Infection with Trypanosoma Cruzi Chagas and Characterization of Human Habitats of Triatoma Picturata (Usinger) in Western Mexico.

Chagas disease is one of the most important vector-borne diseases in Latin America. Triatoma picturata (Usinger), distributed in western Mexico, is one of the most important vectors of Trypanosoma cruzi Chagas. Knowing the type and materials used for building homes could lead to improved methods for controlling triatomines by focusing efforts on controlling every species of triatomine in its specific microhabitat. Houses in three studied localities of western Mexico that harbored T. picturata were characterized, as well as two entomological indices. Infestation Index values varied from 10.8% to 51.9% in the three localities, whereas Natural Infection Index values varied from 18.1% to 35.2%. Characteristics of houses invaded by T. picturata also varied. In Juan Gil Preciado, with the highest Entomological Index values, most houses were built of adobe walls with a roof of clay tiles and a dirt floor, and included the presence of domestic animals. Our data indicate that the potential risk of infection with T. cruzi differs markedly for inhabitants of the three studied localities, which demonstrates the importance of studying local populations of triatomines. Our study should contribute to decision-making regarding triatomine control efforts by providing profiles of houses that are more susceptible to triatomine invasion.

Entomovirological Surveillance in Schools: Are They a Source for Arboviral Diseases Transmission?

Surveillance and control activities for virus-transmitting mosquitoes have primarily focused on dwellings. There is little information about viral circulation in heavily trafficked places such as schools. We collected and analyzed data to assess the presence and prevalence of dengue, chikungunya, and Zika viruses in mosquitoes, and measured Aedes indices in schools in Medellín (Colombia) between 2016-2018. In 43.27% of 2632 visits we collected Aedes adults, creating 883 pools analyzed by RT-PCR. 14.27% of pools yielded positive for dengue or Zika (infection rates of 1.75-296.29 for Aedes aegypti). Ae. aegypti was more abundant and had a higher infection rate for all studied diseases. Aedes indices varied over time. There was no association between Aedes abundance and mosquito infection rates, but the latter did correlate with cases of arboviral disease and climate. Results suggest schools are important sources of arbovirus and health agencies should include these sites in surveillance programs; it is essential to know the source for arboviral diseases transmission and the identification of the most population groups exposed to these diseases to research and developing new strategies.

Evaluación de índices entomológicos mediante herramientas electrónicas en Villavicencio, Meta, Colombia / Evaluation of entomological indices with electronic tools in Villavicencio, Meta, Colombia

Objetivo: Determinar la eficacia de dos herramientas electrónicas en el levantamiento de índices aédicos en la ciudad Villavicencio. Métodos: Se realizó un estudio de tipo observacional, analítico en dos barrios de la ciudad Villavicencio: Quintas de San Fernando y Cedritos. El formato de levantamiento de índices aédicos de la secretaría de salud fue diseñado en dos medios electrónicos. La eficacia fue determinada mediante datos efectivos recogidos y tiempo de entrega. Se calcularon índices aédicos, Breteau, vivienda y pupas. Se realizó encuesta para determinar actitudes frente a arbovirosis. Se realizó estadística descriptiva, pruebas de chi cuadrado y t-Student (p< 0,05). Resultados: Se evaluaron 67 predios en dos barrios. El índice de datos efectivos fue mejor en donde el acceso a internet era permanente (100 por ciento vs. 23,9 por ciento); el tiempo de entrega también se afectó por esta conexión. Se encontraron diferencias significativas en el número de viviendas positivas para Aedes aegypti entre los dos barrios (p= 0,0052); y para el número de tanques bajos positivos (p= 0,0123). De los encuestados, el 16,4 por ciento (IC95 por ciento 8,9 por ciento-27,5 por ciento) sabía que la transmisión fue por picadura de Ae. aegypti. Para el 79,1 por ciento, cada familia fue responsable de eliminar criaderos. Conclusiones: El uso de herramientas electrónicas permite acelerar el flujo de la información y crear un sistema eficaz, de fácil acceso y seguridad que podría implementarse permanentemente en la vigilancia entomológica y de salud pública(AU)

Objective: Determine the effectiveness of two electronic tools for the evaluation of aedic indices in the city of Villavicencio. Methods: An observational analytic study was conducted in two districts in the city of Villavicencio: Quintas de San Fernando and Cedritos. The form designed by the Ministry of Health to evaluate aedic indices was digitalized into two electronic media. Efficacy was determined on the basis of effective data collected and delivery time. An estimation was made of aedic indices, Breteau, household and pupae. A survey was conducted to determine attitudes to arbovirus infections. Use was made of descriptive statistics, chi-squared tests and Student's t-test (p< 0.05). Results: Sixty-seven households were evaluated in two districts. The effective data index was better in areas where access to the Internet was permanent (100 percent vs. 23.9 percent). Delivery time was also affected by Internet connection. Significant differences were found between the two districts in the number of positive households for Aedes aegypti (p= 0.0052), as well as in the number of positive ground water tanks (p= 0.0123). Of the respondents, 16.4 percent (95 percent CI, 8.9 percent-27.5 percent) were aware that transmission had been by the bite of Ae. aegypti mosquitoes. For 79.1 percent each family was responsible for eliminating the breeding sites. Conclusions: Use of electronic tools speeds up the flow of information and creates an effective, easily-accessible and safe system which could be permanently implemented for entomological and public health surveillance(AU)

Improved dengue fever prevention through innovative intervention methods in the city of Salto, Uruguay.

BACKGROUND: Uruguay is located at the southern border of Aedes aegypti distribution on the South American sub-continent. The reported dengue cases in the country are all imported from surrounding countries. One of the cities at higher risk of local dengue transmission is Salto, a border city with heavy traffic from dengue endemic areas. METHODS: We completed an intervention study using a cluster randomized trial design in 20 randomly selected 'clusters' in Salto. The clusters were located in neighborhoods of differing geography and economic, cultural and social aspects. RESULTS: Entomological surveys were carried out to measure the impact of the intervention on vector densities. Through participatory processes of all stakeholders, an appropriate ecosystem management intervention was defined. Residents collected the abundant small water holding containers and the Ministry of Public Health and the Municipality of Salto were responsible for collecting and eliminating them. Additional vector breeding places were large water tanks; they were either altered so that they could not hold water any more or covered so that oviposition by mosquitoes could not take place. CONCLUSIONS: The response from the community and national programme managers was encouraging. The intervention evidenced opportunities for cost savings and reducing dengue vector densities (although not to statistically significant levels). The observed low vector density limits the potential reduction due to the intervention. A larger sample size is needed to obtain a statistically significant difference.

Study of the relationship between Aedes (Stegomyia) aegypti egg and adult densities, dengue fever and climate in Mirassol, state of São Paulo, Brazil

The purpose of this study was to examine the relationship between Aedes aegypti egg and adult density indices, dengue fever and climate in Mirassol, state of São Paulo, Brazil, between November 2004-November 2005. Weekly collections of adults and eggs were made using, respectively, manual aspirators and oviposition traps that produced four entomological indices (positivity and average of females and eggs). Weekly incidence coefficients were calculated based on dengue cases. Each week, the data obtained from entomological indices were related to each other, dengue, and climate variables. The first index to show an association with dengue transmission was the female average, followed by female positivity and egg average. Egg positivity did not show a relationship with risk for dengue, but was sensitive to identifying the presence of the vector, principally in dry seasons. The relationship between climatic factors, the vector and the disease found in this study can be widely employed in planning and undertaking dengue surveillance and control activities, but it is a tool that has not been considered by the authorities responsible for controlling the disease. In fact, this relationship permits the use of information about climate for early detection of epidemics and for establishing more effective prevention strategies than currently exist.