A preliminary study on the distribution of breeding sites of BIOMPHALARIA GLABRATA in the municipality of peri mirim, a low endemicity area for schistosomiasis in northeast Brazil

Information on areas colonized by snails that transmit Schistosoma mansoni is essential for planning schistosomiasis control measures. Therefore, the purpose of this study was to map the natural breeding sites of Biomphalaria spp. in the municipality of Peri Mirim, Maranhão, Brazil. The snails were manually collected and the breeding sites were geo-referenced (seven in the urban area and five in flooded fields), from November 2017 to March 2018. In the laboratory, the snails were examined for the presence of larval stages of S. mansoni identified by morphology and internal anatomy analysis. While no snails were found in the urban area, sixteen B. glabrata were collected in the flooded fields. No S. mansoni or other trematode infections were detected. Wild rodents, most likely Holochilus sciureus that could act as S. mansoni reservoirs, were also found in the flooded fields. These data indicate possible risk areas for further outbreaks of schistosomiasis transmission in the municipality of Peri Mirim.

Use of ovitraps for the seasonal and spatial monitoring of Aedes spp. in an area endemic for arboviruses in Northeast Brazil.

INTRODUCTION: Due to recent outbreaks of Dengue and Chikungunya and an absence of effective monitoring of the mosquito Aedes spp. in the municipality of São Raimundo das Mangabeiras, State of Maranhão, we aimed to demonstrate the potential of ovitraps used together with mathematical models and geotechnology to improve control of this mosquito. METHODOLOGY: From January to December of 2017, ovitraps were set up in five different neighborhoods (Centro, Vila Cardoso, Nazaré, São José e São Francisco). Positivity indices were calculated for each ovitraps, besides the egg density and average number of eggs. Some of the eggs were used for species identification. Mathematical models of correlation and logistic regression were used to evaluate the influence of abiotic factors on egg distribution during each month. Spatial analysis was carried out using georeferencing. RESULTS: A total of 4,453 eggs were counted, with A. aegypti and A. albopictus present in each month and neighborhood. The mathematical models show that rainfall can result in a significant increase in the number of eggs. Entomological calculation indicates that there is a high risk of dissemination of arboviruses in the area. Spatially, it was possible to indicate sites with the largest number of collected eggs, which may facilitate future interventions. CONCLUSIONS: As such, ovitraps have proven to be an effective and low cost method for the monitoring of Aedes spp., and that its use may help in arboviruses prevention campaigns.