factors such as quality of delivery, water turnover rate, type of water, and environmental factors such as organic debris, temperature and exposure to sunlight. Timing of temephos deployment and its need for reapplication, along with behavioural factors such as the reluctance of its application to drinking water, and operational aspects such as cost, supplies, time and labour were further limitations identified in this review. In conclusion, when applied as a single intervention, temephos was found to be effective at suppressing entomological indices, however, the same effect has not been observed when temephos was applied in combination with other interventions. There is no evidence to suggest that temephos use is associated with reductions in dengue transmission. PMID:26371470

  9. Anticipatory Monitoring and Control of Complex Systems using a Fuzzy based Fusion of Support Vector Regressors

    SciTech Connect

    Miltiadis Alamaniotis; Vivek Agarwal

    2014-10-01

    This paper places itself in the realm of anticipatory systems and envisions monitoring and control methods being capable of making predictions over system critical parameters. Anticipatory systems allow intelligent control of complex systems by predicting their future state. In the current work, an intelligent model aimed at implementing anticipatory monitoring and control in energy industry is presented and tested. More particularly, a set of support vector regressors (SVRs) are trained using both historical and observed data. The trained SVRs are used to predict the future value of the system based on current operational system parameter. The predicted values are then inputted to a fuzzy logic based module where the values are fused to obtain a single value, i.e., final system output prediction. The methodology is tested on real turbine degradation datasets. The outcome of the approach presented in this paper highlights the superiority over single support vector regressors. In addition, it is shown that appropriate selection of fuzzy sets and fuzzy rules plays an important role in improving system performance.

  10. Lentiviral vector system for coordinated constitutive and drug controlled tetracycline-regulated gene co-expression.

    PubMed

    Stahlhut, Maike; Schwarzer, Adrian; Eder, Matthias; Yang, Min; Li, Zhixiong; Morgan, Michael; Schambach, Axel; Kustikova, Olga S

    2015-09-01

    Constitutive co-expression of cooperating transgenes using retroviral integrating vectors is frequently used for genetic modification of different cell types to establish therapeutic or cancer models. However, such approaches are unable to dissect the influence of dose, order and reversibility of transgene expression on the fate of newly developed therapeutic/malignant phenotypes. We present a modular lentiviral vector system, which provides expression of constitutive and inducible components. To demonstrate its functionality, we constitutively expressed the well-described transcription factor Meis1 followed by inducible co-expression of collaborating partner Hoxa9 under the control of tetracycline responsive promoters in murine fibroblasts and primary hematopoietic progenitor cells (HPCs). Fluorescent markers to track transgene co-expression revealed tightly controlled, efficiently inducible and reversible but cell type dependent gene transfer over time. We demonstrated dose-dependent blockade of myeloid differentiation when both Meis1/Hoxa9 were concomitantly overexpressed in primary HPCs in vitro, but the absence of the transformed phenotype in non-induced samples or when Hoxa9 expression was down-regulated. This system combines the advantages of lentiviral gene transfer and the opportunity for drug-controlled co-expression of multiple transgenes to dissect, among others, gene networks governing complex cell behavior, such as proto-oncogene dose-dependent leukemogenic pathways or collaborating mechanisms of genes enhancing competitive fitness of hematopoietic cells. PMID:26113075

  11. Solid rocket booster thrust vector control V-2 off-nominal testing

    NASA Technical Reports Server (NTRS)

    Pagan, B.

    1981-01-01

    The results of the V-2 off nominal test sequence performed on the space shuttle solid rocket booster thrust vector control (SRB TVC) system are reported. The TVC subsystem was subjected to 19 off nominal test conditions. The test sequence consisted of: 8 burp starts, 30 hot firings, 14 GN2 spin tests, and 3 servicing passive system tests. It is concluded that the TVC subsystem operated nominally in response to the given commands and test conditions. Test objectives, detail results, and data are included.

  12. Vector Control and Foliar Nutrition for Management of Huanglongbing in Florida Citrus Philip A. Stansly, H. Alejandro Arevalo, Jawwad A. Qureshi, Moneen M. Jones, Katherine

    E-print Network

    Ma, Lena

    7.4 Vector Control and Foliar Nutrition for Management of Huanglongbing in Florida Citrus Philip A, And Fritz M. Roka Huanglongbing (HLB) or citrus greening is a bacterial disease vectored by the Asian citrus

  13. Area-wide biological control of disease vectors and agents affecting wildlife.

    PubMed

    Reichard, R E

    2002-04-01

    Two examples of area-wide programmes, employing the sterile insect technique (SIT), which have eradicated a parasite and a disease vector common to domestic and wild animals are described. New World screwworm (NWS), Cochliomyia hominivorax, caused significant morbidity and mortality of livestock and wild mammals in tropical and subtropical areas of America before eradication was achieved in North America using the SIT and other components of an integrated pest management (IPM) programme. Movement of wild as well as domestic animals from an area which is infested with screwworm to a free area requires prophylactic treatment. Tsetse fly-borne trypanosomosis has an immense influence on the distribution of people and livestock in Africa. The immunotolerance of wildlife to the parasites is an important factor in maintaining some areas livestock free as wildlife refuges. Slaughter has ceased of wild hoofstock species considered to be disease reservoirs for control purposes. The SIT, combined with other IPM measures, has resulted in the eradication of the tsetse fly and trypanosomosis from Zanzibar. Other programmes in Africa are underway. Microbial 'biopesticides' have also been employed successfully against plant insect pests and some vectors of human disease. It seems likely that for the immediate future, wildlife may benefit from area-wide biological control programmes, intended mainly to protect humans and/or domestic animals. PMID:11974628

  14. Can vector control play a useful supplementary role against bancroftian filariasis?

    PubMed Central

    Maxwell, C. A.; Mohammed, K.; Kisumku, U.; Curtis, C. F.

    1999-01-01

    A single campaign of mass treatment for bancroftian filariasis with diethylcarbamazine (DEC) in Makunduchi, a town in Zanzibar, United Republic of Tanzania, combined with elimination of mosquito breeding in pit latrines with polystyrene beads was followed by a progressive decline over a 5-year period in the microfilarial rate from 49% to 3%. Evidence that vector control had contributed to this long-term decline was obtained by comparison with another town, Moga, where a DEC campaign was used without vector control and where resurgence of microfilariae could be observed 3-6 years after the campaign. In Zanzibar town, treatment of 3844 wet pit latrines and cesspits with polystyrene beads reduced the adult mosquito population in houses by about 65%. Supplementary treatment of open drains and marshes with Bacillus sphaericus produced little or no additional reduction compared to a sector of the town where only pit treatment with polystyrene was carried out. The cost and effort of achieving the 65% reduction in mosquito population could hardly be justified for its impact on filariasis alone, but its noticeable impact on biting nuisance might help to gain community support for an integrated programme. PMID:10083712

  15. Substituted 2-phenylimidazopyridines: a new class of drug leads for human African trypanosomiasis.

    PubMed

    Tatipaka, Hari Babu; Gillespie, J Robert; Chatterjee, Arnab K; Norcross, Neil R; Hulverson, Matthew A; Ranade, Ranae M; Nagendar, Pendem; Creason, Sharon A; McQueen, Joshua; Duster, Nicole A; Nagle, Advait; Supek, Frantisek; Molteni, Valentina; Wenzler, Tanja; Brun, Reto; Glynne, Richard; Buckner, Frederick S; Gelb, Michael H

    2014-02-13

    A phenotypic screen of a compound library for antiparasitic activity on Trypanosoma brucei, the causative agent of human African trypanosomiasis, led to the identification of substituted 2-(3-aminophenyl)oxazolopyridines as a starting point for hit-to-lead medicinal chemistry. A total of 110 analogues were prepared, which led to the identification of 64, a substituted 2-(3-aminophenyl)imidazopyridine. This compound showed antiparasitic activity in vitro with an EC50 of 2 nM and displayed reasonable druglike properties when tested in a number of in vitro assays. The compound was orally bioavailable and displayed good plasma and brain exposure in mice. Compound 64 cured mice infected with Trypanosoma brucei when dosed orally down to 2.5 mg/kg. Given its potent antiparasitic properties and its ease of synthesis, compound 64 represents a new lead for the development of drugs to treat human African trypanosomiasis. PMID:24354316

  16. Design of Instrument Control Software for Solar Vector Magnetograph at Udaipur Solar Observatory

    NASA Astrophysics Data System (ADS)

    Gosain, Sanjay; Venkatakrishnan, P.; Venugopalan, K.

    2004-04-01

    A magnetograph is an instrument which makes measurement of solar magnetic field by measuring Zeeman induced polarization in solar spectral lines. In a typical filter based magnetograph there are three main modules namely, polarimeter, narrow-band spectrometer (filter), and imager(CCD camera). For a successful operation of magnetograph it is essential that these modules work in synchronization with each other. Here, we describe the design of instrument control system implemented for the Solar Vector Magnetograph under development at Udaipur Solar Observatory. The control software is written in Visual Basic and exploits the Component Object Model (COM) components for a fast and flexible application development. The user can interact with the instrument modules through a Graphical User Interface (GUI) and can program the sequence of magnetograph operations. The integration of Interactive Data Language (IDL) ActiveX components in the interface provides a powerful tool for online visualization, analysis and processing of images.

  17. Framework for rapid assessment and adoption of new vector control tools.

    PubMed

    Vontas, John; Moore, Sarah; Kleinschmidt, Immo; Ranson, Hilary; Lindsay, Steve; Lengeler, Christian; Hamon, Nicholas; McLean, Tom; Hemingway, Janet

    2014-04-01

    Evidence-informed health policy making is reliant on systematic access to, and appraisal of, the best available research evidence. This review suggests a strategy to improve the speed at which evidence is gathered on new vector control tools (VCTs) using a framework based on measurements of the vectorial capacity of an insect population to transmit disease. We explore links between indicators of VCT efficacy measurable in small-scale experiments that are relevant to entomological and epidemiological parameters measurable only in large-scale proof-of-concept randomised control trials (RCTs). We hypothesise that once RCTs establish links between entomological and epidemiological indicators then rapid evaluation of new products within the same product category may be conducted through smaller scale experiments without repetition of lengthy and expensive RCTs. PMID:24657042

  18. Current status of kala-azar and vector control in China.

    PubMed Central

    Guan, L. R.

    1991-01-01

    Kala-azar, which was prevalent in the vast area of China that lies to the north of the Yangtze River from the 1920s to the 1950s, is now effectively under control as a result of strenuous intervention since the founding of the People's Republic of China in 1949. Apart from 15-20 new cases that occur annually in the Keshi plain, Xinjiang Autonomous Region, the achievements of control practised in other former endemic areas in the plains have been significant and consolidated. In the mountainous areas in north-west China, where the vector, Phlebotomus chinensis, is abundant and canine visceral leishmaniasis is common, there are still sporadic cases of kala-azar. Also, in recent years, new infections have often occurred in the deserts of Xinjiang and western Inner Mongolia, although the reservoir of the infection has not been identified. PMID:1959161

  19. Optimization of Control Strategies for Non-Domiciliated Triatoma dimidiata, Chagas Disease Vector in the Yucatán Peninsula, Mexico

    PubMed Central

    Barbu, Corentin; Dumonteil, Eric; Gourbière, Sébastien

    2009-01-01

    Background Chagas disease is the most important vector-borne disease in Latin America. Regional initiatives based on residual insecticide spraying have successfully controlled domiciliated vectors in many regions. Non-domiciliated vectors remain responsible for a significant transmission risk, and their control is now a key challenge for disease control. Methodology/Principal Findings A mathematical model was developed to predict the temporal variations in abundance of non-domiciliated vectors inside houses. Demographic parameters were estimated by fitting the model to two years of field data from the Yucatan peninsula, Mexico. The predictive value of the model was tested on an independent data set before simulations examined the efficacy of control strategies based on residual insecticide spraying, insect screens, and bednets. The model accurately fitted and predicted field data in the absence and presence of insecticide spraying. Pyrethroid spraying was found effective when 50 mg/m2 were applied yearly within a two-month period matching the immigration season. The >80% reduction in bug abundance was not improved by larger doses or more frequent interventions, and it decreased drastically for different timing and lower frequencies of intervention. Alternatively, the use of insect screens consistently reduced bug abundance proportionally to the reduction of the vector immigration rate. Conclusion/Significance Control of non-domiciliated vectors can hardly be achieved by insecticide spraying, because it would require yearly application and an accurate understanding of the temporal pattern of immigration. Insect screens appear to offer an effective and sustainable alternative, which may be part of multi-disease interventions for the integrated control of neglected vector-borne diseases. PMID:19365542

  20. Thrust-vector control of a three-axis stabilized upper-stage rocket with fuel slosh dynamics

    NASA Astrophysics Data System (ADS)

    Rubio Hervas, Jaime; Reyhanoglu, Mahmut

    2014-05-01

    This paper studies the thrust vector control problem for an upper-stage rocket with fuel slosh dynamics. The dynamics of a three-axis stabilized spacecraft with a single partially-filled fuel tank are formulated and the sloshing propellant is modeled as a multi-mass-spring system, where the oscillation frequencies of the mass-spring elements represent the prominent sloshing modes. The equations of motion are expressed in terms of the three-dimensional spacecraft translational velocity vector, the attitude, the angular velocity, and the internal coordinates representing the slosh modes. A Lyapunov-based nonlinear feedback control law is proposed to control the translational velocity vector and the attitude of the spacecraft, while attenuating the sloshing modes characterizing the internal dynamics. A simulation example is included to illustrate the effectiveness of the control law.

  1. Eco-bio-social research on community-based approaches for Chagas disease vector control in Latin America.

    PubMed

    Gürtler, Ricardo E; Yadon, Zaida E

    2015-02-01

    This article provides an overview of three research projects which designed and implemented innovative interventions for Chagas disease vector control in Bolivia, Guatemala and Mexico. The research initiative was based on sound principles of community-based ecosystem management (ecohealth), integrated vector management, and interdisciplinary analysis. The initial situational analysis achieved a better understanding of ecological, biological and social determinants of domestic infestation. The key factors identified included: housing quality; type of peridomestic habitats; presence and abundance of domestic dogs, chickens and synanthropic rodents; proximity to public lights; location in the periphery of the village. In Bolivia, plastering of mud walls with appropriate local materials and regular cleaning of beds and of clothes next to the walls, substantially decreased domestic infestation and abundance of the insect vector Triatoma infestans. The Guatemalan project revealed close links between house infestation by rodents and Triatoma dimidiata, and vector infection with Trypanosoma cruzi. A novel community-operated rodent control program significantly reduced rodent infestation and bug infection. In Mexico, large-scale implementation of window screens translated into promising reductions in domestic infestation. A multi-pronged approach including community mobilisation and empowerment, intersectoral cooperation and adhesion to integrated vector management principles may be the key to sustainable vector and disease control in the affected regions. PMID:25604759

  2. Eco-bio-social research on community-based approaches for Chagas disease vector control in Latin America

    PubMed Central

    Gürtler, Ricardo E.; Yadon, Zaida E.

    2015-01-01

    This article provides an overview of three research projects which designed and implemented innovative interventions for Chagas disease vector control in Bolivia, Guatemala and Mexico. The research initiative was based on sound principles of community-based ecosystem management (ecohealth), integrated vector management, and interdisciplinary analysis. The initial situational analysis achieved a better understanding of ecological, biological and social determinants of domestic infestation. The key factors identified included: housing quality; type of peridomestic habitats; presence and abundance of domestic dogs, chickens and synanthropic rodents; proximity to public lights; location in the periphery of the village. In Bolivia, plastering of mud walls with appropriate local materials and regular cleaning of beds and of clothes next to the walls, substantially decreased domestic infestation and abundance of the insect vector Triatoma infestans. The Guatemalan project revealed close links between house infestation by rodents and Triatoma dimidiata, and vector infection with Trypanosoma cruzi. A novel community-operated rodent control program significantly reduced rodent infestation and bug infection. In Mexico, large-scale implementation of window screens translated into promising reductions in domestic infestation. A multi-pronged approach including community mobilisation and empowerment, intersectoral cooperation and adhesion to integrated vector management principles may be the key to sustainable vector and disease control in the affected regions. PMID:25604759

  3. A novel biopesticide PONNEEM to control human vector mosquitoes Anopheles stephensi L. and Culex quinquefasciatus Say.

    PubMed

    Maheswaran, Rajan; Ignacimuthu, Savarimuthu

    2015-09-01

    Organophosphate pesticides are widely used in vector mosquito management and agricultural pest management. These chemicals enter into natural water bodies and soil and cause hazards to the environment. The objective of this study was to prepare a natural pesticide which will not harm the environment and yet control vector mosquitoes. PONNEEM, a novel biopesticide, patented and prepared from the oils of Azadirachta indica and Pongamia glabra, was tested against Anopheles stephensi and Culex quinquefasciatus. One hundred percent larvicidal and ovicidal activities were observed at 0.1-ppm concentration of PONNEEM against the two mosquito species under laboratory and sunlight conditions up to 12 months from the date of manufacture. Very high oviposition reduction of 26.46 and 32.16 % is also recorded. Reductions in ?-esterase level (0.0818?±?0.340 and 0.2188?±?0.003), ?-esterase level (0.0866?±?0.026 and 0.0398?±?0.010 ?g naphthol produced/min/mg larval protein), glutathione S-transferase enzyme (14.2571?±?0.51 and 15.3326?±?0.51 ?mol/min/mg larval protein) and total protein levels (0.0390?±?0.008 and 0.1975?±?0.029 mg/individual larva in treated groups of A. stephensi and C. quinquefasciatus at 0.1-ppm concentration, respectively. The non-target organisms such as Gambusia affinis and Diplonychus indicus were not affected. Biopesticides are good alternatives to synthetic pesticides. PONNEEM can be effectively used for the management of human vector mosquitoes. Since it has a biodegradable nature and does not alter the environmental condition of water and soil. PMID:25929457

  4. USDA-ARS-CMAVE Pesticide Research for the DoD: A Needs-Based Program for Vector Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite existing measures to prevent and control arthropod-borne diseases in military units, these diseases continue to be serious threats to deployed troops. Due to a shrinking list of safe, cost-effective pesticides for control of disease vectors, new and improved toxicants and methods for deliver...

  5. Tsetse Control and Gambian Sleeping Sickness; Implications for Control Strategy

    PubMed Central

    Kovacic, Vanja; Mangwiro, T. N. Clement; Vale, Glyn A.; Hastings, Ian; Solano, Philippe; Lehane, Michael J.; Torr, Steve J.

    2015-01-01

    Background Gambian sleeping sickness (human African trypanosomiasis, HAT) outbreaks are brought under control by case detection and treatment although it is recognised that this typically only reaches about 75% of the population. Vector control is capable of completely interrupting HAT transmission but is not used because it is considered too expensive and difficult to organise in resource-poor settings. We conducted a full scale field trial of a refined vector control technology to determine its utility in control of Gambian HAT. Methods and Findings The major vector of Gambian HAT is the tsetse fly Glossina fuscipes which lives in the humid zone immediately adjacent to water bodies. From a series of preliminary trials we determined the number of tiny targets required to reduce G. fuscipes populations by more than 90%. Using these data for model calibration we predicted we needed a target density of 20 per linear km of river in riverine savannah to achieve >90% tsetse control. We then carried out a full scale, 500 km2 field trial covering two HAT foci in Northern Uganda to determine the efficacy of tiny targets (overall target density 5.7/km2). In 12 months, tsetse populations declined by more than 90%. As a guide we used a published HAT transmission model and calculated that a 72% reduction in tsetse population is required to stop transmission in those settings. Interpretation The Ugandan census suggests population density in the HAT foci is approximately 500 per km2. The estimated cost for a single round of active case detection (excluding treatment), covering 80% of the population, is US$433,333 (WHO figures). One year of vector control organised within the country, which can completely stop HAT transmission, would cost US$42,700. The case for adding this method of vector control to case detection and treatment is strong. We outline how such a component could be organised. PMID:26267814

  6. Contrasting Population Structures of Two Vectors of African Trypanosomoses in Burkina Faso: Consequences for Control

    PubMed Central

    Ravel, Sophie; Vreysen, Marc J. B.; Domagni, Kouadjo T.; Causse, Sandrine; Solano, Philippe; de Meeûs, Thierry

    2011-01-01

    Background African animal trypanosomosis is a major obstacle to the development of more efficient and sustainable livestock production systems in West Africa. Riverine tsetse species such as Glossina palpalis gambiensis Vanderplank and Glossina tachinoides Westwood are the major vectors. A wide variety of control tactics is available to manage these vectors, but their removal will in most cases only be sustainable if the control effort is targeting an entire tsetse population within a circumscribed area. Methodology/Principal Findings In the present study, genetic variation at microsatellite DNA loci was used to examine the population structure of G. p. gambiensis and G. tachinoides inhabiting four adjacent river basins in Burkina Faso, i.e. the Mouhoun, the Comoé, the Niger and the Sissili River Basins. Isolation by distance was significant for both species across river basins, and dispersal of G. tachinoides was ?3 times higher than that of G. p. gambiensis. Thus, the data presented indicate that no strong barriers to gene flow exists between riverine tsetse populations in adjacent river basins, especially so for G. tachinoides. Conclusions/Significance Therefore, potential re-invasion of flies from adjacent river basins will have to be prevented by establishing buffer zones between the Mouhoun and the other river basin(s), in the framework of the PATTEC (Pan African Tsetse and Trypanosomosis Eradication Campaign) eradication project that is presently targeting the northern part of the Mouhoun River Basin. We argue that these genetic analyses should always be part of the baseline data collection before any tsetse control project is initiated. PMID:21738812

  7. Potential of native Beauveria pseudobassiana strain for biological control of Pine Wood Nematode vector Monochamus galloprovincialis.

    PubMed

    Álvarez-Baz, G; Fernández-Bravo, M; Pajares, J; Quesada-Moraga, E

    2015-11-01

    Three entomopathogenic fungal strains, Isaria farinosa (Holmsk.) Fr., Lecanicillium attenuatum (Zare & W. Games) and Beauveria pseudobassiana (Bals.) Vuill. were isolated in Spain from naturally infected Monochamus galloprovincialis (Olivier) (Coleoptera: Cerambycidae), the European vector of Pine Wilt Disease (PWD). This is the first time that these entomopathogenic fungi have been isolated from M. galloprovincialis beetles. Assays showed the B. pseudobassiana EABps 11/01-Mg strain to be highly virulent against the pine sawyer. Horizontal and vertical transmission were assessed for both aqueous (1×10(8)conidia/ml) and dry (4.25×10(9)conidia/g) conidial formulations. Evidence of horizontal or vertical transmission was not found when insects were inoculated with the aqueous conidial suspension. However, when dry conidia were applied, 100% of the horizontally-infected insects died and their average survival times (AST) were significantly reduced (from 21.10 and 25.00days in controls to 10.40 and 10.00days in infected males and females, respectively). Compared to control females, numbers of egg-laying wounds, eggs laid, live larvae after 5days and larvae entering the xylem after 6months were significantly reduced in both inoculated females and clean females that had mated with inoculated males, pointing to horizontally-induced reduction of progeny. These results validate the potential of the isolated B. pseudobassiana strain as an important natural population regulator. Through auto-dissemination techniques, it could be used for the integrated control of Pine Wood Nematode vectors and constitute a new tool for Pine Wilt Disease management. PMID:26283466

  8. Major QTLs Control Resistance to Rice Hoja Blanca Virus and Its Vector Tagosodes orizicolus

    PubMed Central

    Romero, Luz E.; Lozano, Ivan; Garavito, Andrea; Carabali, Silvio J.; Triana, Monica; Villareal, Natalia; Reyes, Luis; Duque, Myriam C.; Martinez, César P.; Calvert, Lee; Lorieux, Mathias

    2013-01-01

    Rice hoja blanca (white leaf) disease can cause severe yield losses in rice in the Americas. The disease is caused by the rice hoja blanca virus (RHBV), which is transmitted by the planthopper vector Tagosodes orizicolus. Because classical breeding schemes for this disease rely on expensive, time-consuming screenings, there is a need for alternatives such as marker-aided selection. The varieties Fedearroz 2000 and Fedearroz 50, which are resistant to RHBV and to the feeding damage caused by T. orizicolus, were crossed with the susceptible line WC366 to produce segregating F2:3 populations. The F3 families were scored for their resistance level to RHBV and T. orizicolus. The F2:3 lines of both crosses were genotyped using microsatellite markers. One major QTL on the short arm of chromosome 4 was identified for resistance to RHBV in the two populations. Two major QTL on chromosomes 5 and 7 were identified for resistance to T. orizicolus in the Fd2000 × WC366 and Fd50 × WC366 crosses, respectively. This comparative study using two distinct rice populations allowed for a better understanding of how the resistance to RHBV and its vector are controlled genetically. Simple marker-aided breeding schemes based on QTL information can be designed to improve rice germplasm to reduce losses caused by this important disease. PMID:24240781

  9. Test stand for precise measurement of impulse and thrust vector of small attitude control jets

    NASA Technical Reports Server (NTRS)

    Woodruff, J. R.; Chisel, D. M.

    1973-01-01

    A test stand which accurately measures the impulse bit and thrust vector of reaction jet thrusters used in the attitude control system of space vehicles has been developed. It can be used to measure, in a vacuum or ambient environment, both impulse and thrust vector of reaction jet thrusters using hydrazine or inert gas propellants. The ballistic pendulum configuration was selected because of its accuracy, simplicity, and versatility. The pendulum is mounted on flexure pivots rotating about a vertical axis at the center of its mass. The test stand has the following measurement capabilities: impulse of 0.00004 to 4.4 N-sec (0.00001 to 1.0 lb-sec) with a pulse duration of 0.5 msec to 1 sec; static thrust of 0.22 to 22 N (0.05 to 5 lb) with a 5 percent resolution; and thrust angle alinement of 0.22 to 22 N (0.05 to 5 lb) thrusters with 0.01 deg accuracy.

  10. Effectiveness of Large-Scale Chagas Disease Vector Control Program in Nicaragua by Residual Insecticide Spraying Against Triatoma dimidiata.

    PubMed

    Yoshioka, Kota; Nakamura, Jiro; Pérez, Byron; Tercero, Doribel; Pérez, Lenin; Tabaru, Yuichiro

    2015-12-01

    Chagas disease is one of the most serious health problems in Latin America. Because the disease is transmitted mainly by triatomine vectors, a three-phase vector control strategy was used to reduce its vector-borne transmission. In Nicaragua, we implemented an indoor insecticide spraying program in five northern departments to reduce house infestation by Triatoma dimidiata. The spraying program was performed in two rounds. After each round, we conducted entomological evaluation to compare the vector infestation level before and after spraying. A total of 66,200 and 44,683 houses were sprayed in the first and second spraying rounds, respectively. The entomological evaluation showed that the proportion of houses infested by T. dimidiata was reduced from 17.0% to 3.0% after the first spraying, which was statistically significant (P < 0.0001). However, the second spraying round did not demonstrate clear effectiveness. Space-time analysis revealed that reinfestation of T. dimidiata is more likely to occur in clusters where the pre-spray infestation level is high. Here we discuss how large-scale insecticide spraying is neither effective nor affordable when T. dimidiata is widely distributed at low infestation levels. Further challenges involve research on T. dimidiata reinfestation, diversification of vector control strategies, and implementation of sustainable vector surveillance. PMID:26416118

  11. Biology and control of Taeniorhynchus (Mansonioides) uniformis Theobald, the chief vector of rural filariasis in Ceylon.

    PubMed

    ANTONIPULLE, P; DAVID, H V; KARUNARATNE, M D

    1958-01-01

    Residual spraying of DDT for the control of Taeniorhynchus (Mansonioides) uniformis, the mosquito vector of rural filariasis in Ceylon, was carried out in Induruwa, a village on the west coast of the island. The results showed that the insecticide retained its effectiveness for a period of 4-6 months.During the course of this investigation, various observations were made on the behaviour of T. (M.) uniformis. Its host plants, day-time resting-places, feeding habits, and response to light-particularly moonlight-were recorded. An increase in T. (M.) uniformis prevalence was observed to coincide with the onset of the north-east and south-west monsoons, when the paddy-fields are inundated and become overgrown with Isachne australis, the most common aquatic plant in the area and a favourite breeding-place of this mosquito species. PMID:13585075

  12. Controlling wave-vector of propagating surface plasmon polaritons on single-crystalline gold nanoplates

    PubMed Central

    Luo, Si; Yang, Hangbo; Yang, Yuanqing; Zhao, Ding; Chen, Xingxing; Qiu, Min; Li, Qiang

    2015-01-01

    Surface plasmon polaritons (SPPs) propagating at metal nanostructures play an important role in breaking the diffraction limit. Chemically synthesized single-crystalline metal nanoplates with atomically flat surfaces provide favorable features compared with traditional polycrystalline metal films. The excitation and propagation of leaky SPPs on micrometer sized (10–20??m) and thin (30?nm) gold nanoplates are investigated utilizing leakage radiation microscopy. By varying polarization and excitation positions of incident light on apexes of nanoplates, wave-vector (including propagation constant and propagation direction) distributions of leaky SPPs in Fourier planes can be controlled, indicating tunable SPP propagation. These results hold promise for potential development of chemically synthesized single-crystalline metal nanoplates as plasmonic platforms in future applications. PMID:26302955

  13. PAB3D Simulations of a Nozzle with Fluidic Injection for Yaw Thrust-Vector Control

    NASA Technical Reports Server (NTRS)

    Deere, Karen A.

    1998-01-01

    An experimental and computational study was conducted on an exhaust nozzle with fluidic injection for yaw thrust-vector control. The nozzle concept was tested experimentally in the NASA Langley Jet Exit Test Facility (JETF) at nozzle pressure ratios up to 4 and secondary fluidic injection flow rates up to 15 percent of the primary flow rate. Although many injection-port geometries and two nozzle planforms (symmetric and asymmetric) were tested experimentally, this paper focuses on the computational results of the more successful asymmetric planform with a slot injection port. This nozzle concept was simulated with the Navier-Stokes flow solver, PAB3D, invoking the Shih, Zhu, and Lumley algebraic Reynolds stress turbulence model (ASM) at nozzle pressure ratios (NPRs) of 2,3, and 4 with secondary to primary injection flow rates (w(sub s)/w(sub p)) of 0, 2, 7 and 10 percent.

  14. Implementation of the Orbital Maneuvering Systems Engine and Thrust Vector Control for the European Service Module

    NASA Technical Reports Server (NTRS)

    Millard, Jon

    2014-01-01

    The European Space Agency (ESA) has entered into a partnership with the National Aeronautics and Space Administration (NASA) to develop and provide the Service Module (SM) for the Orion Multipurpose Crew Vehicle (MPCV) Program. The European Service Module (ESM) will provide main engine thrust by utilizing the Space Shuttle Program Orbital Maneuvering System Engine (OMS-E). Thrust Vector Control (TVC) of the OMS-E will be provided by the Orbital Maneuvering System (OMS) TVC, also used during the Space Shuttle Program. NASA will be providing the OMS-E and OMS TVC to ESA as Government Furnished Equipment (GFE) to integrate into the ESM. This presentation will describe the OMS-E and OMS TVC and discuss the implementation of the hardware for the ESM.

  15. Target product profile choices for intra-domiciliary malaria vector control pesticide products: repel or kill?

    PubMed Central

    2011-01-01

    Background The most common pesticide products for controlling malaria-transmitting mosquitoes combine two distinct modes of action: 1) conventional insecticidal activity which kills mosquitoes exposed to the pesticide and 2) deterrence of mosquitoes away from protected humans. While deterrence enhances personal or household protection of long-lasting insecticidal nets and indoor residual sprays, it may also attenuate or even reverse communal protection if it diverts mosquitoes to non-users rather than killing them outright. Methods A process-explicit model of malaria transmission is described which captures the sequential interaction between deterrent and toxic actions of vector control pesticides and accounts for the distinctive impacts of toxic activities which kill mosquitoes before or after they have fed upon the occupant of a covered house or sleeping space. Results Increasing deterrency increases personal protection but consistently reduces communal protection because deterrent sub-lethal exposure inevitably reduces the proportion subsequently exposed to higher lethal doses. If the high coverage targets of the World Health Organization are achieved, purely toxic products with no deterrence are predicted to generally provide superior protection to non-users and even users, especially where vectors feed exclusively on humans and a substantial amount of transmission occurs outdoors. Remarkably, this is even the case if that product confers no personal protection and only kills mosquitoes after they have fed. Conclusions Products with purely mosquito-toxic profiles may, therefore, be preferable for programmes with universal coverage targets, rather than those with equivalent toxicity but which also have higher deterrence. However, if purely mosquito-toxic products confer little personal protection because they do not deter mosquitoes and only kill them after they have fed, then they will require aggressive "catch up" campaigns, with behaviour change communication strategies that emphasize the communal nature of protection, to achieve high coverage rapidly. PMID:21798023

  16. 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. PMID:23318235

  17. High effective coverage of vector control interventions in children after achieving low malaria transmission in Zanzibar, Tanzania

    PubMed Central

    2013-01-01

    Background Formerly a high malaria transmission area, Zanzibar is now targeting malaria elimination. A major challenge is to avoid resurgence of malaria, the success of which includes maintaining high effective coverage of vector control interventions such as bed nets and indoor residual spraying (IRS). In this study, caretakers' continued use of preventive measures for their children is evaluated, following a sharp reduction in malaria transmission. Methods A cross-sectional community-based survey was conducted in June 2009 in North A and Micheweni districts in Zanzibar. Households were randomly selected using two-stage cluster sampling. Interviews were conducted with 560 caretakers of under-five-year old children, who were asked about perceptions on the malaria situation, vector control, household assets, and intention for continued use of vector control as malaria burden further decreases. Results Effective coverage of vector control interventions for under-five children remains high, although most caretakers (65%; 363/560) did not perceive malaria as presently being a major health issue. Seventy percent (447/643) of the under-five children slept under a long-lasting insecticidal net (LLIN) and 94% (607/643) were living in houses targeted with IRS. In total, 98% (628/643) of the children were covered by at least one of the vector control interventions. Seasonal bed-net use for children was reported by 25% (125/508) of caretakers of children who used bed nets. A high proportion of caretakers (95%; 500/524) stated that they intended to continue using preventive measures for their under-five children as malaria burden further reduces. Malaria risk perceptions and different perceptions of vector control were not found to be significantly associated with LLIN effective coverage. Conclusions While the majority of caretakers felt that malaria had been reduced in Zanzibar, effective coverage of vector control interventions remained high. Caretakers appreciated the interventions and recognized the value of sustaining their use. Thus, sustaining high effective coverage of vector control interventions, which is crucial for reaching malaria elimination in Zanzibar, can be achieved by maintaining effective delivery of these interventions. PMID:23360479

  18. Results of solar electric thrust vector control system design, development and tests

    NASA Technical Reports Server (NTRS)

    Fleischer, G. E.

    1973-01-01

    Efforts to develop and test a thrust vector control system TVCS for a solar-energy-powered ion engine array are described. The results of solar electric propulsion system technology (SEPST) III real-time tests of present versions of TVCS hardware in combination with computer-simulated attitude dynamics of a solar electric multi-mission spacecraft (SEMMS) Phase A-type spacecraft configuration are summarized. Work on an improved solar electric TVCS, based on the use of a state estimator, is described. SEPST III tests of TVCS hardware have generally proved successful and dynamic response of the system is close to predictions. It appears that, if TVCS electronic hardware can be effectively replaced by control computer software, a significant advantage in control capability and flexibility can be gained in future developmental testing, with practical implications for flight systems as well. Finally, it is concluded from computer simulations that TVCS stabilization using rate estimation promises a substantial performance improvement over the present design.

  19. Proposed use of spatial mortality assessments as part of the pesticide evaluation scheme for vector control

    PubMed Central

    2013-01-01

    Background The WHO Pesticide Evaluation Scheme to evaluate the efficacy of insecticides does not include the testing of a lethal effect at a distance. A tool was developed to evaluate the spatial mortality of an insecticide product against adult mosquitoes at a distance under laboratory and field conditions. Operational implications are discussed. Methods Insecticide paint, Inesfly 5A IGR™, containing two organophosphates (OPs): chlorpyrifos and diazinon, and one insect growth regulator (IGR): pyriproxyfen, was the product tested. Laboratory tests were performed using “distance boxes” with surfaces treated with one layer of control or insecticide paint at a dose of 1 kg/6 sq m. Field tests were conducted up to 12 months in six experimental huts randomly allocated to control or one or two layers of insecticide paint at 1 kg/6 sq m. All distance tests were performed using reference-susceptible strains of Anopheles gambiae and Culex quinquefasciatus left overnight at a distance of 1 m from control or treated surfaces. Results After an overnight exposition at distances of 1 m, field and laboratory evaluations at 0 months after treatment (T0) yielded 100% mortality rates on surfaces treated with one layer at 1 kg/6 sq m against susceptible strains of An. gambiae and Cx. quinquefasciatus. Testing for long-term efficacy in the field gave mortality rates of 96-100% after an overnight exposition at a distance of 1 m for up to 12 months in huts where a larger volume was treated (walls and ceilings) with one or two layers of insecticide paint. Conclusion A comprehensive evaluation of the full profile of insecticide products, both upon contact and spatially, may help rationalize vector control efforts more efficiently. Treating a large enough volume may extend a product’s mortality efficacy in the long-term, which contact tests would fail to assess. It is hereby proposed to explore the development of cost effective methods to assess spatial mortality and to include them as one additional measurement of insecticide efficacy against mosquitoes and other arthropod vectors in WHOPES Phase I and Phase II studies. PMID:24139513

  20. Human antibody response to Anopheles saliva for comparing the efficacy of three malaria vector control methods in Balombo, Angola.

    PubMed

    Brosseau, Laura; Drame, Papa Makhtar; Besnard, Patrick; Toto, Jean-Claude; Foumane, Vincent; Le Mire, Jacques; Mouchet, François; Remoue, Franck; Allan, Richard; Fortes, Filomeno; Carnevale, Pierre; Manguin, Sylvie

    2012-01-01

    Human antibody (Ab) response to Anopheles whole saliva, used as biomarker of Anopheles exposure, was investigated over a period of two years (2008-2009), in children between 2 to 9 years old, before and after the introduction of three different malaria vector control methods; deltamethrin treated long lasting impregnated nets (LLIN) and insecticide treated plastic sheeting (ITPS)--Zero Fly®) (ITPS-ZF), deltamethrin impregnated Durable (Wall) Lining (ITPS-DL--Zerovector®) alone, and indoor residual spraying (IRS) with lambdacyhalothrin alone. These different vector control methods resulted in considerable decreases in all three entomological (82.4%), parasitological (54.8%) and immunological criteria analyzed. The highest reductions in the number of Anopheles collected and number of positive blood smears, respectively 82.1% and 58.3%, were found in Capango and Canjala where LLIN and ITPS-ZF were implemented. The immunological data based on the level of anti-saliva IgG Ab in children of all villages dropped significantly from 2008 to 2009, except in Chissequele. These results indicated that these three vector control methods significantly reduced malaria infections amongst the children studied and IRS significantly reduced the human-Anopheles contact. The number of Anopheles, positive blood smears, and the levels of anti-saliva IgG Ab were most reduced when LLIN and ITPS-ZF were used in combination, compared to the use of one vector control method alone, either ITPS-DL or IRS. Therefore, as a combination of two vector control methods is significantly more effective than one control method only, this control strategy should be further developed at a more global scale. PMID:23028499

  1. Mammalian safety of microbial agents for vector control: a WHO memorandum.

    PubMed

    1981-01-01

    This Memorandum outlines recommended safety tests for application to biological agents under consideration for widespread use for pest control. The basic principles utilized in developing these recommendations were that: (i) the hazards presented by microbial pesticides are inherently different from those associated with chemical pesticides and the tests used to determine hazard potential to man should reflect this; (ii) a high proportion of negative results is likely; (iii) tiered testing systems should be used; negative data obtained at any level would obviate the need for further testing; (iv) the primary tier testing protocols should be designed to expose test animals to the microbial agents under conditions that provide maximum opportunity for the expression of any adverse effects.Outlines of tests proposed for use with four groups of biological agents (bacteria, fungi, protozoa, and viruses) are given. The safety tests required at each level of development of a microbial agent are described.The present status of safety testing of the agents already under development for possible use in vector control is considered. It is concluded that, for Bacillus thuringiensis H-14 and B. sphaericus, a level of safety testing has been reached that permits their use in large-scale field trials.Suggestions for applied research are made, covering safety aspects of cottage-industry production of microbial agents, studies on allergic responses, serological surveys on laboratory workers, and the investigation of environmental persistence of newly developed agents. PMID:6978192

  2. Influence of stimuli colour in SSVEP-based BCI wheelchair control using support vector machines.

    PubMed

    Singla, Rajesh; Khosla, Arun; Jha, Rameshwar

    2014-04-01

    This study aims to develop a Steady State Visual Evoked Potential (SSVEP)-based Brain Computer Interface (BCI) system to control a wheelchair, with improving accuracy as the major goal. The developed wheelchair can move in forward, backward, left, right and stop positions. Four different flickering frequencies in the low frequency region were used to elicit the SSVEPs and were displayed on a Liquid Crystal Display (LCD) monitor using LabVIEW. Four colours (green, red, blue and violet) were included in the study to investigate the colour influence in SSVEPs. The Electroencephalogram (EEG) signals recorded from the occipital region were first segmented into 1?s windows and features were extracted by using Fast Fourier Transform (FFT). Three different classifiers, two based on Artificial Neural Network (ANN) and one based on Support Vector Machine (SVM), were compared to yield better accuracy. Twenty subjects participated in the experiment and the accuracy was calculated by considering the number of correct detections produced while performing a pre-defined movement sequence. SSVEP with violet colour showed higher performance than green and red. The One-Against-All (OAA) based multi-class SVM classifier showed better accuracy than the ANN classifiers. The classification accuracy over 20 subjects varies between 75-100%, while information transfer rates (ITR) varies from 12.13-27 bpm for BCI wheelchair control with SSVEPs elicited by violet colour stimuli and classified using OAA-SVM. PMID:24533888

  3. might, however, be a cheap and effective alternative to conventional pesticides for vector control, and one that

    E-print Network

    deYoung, Brad

    . (2005) An entomopathogenic fungus for control of adult African malaria mosquitoes. Science 308, 1641 in Anopheles gambiae: tests of non-pyrethroid insecticides and a new detection method for the gene malaria transmission by genetic manipulation of anopheline mosquitoes. J. Vector Borne Dis. 40, 73­77 12

  4. Novel Technique of Contact Force Vector Determination Aimed at Control of Service Robot Arm and Estimation of Environment Stiffness

    E-print Network

    Tachi, Susumu

    of the applied force vector at any point of the robot arm and its technical realization. The experimental results. Keywords: Sensitive robot arm, robot-environment interaction, contact transition control. 1. INTRODUCTION-speed vision system attached to the robot arm allows real-time collision avoidance [2]. However, even

  5. Development and assessment of plant-based synthetic odor baits for surveillance and control of Malaria vectors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent malaria vector control measures have considerably reduced indoor biting mosquito populations. However, reducing the outdoor biting populations remains a challenge because of the unavailability of appropriate lures to achieve this. This study sought to test the efficacy of plant-based syntheti...

  6. False Positivity of Non-Targeted Infections in Malaria Rapid Diagnostic Tests: The Case of Human African Trypanosomiasis

    PubMed Central

    Gillet, Philippe; Mumba Ngoyi, Dieudonné; Lukuka, Albert; Kande, Viktor; Atua, Benjamin; van Griensven, Johan; Muyembe, Jean-Jacques; Jacobs, Jan; Lejon, Veerle

    2013-01-01

    Background In endemic settings, diagnosis of malaria increasingly relies on the use of rapid diagnostic tests (RDTs). False positivity of such RDTs is poorly documented, although it is especially relevant in those infections that resemble malaria, such as human African trypanosomiasis (HAT). We therefore examined specificity of malaria RDT products among patients infected with Trypanosoma brucei gambiense. Methodology/Principal Findings Blood samples of 117 HAT patients and 117 matched non-HAT controls were prospectively collected in the Democratic Republic of the Congo. Reference malaria diagnosis was based on real-time PCR. Ten commonly used malaria RDT products were assessed including three two-band and seven three-band products, targeting HRP-2, Pf-pLDH and/or pan-pLDH antigens. Rheumatoid factor was determined in PCR negative subjects. Specificity of the 10 malaria RDT products varied between 79.5 and 100% in HAT-negative controls and between 11.3 and 98.8% in HAT patients. For seven RDT products, specificity was significantly lower in HAT patients compared to controls. False positive reactions in HAT were mainly observed for pan-pLDH test lines (specificities between 13.8 and 97.5%), but also occurred frequently for the HRP-2 test line (specificities between 67.9 and 98.8%). The Pf-pLDH test line was not affected by false-positive lines in HAT patients (specificities between 97.5 and 100%). False positivity was not associated to rheumatoid factor, detected in 7.6% of controls and 1.2% of HAT patients. Conclusions/Significance Specificity of some malaria RDT products in HAT was surprisingly low, and constitutes a risk for misdiagnosis of a fatal but treatable infection. Our results show the importance to assess RDT specificity in non-targeted infections when evaluating diagnostic tests. PMID:23638201

  7. Linear Test Bed. Volume 2: Test Bed No. 2. [linear aerospike test bed for thrust vector control

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Test bed No. 2 consists of 10 combustors welded in banks of 5 to 2 symmetrical tubular nozzle assemblies, an upper stationary thrust frame, a lower thrust frame which can be hinged, a power package, a triaxial combustion wave ignition system, a pneumatic control system, pneumatically actuated propellant valves, a purge and drain system, and an electrical control system. The power package consists of the Mark 29-F fuel turbopump, the Mark 29-0 oxidizer turbopump, a gas generator assembly, and propellant ducting. The system, designated as a linear aerospike system, was designed to demonstrate the feasibility of the concept and to explore technology related to thrust vector control, thrust vector optimization, improved sequencing and control, and advanced ignition systems. The propellants are liquid oxygen/liquid hydrogen. The system was designed to operate at 1200-psia chamber pressure at an engine mixture ratio of 5.5. With 10 combustors, the sea level thrust is 95,000 pounds.

  8. Ecologists can enable communities to implement malaria vector control in Africa

    PubMed Central

    Mukabana, W Richard; Kannady, Khadija; Kiama, G Michael; Ijumba, Jasper N; Mathenge, Evan M; Kiche, Ibrahim; Nkwengulila, Gamba; Mboera, Leonard; Mtasiwa, Deo; Yamagata, Yoichi; van Schayk, Ingeborg; Knols, Bart GJ; Lindsay, Steven W; de Castro, Marcia Caldas; Mshinda, Hassan; Tanner, Marcel; Fillinger, Ulrike; Killeen, Gerry F

    2006-01-01

    Background Integrated vector management (IVM) for malaria control requires ecological skills that are very scarce and rarely applied in Africa today. Partnerships between communities and academic ecologists can address this capacity deficit, modernize the evidence base for such approaches and enable future scale up. Methods Community-based IVM programmes were initiated in two contrasting settings. On Rusinga Island, Western Kenya, community outreach to a marginalized rural community was achieved by University of Nairobi through a community-based organization. In Dar es Salaam, Tanzania, Ilala Municipality established an IVM programme at grassroots level, which was subsequently upgraded and expanded into a pilot scale Urban Malaria Control Programme with support from national academic institutes. Results Both programmes now access relevant expertise, funding and policy makers while the academic partners benefit from direct experience of community-based implementation and operational research opportunities. The communities now access up-to-date malaria-related knowledge and skills for translation into local action. Similarly, the academic partners have acquired better understanding of community needs and how to address them. Conclusion Until sufficient evidence is provided, community-based IVM remains an operational research activity. Researchers can never directly support every community in Africa so community-based IVM strategies and tactics will need to be incorporated into undergraduate teaching programmes to generate sufficient numbers of practitioners for national scale programmes. Academic ecologists at African institutions are uniquely positioned to enable the application of practical environmental and entomological skills for malaria control by communities at grassroots level and should be supported to fulfil this neglected role. PMID:16457724

  9. American Trypanosomiasis (Also Known as Chagas Disease) Triatomine Bug FAQs

    MedlinePLUS

    ... plastered walls and sealed entryways to prevent insect invasion, triatomine bugs rarely infest indoor areas of houses. ... Screening FAQs Triatomine Bug FAQs Epidemiology & Risk Factors Biology Disease Diagnosis Treatment Prevention & Control Resources for Health ...

  10. American Trypanosomiasis (Also Known as Chagas Disease) Blood Screening FAQs

    MedlinePLUS

    ... with a health care provider. If you have any questions about the parasites described above or think that you may have a parasitic ... Us: Centers for Disease Control and Prevention 1600 Clifton Rd Atlanta, GA 30333 ...

  11. Inductance and Active Phase Vector Based Torque Control for Switched Reluctance Motor Drives.

    NASA Astrophysics Data System (ADS)

    Kalpathi, Ramani Raman

    The Switched Reluctance Motor (SRM) drive technology has developed significantly over the last few years. The simplicity in both motor design and power converter requirement along with the availability of high frequency, high power semiconductor switches have made SRMs compete with conventional adjustable speed drive technologies. The subject of winding current control in switched reluctance machines has always been associated with the shaft position information. The use of inductance for direct commutation control is the central subject of this dissertation. In contrast to the conventional methods based on position commutation, new methods of control based on inductance commutation are presented. The object of a commutation algorithm is to switch the currents in the phase coils, in order to provide continuous energy conversion with maximum torque output for a given unit of input current. Since torque production in a SRM is based on the concept of variable reluctance, it makes more sense to observe the instantaneous phase inductance or reluctance instead of estimating the rotor position. The inductance sensors observe the machine parameters and provide sufficient information on the electrical characteristics of the coils. This control strategy avoids the inductance to position transformation blocks conventionally used in SRM control systems. In a typical SRM, the phase coils have a nonlinear behavior of inductance due to effects of current saturation. Also the parameters of one phase coil differ from those of the other due to manufacturing tolerances or due to bearing wear. In such cases, the algorithms written during the stage of manufacturing may not be valid after parameter changes. Optimizing torque production in the event of phase asymmetry and saturation is developed in this research. Indirect sensors connected to the active phase coil of the SRM are based on sensing the flux level in the active coil. New commutation algorithms based on flux sensing concepts are derived and commutation based on observable phase coil parameters are developed. The commutation methods are based on a composite vector of the observable parameters of the active phase coil. These methods work on a tabular approach which is ideal for implementation using digital computers.

  12. Application of Diagnostic Analysis Tools to the Ares I Thrust Vector Control System

    NASA Technical Reports Server (NTRS)

    Maul, William A.; Melcher, Kevin J.; Chicatelli, Amy K.; Johnson, Stephen B.

    2010-01-01

    The NASA Ares I Crew Launch Vehicle is being designed to support missions to the International Space Station (ISS), to the Moon, and beyond. The Ares I is undergoing design and development utilizing commercial-off-the-shelf tools and hardware when applicable, along with cutting edge launch technologies and state-of-the-art design and development. In support of the vehicle s design and development, the Ares Functional Fault Analysis group was tasked to develop an Ares Vehicle Diagnostic Model (AVDM) and to demonstrate the capability of that model to support failure-related analyses and design integration. One important component of the AVDM is the Upper Stage (US) Thrust Vector Control (TVC) diagnostic model-a representation of the failure space of the US TVC subsystem. This paper first presents an overview of the AVDM, its development approach, and the software used to implement the model and conduct diagnostic analysis. It then uses the US TVC diagnostic model to illustrate details of the development, implementation, analysis, and verification processes. Finally, the paper describes how the AVDM model can impact both design and ground operations, and how some of these impacts are being realized during discussions of US TVC diagnostic analyses with US TVC designers.

  13. [History of human African trypanosomiasis in Moyen-Chari (Chad)].

    PubMed

    Milleliri, J M; Tirandibaye, H N

    1989-01-01

    The authors give on historical record of the focus of the sleeping disease in Moyen-Chari (South of Chad) from 1914 to 1989. Over such a period, they describe the fighting means used to control this endemic disease. PMID:2695735

  14. Specific Cell Targeting Therapy Bypasses Drug Resistance Mechanisms in African Trypanosomiasis

    PubMed Central

    Unciti-Broceta, Juan D.; Arias, José L.; Maceira, José; Soriano, Miguel; Ortiz-González, Matilde; Hernández-Quero, José; Muñóz-Torres, Manuel; de Koning, Harry P.; Magez, Stefan; Garcia-Salcedo, José A.

    2015-01-01

    African trypanosomiasis is a deadly neglected disease caused by the extracellular parasite Trypanosoma brucei. Current therapies are characterized by high drug toxicity and increasing drug resistance mainly associated with loss-of-function mutations in the transporters involved in drug import. The introduction of new antiparasitic drugs into therapeutic use is a slow and expensive process. In contrast, specific targeting of existing drugs could represent a more rapid and cost-effective approach for neglected disease treatment, impacting through reduced systemic toxicity and circumventing resistance acquired through impaired compound uptake. We have generated nanoparticles of chitosan loaded with the trypanocidal drug pentamidine and coated by a single domain nanobody that specifically targets the surface of African trypanosomes. Once loaded into this nanocarrier, pentamidine enters trypanosomes through endocytosis instead of via classical cell surface transporters. The curative dose of pentamidine-loaded nanobody-chitosan nanoparticles was 100-fold lower than pentamidine alone in a murine model of acute African trypanosomiasis. Crucially, this new formulation displayed undiminished in vitro and in vivo activity against a trypanosome cell line resistant to pentamidine as a result of mutations in the surface transporter aquaglyceroporin 2. We conclude that this new drug delivery system increases drug efficacy and has the ability to overcome resistance to some anti-protozoal drugs. PMID:26110623

  15. Magnetic Resonance Imaging to Assess Blood–Brain Barrier Damage in Murine Trypanosomiasis

    PubMed Central

    Rodgers, Jean; McCabe, Christopher; Gettinby, George; Bradley, Barbara; Condon, Barrie; Kennedy, Peter G. E.

    2011-01-01

    The ability of trypanosomes to invade the brain and induce an inflammatory reaction is well-recognized. This study uses magnetic resonance imaging (MRI) in conjunction with a murine model of central nervous system (CNS) stage trypanosomiasis to investigate this phenomenon at the level of the blood–brain barrier (BBB). Mice were scanned before and after administration of the contrast agent. Signal enhancement maps were generated, and the percentage signal change was calculated. The severity of the neuroinflammation was also assessed. Statistical analysis of the signal change data revealed a significantly (P = 0.028) higher signal enhancement in mice at 28 days post-infection (least squares mean = 26.709) compared with uninfected animals (6.298), indicating the presence of BBB impairment. Leukocytes were found in the meninges and perivascular space of some blood vessels in the infected mice. This study shows that the integrity of the BBB is compromised during CNS stage trypanosomiasis and that the impairment does not correlate with inflammatory cell infiltration. PMID:21292912

  16. Trypanosoma brucei gambiense Spliced Leader RNA Is a More Specific Marker for Cure of Human African Trypanosomiasis Than T. b. gambiense DNA.

    PubMed

    Ilboudo, Hamidou; Camara, Oumou; Ravel, Sophie; Bucheton, Bruno; Lejon, Veerle; Camara, Mamadou; Kaboré, Jacques; Jamonneau, Vincent; Deborggraeve, Stijn

    2015-12-15

    To assess the efficacy of treatment for human African trypanosomiasis, accurate tests that can discriminate relapse from cure are needed. We report the first data that the spliced leader (SL) RNA is a more specific marker for cure of human African trypanosomiasis than parasite DNA. In blood samples obtained from 61 patients in whom human African trypanosomiasis was cured, SL RNA detection had specificities of 98.4%-100%, while DNA detection had a specificity of only 77%. Data from our proof-of-concept study show that SL RNA detection has high potential as a test of cure. PMID:26080371

  17. A new space vector PWM control strategy for high performance converters 

    E-print Network

    Xie, Bin

    1993-01-01

    A new space vector PWM technique is presented in this thesis. Application of the proposed modulator in a) Alternating Current (AC) to Direct Current (DC) rectifier b) DC to AC inverter system is investigated. The new space ...

  18. Hydrologic modeling to screen potential environmental management methods for malaria vector control in Niger

    E-print Network

    Gianotti, Rebecca Louise

    This paper describes the first use of Hydrology-Entomology and Malaria Transmission Simulator (HYDREMATS), a physically based distributed hydrology model, to investigate environmental management methods for malaria vector ...

  19. Development and Assessment of Plant-Based Synthetic Odor Baits for Surveillance and Control of Malaria Vectors

    PubMed Central

    Nyasembe, Vincent O.; Tchouassi, David P.; Kirwa, Hillary K.; Foster, Woodbridge A.; Teal, Peter E. A.; Borgemeister, Christian; Torto, Baldwyn

    2014-01-01

    Background Recent malaria vector control measures have considerably reduced indoor biting mosquito populations. However, reducing the outdoor biting populations remains a challenge because of the unavailability of appropriate lures to achieve this. This study sought to test the efficacy of plant-based synthetic odor baits in trapping outdoor populations of malaria vectors. Methodology and Principal Finding Three plant-based lures ((E)-linalool oxide [LO], (E)-linalool oxide and (E)-?-ocimene [LO + OC], and a six-component blend comprising (E)-linalool oxide, (E)-?-ocimene, hexanal, ?-pinene, limonene, and (E)-?-farnesene [Blend C]), were tested alongside an animal/human-based synthetic lure (comprising heptanal, octanal, nonanal, and decanal [Blend F]) and worn socks in a malaria endemic zone in the western part of Kenya. Mosquito Magnet-X (MM-X) and lightless Centre for Disease Control (CDC) light traps were used. Odor-baited traps were compared with traps baited with either solvent alone or solvent + carbon dioxide (controls) for 18 days in a series of randomized incomplete-block designs of days × sites × treatments. The interactive effect of plant and animal/human odor was also tested by combining LO with either Blend F or worn socks. Our results show that irrespective of trap type, traps baited with synthetic plant odors compared favorably to the same traps baited with synthetic animal odors and worn socks in trapping malaria vectors, relative to the controls. Combining LO and worn socks enhanced trap captures of Anopheles species while LO + Blend F recorded reduced trap capture. Carbon dioxide enhanced total trap capture of both plant- and animal/human-derived odors. However, significantly higher proportions of male and engorged female Anopheles gambiae s.l. were caught when the odor treatments did not include carbon dioxide. Conclusion and Significance The results highlight the potential of plant-based odors and specifically linalool oxide, with or without carbon dioxide, for surveillance and mass trapping of malaria vectors. PMID:24587059

  20. Preliminary Investigation on Battery Sizing Investigation for Thrust Vector Control on Ares I and Ares V Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Miller, Thomas B.

    2011-01-01

    An investigation into the merits of battery powered Electro Hydrostatic Actuation (EHA) for Thrust Vector Control (TVC) of the Ares I and Ares V launch vehicles is described. A top level trade study was conducted to ascertain the technical merits of lithium-ion (Li-ion) and thermal battery performance to determine the preferred choice of an energy storage system chemistry that provides high power discharge capability for a relatively short duration.

  1. Heterophile antibodies, M-antiglobulins and immunoglobulins in experimental trypanosomiasis

    PubMed Central

    Houba, V.; Brown, K. N.; Allison, A. C.

    1969-01-01

    Monkeys (Macaca mulatto) were infected with different strains of Trypanosoma rhodesiense, T. gambiense and T. brucei. The titres of non-sensitized sheep cell agglutinins (NSCAT), M-antiglobulins (rheumatoid factor-like globulins) and the levels of immunoglobulins (IgG, IgA and IgM) were determined in sera before and during the course of infections controlled by treatment with Suramin. Persistently high titres of NSCAT-agglutinins developed in monkeys infected with all three organisms. IgM levels increased in all animals reaching levels more than ten times the original values. The levels of IgA remained unchanged and of IgG slightly increased in some animals. Slightly elevated M-antiglobulin titres were occasionally found without any relation to the progress of infection. NSCAT-agglutinins were found to be macroglobulins (Sephadex G-200 immunoelectrophoresis, S20 = 18·5) sensitive to ?-mercaptoethanol treatment. Their activity was absorbed by sheep red blood cells, guinea-pig kidney cells and T. rhodesiense antigen. ImagesFIG. 4 PMID:4182355

  2. Loss of genetic diversity in Culex quinquefasciatus targeted by a lymphatic filariasis vector control program in Recife, Brazil.

    PubMed

    Cartaxo, Marina F S; Ayres, Constância F J; Weetman, David

    2011-09-01

    Recife is one of the largest cities in north-eastern Brazil and is endemic for lymphatic filariasis transmitted by Culex quinquefasciatus. Since 2003 a control program has targeted mosquito larvae by elimination of breeding sites and bimonthly application of Bacillus sphaericus. To assess the impact of this program on the local vector population we monitored the genetic diversity and differentiation of Cx. quinquefasciatus using microsatellites and a B. sphaericus-resistance associated mutation (cqm1(REC)) over a 3-year period. We detected a significant but gradual decline in allelic diversity, which, coupled with subtle temporal genetic structure, suggests a major impact of the control program on the vector population. Selection on cqm1(REC) does not appear to be involved with loss of neutral diversity from the population, with no temporal trend in resistant allele frequency and no correlation with microsatellite differentiation. The evidence for short-term genetic drift we detected suggests a low ratio of effective population size: census population size for Cx. quinquefasciatus, perhaps coupled with strong geographically-restricted population structure. Spatial definition of populations will be an important step for success of an expanded vector control program. PMID:21737112

  3. Cultivation-Independent Methods Reveal Differences among Bacterial Gut Microbiota in Triatomine Vectors of Chagas Disease

    PubMed Central

    da Mota, Fabio Faria; Marinho, Lourena Pinheiro; Moreira, Carlos José de Carvalho; Lima, Marli Maria; Mello, Cícero Brasileiro; Garcia, Eloi Souza; Carels, Nicolas; Azambuja, Patricia

    2012-01-01

    Background Chagas disease is a trypanosomiasis whose agent is the protozoan parasite Trypanosoma cruzi, which is transmitted to humans by hematophagous bugs known as triatomines. Even though insecticide treatments allow effective control of these bugs in most Latin American countries where Chagas disease is endemic, the disease still affects a large proportion of the population of South America. The features of the disease in humans have been extensively studied, and the genome of the parasite has been sequenced, but no effective drug is yet available to treat Chagas disease. The digestive tract of the insect vectors in which T. cruzi develops has been much less well investigated than blood from its human hosts and constitutes a dynamic environment with very different conditions. Thus, we investigated the composition of the predominant bacterial species of the microbiota in insect vectors from Rhodnius, Triatoma, Panstrongylus and Dipetalogaster genera. Methodology/Principal Findings Microbiota of triatomine guts were investigated using cultivation-independent methods, i.e., phylogenetic analysis of 16s rDNA using denaturing gradient gel electrophoresis (DGGE) and cloned-based sequencing. The Chao index showed that the diversity of bacterial species in triatomine guts is low, comprising fewer than 20 predominant species, and that these species vary between insect species. The analyses showed that Serratia predominates in Rhodnius, Arsenophonus predominates in Triatoma and Panstrongylus, while Candidatus Rohrkolberia predominates in Dipetalogaster. Conclusions/Significance The microbiota of triatomine guts represents one of the factors that may interfere with T. cruzi transmission and virulence in humans. The knowledge of its composition according to insect species is important for designing measures of biological control for T. cruzi. We found that the predominant species of the bacterial microbiota in triatomines form a group of low complexity whose structure differs according to the vector genus. PMID:22563511

  4. Biological implications of selenium and its role in trypanosomiasis treatment.

    PubMed

    da Silva, M T A; Silva-Jardim, I; Thiemann, O H

    2014-01-01

    Selenium (Se) is an essential trace element for several organisms and is present in proteins as selenocysteine (Sec or U), an amino acid that is chemically distinct from serine and cysteine by a single atom (Se instead of O or S, respectively). Sec is incorporated into selenoproteins at an in-frame UGA codon specified by an mRNA stem-loop structure called the selenocysteine incorporating sequence (SECIS) presented in selenoprotein mRNA and specific selenocysteine synthesis and incorporation machinery. Selenoproteins are presented in all domains but are not found in all organisms. Although several functions have been attributed to this class, the majority of the proteins are involved in oxidative stress defense. Here, we discuss the kinetoplastid selenocysteine pathway and how selenium supplementation is able to alter the infection course of trypanosomatids in detail. These organisms possess the canonical elements required for selenoprotein production such as phosphoseryl tRNA kinase (PSTK), selenocysteine synthase (SepSecS), selenophosphase synthase (SelD or SPS), and elongation factor EFSec (SelB), whereas other important factors presented in mammal cells, such as SECIS binding protein 2 (SBP) and SecP 43, are absent. The selenoproteome of trypanosomatids is small, as is the selenoproteome of others parasites, which is in contrast to the large number of selenoproteins found in bacteria, aquatic organisms and higher eukaryotes. Trypanosoma and Leishmania are sensitive to auranofin, a potent selenoprotein inhibitor; however, the probable drug mechanism is not related to selenoproteins in kinetoplastids. Selenium supplementation decreases the parasitemia of various Trypanosome infections and reduces important parameters associated with diseases such as anemia and parasite-induced organ damage. New experiments are necessary to determine how selenium acts, but evidence suggests that immune response modulation and increased host defense against oxidative stress contribute to control of the parasite infection. PMID:24251578

  5. A review of the vector management methods to prevent and control outbreaks of West Nile virus infection and the challenge for Europe

    PubMed Central

    2014-01-01

    West Nile virus infection is a growing concern in Europe. Vector management is often the primary option to prevent and control outbreaks of the disease. Its implementation is, however, complex and needs to be supported by integrated multidisciplinary surveillance systems and to be organized within the framework of predefined response plans. The impact of the vector control measures depends on multiple factors and the identification of the best combination of vector control methods is therefore not always straightforward. Therefore, this contribution aims at critically reviewing the existing vector control methods to prevent and control outbreaks of West Nile virus infection and to present the challenges for Europe. Most West Nile virus vector control experiences have been recently developed in the US, where ecological conditions are different from the EU and vector control is organized under a different regulatory frame. The extrapolation of information produced in North America to Europe might be limited because of the seemingly different epidemiology in the European region. Therefore, there is an urgent need to analyse the European experiences of the prevention and control of outbreaks of West Nile virus infection and to perform robust cost-benefit analysis that can guide the implementation of the appropriate control measures. Furthermore, to be effective, vector control programs require a strong organisational backbone relying on a previously defined plan, skilled technicians and operators, appropriate equipment, and sufficient financial resources. A decision making guide scheme is proposed which may assist in the process of implementation of vector control measures tailored on specific areas and considering the available information and possible scenarios. PMID:25015004

  6. People's knowledge and practice about dengue, its vectors, and control means in Brasilia (DF), Brazil: its relevance with entomological factors.

    PubMed

    Dégallier, N; Vilarinhos, P T; de Carvalho, M S; Knox, M B; Caetano, J

    2000-06-01

    In South America, the epidemiology and ecology of dengue fever are strongly associated with human habits because the vector Aedes aegypti is strictly urban. Thus, the evaluation of people's knowledge and practice (PKP) is of great importance to improve integrated control measures. A PKP evaluation has been done in a suburb of Brasilia. Thirty questions were submitted to 130 habitants about income level, education, sources of information, specific knowledge about dengue, vector biology, and control measures applied. Other questions were about the responsibility of dengue control and the opportunity of applying a fine to people who would not cooperate with the control measures. Level of PKP was fairly high, either for housekeepers, workers, or students. The mosquito bite was cited as source of infection by 60.8% of interviewed people but 22.3% had no knowledge about this topic. The most cited symptoms in association with dengue were fever (73.1%), headache (66.2%), and rash (35.4%). Knowledge about mosquito biology and control was also fairly accurate, as demonstrated by 96.9% of answers. Elimination of water containers was the most efficient means according to 73% of people. Such action should be done mainly by the citizen (75.3% of answers). Despite the good PKP, correlations existed only between the PKP about vector biology and presence of potential breeding containers in March, and between the PKP about the disease and potential breeding containers in April. In conclusion, global educational campaigns may have a real impact on the PKP but this did not result in effective control of the mosquito breeding containers by the people. PMID:10901634

  7. Screening Mosquito House Entry Points as a Potential Method for Integrated Control of Endophagic Filariasis, Arbovirus and Malaria Vectors

    PubMed Central

    Ogoma, Sheila B.; Lweitoijera, Dickson W.; Ngonyani, Hassan; Furer, Benjamin; Russell, Tanya L.; Mukabana, Wolfgang R.; Killeen, Gerry F.; Moore, Sarah J.

    2010-01-01

    Background Partial mosquito-proofing of houses with screens and ceilings has the potential to reduce indoor densities of malaria mosquitoes. We wish to measure whether it will also reduce indoor densities of vectors of neglected tropical diseases. Methodology The main house entry points preferred by anopheline and culicine vectors were determined through controlled experiments using specially designed experimental huts and village houses in Lupiro village, southern Tanzania. The benefit of screening different entry points (eaves, windows and doors) using PVC-coated fibre glass netting material in terms of reduced indoor densities of mosquitoes was evaluated compared to the control. Findings 23,027 mosquitoes were caught with CDC light traps; 77.9% (17,929) were Anopheles gambiae sensu lato, of which 66.2% were An. arabiensis and 33.8% An. gambiae sensu stricto. The remainder comprised 0.2% (50) An. funestus, 10.2% (2359) Culex spp. and 11.6% (2664) Mansonia spp. Screening eaves reduced densities of Anopheles gambiae s. l. (Relative ratio (RR) ?=?0.91; 95% CI?=?0.84, 0.98; P?=?0.01); Mansonia africana (RR?=?0.43; 95% CI?=?0.26, 0.76; P<0.001) and Mansonia uniformis (RR?=?0.37; 95% CI?=?0.25, 0.56; P<0.001) but not Culex quinquefasciatus, Cx. univittatus or Cx. theileri. Numbers of these species were reduced by screening windows and doors but this was not significant. Significance This study confirms that across Africa, screening eaves protects households against important mosquito vectors of filariasis, Rift Valley Fever and O'Nyong nyong as well as malaria. While full house screening is required to exclude Culex species mosquitoes, screening of eaves alone or fitting ceilings has considerable potential for integrated control of other vectors of filariasis, arbovirus and malaria. PMID:20689815

  8. Pharmacokinetic Comparison To Determine the Mechanisms Underlying the Differential Efficacies of Cationic Diamidines against First- and Second-Stage Human African Trypanosomiasis

    E-print Network

    Yang, Sihyung; Wenzler, Tanja; Miller, Patrik N.; Wu, Huali; Boykin, David W.; Brun, Reto; Wang, Zhuo

    2014-05-05

    Human African trypanosomiasis (HAT), a neglected tropical disease, is fatal without treatment. Pentamidine, a cationic diamidine, has been used to treat first-stage (hemolymphatic) HAT since the 1940s, but it is ineffective against second...

  9. Modeling Transmission Dynamics and Control of Vector-Borne Neglected Tropical Diseases

    PubMed Central

    Luz, Paula M.; Struchiner, Claudio J.; Galvani, Alison P.

    2010-01-01

    Neglected tropical diseases affect more than one billion people worldwide. The populations most impacted by such diseases are typically the most resource-limited. Mathematical modeling of disease transmission and cost-effectiveness analyses can play a central role in maximizing the utility of limited resources for neglected tropical diseases. We review the contributions that mathematical modeling has made to optimizing intervention strategies of vector-borne neglected diseases. We propose directions forward in the modeling of these diseases, including integrating new knowledge of vector and pathogen ecology, incorporating evolutionary responses to interventions, and expanding the scope of sensitivity analysis in order to achieve robust results. PMID:21049062

  10. Simulation comparison of a decoupled longitudinal control system and a velocity vector control wheel steering system during landings in wind shear

    NASA Technical Reports Server (NTRS)

    Kimball, G., Jr.

    1980-01-01

    A simulator comparison of the velocity vector control wheel steering (VCWS) system and a decoupled longitudinal control system is presented. The piloting task was to use the electronic attitude direction indicator (EADI) to capture and maintain a 3 degree glide slope in the presence of wind shear and to complete the landing using the perspective runway included on the EADI. The decoupled control system used constant prefilter and feedback gains to provide steady state decoupling of flight path angle, pitch angle, and forward velocity. The decoupled control system improved the pilots' ability to control airspeed and flight path angle during the final stages of an approach made in severe wind shear. The system also improved their ability to complete safe landings. The pilots preferred the decoupled control system in severe winds and, on a pilot rating scale, rated the approach and landing task with the decoupled control system as much as 3 to 4 increments better than use of the VCWS system.

  11. Efficacy of extracts of Bacillus thuringiensis israelensis for the control of mosquito vectors.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than 1 million human cases of Chikungunya were recently reported in India. Aedes aegypti (the yellow fever mosquito) is an important disease vector in India where it transmits Chikungunya, dengue, and yellow fever viruses to humans. In this study, scientists from Bharathiar University in Coim...

  12. Versatile Viral Vector Strategies for Postscreening Target Validation and RNAi ON-Target Control.

    PubMed

    Christel, Carl J; Schmied, Patricia; Jagusch, Verena; Schrödel, Silke; Thirion, Christian; Schmitt, Kathrin; Salomon, Michael

    2015-09-01

    Our approach aims to optimize postscreening target validation strategies using viral vector-driven RNA interference (RNAi) cell models. The RNAiONE validation platform is an array of plasmid-based expression vectors that each drives tandem expression of the gene of interest (GOI) with one small hairpin RNA (shRNA) from a set of computed candidate sequences. The best-performing shRNA (>85% silencing efficiency) is then integrated in an inducible, all-in-one lentiviral vector to transduce pharmacologically relevant cell types that endogenously express the GOI. VariCHECK is used subsequently to combine the inducible knockdown with an equally inducible rescue of the GOI for ON-target phenotype verification. The complete RNAiONE-VariCHECK system relies on three key elements to ensure high predictability: (1) maximized silencing efficiencies by a focused shRNA validation process, (2) homogeneity of the RNAi cell pools by application of sophisticated viral vector technologies, and (3) exploiting the advantages of inducible expression systems. By using a reversible expression system, our strategy adds critical information to hot candidates from RNAi screens and avoids potential side effects that may be caused by other, irreversible genomic manipulation methods such as transcription activator-like effector nucleases (TALEN) or clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas). This approach will add credibility to top-hit screening candidates and protect researchers from costly misinterpretations early in the preclinical drug development process. PMID:25873558

  13. Expressed sequence tags from the black-winged sharpshooter: Application to biology and vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We identified 14 putative full-length transcripts of proteins important for the survival of the black-winged sharpshooter, BWSS, Oncometopia nigricans. The BWSS is considered a highly competent vector of several strains of the xylem-inhabiting bacterium Xylella fastidiosa, the causal agent of a numb...

  14. Recombinant viral vectored vaccines for the control of avian influenza: a review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The poultry industry has been at the forefront of developing recombinant viral vectored vaccines in an attempt to improve the immune response to vaccination. With AIV, the hemagglutinin surface glycoprotein is the key antigen for protection against infection. This allows a single gene to be transf...

  15. Using global information technology to detect, monitor, and control mosquito pest and disease vector populations.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Geographic Information Systems (GIS), image analysis, and remote sensing comprise global information technologies that are used to characterize pest and vector populations of mosquitoes. At this national meeting, scientists from ARS and McNeese State University organized and convened a half-day sym...

  16. Etiology, background, worldwide situation and control of Citrus Tristeza virus and its vectors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is readily graft-transmissible and, in nature, is spread by aphid vectors in a semi-persistent manner. CTV-decline has killed >85 million citrus trees grown on sour orange rootstock worldwide. Citrus in these areas must be grown on CTV-tolerant or resistant rootstocks. ...

  17. Gene expression in midgut tissues of Diaphorina citri: Application to biology and vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We produced a gene expression dataset from the midgut tissues of the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae). The AsCP is the primary vector associated with the spread of a devastating citrus trees disease, huanglongbing (HLB). The occurrence and spread of the AsCP and H...

  18. IMPROVEMENT OF SMVGEAR II ON VECTOR AND SCALAR MACHINES THROUGH ABSOLUTE ERROR TOLERANCE CONTROL (R823186)

    EPA Science Inventory

    The computer speed of SMVGEAR II was improved markedly on scalar and vector machines with relatively little loss in accuracy. The improvement was due to a method of frequently recalculating the absolute error tolerance instead of keeping it constant for a given set of chemistry. ...

  19. Introducing Vectors.

    ERIC Educational Resources Information Center

    Roche, John

    1997-01-01

    Suggests an approach to teaching vectors that promotes active learning through challenging questions addressed to the class, as opposed to subtle explanations. Promotes introducing vector graphics with concrete examples, beginning with an explanation of the displacement vector. Also discusses artificial vectors, vector algebra, and unit vectors.…

  20. Identification of sVSG117 as an Immunodiagnostic Antigen and Evaluation of a Dual-Antigen Lateral Flow Test for the Diagnosis of Human African Trypanosomiasis

    PubMed Central

    Sullivan, Lauren; Fleming, Jennifer; Sastry, Lalitha; Mehlert, Angela; Wall, Steven J.; Ferguson, Michael A. J.

    2014-01-01

    Background The diagnosis of human African trypanosomiasis (HAT) caused by Trypanosoma brucei gambiense relies mainly on the Card Agglutination Test for Trypanosomiasis (CATT). There is no immunodiagnostic for HAT caused by T. b. rhodesiense. Our principle aim was to develop a prototype lateral flow test that might be an improvement on CATT. Methodology/Principle Findings Pools of infection and control sera were screened against four different soluble form variant surface glycoproteins (sVSGs) by ELISA and one, sVSG117, showed particularly strong immunoreactivity to pooled infection sera. Using individual sera, sVSG117 was shown to be able to discriminate between T. b. gambiense infection and control sera by both ELISA and lateral flow test. The sVSG117 antigen was subsequently used with a previously described recombinant diagnostic antigen, rISG65, to create a dual-antigen lateral flow test prototype. The latter was used blind in a virtual field trial of 431 randomized infection and control sera from the WHO HAT Specimen Biobank. Conclusion/Significance In the virtual field trial, using two positive antigen bands as the criterion for infection, the sVSG117 and rISG65 dual-antigen lateral flow test prototype showed a sensitivity of 97.3% (95% CI: 93.3 to 99.2) and a specificity of 83.3% (95% CI: 76.4 to 88.9) for the detection of T. b. gambiense infections. The device was not as good for detecting T. b. rhodesiense infections using two positive antigen bands as the criterion for infection, with a sensitivity of 58.9% (95% CI: 44.9 to 71.9) and specificity of 97.3% (95% CI: 90.7 to 99.7). However, using one or both positive antigen band(s) as the criterion for T. b. rhodesiense infection improved the sensitivity to 83.9% (95% CI: 71.7 to 92.4) with a specificity of 85.3% (95% CI: 75.3 to 92.4). These results encourage further development of the dual-antigen device for clinical use. PMID:25033401

  1. A Method for Integrating Thrust-Vectoring and Actuated Forebody Strakes with Conventional Aerodynamic Controls on a High-Performance Fighter Airplane

    NASA Technical Reports Server (NTRS)

    Lallman, Frederick J.; Davidson, John B.; Murphy, Patrick C.

    1998-01-01

    A method, called pseudo controls, of integrating several airplane controls to achieve cooperative operation is presented. The method eliminates conflicting control motions, minimizes the number of feedback control gains, and reduces the complication of feedback gain schedules. The method is applied to the lateral/directional controls of a modified high-performance airplane. The airplane has a conventional set of aerodynamic controls, an experimental set of thrust-vectoring controls, and an experimental set of actuated forebody strakes. The experimental controls give the airplane additional control power for enhanced stability and maneuvering capabilities while flying over an expanded envelope, especially at high angles of attack. The flight controls are scheduled to generate independent body-axis control moments. These control moments are coordinated to produce stability-axis angular accelerations. Inertial coupling moments are compensated. Thrust-vectoring controls are engaged according to their effectiveness relative to that of the aerodynamic controls. Vane-relief logic removes steady and slowly varying commands from the thrust-vectoring controls to alleviate heating of the thrust turning devices. The actuated forebody strakes are engaged at high angles of attack. This report presents the forward-loop elements of a flight control system that positions the flight controls according to the desired stability-axis accelerations. This report does not include the generation of the required angular acceleration commands by means of pilot controls or the feedback of sensed airplane motions.

  2. The US Air Force Aerial Spray Unit: a history of large area disease vector control operations, WWII through Katrina.

    PubMed

    Breidenbaugh, Mark; Haagsma, Karl

    2008-01-01

    The US Air Force has had a long history of aerial applications of pesticides to fulfill a variety of missions, the most important being the protection of troops through the minimization of arthropod vectors capable of disease transmission. Beginning in World War II, aerial application of pesticides by the military has effectively controlled vector and nuisance pest populations in a variety of environments. Currently, the military aerial spray capability resides in the US Air Force Reserve (USAFR), which operates and maintains C-130 airplanes capable of a variety of missions, including ultra low volume applications for vector and nuisance pests, as well as higher volume aerial applications of herbicides and oil-spill dispersants. The USAFR aerial spray assets are the only such fixed-wing aerial spray assets within the Department of Defense. In addition to troop protection, the USAFR Aerial Spray Unit has participated in a number of humanitarian/relief missions, most recently in the response to the 2005 Hurricanes Katrina and Rita, which heavily damaged the Gulf Coasts of Louisiana, Mississippi, and Texas. This article provides historical background on the Air Force Aerial Spray Unit and describes the operations in Louisiana in the aftermath of Hurricane Katrina. PMID:20088030

  3. Spatial orientation and balance control changes induced by altered gravitoinertial force vectors.

    PubMed

    Kaufman, G D; Wood, S J; Gianna, C C; Black, F O; Paloski, W H

    2001-04-01

    To better understand the mechanisms of human adaptation to rotating environments, we exposed 19 healthy subjects and 8 vestibular-deficient subjects ("abnormal"; four bilateral and four unilateral lesions) to an interaural centripetal acceleration of 1 g (resultant 45 degrees roll-tilt of 1.4 g) on a 0.8-m-radius centrifuge for periods of 90 min. The subjects sat upright (body z-axis parallel to centrifuge rotation axis) in the dark with head stationary, except during 4 min of every 10 min, when they performed head saccades toward visual targets switched on at 3- to 5-s intervals at random locations (within +/- 30 degrees) in the earth-horizontal plane. Eight of the normal subjects also performed the head saccade protocol in a stationary chair adjusted to a static roll-tilt angle of 45 degrees for 90 min (reproducing the change in orientation but not the magnitude of the gravitoinertial force on the centrifuge). Eye movements, including voluntary saccades directed along perceived earth- and head-referenced planes, were recorded before, during, and immediately after centrifugation. Postural center of pressure (COP) and multisegment body kinematics were also gathered before and within 10 min after centrifugation. Normal subjects overestimated roll-tilt during centrifugation and revealed errors in perception of head-vertical provided by directed saccades. Errors in this perceptual response tended to increase with time and became significant after approximately 30 min. Motion-sickness symptoms caused approximately 25% of normal subjects to limit their head movements during centrifugation and led three normal subjects to stop the test early. Immediately after centrifugation, subjects reported feeling tilted 10 degrees in the opposite direction, which was in agreement with the direction of their earth-referenced directed saccades. Postural COP, segmental body motion amplitude, and hip-sway frequency increased significantly after centrifugation. These postural effects were short-lived, however, with a recovery time of several postural test trials (minutes). There were also asymmetries in the direction of postcentrifugation COP and head tilt which depended on the subject's orientation during the centrifugation adaptation period (left ear or right ear out). The amount of total head movements during centrifugation correlated poorly or inversely with postcentrifugation postural stability, and the most unstable subject made no head movements. There was no decrease in postural stability after static tilt, although these subjects also reported a perceived tilt briefly after return to upright, and they also had COP asymmetries. Abnormal subjects underestimated roll-tilt during centrifugation, and their directed saccades revealed permanent spatial distortions. Bilateral abnormal subjects started out with poor postural control, but showed no postural decrements after centrifugation, while unilateral abnormal subjects had varying degrees of postural decrement, both in their everyday function and as a result of experiencing the centrifugation. In addition, three unilateral, abnormal subjects, who rode twice in opposite orientations, revealed a consistent orthogonal pattern of COP offsets after centrifugation. These results suggest that both orientation and magnitude of the gravitoinertial vector are used by the central nervous system for calibration of multiple orientation systems. A change in the background gravitoinertial force (otolith input) can rapidly initiate postural and perceptual adaptation in several sensorimotor systems, independent of a structured visual surround. PMID:11355385

  4. Spatial orientation and balance control changes induced by altered gravitoinertial force vectors

    NASA Technical Reports Server (NTRS)

    Kaufman, G. D.; Wood, S. J.; Gianna, C. C.; Black, F. O.; Paloski, W. H.

    2001-01-01

    To better understand the mechanisms of human adaptation to rotating environments, we exposed 19 healthy subjects and 8 vestibular-deficient subjects ("abnormal"; four bilateral and four unilateral lesions) to an interaural centripetal acceleration of 1 g (resultant 45 degrees roll-tilt of 1.4 g) on a 0.8-m-radius centrifuge for periods of 90 min. The subjects sat upright (body z-axis parallel to centrifuge rotation axis) in the dark with head stationary, except during 4 min of every 10 min, when they performed head saccades toward visual targets switched on at 3- to 5-s intervals at random locations (within +/- 30 degrees) in the earth-horizontal plane. Eight of the normal subjects also performed the head saccade protocol in a stationary chair adjusted to a static roll-tilt angle of 45 degrees for 90 min (reproducing the change in orientation but not the magnitude of the gravitoinertial force on the centrifuge). Eye movements, including voluntary saccades directed along perceived earth- and head-referenced planes, were recorded before, during, and immediately after centrifugation. Postural center of pressure (COP) and multisegment body kinematics were also gathered before and within 10 min after centrifugation. Normal subjects overestimated roll-tilt during centrifugation and revealed errors in perception of head-vertical provided by directed saccades. Errors in this perceptual response tended to increase with time and became significant after approximately 30 min. Motion-sickness symptoms caused approximately 25% of normal subjects to limit their head movements during centrifugation and led three normal subjects to stop the test early. Immediately after centrifugation, subjects reported feeling tilted 10 degrees in the opposite direction, which was in agreement with the direction of their earth-referenced directed saccades. Postural COP, segmental body motion amplitude, and hip-sway frequency increased significantly after centrifugation. These postural effects were short-lived, however, with a recovery time of several postural test trials (minutes). There were also asymmetries in the direction of postcentrifugation COP and head tilt which depended on the subject's orientation during the centrifugation adaptation period (left ear or right ear out). The amount of total head movements during centrifugation correlated poorly or inversely with postcentrifugation postural stability, and the most unstable subject made no head movements. There was no decrease in postural stability after static tilt, although these subjects also reported a perceived tilt briefly after return to upright, and they also had COP asymmetries. Abnormal subjects underestimated roll-tilt during centrifugation, and their directed saccades revealed permanent spatial distortions. Bilateral abnormal subjects started out with poor postural control, but showed no postural decrements after centrifugation, while unilateral abnormal subjects had varying degrees of postural decrement, both in their everyday function and as a result of experiencing the centrifugation. In addition, three unilateral, abnormal subjects, who rode twice in opposite orientations, revealed a consistent orthogonal pattern of COP offsets after centrifugation. These results suggest that both orientation and magnitude of the gravitoinertial vector are used by the central nervous system for calibration of multiple orientation systems. A change in the background gravitoinertial force (otolith input) can rapidly initiate postural and perceptual adaptation in several sensorimotor systems, independent of a structured visual surround.

  5. Progress in directed energy control of vectors for microbes and other cells

    NASA Astrophysics Data System (ADS)

    Kiel, Johnathan L.; Parker, Jill E.; Holwitt, Eric A.; Vivekananda, Jeeva; Sloan, Mark A.; Stribling, Lucille J. V.

    2004-07-01

    Biosynthetic semiconductor, diazoluminomelanin (DALM), is a polymer of tyrosine, luminol, and nitrite. DALM has a very large cross section of absorption for light from ultraviolet to radio frequencies. This polymer can be made efficiently in a genetically engineered E.coli, JM109/pIC2ORNR1.1 (ATCC# 69905). We have been pursuing ways to couple electromagnetic radiation to vectors using this polymer. DNA capture elements (DCEs; formerly aptamers) have made this possible. We incorporated DCEs into the plasmid of this E. coli to direct binding to whatever microbe or cell desired and to produce DALM attached to the plasmid DNA. Using two other vectors pSV2neoNR101 or pSV2neoNR8005 (ATCC # 69617 and 69618, respectively), both propagated in the E. coli host HB101, we have also inserted genes necessary for DALM production into animal and human cell lines (mouse monocytic leukemia: ATCC # CRL- 11771, -11772, -1173, mouse mammary adenocarcinoma: ATCC# CRL-12184, -12185; and human carcinoma of the cervix: ATCC # CRL-12510). The DCE/DALM vectors can be used to tag target cells, detectable by broad-spectrum light absorbance, luminescence, or fluorescence. DCE/DALM can further be activated with light, microwave energy, or by oxidative chemistry to kill the targeted microbes or other cells.

  6. Standardizing Visual Control Devices for Tsetse Flies: East African Species Glossina fuscipes fuscipes and Glossina tachinoides

    PubMed Central

    Oloo, Francis; Sciarretta, Andrea; Kröber, Thomas; McMullin, Andrew; Mihok, Steve; Guerin, Patrick M.

    2014-01-01

    Background Riverine species of tsetse are responsible for most human African trypanosomiasis (HAT) transmission and are also important vectors of animal trypanosomiasis. This study concerns the development of visual control devices for two such species, Glossina fuscipes fuscipes and Glossina tachinoides, at the eastern limits of their continental range. The goal was to determine the most long-lasting, practical and cost-effective visually attractive device that induces the strongest landing responses in these species for use as insecticide-impregnated tools in vector population suppression. Methods and Findings Field trials were conducted in different seasons on G. f. fuscipes in Kenya, Ethiopia and the Sudan and on G. tachinoides in Ethiopia to measure the performance of traps and 2D targets of different sizes and colours, with and without chemical baits, at different population densities and under different environmental conditions. Adhesive film was used to enumerate flies at these remote locations to compare trapping efficiencies. The findings show that targets made from black and blue fabrics (either phthalogen or turquoise) covered with adhesive film render them equal to or more efficient than traps at capturing G. f. fuscipes and G. tachinoides. Biconical trap efficiency varied between 25% and 33% for the two species. Smaller 0.25 m×0.25 m phthalogen blue-black targets proved more efficient than the regular 1 m2 target for both species, by over six times for Glossina f. fuscipes and two times for G. tachinoides based on catches per m2. Overall, targets with a higher edge/surface area ratio were more efficient at capturing flies. Conclusions/Significance Taking into account practical considerations and fly preferences for edges and colours, we propose a 0.5×0.75 m blue-black target as a simple cost-effective device for management of G. f. fuscipes and G. tachinoides, impregnated with insecticide for control and covered with adhesive film for population sampling. PMID:25411931

  7. Dengue Vector Dynamics (Aedes aegypti) Influenced by Climate and Social Factors in Ecuador: Implications for Targeted Control

    PubMed Central

    Stewart Ibarra, Anna M.; Ryan, Sadie J.; Beltrán, Efrain; Mejía, Raúl; Silva, Mercy; Muñoz, Ángel

    2013-01-01

    Background Dengue fever, a mosquito-borne viral disease, is now the fastest spreading tropical disease globally. Previous studies indicate that climate and human behavior interact to influence dengue virus and vector (Aedes aegypti) population dynamics; however, the relative effects of these variables depends on local ecology and social context. We investigated the roles of climate and socio-ecological factors on Ae. aegypti population dynamics in Machala, a city in southern coastal Ecuador where dengue is hyper-endemic. Methods/Principal findings We studied two proximate urban localities where we monitored weekly Ae. aegypti oviposition activity (Nov. 2010-June 2011), conducted seasonal pupal surveys, and surveyed household to identify dengue risk factors. The results of this study provide evidence that Ae. aegypti population dynamics are influenced by social risk factors that vary by season and lagged climate variables that vary by locality. Best-fit models to predict the presence of Ae. aegypti pupae included parameters for household water storage practices, access to piped water, the number of households per property, condition of the house and patio, and knowledge and perceptions of dengue. Rainfall and minimum temperature were significant predictors of oviposition activity, although the effect of rainfall varied by locality due to differences in types of water storage containers. Conclusions These results indicate the potential to reduce the burden of dengue in this region by conducting focused vector control interventions that target high-risk households and containers in each season and by developing predictive models using climate and non-climate information. These findings provide the region's public health sector with key information for conducting time and location-specific vector control campaigns, and highlight the importance of local socio-ecological studies to understand dengue dynamics. See Text S1 for an executive summary in Spanish. PMID:24324542

  8. Vector control improves survival of three species of prairie dogs (Cynomys) in areas considered enzootic for plague.

    PubMed

    Biggins, Dean E; Godbey, Jerry L; Gage, Kenneth L; Carter, Leon G; Montenieri, John A

    2010-01-01

    Plague causes periodic epizootics that decimate populations of prairie dogs (PDs) (Cynomys), but the means by which the causative bacterium (Yersinia pestis) persists between epizootics are poorly understood. Plague epizootics in PDs might arise as the result of introductions of Y. pestis from sources outside PD colonies. However, it remains possible that plague persists in PDs during interepizootic periods and is transmitted at low rates among highly susceptible individuals within and between their colonies. If this is true, application of vector control to reduce flea numbers might reduce mortality among PDs. To test whether vector control enhances PD survival in the absence of obvious plague epizootics, we reduced the numbers of fleas (vectors for Y. pestis) 96-98% (1 month posttreatment) on 15 areas involving three species of PDs (Cynomys leucurus, Cynomys parvidens in Utah, and Cynomys ludovicianus in Montana) during 2000-2004 using deltamethrin dust delivered into burrows as a pulicide. Even during years without epizootic plague, PD survival rates at dusted sites were 31-45% higher for adults and 2-34% higher for juveniles compared to survival rates at nondusted sites. Y. pestis was cultured from 49 of the 851 flea pools tested (6882 total fleas) and antibodies against Y. pestis were identified in serum samples from 40 of 2631 PDs. Although other explanations are possible, including transmission of other potentially fatal pathogens by fleas, ticks, or other ectoparasites, our results suggest that plague might be maintained indefinitely in PD populations in the absence of free epizootics and widespread mortality among these animals. If PDs and their fleas support enzootic cycles of plague transmission, there would be important implications for the conservation of these animals and other species. PMID:20158328

  9. The Importance of Veterinary Policy in Preventing the Emergence and Re-Emergence of Zoonotic Disease: Examining the Case of Human African Trypanosomiasis in Uganda

    PubMed Central

    Okello, Anna L.; Welburn, Susan C.

    2014-01-01

    Rapid changes in human behavior, resource utilization, and other extrinsic environmental factors continue to threaten the current distribution of several endemic and historically neglected zoonoses in many developing regions worldwide. There are numerous examples of zoonotic diseases which have circulated within relatively localized geographical areas for some time, before emerging into new regions as a result of changing human, environmental, or behavioral dynamics. While the world’s focus is currently on the Ebola virus gaining momentum in western Africa, another pertinent example of this phenomenon is zoonotic human African trypanosomiasis (HAT), endemic to south and eastern Africa, and spread via infected cattle. In recent years, the ongoing northwards spread of this disease in the country has posed a serious public health threat to the human population of Uganda, increasing the pressure on both individual families and government services to control the disease. Moreover, the emergence of HAT into new areas of Uganda in recent years exemplifies the important role of veterinary policy in mitigating the severe human health and economic impacts of zoonotic disease. The systemic challenges surrounding the development and enforcement of veterinary policy described here are similar across sub-Saharan Africa, highlighting the necessity to consider and support zoonotic disease control in broader human and animal health systems strengthening and associated development programs on the continent. PMID:25405148

  10. Microbial symbiosis and the control of vector-borne pathogens in tsetse flies, human lice, and triatomine bugs.

    PubMed

    Sassera, Davide; Epis, Sara; Pajoro, Massimo; Bandi, Claudio

    2013-09-01

    Symbiosis is a widespread biological phenomenon, and is particularly common in arthropods. Bloodsucking insects are among the organisms that rely on beneficial bacterial symbionts to complement their unbalanced diet. This review is focused on describing symbiosis, and possible strategies for the symbiont-based control of insects and insect-borne diseases, in three bloodsucking insects of medical importance: the flies of the genus Glossina, the lice of the genus Pediculus, and triatomine bugs of the subfamily Triatominae. Glossina flies are vector of Trypanosoma brucei, the causative agent of sleeping sickness and other pathologies. They are also associated with two distinct bacterial symbionts, the primary symbiont Wigglesworthia spp., and the secondary, culturable symbiont Sodalis glossinidius. The primary symbiont of human lice, Riesia pediculicola, has been shown to be fundamental for the host, due to its capacity to synthesize B-group vitamins. An antisymbiotic approach, with antibiotic treatment targeted on the lice symbionts, could represent an alternative strategy to control these ectoparasites. In the case of triatominae bugs, the genetic modification of their symbiotic Rhodococcus bacteria, for production of anti-Trypanosoma molecules, is an example of paratransgenesis, i.e. the use of symbiotic microorganism engineered in order to reduce the vector competence of the insect host. PMID:24188239

  11. Control algorithm for the inverter fed induction motor drive with DC current feedback loop based on principles of the vector control

    SciTech Connect

    Vuckovic, V.; Vukosavic, S. )

    1992-01-01

    This paper brings out a control algorithm for VSI fed induction motor drives based on the converter DC link current feedback. It is shown that the speed and flux can be controlled over the wide speed and load range quite satisfactorily for simpler drives. The base commands of both the inverter voltage and frequency are proportional to the reference speed, but each of them is further modified by the signals derived from the DC current sensor. The algorithm is based on the equations well known from the vector control theory, and is aimed to obtain the constant rotor flux and proportionality between the electrical torque, the slip frequency and the active component of the stator current. In this way, the problems of slip compensation, Ri compensation and correction of U/f characteristics are solved in the same time. Analytical considerations and computer simulations of the proposed control structure are in close agreement with the experimental results measured on a prototype drive.

  12. Preliminary Characterization of the Altair Lunar Lander Slosh Dynamics and Some Implications for the Thrust Vector Control Design

    NASA Technical Reports Server (NTRS)

    Lee, Allan Y.; Strahan, Alan; Tanimoto, Rebekah; Casillas, Arturo

    2010-01-01

    This paper describes a conceptual design of the Thrust Vector Control (TVC) system and preliminary modeling of propellant slosh, for the Altair Lunar Lander. Altair is a vehicle element of the NASA Constellation Program aimed at returning humans to the moon. Guidance, Navigation, and Control (GN&C) is the measurement and control of spacecraft position, velocity, and attitude in support of mission objectives. One key GN&C function is the commanding of effectors that control attitude and impart delta V on the vehicle, utilizing both reaction control system (RCS) thrusters and throttling and TVC gimbaling of the vehicle main engine. Both the Altair descent and ascent modules carry fuel tanks. During thrusting maneuvers, the sloshing of liquid fuels in partially filled tanks can interact with the controlled system in such a way as to cause the overall system to be unstable. These fuel tanks must be properly placed, relative to the spacecraft's c.m., to avoid any unstable interactions. Following this will be a discussion of propellant slosh modeling work performed for the present vehicle configuration, including slosh frequency and participatory fluid mass predictions. Knowing the range of slosh mode frequencies over mission phases, the TVC bandwidth must be carefully selected so as not to excite the slosh modes at those frequencies. The likely need to increase the damping factor of slosh modes via baffles will also be discussed. To conclude, a discussion of operations procedures aimed at minimizing TVC-slosh interactions will be given.

  13. Modified vector control algorithm for increasing partial-load efficiency of fractional-slot concentrated-winding surface PM machines

    SciTech Connect

    El-Refaie, Ayman M; Jahns, Thomas M; Reddy, Patel; McKeever, John W

    2006-01-01

    This paper presents a modified vector control algorithm for a fractional-slot concentrated-winding surface PM machine that has been developed to maximize the machine's partial-load efficiency over a wide range of operating conditions. By increasing the amplitude of the negative d-axis current, the resulting increase in the stator copper losses can be more than offset by the reduction in the iron core losses achieved by lowering the stator d-axis flux amplitude. The effectiveness of this technique has been demonstrated using both analytical models and finite element analysis (FEA) for a 55 kW (peak) surface PM machine design developed for a demanding set of traction drive performance requirements. For this example, the modified control strategy increases the partial-load efficiency at 20% of rated torque by >6% at 2000 rpm compared to the maximum torque/amp algorithm, making the machine much more attractive for its intended application

  14. Modified vector control algorithm for increasing partial-load efficiency of fractional-slot concentrated-winding surface PM machines

    SciTech Connect

    El-Refaie, Ayman M; Jahns, Thomas M; Reddy, Patel; McKeever, John W

    2008-01-01

    This paper presents a modified vector control algorithm for a fractional-slot concentrated-winding surface permanent magnet (SPM) machine that has been developed to maximize the machine's partial-load efficiency over a wide range of operating conditions. By increasing the amplitude of the negative d-axis current, the resulting increase in the stator copper losses can be more than offset by the reduction in the iron core losses achieved by lowering the stator d-axis flux amplitude. The effectiveness of this technique has been demonstrated using both analytical models and finite element analysis for a 55-kW (peak) SPM machine design developed for a demanding set of traction drive performance requirements. For this example, the modified control strategy increases the partial-load efficiency at 20% of rated torque by > 6% at 2000 r/min compared to the maximum torque/ampere algorithm, making the machine much more attractive for its intended application.

  15. VECTOR CONTROL, PEST MANAGEMENT, RESISTANCE, REPELLENTS Sublethal Effects of Metarhizium anisopliae (Deuteromycetes) on

    E-print Network

    mass) in all active I. scapularis stages and indicates that its impact as a biocontrol agent might- native, biological control agents, such as ento- mopathogenic fungi (Zhioua et al. 1997, 1999a; Ben) and controls quest- ing adults (Benjamin et al. 2002). For I. scapularis, effectiveness of control agents

  16. A Noether Theorem on Unimprovable Conservation Laws for Vector-Valued Optimization Problems in Control Theory

    E-print Network

    Delfim F. M. Torres

    2004-11-08

    We obtain a version of Noether's invariance theorem for optimal control problems with a finite number of cost functionals. The result is obtained by formulating E. Noether's result to optimal control problems subject to isoperimetric constraints, and then using the unimprovable (Pareto) notion of optimality. A result of this kind was posed to the author, as a mathematical open question, of great interest in applications of control engineering, by A. Gugushvili.

  17. Novel azasterols as potential agents for treatment of leishmaniasis and trypanosomiasis.

    PubMed

    Lorente, Silvia Orenes; Rodrigues, Juliany C F; Jiménez Jiménez, Carmen; Joyce-Menekse, Miranda; Rodrigues, Carlos; Croft, Simon L; Yardley, Vanessa; de Luca-Fradley, Kate; Ruiz-Pérez, Luis M; Urbina, Julio; de Souza, Wanderley; González Pacanowska, Dolores; Gilbert, Ian H

    2004-08-01

    This paper describes the design and evaluation of novel azasterols as potential compounds for the treatment of leishmaniasis and other diseases caused by trypanosomatid parasites. Azasterols are a known class of (S)-adenosyl-L-methionine: Delta24-sterol methyltransferase(24-SMT) inhibitors in fungi, plants, and some parasitic protozoa. The compounds prepared showed activity at micromolar and nanomolar concentrations when tested against Leishmania spp. and Trypanosoma spp. The enzymatic and sterol composition studies indicated that the most active compounds acted by inhibiting 24-SMT. The role of the free hydroxyl group at position 3 of the sterol nucleus was also probed. When an acetate was attached to the 3beta-OH, the compounds did not inhibit the enzyme but had an effect on parasite growth and the levels of sterols in the parasite, suggesting that the acetate group was removed in the organism. Thus, an acetate group on the 3beta-OH may have application as a prodrug. However, there may be an additional mode(s) of action for these acetate derivatives. These compounds were shown to have ultrastructural effects on Leishmania amazonensis promastigote membranes, including the plasma membrane, the mitochondrial membrane, and the endoplasmic reticulum. The compounds were also found to be active against the bloodstream form (trypomastigotes) of Trypanosoma brucei rhodesiense, a causative agent of African trypanosomiasis. PMID:15273104

  18. Direct Blood Dry LAMP: A Rapid, Stable, and Easy Diagnostic Tool for Human African Trypanosomiasis

    PubMed Central

    Hayashida, Kyoko; Kajino, Kiichi; Hachaambwa, Lottie; Namangala, Boniface; Sugimoto, Chihiro

    2015-01-01

    Loop-mediated isothermal amplification (LAMP) is a rapid and sensitive tool used for the diagnosis of a variety of infectious diseases. One of the advantages of this method over the polymerase chain reaction is that DNA amplification occurs at a constant temperature, usually between 60–65°C; therefore, expensive devices are unnecessary for this step. However, LAMP still requires complicated sample preparation steps and a well-equipped laboratory to produce reliable and reproducible results, which limits its use in resource-poor laboratories in most developing countries. In this study, we made several substantial modifications to the technique to carry out on-site diagnosis of Human African Trypanosomiasis (HAT) in remote areas using LAMP. The first essential improvement was that LAMP reagents were dried and stabilized in a single tube by incorporating trehalose as a cryoprotectant to prolong shelf life at ambient temperature. The second technical improvement was achieved by simplifying the sample preparation step so that DNA or RNA could be amplified directly from detergent-lysed blood samples. With these modifications, diagnosis of HAT in local clinics or villages in endemic areas becomes a reality, which could greatly impact on the application of diagnosis not only for HAT but also for other tropical diseases. PMID:25769046

  19. Characterization of a Melamino Nitroheterocycle as a Potential Lead for the Treatment of Human African Trypanosomiasis

    PubMed Central

    Giordani, Federica; Buschini, Annamaria; Baliani, Alessandro; Kaiser, Marcel; Brun, Reto; Barrett, Michael P.; Pellacani, Claudia; Poli, Paola

    2014-01-01

    This paper reports an evaluation of a melamino nitroheterocycle, a potential lead for further development as an agent against human African trypanosomiasis (HAT). Studies on its efficacy, physicochemical and biopharmaceutical properties, and potential for toxicity are described. The compound previously had been shown to possess exceptional activity against Trypanosoma brucei in in vitro assays comparable to that of melarsoprol. Here, we demonstrate that the compound also was curative in the stringent acute mouse model T. brucei rhodesiense STIB 900 when given intraperitoneally at 40 mg/kg of body weight. Nevertheless, activity was only moderate when the oral route was used, and no cure was obtained when the compound was tested in a stage 2 rodent model of infection. Genotoxic profiling revealed that the compound induces DNA damage by a mechanism apparently independent from nitroreduction and involving the introduction of base pair substitutions (Ames test), possibly caused by oxidative damage of the DNA (comet test). No significant genotoxicity was observed at the chromosome level (micronucleus assay). The lack of suitable properties for oral and central nervous system uptake and the genotoxic liabilities prevent the progression of this melamine nitroheterocycle as a drug candidate for HAT. Further modification of the compound is required to improve the pharmacokinetic properties of the molecule and to separate the trypanocidal activity from the toxic potential. PMID:25022590

  20. Development of multiplex serological assay for the detection of human African trypanosomiasis.

    PubMed

    Nzou, Samson Muuo; Fujii, Yoshito; Miura, Masashi; Mwau, Matilu; Mwangi, Anne Wanjiru; Itoh, Makoto; Salam, Md Abdus; Hamano, Shinjiro; Hirayama, Kenji; Kaneko, Satoshi

    2016-04-01

    Human African trypanosomiasis (HAT) is a disease caused by Kinetoplastid infection. Serological tests are useful for epidemiological surveillance. The aim of this study was to develop a multiplex serological assay for HAT to assess the diagnostic value of selected HAT antigens for sero-epidemiological surveillance. We cloned loci encoding eight antigens from Trypanosoma brucei gambiense, expressed the genes in bacterial systems, and purified the resulting proteins. Antigens were subjected to Luminex multiplex assays using sera from HAT and VL patients to assess the antigens' immunodiagnostic potential. Among T. b. gambiense antigens, the 64-kDa and 65-kDa invariant surface glycoproteins (ISGs) and flagellar calcium binding protein (FCaBP) had high sensitivity for sera from T. b. gambiense patients, yielding AUC values of 0.871, 0.737 and 0.858 respectively in receiver operating characteristics (ROC) analysis. The ISG64, ISG65, and FCaBP antigens were partially cross-reactive to sera from Trypanosoma brucei rhodesiense patients. The GM6 antigen was cross-reactive to sera from T. b. rhodesiense patients as well as to sera from VL patients. Furthermore, heterogeneous antibody responses to each individual HAT antigen were observed. Testing for multiple HAT antigens in the same panel allowed specific and sensitive detection. Our results demonstrate the utility of applying multiplex assays for development and evaluation of HAT antigens for use in sero-epidemiological surveillance. PMID:26519611

  1. Evaluation of histone deacetylase inhibitors (HDACi) as therapeutic leads for human African trypanosomiasis (HAT).

    PubMed

    Carrillo, Angela K; Guiguemde, W Armand; Guy, R Kiplin

    2015-08-15

    Two of the histone deacetylases, TbDAC1 and TbDAC3, have been reported to be essential genes in trypanosomes. Therefore, we tested the activity of a panel of human histone deacetylase inhibitors (HDACi) for their ability to block proliferation of Trypanosoma brucei brucei. Among the HDACi's, the hydroxamic acid derivatives panobinostat and belinostat exhibited potency that appeared to make them viable candidates for development due to their reported pharmacokinetic characteristics. However, cellular pharmacodynamic analysis demonstrated that these drugs were unable to kill cultured parasites at exposures seen in patients at their tolerated doses and additionally failed to show any synergistic effects in combination with pentamidine, suramin, melarsoprol, or nifurtimox. Analysis of the potency of the entire HDACi panel revealed no correlations between potency against any human HDAC isoform and inhibition of T. brucei proliferation, suggesting that the trypanosome histone deacetylases possess a unique specificity. These studies confirmed that HDAC inhibitors have potential as leads against human African trypanosomiasis but that none of the current clinical candidates can be directly repurposed. Therefore, development of HDACi's with appropriate specificity and potency may be a viable route to a new class of anti-trypanosomal drugs. PMID:25637120

  2. Key Source Habitats and Potential Dispersal of Triatoma infestans Populations in Northwestern Argentina: Implications for Vector Control

    PubMed Central

    Gürtler, Ricardo E.; Cecere, María C.; Fernández, María del Pilar; Vazquez-Prokopec, Gonzalo M.; Ceballos, Leonardo A.; Gurevitz, Juan M.; Kitron, Uriel; Cohen, Joel E.

    2014-01-01

    Background Triatoma infestans —the principal vector of the infection that causes Chagas disease— defies elimination efforts in the Gran Chaco region. This study identifies the types of human-made or -used structures that are key sources of these bugs in the initial stages of house reinfestation after an insecticide spraying campaign. Methodology and Principal Findings We measured demographic and blood-feeding parameters at two geographic scales in 11 rural communities in Figueroa, northwest Argentina. Of 1,297 sites searched in spring, 279 (21.5%) were infested. Bug abundance per site and female fecundity differed significantly among habitat types (ecotopes) and were highly aggregated. Domiciles (human sleeping quarters) had maximum infestation prevalence (38.7%), human-feeding bugs and total egg production, with submaximal values for other demographic and blood-feeding attributes. Taken collectively peridomestic sites were three times more often infested than domiciles. Chicken coops had greater bug abundance, blood-feeding rates, engorgement status, and female fecundity than pig and goat corrals. The host-feeding patterns were spatially structured yet there was strong evidence of active dispersal of late-stage bugs between ecotopes. Two flight indices predicted that female fliers were more likely to originate from kitchens and domiciles, rejecting our initial hypothesis that goat and pig corrals would dominate. Conclusions and Significance Chicken coops and domiciles were key source habitats fueling rapid house reinfestation. Focusing control efforts on ecotopes with human-fed bugs (domiciles, storerooms, goat corrals) would neither eliminate the substantial contributions to bug population growth from kitchens, chicken coops, and pig corrals nor stop dispersal of adult female bugs from kitchens. Rather, comprehensive control of the linked network of ecotopes is required to prevent feeding on humans, bug population growth, and bug dispersal simultaneously. Our study illustrates a demographic approach that may be applied to other regions and triatomine species for the design of innovative, improved vector control strategies. PMID:25299653

  3. International network for capacity building for the control of emerging viral vector-borne zoonotic diseases: ARBO-ZOONET.

    PubMed

    Ahmed, J; Bouloy, M; Ergonul, O; Fooks, Ar; Paweska, J; Chevalier, V; Drosten, C; Moormann, R; Tordo, N; Vatansever, Z; Calistri, P; Estrada-Pena, A; Mirazimi, A; Unger, H; Yin, H; Seitzer, U

    2009-03-26

    Arboviruses are arthropod-borne viruses, which include West Nile fever virus (WNFV), a mosquito-borne virus, Rift Valley fever virus (RVFV), a mosquito-borne virus, and Crimean-Congo haemorrhagic fever virus (CCHFV), a tick-borne virus. These arthropod-borne viruses can cause disease in different domestic and wild animals and in humans, posing a threat to public health because of their epidemic and zoonotic potential. In recent decades, the geographical distribution of these diseases has expanded. Outbreaks of WNF have already occurred in Europe, especially in the Mediterranean basin. Moreover, CCHF is endemic in many European countries and serious outbreaks have occurred, particularly in the Balkans, Turkey and Southern Federal Districts of Russia. In 2000, RVF was reported for the first time outside the African continent, with cases being confirmed in Saudi Arabia and Yemen. This spread was probably caused by ruminant trade and highlights that there is a threat of expansion of the virus into other parts of Asia and Europe. In the light of global warming and globalisation of trade and travel, public interest in emerging zoonotic diseases has increased. This is especially evident regarding the geographical spread of vector-borne diseases. A multi-disciplinary approach is now imperative, and groups need to collaborate in an integrated manner that includes vector control, vaccination programmes, improved therapy strategies, diagnostic tools and surveillance, public awareness, capacity building and improvement of infrastructure in endemic regions. PMID:19341603

  4. Optimal control of a universal rotating magnetic vector for petal-shaped capsule robot in curve environment

    NASA Astrophysics Data System (ADS)

    Zhang, Yongshun; Bai, Jianwei; Chi, Minglu; Cheng, Cunxin; Wang, Dianlong

    2014-09-01

    Steering control of a capsule robot in curve environment by magnetic navigation is not yet solved completely. A petal-shaped capsule robot with less steering resistance based on multiple wedge effects is presented, and an optimization method with two processes for determining the orientation of a pre-applied universal magnetic spin vector is proposed. To realize quick and non-contact steering swimming, a fuzzy comprehensive evaluation method for optimizing the steering driving angle is presented based on two evaluation indexes including the average steering speed and the average steering trajectory deviation, achieving the initial optimal orientation of a universal magnetic spin vector. To further reduce robotic magnetic vibration, a main target method for optimizing its final orientation, which is used for fine adjustment, is employed under the constrains of the magnetic moments. Swimming experimental results in curve pipe verified the effectiveness of the optimization method, which can be effectively used to realize non-contact steering swimming of the petal-shaped robot and reduce its vibration.

  5. Dopamine Receptor Antagonists as New Mode-of-Action Insecticide Leads for Control of Aedes and Culex Mosquito Vectors

    PubMed Central

    Nuss, Andrew B.; Ejendal, Karin F. K.; Doyle, Trevor B.; Meyer, Jason M.; Lang, Emma G.; Watts, Val J.; Hill, Catherine A.

    2015-01-01

    Background New mode-of-action insecticides are sought to provide continued control of pesticide resistant arthropod vectors of neglected tropical diseases (NTDs). We previously identified antagonists of the AaDOP2 D1-like dopamine receptor (DAR) from the yellow fever mosquito, Aedes aegypti, with toxicity to Ae. aegypti larvae as leads for novel insecticides. To extend DAR-based insecticide discovery, we evaluated the molecular and pharmacological characteristics of an orthologous DAR target, CqDOP2, from Culex quinquefasciatus, the vector of lymphatic filariasis and West Nile virus. Methods/Results CqDOP2 has 94.7% amino acid identity to AaDOP2 and 28.3% identity to the human D1-like DAR, hD1. CqDOP2 and AaDOP2 exhibited similar pharmacological responses to biogenic amines and DAR antagonists in cell-based assays. The antagonists amitriptyline, amperozide, asenapine, chlorpromazine and doxepin were between 35 to 227-fold more selective at inhibiting the response of CqDOP2 and AaDOP2 in comparison to hD1. Antagonists were toxic to both C. quinquefasciatus and Ae. aegypti larvae, with LC50 values ranging from 41 to 208 ?M 72 h post-exposure. Orthologous DOP2 receptors identified from the African malaria mosquito, Anopheles gambiae, the sand fly, Phlebotomus papatasi and the tsetse fly, Glossina morsitans, had high sequence similarity to CqDOP2 and AaDOP2. Conclusions DAR antagonists represent a putative new insecticide class with activity against C. quinquefasciatus and Ae. aegypti, the two most important mosquito vectors of NTDs. There has been limited change in the sequence and pharmacological properties of the DOP2 DARs of these species since divergence of the tribes Culicini and Aedini. We identified antagonists selective for mosquito versus human DARs and observed a correlation between DAR pharmacology and the in vivo larval toxicity of antagonists. These data demonstrate that sequence similarity can be predictive of target potential. On this basis, we propose expanded insecticide discovery around orthologous DOP2 targets from additional dipteran vectors. PMID:25793586

  6. Flight-Determined Subsonic Longitudinal Stability and Control Derivatives of the F-18 High Angle of Attack Research Vehicle (HARV) with Thrust Vectoring

    NASA Technical Reports Server (NTRS)

    Iliff, Kenneth W.; Wang, Kon-Sheng Charles

    1997-01-01

    The subsonic longitudinal stability and control derivatives of the F-18 High Angle of Attack Research Vehicle (HARV) are extracted from dynamic flight data using a maximum likelihood parameter identification technique. The technique uses the linearized aircraft equations of motion in their continuous/discrete form and accounts for state and measurement noise as well as thrust-vectoring effects. State noise is used to model the uncommanded forcing function caused by unsteady aerodynamics over the aircraft, particularly at high angles of attack. Thrust vectoring was implemented using electrohydraulically-actuated nozzle postexit vanes and a specialized research flight control system. During maneuvers, a control system feature provided independent aerodynamic control surface inputs and independent thrust-vectoring vane inputs, thereby eliminating correlations between the aircraft states and controls. Substantial variations in control excitation and dynamic response were exhibited for maneuvers conducted at different angles of attack. Opposing vane interactions caused most thrust-vectoring inputs to experience some exhaust plume interference and thus reduced effectiveness. The estimated stability and control derivatives are plotted, and a discussion relates them to predicted values and maneuver quality.

  7. A Randomized Longitudinal Factorial Design to Assess Malaria Vector Control and Disease Management Interventions in Rural Tanzania

    PubMed Central

    Kramer, Randall A.; Mboera, Leonard E. G.; Senkoro, Kesheni; Lesser, Adriane; Shayo, Elizabeth H.; Paul, Christopher J.; Miranda, Marie Lynn

    2014-01-01

    The optimization of malaria control strategies is complicated by constraints posed by local health systems, infrastructure, limited resources, and the complex interactions between infection, disease, and treatment. The purpose of this paper is to describe the protocol of a randomized factorial study designed to address this research gap. This project will evaluate two malaria control interventions in Mvomero District, Tanzania: (1) a disease management strategy involving early detection and treatment by community health workers using rapid diagnostic technology; and (2) vector control through community-supported larviciding. Six study villages were assigned to each of four groups (control, early detection and treatment, larviciding, and early detection and treatment plus larviciding). The primary endpoint of interest was change in malaria infection prevalence across the intervention groups measured during annual longitudinal cross-sectional surveys. Recurring entomological surveying, household surveying, and focus group discussions will provide additional valuable insights. At baseline, 962 households across all 24 villages participated in a household survey; 2,884 members from 720 of these households participated in subsequent malariometric surveying. The study design will allow us to estimate the effect sizes of different intervention mixtures. Careful documentation of our study protocol may also serve other researchers designing field-based intervention trials. PMID:24840349

  8. A randomized longitudinal factorial design to assess malaria vector control and disease management interventions in rural Tanzania.

    PubMed

    Kramer, Randall A; Mboera, Leonard E G; Senkoro, Kesheni; Lesser, Adriane; Shayo, Elizabeth H; Paul, Christopher J; Miranda, Marie Lynn

    2014-05-01

    The optimization of malaria control strategies is complicated by constraints posed by local health systems, infrastructure, limited resources, and the complex interactions between infection, disease, and treatment. The purpose of this paper is to describe the protocol of a randomized factorial study designed to address this research gap. This project will evaluate two malaria control interventions in Mvomero District, Tanzania: (1) a disease management strategy involving early detection and treatment by community health workers using rapid diagnostic technology; and (2) vector control through community-supported larviciding. Six study villages were assigned to each of four groups (control, early detection and treatment, larviciding, and early detection and treatment plus larviciding). The primary endpoint of interest was change in malaria infection prevalence across the intervention groups measured during annual longitudinal cross-sectional surveys. Recurring entomological surveying, household surveying, and focus group discussions will provide additional valuable insights. At baseline, 962 households across all 24 villages participated in a household survey; 2,884 members from 720 of these households participated in subsequent malariometric surveying. The study design will allow us to estimate the effect sizes of different intervention mixtures. Careful documentation of our study protocol may also serve other researchers designing field-based intervention trials. PMID:24840349

  9. Construction and evaluation of pMycoFos, a fosmid shuttle vector for Mycobacterium spp. with inducible gene expression and copy number control.

    PubMed

    Ly, Mai Anh; Liew, Elissa F; Le, Nga B; Coleman, Nicholas V

    2011-09-01

    Molecular tools for Gram-positive bacteria such as Mycobacterium are less well-developed than those for Gram-negatives such as Escherichiacoli. This has slowed the molecular-genetic characterisation of Mycobacterium spp, which is unfortunate, since this genus has high medical, environmental and industrial significance. Here, we developed a new Mycobacterium shuttle vector (pMycoFos, 12.5kb, Km(R)) which combines desirable features of several previous vectors (controllable copy number in E. coli, inducible gene expression in Mycobacterium) and provides a new multiple cloning site compatible with large inserts of high-GC content DNA. Copy number control in E. coli was confirmed by the increased Km(R) of cultures after arabinose induction and the greater DNA yield of vector from arabinose-induced cultures. Measurement of beta-galactosidase activity in pMycoFos clones carrying the lacZ gene showed that in Mycobacterium smegmatis mc(2)-155, expression was inducible by acetamide, but in E. coli EPI300, the expression level was primarily determined by the vector copy number. Examination of protein profiles on SDS-PAGE gels confirmed the beta-galactosidase assay results. Construction of a fosmid library with the new vector confirmed that it could carry large DNA inserts. The new vector enabled the stable cloning and expression of an ethene monooxygenase gene cluster, which had eluded previous attempts at heterologous expression. PMID:21689690

  10. S argassum muticum-synthesized silver nanoparticles: an effective control tool against mosquito vectors and bacterial pathogens.

    PubMed

    Madhiyazhagan, Pari; Murugan, Kadarkarai; Kumar, Arjunan Naresh; Nataraj, Thiyagarajan; Dinesh, Devakumar; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Mahesh Kumar, Palanisamy; Suresh, Udaiyan; Roni, Mathath; Nicoletti, Marcello; Alarfaj, Abdullah A; Higuchi, Akon; Munusamy, Murugan A; Benelli, Giovanni

    2015-11-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. Furthermore, pathogens and parasites polluting water also constitute a severe plague for populations of developing countries. In this research, silver nanoparticles (AgNP) were synthesized using the aqueous extract of the seaweed Sargassum muticum. The production of AgNP was confirmed by surface plasmon resonance band illustrated in UV-vis spectrophotometry. AgNP were characterized by FTIR, SEM, EDX, and XRD analyses. AgNP were mostly spherical in shape, crystalline in nature, with face-centered cubic geometry, and mean size was 43-79 nm. Toxicity of AgNP was assessed against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. In laboratory, AgNP were highly toxic against larvae and pupae of the three mosquito species. Maximum efficacy was observed against A. stephensi larvae, with LC50 ranging from 16.156 ppm (larva I) to 28.881 ppm (pupa). In the field, a single treatment with AgNP (10?×?LC50) in water storage reservoirs was effective against the three mosquito vectors, allowing complete elimination of larval populations after 72 h. In ovicidal experiments, egg hatchability was reduced by 100% after treatment with 30 ppm of AgNP. Ovideterrence assays highlighted that 10 ppm of AgNP reduced oviposition rates of more than 70% in A. aegypti, A. stephensi, and C. quinquefasciatus (OAI?=?-0.61, -0.63, and -0.58, respectively). Antibacterial properties of AgNP were evaluated against Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi using the agar disk diffusion and minimum inhibitory concentration protocol. AgNP tested at 50 ppm evoked growth inhibition zones larger than 5 mm in all tested bacteria. Overall, the chance to use S. muticum-synthesized AgNP for control of mosquito vectors seems promising since they are effective at low doses and may constitute an advantageous alternative to build newer and safer mosquito control tools. This is the first report about ovicidal activity of metal nanoparticles against mosquito vectors. PMID:26281786

  11. Design Specification for a Thrust-Vectoring, Actuated-Nose-Strake Flight Control Law for the High-Alpha Research Vehicle

    NASA Technical Reports Server (NTRS)

    Bacon, Barton J.; Carzoo, Susan W.; Davidson, John B.; Hoffler, Keith D.; Lallman, Frederick J.; Messina, Michael D.; Murphy, Patrick C.; Ostroff, Aaron J.; Proffitt, Melissa S.; Yeager, Jessie C.; Foster, John V.; Bundick, W. Thomas; Connelly, Patrick J.; Kelly, John W.; Pahle, Joseph W.; Thomas, Michael; Wichman, Keith D.; Wilson, R. Joseph

    1996-01-01

    Specifications for a flight control law are delineated in sufficient detail to support coding the control law in flight software. This control law was designed for implementation and flight test on the High-Alpha Research Vehicle (HARV), which is an F/A-18 aircraft modified to include an experimental multi-axis thrust-vectoring system and actuated nose strakes for enhanced rolling (ANSER). The control law, known as the HARV ANSER Control Law, was designed to utilize a blend of conventional aerodynamic control effectors, thrust vectoring, and actuated nose strakes to provide increased agility and good handling qualities throughout the HARV flight envelope, including angles of attack up to 70 degrees.

  12. Insecticide resistance in Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and Anopheles gambiae Giles (Diptera: Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa.

    PubMed

    Gnankiné, Olivier; Bassolé, Imael H N; Chandre, Fabrice; Glitho, Isabelle; Akogbeto, Martin; Dabiré, Roch K; Martin, Thibaud

    2013-10-01

    Insecticides from the organophosphate (OP) and pyrethroid (PY) chemical families, have respectively, been in use for 50 and 30 years in West Africa, mainly against agricultural pests, but also against vectors of human disease. The selection pressure, with practically the same molecules year after year (mainly on cotton), has caused insecticide resistance in pest populations such as Bemisia tabaci, vector of harmful phytoviruses on vegetables. The evolution toward insecticide resistance in malaria vectors such as Anopheles gambiae sensus lato (s.l.) is probably related to the current use of these insecticides in agriculture. Thus, successful pest and vector control in West Africa requires an investigation of insect susceptibility, in relation to the identification of species and sub species, such as molecular forms or biotypes. Identification of knock down resistance (kdr) and acetylcholinesterase gene (Ace1) mutations modifying insecticide targets in individual insects and measure of enzymes activity typically involved in insecticide metabolism (oxidase, esterase and glutathion-S-transferase) are indispensable in understanding the mechanisms of resistance. Insecticide resistance is a good example in which genotype-phenotype links have been made successfully. Insecticides used in agriculture continue to select new resistant populations of B. tabaci that could be from different biotype vectors of plant viruses. As well, the evolution of insecticide resistance in An. gambiae threatens the management of malaria vectors in West Africa. It raises the question of priority in the use of insecticides in health and/or agriculture, and more generally, the question of sustainability of crop protection and vector control strategies in the region. Here, we review the susceptibility tests, biochemical and molecular assays data for B. tabaci, a major pest in cotton and vegetable crops, and An. gambiae, main vector of malaria. The data reviewed was collected in Benin and Burkina Faso between 2008 and 2010 under the Corus 6015 research program. This review aims to show: (i) the insecticide resistance in B. tabaci as well as in An. gambiae; and (ii) due to this, the impact of selection of resistant populations on malaria vector control strategies. Some measures that could be beneficial for crop protection and vector control strategies in West Africa are proposed. PMID:23792227

  13. The fog of war: why the environmental crusade for anadromous fish species in California could disarm the state's local vector control districts in their war against mosquitoes.

    PubMed

    Siptroth, Stephen M; Shanahan, Richard P

    2011-12-01

    In California, local mosquito and vector control districts have successfully controlled mosquito and vector-borne diseases by improving drainage patterns and applying pesticides. The Bay-Delta Conservation Plan, which is a proposed habitat conservation plan for the Sacramento-San Joaquin Bay-Delta estuary, proposes to add over 70,000 acres of habitat in the Delta to improve conditions for threatened and endangered aquatic and terrestrial species. This habitat could also be a suitable mosquito breeding habitat, which will be located in close proximity to urban and suburban communities. Wetland management practices and continued pesticide applications in the Delta could mitigate the effects of a new mosquito breeding habitat. Recent legal developments, however, require districts to obtain and comply with Clean Water Act permits, which restrict the application of pesticides in or near waters of the United States. Moreover, the U.S. Environmental Protection Agency has taken the first step in a rulemaking process that could further limit or prohibit the use of certain vector control pesticides in the Delta. In the near term and until less harmful methods for mosquito control are available, local vector control districts' application of mosquito control pesticides should be exempt from Clean Water Act permit requirements. PMID:23856372

  14. Spatial Orientation and Balance Control Changes Induced by Altered Gravito-Inertial Force Vectors

    NASA Technical Reports Server (NTRS)

    Kaufman, Galen D.; Wood, Scott J.; Gianna, Claire C.; Black, F. Owen; Paloski, William H.; Dawson, David L. (Technical Monitor)

    1999-01-01

    Seventeen healthy and eight vestibular deficient subjects were exposed to an interaural centripetal acceleration of 1 G (resultant 45 deg roll tilt of 1.4 G) on a 0.8 meter radius centrifuge for a period of 90 minutes in the dark. The subjects sat with head fixed upright, except every 4 of 10 minutes when instructed to rotate their head so that their nose and eyes pointed towards a visual point switched on every 3 to 5 seconds at random places (within +/- 30 deg) in the Earth horizontal plane. Motion sickness caused some subjects to limit their head movements during significant portions of the 90 minute period, and led three normal subjects to stop the test earlier. Eye movements, including directed saccades for subjective Earth- and head-referenced planes, were recorded before, during, and immediately after centrifugation using electro-oculography. Postural stability measurements were made before and within ten minutes after centrifugation. In normal subjects, postural sway and multisegment body kinematics were gathered during an eyes-closed head movement cadence (sway-referenced support platform), and in response to translational/rotational platform perturbations. A significant increase in postural sway, segmental motion amplitude and hip frequency was observed after centrifugation. This effect was short-lived, with a recovery time of several postural test trials. There were also asymmetries in the direction of post-centrifugation center of sway and head tilt which depended on the subject's orientation during the centrifugation adaptation period (left ear or right ear out). To delineate the effect of the magnitude of the gravito-inertial vector versus its direction during the adaptive centrifugation period, we tilted eight normal subjects in the roll axis at a 45 deg angle in the dark for 90 minutes without rotational motion. Their postural responses did not change following the period of tilt. Based on verbal reports, normal subjects overestimated roll-tilt during 90 minutes of both tilt and centrifugation stimuli. Subjective estimates of head-horizontal, provided by directed saccades, revealed significant errors after approximately 30 minutes that tended to increase only in the group who underwent centrifugation. Immediately after centrifugation, subjects reported feeling tilted on average 10 degrees in the opposite direction, which was in agreement with the direction of their earth-directed saccades. In vestibular deficient (VD) subjects, postural sway was measured using a sway-referenced or earth-fixed support surface, and with or without a head movement sequence. 'Me protocol was selected for each patient during baseline testing, and corresponded to the most challenging condition in which the patient was able to maintain balance with eyes closed. Bilaterally VD subjects showed no postural decrement after centrifugation, while unilateral VD subjects had varying degrees of decrement. Unilateral VD subjects were tested twice; they underwent centrifugation both with right ear out and left ear out. Their post-centrifuation center of sway shifted at right angles depending on the centrifuge GIF orientation. Bilateral VD subjects bad shifts as well, but no consistent directional trend. VD subjects underestimated roll-tilt during centrifugation, These results suggest that orientation of the gravito-inertial vector and its magnitude arc both used by the central nervous system for calibration of multiple orientation systems. A change in the background gravito-inertial force (otolith input) can rapidly initiate postural and perceptual adaptation in several sensorimotor systems, independent of a structured visual surround.

  15. Pattern Recognition Application of Support Vector Machine for Fault Classification of Thyristor Controlled Series Compensated Transmission Lines

    NASA Astrophysics Data System (ADS)

    Yashvantrai Vyas, Bhargav; Maheshwari, Rudra Prakash; Das, Biswarup

    2015-10-01

    Application of series compensation in extra high voltage (EHV) transmission line makes the protection job difficult for engineers, due to alteration in system parameters and measurements. The problem amplifies with inclusion of electronically controlled compensation like thyristor controlled series compensation (TCSC) as it produce harmonics and rapid change in system parameters during fault associated with TCSC control. This paper presents a pattern recognition based fault type identification approach with support vector machine. The scheme uses only half cycle post fault data of three phase currents to accomplish the task. The change in current signal features during fault has been considered as discriminatory measure. The developed scheme in this paper is tested over a large set of fault data with variation in system and fault parameters. These fault cases have been generated with PSCAD/EMTDC on a 400 kV, 300 km transmission line model. The developed algorithm has proved better for implementation on TCSC compensated line with its improved accuracy and speed.

  16. Made-to-measure malaria vector control strategies: rational design based on insecticide properties and coverage of blood resources for mosquitoes

    PubMed Central

    2014-01-01

    Eliminating malaria from highly endemic settings will require unprecedented levels of vector control. To suppress mosquito populations, vector control products targeting their blood hosts must attain high biological coverage of all available sources, rather than merely high demographic coverage of a targeted resource subset, such as humans while asleep indoors. Beyond defining biological coverage in a measurable way, the proportion of blood meals obtained from humans and the proportion of bites upon unprotected humans occurring indoors also suggest optimal target product profiles for delivering insecticides to humans or livestock. For vectors that feed only occasionally upon humans, preferred animal hosts may be optimal targets for mosquito-toxic insecticides, and vapour-phase insecticides optimized to maximize repellency, rather than toxicity, may be ideal for directly protecting people against indoor and outdoor exposure. However, for vectors that primarily feed upon people, repellent vapour-phase insecticides may be inferior to toxic ones and may undermine the impact of contact insecticides applied to human sleeping spaces, houses or clothing if combined in the same time and place. These concepts are also applicable to other mosquito-borne anthroponoses so that diverse target species could be simultaneously controlled with integrated vector management programmes. Measurements of these two crucial mosquito behavioural parameters should now be integrated into programmatically funded, longitudinal, national-scale entomological monitoring systems to inform selection of available technologies and investment in developing new ones. PMID:24739261

  17. A key component of the integrated control of vector-borne diseases such as malaria and

    E-print Network

    Read, Andrew

    for the control of locusts and grasshoppers to examine the potential for development of a biopesticide to infect mosquitoes in resting and breeding sites in residential settings. Biopesticides for locusts and grasshoppers chemical applications against locusts and grasshoppers in Africa, the international donor community sup

  18. Spray characterization of thermal fogging equipment typically used in vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The generation of insecticide laden fogs provides an effective method for controlling flying insects. One of the critical factors affecting the effectiveness of a thermal fogging application is the generation of droplets that will remain aloft in the fogging cloud and moves into the area where the ...

  19. Role of recombinant viral vectored vaccines for control of avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Both low pathogenic and highly pathogenic avian influenza viruses (AIV) can cause serious disease and disruptions of poultry markets around the world. Many different countries have used vaccination as a control tool for these diseases, but with varying affect. Vaccines when antigenically matched t...

  20. Sustained Reduction of the Dengue Vector Population Resulting from an Integrated Control Strategy Applied in Two Brazilian Cities

    PubMed Central

    Regis, Lêda N.; Acioli, Ridelane Veiga; Silveira, José Constantino; Melo-Santos, Maria Alice Varjal; Souza, Wayner Vieira; Ribeiro, Cândida M. Nogueira.; da Silva, Juliana C. Serafim.; Monteiro, Antonio Miguel Vieira; Oliveira, Cláudia M. F.; Barbosa, Rosângela M. R.; Braga, Cynthia; Rodrigues, Marco Aurélio Benedetti; Silva, Marilú Gomes N. M.; Ribeiro Jr., Paulo Justiniano; Bonat, Wagner Hugo; de Castro Medeiros, Liliam César; Carvalho, Marilia Sa; Furtado, André Freire

    2013-01-01

    Aedes aegypti has developed evolution-driven adaptations for surviving in the domestic human habitat. Several trap models have been designed considering these strategies and tested for monitoring this efficient vector of Dengue. Here, we report a real-scale evaluation of a system for monitoring and controlling mosquito populations based on egg sampling coupled with geographic information systems technology. The SMCP-Aedes, a system based on open technology and open data standards, was set up from March/2008 to October/2011 as a pilot trial in two sites of Pernambuco -Brazil: Ipojuca (10,000 residents) and Santa Cruz (83,000), in a joint effort of health authorities and staff, and a network of scientists providing scientific support. A widespread infestation by Aedes was found in both sites in 2008–2009, with 96.8%–100% trap positivity. Egg densities were markedly higher in SCC than in Ipojuca. A 90% decrease in egg density was recorded in SCC after two years of sustained control pressure imposed by suppression of >7,500,000 eggs and >3,200 adults, plus larval control by adding fishes to cisterns. In Ipojuca, 1.1 million mosquito eggs were suppressed and a 77% reduction in egg density was achieved. This study aimed at assessing the applicability of a system using GIS and spatial statistic analysis tools for quantitative assessment of mosquito populations. It also provided useful information on the requirements for reducing well-established mosquito populations. Results from two cities led us to conclude that the success in markedly reducing an Aedes population required the appropriate choice of control measures for sustained mass elimination guided by a user-friendly mosquito surveillance system. The system was able to support interventional decisions and to assess the program’s success. Additionally, it created a stimulating environment for health staff and residents, which had a positive impact on their commitment to the dengue control program. PMID:23844059

  1. Glycogen Synthase Kinase 3 Is a Potential Drug Target for African Trypanosomiasis Therapy?

    PubMed Central

    Ojo, Kayode K.; Gillespie, J. Robert; Riechers, Aaron J.; Napuli, Alberto J.; Verlinde, Christophe L. M. J.; Buckner, Frederick S.; Gelb, Michael H.; Domostoj, Mathias M.; Wells, Susan J.; Scheer, Alexander; Wells, Timothy N. C.; Van Voorhis, Wesley C.

    2008-01-01

    Development of a safe, effective, and inexpensive therapy for African trypanosomiasis is an urgent priority. In this study, we evaluated the validity of Trypanosoma brucei glycogen synthase kinase 3 (GSK-3) as a potential drug target. Interference with the RNA of either of two GSK-3 homologues in bloodstream-form T. brucei parasites led to growth arrest and altered parasite morphology, demonstrating their requirement for cell survival. Since the growth arrest after RNA interference appeared to be more profound for T. brucei GSK-3 “short” (Tb10.161.3140) than for T. brucei GSK-3 “long” (Tb927.7.2420), we focused on T. brucei GSK-3 short for further studies. T. brucei GSK-3 short with an N-terminal maltose-binding protein fusion was cloned, expressed, and purified in a functional form. The potency of a GSK-3-focused inhibitor library against the recombinant enzyme of T. brucei GSK-3 short, as well as bloodstream-form parasites, was evaluated with the aim of determining if compounds that inhibit enzyme activity could also block the parasites' growth and proliferation. Among the compounds active against the cell, there was an excellent correlation between activity inhibiting the T. brucei GSK-3 short enzyme and the inhibition of T. brucei growth. Thus, there is reasonable genetic and chemical validation of GSK-3 short as a drug target for T. brucei. Finally, selective inhibition may be required for therapy targeting the GSK-3 enzyme, and a molecular model of the T. brucei GSK-3 short enzyme suggests that compounds that selectively inhibit T. brucei GSK-3 short over the human GSK-3 enzymes can be found. PMID:18644955

  2. Glycogen synthase kinase 3 is a potential drug target for African trypanosomiasis therapy.

    PubMed

    Ojo, Kayode K; Gillespie, J Robert; Riechers, Aaron J; Napuli, Alberto J; Verlinde, Christophe L M J; Buckner, Frederick S; Gelb, Michael H; Domostoj, Mathias M; Wells, Susan J; Scheer, Alexander; Wells, Timothy N C; Van Voorhis, Wesley C

    2008-10-01

    Development of a safe, effective, and inexpensive therapy for African trypanosomiasis is an urgent priority. In this study, we evaluated the validity of Trypanosoma brucei glycogen synthase kinase 3 (GSK-3) as a potential drug target. Interference with the RNA of either of two GSK-3 homologues in bloodstream-form T. brucei parasites led to growth arrest and altered parasite morphology, demonstrating their requirement for cell survival. Since the growth arrest after RNA interference appeared to be more profound for T. brucei GSK-3 "short" (Tb10.161.3140) than for T. brucei GSK-3 "long" (Tb927.7.2420), we focused on T. brucei GSK-3 short for further studies. T. brucei GSK-3 short with an N-terminal maltose-binding protein fusion was cloned, expressed, and purified in a functional form. The potency of a GSK-3-focused inhibitor library against the recombinant enzyme of T. brucei GSK-3 short, as well as bloodstream-form parasites, was evaluated with the aim of determining if compounds that inhibit enzyme activity could also block the parasites' growth and proliferation. Among the compounds active against the cell, there was an excellent correlation between activity inhibiting the T. brucei GSK-3 short enzyme and the inhibition of T. brucei growth. Thus, there is reasonable genetic and chemical validation of GSK-3 short as a drug target for T. brucei. Finally, selective inhibition may be required for therapy targeting the GSK-3 enzyme, and a molecular model of the T. brucei GSK-3 short enzyme suggests that compounds that selectively inhibit T. brucei GSK-3 short over the human GSK-3 enzymes can be found. PMID:18644955

  3. Community-centred eco-bio-social approach to control dengue vectors: an intervention study from Myanmar

    PubMed Central

    Wai, Khin Thet; Htun, Pe Than; Oo, Tin; Myint, Hla; Lin, Zaw; Kroeger, Axel; Sommerfeld, Johannes; Petzold, Max

    2012-01-01

    Objectives To build up and analyse the feasibility, process, and effectiveness of a partnership-driven ecosystem management intervention in reducing dengue vector breeding and constructing sustainable partnerships among multiple stakeholders. Methods A community-based intervention study was conducted from May 2009 to January 2010 in Yangon city. Six high-risk and six low-risk clusters were randomized and allocated as intervention and routine service areas, respectively. For each cluster, 100 households were covered. Bi-monthly entomological evaluations (i.e. larval and pupal surveys) and household acceptability surveys at the end of 6-month intervention period were conducted, supplemented by qualitative evaluations. Intervention description The strategies included eco-friendly multi-stakeholder partner groups (Thingaha) and ward-based volunteers, informed decision-making of householders, followed by integrated vector management approach. Findings Pupae per person index (PPI) decreased at the last evaluation by 5.7% (0.35–0.33) in high-risk clusters. But in low-risk clusters, PPI remarkably decreased by 63.6% (0.33–0.12). In routine service area, PPI also decreased due to availability of Temephos after Cyclone Nargis. As for total number of pupae in all containers, when compared to evaluation 1, there was a reduction of 18.6% in evaluation 2 and 44.1% in evaluation 3 in intervention area. However, in routine service area, more reduction was observed. All intervention tools were found as acceptable, being feasible to implement by multi-stakeholder partner groups. Conclusions The efficacy of community-controlled partnership-driven interventions was found to be superior to the vertical approach in terms of sustainability and community empowerment. PMID:23318238

  4. Closed-Loop Simulation Study of the Ares I Upper Stage Thrust Vector Control Subsystem for Nominal and Failure Scenarios

    NASA Technical Reports Server (NTRS)

    Chicatelli, Amy; Fulton, Chris; Connolly, Joe; Hunker, Keith

    2010-01-01

    As a replacement to the current Shuttle, the Ares I rocket and Orion crew module are currently under development by the National Aeronautics and Space Administration (NASA). This new launch vehicle is segmented into major elements, one of which is the Upper Stage (US). The US is further broken down into subsystems, one of which is the Thrust Vector Control (TVC) subsystem which gimbals the US rocket nozzle. Nominal and off-nominal simulations for the US TVC subsystem are needed in order to support the development of software used for control systems and diagnostics. In addition, a clear and complete understanding of the effect of off-nominal conditions on the vehicle flight dynamics is desired. To achieve these goals, a simulation of the US TVC subsystem combined with the Ares I vehicle as developed. This closed-loop dynamic model was created using Matlab s Simulink and a modified version of a vehicle simulation, MAVERIC, which is currently used in the Ares I project and was developed by the Marshall Space Flight Center (MSFC). For this report, the effects on the flight trajectory of the Ares I vehicle are investigated after failures are injected into the US TVC subsystem. The comparisons of the off-nominal conditions observed in the US TVC subsystem with those of the Ares I vehicle flight dynamics are of particular interest.

  5. Impact of Education Campaign on Community-Based Vector Control in Hastening the Process of Elimination of Lymphatic Filariasis in Tamil Nadu, South India

    ERIC Educational Resources Information Center

    Nandha, B.; Krishnamoorthy, K.

    2012-01-01

    Globally mosquito-borne lymphatic filariasis (LF) is targeted for elimination by 2020. Towards this goal, the scope of community-based vector control as a supplementary strategy to mass drug administration (MDA) was assessed through an intensive education campaign and evaluated using pre- and post-educational surveys in an intervention and…

  6. Human antibody response to Aedes albopictus salivary proteins: a potential biomarker to evaluate the efficacy of vector control in an area of Chikungunya and Dengue Virus transmission.

    PubMed

    Doucoure, Souleymane; Mouchet, François; Cornelie, Sylvie; Drame, Papa Makhtar; D'Ortenzio, Eric; DeHecq, Jean Sébastien; Remoue, Franck

    2014-01-01

    Aedes borne viruses represent public health problems in southern countries and threat to emerge in the developed world. Their control is currently based on vector population control. Much effort is being devoted to develop new tools to control such arbovirus. Recent findings suggest that the evaluation of human antibody (Ab) response to arthropod salivary proteins is relevant to measuring the level of human exposure to mosquito bites. Using an immunoepidemiological approach, the present study aimed to assess the usefulness of the salivary biomarker for measuring the efficacy of Ae. albopictus control strategies in La Reunion urban area. The antisaliva Ab response of adult humans exposed to Ae. albopictus was evaluated before and after vector control measures. Our results showed a significant correlation between antisaliva Ab response and the level of exposure to vectors bites. The decrease of Ae. albopictus density has been detected by this biomarker two weeks after the implementation of control measures, suggesting its potential usefulness for evaluating control strategies in a short time period. The identification of species specific salivary proteins/peptides should improve the use of this biomarker. PMID:24822216

  7. Human Antibody Response to Aedes albopictus Salivary Proteins: A Potential Biomarker to Evaluate the Efficacy of Vector Control in an Area of Chikungunya and Dengue Virus Transmission

    PubMed Central

    Doucoure, Souleymane; Mouchet, François; Cornelie, Sylvie; Drame, Papa Makhtar; D'Ortenzio, Eric; DeHecq, Jean Sébastien; Remoue, Franck

    2014-01-01

    Aedes borne viruses represent public health problems in southern countries and threat to emerge in the developed world. Their control is currently based on vector population control. Much effort is being devoted to develop new tools to control such arbovirus. Recent findings suggest that the evaluation of human antibody (Ab) response to arthropod salivary proteins is relevant to measuring the level of human exposure to mosquito bites. Using an immunoepidemiological approach, the present study aimed to assess the usefulness of the salivary biomarker for measuring the efficacy of Ae. albopictus control strategies in La Reunion urban area. The antisaliva Ab response of adult humans exposed to Ae. albopictus was evaluatedbefore and after vector control measures. Our results showed a significant correlation between antisaliva Ab response and the level of exposure to vectors bites. The decrease of Ae. albopictus density has been detected by this biomarker two weeks after the implementation of control measures, suggesting its potential usefulness for evaluating control strategies in a short time period. The identification of species specific salivary proteins/peptides should improve the use of this biomarker. PMID:24822216

  8. Identification through DNA barcoding of Tabanidae (Diptera) vectors of surra disease in India.

    PubMed

    Banerjee, Dhriti; Kumar, Vikas; Maity, Aniruddha; Ghosh, Biswatosh; Tyagi, Kaomud; Singha, Devkant; Kundu, Shantanu; Laskar, Boni Amin; Naskar, Atanu; Rath, Shibananda

    2015-10-01

    Horse flies and deer flies are common names applied to members of the family Tabanidae (Diptera). Tabanid flies are pestiferous and of veterinary and medical importance, with about 244 species in India. They are major vectors of Trypanosoma evansi that causes trypanosomiasis (surra disease). Lack of stable morphological characters, and scarcity of taxonomic expertise, is major impediments for accurate species identification of these important pest and disease vectors. Molecular data, especially DNA barcode data, has been widely used in the identification of Diptera of economic importance. We evaluated the utility of DNA barcode data to discriminate the vectors of surra disease (trypanosomiasis) from India. We used barcode gap and reciprocal monophyly (neighbor-joining and Bayesian tree) criteria to analyze barcode data. A total of 46 specimens belonging to 7 species under four genera in two subfamilies were used for this study. DNA barcode data was not available previously for these species. Analysis revealed that all morphologically identifiable species can be discriminated using DNA barcoding data. Further, our study clearly demonstrated the presence of cryptic species in Chrysops dispar. Moreover, we revealed that closely related species without stable taxonomic distinguishing characters in the "Tabanus striatus species complex" can be discriminated using DNA barcode data. PMID:26126785

  9. Stable Expression of Lentiviral Antigens by Quality-Controlled Recombinant Mycobacterium bovis BCG Vectors.

    PubMed

    Hart, Bryan E; Asrican, Rose; Lim, So-Yon; Sixsmith, Jaimie D; Lukose, Regy; Souther, Sommer J R; Rayasam, Swati D G; Saelens, Joseph W; Chen, Ching-Ju; Seay, Sarah A; Berney-Meyer, Linda; Magtanong, Leslie; Vermeul, Kim; Pajanirassa, Priyadharshini; Jimenez, Amanda E; Ng, Tony W; Tobin, David M; Porcelli, Steven A; Larsen, Michelle H; Schmitz, Joern E; Haynes, Barton F; Jacobs, William R; Lee, Sunhee; Frothingham, Richard

    2015-07-01

    The well-established safety profile of the tuberculosis vaccine strain, Mycobacterium bovis bacille Calmette-Guérin (BCG), makes it an attractive vehicle for heterologous expression of antigens from clinically relevant pathogens. However, successful generation of recombinant BCG strains possessing consistent insert expression has encountered challenges in stability. Here, we describe a method for the development of large recombinant BCG accession lots which stably express the lentiviral antigens, human immunodeficiency virus (HIV) gp120 and simian immunodeficiency virus (SIV) Gag, using selectable leucine auxotrophic complementation. Successful establishment of vaccine stability stems from stringent quality control criteria which not only screen for highly stable complemented BCG ?leuCD transformants but also thoroughly characterize postproduction quality. These parameters include consistent production of correctly sized antigen, retention of sequence-pure plasmid DNA, freeze-thaw recovery, enumeration of CFU, and assessment of cellular aggregates. Importantly, these quality assurance procedures were indicative of overall vaccine stability, were predictive for successful antigen expression in subsequent passaging both in vitro and in vivo, and correlated with induction of immune responses in murine models. This study has yielded a quality-controlled BCG ?leuCD vaccine expressing HIV gp120 that retained stable full-length expression after 10(24)-fold amplification in vitro and following 60 days of growth in mice. A second vaccine lot expressed full-length SIV Gag for >10(68)-fold amplification in vitro and induced potent antigen-specific T cell populations in vaccinated mice. Production of large, well-defined recombinant BCG ?leuCD lots can allow confidence that vaccine materials for immunogenicity and protection studies are not negatively affected by instability or differences between freshly grown production batches. PMID:25924766

  10. Control of Pyrethroid-Resistant Chagas Disease Vectors with Entomopathogenic Fungi

    PubMed Central

    Pedrini, Nicolás; Mijailovsky, Sergio J.; Girotti, Juan R.; Stariolo, Raúl; Cardozo, Rubén M.; Gentile, Alberto; Juárez, M. Patricia

    2009-01-01

    Background Triatoma infestans-mediated transmission of Tripanosoma cruzi, the causative agent of Chagas disease, remains as a major health issue in southern South America. Key factors of T. infestans prevalence in specific areas of the geographic Gran Chaco region—which extends through northern Argentina, Bolivia, and Paraguay—are both recurrent reinfestations after insecticide spraying and emerging pyrethroid-resistance over the past ten years. Among alternative control tools, the pathogenicity of entomopathogenic fungi against triatomines is already known; furthermore, these fungi have the ability to fully degrade hydrocarbons from T. infestans cuticle and to utilize them as fuel and for incorporation into cellular components. Methodology and Findings Here we provide evidence of resistance-related cuticle differences; capillary gas chromatography coupled to mass spectrometry analyses revealed that pyrethroid-resistant bugs have significantly larger amounts of surface hydrocarbons, peaking 56.2±6.4% higher than susceptible specimens. Also, a thicker cuticle was detected by scanning electron microscopy (32.1±5.9 µm and 17.8±5.4 µm for pyrethroid-resistant and pyrethroid-susceptible, respectively). In laboratory bioassays, we showed that the virulence of the entomopathogenic fungi Beauveria bassiana against T. infestans was significantly enhanced after fungal adaptation to grow on a medium containing insect-like hydrocarbons as the carbon source, regardless of bug susceptibility to pyrethroids. We designed an attraction-infection trap based on manipulating T. infestans behavior in order to facilitate close contact with B. bassiana. Field assays performed in rural village houses infested with pyrethroid-resistant insects showed 52.4% bug mortality. Using available mathematical models, we predicted that further fungal applications could eventually halt infection transmission. Conclusions This low cost, low tech, ecologically friendly methodology could help in controlling the spread of pyrethroid-resistant bugs. PMID:19434231

  11. Vector Inflation

    E-print Network

    Golovnev, Alexey; Vanchurin, Vitaly

    2008-01-01

    We propose a scenario where inflation is driven by non-minimally coupled massive vector fields. In an isotropic homogeneous universe these fields behave in presicely the same way as a massive minimally coupled scalar field. Therefore our model is very similar to the model of chaotic inflation with scalar field. For vector fields the isotropy of expansion is achived either by considering a triplet of orthogonal vector fields or for the expense of $N$ randomly oriented vector fields. In this last case the substantial anisotropy of the expansion of order $1/\\sqrt{N}$ survives after inflation. The lightest vector fields might also force the late time acceleration of the Universe.

  12. Slowing the Spread of Grapevine Leafroll-Associated Viruses in Commercial Vineyards With Insecticide Control of the Vector, Pseudococcus maritimus (Hemiptera: Pseudococcidae)

    PubMed Central

    Fuchs, M. F.; Martinson, T.; Hesler, S.; Loeb, G. M.

    2015-01-01

    Vineyards were surveyed for grapevine leafroll-associated viruses and their insect vectors in New York State’s Finger Lakes region in 2006–2008. Grape mealybug, Pseudococcus maritimus (Erhorn) (Hemiptera: Pseudococcidae), European Fruit Lecanium, Parthenolecanium corni (Bouche), and Cottony Maple Scale, Pulvinaria acericola (Walsh and Riley) (Hemiptera: Coccidae) were identified as vector species in this region. An increase in the incidence of Grapevine leafroll-associated virus 1 (GLRaV-1) and GLRaV-3 was observed in 8 of the 20 vineyards surveyed, which implies transmission by these insect vectors. Two of the vineyards for which a temporal increase in disease incidence was documented were then used to evaluate the efficacy of foliar applications of horticultural oil and two classes of insecticides for control of P. maritimus and for slowing virus spread over 2 years of vine protection. Delayed dormant applications of horticultural oil contributed to control of early season crawlers; however, this was not the case for control of summer populations. Applications of acetamiprid and spirotetramat achieved control in summer populations; however, spirotetramat outperformed acetamiprid in percent reduction of treated compared with control vines and in a side-by-side trial. Vines treated with spirotetramat had a lower percentage of new vines testing positive for GLRaV-1 than control vines after 2 years, while no other spray program altered the increase in incidence of GLRaV-1 or -3. PMID:26223949

  13. Slowing the Spread of Grapevine Leafroll-Associated Viruses in Commercial Vineyards With Insecticide Control of the Vector, Pseudococcus maritimus (Hemiptera: Pseudococcidae).

    PubMed

    Wallingford, A K; Fuchs, M F; Martinson, T; Hesler, S; Loeb, G M

    2015-01-01

    Vineyards were surveyed for grapevine leafroll-associated viruses and their insect vectors in New York State's Finger Lakes region in 2006-2008. Grape mealybug, Pseudococcus maritimus (Erhorn) (Hemiptera: Pseudococcidae), European Fruit Lecanium, Parthenolecanium corni (Bouche), and Cottony Maple Scale, Pulvinaria acericola (Walsh and Riley) (Hemiptera: Coccidae) were identified as vector species in this region. An increase in the incidence of Grapevine leafroll-associated virus 1 (GLRaV-1) and GLRaV-3 was observed in 8 of the 20 vineyards surveyed, which implies transmission by these insect vectors. Two of the vineyards for which a temporal increase in disease incidence was documented were then used to evaluate the efficacy of foliar applications of horticultural oil and two classes of insecticides for control of P. maritimus and for slowing virus spread over 2 years of vine protection. Delayed dormant applications of horticultural oil contributed to control of early season crawlers; however, this was not the case for control of summer populations. Applications of acetamiprid and spirotetramat achieved control in summer populations; however, spirotetramat outperformed acetamiprid in percent reduction of treated compared with control vines and in a side-by-side trial. Vines treated with spirotetramat had a lower percentage of new vines testing positive for GLRaV-1 than control vines after 2 years, while no other spray program altered the increase in incidence of GLRaV-1 or -3. PMID:26223949

  14. Maggots as potential vector for pathogen transmission and consequences for infection control in waste management

    PubMed Central

    Daeschlein, Georg; Reese, Kevin; Napp, Matthias; Spitzmueller, Romy; Hinz, Peter; Juenger, Michael; Kramer, Axel

    2015-01-01

    Background and aims: Debridement therapy with sterile bred larvae in non-healing wounds is a widely accepted safe and efficient treatment modality. However, during application in the contaminated wound bed microbial contamination with potential microbial pathogen spread after escape from the wound or after unreliable disposal procedure may happen, particularly in the case of not using bio-bags. The aims of this work were first to investigate the release of ingested bacteria into the environment by maggots and second to examine the common practice of freezing the maggots after use and/or disposal in trash-bags. Potential methods for hygienic safe disposal of used maggots should be deduced. Methods: First, Maggots were contaminated with S. aureus by allowing them to crawl over an agar surface completely covered with bacterial growth over 24 h at 37°C. After external disinfection maggots were transferred onto sterile Columbia agar plates and shedding of S. aureus was visualized. Second, maggots were frozen at –20°C for 1, 2, 5, 10, 30, and 60 min. After exposure, the larvae were transferred onto Columbia blood agar with consecutive incubation at 37°C over 48 h. The larvae were analyzed visually for mobility and eating activities. The frozen bodies of dead larvae were examined for viable bacteria. Results: We could demonstrate that maggots release formerly ingested pathogens (S. aureus). Freezing at –20°C for at least 60 min was able to kill all maggots, however the contaminant bacteria inside could survive. Conclusion: Since freezing is apparently able to kill maggots but not to reliabely inactivate the ingested bacterial pathogens, we recommend the disposal of free-range larvae in screw cap vials after use to achieve full hygienic control. PMID:26029492

  15. Modified veranda-trap hut for improved evaluation of vector control interventions.

    PubMed

    Oxborough, R M; Kitau, J; Mosha, F W; Rowland, M W

    2015-12-01

    Experimental huts with veranda traps have been used in Tanzania since 1963 for the study of residual insecticides for use with insecticide-treated nets and indoor residual spraying. Mosquitoes are allowed unrestricted entry through the eaves to facilitate the collection of an estimable proportion of mosquitoes that attempt to exit through the eave gaps, which are left open on two sides of the hut. This study was designed to validate the use of eave baffles to funnel entry and to prevent mosquito escape, and to determine biting times of Anopheles arabiensis (Patton) (Diptera: Culicidae). Anopheles arabiensis and Culex quinquefasciatus (Say) (Diptera: Culicidae) were released into the room at 20.30 hours and collected the following morning from veranda traps, window traps and the room. Centers for Disease Control light traps hung overnight next to volunteers were emptied every 2 h to determine peak biting times. A total of 55% of An. arabiensis were trapped before 22.30 hours and the highest peak in 'biting' was recorded during 18.30-20.30 hours. Of the released An. arabiensis that exited into veranda traps, 7% were captured in veranda traps entered through baffles and 93% were captured in traps entered through unmodified eaves. When veranda screens were left open to allow for escape outdoors, recapture rates were 68% for huts with eave baffles and 39% for huts with unmodified eaves. The comparison of open eaves with baffled eaves validated the assumption that in huts of the traditional non-baffled design, 50% of mosquitoes escape through open eaves. Eave baffles succeeded in reducing the potential for mosquito exit and produced more precise estimates of effect. PMID:26194052

  16. Virtual globes and geospatial health: the potential of new tools in the management and control of vector-borne diseases.

    PubMed

    Stensgaard, Anna-Sofie; Saarnak, Christopher F L; Utzinger, Jürg; Vounatsou, Penelope; Simoonga, Christopher; Mushinge, Gabriel; Rahbek, Carsten; Møhlenberg, Flemming; Kristensen, Thomas K

    2009-05-01

    The rapidly growing field of three-dimensional software modeling of the Earth holds promise for applications in the geospatial health sciences. Easy-to-use, intuitive virtual globe technologies such as Google Earth enable scientists around the world to share their data and research results in a visually attractive and readily understandable fashion without the need for highly sophisticated geographical information systems (GIS) or much technical assistance. This paper discusses the utility of the rapid and simultaneous visualization of how the agents of parasitic diseases are distributed, as well as that of their vectors and/or intermediate hosts together with other spatially-explicit information. The resulting better understanding of the epidemiology of infectious diseases, and the multidimensional environment in which they occur, are highlighted. In particular, the value of Google Earth, and its web-based pendant Google Maps, are reviewed from a public health view point, combining results from literature searches and experiences gained thus far from a multidisciplinary project aimed at optimizing schistosomiasis control and transmission surveillance in sub-Saharan Africa. Although the basic analytical capabilities of virtual globe applications are limited, we conclude that they have considerable potential in the support and promotion of the geospatial health sciences as a userfriendly, straightforward GIS tool for the improvement of data collation, visualization and exploration. The potential of these systems for data sharing and broad dissemination of scientific research and results is emphasized. PMID:19440958

  17. Aristolochia indica green-synthesized silver nanoparticles: A sustainable control tool against the malaria vector Anopheles stephensi?

    PubMed

    Murugan, Kadarkarai; Labeeba, Mohammed Aamina; Panneerselvam, Chellasamy; Dinesh, Devakumar; Suresh, Udaiyan; Subramaniam, Jayapal; Madhiyazhagan, Pari; Hwang, Jiang-Shiou; Wang, Lan; Nicoletti, Marcello; Benelli, Giovanni

    2015-10-01

    Malaria is a life-threatening disease caused by parasites transmitted to people and animals through the bites of infected mosquitoes. We biosynthesized silver nanoparticles (AgNP) using Aristolochia indica extract as reducing and stabilizing agent. AgNP were characterized by UV-vis spectroscopy, FTIR, SEM, EDX and XRD. In laboratory, LC50 of A. indica extract against Anopheles stephensi ranged from 262.66 (larvae I) to 565.02 ppm (pupae). LC50 of AgNP against A. stephensi ranged from 3.94 (larvae I) to 15.65 ppm (pupae). In the field, the application of A. indica extract and AgNP (10 × LC50) leads to 100% larval reduction after 72 h. In laboratory, 24-h predation efficiency of Diplonychus indicus against A. stephensi larvae was 33% (larvae II) and 57% (larvae III). In AgNP-contaminated environment (1 ppm), it was 45.5% (larvae II) and 71.75% (larvae III). Overall, A. indica-synthesized AgNP may be considered as newer and safer control tools against Anopheles vectors. PMID:26412532

  18. Large fluctuations in the effective population size of the malaria mosquito Anopheles gambiae s.s. during vector control cycle

    PubMed Central

    Hodges, Theresa K; Athrey, Giridhar; Deitz, Kevin C; Overgaard, Hans J; Matias, Abrahan; Caccone, Adalgisa; Slotman, Michel A

    2013-01-01

    On Bioko Island, Equatorial Guinea, indoor residual spraying (IRS) has been part of the Bioko Island Malaria Control Project since early 2004. Despite success in reducing childhood infections, areas of high transmission remain on the island. We therefore examined fluctuations in the effective population size (Ne) of the malaria vector Anopheles gambiae in an area of persistent high transmission over two spray rounds. We analyzed data for 13 microsatellite loci from 791 An. gambiae specimens collected at six time points in 2009 and 2010 and reconstructed the demographic history of the population during this period using approximate Bayesian computation (ABC). Our analysis shows that IRS rounds have a large impact on Ne, reducing it by 65%–92% from prespray round Ne. More importantly, our analysis shows that after 3–5 months, the An. gambiae population rebounded by 2818% compared shortly following the spray round. Our study underscores the importance of adequate spray round frequency to provide continuous suppression of mosquito populations and that increased spray round frequency should substantially improve the efficacy of IRS campaigns. It also demonstrates the ability of ABC to reconstruct a detailed demographic history across only a few tens of generations in a large population. PMID:24478799

  19. 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 ?l/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 ?l/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. PMID:26063530

  20. Community based interventions for the prevention and control of Non-Helmintic NTD

    PubMed Central

    2014-01-01

    In this paper, we aim to systematically analyze the effectiveness of community based interventions (CBI) for the prevention and control of non-helminthic diseases including dengue, trypanosomiasis, chagas, leishmaniasis, buruli ulcer, leprosy and trachoma. We systematically reviewed literature published up to May 2013 and included 62 studies in this review. Findings from our review suggest that CBI including insecticide spraying; insecticide treated bednets and curtains; community education and cleanliness campaigns; chemoprophylaxis through mass drug administration; and treatment have the potential to reduce the incidence and burden of non-helminthic diseases. Lack of data limited the subgroup analysis for integrated and non-integrated delivery strategies however, qualitative synthesis suggest that integrated delivery is more effective when compared to vertical interventions; however, such integration was possible only because of the existing vertical vector control programs. Community delivered interventions have the potential to achieve wider coverage and sustained community acceptance. Eradicating these diseases will require a multipronged approach including drug administration, health education, vector control and clean water and sanitation facilities. This would require high level governmental commitment along with strong partnerships among major stakeholders. PMID:25114794

  1. A lentiviral vector with expression controlled by E2F-1: A potential tool for the study and treatment of proliferative diseases

    SciTech Connect

    Strauss, Bryan E.; Vieira de Carvalho, Anna Carolina; Bajgelman, Marcio C.

    2006-10-06

    We have constructed a lentiviral vector with expression limited to cells presenting active E2F-1 protein, a potential advantage for gene therapy of proliferative diseases. For the FE2FLW vector, the promoter region of the human E2F-1 gene was utilized to drive expression of luciferase cDNA, included as a reporter of viral expression. Primary, immortalized, and transformed cells were transduced with the FE2FLW vector and cell cycle alterations were induced with serum starvation/replacement, contact inhibition or drug treatment, revealing cell cycle-dependent changes in reporter activity. Forced E2F-1 expression, but not E2F-2 or E2F-3, increased reporter activity, indicating a major role for this factor in controlling expression from the FE2FLW virus. We show the utility of this vector as a reporter of E2F-1 and proliferation-dependent cellular alterations upon cytotoxic/cytostatic treatment, such as the introduction of tumor suppressor genes. We propose that the FE2FLW vector may be a starting point for the development of gene therapy strategies for proliferative diseases, such as cancer or restinosis.

  2. BIONOMICS AND ECOLOGY OF ANOPHELES LITORALIS ON BONGAO ISLAND, TAWI-TAWI PROVINCE, PHILIPPINES: IMPLICATIONS FOR VECTOR CONTROL.

    PubMed

    Salazar, Ferdinand V; Torno, Majhalia M; Galang, Cristina; Baquilod, Mario; Bangs, Michael J

    2015-05-01

    Entomological surveys were conducted to identify Anopheles malaria vector species, their feeding and resting behaviors, and characterization of larval habitats on Bongao Island, Tawi-tawi Province, in July and November, 2007. Survey parameters included all-evening human-landing collections (HLC), evening buffalo-baited trap (BBT) collections, daytime indoor and outdoor adult resting collections, adult female age-grading, identification of natural Plasmodium infections in mosquitoes, larval habitat identification and physical/biological characterization, and adult insecticide susceptibility assays. Both surveys revealed the predominant and putative malaria vector species on Bongao Island is Anopheles litoralis. Anophelesflavirostris was collected on only one occasion. The HLC during the July survey produced approximately 4 mosquitoes/human/night (mhn). The November survey yielded 1.27 mhn due, in part, to inclement weather conditions during time of sampling. Anopheles litoralis host seeking behavior occurred throughout the evening (06:00 PM - 06:00 AM) with peak biting between 10:00 PM and 04:00 AM. This species exhibited stronger zoophilic behavior based on comparison of HLC and BBT data. HLC showed a slightly greater exophagic (outdoor) behavior (1.4:1 ratio). During the July collection, an older adult population was present (75% parous) compared to the lower numbers of An. litoralis dissected in November (25% parous). Albeit a small sample size (n=19), 10.5% of An. litoralis dissected contained midgut oocysts of Plasmodium. Daytime adult resting harborages included biotic and abiotic sites in and around partially shaded, brackish water habitats where immature stages were common. Anopheles litoralis was found susceptible to pirimiphos-methyl and four different synthetic pyrethroids. This survey provides further epidemiological evidence of the importance of An. litoralis in malaria transmission on Bongao Island, and presumably throughout much of the Sulu Archipelago in the southern Philippines. Published observations of this species remain very limited and further investigations on the bionomics and epidemiological importance of this species are needed. Both ecological and human factors in malaria transmission are presented with implications for improved control of An. litoralis and prevention of infection. PMID:26521514

  3. Effectiveness and feasibility of long-lasting insecticide-treated curtains and water container covers for dengue vector control in Colombia: a cluster randomised trial

    PubMed Central

    Quintero, Juliana; García-Betancourt, Tatiana; Cortés, Sebastian; García, Diana; Alcalá, Lucas; González-Uribe, Catalina; Brochero, Helena; Carrasquilla, Gabriel

    2015-01-01

    Background Long-lasting insecticide-treated net (LLIN) window and door curtains alone or in combination with LLIN water container covers were analysed regarding effectiveness in reducing dengue vector density, and feasibility of the intervention. Methods A cluster randomised trial was conducted in an urban area of Colombia comparing 10 randomly selected control and 10 intervention clusters. In control clusters, routine vector control activities were performed. The intervention delivered first, LLIN curtains (from July to August 2013) and secondly, water container covers (from October to March 2014). Cross-sectional entomological surveys were carried out at baseline (February 2013 to June 2013), 9 weeks after the first intervention (August to October 2013), and 4–6 weeks after the second intervention (March to April 2014). Results Curtains were installed in 922 households and water container covers in 303 households. The Breteau index (BI) fell from 14 to 6 in the intervention group and from 8 to 5 in the control group. The additional intervention with LLIN covers for water containers showed a significant reduction in pupae per person index (PPI) (p=0.01). In the intervention group, the PPI index showed a clear decline of 71% compared with 25% in the control group. Costs were high but options for cost savings were identified. Conclusions Short term impact evaluation indicates that the intervention package can reduce dengue vector density but sustained effect will depend on multiple factors. PMID:25604762

  4. Alternative Treatments for Indoor Residual Spraying for Malaria Control in a Village with Pyrethroid- and DDT-Resistant Vectors in The Gambia

    PubMed Central

    Tangena, Julie-Anne A.; Adiamoh, Majidah; D’Alessandro, Umberto; Jarju, Lamin; Jawara, Musa; Jeffries, David; Malik, Naiela; Nwakanma, Davis; Kaur, Harparkash; Takken, Willem; Lindsay, Steve W.; Pinder, Margaret

    2013-01-01

    Background Malaria vector control is threatened by resistance to pyrethroids, the only class of insecticides used for treating bed nets. The second major vector control method is indoor residual spraying with pyrethroids or the organochloride DDT. However, resistance to pyrethroids frequently confers resistance to DDT. Therefore, alternative insecticides are urgently needed. Methodology/Principal Findings Insecticide resistance and the efficacy of indoor residual spraying with different insecticides was determined in a Gambian village. Resistance of local vectors to pyrethroids and DDT was high (31% and 46% mortality, respectively) while resistance to bendiocarb and pirimiphos methyl was low (88% and 100% mortality, respectively). The vectors were predominantly Anopheles gambiae s.s. with 94% of them having the putative resistant genotype kdr 1014F. Four groups of eight residential compounds were each sprayed with either (1) bendiocarb, a carbamate, (2) DDT, an organochlorine, (3) microencapsulated pirimiphos methyl, an organophosphate, or (4) left unsprayed. All insecticides tested showed high residual activity up to five months after application. Mosquito house entry, estimated by light traps, was similar in all houses with metal roofs, but was significantly less in IRS houses with thatched roofs (p=0.02). Residents participating in focus group discussions indicated that IRS was considered a necessary nuisance and also may decrease the use of long-lasting insecticidal nets. Conclusion/Significance Bendiocarb and microencapsulated pirimiphos methyl are viable alternatives for indoor residual spraying where resistance to pyrethroids and DDT is high and may assist in the management of pyrethroid resistance. PMID:24058551

  5. Future challenges for parasitology: vector control and 'One health' in Europe: the veterinary medicinal view on CVBDs such as tick borreliosis, rickettsiosis and canine leishmaniosis.

    PubMed

    Mencke, Norbert

    2013-08-01

    The medical as well as the veterinary importance of parasitic arthropods or ectoparasites in general terms, is characterized by the primary or secondary impact on the health of humans and companion animals alike. The parasitic arthropods addressed here are those ectoparasites belong to the class of insects, such as fleas and sand flies, or the subclass of acarids, such as ticks. These parasitic arthropods interact intensively with their hosts by blood feeding. Fleas, sand flies and ticks hold the vector capacity to transmit pathogens such as virus, bacteria or protozoa to cats, dogs and humans. The diseases caused by these pathogens are summarized under the terms canine vector-borne diseases (CVBD), feline vector-borne diseases (FVBD) or metazoonoses. In small animal practice, it is important to understand that the transmitted pathogen may either lead to a disease with clinical signs, or more often to asymptomatic, clinically healthy, or silent infections. Blocking of the vector-host interactions, the blood feeding and subsequently the transmission of pathogens during blood feeding is a key element of CVBD control. The focus of this review is on the current knowledge of the epidemiology of parasitic vectors and three important CVBDs they transmit; rickettsiosis, tick borreliosis and canine leishmaniosis from a European perspective, and how veterinary medicine may contribute to the challenges of CVBDs and their control. Prevention of CVBDs is fundamentally based on ectoparasite control. Ectoparasite management in cats and dogs is important not only for the health and well-being of the individual companion animal but for public health in general and is therefore a perfect example of the 'One health' approach. PMID:23680539

  6. Biological Control of the Chagas Disease Vector Triatoma infestans with the Entomopathogenic Fungus Beauveria bassiana Combined with an Aggregation Cue: Field, Laboratory and Mathematical Modeling Assessment

    PubMed Central

    Forlani, Lucas; Pedrini, Nicolás; Girotti, Juan R.; Mijailovsky, Sergio J.; Cardozo, Rubén M.; Gentile, Alberto G.; Hernández-Suárez, Carlos M.; Rabinovich, Jorge E.; Juárez, M. Patricia

    2015-01-01

    Background Current Chagas disease vector control strategies, based on chemical insecticide spraying, are growingly threatened by the emergence of pyrethroid-resistant Triatoma infestans populations in the Gran Chaco region of South America. Methodology and findings We have already shown that the entomopathogenic fungus Beauveria bassiana has the ability to breach the insect cuticle and is effective both against pyrethroid-susceptible and pyrethroid-resistant T. infestans, in laboratory as well as field assays. It is also known that T. infestans cuticle lipids play a major role as contact aggregation pheromones. We estimated the effectiveness of pheromone-based infection boxes containing B. bassiana spores to kill indoor bugs, and its effect on the vector population dynamics. Laboratory assays were performed to estimate the effect of fungal infection on female reproductive parameters. The effect of insect exuviae as an aggregation signal in the performance of the infection boxes was estimated both in the laboratory and in the field. We developed a stage-specific matrix model of T. infestans to describe the fungal infection effects on insect population dynamics, and to analyze the performance of the biopesticide device in vector biological control. Conclusions The pheromone-containing infective box is a promising new tool against indoor populations of this Chagas disease vector, with the number of boxes per house being the main driver of the reduction of the total domestic bug population. This ecologically safe approach is the first proven alternative to chemical insecticides in the control of T. infestans. The advantageous reduction in vector population by delayed-action fungal biopesticides in a contained environment is here shown supported by mathematical modeling. PMID:25969989

  7. An exploratory GIS-based method to identify and characterise landscapes with an elevated epidemiological risk of Rhodesian human African trypanosomiasis

    PubMed Central

    2012-01-01

    Background Specific land cover types and activities have been correlated with Trypanosoma brucei rhodesiense distributions, indicating the importance of landscape for epidemiological risk. However, methods proposed to identify specific areas with elevated epidemiological risk (i.e. where transmission is more likely to occur) tend to be costly and time consuming. This paper proposes an exploratory spatial analysis using geo-referenced human African trypanosomiasis (HAT) cases and matched controls from Serere hospital, Uganda (December 1998 to November 2002) to identify areas with an elevated epidemiological risk of HAT. Methods Buffers 3 km from each case and control were used to represent areas in which village inhabitants would carry out their daily activities. It was hypothesised that the selection of areas where several case village buffers overlapped would enable the identification of locations with increased risk of HAT transmission, as these areas were more likely to be frequented by HAT cases in several surrounding villages. The landscape within these overlap areas should more closely relate to the environment in which transmission occurs as opposed to using the full buffer areas. The analysis was carried out for each of four annual periods, for both cases and controls, using a series of threshold values (number of overlapping buffers), including a threshold of one, which represented the benchmark (e.g. use of the full buffer area as opposed to the overlap areas). Results A greater proportion of the overlap areas for cases consisted of seasonally flooding grassland and lake fringe swamp, than the control overlap areas, correlating well with the preferred habitat of the predominant tsetse species within the study area (Glossina fuscipes fuscipes). The use of overlap areas also resulted in a greater difference between case and control landscapes, when compared with the benchmark (using the full buffer area). Conclusions These results indicate that the overlap analysis has enabled the selection of areas more likely to represent epidemiological risk zones than similar analyses using full buffer areas. The identification of potential epidemiological risk zones using this method requires fewer data than other proposed methods and further development may provide vital information for the targeting of control measures. PMID:23171150

  8. Control vectors for splines

    E-print Network

    Kosinka, Ji?i; Sabin, Malcolm A.; Dodgson, Neil A.

    2014-09-03

    . Introduction Splines have their roots in the lofting technique used in the shipbuilding and aircraft industries throughout the first half of the 20th century. The first mathematical reference to the notion of splines is accredited to the work of Schoenberg [1... discontinuous function) without having to remesh. Recently, due to the popularity of Isogeometric Analysis (IgA for short; see [15]), such modifications are ever more important. These modifications, however, break the partition of unity property and cannot...

  9. Potential of contact insecticides to control Xyleborus glabratus (Coleoptera: Curculionidae), a vector of laurel wilt disease in avocados.

    PubMed

    Carrillo, Daniel; Crane, Jonathan H; Peña, Jorge E

    2013-12-01

    Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae) is an invasive ambrosia beetle that vectors laurel wilt, a new disease that threatens avocado and other species in the Lauraceae Family. The lethal concentrations (LC50 & 90) of nine commercial insecticides to X. glabratus were determined by using a bolt-dip bioassay. Different formulations of bifenthrin, permethrin, fenpropathrin, z-cypermethrin + bifenthrin, 1-cyhalothrin + thiamethoxam, malathion, chlorpyrifos, carbaryl, and methomyl were tested. Four concentrations of each insecticide were tested (0.5, 0.1, 0.03, and 0.01 of the label rate) and with water as a control. Beetles were exposed to treated bolts and mortality registered 48 h later. After 2 wk, bolts were destructively sampled to determine the number of beetles that constructed galleries and were alive inside the wood. Probit analysis was used to determine the LC50 & 90. Six pesticides were applied directly to the trunk and limbs of avocado trees in a commercial grove. Limbs of treated trees were cut weekly after the application and exposed to X. glabratus to determine the number of beetles boring into the logs. The toxicity of pesticides to X. glabratus was greatly reduced 2 wk after application. Among the tested pesticides, malathion and z-cypermethrin + bifenthrin provided the best suppression of X. glabratus. Among the insecticides registered for use in avocado, fenpropathrin and malathion were the most effective in protecting trees from attack by X. glabratus. Other pesticides that are currently not registered for use in avocados could be useful for managing this ambrosia beetle. PMID:24498726

  10. Kinase scaffold repurposing for neglected disease drug discovery: Discovery of an efficacious, lapatanib-derived lead compound for trypanosomiasis

    PubMed Central

    Patel, Gautam; Karver, Caitlin E.; Behera, Ranjan; Guyett, Paul; Sullenberger, Catherine; Edwards, Peter; Roncal, Norma E.; Mensa-Wilmot, Kojo; Pollastri, Michael P.

    2013-01-01

    Human African trypanosomiasis (HAT) is a neglected tropical disease caused by the protozoan parasite Trypanosoma brucei. Since drugs in use against HAT are toxic and require intravenous dosing, new drugs are needed. Initiating lead discovery campaigns by using chemical scaffolds from drugs approved for other indications can speed up drug discovery for neglected diseases. We demonstrated recently that the 4-anilinoquinazolines lapatinib (GW572016, 1) and canertinib (CI-1033) kill T. brucei with low micromolar EC50 values. We now report promising activity of analogs of 1, which provided an excellent starting point for optimization of the chemotype. We report our compound optimization that has led to synthesis of several potent 4-anilinoquinazolines, including NEU621, 23a, a highly potent, orally bioavailable inhibitor of trypanosome replication. At the cellular level, 23a blocks duplication of the kinetoplast and arrests cytokinesis, making it a new tool for studying regulation of the trypanosome cell cycle. PMID:23597080

  11. Preliminary performance of a vertical-attitude takeoff and landing, supersonic cruise aircraft concept having thrust vectoring integrated into the flight control system

    NASA Technical Reports Server (NTRS)

    Robins, A. W.; Beissner, F. L., Jr.; Domack, C. S.; Swanson, E. E.

    1985-01-01

    A performance study was made of a vertical attitude takeoff and landing (VATOL), supersonic cruise aircraft concept having thrust vectoring integrated into the flight control system. Those characteristics considered were aerodynamics, weight, balance, and performance. Preliminary results indicate that high levels of supersonic aerodynamic performance can be achieved. Further, with the assumption of an advanced (1985 technology readiness) low bypass ratio turbofan engine and advanced structures, excellent mission performance capability is indicated.

  12. Vector Inflation

    E-print Network

    Alexey Golovnev; Viatcheslav Mukhanov; Vitaly Vanchurin

    2008-06-10

    We propose a scenario where inflation is driven by non-minimally coupled massive vector fields. In an isotropic homogeneous universe these fields behave in presicely the same way as a massive minimally coupled scalar field. Therefore our model is very similar to the model of chaotic inflation with scalar field. For vector fields the isotropy of expansion is achived either by considering a triplet of orthogonal vector fields or for the expense of $N$ randomly oriented vector fields. In the last case the substantial anisotropy of the expansion of order $1/\\sqrt{N}$ survives until the end of inflation. The lightest vector fields might also force the late time acceleration of the Universe.

  13. Neglected Diseases in the News: A Content Analysis of Recent International Media Coverage Focussing on Leishmaniasis and Trypanosomiasis

    PubMed Central

    Balasegaram, Mangai; Balasegaram, Sooria; Malvy, Denis; Millet, Pascal

    2008-01-01

    Background Although the pharmaceutical industry's “neglect” of neglected tropical diseases (NTDs) has been investigated, no study evaluating media coverage of NTDs has been published. Poor media coverage exacerbates the neglect. This study aimed to investigate, describe, and analyse international media coverage of “neglected diseases” in general and three specific NTDs—African trypanosomiasis, leishmaniasis, and Chagas disease—from 1 January 2003 to 1 June 2007. Methods Archives of 11 leading international, English-language media were searched. A content analysis was done, coding for media organisation, date, author, type of report, slant, themes, and “frames”. Semi-structured interviews with journalists and key informants were conducted for further insight. Principal Findings Only 113 articles in a 53-month time period met the inclusion criteria, with no strong trends or increases in coverage. Overall, the BBC had the highest coverage with 20 results, followed by the Financial Times and Agence France Presse. CNN had the least coverage with one result. The term “neglected diseases” had good media currency and “sleeping sickness” was far more widely used than trypanosomiasis. The disease most covered was leishmaniasis and the least covered was Chagas. Academic researchers were most commonly quoted as a main source, while the World Health Organization (WHO) and pharmaceutical industry were the least quoted. Journalists generally agreed NTDs had not been adequately covered, but said a lack of real news development and the need to cater to domestic audiences were major obstacles for NTD reporting. All journalists said health agencies, particularly WHO, were not communicating adequately about the burden of NTDs. Conclusions Public health agencies need to raise priority for NTD advocacy. Innovative strategies, such as reporting grants or creating a network of voices, may be needed. PMID:18478048

  14. Long-lasting insecticide-treated house screens and targeted treatment of productive breeding-sites for dengue vector control in Acapulco, Mexico

    PubMed Central

    Che-Mendoza, Azael; Guillermo-May, Guillermo; Herrera-Bojórquez, Josué; Barrera-Pérez, Mario; Dzul-Manzanilla, Felipe; Gutierrez-Castro, Cipriano; Arredondo-Jiménez, Juan I.; Sánchez-Tejeda, Gustavo; Vazquez-Prokopec, Gonzalo; Ranson, Hilary; Lenhart, Audrey; Sommerfeld, Johannes; McCall, Philip J.; Kroeger, Axel; Manrique-Saide, Pablo

    2015-01-01

    Background Long-lasting insecticidal net screens (LLIS) fitted to domestic windows and doors in combination with targeted treatment (TT) of the most productive Aedes aegypti breeding sites were evaluated for their impact on dengue vector indices in a cluster-randomised trial in Mexico between 2011 and 2013. Methods Sequentially over 2 years, LLIS and TT were deployed in 10 treatment clusters (100 houses/cluster) and followed up over 24 months. Cross-sectional surveys quantified infestations of adult mosquitoes, immature stages at baseline (pre-intervention) and in four post-intervention samples at 6-monthly intervals. Identical surveys were carried out in 10 control clusters that received no treatment. Results LLIS clusters had significantly lower infestations compared to control clusters at 5 and 12 months after installation, as measured by adult (male and female) and pupal-based vector indices. After addition of TT to the intervention houses in intervention clusters, indices remained significantly lower in the treated clusters until 18 (immature and adult stage indices) and 24 months (adult indices only) post-intervention. Conclusions These safe, simple affordable vector control tools were well-accepted by study participants and are potentially suitable in many regions at risk from dengue worldwide. PMID:25604761

  15. Global Change and Human Vulnerability to Vector-Borne Diseases

    PubMed Central

    Sutherst, Robert W.

    2004-01-01

    Global change includes climate change and climate variability, land use, water storage and irrigation, human population growth and urbanization, trade and travel, and chemical pollution. Impacts on vector-borne diseases, including malaria, dengue fever, infections by other arboviruses, schistosomiasis, trypanosomiasis, onchocerciasis, and leishmaniasis are reviewed. While climate change is global in nature and poses unknown future risks to humans and natural ecosystems, other local changes are occurring more rapidly on a global scale and are having significant effects on vector-borne diseases. History is invaluable as a pointer to future risks, but direct extrapolation is no longer possible because the climate is changing. Researchers are therefore embracing computer simulation models and global change scenarios to explore the risks. Credible ranking of the extent to which different vector-borne diseases will be affected awaits a rigorous analysis. Adaptation to the changes is threatened by the ongoing loss of drugs and pesticides due to the selection of resistant strains of pathogens and vectors. The vulnerability of communities to the changes in impacts depends on their adaptive capacity, which requires both appropriate technology and responsive public health systems. The availability of resources in turn depends on social stability, economic wealth, and priority allocation of resources to public health. PMID:14726459

  16. Cloning vector

    DOEpatents

    Guilfoyle, Richard A. (Madison, WI); Smith, Lloyd M. (Madison, WI)

    1994-01-01

    A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site.

  17. Cloning vector

    DOEpatents

    Guilfoyle, R.A.; Smith, L.M.

    1994-12-27

    A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site. 2 figures.

  18. Control of human filarial vector, Culex quinquefasciatus Say 1823 (Diptera: Culicidae) through bioactive fraction of Cayratia trifolia leaf

    PubMed Central

    Chakraborty, Sumanta; Singha, Someshwar; Bhattacharya, Kuntal; Chandra, Goutam

    2013-01-01

    Objective To investigate the mosquito larvicidal activity of Cayratia trifolia (L.) Domin (Vitaceae: Vitales) (C. trifolia) which is distributed in many parts of India with medicinal properties as vector control is facing threat due to the emergence of resistance to synthetic insecticides. Methods Young and mature leaves of C. trifolia were investigated for larvicidal activity against 3rd instars larvae of Culex quinquefasciatus in different seasons throughout the year. The active fractions were extracted using six different solvents in a non-polar to polar fashion viz petroleum-ether, benzene, chloroform: methanol (1:1 v/v), acetone, absolute alcohol and distilled water. Dose dependent mortality was recorded against each solvent extract. Determination of LD50 and LD90 were executed through log-probit analysis using the most bioactive fraction. The fluctuations in mortality were statistically co-related through ANOVA analyses concerning different seasons and types of leaves as random variables. Justification of larvicidal activity was established through student's t-test. Costing effects were evaluated on the non-target water fauna under laboratory conditions. Thin layer chromatographic techniques were performed for phytochemical analysis and categorization of chemical personality of the active fractions using the most effective solvent extract following standard methods. Results Significant variations in mortality rate were noted with respect to the type of leaves (mature and senescence), concentration of leaf extract and between seasons. The water extract among all the solvent extracts was found to induce cent percent mortality at 50 mg/L in test mosquito species within 24 h with a LD50 and LD90 value of 10.70 mg/L and 27.64 mg/L respectively. No significant mortality was recorded in non-target water population. Chromatographic analyses of the water extract revealed the presence of steroids, triterpene glycosides, essential oil, phenolics and diterpenes as secondary phytochemicals. Conclusions Water extract of C. trifolia leaf promised as a cost effective and potent larvicidal agent against Culex quinquefasciatus. PMID:24093790

  19. Vector-control personnel’s knowledge, perceptions and practices towards insecticides used for indoor residual spraying in Limpopo Province, South Africa

    PubMed Central

    2013-01-01

    Background Contradictory arguments regarding the benefits and harm of insecticides, especially DDT, have caused concerns in different societal circles, threatening to undermine the achievements of the indoor residual spraying (IRS) programme in South Africa. These concerns were exacerbated by the screening of a documentary on South African Broadcasting Corporation (SABC) Television with anti-DDT sentiments. Consequently, Limpopo Malaria Control Programme (LMCP) Management advocated for an investigation to determine the potential effect of such campaigns on vector-control personnel’s knowledge and perceived effects of insecticides on human health, with a view to improving the educational materials designed for use in training vector-control personnel. Methods The study was a cross-sectional descriptive survey using a structured field-piloted questionnaire, administered to 233 randomly selected vector-control personnel. Ethical clearance was granted by the University of KwaZulu-Natal. Approval for the study was granted by the Department of Health, Limpopo. Participation in the study was voluntary and all respondents signed informed consent. Descriptive statistics were used to analyse the collected data. Results Most respondents (96.6%) had a positive perception of IRS as a method to control malaria. Despite their positive perception, 93.6% viewed IRS insecticides to be potentially harmful to the users. DDT was perceived to cause long-term reproductive and respiratory effects, whereas alpha-cypermethrin and deltamethrin were largely associated with skin irritation/itchiness and skin burn. Study participants were more worried about DDT’s potential effects on their reproductive system, including poor sexual performance, decline in libido, miscarriage and bearing children with genetic defects. However, none reported personal experience of bearing a child with genetic defects or miscarriage. Most anti-insecticide messages, especially relating to DDT, emanated from sources external to the LMCP, mainly through radio (62%) and television (33.9%) and about 70% believed such messages. While most respondents preferred to work with a moderately itchy deltamethrin, DDT was admittedly the most effective insecticide. Conclusion Vector-control personnel faced health and ethical dilemmas, in that, while they perceived insecticides used for IRS in Limpopo to be potentially harmful to the health of users, as purported through media, they also viewed IRS using insecticides to be effective in controlling malaria. PMID:23618516

  20. Equivalent Vectors

    ERIC Educational Resources Information Center

    Levine, Robert

    2004-01-01

    The cross-product is a mathematical operation that is performed between two 3-dimensional vectors. The result is a vector that is orthogonal or perpendicular to both of them. Learning about this for the first time while taking Calculus-III, the class was taught that if AxB = AxC, it does not necessarily follow that B = C. This seemed baffling. The…

  1. Vector quantization

    NASA Technical Reports Server (NTRS)

    Gray, Robert M.

    1989-01-01

    During the past ten years Vector Quantization (VQ) has developed from a theoretical possibility promised by Shannon's source coding theorems into a powerful and competitive technique for speech and image coding and compression at medium to low bit rates. In this survey, the basic ideas behind the design of vector quantizers are sketched and some comments made on the state-of-the-art and current research efforts.

  2. Gene expression in Asian citrus psyllid adults feeding from Florida citrus: Application to biology and vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used a genomics approach to identify some of the genetic basis of D. citri biology, identifying in particular genes associated with feeding, reproduction, pathology, and insecticide resistance. The Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae), is a highly competent vector ...

  3. Knowledge, attitudes and preventive behaviors related to dengue vector breeding control measures among adults in communities of Vientiane, capital of the Lao PDR.

    PubMed

    Sayavong, Chanthalay; Chompikul, Jiraporn; Wongsawass, Somsak; Rattanapan, Cheerwit

    2015-01-01

    This research aimed to determine the knowledge, attitudes and preventive behaviors (KAP) of adults in relation to dengue vector control measures in the communities of Vientiane, the capital of the Lao PDR. A total of 207 respondents were actively participating in this cross-sectional descriptive study in 2011. Representatives of households were interviewed face-to-face by six trained interviewers using a structured questionnaire. KAP reliabilities of 0.89, 0.91 and 0.95 were reported in the pilot sample of 30 cases. The associations between each independent variable and prevention behavior were tested with chi-square tests. Multiple logistic regression was used to determine the factors that were significantly associated with preventive behavior while controlling for the other variables. The results revealed that 51.69% of the respondents had a high level of knowledge. More than 94% of the respondents knew that dengue fever is a dangerous communicable disease and that dengue fever is transmitted from person to person via mosquitoes. More than half (56.52%) of the participants had positive attitudes toward vector control measures, and 52.17% exhibited a high level of preventive behavior in terms of dengue vector control measures. Preventive behaviors were significantly associated with information provided from sources that included health personnel (p = 0.038) and heads of villages (p=0.031) and with knowledge levels (p < 0.001). This study suggests that proactive health education through appropriated mass media and community clean-up campaigns should strengthen and encourage community participation, particularly in terms of addressing mosquito larvae in overlooked places, such as the participants' own homes, for example, in flower vases and ant traps. PMID:25922218

  4. Insecticide resistance and, efficacy of space spraying and larviciding in the control of dengue vectors Aedes aegypti and Aedes albopictus in Sri Lanka.

    PubMed

    Karunaratne, S H P P; Weeraratne, T C; Perera, M D B; Surendran, S N

    2013-09-01

    Unprecedented incidence of dengue has been recorded in Sri Lanka in recent times. Source reduction and use of insecticides in space spraying/fogging and larviciding, are the primary means of controlling the vector mosquitoes Aedes aegypti and Ae. albopictus in the island nation. A study was carried out to understand insecticide cross-resistance spectra and mechanisms of insecticide resistance of both these vectors from six administrative districts, i.e. Kandy, Kurunegala, Puttalam, Gampaha, Ratnapura and Jaffna, of Sri Lanka. Efficacy of the recommended dosages of frequently used insecticides in space spraying and larviciding in dengue vector control programmes was also tested. Insecticide bioassay results revealed that, in general, both mosquito species were highly resistant to DDT but susceptible to propoxur and malathion except Jaffna Ae. aegypti population. Moderate resistance to malathion shown by Jaffna Ae. aegypti population correlated with esterase and malathion carboxylesterase activities of the population. High levels of acetylcholinesterase (AChE) insensitivity in the absence of malathion and propoxur resistance may be due to non-synaptic forms of AChE proteins. Moderate pyrethroid resistance in the absence of high monooxygenase levels indicated the possible involvement of 'kdr' type resistance mechanism in Sri Lankan dengue vectors. Results of the space spraying experiments revealed that 100% mortality at a 10 m distance and >50% mortality at a 50 m distance can be achieved with malathion, pesguard and deltacide even in a ground with dense vegetation. Pesguard and deltacide spraying gave 100% mortality up to 50 m distance in open area and areas with little vegetation. Both species gave >50% mortalities for deltacide at a distance of 75 m in a dense vegetation area. Larval bioassays conducted in the laboratory showed that a 1 ppm temephos solution can maintain a larval mortality rate of 100% for ten months, and the mortality rate declined to 0% in the eleventh month. In the field, where 1 ppm concentration is gradually decreased with water usage, 100% mortality was observed only for the first four months, <50% mortality for the next two months, and 0% mortality was observed eight months after the application of temephos. Deltacide can be effectively used for space spraying programmes in Sri Lanka. Larval control can be successfully achieved through temephos with public participation. PMID:25149242

  5. Use of Bacillus thuringiensis var israelensis as a viable option in an Integrated Malaria Vector Control Programme in the Kumasi Metropolis, Ghana

    PubMed Central

    2013-01-01

    Background Integrated Vector Control (IVC) remains the approach for managing the malaria-causing vector. The study investigated the contribution of Bacillus thuringiensis israelensis (Bti) in the control of malaria by targeting the larvae and also mapped and documented major breeding sites in the Kumasi metropolis, Ghana. Methods Using a hand held GPS receiver unit, major breeding sites within the metropolis were mapped out during the larval survey. Mosquito larvae were then collected from the breeding sites and reared in an insectary to obtain an F1 generation for laboratory bioassays. The minimum effective dosage of Bti Water Dispersible Granular (WDG) formulation was determined by a series of bioassays. Based on the results obtained in the laboratory, the optimum effective dosage of Bti formulations against naturally occurring larvae of the indigenous mosquito species was determined through open field trials. Results A total of 33 breeding sites were identified and geo-referenced during the larval surveys with the majority of the breeding sites located in the Asokwa sub-metropolis, Kumasi, Ghana. A Bti (3,000 International Toxic Unit (ITU)/mg) concentration of 0.026 mg/l resulted in 50% mortality whilst a concentration of 0.136 mg/l resulted in 95% mortality. Results from the open field trials with Bti showed that a dosage of 0.2 kg/ha is as effective as 0.4 kg/ha in suppressing late instars and resulting pupae. Conclusion This study reveals that Bti at a very low dosage of 0.2 kg/ha is highly effective against Anopheles larvae and therefore offers viable options for the management of vector mosquitoes. Further research is needed to extend this to the field in order to determine its ability to reduce malaria incidence. PMID:23607376

  6. Environments and trypanosomiasis risks for early herders in the later Holocene of the Lake Victoria basin, Kenya

    PubMed Central

    Chritz, Kendra L.; Marshall, Fiona B.; Zagal, M. Esperanza; Kirera, Francis; Cerling, Thure E.

    2015-01-01

    Specialized pastoralism developed ?3 kya among Pastoral Neolithic Elmenteitan herders in eastern Africa. During this time, a mosaic of hunters and herders using diverse economic strategies flourished in southern Kenya. It has been argued that the risk for trypanosomiasis (sleeping sickness), carried by tsetse flies in bushy environments, had a significant influence on pastoral diversification and migration out of eastern Africa toward southern Africa ?2 kya. Elmenteitan levels at Gogo Falls (ca. 1.9–1.6 kya) preserve a unique faunal record, including wild mammalian herbivores, domestic cattle and caprines, fish, and birds. It has been suggested that a bushy/woodland habitat that harbored tsetse fly constrained production of domestic herds and resulted in subsistence diversification. Stable isotope analysis of herbivore tooth enamel (n = 86) from this site reveals, instead, extensive C4 grazing by both domesticates and the majority of wild herbivores. Integrated with other ecological proxies (pollen and leaf wax biomarkers), these data imply an abundance of C4 grasses in the Lake Victoria basin at this time, and thus little risk for tsetse-related barriers to specialized pastoralism. These data provide empirical evidence for the existence of a grassy corridor through which small groups of herders could have passed to reach southern Africa. PMID:25775535

  7. Evaluating Liquid and Granular Bacillus thuringiensis var. israelensis Broadcast Applications for Controlling Vectors of Dengue and Chikungunya Viruses in Artificial Containers and Tree Holes.

    PubMed

    Harwood, James F; Farooq, Muhammad; Turnwall, Brent T; Richardson, Alec G

    2015-07-01

    The principal vectors of chikungunya and dengue viruses typically oviposit in water-filled artificial and natural containers, including tree holes. Despite the risk these and similar tree hole-inhabiting mosquitoes present to global public health, surprisingly few studies have been conducted to determine an efficient method of applying larvicides specifically to tree holes. The Stihl SR 450, a backpack sprayer commonly utilized during military and civilian vector control operations, may be suitable for controlling larval tree-hole mosquitoes, as it is capable of delivering broadcast applications of granular and liquid dispersible formulations of Bacillus thuringiensis var. israelensis (Bti) to a large area relatively quickly. We compared the application effectiveness of two granular (AllPro Sustain MGB and VectoBac GR) and two liquid (Aquabac XT and VectoBac WDG) formulations of Bti in containers placed on bare ground, placed beneath vegetative cover, and hung 1.5 or 3?m above the ground to simulate tree holes. Aedes aegypti (L.) larval mortality and Bti droplet and granule density data (when appropriate) were recorded for each formulation. Overall, granular formulations of Bti resulted in higher mortality rates in the simulated tree-hole habitats, whereas applications of granular and liquid formulations resulted in similar levels of larval mortality in containers placed on the ground in the open and beneath vegetation. PMID:26335473

  8. Impact of Insecticide Resistance on the Effectiveness of Pyrethroid-Based Malaria Vectors Control Tools in Benin: Decreased Toxicity and Repellent Effect

    PubMed Central

    Agossa, Fiacre R.; Gnanguenon, Virgile; Anagonou, Rodrigue; Azondekon, Roseric; Aïzoun, Nazaire; Sovi, Arthur; Oké-Agbo, Frédéric; Sèzonlin, Michel; Akogbéto, Martin C.

    2015-01-01

    Since the first evidence of pyrethroids resistance in 1999 in Benin, mutations have rapidly increased in mosquitoes and it is now difficult to design a study including a control area where malaria vectors are fully susceptible. Few studies have assessed the after effect of resistance on the success of pyrethroid based prevention methods in mosquito populations. We therefore assessed the impact of resistance on the effectiveness of pyrethroids based indoor residual spraying (IRS) in semi-field conditions and long lasting insecticidal nets (LLINs) in laboratory conditions. The results observed showed low repulsion and low toxicity of pyrethroids compounds in the test populations. The toxicity of pyrethroids used in IRS was significantly low with An. gambiae s.l (< 46%) but high for other predominant species such as Mansonia africana (93% to 97%). There were significant differences in terms of the repellent effect expressed as exophily and deterrence compared to the untreated huts (P<0.001). Furthermore, mortality was 23.71% for OlyseNet® and 39.06% for PermaNet®. However, with laboratory susceptible “Kisumu”, mortality was 100% for both nets suggesting a resistance within the wild mosquito populations. Thus treatment with pyrethroids at World Health Organization recommended dose will not be effective at reducing malaria in the coming years. Therefore it is necessary to study how insecticide resistance decreases the efficacy of particular pyrethroids used in pyrethroid-based vector control so that a targeted approach can be adopted. PMID:26674643

  9. Space treatments of insecticide for control of dengue virus vector Aedes aegypti in southern Mexico. I. Baseline penetration trials in open field and houses.

    PubMed

    Arrendondo-Jimenez, Juan I; Rivero, Norma E

    2006-06-01

    We studied the efficacy of space ultra-low volume treatments of 3 insecticides for the control of the dengue virus vector Aedes aegypti in southern Mexico. Insecticides tested were permethrin (Aqua-Reslin Super), d-phenothrin (Anvil), and cyfluthrin (Solfac), applied at rates of 10.87, 7.68, and 2 g/ha, respectively, by using London Fog, HP910-PHXL, or Micro-Gen pumps mounted on vehicles. Studies included 1) open field penetration tests and 2) house penetration tests. Open field tests indicated that Anvil and Solfac were more effective than Aqua-Reslin Super. In house tests, Anvil yielded the highest mosquito mortalities (>/=88%) of the three insecticides in the front porch, living room, bedroom, and backyard. Therefore, Anvil proved to be better than other insecticides evaluated to control Ae. aegypti in Chiapas, Mexico. PMID:17019777

  10. Toxicity effect of Delonix elata (Yellow Gulmohr) and predatory efficiency of Copepod, Mesocyclops aspericornis for the control of dengue vector, Aedes aegypti

    PubMed Central

    Vasugi, Chellamuthu; Kamalakannan, Siva; Murugan, Kadarkarai

    2013-01-01

    Objective To evaluate the toxicity, predatory efficiency of Delonix elata (D. elata) and Mesocyclops aspericornis (M. aspericornis) against dengue vector, Aedes aegypti (Ae. aegypti). Methods A mosquitocidal bioassay was conducted at different concentration of plant extract followed by WHO standard method. The probit analysis of each tested concentration and control were observed by using software SPSS 11 version package. The each tested concentration variable was assessed by DMRT method. The predatory efficiency of copepod was followed by Deo et al., 1988. The predator, M. aspericornis was observed for mortality, abnormalities, survival and swimming activity after 24 h treatment of plant and also predation on the mosquito larvae were observed. Results D. elata were tested for biological activity against the larvae, and pupae of Ae. aegypti. Significant mortality effects were observed in each life stage. The percentage of mortality was 100% in first and second instars whereas 96%, 92% in third and fourth instars. Fitted probit-mortality curves for larvae indicated the median and 90% lethal concentrations of D. elata for instars 1-4 to be 4.91 (8.13), 5.16 (8.44), 5.95 (7.76) and 6.87 (11.23), respectively. The results indicate that leaf extract exhibits significant biological activity against life stages. The present study revealed that D. elata is potentially important in the control of Ae. aegypti. Similar studies were conducted for predatory efficiency of Copepod, M. aspericornis against mosquito vector Ae. Aegypti. This study reported that the predatory copepod fed on 39% and 25% in I and III instar larvae of mosquito and in combined treatment of D. elata and copepod maximum control of mosquito larval states and at 83%, 80%, 75% and 53% in I, II, III and IV instars, respectively. Conclusions The combined action of plant extract and predatory copepod to effectively control mosquito population and reduce the dengue transmitting diseases.

  11. Noise generated by a flight weight, air flow control valve in a vertical takeoff and landing aircraft thrust vectoring system

    NASA Technical Reports Server (NTRS)

    Huff, Ronald G.

    1989-01-01

    Tests were conducted in the NASA Lewis Research Center's Powered Lift Facility to experimentally evaluate the noise generated by a flight weight, 12 in. butterfly valve installed in a proposed vertical takeoff and landing thrust vectoring system. Fluctuating pressure measurements were made in the circular duct upstream and downstream of the valve. This data report presents the results of these tests. The maximum overall sound pressure level is generated in the duct downstream of the valve and reached a value of 180 dB at a valve pressure ratio of 2.8. At the higher valve pressure ratios the spectra downstream of the valve is broad banded with its maximum at 1000 Hz.

  12. Vector-based one-line model for shoreline evolution: application to explore wave-climate control on bay morphology

    NASA Astrophysics Data System (ADS)

    Hurst, M. D.; Barkwith, A.; Thomas, C.; Ellis, M. A.

    2014-12-01

    Exploratory one-line coastal models have been used to investigate the formation and evolution of coastal geomorphic features developed on sandy coasts, and are often applied by engineers for coastline management. Existing one-line models discretise the coast in a Cartesian coordinate system, limiting the evolution of the coastline to the cardinal directions, inhibiting some models from handling complex coastal geometries with high plan-form curvature. We developed a vector-based one-line model using local shoreline coordinates in order to evolve complex coastline geometries more effectively, including islands. The vector-based approach aids model efficiency whilst allowing complex coastal forms such as headland bay beaches, spits, sand waves and islands to be modelled. The coastline is discretised into polygonal, trapezoid or triangular cells depending on the coastline geometry being considered and the shoreface evolves normal to the local shoreline configuration. As in existing one-line models, changes in shoreline position are driven by gradients in alongshore sediment flux, calculated as a function of breaking wave conditions and integrated across the shoreface depth (in this case using the CERC equation). Waves are transformed following Airy wave theory, assuming that depth contours are locally shore-parallel. Additional rules for refraction and diffraction in the shadow of headlands or coastal structures have also been incorporated. We demonstrate the model's potential by applying it to the development of concave and convex shoreline features. In particular we focus on the formation and evolution of headland bay beaches in the lee of headlands or sea defences, exploring the influence of varying offshore wave climates on emergent morphologically steady crenulate bay forms. We compare numerical modelling results to predictions of empirical models for the equilibrium form of crenulate bays as well as examples from nature.

  13. Effective control of dengue vectors with curtains and water container covers treated with insecticide in Mexico and Venezuela: cluster randomised trials

    PubMed Central

    Kroeger, Axel; Lenhart, Audrey; Ochoa, Manuel; Villegas, Elci; Levy, Michael; Alexander, Neal; McCall, P J

    2006-01-01

    Objectives To measure the impact on the dengue vector population (Aedes aegypti) and disease transmission of window curtains and water container covers treated with insecticide. Design Cluster randomised controlled trial based on entomological surveys and, for Trujillo only, serological survey. In addition, each site had a non-randomised external control. Setting 18 urban sectors in Veracruz (Mexico) and 18 in Trujillo (Venezuela). Participants 4743 inhabitants (1095 houses) in Veracruz and 5306 inhabitants (1122 houses) in Trujillo. Intervention Sectors were paired according to entomological indices, and one sector in each pair was randomly allocated to receive treatment. In Veracruz, the intervention comprised curtains treated with lambdacyhalothrin and water treatment with pyriproxyfen chips (an insect growth regulator). In Trujillo, the intervention comprised curtains treated with longlasting deltamethrin (PermaNet) plus water jar covers of the same material. Follow-up surveys were conducted at intervals, with the final survey after 12 months in Veracruz and nine months in Trujillo. Main outcome measures Reduction in entomological indices, specifically the Breteau and house indices. Results In both study sites, indices at the end of the trial were significantly lower than those at baseline, though with no significant differences between control and intervention arms. The mean Breteau index dropped from 60% (intervention clusters) and 113% (control) to 7% (intervention) and 12% (control) in Veracruz and from 38% to 11% (intervention) and from 34% to 17% (control) in Trujillo. The pupae per person and container indices showed similar patterns. In contrast, in nearby communities not in the trial the entomological indices followed the rainfall pattern. The intervention reduced mosquito populations in neighbouring control clusters (spill-over effect); and houses closer to treated houses were less likely to have infestations than those further away. This created a community effect whereby mosquito numbers were reduced throughout the study site. The observed effects were probably associated with the use of materials treated with insecticide at both sites because in Veracruz, people did not accept and use the pyriproxyfen chips. Conclusion Window curtains and domestic water container covers treated with insecticide can reduce densities of dengue vectors to low levels and potentially affect dengue transmission. PMID:16735334

  14. The Repellent DEET Potentiates Carbamate Effects via Insect Muscarinic Receptor Interactions: An Alternative Strategy to Control Insect Vector-Borne Diseases

    PubMed Central

    Abd-Ella, Aly; Stankiewicz, Maria; Mikulska, Karolina; Nowak, Wieslaw; Pennetier, Cédric; Goulu, Mathilde; Fruchart-Gaillard, Carole; Licznar, Patricia; Apaire-Marchais, Véronique; List, Olivier; Corbel, Vincent; Servent, Denis; Lapied, Bruno

    2015-01-01

    Insect vector-borne diseases remain one of the principal causes of human mortality. In addition to conventional measures of insect control, repellents continue to be the mainstay for personal protection. Because of the increasing pyrethroid-resistant mosquito populations, alternative strategies to reconstitute pyrethroid repellency and knock-down effects have been proposed by mixing the repellent DEET (N,N-Diethyl-3-methylbenzamide) with non-pyrethroid insecticide to better control resistant insect vector-borne diseases. By using electrophysiological, biochemichal, in vivo toxicological techniques together with calcium imaging, binding studies and in silico docking, we have shown that DEET, at low concentrations, interacts with high affinity with insect M1/M3 mAChR allosteric site potentiating agonist effects on mAChRs coupled to phospholipase C second messenger pathway. This increases the anticholinesterase activity of the carbamate propoxur through calcium-dependent regulation of acetylcholinesterase. At high concentrations, DEET interacts with low affinity on distinct M1/M3 mAChR site, counteracting the potentiation. Similar dose-dependent dual effects of DEET have also been observed at synaptic mAChR level. Additionally, binding and in silico docking studies performed on human M1 and M3 mAChR subtypes indicate that DEET only displays a low affinity antagonist profile on these M1/M3 mAChRs. These results reveal a selective high affinity positive allosteric site for DEET in insect mAChRs. Finally, bioassays conducted on Aedes aegypti confirm the synergistic interaction between DEET and propoxur observed in vitro, resulting in a higher mortality of mosquitoes. Our findings reveal an unusual allosterically potentiating action of the repellent DEET, which involves a selective site in insect. These results open exciting research areas in public health particularly in the control of the pyrethroid-resistant insect-vector borne diseases. Mixing low doses of DEET and a non-pyrethroid insecticide will lead to improvement in the efficiency treatments thus reducing both the concentration of active ingredients and side effects for non-target organisms. The discovery of this insect specific site may pave the way for the development of new strategies essential in the management of chemical use against resistant mosquitoes. PMID:25961834

  15. Exploring the origin and degree of genetic isolation of Anopheles gambiae from the islands of São Tomé and Príncipe, potential sites for testing transgenic-based vector control

    PubMed Central

    Marshall, Jonathon C; Pinto, João; Charlwood, Jacques Derek; Gentile, Gabriele; Santolamazza, Federica; Simard, Frèdèric; Della Torre, Alessandra; Donnelly, Martin J; Caccone, Adalgisa

    2008-01-01

    The evolutionary processes at play between island and mainland populations of the malaria mosquito vector Anopheles gambiae sensu stricto are of great interest as islands may be suitable sites for preliminary application of transgenic-based vector control strategies. São Tomé and Príncipe, located off the West African coast, have received such attention in recent years. This study investigates the degree of isolation of An. gambiae s.s. populations between these islands and the mainland based on mitochondrial and ribosomal DNA molecular data. We identify possible continental localities from which these island populations derived. For these purposes, we used FST values, haplotype networks, and nested clade analysis to estimate migration rates and patterns. Haplotypes from both markers are geographically widespread across the African continent. Results indicate that the populations from São Tomé and Príncipe are relatively isolated from continental African populations, suggesting they are promising sites for test releases of transgenic individuals. These island populations are possibly derived from two separate continental migrations. This result is discussed in the context of the history of the African slave trade with respect to São Tomé and Príncipe. PMID:25567803

  16. Sylvatic focus of American Trypanosomiasis in the State of Morelos, Mexico.

    PubMed

    Villegas-García, J C; Santillán-Alarcón, S

    2001-06-01

    Wild vectors and reservoir hosts of Trypanosoma cruzi were surveyed from February 1993 to June 1994 in Ticumán (18 degrees 46'N, 99 degrees 07'W), Mexico (Deciduous Tropical Forest). Direct faeces examination showed that 87% of Triatoma pallidipennis hosted the parasite; T. cruzi forms were present in cultures inoculated with faeces of fifty 67% triatomine bugs and thirty CD-1 strain mice (10 d old) inoculated (peritoneum) with faeces of positive insects T. cruzi amastigotes were found in heart 67%, kidneys 47%, liver 80%, lungs 50%, oesophagus 60%, skin 23%, spleen 73% and stomach 60%. T. cruzi was isolated by direct blood examination from seven 21% chiropterans and five 38% rodents and T. cruzi forms were present in cultures inoculated with blood of twenty-three 68% chiropterans and seven 54% rodents and T. cruzi amastigotes were seen in the kidneys of one 3% chiropterans and four 31% rodents and only in one Pteronotus parnellii mexicanus, organisms were seen in skin 2%. There was no association between organs and T. cruzi infection (p > 0.05). PMID:11935921

  17. Safety, Pharmacokinetic, and Efficacy Studies of Oral DB868 in a First Stage Vervet Monkey Model of Human African Trypanosomiasis

    PubMed Central

    Thuita, John K.; Wolf, Kristina K.; Murilla, Grace A.; Liu, Qiang; Mutuku, James N.; Chen, Yao; Bridges, Arlene S.; Mdachi, Raymond E.; Ismail, Mohamed A.; Ching, Shelley; Boykin, David W.; Hall, James Edwin; Tidwell, Richard R.; Paine, Mary F.; Brun, Reto; Wang, Michael Zhuo

    2013-01-01

    There are no oral drugs for human African trypanosomiasis (HAT, sleeping sickness). A successful oral drug would have the potential to reduce or eliminate the need for patient hospitalization, thus reducing healthcare costs of HAT. The development of oral medications is a key objective of the Consortium for Parasitic Drug Development (CPDD). In this study, we investigated the safety, pharmacokinetics, and efficacy of a new orally administered CPDD diamidine prodrug, 2,5-bis[5-(N-methoxyamidino)-2-pyridyl]furan (DB868; CPD-007-10), in the vervet monkey model of first stage HAT. DB868 was well tolerated at a dose up to 30 mg/kg/day for 10 days, a cumulative dose of 300 mg/kg. Mean plasma levels of biomarkers indicative of liver injury (alanine aminotransferase, aspartate aminotransferase) were not significantly altered by drug administration. In addition, no kidney-mediated alterations in creatinine and urea concentrations were detected. Pharmacokinetic analysis of plasma confirmed that DB868 was orally available and was converted to the active compound DB829 in both uninfected and infected monkeys. Treatment of infected monkeys with DB868 began 7 days post-infection. In the infected monkeys, DB829 attained a median Cmax (dosing regimen) that was 12-fold (3 mg/kg/day for 7 days), 15-fold (10 mg/kg/day for 7 days), and 31-fold (20 mg/kg/day for 5 days) greater than the IC50 (14 nmol/L) against T. b. rhodesiense STIB900. DB868 cured all infected monkeys, even at the lowest dose tested. In conclusion, oral DB868 cured monkeys with first stage HAT at a cumulative dose 14-fold lower than the maximum tolerated dose and should be considered a lead preclinical candidate in efforts to develop a safe, short course (5–7 days), oral regimen for first stage HAT. PMID:23755309

  18. Does Cattle Milieu Provide a Potential Point to Target Wild Exophilic Anopheles arabiensis (Diptera: Culicidae) with Entomopathogenic Fungus? A Bioinsecticide Zooprophylaxis Strategy for Vector Control

    PubMed Central

    Lyimo, Issa N.; Ng'habi, Kija R.; Mpingwa, Monica W.; Daraja, Ally A.; Mwasheshe, Dickson D.; Nchimbi, Nuru S.; Lwetoijera, Dickson W.; Mnyone, Ladslaus L.

    2012-01-01

    Background. Anopheles arabiensis is increasingly dominating malaria transmission in Africa. The exophagy in mosquitoes threatens the effectiveness of indoor vector control strategies. This study aimed to evaluate the effectiveness of fungus against An. arabiensis when applied on cattle and their environments. Methods. Experiments were conducted under semi-field and small-scale field conditions within Kilombero valley. The semi-field reared females of 5–7 days old An. arabiensis were exposed to fungus-treated and untreated calf. Further, wild An. arabiensis were exposed to fungus-treated calves, mud-huts, and their controls. Mosquitoes were recaptured the next morning and proportion fed, infected, and survived were evaluated. Experiments were replicated three times using different individuals of calves. Results. A high proportion of An. arabiensis was fed on calves (>0.90) and become infected (0.94) while resting on fungus-treated mud walls than on other surfaces. However, fungus treatments reduced fecundity and survival of mosquitoes. Conclusion. This study demonstrates for the first time the potential of cattle and their milieu for controlling An. arabiensis. Most of An. arabiensis were fed and infected while resting on fungus-treated mud walls than on other surfaces. Fungus treatments reduced fecundity and survival of mosquitoes. These results suggest deployment of bioinsecticide zooprophylaxis against exophilic An. arabiensis. PMID:22934152

  19. [Integrated vector control methods and the threat of dengue hemorrhagic fever in the tropical zone of the Pacific Ocean].

    PubMed

    Laird, M

    1984-01-01

    Together with a story of the author's earliest visit to Leningrad and first meeting with the late Academician E. N. Pavlovsky , this contribution outlines subsequent developments concerning innovative approaches to the control of Culicidae of medical importance, with particular attention to a major field trial on the atoll of Funafuti , Tuvalu . PMID:6374585

  20. Early biting of the Anopheles gambiae s.s. and its challenges to vector control using insecticide treated nets in western Kenya highlands.

    PubMed

    Wamae, P M; Githeko, A K; Otieno, G O; Kabiru, E W; Duombia, S O

    2015-10-01

    Long term use of insecticides in malaria vector control has been shown to alter the behavior of vectors. Such behavioral shifts have the potential of undermining the effectiveness of insecticide-based control interventions. The effects of insecticide treated nets (ITNs) use on the composition, biting/feeding and sporozoite rates of Anopheles gambiae s.l. mosquitoes in Musilongo village, Vihiga County of western Kenya highlands were investigated. Adult mosquitoes were collected in selected sleeping spaces inside six randomly selected houses using miniature Centre for Disease Control and Prevention (CDC) light traps. Mosquito sampling in each house was conducted twice every week for 16 consecutive months (May 2010-August 2012). At each sampling a single trap was set in the selected space inside each house such that it collected mosquitoes alternatively from 18:00 to 21:00h and 21:00 to 06:00h every week. All collected mosquitoes were morphologically identified. Female Anopheles mosquitoes were classified according to their physiological status as unfed, fed, partially gravid and gravid, sorted and counted. Members of the A. gambiae complex were identified using a Polymerase chain reaction (PCR) method. Enzyme-linked-immunosorbent assay (ELISA) was used to determine blood meal sources and Plasmodium infection rates in A. gambiae s.l. mosquitoes. Blood meal tests were conducted on DNA extracted from gut contents of blood fed A. gambiae s.l. The head and thorax section of dried samples of A. gambiae s.l. were used in testing for the presence of Plasmodium falciparum (Pf) sporozoites. Overall, 735 adult female Anopheles comprising 708 [96.3%] A. gambiae s.l. and 27 [3.7%] Anopheles funestus mosquitoes were collected. A. gambiae s.l. population collected comprised, 615 [86.9%] unfed and 38 [5.4%] fed adult mosquitoes. The rest were either partially or fully gravid. The proportion of A. gambiae s.l. biting indoors within 18:00-21:00h was 15.8% (103/653) at a rate of 3.2bites per person per hour compared to 84.2% biting from 21:00-06:00h at a rate of 3.8 bites/per/h. An estimated 97.7% A. gambiae ss and 2.3% A. arabiensis constituted the indoor biting A. gambiae s.l. The population of An. gambiae s.l. biting from 18:00 to 21:00h had a Plasmodium faciparum (pf) sporozoite rate of 3.8% compared to 3.5% observed in populations biting within 21:00-06:00h. Human blood constituted 89% of An. gambiae s.l. blood meal sources. The risk of malaria transmission from 21:00 to 06:00h was approximately 5 fold the risk within 18:00-21:00h. Majority of the infective female A. gambiae s.l. adults were biting deep into the night than in the early hours of the night. Humans remain the preferred source of blood meal for A. gambiae s.s. the dominant malaria vector in the highlands. ITNs remain a fundamental control intervention against malaria transmission since female blood seekers were more during bed time than pre-bed time. Advocacy on enhanced net availability, integrity and usage in Kenyan highlands can reduce Pf transmission. Additional complementary interventions are required to control the biting and parasite transmission encountered before bed-time. PMID:26209103

  1. Fast Fourier and discrete wavelet transforms applied to sensorless vector control induction motor for rotor bar faults diagnosis.

    PubMed

    Talhaoui, Hicham; Menacer, Arezki; Kessal, Abdelhalim; Kechida, Ridha

    2014-09-01

    This paper presents new techniques to evaluate faults in case of broken rotor bars of induction motors. Procedures are applied with closed-loop control. Electrical and mechanical variables are treated using fast Fourier transform (FFT), and discrete wavelet transform (DWT) at start-up and steady state. The wavelet transform has proven to be an excellent mathematical tool for the detection of the faults particularly broken rotor bars type. As a performance, DWT can provide a local representation of the non-stationary current signals for the healthy machine and with fault. For sensorless control, a Luenberger observer is applied; the estimation rotor speed is analyzed; the effect of the faults in the speed pulsation is compensated; a quadratic current appears and used for fault detection. PMID:25004798

  2. Nanoformulation of poly(ethylene glycol) polymerized organic insect repellent by PIT emulsification method and its application for Japanese encephalitis vector control.

    PubMed

    Balaji, A P B; Mishra, Prabhakar; Suresh Kumar, R S; Mukherjee, Amitava; Chandrasekaran, Natarajan

    2015-04-01

    The utilization of increased dosage of insect repellents to overcome mosquito resistance has raised environmental concerns globally. In accord to this, we have formulated an efficacious, water-dispersive, nanometric formulation of a poor water-soluble insect repellent, diethylphenylacetamide (DEPA) by poly(ethylene glycol) (PEG) polymerization followed by PIT emulsification method. The critical micelle concentration of PEG in the spontaneously emulsified conventional DEPA droplets was determined, based on the droplets physical stability. Subjecting them to PIT emulsification yielded monodispersed polymeric nanomicelles of DEPA (Nano DEPA) with hydrodynamic mean diameter of 153.74 nm. The high-resolution scanning and transmission electron microscopic studies revealed the characteristic core-shell structure of micelle. The comparative efficacy of Bulk DEPA and Nano DEPA was evaluated by larvicidal and WHO cone bioassay against the Japanese encephalitis vector Culex tritaeniorhynchus. The median lethal concentrations (48 h) for 3rd instars C. tritaeniorhynchus larvae were found to be 0.416 mg/L for Bulk DEPA and 0.052 mg/L for Nano DEPA, respectively. The median knockdown concentrations (60 min) for the two to three-day-old, sucrose-fed, female adult mosquitoes were 5.372% (v/v) and 3.471% (v/v) for Bulk and Nano DEPA, respectively. Further investigation by histopathological and biochemical studies propound that Nano DEPA exerted better bioefficacy as comparative to its bulk form even at minimal exposure concentrations. Hence, Nano DEPA will serve as an effective alternate in controlling the vector expansion with reduced dosage. PMID:25766922

  3. Molecular epidemiology of trypanosomiasis in Ugandan cattle during the Stamping Out Sleeping Sickness control programme, 2006 – 2008 

    E-print Network

    Hamill, Louise Claire

    2013-06-29

    Over the past two decades movement of cattle towards the north of Uganda has enabled the Trypanosoma brucei rhodesiense focus in south-eastern Uganda to spread into previously unaffected districts. This thesis brings ...

  4. Contrasting genetic structure between mitochondrial and nuclear markers in the dengue fever mosquito from Rio de Janeiro: implications for vector control

    PubMed Central

    Raši?, Gordana; Schama, Renata; Powell, Rosanna; Maciel-de Freitas, Rafael; Endersby-Harshman, Nancy M; Filipovi?, Igor; Sylvestre, Gabriel; Máspero, Renato C; Hoffmann, Ary A

    2015-01-01

    Dengue is the most prevalent global arboviral disease that affects over 300 million people every year. Brazil has the highest number of dengue cases in the world, with the most severe epidemics in the city of Rio de Janeiro (Rio). The effective control of dengue is critically dependent on the knowledge of population genetic structuring in the primary dengue vector, the mosquito Aedes aegypti. We analyzed mitochondrial and nuclear genomewide single nucleotide polymorphism markers generated via Restriction-site Associated DNA sequencing, as well as traditional microsatellite markers in Ae. aegypti from Rio. We found four divergent mitochondrial lineages and a strong spatial structuring of mitochondrial variation, in contrast to the overall nuclear homogeneity across Rio. Despite a low overall differentiation in the nuclear genome, we detected strong spatial structure for variation in over 20 genes that have a significantly altered expression in response to insecticides, xenobiotics, and pathogens, including the novel biocontrol agent Wolbachia. Our results indicate that high genetic diversity, spatially unconstrained admixing likely mediated by male dispersal, along with locally heterogeneous genetic variation that could affect insecticide resistance and mosquito vectorial capacity, set limits to the effectiveness of measures to control dengue fever in Rio. PMID:26495042

  5. Contrasting genetic structure between mitochondrial and nuclear markers in the dengue fever mosquito from Rio de Janeiro: implications for vector control.

    PubMed

    Raši?, Gordana; Schama, Renata; Powell, Rosanna; Maciel-de Freitas, Rafael; Endersby-Harshman, Nancy M; Filipovi?, Igor; Sylvestre, Gabriel; Máspero, Renato C; Hoffmann, Ary A

    2015-10-01

    Dengue is the most prevalent global arboviral disease that affects over 300 million people every year. Brazil has the highest number of dengue cases in the world, with the most severe epidemics in the city of Rio de Janeiro (Rio). The effective control of dengue is critically dependent on the knowledge of population genetic structuring in the primary dengue vector, the mosquito Aedes aegypti. We analyzed mitochondrial and nuclear genomewide single nucleotide polymorphism markers generated via Restriction-site Associated DNA sequencing, as well as traditional microsatellite markers in Ae. aegypti from Rio. We found four divergent mitochondrial lineages and a strong spatial structuring of mitochondrial variation, in contrast to the overall nuclear homogeneity across Rio. Despite a low overall differentiation in the nuclear genome, we detected strong spatial structure for variation in over 20 genes that have a significantly altered expression in response to insecticides, xenobiotics, and pathogens, including the novel biocontrol agent Wolbachia. Our results indicate that high genetic diversity, spatially unconstrained admixing likely mediated by male dispersal, along with locally heterogeneous genetic variation that could affect insecticide resistance and mosquito vectorial capacity, set limits to the effectiveness of measures to control dengue fever in Rio. PMID:26495042

  6. Cost of integrated vector control with improved sanitation and road infrastructure coupled with the use of slow-release Bacillus sphaericus granules in a tropical urban setting.

    PubMed

    Skovmand, Ole; Ouedraogo, Thierry D A; Sanogo, Edith; Samuelsen, Helle; Toé, Lea Paré; Bosselmann, Rune; Czajkowski, Tonny; Baldet, Thierry

    2011-07-01

    A field test of integrated vector control was conducted in a tropical urban setting with a combination of a floating, slow-release, granular formulation of Bacillus sphaericus and environmental engineering measures (renovation of roads, collective water pumps, and cesspool lids). The targets were Culex quinquefasciatus and Anopheles gambiae in the two biggest towns of Burkina Faso (West Africa). Within the intervention zone, water pumping stations were improved and the surroundings drained to prevent the accumulation of stagnant water. Roads were leveled and given either simple gutters on each side or a concrete channel on one side to drain runoff water. Garbage containers were installed to provide an alternative to the drainage channels for waste disposal. Septic tanks were modified so that they could be emptied without destroying their lid. This study showed that it is possible to implement mosquito control in a tropical urban environment with teams of young people rapidly trained to apply a biological larvicide without any tools other than an iron bar to lift cesspool lids. Environmental improvements were initially costly, but demanded little subsequent expenditure. Local inhabitants' committees were mobilized to provide people with information and monitor the efficacy of the measures. Compared with what people spent individually on mosquito prevention and malaria medicine, these measures were not expensive, but many expected the community to pay for them from existing taxes, e.g., for water treatment and disposal. The necessary funding and logistics require a municipal organization with neighborhood support, if the measures are to be effective. PMID:21845940

  7. [Human African trypanosomiasis in the mangrove forest in Guinea: epidemiological and clinical features in two adjacent outbreak areas].

    PubMed

    Camara, M; Kaba, D; KagbaDouno, M; Sanon, J R; Ouendeno, F F; Solano, P

    2005-01-01

    The purpose of this study carried out in two adjacent areas of the coastal mangrove forest of Guinea (Dubreka and Boffa) was to screen the population for disease, provide information on human African trypanosomiasis (HAT, a.k.a. sleeping sickness) and compare the epidemiologic and clinical features with those of outbreak areas in the Ivory Coast where more data is currently available. Cases of HAT were confirmed by parasitological testing after active medical work-up (91 of 9637 patients examined). Five cases were confirmed in patients in treatment centers. Of the first 57 cases admitted for treatment in the Dubreka and Boffa centers, 29 were responded to a clinical and epidemiological questionnaire and underwent thorough clinical examination. Disease stage was determined by cytochemical testing of cerebrospinal fluid. As in outbreak areas of the Ivory Coast, sleeping sickness in Dubreka and Boffa is a rural disease mainly affecting the working population. Most cases identified in Guinea involved men and women working in farming, fishing, or salt extraction. However unlike Ivory Coast outbreak areas where ethnic diversity related to share cropping is considered to play a major role in maintaining endemicity, almost all patients in our study (98%) were from the native Soussou population that is self employed and lives in villages with no immigrant population. While clinical symptoms observed in these patients were not different from those reported elsewhere, there was a high frequency of cervical adenopathy (93%). This finding could provide a useful diagnostic sign for screening populations living in these mangrove forest regions and as a source for parasitological diagnosis as shown by the fact that 88.5% of patients were screened on the basis of lymph node fluid specimens. Most patients including among those identified by active work-up (5%) were in the meningo-encephalitis phase of the disease (98%). The findings of this study underline the need not only to continue surveillance in these regions but also to extend surveillance throughout the country as a means of avoiding recrudescence and extension of the disease. PMID:16038356

  8. Chikungunya virus-vector interactions.

    PubMed

    Coffey, Lark L; Failloux, Anna-Bella; Weaver, Scott C

    2014-11-01

    Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed. PMID:25421891

  9. Chikungunya Virus–Vector Interactions

    PubMed Central

    Coffey, Lark L.; Failloux, Anna-Bella; Weaver, Scott C.

    2014-01-01

    Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed. PMID:25421891

  10. A link between chemokine levels and disease severity in human African trypanosomiasis.

    PubMed

    Courtioux, Bertrand; Boda, Caroline; Vatunga, Gédéon; Pervieux, Lynda; Josenando, Théophile; M'Eyi, Paulette Mengue; Bouteille, Bernard; Jauberteau-Marchan, Marie-Odile; Bisser, Sylvie

    2006-08-01

    Trypanosoma brucei gambiense infection is an important public health challenge in sub-Saharan Africa. This parasitic disease is difficult to diagnose due to insidious clinical signs and transient parasitaemias. The clinical course is marked by two stages of increasing disease severity. An early systemic parasitic invasion is followed by the development of a progressive meningo-encephalitis. During this latter stage, a broad spectrum of neurological signs appears, which finally lead to a demyelinating and fatal stage if untreated. Treatment is toxic and difficult to administer when the CNS is invaded. Therefore, accurate diagnostic methods for stage determination are needed. The classically used criteria are not sufficiently specific and mechanisms of parasite invasion through the blood-brain barrier remain poorly understood. As cytokines/chemokines are involved in the early recruitment of leukocytes into the CNS, this study has focused on their potential value to define the onset of CNS involvement. Levels of monocyte chemoattractant protein-1/CCL-2, macrophage inflammatory protein-1alpha/CCL-3, IL-8/CXCL-8, regulated upon activation T cell expressed and secreted (RANTES)/CCL-5 and IL-1beta were measured in paired sera and CSF from 57 patients and four controls. Patients were classified into three groups (stage 1, intermediate and stage 2) according to current field criteria for stage determination (CSF cell count, presence of trypanosomes in CSF and neurological signs). In sera, cytokine/chemokine levels were poorly related to disease stage. Only CXCL-8 was higher in stage 1 patients when compared with stage 2 and CCL-5 was higher in controls when compared with patients. In contrast, in CSF the expression of the selected cytokines, except CCL-5, was associated with the presence of neurological signs, demonstrating their diagnostic value. We observed a relationship between the presence of trypanosomes or trypanosome-related compounds in CSF and levels of IL-1beta, CXCL-8, CCL-2 and CCL-3. These cytokines and chemokines may be triggered by the parasite and hence are potential markers of CNS invasion. PMID:16765963

  11. UNDERSTANDING THE VECTOR IN ORDER TO PLAN EFFECTIVE TOBACCO CONTROL POLICIES: AN ANALYSIS OF CONTEMPORARY TOBACCO INDUSTRY MATERIALS

    PubMed Central

    Gilmore, Anna B

    2013-01-01

    Background This paper builds on tobacco document research by analysing contemporary materials to explore how the global tobacco market has changed, how transnational tobacco companies (TTCs) are responding and identify the implications for tobacco control. Methods Analysis of a variety of materials including tobacco company annual reports, investor relations materials, financial analyst reports, market research reports and data. Findings Once China, where TTCs have little market share, is excluded, global cigarette volumes are already declining. Nevertheless, industry profits continue to increase. This pattern is explained by TTCs’ pricing power - their ability to increase prices faster than volumes fall; a consequence of market failure. Pricing power is now fundamental to the TTCs’ long-term future. Consequently, and in light of growing regulations, the TTCs’ business model is changing. Product innovation is now a key marketing technique used to drive consumers to buy more expensive (ie profitable) premium cigarettes. Contrary to established wisdom, high tobacco excise rates, particularly where increases in excise are gradual, can benefit TTCs by enabling price (profit) increases to be disguised. Large intermittent tax increases likely have a greater public health benefit. TTC investments in smokeless appear designed to eliminate competition between smokeless and cigarettes, thereby increasing TTCs’ pricing power while enabling them to harness the rhetoric of harm reduction. Conclusions Monitoring TTCs can inform effective policy development. The TTC’s value maximising approach suggests that a ban on product innovation and more informed tobacco excise policies are needed. PMID:22345234

  12. In vitro phytotherapy of vector snails by binary combinations of larvicidal active components in effective control of fascioliasis.

    PubMed

    Sunita, Kumari; Kumar, Pradeep; Singh, Vinay Kumar; Singh, Dinesh Kumar

    2013-01-01

    A food-borne trematode infection fascioliasis is one among common public health problems worldwide. It caused a great economic loss for the human race. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. The life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria inside of the snail Lymnaea acuminata. In vitro toxicity of different binary combinations (1:1 ratio) of plant-derived larvicidal active components such as citral, ferulic acid, umbelliferone, azadirachtin and allicin against Fasciola redia and cercaria were tested. The mortality of larvae was observed at 2h, 4h, 6h and 8h of treatment. In in vitro condition azadirachtin + allicin (1:1 ratio) was highly toxic against redia and cercaria (8h LC50 0.006 and 0.005 mg/L). Toxicity of citral + ferulic acid was lowest against redia and cercaria larvae. PMID:24037283

  13. Spatial and temporal variations relevant to tsetse control in the Bipindi focus of southern Cameroon

    PubMed Central

    2013-01-01

    Background Human African Trypanosomiasis (HAT) remains a public health problem in many poor countries. Due to lack of financial resources in these countries, cost-effective strategies are needed for efficient control of this scourge, especially the tsetse vector. It was shown that perennial water sources maintain a favourable biotope for tsetse flies and thus the transmission dynamics of sleeping sickness. The present paper aimed at assessing the transmission dynamics of HAT in a forest environment where the hydrographic network is important. Methods Two entomological surveys were carried out in July 2009 and March 2010 in the Bipindi sleeping sickness focus of the South Region of Cameroon. Entomological and parasitological data were collected during both trapping periods (including the climate variations throughout a year) and compared to each other. The level of risk for transmission of the disease during each trapping period was also evaluated at the trap level and materialised on the map of the Bipindi focus. Results Glossina palpalis palpalis was the most prevalent tsetse fly species captured in this focus. The overall densities of tsetse flies as well as the risk for transmission of HAT in the Bipindi focus were significantly higher in July than in March. At the trap level, we observed that these parameters were almost constant, whatever the trapping period, when the biotope included perennial water sources. Conclusions This study shows that the spatial distribution of traps, as well as the temporal climatic variations might influence entomological and parasitological parameters of HAT and that the presence of perennial water sources in biotopes would favour the development of tsetse flies and thus the transmission of sleeping sickness. These factors should, therefore, be taken into account in order to provide more efficient vector control. PMID:23815985

  14. Deriving meteorological variables across Africa for the study and control of vector-borne disease: a comparison of remote sensing and spatial interpolation of climate

    PubMed Central

    Hay, S. I.; Lennon, J. J.

    2012-01-01

    Summary This paper presents the results of an investigation into the utility of remote sensing (RS) using meteorological satellites sensors and spatial interpolation (SI) of data from meteorological stations, for the prediction of spatial variation in monthly climate across continental Africa in 1990. Information from the Advanced Very High Resolution Radiometer (AVHRR) of the National Oceanic and Atmospheric Administration’s (NOAA) polar-orbiting meteorological satellites was used to estimate land surface temperature (LST) and atmospheric moisture. Cold cloud duration (CCD) data derived from the High Resolution Radiometer (HRR) on-board the European Meteorological Satellite programme’s (EUMETSAT) Meteosat satellite series were also used as a RS proxy measurement of rainfall. Temperature, atmospheric moisture and rainfall surfaces were independently derived from SI of measurements from the World Meteorological Organization (WMO) member stations of Africa. These meteorological station data were then used to test the accuracy of each methodology, so that the appropriateness of the two techniques for epidemiological research could be compared. SI was a more accurate predictor of temperature, whereas RS provided a better surrogate for rainfall; both were equally accurate at predicting atmospheric moisture. The implications of these results for mapping short and long-term climate change and hence their potential for the study and control of disease vectors are considered. Taking into account logistic and analytical problems, there were no clear conclusions regarding the optimality of either technique, but there was considerable potential for synergy. PMID:10203175

  15. The use of wide-mesh gauze impregnated with lambda-cyhalothrin covering wall openings in huts as a vector control method in Suriname.

    PubMed

    Voorham, J

    1997-02-01

    An alternative vector control method, using lambda-cyhalothrin impregnated wide-mesh gauze covering openings in the walls of the houses was developed in an area in the Eastern part of the interior of Suriname. Experimental hut observations showed that Anopheles darlingi greatly reduced their biting activity (99-100%) during the first 5 months after impregnation. A model assay showed high mortality both of mosquitoes repelled by the gauze as well as of those that succeeded in getting through it. A field application test in 270 huts showed good acceptance by the population and good durability of the applied gauze. After introducing the method in the entire working area, replacing DDT residual housespraying, the malaria prevalence, of 25-37% before application dropped and stabilized at between 5 and 10% within one year. The operational costs were less than those of the previously used DDT housespraying program, due to a 50% reduction in the cost of materials used. The method using wide-mesh gauze impregnated with lambda-cyhalothrin strongly affects the behavior of An. darlingi. It is important to examine the effect of the method on malaria transmission further, since data indirectly obtained suggest substantial positive results. PMID:9430921

  16. Synergistic action of octopamine receptor agonists on the activity of selected novel insecticides for control of dengue vector Aedes aegypti (Diptera: Culicidae) mosquito.

    PubMed

    Ahmed, Mohamed Ahmed Ibrahim; Vogel, Christoph Franz Adam

    2015-05-01

    Studying insecticide resistance in mosquitoes has attracted the attention of many scientists to elucidate the pathways of resistance development and to design novel strategies in order to prevent or minimize the spread and evolution of resistance. Here, we tested the synergistic action of piperonyl butoxide (PBO) and two octopamine receptor (OR) agonists, amitraz (AMZ) and chlordimeform (CDM) on selected novel insecticides to increase their lethal action on the fourth instar larvae of Aedes aegypti L. However, chlorfenapyr was the most toxic insecticide (LC50?=?193, 102, and 48?ng/ml, after 24, 48, and 72?h exposure, respectively) tested. Further, PBO synergized all insecticides and the most toxic combinatorial insecticide was nitenpyram even after 48 and 72?h exposure. In addition, OR agonists significantly synergized most of the selected insecticides especially after 48 and 72?h exposure. The results imply that the synergistic effects of amitraz are a promising approach in increasing the potency of certain insecticides in controlling the dengue vector Ae. aegypti mosquito. PMID:25987220

  17. Scale-up of a programme for malaria vector control using long-lasting insecticide-treated nets: lessons from South Sudan

    PubMed Central

    Remijo, Constantino D; Pasquale, Harriet; Baba, Samson P; Lako, Richard L

    2014-01-01

    Abstract Problem Long-lasting insecticidal nets (LLINs) are important tools in malaria control. South Sudan, like many other endemic countries, has struggled to improve LLIN coverage and utilization. Approach In 2006, Southern Sudan – known as South Sudan after independence in 2011 – initiated a strategic plan to increase LLIN coverage so that at least 60% of households had at least one LLIN each. By 2008, the target coverage was 80% of households and the Global Fund had financed a phased scale-up of LLIN distribution in the region. Local setting South Sudan’s entire population is considered to be at risk of malaria. Poor control of the vectors and the large-scale movements of returnees, internally displaced people and refugees have exacerbated the problem. Relevant changes By 2012, approximately 8.0 million LLINs had been distributed in South Sudan. Between 2006 and 2009, the percentage of households possessing at least one LLIN increased from about 12% to 53% and LLIN utilization rates increased from 5 to 25% among children younger than 5 years and from 5 to 36% among pregnant women. The number of recorded malaria cases increased from 71 948 in 2008 to 1 198 357 in 2012. Lessons learnt In post-conflict settings, a phased programme for the national scale-up of LLIN coverage may not have a substantial impact. A nationwide campaign that is centrally coordinated and based on sound guidelines may offer greater benefits. A strong partnership base and effective channels for the timely and supplementary deployment of LLINs may be essential for universal coverage. PMID:24700997

  18. Anti-mosquito plants as an alternative or incremental method for malaria vector control among rural communities of Bagamoyo District, Tanzania

    PubMed Central

    2014-01-01

    Background Plants represent one of the most accessible resources available for mosquito control by communities in Tanzania. However, no documented statistics exist for their contribution in the management of mosquitoes and other insects except through verbal and some publications. This study aimed at assessing communities’ knowledge, attitudes and practices of using plants as an alternative method for mosquito control among selected communities in a malaria-prone area in Tanzania. Methods Questionnaires were administered to 202 respondents from four villages of Bagamoyo District, Pwani Region, in Tanzania followed by participatory rural appraisal with village health workers. Secondary data collection for plants mentioned by the communities was undertaken using different search engines such as googlescholar, PubMED and NAPRALERT. Results Results showed about 40.3% of respondents used plants to manage insects, including mosquitoes. A broad profile of plants are used, including “mwarobaini” (Azadirachta indica) (22.5%), “mtopetope” (Annona spp) (20.8%), “mchungwa/mlimau” (Citrus spp) (8.3%), “mvumbashi/uvumbati” (Ocimum spp) (7.4%), “mkorosho” (Anacadium occidentale) (7.1%), “mwembe” (5.4%) (Mangifera indica), “mpera” (4.1%) (Psidium spp) and “maganda ya nazi” (4.1%) (Cocos nucifera). Majority of respondents collected these plants from the wild (54.2%), farms (28.9%) and/or home gardens (6%). The roles played by these plants in fighting mosquitoes is reflected by the majority that deploy them with or without bed-nets (p > 0.55) or insecticidal sprays (p >0.22). Most respondents were aware that mosquitoes transmit malaria (90.6%) while few respondents associated elephantiasis/hydrocele (46.5%) and yellow fever (24.3%) with mosquitoes. Most of the ethnobotanical uses mentioned by the communities were consistent with scientific information gathered from the literature, except for Psidium guajava, which is reported for the first time in insect control. Conclusion This survey has indicated some knowledge gap among community members in managing mosquito vectors using plant. The communities need a basic health education and sensitization for effective exploitation of this valuable tool for reducing mosquitoes and associated disease burdens. On the other hand, the government of Tanzania should strengthen advocacy of botanical pesticides development, registration and regulation for public health benefits because they are source of pest control tools people rely on them. PMID:25015092

  19. Rotations with Rodrigues' Vector

    ERIC Educational Resources Information Center

    Pina, E.

    2011-01-01

    The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears…

  20. Eliminating malaria vectors

    PubMed Central

    2013-01-01

    Malaria vectors which predominantly feed indoors upon humans have been locally eliminated from several settings with insecticide treated nets (ITNs), indoor residual spraying or larval source management. Recent dramatic declines of An. gambiae in east Africa with imperfect ITN coverage suggest mosquito populations can rapidly collapse when forced below realistically achievable, non-zero thresholds of density and supporting resource availability. Here we explain why insecticide-based mosquito elimination strategies are feasible, desirable and can be extended to a wider variety of species by expanding the vector control arsenal to cover a broader spectrum of the resources they need to survive. The greatest advantage of eliminating mosquitoes, rather than merely controlling them, is that this precludes local selection for behavioural or physiological resistance traits. The greatest challenges are therefore to achieve high biological coverage of targeted resources rapidly enough to prevent local emergence of resistance and to then continually exclude, monitor for and respond to re-invasion from external populations. PMID:23758937

  1. Assessment of Immune Interference, Antagonism and Diversion following Human Immunization with Bi-Allelic Blood-Stage Malaria Viral Vectored Vaccines and Controlled Malaria Infection

    PubMed Central

    Elias, Sean C.; Collins, Katharine A.; Halstead, Fenella D.; Choudhary, Prateek; Bliss, Carly M.; Ewer, Katie J.; Sheehy, Susanne H.; Duncan, Christopher J. A.; Biswas, Sumi; Hill, Adrian V. S.; Draper, Simon J.

    2012-01-01

    Overcoming antigenic variation is one of the major challenges in the development of an effective vaccine against Plasmodium falciparum, a causative agent of human malaria. Inclusion of multiple antigen variants in subunit vaccine candidates is one strategy that has aimed to overcome this problem for the leading blood-stage malaria vaccine targets, merozoite surface protein 1 (MSP1) and apical membrane antigen 1 (AMA1). However previous studies, utilizing malaria antigens, have concluded that inclusion of multiple allelic variants, encoding altered peptide ligands (APL), in such a vaccine may be detrimental to both the priming and in vivo re-stimulation of antigen-experienced T cells. Here we analyze the T cell responses to two alleles of MSP1 and AMA1 induced by vaccination of malaria-naïve adult volunteers with bi-valent viral vectored vaccine candidates. We show a significant bias to the 3D7/MAD20 allele compared to the Wellcome allele for the 33kDa region of MSP1, but not for the 19kDa fragment or the AMA1 antigen. Whilst this bias could be caused by ‘immune interference’ at priming, the data don’t support a significant role for ‘immune antagonism’ during memory T cell re-stimulation, despite observation of the latter at a minimal epitope level in vitro. A lack of class I HLA epitopes in the Wellcome allele that are recognized by vaccinated volunteers may in fact contribute to the observed bias. We also show that controlled infection with 3D7 strain P. falciparum parasites neither boosts existing 3D7-specific T cell responses nor appears to ‘immune divert’ cellular responses towards the Wellcome allele. PMID:23293353

  2. Low-volume application by mist-blower compared with conventional compression sprayer treatment of houses with residual pyrethroid to control the malaria vector Anopheles albimanus in Mexico.

    PubMed

    Villarreal, C; Rodriguez, M H; Bown, D N; Arredondo-Jiménez, J I

    1995-04-01

    Village-scale trials were carried out in southern Mexico to compare the efficacy of indoor-spraying of the pyrethroid insecticide lambda-cyhalothrin applied either as low-volume (LV) aqueous emulsion or as wettable-powder (WP) aqueous suspension for residual control of the principal coastal malaria vector Anopheles albimanus. Three indoor spray rounds were conducted at 3-month intervals using back-pack mist-blowers to apply lambda-cyhalothrin 12.5 mg a.i./m2 by LV, whereas the WP was applied by conventional compression sprayer at a mean rate of 26.5 mg a.i./m2. Both treatments caused mosquito mortality indoors and outdoors (collected inside house curtains) as a result of contact with treated surfaces before and after feeding, but had no significant impact on overall population density of An. albimanus resting indoors or assessed by human bait collections. Contact bioassays showed that WP and LV treatments with lambda-cyhalothrin were effective for 12-20 weeks (> 75% mortality) without causing excito-repellency. Compared to the WP treatment (8 houses/man/day), LV treatment (25 houses/man/day) was more than 3 times quicker per house, potentially saving 68% of labour costs. This is offset, however, by the much lower unit price of a compression sprayer (e.g. Hudson 'X-pert' at US$120) than a mist-blower (e.g. 'Super Jolly' at US$350), and higher running costs for LV applications. It was calculated, therefore, that LV becomes more economical than WP after 18.8 treatments/100 houses/10 men at equivalent rates of application, or after 7.6 spray rounds with half-rate LV applications. PMID:7787228

  3. Control of plasma waves associated with the space shuttle by the angle between the orbiter's velocity vector and the magnetic field

    SciTech Connect

    Cairns, I.H.; Gurnett, D.A. )

    1991-05-01

    The interaction between water outgassed from the space shuttle and the ionospheric plasma leads to production of water ions by charge exchange and an active and complex plasma wave environment for the space shuttle. The authors show that the amplitude and spectral character of some of these waves are controlled by the angle between the magnetic field and the shuttle's velocity vector V{sub T} relative to the ionospheric plasma. When the flow is approximately perpendicular to the magnetic field (V{sub {parallel}}/V{sub T}{approximately}0), large wave amplitudes and characteristic mushroom wave structures are observed, whereas more nearly parallel flows {vert bar}V{parallel}{vert bar} {approximately} V{sub {perpendicular}} are characterized by low wave levels. They show that linear instability theory predicts the growth of Doppler-shifted lower hybrid waves in the observed frequency range when driven by the ring and/or beam distributions of water ions produced by charge exchange in the vicinity of the space shuttle. Two mutually compatible interpretations for the V{sub {parallel}}/V{sub T} effect exist. The first interpretation involves the path lengths available for growth of waves driven by pickup ions varying with the quantity V{sub {parallel}}/V{sub T} and being limited by spatial variations in the water ion distribution. The second interpretation follows directly from the linear theory: decreasing the ring/beam speed V{sub {perpendicular}} of the pickup ions driving the waves (increasing V{sub {parallel}}/V{sub T} results in smaller growth rates), with zero growth rate below some threshold value of V{sub {perpendicular}}.These results have immediate implications for future shuttle missions and orbiting platforms subject to outgassing of water. If these facilities are used for ionospheric plasma studies or active experiments involving plasma waves, the plasma wave background due to pickup ions associated with the orbiter should be minimized.

  4. Skyrmions with vector mesons revisited

    E-print Network

    Oh, Yongseok

    2014-01-01

    In order to develop a model that can describe both a single baryon and multi-baryon systems on the same footing, we re-investigate the Skyrme model in a chiral Lagrangian derived from the hidden local symmetry (HLS) up to $O(p^4)$ including the homogeneous Wess-Zumino terms. We use the master formulas that connect the parameters of the HLS Lagrangian and a class of holographic QCD models, which provides a controllable way to determine the low-energy constants of the Lagrangian once the pion decay constant and the vector meson mass are given. Therefore, this model allows us to study the role of vector mesons in the skyrmion structure. We find that the $\\rho$ and $\\omega$ vector mesons have different roles in the skyrmion structure and that the $\\omega$ meson has an important role in the properties of the nucleon.

  5. Fiber propagation of vector modes

    E-print Network

    Ndagano, Bienvenu; McLaren, Melanie; Duparre, Michael; Forbes, Andrew

    2015-01-01

    Here we employ both dynamic and geometric phase control of light to produce radially modulated vector-vortex modes, the natural modes of optical fibers. We then measure these modes using a vector modal decomposition set-up as well as a tomography measurement, the latter providing a degree of the non-separability of the vector states, akin to an entanglement measure for quantum states. We demonstrate the versatility of the approach by creating the natural modes of a step-index fiber, which are known to exhibit strong mode coupling, and measure the modal cross-talk and non-separability decay during propagation. Our approach will be useful in mode division multiplexing schemes for transport of classical and quantum states.

  6. The vector ruling protractor

    NASA Technical Reports Server (NTRS)

    Zahm, A F

    1924-01-01

    The theory, structure and working of a vector slide rule is presented in this report. This instrument is used for determining a vector in magnitude and position when given its components and its moment about a point in their plane.

  7. Understanding Singular Vectors

    ERIC Educational Resources Information Center

    James, David; Botteron, Cynthia

    2013-01-01

    matrix yields a surprisingly simple, heuristical approximation to its singular vectors. There are correspondingly good approximations to the singular values. Such rules of thumb provide an intuitive interpretation of the singular vectors that helps explain why the SVD is so…

  8. Multistage vector (MSV) therapeutics.

    PubMed

    Wolfram, Joy; Shen, Haifa; Ferrari, Mauro

    2015-12-10

    One of the greatest challenges in the field of medicine is obtaining controlled distribution of systemically administered therapeutic agents within the body. Indeed, biological barriers such as physical compartmentalization, pressure gradients, and excretion pathways adversely affect localized delivery of drugs to pathological tissue. The diverse nature of these barriers requires the use of multifunctional drug delivery vehicles that can overcome a wide range of sequential obstacles. In this review, we explore the role of multifunctionality in nanomedicine by primarily focusing on multistage vectors (MSVs). The MSV is an example of a promising therapeutic platform that incorporates several components, including a microparticle, nanoparticles, and small molecules. In particular, these components are activated in a sequential manner in order to successively address transport barriers. PMID:26264836

  9. Rhotrix Vector Spaces

    ERIC Educational Resources Information Center

    Aminu, Abdulhadi

    2010-01-01

    By rhotrix we understand an object that lies in some way between (n x n)-dimensional matrices and (2n - 1) x (2n - 1)-dimensional matrices. Representation of vectors in rhotrices is different from the representation of vectors in matrices. A number of vector spaces in matrices and their properties are known. On the other hand, little seems to be…

  10. A Phase I Double Blind, Placebo-Controlled, Randomized Study of a Multigenic HIV-1 Adenovirus Subtype 35 Vector Vaccine in Healthy Uninfected Adults

    PubMed Central

    Hayes, Peter; Gill, Dilbinder; Kopycinski, Jakub; Cheeseman, Hannah; Cashin-Cox, Michelle; Naarding, Marloes; Clark, Lorna; Fernandez, Natalia; Bunce, Catherine A.; Hay, Christine M.; Welsh, Sabrina; Komaroff, Wendy; Hachaambwa, Lottie; Tarragona-Fiol, Tony; Sayeed, Eddy; Zachariah, Devika; Ackland, James; Loughran, Kelley; Barin, Burc; Cormier, Emmanuel; Cox, Josephine H.; Fast, Patricia; Excler, Jean-Louis

    2012-01-01

    Background We conducted a phase I, randomized, double-blind, placebo-controlled trial to assess the safety and immunogenicity of escalating doses of two recombinant replication defective adenovirus serotype 35 (Ad35) vectors containing gag, reverse transcriptase, integrase and nef (Ad35-GRIN) and env (Ad35-ENV), both derived from HIV-1 subtype A isolates. The trial enrolled 56 healthy HIV-uninfected adults. Methods Ad35-GRIN/ENV (Ad35-GRIN and Ad35-ENV mixed in the same vial in equal proportions) or Ad35-GRIN was administered intramuscularly at 0 and 6 months. Participants were randomized to receive either vaccine or placebo (10/4 per group, respectively) within one of four dosage groups: Ad35-GRIN/ENV 2×109 (A), 2×1010 (B), 2×1011 (C), or Ad35-GRIN 1×1010 (D) viral particles. Results No vaccine-related serious adverse event was reported. Reactogenicity events reported were dose-dependent, mostly mild or moderate, some severe in Group C volunteers, all transient and resolving spontaneously. IFN-? ELISPOT responses to any vaccine antigen were detected in 50, 56, 70 and 90% after the first vaccination, and in 75, 100, 88 and 86% of Groups A–D vaccine recipients after the second vaccination, respectively. The median spot forming cells (SFC) per 106 PBMC to any antigen was 78–139 across Groups A–C and 158–174 in Group D, after each of the vaccinations with a maximum of 2991 SFC. Four to five HIV proteins were commonly recognized across all the groups and over multiple timepoints. CD4+ and CD8+ T-cell responses were polyfunctional. Env antibodies were detected in all Group A–C vaccinees and Gag antibodies in most vaccinees after the second immunization. Ad35 neutralizing titers remained low after the second vaccination. Conclusion/Significance Ad35-GRIN/ENV reactogenicity was dose-related. HIV-specific cellular and humoral responses were seen in the majority of volunteers immunized with Ad35-GRIN/ENV or Ad35-GRIN and increased after the second vaccination. T-cell responses were broad and polyfunctional. Trial Registration ClinicalTrials.gov NCT00851383 PMID:22870265

  11. Efficacy of sunlight-activatable porphyrin formulates on larvae of Anopheles gambiae M and S molecular forms and An. arabiensis: a potential novel biolarvicide for integrated malaria vector control.

    PubMed

    Fabris, Clara; Ouédraogo, Robert Kossivi; Coppellotti, Olimpia; Dabiré, Roch K; Diabaté, Abdoulaye; Di Martino, Piera; Guidolin, Laura; Jori, Giulio; Lucantoni, Leonardo; Lupidi, Giulio; Martena, Valentina; Sawadogo, Simon P; Soncin, Marina; Habluetzel, Annette

    2012-09-01

    Biolarvicides, such as microbial formulations based on Bacillus thuringiensis and B. sphaericus, have been found to be highly effective against mosquito larvae and are currently employed as eco-friendly alternatives to synthetic chemical insecticides for vector control. Recently, a porphyrin of natural origin has been suggested as a sunlight-activatable larvicide against the dengue vector Aedes aegypti. In order to validate the approach for the control of the malaria vector, we tested the photo-larvicidal activity of a novel porphyrin, namely meso-tri(N-methyl-pyridyl), mono(N-dodecyl-pyridyl)porphine, C12, associated with two specifically selected carriers, against Anopheles gambiae s.s. and An. arabiensis larvae, both laboratory reared and collected from malaria endemic sites in Burkina Faso. Both C12-porphyrin formulates, when administered to larvae at a 50?M porphyrin dose, were accumulated in the alimentary canal. Subsequent exposure of the porphyrin-loaded larvae to sunlight for short times (0.5-3h) led to a complete mortality. The high efficacy exhibited by a "foodstuff" porphyrin formulate also in the presence of typical larval food particles opens promising perspectives for the development of an effective photocidal larvicide. PMID:22668835

  12. Mapping the magnetic field vector in a fountain clock

    SciTech Connect

    Gertsvolf, Marina; Marmet, Louis

    2011-12-15

    We show how the mapping of the magnetic field vector components can be achieved in a fountain clock by measuring the Larmor transition frequency in atoms that are used as a spatial probe. We control two vector components of the magnetic field and apply audio frequency magnetic pulses to localize and measure the field vector through Zeeman spectroscopy.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 specifi...

  14. Revisit the complexation of PEI and DNA --How to make low cytotoxic and highly efficient PEI gene transfection non-viral vectors with a controllable chain length

    E-print Network

    Wu, Chi

    Revisit the complexation of PEI and DNA -- How to make low cytotoxic and highly efficient PEI gene vector to transfer genes, but its cytotoxicity limits its applications in bio-related research. To solve such an efficiency-versus-cytotoxicity catch-22 problem, the disulfide bond has been previously used to link less

  15. Entomopathogenic fungi as a biological control agents for the vector of the laurel wilt disease, the redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle (RAB), Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae) vectors the fungal pathogen, Raffaelea lauricola, which causes laurel wilt (LW), a lethal disease of trees in the family Lauraceae, including the most commercially important crop in this family, avocado, Pe...

  16. Malaria vectors in the Greater Mekong Subregion: overview of malaria vectors and remaining challenges.

    PubMed

    Hii, Jeffrey; Rueda, Leopoldo M

    2013-01-01

    Malaria transmission in the Greater Mekong Subregion depends on, among other factors, vector behavior and ecology, and the degree of contact between humans and the Anopheles mosquitoes. This chapter will review and update knowledge presented in the 2003 Mekong Malaria monograph for planning and implementing evidence-based vector control programs. Collation of 150 publications and reports showed that the highest number of vector species reported included An. minimus Theobald complex (26.74%), An. dirus Peyton and Harrison (14.26%), An. sundaicus (Rodenwaldt) (5.65%), An. sinensis Wiedemann (4.29%), An. maculatus Theobald (4.23%), An. philippinensis Ludlow (1.62%), An. annularis Van der Wulp (0.37%), An. campestris Reid (0.25%), and An. lesteri Baisas and Hu (=anthropophagus) (0.045%). Other Anopheles species accounted for 44.44%. Anopheles dirus was incriminated as a vector of Plasmodium knowlesi malaria in Viet Nam for the first time, but remained a suspected simian vector in other countries in the region. Well-designed trials of innovative strategies in intractable and difficult situations are needed, including a better understanding of the various causal relations and interactions between physiology, environment, and vector bionomics. While current front-line vector control interventions have contributed significantly to a worldwide decrease of malaria, indoor residual spraying and insecticide-treated bednets/ long lasting insecticidal bednets have had variable impact on exophilic/exophagic and/or early biting vectors. As vectors' responses to control measures vary in different areas, entomological studies on the efficacy of insecticide-treated bednets and other innovative control tools to ensure that strategies are tailored to local circumstances. Given that current tools are insufficient to break transmission cycles, more strategic investments into research on outdoor transmission, monitoring of insecticide resistance, vector species identities, vector mapping, target profiles of new control technologies and delivery systems are required. PMID:24159831

  17. Covariantised Vector Galileons

    E-print Network

    Hull, Matthew; Tasinato, Gianmassimo

    2015-01-01

    Vector galileons are ghost-free systems containing higher derivative interactions of vector fields. They break the vector gauge symmetry, and the dynamics of the longitudinal vector polarizations acquire a Galileon symmetry in an appropriate decoupling limit in Minkowski space. Using an ADM approach, we carefully reconsider the coupling with gravity of vector galileons, with the aim of studying the necessary conditions to avoid the propagation of ghosts. We develop arguments that put on a more solid footing the results previously obtained in the literature. Moreover, working in analogy with the scalar counterpart, we find indications for the existence of a `beyond Horndeski' theory involving vector degrees of freedom, that avoids the propagation of ghosts thanks to secondary constraints. In addition, we analyse a Higgs mechanism for generating vector galileons through spontaneous symmetry breaking, and we present its consistent covariantisation.

  18. In vivo imaging of trypanosome-brain interactions and development of a rapid screening test for drugs against CNS stage trypanosomiasis.

    PubMed

    Myburgh, Elmarie; Coles, Jonathan A; Ritchie, Ryan; Kennedy, Peter G E; McLatchie, Alex P; Rodgers, Jean; Taylor, Martin C; Barrett, Michael P; Brewer, James M; Mottram, Jeremy C

    2013-01-01

    HUMAN AFRICAN TRYPANOSOMIASIS (HAT) MANIFESTS IN TWO STAGES OF DISEASE: firstly, haemolymphatic, and secondly, an encephalitic phase involving the central nervous system (CNS). New drugs to treat the second-stage disease are urgently needed, yet testing of novel drug candidates is a slow process because the established animal model relies on detecting parasitemia in the blood as late as 180 days after treatment. To expedite compound screening, we have modified the GVR35 strain of Trypanosoma brucei brucei to express luciferase, and have monitored parasite distribution in infected mice following treatment with trypanocidal compounds using serial, non-invasive, bioluminescence imaging. Parasites were detected in the brains of infected mice following treatment with diminazene, a drug which cures stage 1 but not stage 2 disease. Intravital multi-photon microscopy revealed that trypanosomes enter the brain meninges as early as day 5 post-infection but can be killed by diminazene, whereas those that cross the blood-brain barrier and enter the parenchyma by day 21 survived treatment and later caused bloodstream recrudescence. In contrast, all bioluminescent parasites were permanently eliminated by treatment with melarsoprol and DB829, compounds known to cure stage 2 disease. We show that this use of imaging reduces by two thirds the time taken to assess drug efficacy and provides a dual-modal imaging platform for monitoring trypanosome infection in different areas of the brain. PMID:23991236

  19. Feasibility of a combined camp approach for vector control together with active case detection of visceral leishmaniasis, post kala-azar dermal leishmaniasis, tuberculosis, leprosy and malaria in Bangladesh, India and Nepal: an exploratory study

    PubMed Central

    Banjara, Megha R.; Kroeger, Axel; Huda, Mamun M.; Kumar, Vijay; Gurung, Chitra K.; Das, Murari L.; Rijal, Suman; Das, Pradeep; Mondal, Dinesh

    2015-01-01

    Background We assessed the feasibility and results of active case detection (ACD) of visceral leishmaniasis (VL), post kala-azar dermal leishmaniasis (PKDL) and other febrile diseases as well as of bednet impregnation for vector control. Methods Fever camps were organized and analyzed in twelve VL endemic villages in Bangladesh, India, and Nepal. VL, PKDL, tuberculosis, malaria and leprosy were screened among the febrile patients attending the camps, and existing bednets were impregnated with a slow release insecticide. Results Among the camp attendees one new VL case and two PKDL cases were detected in Bangladesh and one VL case in Nepal. Among suspected tuberculosis cases two were positive in India but none in the other countries. In India, two leprosy cases were found. No malaria cases were detected. Bednet impregnation coverage during fever camps was more than 80% in the three countries. Bednet impregnation led to a reduction of sandfly densities after 2 weeks by 86% and 32%, and after 4 weeks by 95% and 12% in India and Nepal respectively. The additional costs for the control programmes seem to be reasonable. Conclusion It is feasible to combine ACD camps for VL and PKDL along with other febrile diseases, and vector control with bednet impregnation. PMID:25918216

  20. Eco-friendly control of malaria and arbovirus vectors using the mosquitofish Gambusia affinis and ultra-low dosages of Mimusops elengi-synthesized silver nanoparticles: towards an integrative approach?

    PubMed

    Subramaniam, Jayapal; Murugan, Kadarkarai; Panneerselvam, Chellasamy; Kovendan, Kalimuthu; Madhiyazhagan, Pari; Kumar, Palanisamy Mahesh; Dinesh, Devakumar; Chandramohan, Balamurugan; Suresh, Udaiyan; Nicoletti, Marcello; Higuchi, Akon; Hwang, Jiang-Shiou; Kumar, Suresh; Alarfaj, Abdullah A; Munusamy, Murugan A; Messing, Russell H; Benelli, Giovanni

    2015-12-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. However, the use of synthetic insecticides to control Culicidae may lead to high operational costs and adverse non-target effects. Plant-borne compounds have been proposed for rapid extracellular synthesis of mosquitocidal nanoparticles. Their impact against biological control agents of mosquito larval populations has been poorly studied. We synthesized silver nanoparticles (AgNP) using the aqueous leaf extract of Mimusops elengi as a reducing and stabilizing agent. The formation of AgNP was studied using different biophysical methods, including UV-vis spectrophotometry, TEM, XRD, EDX and FTIR. Low doses of AgNP showed larvicidal and pupicidal toxicity against the malaria vector Anopheles stephensi and the arbovirus vector Aedes albopictus. AgNP LC50 against A. stephensi ranged from 12.53 (I instar larvae) to 23.55 ppm (pupae); LC50 against A. albopictus ranged from 11.72 ppm (I) to 21.46 ppm (pupae). In the field, the application of M. elengi extract and AgNP (10?×?LC50) led to 100 % larval reduction after 72 h. In adulticidal experiments, AgNP showed LC50 of 13.7 ppm for A. stephensi and 14.7 ppm for A. albopictus. The predation efficiency of Gambusia affinis against A. stephensi and A. albopictus III instar larvae was 86.2 and 81.7 %, respectively. In AgNP-contaminated environments, predation was 93.7 and 88.6 %, respectively. This research demonstrates that M. elengi-synthesized AgNP may be employed at ultra-low doses to reduce larval populations of malaria and arbovirus vectors, without detrimental effects on predation rates of mosquito natural enemies, such as larvivorous fishes. PMID:26300364

  1. Vector Relations Michael Kaneshige

    E-print Network

    Rodriguez, Carlos

    Vector Relations Michael Kaneshige January 14, 1995 1 Vector Calculus in Cartesian Coordinates ~ r = â?? i @ @x + â?? j @ @y + â?? k @ @z Gradient : ~ r\\Phi = @ \\Phi @x â?? i + @ \\Phi @y â?? j + @ \\Phi @z â?? k Divergence : ~ r \\Delta ~ A = @A 1 @x + @A 2 @y + @A 3 @z Curl : ~ r \\Theta ~ A = ( @A 3 @y \\Gamma @A 2 @z

  2. Hunting the Vector Hybrid

    E-print Network

    A Donnachie; Yu S Kalashnikova

    1999-02-01

    The current state of analysis of e+e- annihilation below 2.0 GeV and of the vector component of tau decay is reviewed. The evidence for and against the presence of hybrid vectors is discussed. It is concluded that the data strongly favour their inclusion, and the consequences of this are outlined.

  3. Vector generator scan converter

    DOEpatents

    Moore, James M. (Livermore, CA); Leighton, James F. (Livermore, CA)

    1990-01-01

    High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O (input/output) channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardward for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold.

  4. Vector generator scan converter

    DOEpatents

    Moore, J.M.; Leighton, J.F.

    1988-02-05

    High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardware for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold. 7 figs.

  5. Viral Vector Production: Adenovirus.

    PubMed

    Kim, Julius W; Morshed, Ramin A; Kane, J Robert; Auffinger, Brenda; Qiao, Jian; Lesniak, Maciej S

    2016-01-01

    Adenoviral vectors have proven to be valuable resources in the development of novel therapies aimed at targeting pathological conditions of the central nervous system, including Alzheimer's disease and neoplastic brain lesions. Not only can some genetically engineered adenoviral vectors achieve remarkably efficient and specific gene delivery to target cells, but they also may act as anticancer agents by selectively replicating within cancer cells.Due to the great interest in using adenoviral vectors for various purposes, the need for a comprehensive protocol for viral vector production is especially apparent. Here, we describe the process of generating an adenoviral vector in its entirety, including the more complex process of adenoviral fiber modification to restrict viral tropism in order to achieve more efficient and specific gene delivery. PMID:26611583

  6. Line Integral of a Vector.

    ERIC Educational Resources Information Center

    Balabanian, Norman

    This programed booklet is designed for the engineering student who understands and can use vector and unit vector notation, components of a vector, parallel law of vector addition, and the dot product of two vectors. Content begins with work done by a force in moving a body a certain distance along some path. For each of the examples and problem…

  7. Evaluation of attractive toxic sugar bait (ATSB)-Barrier for control of vector and nuisance mosquitoes and its effect on non-target organisms in sub-tropical environments in Florida.

    PubMed

    Qualls, Whitney A; Müller, Günter C; Revay, Edita E; Allan, Sandra A; Arheart, Kristopher L; Beier, John C; Smith, Michal L; Scott, Jodi M; Kravchenko, Vasiliy D; Hausmann, Axel; Yefremova, Zoya A; Xue, Rui-De

    2014-03-01

    The efficacy of attractive toxic sugar baits (ATSB) with the active ingredient eugenol, an Environmental Protection Agency exempt compound, was evaluated against vector and nuisance mosquitoes in both laboratory and field studies. In the laboratory, eugenol combined in attractive sugar bait (ASB) solution provided high levels of mortality for Aedes aegypti, Culex quinquefasciatus, and Anopheles quadrimaculatus. Field studies demonstrated significant control: >70% reduction for Aedes atlanticus, Aedes. infirmatus, and Culex nigripalpus and >50% reduction for Anopheles crucians, Uranotaenia sapphirina, Culiseta melanura, and Culex erraticus three weeks post ATSB application. Furthermore, non-target feeding of six insect orders, Hymenoptera, Lepidoptera, Coleoptera, Diptera, Hemiptera, and Orthoptera, was evaluated in the field after application of a dyed-ASB to flowering and non-flowering vegetation. ASB feeding (staining) was determined by dissecting the guts and searching for food dye with a dissecting microscope. The potential impact of ATSB on non-targets, applied on green non-flowering vegetation was low for all non-target groups (0.9%). However, application of the ASB to flowering vegetation resulted in significant staining of the non-target insect orders. This highlights the need for application guidelines to reduce non-target effects. No mortality was observed in laboratory studies with predatory non-targets, spiders, praying mantis, or ground beetles, after feeding for three days on mosquitoes engorged on ATSB. Overall, our laboratory and field studies support the use of eugenol as an active ingredient for controlling important vector and nuisance mosquitoes when used as an ATSB toxin. This is the first study demonstrating effective control of anophelines in non-arid environments which suggest that even in highly competitive sugar rich environments this method could be used for control of malaria in Latin American countries. PMID:24361724

  8. Evaluation of attractive toxic sugar bait (ATSB)—barrier for control of vector and nuisance mosquitoes and its effect on non-target organisms in sub-tropical environments in Florida

    PubMed Central

    Qualls, Whitney A.; Müller, Günter C.; Revay, Edita E.; Allan, Sandra A.; Arheart, Kristopher L.; Beier, John C.; Smith, Michal L.; Scott, Jodi M.; Kravchenko, Vasiliy D.; Hausmann, Axel; Yefremova, Zoya A.; Xue, Rui-De

    2014-01-01

    The efficacy of attractive toxic sugar baits (ATSB) with the active ingredient eugenol, an Environmental Protection Agency exempt compound, was evaluated against vector and nuisance mosquitoes in both laboratory and field studies. In the laboratory, eugenol combined in attractive sugar bait (ASB) solution provided high levels of mortality for Aedes aegypti, Culex quinquefasciatus, and Anopheles quadrimaculatus. Field studies demonstrated significant control: > 70% reduction for Aedes atlanticus, Ae. infirmatus, and Culex nigripalpus and > 50% reduction for An. crucians, Uranotaenia sapphirina, Culiseta melanura, and Cx. erraticus three weeks post ATSB application. Furthermore, non-target feeding of six insect orders, Hymenoptera, Lepidoptera, Coleoptera, Diptera, Hemiptera, and Orthoptera, was evaluated in the field after application of a dyed-ASB to flowering and non-flowering vegetation. ASB feeding (staining) was determined by dissecting the guts and searching for food dye with a dissecting microscope. The potential impact of ATSB on non-targets, applied on green non-flowering vegetation was low for all non-target groups (0.9%). However, application of the ASB to flowering vegetation resulted in significant staining of the non-target insect orders. This highlights the need for application guidelines to reduce non-target effects. No mortality was observed in laboratory studies with predatory non-targets, spiders, praying mantis, or ground beetles, after feeding for three days on mosquitoes engorged on ATSB. Overall, our laboratory and field studies support the use of eugenol as an active ingredient for controlling important vector and nuisance mosquitoes when used as an ATSB toxin. This is the first study demonstrating effective control of anophelines in non-arid environments which suggest that even in highly competitive sugar rich environments this method could be used for control of malaria in Latin American countries. PMID:24361724

  9. Kenyan purple tea anthocyanins and coenzyme-Q10 ameliorate post treatment reactive encephalopathy associated with cerebral human African trypanosomiasis in murine model.

    PubMed

    Rashid, Khalid; Wachira, Francis N; Nyariki, James N; Isaac, Alfred O

    2014-04-01

    Human African trypanosomiasis (HAT) is a tropical disease caused by two subspecies of Trypanosoma brucei, the East African variant T. b. rhodesiense and the West African variant T. b. gambiense. Melarsoprol, an organic arsenical, is the only drug used to treat late stage T. b. rhodesiense infection. Unfortunately, this drug induces an extremely severe post treatment reactive encephalopathy (PTRE) in up to 10% of treated patients, half of whom die from this complication. A highly reproducible mouse model was adapted to assess the use of Kenyan purple tea anthocyanins and/or coenzyme-Q10 in blocking the occurrence of PTRE. Female Swiss white mice were inoculated intraperitoneally with approximately 10(4) trypanosome isolate T. b. rhodesiense KETRI 2537 and treated sub-curatively 21days post infection with 5mg/kg diminazene aceturate (DA) daily for 3days to induce severe late CNS infection that closely mirrors PTRE in human subjects. Thereafter mice were monitored for relapse of parasitemia after which they were treated with melarsoprol at a dosage of 3.6mg/kg body weight for 4days and sacrificed 24h post the last dosage to obtain brain samples. Brain sections from mice with PTRE that did not receive any antioxidant treatment showed a more marked presence of inflammatory cells, microglial activation and disruption of the brain parenchyma when compared to PTRE mice supplemented with either coenzyme-Q10, purple tea anthocyanins or a combination of the two. The mice group that was treated with coenzyme-Q10 or purple tea anthocyanins had higher levels of GSH and aconitase-1 in the brain compared to untreated groups, implying a boost in brain antioxidant capacity. Overall, coenzyme-Q10 treatment produced more beneficial effects compared to anthocyanin treatment. These findings demonstrate that therapeutic intervention with coenzyme-Q10 and/or purple tea anthocyanins can be used in an experimental mouse model to ameliorate PTRE associated with cerebral HAT. PMID:24440762

  10. Application of a resazurin-based high-throughput screening assay for the identification and progression of new treatments for human African trypanosomiasis

    PubMed Central

    Bowling, Tana; Mercer, Luke; Don, Robert; Jacobs, Robert; Nare, Bakela

    2012-01-01

    Human African trypanosomiasis (HAT) is caused by the protozoan parasite Trypanosoma brucei, and the disease is fatal if untreated. There is an urgent need to develop new, safe and effective treatments for HAT because current drugs have extremely poor safety profiles and are difficult to administer. Here we report the development and application of a cell-based resazurin reduction assay for high throughput screening and identification of new inhibitors of T. b. brucei as starting points for the development of new treatments for human HAT. Active compounds identified in primary screening of ?48,000 compounds representing ?25 chemical classes were titrated to obtain IC50 values. Cytotoxicity against a mammalian cell line was determined to provide indications of parasite versus host cell selectivity. Examples from hit series that showed selectivity and evidence of preliminary SAR were re-synthesized to confirm trypanocidal activity prior to initiating hit-to-lead expansion efforts. Additional assays such as serum shift, time to kill and reversibility of compound effect were developed and applied to provide further criteria for advancing compounds through the hit-to-lead phase of the project. From this initial effort, six distinct chemical series were selected and hit-to-lead chemistry was initiated to synthesize several key analogs for evaluation of trypanocidal activity in the resazurin-reduction assay for parasite viability. From the hit-to-lead efforts, a series was identified that demonstrated efficacy in a mouse model for T. b. brucei infection and was progressed into the lead optimization stage. In summary, the present study demonstrates the successful and effective use of resazurin-reduction based assays as tools for primary and secondary screening of a new compound series to identify leads for the treatment of HAT. PMID:24533287

  11. Pharmacology of DB844, an Orally Active aza Analogue of Pafuramidine, in a Monkey Model of Second Stage Human African Trypanosomiasis

    PubMed Central

    Thuita, John K.; Wang, Michael Z.; Kagira, John M.; Denton, Cathrine L.; Paine, Mary F.; Mdachi, Raymond E.; Murilla, Grace A.; Ching, Shelley; Boykin, David W.; Tidwell, Richard R.; Hall, James E.; Brun, Reto

    2012-01-01

    Novel drugs to treat human African trypanosomiasis (HAT) are still urgently needed despite the recent addition of nifurtimox-eflornithine combination therapy (NECT) to WHO Model Lists of Essential Medicines against second stage HAT, where parasites have invaded the central nervous system (CNS). The pharmacology of a potential orally available lead compound, N-methoxy-6-{5-[4-(N-methoxyamidino) phenyl]-furan-2-yl}-nicotinamidine (DB844), was evaluated in a vervet monkey model of second stage HAT, following promising results in mice. DB844 was administered orally to vervet monkeys, beginning 28 days post infection (DPI) with Trypanosoma brucei rhodesiense KETRI 2537. DB844 was absorbed and converted to the active metabolite 6-[5-(4-phenylamidinophenyl)-furanyl-2-yl]-nicotinamide (DB820), exhibiting plasma Cmax values of 430 and 190 nM for DB844 and DB820, respectively, after the 14th dose at 6 mg/kg qd. A 100-fold reduction in blood trypanosome counts was observed within 24 h of the third dose and, at the end of treatment evaluation performed four days post the last drug dose, trypanosomes were not detected in the blood or cerebrospinal fluid of any monkey. However, some animals relapsed during the 300 days of post treatment monitoring, resulting in a cure rate of 3/8 (37.5%) and 3/7 (42.9%) for the 5 mg/kg×10 days and the 6 mg/kg×14 days dose regimens respectively. These DB844 efficacy data were an improvement compared with pentamidine and pafuramidine both of which were previously shown to be non-curative in this model of CNS stage HAT. These data show that synthesis of novel diamidines with improved activity against CNS-stage HAT was possible. PMID:22848769

  12. Polysomnography as a diagnosis and post-treatment follow-up tool in human African trypanosomiasis: a case study in an infant.

    PubMed

    Mpandzou, Ghislain; Cespuglio, Raymond; Ngampo, Stéphane; Bandzouzi, Bébène; Bouteille, Bernard; Vincendeau, Philippe; Buguet, Alain

    2011-06-15

    Gambian (Trypanosoma brucei gambiense) human African trypanosomiasis (HAT) evolves from the hemolymphatic stage 1, treated with pentamidine, to the meningoencephalitic stage 2, often treated with melarsoprol. This arseniate may provoke a deadly reactive encephalopathy. It is therefore crucial to diagnose precisely the stages of HAT, especially when clinical and biological examinations are doubtful. We present here the case of a 30-month old girl (E20 KOLNG) diagnosed with stage 1 HAT during a field survey in June 2007 in Congo. She was followed-up every six months for 18 months in a village dispensary facility at Mpouya. Her health status deteriorated in December 2008, although cerebrospinal fluid (CSF) white blood cell (WBC) count was normal. The child was hospitalized at Brazzaville and a daytime polysomnographic recording (electroencephalogram, electrooculogram, and electromyogram) was performed (Temec Vitaport 3® portable recorder) to avoid a new lumbar puncture. The child presented a complete polysomnographic syndrome of HAT with a major disturbance of the distribution of sleep and wake episodes and the occurrence of sleep onset REM periods (SOREMPs). The relapse at stage 2 was confirmed by a new CSF examination that showed an elevated WBC count (23cells·?L(-1)) with the presence of B lymphocytes. Melarsoprol treatment was undertaken. A post-treatment recording was immediately performed, showing the resolution of sleepwake pattern abnormalities. Another polysomnography, taken four months later, confirmed the normalization of sleep-wake patterns indicating healing. We therefore propose that polysomnography, being a non-invasive technique, should be used in children to alleviate burden caused by HAT staging procedures, especially regarding lumbar punctures in remote African villages. PMID:21470639

  13. Thrust vectoring for lateral-directional stability

    NASA Technical Reports Server (NTRS)

    Peron, Lee R.; Carpenter, Thomas

    1992-01-01

    The advantages and disadvantages of using thrust vectoring for lateral-directional control and the effects of reducing the tail size of a single-engine aircraft were investigated. The aerodynamic characteristics of the F-16 aircraft were generated by using the Aerodynamic Preliminary Analysis System II panel code. The resulting lateral-directional linear perturbation analysis of a modified F-16 aircraft with various tail sizes and yaw vectoring was performed at several speeds and altitudes to determine the stability and control trends for the aircraft compared to these trends for a baseline aircraft. A study of the paddle-type turning vane thrust vectoring control system as used on the National Aeronautics and Space Administration F/A-18 High Alpha Research Vehicle is also presented.

  14. A C. trachomatis Cloning Vector and the Generation of C. trachomatis Strains Expressing Fluorescent Proteins under the Control of a C. trachomatis Promoter

    PubMed Central

    Agaisse, Hervé; Derré, Isabelle

    2013-01-01

    Here we describe a versatile cloning vector for conducting genetic experiments in C. trachomatis. We successfully expressed various fluorescent proteins (i.e. GFP, mCherry and CFP) from C. trachomatis regulatory elements (i.e. the promoter and terminator of the incDEFG operon) and showed that the transformed strains produced wild type amounts of infectious particles and recapitulated major features of the C. trachomatis developmental cycle. C. trachomatis strains expressing fluorescent proteins are valuable tools for studying the C. trachomatis developmental cycle. For instance, we show the feasibility of investigating the dynamics of inclusion fusion and interaction with host proteins and organelles by time-lapse video microscopy. PMID:23441233

  15. The Importance of Vector Management for Prevention of Hospital Infections.

    PubMed

    Çetin, Hüseyin

    2015-09-01

    Many researches show that cockroaches, ants, some other arthropods and also rodents in hospitals, can act as potential vectors of medically important bacteria, fungi and parasites. The results of microbiological studies show that these animals play a significant role in the epidemiology of hospital infections. These vectors may be found inside of the kitchens, patient rooms, toilets, medicine stores, canteen and wards in health care environments. The importance of vector control in order to prevent the spread of nosocomial infections in healthcare facilities was discussed in this paper. This study also gives information on integrated control methods for vectors in hospitals. PMID:26470931

  16. Light Vector Mesons

    E-print Network

    Alexander Milov

    2008-12-21

    This article reviews the current status of experimental results obtained in the measurement of light vector mesons produced in proton-proton and heavy ion collisions at different energies. The review is focused on two phenomena related to the light vector mesons; the modification of the spectral shape in search of Chiral symmetry restoration and suppression of the meson production in heavy ion collisions. The experimental results show that the spectral shape of light vector mesons are modified compared to the parameters measured in vacuum. The nature and the magnitude of the modification depends on the energy density of the media in which they are produced. The suppression patterns of light vector mesons are different from the measurements of other mesons and baryons. The mechanisms responsible for the suppression of the mesons are not yet understood. Systematic comparison of existing experimental results points to the missing data which may help to resolve the problem.

  17. Uniformly elliptically-polarized vector optical fields

    NASA Astrophysics Data System (ADS)

    Pan, Yue; Ren, Zhi-Cheng; Qian, Sheng-Xia; Gao, Xu-Zhen; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2015-03-01

    We present a modified, more universal scheme for generating vector fields. Here we design in principle and experimentally generate a new kind of uniformly elliptically polarized vector field, which has the same ellipticity and sense of local elliptic polarization at any location and also has a flexibly designable distribution of orientation of the elliptic polarization. An introduced additional degree of freedom is used to flexibly change the ellipticity. In particular, the ellipticity and the orientation of polarization can be independently controlled by two parameters. This makes it easier to both control the spatial structure of the polarization and to engineer the focusing field.

  18. Poynting-vector filter

    DOEpatents

    Carrigan, Charles R. (Tracy, CA)

    2011-08-02

    A determination is made of frequency components associated with a particular bearing or location resulting from sources emitting electromagnetic-wave energy for which a Poynting-Vector can be defined. The broadband frequency components associated with a specific direction or location of interest are isolated from other components in the power spectrum that are not associated with the direction or location of interest. The collection of pointing vectors can be used to characterize the source.

  19. Genetics of Mosquito Vector Competence

    PubMed Central

    Beerntsen, Brenda T.; James, Anthony A.; Christensen, Bruce M.

    2000-01-01

    Mosquito-borne diseases are responsible for significant human morbidity and mortality throughout the world. Efforts to control mosquito-borne diseases have been impeded, in part, by the development of drug-resistant parasites, insecticide-resistant mosquitoes, and environmental concerns over the application of insecticides. Therefore, there is a need to develop novel disease control strategies that can complement or replace existing control methods. One such strategy is to generate pathogen-resistant mosquitoes from those that are susceptible. To this end, efforts have focused on isolating and characterizing genes that influence mosquito vector competence. It has been known for over 70 years that there is a genetic basis for the susceptibility of mosquitoes to parasites, but until the advent of powerful molecular biological tools and protocols, it was difficult to assess the interactions of pathogens with their host tissues within the mosquito at a molecular level. Moreover, it has been only recently that the molecular mechanisms responsible for pathogen destruction, such as melanotic encapsulation and immune peptide production, have been investigated. The molecular characterization of genes that influence vector competence is becoming routine, and with the development of the Sindbis virus transducing system, potential antipathogen genes now can be introduced into the mosquito and their effect on parasite development can be assessed in vivo. With the recent successes in the field of mosquito germ line transformation, it seems likely that the generation of a pathogen-resistant mosquito population from a susceptible population soon will become a reality. PMID:10704476

  20. [Prevalence of American trypanosomiasis, syphilis, toxoplasmosis, rubella, hepatitis B, hepatitis C, human immunodeficiency virus infection, assayed through serological tests among pregnant patients, from 1996 to 1998, at the Regional University Hospital Norte do Paraná].

    PubMed

    Reiche, E M; Morimoto, H K; Farias, G N; Hisatsugu, K R; Geller, L; Gomes, A C; Inoue, H Y; Rodrigues, G; Matsuo, T

    2000-01-01

    In order to evaluate the seroprevalence of the american trypanosomiasis, syphilis, toxoplasmosis, rubella, hepatitis B infection, hepatitis C infection and human immunodeficiency virus infection among pregnant women attended at the Hospital Universitário Regional Norte do Paraná, Londrina State University, Paraná, a retrospective study of the serologic results performed in the prenatal routine during the period of June 1996 to June 1998 was carried out. The rates of seropositivity were as follows: american trypanosomiasis = 0.9%, syphilis = 1.6%, toxoplasmosis = 67% (IgG) and 1.8% (IgM), rubella = 89% (IgG) and 1.2% (IgM), hepatitis B surface antigen = 0.8%, hepatitis C virus = 0.8% and human immunodeficiency virus infection = 0.6%. An association between the increase in the seroprevalence of Chagas' disease and patient age was detected (p=0.006). The results underscore the importance of the serological tests in perinatal care, to prevent both the congenital and perinatally transmitted forms of theses infectious diseases. PMID:11175581

  1. The Application of Auto-Disturbance Rejection Control Optimized by Least Squares Support Vector Machines Method and Time-Frequency Representation in Voltage Source Converter-High Voltage Direct Current System

    PubMed Central

    Gao, Zhong-Ke

    2015-01-01

    In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane. PMID:26098556

  2. Ontology for vector surveillance and management.

    PubMed

    Lozano-Fuentes, Saul; Bandyopadhyay, Aritra; Cowell, Lindsay G; Goldfain, Albert; Eisen, Lars

    2013-01-01

    Ontologies, which are made up by standardized and defined controlled vocabulary terms and their interrelationships, are comprehensive and readily searchable repositories for knowledge in a given domain. The Open Biomedical Ontologies (OBO) Foundry was initiated in 2001 with the aims of becoming an "umbrella" for life-science ontologies and promoting the use of ontology development best practices. A software application (OBO-Edit; *.obo file format) was developed to facilitate ontology development and editing. The OBO Foundry now comprises over 100 ontologies and candidate ontologies, including the NCBI organismal classification ontology (NCBITaxon), the Mosquito Insecticide Resistance Ontology (MIRO), the Infectious Disease Ontology (IDO), the IDOMAL malaria ontology, and ontologies for mosquito gross anatomy and tick gross anatomy. We previously developed a disease data management system for dengue and malaria control programs, which incorporated a set of information trees built upon ontological principles, including a "term tree" to promote the use of standardized terms. In the course of doing so, we realized that there were substantial gaps in existing ontologies with regards to concepts, processes, and, especially, physical entities (e.g., vector species, pathogen species, and vector surveillance and management equipment) in the domain of surveillance and management of vectors and vector-borne pathogens. We therefore produced an ontology for vector surveillance and management, focusing on arthropod vectors and vector-borne pathogens with relevance to humans or domestic animals, and with special emphasis on content to support operational activities through inclusion in databases, data management systems, or decision support systems. The Vector Surveillance and Management Ontology (VSMO) includes >2,200 unique terms, of which the vast majority (>80%) were newly generated during the development of this ontology. One core feature of the VSMO is the linkage, through the has vector relation, of arthropod species to the pathogenic microorganisms for which they serve as biological vectors. We also recognized and addressed a potential roadblock for use of the VSMO by the vector-borne disease community: the difficulty in extracting information from OBO-Edit ontology files (*.obo files) and exporting the information to other file formats. A novel ontology explorer tool was developed to facilitate extraction and export of information from the VSMO*.obo file into lists of terms and their associated unique IDs in *.txt or *.csv file formats. These lists can then be imported into a database or data management system for use as select lists with predefined terms. This is an important step to ensure that the knowledge contained in our ontology can be put into practical use. PMID:23427646

  3. Integrated vector management: a critical strategy for combating vector-borne diseases in South Sudan

    PubMed Central

    2013-01-01

    Background Integrated vector management (IVM) based vector control is encouraged by the World Health Organization (WHO). However, operational experience with the IVM strategy has mostly come from countries with relatively well-established health systems and with malaria control focused programmes. Little is known about deployment of IVM for combating multiple vector-borne diseases in post-emergency settings, where delivery structures are less developed or absent. This manuscript reports on the feasibility of operational IVM for combating vector-borne diseases in South Sudan. Case description A methodical review of published and unpublished documents on vector-borne diseases for South Sudan was conducted via systematic literature search of online electronic databases, Google Scholar, PubMed and WHO, using a combination of search terms. Additional, non-peer reviewed literature was examined for information related to the subject. Discussion South Sudan is among the heartlands of vector-borne diseases in the world, characterized by enormous infrastructure, human and financial resource constraints and a weak health system against an increasing number of refugees, returnees and internally displaced people. The presence of a multiplicity of vector-borne diseases in this post-conflict situation presents a unique opportunity to explore the potential of a rational IVM strategy for multiple disease control and optimize limited resource utilization, while maximizing the benefits and providing a model for countries in a similar situation. Conclusion The potential of integrating vector-borne disease control is enormous in South Sudan. However, strengthened coordination, intersectoral collaboration and institutional and technical capacity for entomological monitoring and evaluation, including enforcement of appropriate legislation are crucial. PMID:24156749

  4. Evaluation of the Efficacy of ChAd63-MVA Vectored Vaccines Expressing Circumsporozoite Protein and ME-TRAP Against Controlled Human Malaria Infection in Malaria-Naive Individuals

    PubMed Central

    Hodgson, Susanne H.; Ewer, Katie J.; Bliss, Carly M.; Edwards, Nick J.; Rampling, Thomas; Anagnostou, Nicholas A.; de Barra, Eoghan; Havelock, Tom; Bowyer, Georgina; Poulton, Ian D.; de Cassan, Simone; Longley, Rhea; Illingworth, Joseph J.; Douglas, Alexander D.; Mange, Pooja B.; Collins, Katharine A.; Roberts, Rachel; Gerry, Stephen; Berrie, Eleanor; Moyle, Sarah; Colloca, Stefano; Cortese, Riccardo; Sinden, Robert E.; Gilbert, Sarah C.; Bejon, Philip; Lawrie, Alison M.; Nicosia, Alfredo; Faust, Saul N.; Hill, Adrian V. S.

    2015-01-01

    Background.?Circumsporozoite protein (CS) is the antigenic target for RTS,S, the most advanced malaria vaccine to date. Heterologous prime-boost with the viral vectors simian adenovirus 63 (ChAd63)-modified vaccinia virus Ankara (MVA) is the most potent inducer of T-cells in humans, demonstrating significant efficacy when expressing the preerythrocytic antigen insert multiple epitope–thrombospondin-related adhesion protein (ME-TRAP). We hypothesized that ChAd63-MVA containing CS may result in a significant clinical protective efficacy. Methods.?We conducted an open-label, 2-site, partially randomized Plasmodium falciparum sporozoite controlled human malaria infection (CHMI) study to compare the clinical efficacy of ChAd63-MVA CS with ChAd63-MVA ME-TRAP. Results.?One of 15 vaccinees (7%) receiving ChAd63-MVA CS and 2 of 15 (13%) receiving ChAd63-MVA ME-TRAP achieved sterile protection after CHMI. Three of 15 vaccinees (20%) receiving ChAd63-MVA CS and 5 of 15 (33%) receiving ChAd63-MVA ME-TRAP demonstrated a delay in time to treatment, compared with unvaccinated controls. In quantitative polymerase chain reaction analyses, ChAd63-MVA CS was estimated to reduce the liver parasite burden by 69%–79%, compared with 79%–84% for ChAd63-MVA ME-TRAP. Conclusions.?ChAd63-MVA CS does reduce the liver parasite burden, but ChAd63-MVA ME-TRAP remains the most promising antigenic insert for a vectored liver-stage vaccine. Detailed analyses of parasite kinetics may allow detection of smaller but biologically important differences in vaccine efficacy that can influence future vaccine development. Clinical Trials Registration.?NCT01623557. PMID:25336730

  5. Scalable motion vector coding

    NASA Astrophysics Data System (ADS)

    Barbarien, Joeri; Munteanu, Adrian; Verdicchio, Fabio; Andreopoulos, Yiannis; Cornelis, Jan P.; Schelkens, Peter

    2004-11-01

    Modern video coding applications require transmission of video data over variable-bandwidth channels to a variety of terminals with different screen resolutions and available computational power. Scalable video coding is needed to optimally support these applications. Recently proposed wavelet-based video codecs employing spatial domain motion compensated temporal filtering (SDMCTF) provide quality, resolution and frame-rate scalability while delivering compression performance comparable to that of the state-of-the-art non-scalable H.264-codec. These codecs require scalable coding of the motion vectors in order to support a large range of bit-rates with optimal compression efficiency. Scalable motion vector coding algorithms based on the integer wavelet transform followed by embedded coding of the wavelet coefficients were recently proposed. In this paper, a new and fundamentally different scalable motion vector codec (MVC) using median-based motion vector prediction is proposed. Extensive experimental results demonstrate that the proposed MVC systematically outperforms the wavelet-based state-of-the-art solutions. To be able to take advantage of the proposed scalable MVC, a rate allocation mechanism capable of optimally dividing the available rate among texture and motion information is required. Two rate allocation strategies are proposed and compared. The proposed MVC and rate allocation schemes are incorporated into an SDMCTF-based video codec and the benefits of scalable motion vector coding are experimentally demonstrated.

  6. A host species-informative internal control for molecular assessment of African swine fever virus infection rates in the African sylvatic cycle Ornithodoros vector.

    PubMed

    Bastos, A D S; Arnot, L F; Jacquier, M D; Maree, S

    2009-12-01

    African swine fever virus (ASFV) infection in adult Ornithodoros porcinus (Murry 1877, sensuWalton 1979) ticks collected from warthog burrows in southern and East Africa was assessed using a duplex genomic amplification approach that is informative with respect to the invertebrate host species and infecting sylvatic cycle virus. DNA extracted from individual ticks was used as template for the simultaneous amplification of a C-terminal 478-bp ASFV p72 gene region and a approximately 313-bp fragment of the tick mitochondrial 16S rRNA gene, under optimized reaction conditions. Within-warthog burrow infection rates ranged from 0% to 43% using this approach, and phylogenetic analysis of 16S gene sequences revealed the presence of three geographically discrete O. porcinus lineages, but no support for subspecies recognition. False negatives are precluded by the inclusion of host species-informative primers that ensure the DNA integrity of cytoplasmically located genome extracts. In addition, infection rate estimates are further improved as false positives arising from carry-over contamination when performing a two-step nested polymerase chain reaction are negated by the one-step approach. Phylogenetic comparison of full-length virus gene sequences with the partial C-terminal p72 gene target confirmed the epidemiological utility of the latter in a sylvatic setting. The method is therefore of particular value in studies assessing the prevalence and diversity of ASFV in relation to the African sylvatic tick vector and holds potential for investigating the role of alternative tick species in virus maintenance and transmission. PMID:19941606

  7. Flight-Determined, Subsonic, Lateral-Directional Stability and Control Derivatives of the Thrust-Vectoring F-18 High Angle of Attack Research Vehicle (HARV), and Comparisons to the Basic F-18 and Predicted Derivatives

    NASA Technical Reports Server (NTRS)

    Iliff, Kenneth W.; Wang, Kon-Sheng Charles

    1999-01-01

    The subsonic, lateral-directional, stability and control derivatives of the thrust-vectoring F-1 8 High Angle of Attack Research Vehicle (HARV) are extracted from flight data using a maximum likelihood parameter identification technique. State noise is accounted for in the identification formulation and is used to model the uncommanded forcing functions caused by unsteady aerodynamics. Preprogrammed maneuvers provided independent control surface inputs, eliminating problems of identifiability related to correlations between the aircraft controls and states. The HARV derivatives are plotted as functions of angles of attack between 10deg and 70deg and compared to flight estimates from the basic F-18 aircraft and to predictions from ground and wind tunnel tests. Unlike maneuvers of the basic F-18 aircraft, the HARV maneuvers were very precise and repeatable, resulting in tightly clustered estimates with small uncertainty levels. Significant differences were found between flight and prediction; however, some of these differences may be attributed to differences in the range of sideslip or input amplitude over which a given derivative was evaluated, and to differences between the HARV external configuration and that of the basic F-18 aircraft, upon which most of the prediction was based. Some HARV derivative fairings have been adjusted using basic F-18 derivatives (with low uncertainties) to help account for differences in variable ranges and the lack of HARV maneuvers at certain angles of attack.

  8. Conceptual design of a thrust-vectoring tailcone for underwater robotics

    E-print Network

    Nawrot, Michael T

    2012-01-01

    Thrust-vectoring on Autonomous Underwater Vehicles is an appealing directional-control solution because it improves turning radius capabilities. Unfortunately, thrust-vectoring requires the entire propulsion system be ...

  9. Vector WIMP Miracle

    E-print Network

    Tomohiro Abe; Mitsuru Kakizaki; Shigeki Matsumoto; Osamu Seto

    2012-05-25

    Weakly interacting massive particle (WIMP) is well known to be a good candidate for dark matter, and it is also predicted by many new physics models beyond the standard model at the TeV scale. We found that, if the WIMP is a vector particle (spin one particle) which is associated with some gauge symmetry broken at the TeV scale, the higgs mass is often predicted to be 120--125 GeV, which is very consistent with the result of higgs searches recently reported by ATLAS and CMS collaborations at the Large Hadron Collider experiment. In this letter, we consider the vector WIMP using a non-linear sigma model in order to confirm this result as general as possible in a bottom-up approach. Near-future prospects to detect the vector WIMP at both direct and indirect detection experiments of dark matter are also discussed.

  10. Vector financial rogue waves

    NASA Astrophysics Data System (ADS)

    Yan, Zhenya

    2011-11-01

    The coupled nonlinear volatility and option pricing model presented recently by Ivancevic is investigated, which generates a leverage effect, i.e., stock volatility is (negatively) correlated to stock returns, and can be regarded as a coupled nonlinear wave alternative of the Black-Scholes option pricing model. In this Letter, we analytically propose vector financial rogue waves of the coupled nonlinear volatility and option pricing model without an embedded w-learning. Moreover, we exhibit their dynamical behaviors for chosen different parameters. The vector financial rogue wave (rogon) solutions may be used to describe the possible physical mechanisms for the rogue wave phenomena and to further excite the possibility of relative researches and potential applications of vector rogue waves in the financial markets and other related fields.

  11. Viral Vectors for in Vivo Gene Transfer

    NASA Astrophysics Data System (ADS)

    Thévenot, E.; Dufour, N.; Déglon, N.

    The transfer of DNA into the nucleus of a eukaryotic cell (gene transfer) is a central theme of modern biology. The transfer is said to be somatic when it refers to non-germline organs of a developed individual, and germline when it concerns gametes or the fertilised egg of an animal, with the aim of transmitting the relevant genetic modification to its descendents [1]. The efficient introduction of genetic material into a somatic or germline cell and the control of its expression over time have led to major advances in understanding how genes work in vivo, i.e., in living organisms (functional genomics), but also to the development of innovative therapeutic methods (gene therapy). The efficiency of gene transfer is conditioned by the vehicle used, called the vector. Desirable features for a vector are as follows: Easy to produce high titer stocks of the vector in a reproducible way. Absence of toxicity related to transduction (transfer of genetic material into the target cell, and its expression there) and no immune reaction of the organism against the vector and/or therapeutic protein. Stability in the expression of the relevant gene over time, and the possibility of regulation, e.g., to control expression of the therapeutic protein on the physiological level, or to end expression at the end of treatment. Transduction of quiescent cells should be as efficient as transduction of dividing cells. Vectors currently used fall into two categories: non-viral and viral vectors. In non-viral vectors, the DNA is complexed with polymers, lipids, or cationic detergents (described in Chap. 3). These vectors have a low risk of toxicity and immune reaction. However, they are less efficient in vivo than viral vectors when it comes to the number of cells transduced and long-term transgene expression. (Naked DNA transfer or electroporation is rather inefficient in the organism. This type of gene transfer will not be discussed here, and the interested reader is referred to the review [2].) For this reason, it is mainly viral vectors that are used for gene transfer in animals and humans.

  12. The effectiveness of permethrin-treated deer stations for control of the Lyme disease vector Ixodes scapularis on Cape Cod and the islands: a five year experiment

    EPA Science Inventory

    The use of animal host-targeted pesticide application to control blacklegged ticks, which transmit the Lyme disease bacterium between wildlife hosts and humans, is receiving increased attention as an approach to Lyme disease risk management. Included among the attractive features...

  13. The effectiveness of permethrin-treated deer stations for control of the Lyme disease vector Ixodes scapularis on Cape Cod and the Islands

    EPA Science Inventory

    The use of animal host-targeted pesticide application to control blacklegged ticks, which transmit the Lyme disease bacterium between wildlife hosts and humans, is receiving increased attention as an approach to Lyme disease risk management. Included among the attractive feature...

  14. Bunyavirus-Vector Interactions

    PubMed Central

    Horne, Kate McElroy; Vanlandingham, Dana L.

    2014-01-01

    The Bunyaviridae family is comprised of more than 350 viruses, of which many within the Hantavirus, Orthobunyavirus, Nairovirus, Tospovirus, and Phlebovirus genera are significant human or agricultural pathogens. The viruses within the Orthobunyavirus, Nairovirus, and Phlebovirus genera are transmitted by hematophagous arthropods, such as mosquitoes, midges, flies, and ticks, and their associated arthropods not only serve as vectors but also as virus reservoirs in many cases. This review presents an overview of several important emerging or re-emerging bunyaviruses and describes what is known about bunyavirus-vector interactions based on epidemiological, ultrastructural, and genetic studies of members of this virus family. PMID:25402172

  15. Bunyavirus-vector interactions.

    PubMed

    Horne, Kate McElroy; Vanlandingham, Dana L

    2014-11-01

    The Bunyaviridae family is comprised of more than 350 viruses, of which many within the Hantavirus, Orthobunyavirus, Nairovirus, Tospovirus, and Phlebovirus genera are significant human or agricultural pathogens. The viruses within the Orthobunyavirus, Nairovirus, and Phlebovirus genera are transmitted by hematophagous arthropods, such as mosquitoes, midges, flies, and ticks, and their associated arthropods not only serve as vectors but also as virus reservoirs in many cases. This review presents an overview of several important emerging or re-emerging bunyaviruses and describes what is known about bunyavirus-vector interactions based on epidemiological, ultrastructural, and genetic studies of members of this virus family. PMID:25402172

  16. Impact of Malaria Vector Control Interventions at the Beginning of a Malaria Elimination Stage in a Dominant Area of Anopheles anthropophagus, Hubei Province, China.

    PubMed

    Li, K J; Cai, S X; Lin, W; Xia, J; Pi, Q; Hu, L Q; Huang, G Q; Pei, S J; Zhang, H X

    2015-10-01

    Three towns with similar socio-ecological characteristics, malaria morbidities, and populations were selected for this study to explore economic and effective malaria control measures.The sources of infection were controlled in each town. Impregnated mosquito nets with 2.5% deltamethrin (15 mg/m(2)) combined with residual spraying of 5% cypermethrin (25 mg/m(2)) was implemented in cattle and pig pens, as well as in crowded sites in Chenji, whereas the mosquito nets were treated with 2.5% deltamethrin only in Guanqiao Town. All the control measures implemented in Fengling (control town) were the same as those implemented in the towns of Chenji and Guanqiao, except for mosquito elimination control. Results were evaluated and compared based on pathogens and entomology. The densities of Anopheles anthropophagus mosquitoes in houses, outside houses (man bait), as well as in cattle pens and pig pens were reduced by 100%, 71.96%, 94.01%, and 67.42%, respectively at all 4 sites in Chenji Town, whereas the density increased at 1 site (the outside house [man bait]) by 12.38%, while the densities at the other 3 sites (in houses, cattle pens and pig pens) were reduced by 99.63%, 18.71% and 69.44% respectively in Guanqiao Town. The biting rates of An. anthropophagus in the 3 towns were 0.11, 0.22, and 1.1 respectively in Chenji, Guanqiao, and Fengling. The incidence of malaria in the 3 towns decreased by 73.12%, 57.71%, and 65.71% in terms of annual average. Both impregnated mosquito nets combined with residual spraying and impregnated mosquito nets only reduced the density of An. anthropophagus in houses in the 2 towns, but reduction was more rapid in Chenji Town. PMID:25993491

  17. 7/9/10 2:34 PMWHO | Human African trypanosomiasis: number of new cases drops to historically low level in 50 years Page 1 of 2http://www.who.int/neglected_diseases/integrated_media/integrated_media_hat_june_2010/en/index.html

    E-print Network

    Cross, George

    level in 50 years Page 1 of 2http://www.who.int/neglected_diseases and projects Neglected tropical diseases Diseases Preventive chemotherapy and transmission control Innovative and intensified disease management Vector ecology and management Neglected zoonotic diseases Neglected tropical

  18. The Apple Snail Pomacea canaliculata, a Novel Vector of the Rat Lungworm, Angiostrongylus cantonensis: its Introduction, Spread, and Control in China

    PubMed Central

    Wu, Zhong-Dao; Lun, Zhao-Rong

    2013-01-01

    The freshwater apple snail Pomacea canaliculata was introduced to Taiwan then to mainland China in the early 1980s from Argentina, its native region, for the purpose of aquaculture. Because of the lack of natural enemies and its tolerance of a wide range of environmental conditions, both its abundance and distribution have dramatically increased and it has become a harmful species to local agriculture and other native species in many areas of China. Unfortunately, the snail also acts as an intermediate host of Angiostrongylus cantonensis, and has been implicated in transfer of the parasite to people, resulting in angiostrongyliasis manifested as eosinophilic meningitis. Efforts to prevent its further spread and population expansion were initiated many years ago, including the use of chemicals and biological control agents to control the snail. PMID:23901377

  19. The effectiveness of permethrin-treated deer stations for control of the Lyme disease vector Ixodes scapularis on Cape Cod and the islands: a five-year experiment

    PubMed Central

    2014-01-01

    Background The use of animal host-targeted pesticide application to control blacklegged ticks, which transmit the Lyme disease bacterium between wildlife hosts and humans, is receiving increased attention as an approach to Lyme disease risk management. Included among the attractive features of host-targeted approaches is the reduced need for broad-scale pesticide usage. In the eastern USA, one of the best-known of these approaches is the corn-baited “4-poster” deer feeding station, so named because of the four pesticide-treated rollers that surround the bait troughs. Wildlife visitors to these devices receive an automatic topical application of acaricide, which kills attached ticks before they can reproduce. We conducted a 5-year controlled experiment to estimate the effects of 4-poster stations on tick populations in southeastern Massachusetts, where the incidence of Lyme disease is among the highest in the USA. Methods We deployed a total of forty-two 4-posters among seven treatment sites and sampled for nymph and adult ticks at these sites and at seven untreated control sites during each year of the study. Study sites were distributed among Cape Cod, Martha’s Vineyard, and Nantucket. The density of 4-poster deployment was lower than in previous 4-poster studies and resembled or possibly exceeded the levels of effort considered by county experts to be feasible for Lyme disease risk managers. Results Relative to controls, blacklegged tick abundance at treated sites was reduced by approximately 8.4%, which is considerably less than in previous 4-poster studies. Conclusions In addition to the longer duration and greater replication in our study compared to others, possible but still incomplete explanations for the smaller impact we observed include the lower density of 4-poster deployment as well as landscape and mammalian community characteristics that may complicate the ecological relationship between white-tailed deer and blacklegged tick populations. PMID:24965139

  20. Vector wind gust model

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1984-01-01

    The development of a vector wind gust model through statistical analysis is described. Wind perturbation statistics which include location, altitude, season, and wavelength range are used in the synthesis of detailed wing profiles. These profiles provide the basis for the establishment of improved discrete gust design criteria guidelines for ascending launch vehicles.

  1. Vector potential methods

    NASA Technical Reports Server (NTRS)

    Hafez, M.

    1989-01-01

    Vector potential and related methods, for the simulation of both inviscid and viscous flows over aerodynamic configurations, are briefly reviewed. The advantages and disadvantages of several formulations are discussed and alternate strategies are recommended. Scalar potential, modified potential, alternate formulations of Euler equations, least-squares formulation, variational principles, iterative techniques and related methods, and viscous flow simulation are discussed.

  2. CALCULUS III Vector Calculus

    E-print Network

    Sutherland, Scott

    Calculus: concepts and contexts, by James Stewart, Brooks/Cole, 1998. RECITATIONS: Fr 12:40-1:35, ROOM SBMAT 205 CALCULUS III Vector Calculus SPRING 2000 This course represents the third semester in the standard Calculus sequence. We will develop the theory and practice of di#11;erentiation and integration

  3. Support vector machines

    NASA Technical Reports Server (NTRS)

    Garay, Michael J.; Mazzoni, Dominic; Davies, Roger; Wagstaff, Kiri

    2004-01-01

    Support Vector Machines (SVMs) are a type of supervised learning algorith,, other examples of which are Artificial Neural Networks (ANNs), Decision Trees, and Naive Bayesian Classifiers. Supervised learning algorithms are used to classify objects labled by a 'supervisor' - typically a human 'expert.'.

  4. Killing vectors and anisotropy

    E-print Network

    J. P. Krisch; E. N. Glass

    2009-08-03

    We consider an action that can generate fluids with three unequal stresses for metrics with a spacelike Killing vector. The parameters in the action are directly related to the stress anisotropies. The field equations following from the action are applied to an anisotropic cosmological expansion and an extension of the Gott-Hiscock cosmic string.

  5. System for Automated Calibration of Vector Modulators

    NASA Technical Reports Server (NTRS)

    Lux, James; Boas, Amy; Li, Samuel

    2009-01-01

    Vector modulators are used to impose baseband modulation on RF signals, but non-ideal behavior limits the overall performance. The non-ideal behavior of the vector modulator is compensated using data collected with the use of an automated test system driven by a LabVIEW program that systematically applies thousands of control-signal values to the device under test and collects RF measurement data. The technology innovation automates several steps in the process. First, an automated test system, using computer controlled digital-to-analog converters (DACs) and a computer-controlled vector network analyzer (VNA) systematically can apply different I and Q signals (which represent the complex number by which the RF signal is multiplied) to the vector modulator under test (VMUT), while measuring the RF performance specifically, gain and phase. The automated test system uses the LabVIEW software to control the test equipment, collect the data, and write it to a file. The input to the Lab - VIEW program is either user-input for systematic variation, or is provided in a file containing specific test values that should be fed to the VMUT. The output file contains both the control signals and the measured data. The second step is to post-process the file to determine the correction functions as needed. The result of the entire process is a tabular representation, which allows translation of a desired I/Q value to the required analog control signals to produce a particular RF behavior. In some applications, corrected performance is needed only for a limited range. If the vector modulator is being used as a phase shifter, there is only a need to correct I and Q values that represent points on a circle, not the entire plane. This innovation has been used to calibrate 2-GHz MMIC (monolithic microwave integrated circuit) vector modulators in the High EIRP Cluster Array project (EIRP is high effective isotropic radiated power). These calibrations were then used to create correction tables to allow the commanding of the phase shift in each of four channels used as a phased array for beam steering of a Ka-band (32-GHz) signal. The system also was the basis of a breadboard electronic beam steering system. In this breadboard, the goal was not to make systematic measurements of the properties of a vector modulator, but to drive the breadboard with a series of test patterns varying in phase and amplitude. This is essentially the same calibration process, but with the difference that the data collection process is oriented toward collecting breadboard performance, rather than the measurement of output from a network analyzer.

  6. Impact of Anthropogenic Environmental Alterations on Vector-Borne Diseases

    PubMed Central

    Vora, Neil

    2008-01-01

    The spread of infectious vector-borne diseases involves at least 3 organisms: a parasite, a vector, and a host. Alterations to the natural environment may change the context within which these entities interact, thus potentially affecting vector-borne disease epidemiology. In this review, examples are presented in which human-driven ecological changes may be contributing to the spread of vector-borne diseases. Such changes include deforestation, agriculture and animal husbandry, water control projects, urbanization, loss of biodiversity, introduction of alien species, and climate change. The global environment is currently being degraded at an alarming pace, potentially placing human populations at increasing risk for unnecessary and preventable outbreaks of vector-borne diseases. Further research is needed to improve our ability to predict and prevent emergence and reemergence of vector-borne diseases from environmental alterations. PMID:19099032

  7. Impact of anthropogenic environmental alterations on vector-borne diseases.

    PubMed

    Vora, Neil

    2008-01-01

    The spread of infectious vector-borne diseases involves at least 3 organisms: a parasite, a vector, and a host. Alterations to the natural environment may change the context within which these entities interact, thus potentially affecting vector-borne disease epidemiology. In this review, examples are presented in which human-driven ecological changes may be contributing to the spread of vector-borne diseases. Such changes include deforestation, agriculture and animal husbandry, water control projects, urbanization, loss of biodiversity, introduction of alien species, and climate change. The global environment is currently being degraded at an alarming pace, potentially placing human populations at increasing risk for unnecessary and preventable outbreaks of vector-borne diseases. Further research is needed to improve our ability to predict and prevent emergence and reemergence of vector-borne diseases from environmental alterations. PMID:19099032

  8. Maintenance of residual activity of Bt toxin by using natural and synthetic dyes: a novel approach for sustainable mosquito vector control.

    PubMed

    Chandrashekhar, Patil; Rahul, Suryawanshi; Hemant, Borase; Chandrakant, Narkhede; Bipinchandra, Salunke; Satish, Patil

    2015-12-01

    Mosquito control protein from Bacillus thuringiensis gets inactivated with exposure to sunlight. To address this issue, the potential of synthetic and natural dye was investigated as sunlight protectants. Bt SV2 in absence of dyes when exposed to sunlight showed reduced effectiveness against the fourth instars of mosquito larvae. Whereas acriflavin, congo red and violacein were able to maintain 86.4%, 91.6% and 82.2% mosquito larvicidal efficacy of Bt SV2 against IVth instars larvae of Anopheles stephensi Meigen after exposure to sunlight. Similarly, beetroot dye, acriflavin, congo red and violacein maintained 98.4%, 97.1%, 90.8% and 70.7% larvicidal activities against Aedes aegypti Linnaeus after sunlight exposure. Prodigiosin was found to be the best photo-protectant by simultaneously protecting and enhancing Bt activity by 6.16% and 22.16% against A. stephensi and A. aegypti, respectively. Combination of dyes with Bt formulations can be a good strategy for mosquito control programmes in tropical and sub-tropical regions. PMID:25699646

  9. Stability of Horndeski vector-tensor interactions

    SciTech Connect

    Jiménez, Jose Beltrán; Durrer, Ruth; Heisenberg, Lavinia; Thorsrud, Mikjel E-mail: ruth.durrer@unige.ch E-mail: mikjel.thorsrud@astro.uio.no

    2013-10-01

    We study the Horndeski vector-tensor theory that leads to second order equations of motion and contains a non-minimally coupled abelian gauge vector field. This theory is remarkably simple and consists of only 2 terms for the vector field, namely: the standard Maxwell kinetic term and a coupling to the dual Riemann tensor. Furthermore, the vector sector respects the U(1) gauge symmetry and the theory contains only one free parameter, M{sup 2}, that controls the strength of the non-minimal coupling. We explore the theory in a de Sitter spacetime and study the presence of instabilities and show that it corresponds to an attractor solution in the presence of the vector field. We also investigate the cosmological evolution and stability of perturbations in a general FLRW spacetime. We find that a sufficient condition for the absence of ghosts is M{sup 2} > 0. Moreover, we study further constraints coming from imposing the absence of Laplacian instabilities. Finally, we study the stability of the theory in static and spherically symmetric backgrounds (in particular, Schwarzschild and Reissner-Nordström-de Sitter). We find that the theory, quite generally, do have ghosts or Laplacian instabilities in regions of spacetime where the non-minimal interaction dominates over the Maxwell term. We also calculate the propagation speed in these spacetimes and show that superluminality is a quite generic phenomenon in this theory.

  10. Lead Optimization of a Pyrazole Sulfonamide Series of Trypanosoma bruceiN-Myristoyltransferase Inhibitors: Identification and Evaluation of CNS Penetrant Compounds as Potential Treatments for Stage 2 Human African Trypanosomiasis

    PubMed Central

    2014-01-01

    Trypanosoma bruceiN-myristoyltransferase (TbNMT) is an attractive therapeutic target for the treatment of human African trypanosomiasis (HAT). From previous studies, we identified pyrazole sulfonamide, DDD85646 (1), a potent inhibitor of TbNMT. Although this compound represents an excellent lead, poor central nervous system (CNS) exposure restricts its use to the hemolymphatic form (stage 1) of the disease. With a clear clinical need for new drug treatments for HAT that address both the hemolymphatic and CNS stages of the disease, a chemistry campaign was initiated to address the shortfalls of this series. This paper describes modifications to the pyrazole sulfonamides which markedly improved blood–brain barrier permeability, achieved by reducing polar surface area and capping the sulfonamide. Moreover, replacing the core aromatic with a flexible linker significantly improved selectivity. This led to the discovery of DDD100097 (40) which demonstrated partial efficacy in a stage 2 (CNS) mouse model of HAT. PMID:25412409

  11. The Variable Vector Countermeasure Suit for space habitation and exploration

    E-print Network

    Vasquez, Rebecca (Rebecca Ann)

    2014-01-01

    The Variable Vector Countermeasure Suit (V2Suit) is a countermeasure suit for sensorimotor adaptation and musculoskeletal deconditioning in microgravity. The V2suit will consist of modules containing arrays of control ...

  12. Vector Magnetograph Design

    NASA Technical Reports Server (NTRS)

    Chipman, Russell A.

    1996-01-01

    This report covers work performed during the period of November 1994 through March 1996 on the design of a Space-borne Solar Vector Magnetograph. This work has been performed as part of a design team under the supervision of Dr. Mona Hagyard and Dr. Alan Gary of the Space Science Laboratory. Many tasks were performed and this report documents the results from some of those tasks, each contained in the corresponding appendix. Appendices are organized in chronological order.

  13. Silk fibroin nanoparticles constitute a vector for controlled release of resveratrol in an experimental model of inflammatory bowel disease in rats

    PubMed Central

    Lozano-Pérez, Antonio Abel; Rodriguez-Nogales, Alba; Ortiz-Cullera, Víctor; Algieri, Francesca; Garrido-Mesa, José; Zorrilla, Pedro; Rodriguez-Cabezas, M Elena; Garrido-Mesa, Natividad; Utrilla, M Pilar; De Matteis, Laura; de la Fuente, Jesús Martínez; Cenis, José Luis; Gálvez, Julio

    2014-01-01

    Purpose We aimed to evaluate the intestinal anti-inflammatory properties of silk fibroin nanoparticles, around 100 nm in size, when loaded with the stilbene compound resveratrol, in an experimental model of rat colitis. Methods Nanoparticles were loaded with resveratrol by adsorption. The biological effects of the resveratrol-loaded nanoparticles were tested both in vitro, in a cell culture of RAW 264.7 cells (mouse macrophages), and in vivo, in the trinitrobenzenesulfonic acid model of rat colitis, when administered intracolonically. Results The resveratrol liberation in 1× phosphate-buffered saline (PBS; pH 7.4) was characterized by fast liberation, reaching the solubility limit in 3 hours, which was maintained over a period of 80 hours. The in vitro assays revealed immunomodulatory properties exerted by these resveratrol-loaded nanoparticles since they promoted macrophage activity in basal conditions and inhibited this activity when stimulated with lipopolysaccharide. The in vivo experiments showed that after evaluation of the macroscopic symptoms, inflammatory markers, and intestinal barrier function, the fibroin nanoparticles loaded with resveratrol had a better effect than the single treatments, being similar to that produced by the glucocorticoid dexamethasone. Conclusion Silk fibroin nanoparticles constitute an attractive strategy for the controlled release of resveratrol, showing immunomodulatory properties and intestinal anti-inflammatory effects. PMID:25285004

  14. Risk Behavior among Women enrolled in a Randomized Controlled Efficacy Trial of an Adenoviral Vector Vaccine to Prevent HIV Acquisition: the Step Study

    PubMed Central

    Novak, Richard M.; Metch, Barbara; Buchbinder, Susan; Cabello, Robinson; Donastorg, Yeycy; Figoroa, John-Peter; Adbul-Jauwad, Hend; Joseph, Patrice; Koenig, Ellen; Metzger, David; Sobieszycz, Magda; Tyndall, Mark; Zorilla, Carmen

    2013-01-01

    Objectives Report of risk behavior, HIV incidence, and pregnancy rates among women participating in the Step Study, a phase IIB trial of MRKAd5 HIV-1 gag/pol/nef vaccine in HIV-negative individuals who were at high risk of HIV-1. Design Prospective multicenter, double-blinded, placebo-controlled trial Methods Women were from North American (NA) and Caribbean and South America (CSA) sites. Risk behavior was collected at screening and 6-month intervals. Differences in characteristics between groups were tested with Chi-square, two-sided Fisher’s exact tests, and Wilcoxon rank sum tests. Generalized estimating equation models were used to assess behavioral change. Results Among 1134 enrolled women, the median number of male partners was 18; 73.8% reported unprotected vaginal sex, 15.9% unprotected anal sex and 10.8% evidence of a sexually transmitted infection in the 6 months prior to baseline. With 3344 person-years (p–y) of follow up, there were 15 incident HIV infections: incidence rate was 0.45 per 100/p-y (95% CI 0.25, 0.74). Crack cocaine use in both regions (relative risk [RR]=2.4 [1.7,3.3]) and in CSA, unprotected anal sex (RR=6.4 [3.8. 10.7]) and drug use (RR=4.1 [2.1, 8.0]) were baseline risk behaviors associated with HIV acquisition. There was a marked reduction in risk behaviors after study enrollment with some recurrence in unprotected vaginal sex. Of 963 non-sterilized women, 304 (31.6%) became pregnant. Conclusions Crack cocaine use and unprotected anal sex are important risk criteria to identify high-risk women for HIV efficacy trials. Pregnancy during the trial was a common occurrence and needs to be considered in trial planning for prevention trials in women. PMID:23807272

  15. Vector representation of tourmaline compositions

    NASA Technical Reports Server (NTRS)

    Burt, Donald M.

    1989-01-01

    The vector method for representing mineral compositions of amphibole and mica groups is applied to the tourmaline group. Consideration is given to the methods for drawing the relevant vector diagrams, relating the exchange vectors to one another, and contouring the diagrams for constant values of Na, Ca, Li, Fe, Mg, Al, Si, and OH. The method is used to depict a wide range of possible tourmaline end-member compositions and solid solutions, starting from a single point. In addition to vector depictions of multicomponent natural tourmalines, vectors are presented for simpler systems such as (Na,Al)-tourmalines, alkali-free tourmalines, and elbaites.

  16. Control of the African trypanosomiases with special reference to land use*

    PubMed Central

    Ford, John

    1969-01-01

    There is a need to reassess the role of the trypanosomiases, both human and animal, in African ecology and economy. Withdrawal of control services from the Congo basin was followed by a resurgence of infection from ancient foci, many of them thought to have been extinguished. Successful elimination of Glossina in savanna habitats has sometimes been followed by reinvasion causing massive epizootics. Elsewhere continued recession of the tsetse fly has been followed by cattle population growth which is periodically interrupted by catastrophic pasture famines. Efficiency of control rather than large-scale eradication should be the immediate aim. Efficient control keeps trypanosomiasis at a tolerable level in relation to the competence of medical and veterinary services and ensures that the beneficial effects of disease in maintaining a balance between natural resource potential of the continent and the energy output of its inhabitants, are retained until they can be replaced by new social and economic controls integrated in local cultures. Many ideas about control planning formulated before 1960 are now irrelevant. To provide foundations for a new policy 3 requirements must be fulfilled. The first is to understand the nature of natural foci of infection of trypanosomiasis; the second is to collate knowledge of land-use potentials of the fly-belts; the third is to find a means of integrating information to achieve balanced control programmes. To do this a formal mathematical study of the epidemiology and epizootiology of the trypanosomiases should be initiated. PMID:5307600

  17. Effects of internal yaw-vectoring devices on the static performance of a pitch-vectoring nonaxisymmetric convergent-divergent nozzle

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.

    1993-01-01

    An investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to evaluate the internal performance of a nonaxisymmetric convergent divergent nozzle designed to have simultaneous pitch and yaw thrust vectoring capability. This concept utilized divergent flap deflection for thrust vectoring in the pitch plane and flow-turning deflectors installed within the divergent flaps for yaw thrust vectoring. Modifications consisting of reducing the sidewall length and deflecting the sidewall outboard were investigated as means to increase yaw-vectoring performance. This investigation studied the effects of multiaxis (pitch and yaw) thrust vectoring on nozzle internal performance characteristics. All tests were conducted with no external flow, and nozzle pressure ratio was varied from 2.0 to approximately 13.0. The results indicate that this nozzle concept can successfully generate multiaxis thrust vectoring. Deflection of the divergent flaps produced resultant pitch vector angles that, although dependent on nozzle pressure ratio, were nearly equal to the geometric pitch vector angle. Losses in resultant thrust due to pitch vectoring were small or negligible. The yaw deflectors produced resultant yaw vector angles up to 21 degrees that were controllable by varying yaw deflector rotation. However, yaw deflector rotation resulted in significant losses in thrust ratios and, in some cases, nozzle discharge coefficient. Either of the sidewall modifications generally reduced these losses and increased maximum resultant yaw vector angle. During multiaxis (simultaneous pitch and yaw) thrust vectoring, little or no cross coupling between the thrust vectoring processes was observed.

  18. Climate and Population Health Vulnerabilities to Vector-Borne Diseases: Increasing Resilience Under Climate Change Conditions in Africa

    NASA Astrophysics Data System (ADS)

    Ceccato, P.; McDonald, K. C.; Podest, E.; De La Torre Juarez, M.; Kruczkiewicz, A.; Lessel, J.; Jensen, K.; Thomson, M. C.

    2014-12-01

    The International Research Institute for Climate and Society (IRI), the City University of New York (CUNY) and NASA Jet Propulsion Laboratory (JPL) in collaboration with NASA SERVIR are developing tools to monitor climate variables (precipitation, temperature, vegetation, water bodies, inundation) that help projects in Africa to increase resilience to climate change for vector-borne diseases (i.e. malaria, trypanosomiasis, leishmaniasis, and schistosomiasis). Through the development of new products to monitor precipitation, water bodies and inundation, IRI, CUNY and JPL provide tools and capacity building to research communities, ministries of health and World Health Organization in Africa to: 1) Develop research teams' ability to appropriately use climate data as part of their research 2) Enable research teams and ministries to integrate climate information into social and economic drivers of vulnerability and opportunities for adaptation to climate change 3) Inform better policies and programs for climate change adaptation. This oral presentation will demonstrate how IRI, CUNY, and JPL developed new products, tools and capacity building to achieve the three objectives mentioned above.

  19. Disease prevention and anti-vector campaigns: insects.

    PubMed

    Esterhuizen, J

    2015-04-01

    Control of insect vector populations is an integral part of disease management but has many challenges. Area-wide campaigns, mainly based on insecticide administration, are most effective for control of insect populations, whereas disease prevention is more localised and protects a smaller number of animals against insect vector contact. Various control and prevention techniques are available for use against most insectvectors and are illustrated here by focusing on two important insect groups: biting midges and tsetse flies. Biting midges (Culicoides) present a major threat and challenge to disease and vector control because of limited large-scale control options and the huge population sizes and wide distribution of these insects. Localised disease prevention forms the basis for control, and there is a need for better understanding of the ecology and biology of these insects in order to develop large-scale control techniques. The necessary techniques to effectively control tsetse flies (Glossina) and trypanosomosis exist for both localised and area-wide control. The development of a new, cost-efficient device has had a significant impact in the control of both human and animal trypanosomosis. This is especially relevant in Uganda, where the movement of livestock for trading purposes is implicated in disease distribution and poses an immediate health threat where the two forms of the disease overlap. Although many successes have been achieved, continued research and development is needed to keep abreast of the multitude of challenges in insect vector control. PMID:26470462

  20. Viral vectors and delivery strategies for CNS gene therapy

    PubMed Central

    Gray, Steven J; Woodard, Kenton T; Samulski, R Jude

    2015-01-01

    This review aims to provide a broad overview of the targets, challenges and potential for gene therapy in the CNS, citing specific examples. There are a broad range of therapeutic targets, with very different requirements for a suitable viral vector. By utilizing different vector tropisms, novel routes of administration and engineered promoter control, transgenes can be targeted to specific therapeutic applications. Viral vectors have proven efficacious in preclinical models for several disease applications, spurring several clinical trials. While the field has pushed the limits of existing adeno-associated virus-based vectors, a next generation of vectors based on rational engineering of viral capsids should expand the application of gene therapy to be more effective in specific therapeutic applications. PMID:22833965

  1. Novel chemicals for vector surveillance and control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 1942, the United States Department of Agriculture (USDA) has developed repellents and insecticides for the U.S. military. Within the archives, there exist similarly structured compounds that function as repellents against mosquitoes. We examined subsets of these compounds by artificial neural...

  2. An adaptive vector quantization scheme

    NASA Technical Reports Server (NTRS)

    Cheung, K.-M.

    1990-01-01

    Vector quantization is known to be an effective compression scheme to achieve a low bit rate so as to minimize communication channel bandwidth and also to reduce digital memory storage while maintaining the necessary fidelity of the data. However, the large number of computations required in vector quantizers has been a handicap in using vector quantization for low-rate source coding. An adaptive vector quantization algorithm is introduced that is inherently suitable for simple hardware implementation because it has a simple architecture. It allows fast encoding and decoding because it requires only addition and subtraction operations.

  3. VLSI Processor For Vector Quantization

    NASA Technical Reports Server (NTRS)

    Tawel, Raoul

    1995-01-01

    Pixel intensities in each kernel compared simultaneously with all code vectors. Prototype high-performance, low-power, very-large-scale integrated (VLSI) circuit designed to perform compression of image data by vector-quantization method. Contains relatively simple analog computational cells operating on direct or buffered outputs of photodetectors grouped into blocks in imaging array, yielding vector-quantization code word for each such block in sequence. Scheme exploits parallel-processing nature of vector-quantization architecture, with consequent increase in speed.

  4. Localization and vector spherical harmonics

    NASA Astrophysics Data System (ADS)

    von Brecht, James H.

    2016-01-01

    This paper establishes the following localization property for vector spherical harmonics: a wide class of non-local, vector-valued operators reduce to local, multiplication-type operations when applied to a vector spherical harmonic. As localization occurs in a very precise, quantifiable and explicitly computable fashion, the localization property provides a set of useful formulae for analyzing vector-valued fractional diffusion and non-local differential equations defined on S d - 1. As such analyses require a detailed understanding of operators for which localization occurs, we provide several applications of the result in the context of non-local differential equations.

  5. Human adenovirus 5-vectored Plasmodium falciparum NMRC-M3V-Ad-PfCA vaccine encoding CSP and AMA1 is safe, well-tolerated and immunogenic but does not protect against controlled human malaria infection

    PubMed Central

    Tamminga, Cindy; Sedegah, Martha; Maiolatesi, Santina; Fedders, Charlotte; Reyes, Sharina; Reyes, Anatalio; Vasquez, Carlos; Alcorta, Yolanda; Chuang, Ilin; Spring, Michele; Kavanaugh, Michael; Ganeshan, Harini; Huang, Jun; Belmonte, Maria; Abot, Esteban; Belmonte, Arnel; Banania, JoGlenna; Farooq, Fouzia; Murphy, Jittawadee; Komisar, Jack; Richie, Nancy O; Bennett, Jason; Limbach, Keith; Patterson, Noelle B; Bruder, Joseph T; Shi, Meng; Miller, Edward; Dutta, Sheetij; Diggs, Carter; Soisson, Lorraine A; Hollingdale, Michael R; Epstein, Judith E; Richie, Thomas L

    2013-01-01

    Background: In a prior study, a DNA prime / adenovirus boost vaccine (DNA/Ad) expressing P. falciparum circumsporozoite protein (CSP) and apical membrane antigen-1 (AMA1) (NMRC-M3V-D/Ad-PfCA Vaccine) induced 27% protection against controlled human malaria infection (CHMI). To investigate the contribution of DNA priming, we tested the efficacy of adenovirus vaccine alone (NMRC-M3V-Ad-PfCA ) in a Phase 1 clinical trial. Methodology/Principal Findings: The regimen was a single intramuscular injection with two non-replicating human serotype 5 adenovectors encoding CSP and AMA1, respectively. One x 1010 particle units of each construct were combined prior to administration. The regimen was safe and well-tolerated. Four weeks later, 18 study subjects received P. falciparum CHMI administered by mosquito bite. None were fully protected although one showed delayed onset of parasitemia. Antibody responses were low, with geometric mean CSP ELISA titer of 381 (range < 50–1626) and AMA1 ELISA of 4.95 µg/mL (range 0.2–38). Summed ex vivo IFN-? ELISpot responses to overlapping peptides were robust, with geometric mean spot forming cells/million peripheral blood mononuclear cells [sfc/m] for CSP of 273 (range 38–2550) and for AMA1 of 1303 (range 435–4594). CD4+ and CD8+ T cell IFN-? responses to CSP were positive by flow cytometry in 25% and 56% of the research subjects, respectively, and to AMA1 in 94% and 100%, respectively. Significance: In contrast to DNA/Ad, Ad alone did not protect against CHMI despite inducing broad, cell-mediated immunity, indicating that DNA priming is required for protection by the adenovirus-vectored vaccine. ClinicalTrials.gov Identifier: NCT00392015. PMID:23899517

  6. Expanding integrated vector management to promote healthy environments

    PubMed Central

    Lizzi, Karina M.; Qualls, Whitney A.; Brown, Scott C.; Beier, John C.

    2014-01-01

    Integrated Vector Management (IVM) strategies are intended to protect communities from pathogen transmission by arthropods. These strategies target multiple vectors and different ecological and socioeconomic settings, but the aggregate benefits of IVM are limited by the narrow focus of its approach; IVM strategies only aim to control arthropod vectors. We argue that IVM should encompass environmental modifications at early stages, for instance, infrastructural development and sanitation services, to regulate not only vectors but also nuisance-biting arthropods. An additional focus on nuisance-biting arthropods will improve public health, quality of life, and minimize social disparity issues fostered by pests. Optimally, IVM could incorporate environmental awareness and promotion of control methods in order to proactively reduce threats of serious pest situations. PMID:25028090

  7. Insecticide resistance in disease vectors from Mayotte: an opportunity for integrated vector management

    PubMed Central

    2014-01-01

    Background Mayotte, a small island in the Indian Ocean, has been affected for many years by vector-borne diseases. Malaria, Bancroftian filariasis, dengue, chikungunya and Rift Valley fever have circulated or still circulate on the island. They are all transmitted by Culicidae mosquitoes. To limit the impact of these diseases on human health, vector control has been implemented for more than 60 years on Mayotte. In this study, we assessed the resistance levels of four major vector species (Anopheles gambiae, Culex pipiens quinquefasciatus, Aedes aegypti and Aedes albopictus) to two types of insecticides: i) the locally currently-used insecticides (organophosphates, pyrethroids) and ii) alternative molecules that are promising for vector control and come from different insecticide families (bacterial toxins or insect growth regulators). When some resistance was found to one of these insecticides, we characterized the mechanisms involved. Methods Larval and adult bioassays were used to evaluate the level of resistance. When resistance was found, we tested for the presence of metabolic resistance through detoxifying enzyme activity assays, or for target-site mutations through molecular identification of known resistance alleles. Results Resistance to currently-used insecticides varied greatly between the four vector species. While no resistance to any insecticides was found in the two Aedes species, bioassays confirmed multiple resistance in Cx. p. quinquefasciatus (temephos: ~ 20 fold and deltamethrin: only 10% mortality after 24 hours). In An. gambiae, resistance was scarce: only a moderate resistance to temephos was found (~5 fold). This resistance appears to be due only to carboxyl-esterase overexpression and not to target modification. Finally, and comfortingly, none of the four species showed resistance to any of the new insecticides. Conclusions The low resistance observed in Mayotte’s main disease vectors is particularly interesting, because it leaves a range of tools useable by vector control services. Together with the relative isolation of the island (thus limited immigration of mosquitoes), it provides us with a unique place to implement an integrated vector management plan, including all the good practices learned from previous experiences. PMID:24984704

  8. Cliffordtori and unbiased vectors

    E-print Network

    Ole Andersson; Ingemar Bengtsson

    2015-06-30

    The existence problem for mutually unbiased bases is an unsolved problem in quantum information theory. A related question is whether every pair of bases admits vectors that are unbiased to both. Mathematically this translates to the question whether two Lagrangian Clifford tori intersect, and a body of results exists concerning it. These (deep!) results are however rather weak when viewed from the point of view of the first problem. We make a detailed study of how the intersections behave in the simplest non-trivial case, that of complex projective 2-space (the qutrit), for which the set of Clifford tori can be usefully parametrized by the unistochastic subset of Birkhoff's polytope. An interesting picture emerges. A foray into higher dimensions is included.

  9. Chameleon Vector Bosons

    E-print Network

    A. E. Nelson; J. Walsh

    2008-02-06

    We show that for a force mediated by a vector particle coupled to a conserved U(1) charge, the apparent range and strength can depend on the size and density of the source, and the proximity to other sources. This "chameleon" effect is due to screening from a light charged scalar. Such screening can weaken astrophysical constraints on new gauge bosons. As an example we consider the constraints on chameleonic gauged B-L. We show that although Casimir measurements greatly constrain any B-L force much stronger than gravity with range longer than 0.1 microns, there remains an experimental window for a long range chameleonic B-L force. Such a force could be much stronger than gravity, and long or infinite range in vacuum, but have an effective range near the surface of the earth which is less than a micron.

  10. Chameleon vector bosons

    SciTech Connect

    Nelson, Ann E.

    2008-05-01

    We show that for a force mediated by a vector particle coupled to a conserved U(1) charge, the apparent range and strength can depend on the size and density of the source, and the proximity to other sources. This chameleon effect is due to screening from a light charged scalar. Such screening can weaken astrophysical constraints on new gauge bosons. As an example we consider the constraints on chameleonic gauged B-L. We show that although Casimir measurements greatly constrain any B-L force much stronger than gravity with range longer than 0.1 {mu}m, there remains an experimental window for a long-range chameleonic B-L force. Such a force could be much stronger than gravity, and long or infinite range in vacuum, but have an effective range near the surface of the earth which is less than a micron.

  11. Solar imaging vector magnetograph

    NASA Technical Reports Server (NTRS)

    Canfield, Richard C.

    1993-01-01

    This report describes an instrument which has been constructed at the University of Hawaii to make observations of the magnetic field in solar active regions. Detailed knowledge of active region magnetic structures is crucial to understanding many solar phenomena, because the magnetic field both defines the morphology of structures seen in the solar atmosphere and is the apparent energy source for solar flares. The new vector magnetograph was conceived in response to a perceived discrepancy between the capabilities of X ray imaging telescopes to be operating during the current solar maximum and those of existing magnetographs. There were no space-based magnetographs planned for this period; the existing ground-based instruments variously suffered from lack of sensitivity, poor time resolution, inadequate spatial resolution or unreliable sites. Yet the studies of flares and their relationship to the solar corona planned for the 1991-1994 maximum absolutely required high quality vector magnetic field measurements. By 'vector' measurements we mean that the observation attempts to deduce the complete strength and direction of the field at the measurement site, rather than just the line of sight component as obtained by a traditional longitudinal magnetograph. Knowledge of the vector field permits one to calculate photospheric electric currents, which might play a part in heating the corona, and to calculate energy stored in coronal magnetic fields as the result of such currents. Information about the strength and direction of magnetic fields in the solar atmosphere can be obtained in a number of ways, but quantitative data is best obtained by observing Zeeman-effect polarization in solar spectral lines. The technique requires measuring the complete state of polarization at one or more wavelengths within a magnetically sensitive line of the solar spectrum. This measurement must be done for each independent spatial point for which one wants magnetic field data. All the measurements need to be done in a time short compared to the time scale for changes of the solar features being observed. Were it possible, one would want to record all the needed data simultaneously, since temporal variation of atmospheric seeing degrades both the image and the polarization sensitivity. Since the measurements must span four dimensions, two spatial plus polarization and wavelength, we had some freedom to design the instrument to favor some dimensions over others in terms of simultaneity. Our earlier instrument, the Haleakala Stokes Polarimeter, records a range of wavelengths spanning two spectral lines in each reading, but requires two seconds to determine the polarization state and obtains spatial information only by assembling a long sequence of measurements at single locations on the sun. The new instrument sacrifices spectral detail and accuracy in favor of greatly improved imaging characteristics. The scientific goals for this instrument were to measure surface magnetic fields with enough accuracy to permit calculations of photospheric currents, but with a field of view covering an entire typical active region, high spatial resolution, and a fast enough temporal cadence for detecting flare-associated changes in magnetic structures.

  12. The Insect Microbiome Modulates Vector Competence for Arboviruses

    PubMed Central

    Jupatanakul, Natapong; Sim, Shuzhen; Dimopoulos, George

    2014-01-01

    Diseases caused by arthropod-borne viruses (arboviruses), such as Dengue, West Nile, and Chikungunya, constitute a major global health burden and are increasing in incidence and geographic range. The natural microbiota of insect vectors influences various aspects of host biology, such as nutrition, reproduction, metabolism, and immunity, and recent studies have highlighted the ability of insect-associated bacteria to reduce vector competence for arboviruses and other pathogens. This reduction can occur through mechanisms, such as immune response activation, resource competition, or the production of anti-viral molecules. Studying the interactions between insect vectors and their microbiota is an important step toward developing alternative strategies for arbovirus transmission control. PMID:25393895

  13. VECTUM. Irregular 2D Velocity Vector Field Plotting Package

    SciTech Connect

    McClurg, F.R.; Mousseau, V.A.

    1992-05-04

    VECTUM is a NCAR Graphics based package, for generating a plot of an irregular 2D velocity vector field. The program reads an ASCII database of x, y, u, v, data pairs and produces a plot in Computer Graphics Metafile (CGM) format. The program also uses an ASCII parameter file for controlling annotation details such as the plot title, arrowhead style, scale of vectors, windowing, etc. Simple geometry (i.e. lines, arcs, splines) can be defined to be included with the velocity vectors. NCAR Graphics drivers can be used to display the CGM file into PostScript, HPGL, HDF, etc, output.

  14. Development of an AIDS vaccine using Sendai virus vectors.

    PubMed

    Ishii, Hiroshi; Matano, Tetsuro

    2015-11-01

    Development of an effective AIDS vaccine is crucial for the control of global human immunodeficiency virus type 1 (HIV-1) prevalence. We have developed a novel AIDS vaccine using a Sendai virus (SeV) vector and investigated its efficacy in a macaque AIDS model of simian immunodeficiency virus (SIV) infection. Its immunogenicity and protective efficacy have been shown, indicating that the SeV vector is a promising delivery tool for AIDS vaccines. Here, we describe the potential of SeV vector as a vaccine antigen delivery tool to induce effective immune responses against HIV-1 infection. PMID:26232346

  15. ARTICLE IN PRESS YJMAA:13032 Please cite this article in press as: H.-M. Wei et al., An epidemic model of a vector-borne disease with direct transmission and time delay, J.

    E-print Network

    Martcheva, Maia

    is the most prevalent vector-borne disease whose vectors are the mosquitoes. The mosquitoes are vectors (Marfin and Gubler [2]) or reemerged as a significant health problem after being put under control

  16. Execution of vector operations for Intel 860

    SciTech Connect

    Khaletskii, D.A.

    1995-03-01

    When designing a portable setup compiler from the C[] language, the compiler setup problem is solved for various SIMD computers. A vector and vector operations are defined in C[]. A map of vector operations is trivial for computers with vector registers. Some problems appear when mapping them to computers without vector registers. It is shown how to effectively perform vector operations for the 1860 microcomputer as an example of one without vector registers.

  17. Vectors on the Basketball Court

    ERIC Educational Resources Information Center

    Bergman, Daniel

    2010-01-01

    An Idea Bank published in the April/May 2009 issue of "The Science Teacher" describes an experiential physics lesson on vectors and vector addition (Brown 2009). Like its football predecessor, the basketball-based investigation presented in this Idea Bank addresses National Science Education Standards Content B, Physical Science, 9-12 (NRC 1996)…

  18. Canine vector-borne diseases in Brazil

    PubMed Central

    Dantas-Torres, Filipe

    2008-01-01

    Canine vector-borne diseases (CVBDs) are highly prevalent in Brazil and represent a challenge to veterinarians and public health workers, since some diseases are of great zoonotic potential. Dogs are affected by many protozoa (e.g., Babesia vogeli, Leishmania infantum, and Trypanosoma cruzi), bacteria (e.g., Anaplasma platys and Ehrlichia canis), and helminths (e.g., Dirofilaria immitis and Dipylidium caninum) that are transmitted by a diverse range of arthropod vectors, including ticks, fleas, lice, triatomines, mosquitoes, tabanids, and phlebotomine sand flies. This article focuses on several aspects (etiology, transmission, distribution, prevalence, risk factors, diagnosis, control, prevention, and public health significance) of CVBDs in Brazil and discusses research gaps to be addressed in future studies. PMID:18691408

  19. Segmentation of discrete vector fields.

    PubMed

    Li, Hongyu; Chen, Wenbin; Shen, I-Fan

    2006-01-01

    In this paper, we propose an approach for 2D discrete vector field segmentation based on the Green function and normalized cut. The method is inspired by discrete Hodge Decomposition such that a discrete vector field can be broken down into three simpler components, namely, curl-free, divergence-free, and harmonic components. We show that the Green Function Method (GFM) can be used to approximate the curl-free and the divergence-free components to achieve our goal of the vector field segmentation. The final segmentation curves that represent the boundaries of the influence region of singularities are obtained from the optimal vector field segmentations. These curves are composed of piecewise smooth contours or streamlines. Our method is applicable to both linear and nonlinear discrete vector fields. Experiments show that the segmentations obtained using our approach essentially agree with human perceptual judgement. PMID:16640243

  20. A neural support vector machine.

    PubMed

    Jändel, Magnus

    2010-06-01

    Support vector machines are state-of-the-art pattern recognition algorithms that are well founded in optimization and generalization theory but not obviously applicable to the brain. This paper presents Bio-SVM, a biologically feasible support vector machine. An unstable associative memory oscillates between support vectors and interacts with a feed-forward classification pathway. Kernel neurons blend support vectors and sensory input. Downstream temporal integration generates the classification. Instant learning of surprising events and off-line tuning of support vector weights trains the system. Emotion-based learning, forgetting trivia, sleep and brain oscillations are phenomena that agree with the Bio-SVM model. A mapping to the olfactory system is suggested. PMID:20092978

  1. Community Participation in Chagas Disease Vector Surveillance: Systematic Review

    PubMed Central

    Abad-Franch, Fernando; Vega, M. Celeste; Rolón, Miriam S.; Santos, Walter S.; Rojas de Arias, Antonieta

    2011-01-01

    Background Vector control has substantially reduced Chagas disease (ChD) incidence. However, transmission by household-reinfesting triatomines persists, suggesting that entomological surveillance should play a crucial role in the long-term interruption of transmission. Yet, infestation foci become smaller and harder to detect as vector control proceeds, and highly sensitive surveillance methods are needed. Community participation (CP) and vector-detection devices (VDDs) are both thought to enhance surveillance, but this remains to be thoroughly assessed. Methodology/Principal Findings We searched Medline, Web of Knowledge, Scopus, LILACS, SciELO, the bibliographies of retrieved studies, and our own records. Data from studies describing vector control and/or surveillance interventions were extracted by two reviewers. Outcomes of primary interest included changes in infestation rates and the detection of infestation/reinfestation foci. Most results likely depended on study- and site-specific conditions, precluding meta-analysis, but we re-analysed data from studies comparing vector control and detection methods whenever possible. Results confirm that professional, insecticide-based vector control is highly effective, but also show that reinfestation by native triatomines is common and widespread across Latin America. Bug notification by householders (the simplest CP-based strategy) significantly boosts vector detection probabilities; in comparison, both active searches and VDDs perform poorly, although they might in some cases complement each other. Conclusions/Significance CP should become a strategic component of ChD surveillance, but only professional insecticide spraying seems consistently effective at eliminating infestation foci. Involvement of stakeholders at all process stages, from planning to evaluation, would probably enhance such CP-based strategies. PMID:21713022

  2. Use of Insecticide-Treated House Screens to Reduce Infestations of Dengue Virus Vectors, Mexico

    PubMed Central

    Manrique-Saide, Pablo; Che-Mendoza, Azael; Barrera-Perez, Mario; Guillermo-May, Guillermo; Herrera-Bojorquez, Josue; Dzul-Manzanilla, Felipe; Gutierrez-Castro, Cipriano; Lenhart, Audrey; Vazquez-Prokopec, Gonzalo; Sommerfeld, Johannes; McCall, Philip J.; Kroeger, Axel

    2015-01-01

    Dengue prevention efforts rely on control of virus vectors. We investigated use of insecticide-treated screens permanently affixed to windows and doors in Mexico and found that the screens significantly reduced infestations of Aedes aegypti mosquitoes in treated houses. Our findings demonstrate the value of this method for dengue virus vector control. PMID:25625483

  3. Use of insecticide-treated house screens to reduce infestations of dengue virus vectors, Mexico.

    PubMed

    Manrique-Saide, Pablo; Che-Mendoza, Azael; Barrera-Perez, Mario; Guillermo-May, Guillermo; Herrera-Bojorquez, Josue; Dzul-Manzanilla, Felipe; Gutierrez-Castro, Cipriano; Lenhart, Audrey; Vazquez-Prokopec, Gonzalo; Sommerfeld, Johannes; McCall, Philip J; Kroeger, Axel; Arredondo-Jimenez, Juan I

    2015-02-01

    Dengue prevention efforts rely on control of virus vectors. We investigated use of insecticide-treated screens permanently affixed to windows and doors in Mexico and found that the screens significantly reduced infestations of Aedes aegypti mosquitoes in treated houses. Our findings demonstrate the value of this method for dengue virus vector control. PMID:25625483

  4. Vector Network Analysis

    Energy Science and Technology Software Center (ESTSC)

    1997-10-20

    Vector network analyzers are a convenient way to measure scattering parameters of a variety of microwave devices. However, these instruments, unlike oscilloscopes for example, require a relatively high degree of user knowledge and expertise. Due to the complexity of the instrument and of the calibration process, there are many ways in which an incorrect measurement may be produced. The Microwave Project, which is part of Sandia National Laboratories Primary Standards Laboratory, routinely uses check standardsmore »to verify that the network analyzer is operating properly. In the past, these measurements were recorded manually and, sometimes, interpretation of the results was problematic. To aid our measurement assurance process, a software program was developed to automatically measure a check standard and compare the new measurements with an historical database of measurements of the same device. The program acquires new measurement data from selected check standards, plots the new data against the mean and standard deviation of prior data for the same check standard, and updates the database files for the check standard. The program is entirely menu-driven requiring little additional work by the user.« less

  5. Vector Color Transparency

    E-print Network

    W. R. Greenberg; G. A. Miller

    1993-09-20

    Color transparency (CT) in high momentum transfer $(e,e' \\vec p)$ reactions is explored. The spin of the proton and photon are treated explicitly, hence the name ``Vector CT". The Dirac distorted wave impulse approximation is used as a starting point; then CT effects are embedded. A hadronic basis is used to describe the struck proton as a wavepacket of physical baryon resonances. The effects of the wavepacket expansion on the normal component of the ejectile polarization, which vanishes in the limit of full CT, are investigated. This formalism is also applied to study CT effects in total cross sections, individual separated nuclear response functions, Fermi motion of the initial nucleon, non-zero size of the initial wavepacket and the effects of relativistic lower components. We show that including CT reduces the violations of current conservation (CC), a typical problem in calculations of this kind. The energy dependence of the normal polarization in $(e,e' \\vec p)$ reactions is found to be slow. However, a measurement of the normal transverse response in a heavy nucleus, such as $^{208}Pb$ seems to afford the opportunity to see CT at quite low momentum transfers. The effects of Fermi motion are investigated, and choosing the momentum of the struck nucleon to be large leads to significant violations of CC.

  6. Disrupting the transmission of a vector-borne plant pathogen.

    PubMed

    Killiny, Nabil; Rashed, Arash; Almeida, Rodrigo P P

    2012-02-01

    Approaches to control vector-borne diseases rarely focus on the interface between vector and microbial pathogen, but strategies aimed at disrupting the interactions required for transmission may lead to reductions in disease spread. We tested if the vector transmission of the plant-pathogenic bacterium Xylella fastidiosa was affected by three groups of molecules: lectins, carbohydrates, and antibodies. Although not comprehensively characterized, it is known that X. fastidiosa adhesins bind to carbohydrates, and that these interactions are important for initial cell attachment to vectors, which is required for bacterial transmission from host to host. Lectins with affinity to substrates expected to occur on the cuticular surface of vectors colonized by X. fastidiosa, such as wheat germ agglutinin, resulted in statistically significant reductions in transmission rate, as did carbohydrates with N-acetylglucosamine residues. Presumably, lectins bound to receptors on the vector required for cell adhesion/colonization, while carbohydrate-saturated adhesins on X. fastidiosa's cell surface. Furthermore, antibodies against X. fastidiosa whole cells, gum, and afimbrial adhesins also resulted in transmission blockage. However, no treatment resulted in the complete abolishment of transmission, suggesting that this is a complex biological process. This work illustrates the potential to block the transmission of vector-borne pathogens without directly affecting either organism. PMID:22101059

  7. Improving the Quality of Host Country Ethical Oversight of International Research: The Use of a Collaborative 'Pre-Review' Mechanism for a Study of Fexinidazole for Human African Trypanosomiasis.

    PubMed

    Coleman, Carl H; Ardiot, Chantal; Blesson, Séverine; Bonnin, Yves; Bompart, Francois; Colonna, Pierre; Dhai, Ames; Ecuru, Julius; Edielu, Andrew; Hervé, Christian; Hirsch, François; Kouyaté, Bocar; Mamzer-Bruneel, Marie-France; Maoundé, Dionko; Martinent, Eric; Ntsiba, Honoré; Pelé, Gérard; Quéva, Gilles; Reinmund, Marie-Christine; Sarr, Samba Cor; Sepou, Abdoulaye; Tarral, Antoine; Tetimian, Djetodjide; Valverde, Olaf; Van Nieuwenhove, Simon; Strub-Wourgaft, Nathalie

    2015-12-01

    Developing countries face numerous barriers to conducting effective and efficient ethics reviews of international collaborative research. In addition to potentially overlooking important scientific and ethical considerations, inadequate or insufficiently trained ethics committees may insist on unwarranted changes to protocols that can impair a study's scientific or ethical validity. Moreover, poorly functioning review systems can impose substantial delays on the commencement of research, which needlessly undermine the development of new interventions for urgent medical needs. In response to these concerns, the Drugs for Neglected Diseases Initiative (DNDi), an independent nonprofit organization founded by a coalition of public sector and international organizations, developed a mechanism to facilitate more effective and efficient host country ethics review for a study of the use of fexinidazole for the treatment of late stage African Trypanosomiasis (HAT). The project involved the implementation of a novel 'pre-review' process of ethical oversight, conducted by an ad hoc committee of ethics committee representatives from African and European countries, in collaboration with internationally recognized scientific experts. This article examines the process and outcomes of this collaborative process. PMID:25039421

  8. Vector volume and black holes

    NASA Astrophysics Data System (ADS)

    Ballik, William; Lake, Kayll

    2013-11-01

    By examining the rate of growth of an invariant volume V of some spacetime region along a divergence-free vector field v?, we introduce the concept of a “vector volume” Vv. This volume can be defined in various equivalent ways. For example, it can be given as dV(?)/d?, where v???=d/d? and ? is a parameter distance along the integral curve of v. Equivalently, it can be defined as ?v?d??, where d?? is the directed surface element. We find that this volume is especially useful for the description of black holes, but it can be used in other contexts as well. Moreover, this volume has several properties of interest. Among these is the fact that the vector volume is linear with respect to the the choice of vector v?. As a result, for example, in stationary axially symmetric spacetimes with timelike Killing vectors t? and axially symmetric Killing vectors ??, the vector volume of an axially symmetric region with respect to the vector t?+??? is equal for any value of ?, a consequence of the additional result that ?? does not contribute to Vv. Perhaps of most interest is the fact that in Kerr-Schild spacetimes the volume element for the full spacetime is equal to that of the background spacetime. We discuss different ways of using the vector volume to define volumes for black holes. Finally, we relate our work to the recent widespread thermodynamically motivated study of the “volumes” of black holes associated with nonzero values of the cosmological constant ?.

  9. Emerging Vector-Borne Diseases – Incidence through Vectors

    PubMed Central

    Savi?, Sara; Vidi?, Branka; Grgi?, Zivoslav; Potkonjak, Aleksandar; Spasojevic, Ljubica

    2014-01-01

    Vector-borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowadays, in intercontinental countries, there is a struggle with emerging diseases, which have found their way to appear through vectors. Vector-borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens, and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector-borne infectious diseases and disease outbreaks. It could affect the range and population of pathogens, host and vectors, transmission season, etc. Reliable surveillance for diseases that are most likely to emerge is required. Canine vector-borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, and leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fundamental role at primarily prevention and then treatment of vector-borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases. During a 4-year period, from 2009 to 2013, a total number of 551 dog samples were analyzed for vector-borne diseases (borreliosis, babesiosis, ehrlichiosis, anaplasmosis, dirofilariosis, and leishmaniasis) in routine laboratory work. The analysis was done by serological tests – ELISA for borreliosis, dirofilariosis, and leishmaniasis, modified Knott test for dirofilariosis, and blood smear for babesiosis, ehrlichiosis, and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on average more then half of the samples brought to the laboratory to analysis for different infectious diseases are analyzed for vector-borne diseases. In the region of Vojvodina (northern part of Serbia), the following vector-borne infectious diseases have been found in dogs so far borreliosis, babesiosis, dirofilariosis, leishmaniasis, and anaplasmosis. PMID:25520951

  10. RNAi in Arthropods: Insight into the Machinery and Applications for Understanding the Pathogen-Vector Interface

    PubMed Central

    Barnard, Annette-Christi; Nijhof, Ard M.; Fick, Wilma; Stutzer, Christian; Maritz-Olivier, Christine

    2012-01-01

    The availability of genome sequencing data in combination with knowledge of expressed genes via transcriptome and proteome data has greatly advanced our understanding of arthropod vectors of disease. Not only have we gained insight into vector biology, but also into their respective vector-pathogen interactions. By combining the strengths of postgenomic databases and reverse genetic approaches such as RNAi, the numbers of available drug and vaccine targets, as well as number of transgenes for subsequent transgenic or paratransgenic approaches, have expanded. These are now paving the way for in-field control strategies of vectors and their pathogens. Basic scientific questions, such as understanding the basic components of the vector RNAi machinery, is vital, as this allows for the transfer of basic RNAi machinery components into RNAi-deficient vectors, thereby expanding the genetic toolbox of these RNAi-deficient vectors and pathogens. In this review, we focus on the current knowledge of arthropod vector RNAi machinery and the impact of RNAi on understanding vector biology and vector-pathogen interactions for which vector genomic data is available on VectorBase. PMID:24705082

  11. A stable RNA virus-based vector for citrus trees

    SciTech Connect

    Folimonov, Alexey S.; Folimonova, Svetlana Y.; Bar-Joseph, Moshe; Dawson, William O.

    2007-11-10

    Virus-based vectors are important tools in plant molecular biology and plant genomics. A number of vectors based on viruses that infect herbaceous plants are in use for expression or silencing of genes in plants as well as screening unknown sequences for function. Yet there is a need for useful virus-based vectors for woody plants, which demand much greater stability because of the longer time required for systemic infection and analysis. We examined several strategies to develop a Citrus tristeza virus (CTV)-based vector for transient expression of foreign genes in citrus trees using a green fluorescent protein (GFP) as a reporter. These strategies included substitution of the p13 open reading frame (ORF) by the ORF of GFP, construction of a self-processing fusion of GFP in-frame with the major coat protein (CP), or expression of the GFP ORF as an extra gene from a subgenomic (sg) mRNA controlled either by a duplicated CTV CP sgRNA controller element (CE) or an introduced heterologous CE of Beet yellows virus. Engineered vector constructs were examined for replication, encapsidation, GFP expression during multiple passages in protoplasts, and for their ability to infect, move, express GFP, and be maintained in citrus plants. The most successful vectors based on the 'add-a-gene' strategy have been unusually stable, continuing to produce GFP fluorescence after more than 4 years in citrus trees.

  12. Wheel speed management control system for spacecraft

    NASA Technical Reports Server (NTRS)

    Goodzeit, Neil E. (Inventor); Linder, David M. (Inventor)

    1991-01-01

    A spacecraft attitude control system uses at least four reaction wheels. In order to minimize reaction wheel speed and therefore power, a wheel speed management system is provided. The management system monitors the wheel speeds and generates a wheel speed error vector. The error vector is integrated, and the error vector and its integral are combined to form a correction vector. The correction vector is summed with the attitude control torque command signals for driving the reaction wheels.

  13. Evaluation of attractive toxic sugar bait (ATSB)-barrier for control of vector and nuisance mosquitoes and its effect on non-target organisms in sub-tropical environments in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the efficacy of attractive toxic sugar baits (ATSB) in the laboratory and the field with the Environmental Protection Agency exempt active ingredient eugenol against vector and nuisance mosquitoes. In the laboratory, eugenol combined in attractive sugar bait (ASB) solution provided high...

  14. Incremental learning for ?-Support Vector Regression.

    PubMed

    Gu, Bin; Sheng, Victor S; Wang, Zhijie; Ho, Derek; Osman, Said; Li, Shuo

    2015-07-01

    The ?-Support Vector Regression (?-SVR) is an effective regression learning algorithm, which has the advantage of using a parameter ? on controlling the number of support vectors and adjusting the width of the tube automatically. However, compared to ?-Support Vector Classification (?-SVC) (Schölkopf et al., 2000), ?-SVR introduces an additional linear term into its objective function. Thus, directly applying the accurate on-line ?-SVC algorithm (AONSVM) to ?-SVR will not generate an effective initial solution. It is the main challenge to design an incremental ?-SVR learning algorithm. To overcome this challenge, we propose a special procedure called initial adjustments in this paper. This procedure adjusts the weights of ?-SVC based on the Karush-Kuhn-Tucker (KKT) conditions to prepare an initial solution for the incremental learning. Combining the initial adjustments with the two steps of AONSVM produces an exact and effective incremental ?-SVR learning algorithm (INSVR). Theoretical analysis has proven the existence of the three key inverse matrices, which are the cornerstones of the three steps of INSVR (including the initial adjustments), respectively. The experiments on benchmark datasets demonstrate that INSVR can avoid the infeasible updating paths as far as possible, and successfully converges to the optimal solution. The results also show that INSVR is faster than batch ?-SVR algorithms with both cold and warm starts. PMID:25933108

  15. Support Vector Machines in Bioinformatics

    E-print Network

    Spang, Rainer

    Support Vector Machines 29 4 Linear Classi#12;ers 31 4.1 The Optimal Separating Hyperplane (OSH) . . . . . . . . . . . . . . . . 32 4.2 OSH for Linear Non-Separable Datasets . . . . . . . . . . . . . . . . . . 40 4.3 Adaption

  16. Support Vector Machines in Bioinformatics

    E-print Network

    Spang, Rainer

    Support Vector Machines 29 4 Linear Classifiers 31 4.1 The Optimal Separating Hyperplane (OSH) . . . . . . . . . . . . . . . . 32 4.2 OSH for Linear Non-Separable Datasets . . . . . . . . . . . . . . . . . . 40 4.3 Adaption

  17. Uncertainty principles and vector quantization

    E-print Network

    Vershynin, Roman

    1 Uncertainty principles and vector quantization Yurii Lyubarskii and Roman Vershynin Abstract of the state-of-the-art of quantization prior to 1998 as well as outline of its nu- merous applications can

  18. Standardizing Visual Control Devices for Tsetse Flies: East African Species Glossina swynnertoni

    PubMed Central

    Mramba, Furaha; Oloo, Francis; Byamungu, Mechtilda; Kröber, Thomas; McMullin, Andrew; Mihok, Steve; Guerin, Patrick M.

    2013-01-01

    Background Here we set out to standardize long-lasting, visually-attractive devices for Glossina swynnertoni, a vector of both human and animal trypanosomiasis in open savannah in Tanzania and Kenya, and in neighbouring conservation areas used by pastoralists. The goal was to determine the most practical device/material that would induce the strongest landing response in G. swynnertoni for use in area-wide population suppression of this fly with insecticide-impregnated devices. Methods and Findings Trials were conducted in wet and dry seasons in the Serengeti and Maasai Mara to measure the performance of traps and targets of different sizes and colours, with and without chemical baits, at different population densities and under different environmental conditions. Adhesive film was used as a simple enumerator at these remote locations to compare trapping efficiencies of devices. Independent of season or presence of chemical baits, targets in phthalogen blue or turquoise blue cloth with adhesive film were the best devices for capturing G. swynnertoni in all situations, catching up to 19 times more flies than pyramidal traps. Baiting with chemicals did not affect the relative performance of devices. Fly landings were two times higher on 1 m2 blue-black targets as on pyramidal traps when equivalent areas of both were covered with adhesive film. Landings on 1 m2 blue-black targets were compared to those on smaller phthalogen blue 0.5 m2 all-blue or blue-black-blue cloth targets, and to landings on all-blue plastic 0.32–0.47 m2 leg panels painted in phthalogen blue. These smaller targets and leg panels captured equivalent numbers of G. swynnertoni per unit area as bigger targets. Conclusions Leg panels and 0.5 m2 cloth targets show promise as cost effective devices for management of G. swynnertoni as they can be used for both control (insecticide-impregnated cloth) and for sampling (rigid plastic with insect glue or adhesive film) of populations. PMID:23469299

  19. Vectorization of linear discrete filtering algorithms

    NASA Technical Reports Server (NTRS)

    Schiess, J. R.

    1977-01-01

    Linear filters, including the conventional Kalman filter and versions of square root filters devised by Potter and Carlson, are studied for potential application on streaming computers. The square root filters are known to maintain a positive definite covariance matrix in cases in which the Kalman filter diverges due to ill-conditioning of the matrix. Vectorization of the filters is discussed, and comparisons are made of the number of operations and storage locations required by each filter. The Carlson filter is shown to be the most efficient of the filters on the Control Data STAR-100 computer.

  20. Study of The Vector Product using Three Dimensions Vector Card of Engineering in Pathumwan Institute of Technology

    NASA Astrophysics Data System (ADS)

    Mueanploy, Wannapa

    2015-06-01

    The objective of this research was to offer the way to improve engineering students in Physics topic of vector product. The sampling of this research was the engineering students at Pathumwan Institute of Technology during the first semester of academic year 2013. 1) Select 120 students by random sampling are asked to fill in a satisfaction questionnaire scale, to select size of three dimensions vector card in order to apply in the classroom. 2) Select 60 students by random sampling to do achievement test and take the test to be used in the classroom. The methods used in analysis of achievement test by the Kuder-Richardson Method (KR- 20). The results show that 12 items of achievement test are appropriate to be applied in the classroom. The achievement test gets Difficulty (P) = 0.40-0.67, Discrimination = 0.33-0.73 and Reliability (r) = 0.70.The experimental in the classroom. 3) Select 60 students by random sampling divide into two groups; group one (the controlled group) with 30 students was chosen to study in the vector product lesson by the regular teaching method. Group two (the experimental group) with 30 students was chosen to learn the vector product lesson with three dimensions vector card. 4) Analyzed data between the controlled group and the experimental group, the result showed that experimental group got higher achievement test than the controlled group significant at .01 level.