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Objective To study dengue vector breeding patterns under a variety of conditions in public and private spaces; to explore the ecological, biological and social (eco-bio-social) factors involved in vector breeding and viral transmission, and to define the main implications for vector control. Methods In each of six Asian cities or periurban areas, a team randomly selected urban clusters for conducting standardized household surveys, neighbourhood background surveys and entomological surveys. They collected information on vector breeding sites, people's knowledge, attitudes and practices surrounding dengue, and the characteristics of the study areas. AII premises were inspected; larval indices were used to quantify vector breeding sites, and pupal counts were used to identify productive water container types and as a proxy measure for adult vector abundance. Findings The most productive vector breeding sites were outdoor water containers, particularly if uncovered, beneath shrubbery and unused for at least one week. Peridomestic and intradomestic areas were much more important for pupal production than commercial and public spaces other than schools and religious facilities. A complex but non-significant association was found between water supply and pupal counts, and lack of waste disposal services was associated with higher vector abundance in only one site. Greater knowledge about dengue and its transmission was associated with lower mosquito breeding and production. Vector control measures (mainly larviciding in one site) substantially reduced larval and pupal counts and 'pushed' mosquito breeding to alternative containers. Conclusion Vector breeding and the production of adult Aedes aegypti are influenced by a complex interplay of factors. Thus, to achieve effective vector management, a public health response beyond routine larviciding or focal spraying is essential. Objectif Etudier les schemas de reproduction des vecteurs de la dengue dans diverses conditions et dans des espaces publics et prives, rechercher les facteurs ecologiques, biologiques et sociaux impliques dans la reproduction de ces vecteurs et la transmission virale et determiner les principales implications pour la lutte antivectorielle. Methodes Dans six grandes villes ou zones periurbaines d'Asie, une equipe a selectionne au hasard des groupes urbains pour mener des enquetes aupres des rnenages standardisees, des enquetes de voisinage et des enquetes entomologiques. Les equipes ont recueilli des informations sur les sites de reproduction des vecteurs, les connaissances des habitants, les attitudes et les pratiques a propos de la dengue et les caracteristiques des zones etudiees. Tous les lieux ont ete inspectes; les equipes ont utilise les indices larvaires pour evaluer sur le plan quantitatif les sites de reproduction vectorielle et le decompte des pupes pour identifier les types d'objets renfermant de l'eau les plus productifs et pour servir de mesure indirecte de l'abondance des vecteurs adultes. Resultats Les sites de reproduction les plus productifs etaient les objets renfermant de I'eau situes a I'exterieur, en particulier lorsqu'ils etaient depourvus de couvercle, sous des broussailles et inutilises pendant au moins une semaine. Les zones peridornestiques et intradornestiques jouaient un role beaucoup plus important dans la production de pupes que les espaces commerciaux et publics autres que les ecoles et les edifices religieux. Une association complexe, mais non significative, a ete relevee entre l'approvisionnement en eau et le nombre de pupes decomptees et on a constate un lien entre le manque de services d'elimination des dechets et une plus grande abondance des vecteurs sur un site seulement. La presence de meilleures connaissances sur la dengue et sa transmission chez les habitants etait egalement associee une reproduction et a une production plus limitees des vecteurs. Les mesures de lutte antivectorielle (principalement I'application de larvicide sur le site) ont permis de reduire substantiellement les nin de larves et de pupes eta <> la reproduction des moustiques vers d'autres recipients. Conclusion Un ensemble interactif complexe de facteurs influe sur la reproduction et la production de moustiques Aedes aegypti adultes. Ainsi, pour gerer efficacement les populations vectorielles, une reponse de sante publique globale, allant au-dela des traitements larvicides de routine ou de la pulverisation focale, est indispensable. Objetivo Estudiar las caracteristicas de la reproduccion del vector del dengue en diversas condiciones en espacios publicos y privados; investigar los aspectos ecologicos, biologicos y sociales (ecobiosociales) que intervienen en la reproduccion del vector y la transmision del virus, y determinar las principales implicaciones para la lucha antivectorial. Metodos En cada una de las seis zonas urbanas o periurbanas de Asia estudiadas, un equipo selecciono al azar conglomerados urbanos para realizar encuestas de hogares normalizadas, encuestas basales del vecindario y estudios entomologicos. Reunieron informacion sobre los criaderos de vectores, los conocimientos de la gente al respecto, las actitudes y practicas relacionadas con el dengue, y las caracteristicas de las zonas estudiadas. Se inspeccionaron todos los locales, y se usaron los indices larvarios para cuantificar los criaderos del vector, y el numero de pupas para distinguir el tipo de contenedores de agua productivos y como indicador sustitutivo de la abundancia de vectores adultos. Resultados Los criaderos de vectores mas productivos fueron los contenedores de agua situados al aire libre, sobre todo los que estaban sin cubrir o debajo de arbustos, y los que no habian sido utilizados por lo menos en una semana. Las areas peridomesticas e intradomesticas contribuian a la produccion de pupas mucho mas que los espacios comerciales y publicos, exceptuando las escuelas y los centros religiosos. Se observo una relacion compleja aunque no significativa entre el suministro de agua y el numero de pupas, y la falta de servicios de evacuacion de desechos se asocio a una mayor abundancia de vectores en un solo sitio. La posesion de mayores conocimientos sobre el dengue y su transmision se asocio a una menor reproduccion y produccion de'mosquitos. Las medidas de lucha antivectorial (principalmente la aplicacion de larvicidas en un sitio) lograron reducir sustancialmente el numero de larvas y pupas y los criaderos de mosquitos hacia otros contenedores. Conclusion La reproduccion del vector y la produccion de Aedes aegypti adulto dependen de una compleja interaccion de factores. En consecuencia, para lograr controlar eficazmente los vectores, es fundamental articular una respuesta de salud publica que no se limite a la aplicacion de larvicidas o el rociamiento localizado., Introduction Dengue, which is the fastest re-emerging arboviral disease in the world, imposes a heavy economic and health burden on countries, families and individual patients. (1,2) In the absence of [...]

Abstract Background There is an urgent need to protect children against dengue since this age group is particularly sensitive to the disease. Since dengue vectors are active mainly during the day, a potential target for control should be schools where children spend a considerable amount of their day. School uniforms are the cultural norm in most developing countries, worn throughout the day. We hypothesise that insecticide-treated school uniforms will reduce the incidence of dengue infection in school-aged children. Our objective is to determine the impact of impregnated school uniforms on dengue incidence. Methods A randomised controlled trial will be conducted in eastern Thailand in a group of schools with approximately 2,000 students aged 7–18 years. Pre-fabricated school uniforms will be commercially treated to ensure consistent, high-quality insecticide impregnation with permethrin. A double-blind, randomised, crossover trial at the school level will cover two dengue transmission seasons. Discussion Practical issues and plans concerning intervention implementation, evaluation, analysing and interpreting the data, and possible policy implications arising from the trial are discussed. Trial registration clinicaltrial.gov. Registration number: NCT01563640

Abstract Background Appropriate supervision, along with availability of an effective system for monitoring and evaluation, is a crucial requirement to guarantee sufficient coverage and quality of malaria vector control procedures. This study evaluated the efficacy of self-assessment practice as a possible innovative method towards achieving high coverage and excellent quality of larviciding operation in Iran. Methods The research was conducted on the randomly selected rural health centre of Kanmbel Soliman with 10 staff and 30 villages, in three main steps: (i) assessment of effectiveness of larviciding operations in the study areas before intervention through external assessment by a research team; (ii) self-assessment of larviciding operations (intervention) by staff every quarter for three rounds; and, (iii) determining the effectiveness of applying self-assessment of larviciding operations in the study areas. Two toolkits were used for self-assessment and external evaluation. The impact of self-assessment of larviciding operations was measured by two indicators: percentage of missed breeding habitats and cleaned breeding habitats among randomly selected breeding sites. Moreover, the correlation coefficients were measured between self-assessment measures and scores from external evaluation. The correlation coefficient and Mann Whitney test were used to analyse data. Results Following the utilization of self-assessment, the percentage of missed breeding habitats decreased significantly from 14.23% to 1.91% (P Before intervention, the results of self-assessment practice were compatible with external evaluation in 76.3% of 139 reviewed reports of self-assessment. After intervention, the findings of self-assessment and external evaluation were similar in the vast majority of reviewed reports (95%). Conclusion The self-assessment tool seems to be valid and reliable in improving effectiveness of larviciding operations. Furthermore, the result of self-assessment is more compatible with external evaluation results if it would be applied frequently. Therefore, it can be used as an alternative assessment technique in the evaluation of larviciding operations in addition to traditional assessment methods.

Abstract Background The highly pathogenic avian influenza (HPAI) H5N1 virus remains a worldwide threat to human and animal health, while the mechanisms explaining its epizootic emergence and re-emergence in poultry are largely unknown. Data from Thailand, a country that experienced significant epidemics in poultry and has recorded suspicious cases of HPAI on a daily basis since 2004, are used here to study the process of emergence. A spatial approach is employed to describe all HPAI H5N1 virus epizootics from 2004 to 2008 and to characterize the pattern of emergence: multiple independent introductions of the virus followed by moderate local spread vs. very rare emergences followed by strong local spread and rare long range diffusion jumps. Sites where epizootics originate (by foreign introduction, local persistence, or long range jump) were selected from those to which the disease subsequently spreads using a filter based on relative date and position. The spatial distribution of these selected foci was statistically analyzed, and to differentiate environmental factors from long range diffusion, we investigate the relationship of these foci with environmental exposure factors and with rearing characteristics. Results During each wave of epizootics, the temporal occurrence of cases did not show a temporal interruption of more than a week. All foci were globally clustered; i.e., more than 90% of cases had a previous case within a 10 km range and a 21 day period of time, showing a strong local spread. We were able to estimate 60 km as the maximum distance for the local farm to farm dissemination process. The remaining "emergent" cases have occurred randomly over Thailand and did not show specific location, clusters, or trends. We found that these foci are not statistically related to specific environmental conditions or land cover characteristics, and most of them may be interpreted as long range diffusion jumps due to commercial practices. Conclusion We conclude that only a few foci appear to have been at the origin of each HPAI epidemic wave, leading to the practical action that surveillance and control must focus on farm to farm transmission rather than on emergence or wild fauna.

A study was conducted to evaluate Photorhabdus insect-related protein (Pir) from Photorhabdus asymbiotica against dengue vectors. PirAB exhibited larvicidal activity against both Aedes aegypti and Aedes albopictus larvae bud did not affect the Mesocyclops thermocyclopoides predator.

Vector-borne diseases are a major health burden, yet factors affecting their spread are only partially understood. For example, microbial symbionts can impact mosquito reproduction, survival, and vectorial capacity, and hence affect disease transmission. Nonetheless, current knowledge of mosquito-associated microbial communities is limited. To characterize the bacterial and eukaryotic microbial communities of multiple vector species collected from different habitat types in disease endemic areas, we employed next-generation 454 pyrosequencing of 16S and 18S rRNA amplicon libraries, also known as metabarcoding. We investigated pooled whole adult mosquitoes of three medically important vectors, Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus, collected from different habitats across central Thailand where we previously characterized mosquito diversity. Our results indicate that diversity within the mosquito microbiota is low, with the majority of microbes assigned to one or a few taxa. Two of the most common eukaryotic and bacterial genera recovered (Ascogregarina and Wolbachia, respectively) are known mosquito endosymbionts with potentially parasitic and long evolutionary relationships with their hosts. Patterns of microbial composition and diversity appeared to differ by both vector species and habitat for a given species, although high variability between samples suggests a strong stochastic element to microbiota assembly. In general, our findings suggest that multiple factors, such as habitat condition and mosquito species identity, may influence overall microbial community composition, and thus provide a basis for further investigations into the interactions between vectors, their microbial communities, and human-impacted landscapes that may ultimately affect vector-borne disease risk. [ABSTRACT FROM AUTHOR]