BackgroundThe scarcity of information on the immature stages of sand flies and their preferred breeding sites has resulted in the focus of vectorial control on the adult stage using residual insecticide house-spraying. This strategy, along with the treatment of human cases and the euthanasia of infected dogs, has proven inefficient and visceral leishmaniasis continues to expand in Brazil. Identifying the breeding sites of sand flies is essential to the understanding of the vector's population dynamic and could be used to develop novel control strategies.Methodology/Principal findingIn the present study, an intensive search for the breeding sites of Lutzomyia longipalpis was conducted in urban and peri-urban areas of two municipalities, Promissão and Dracena, which are endemic for visceral leishmaniasis in São Paulo State, Brazil. During an exploratory period, a total of 962 soil emergence traps were used to investigate possible peridomiciliary breeding site microhabitats such as: leaf litter under tree, chicken sheds, other animal sheds and uncovered debris. A total of 160 sand flies were collected and 148 (92.5%) were L. longipalpis. In Promissão the proportion of chicken sheds positive was significantly higher than in leaf litter under trees. Chicken shed microhabitats presented the highest density of L. longipalpis in both municipalities: 17.29 and 5.71 individuals per square meter sampled in Promissão and Dracena respectively. A contagious spatial distribution pattern of L. longipalpis was identified in the emergence traps located in the chicken sheds.ConclusionThe results indicate that chicken sheds are the preferential breeding site for L. longipalpis in the present study areas. Thus, control measures targeting the immature stages in chicken sheds could have a great effect on reducing the number of adult flies and consequently the transmission rate of Leishmania (Leishmania) infantum chagasi.

Sandflies were captured in a secondary forest zone in the county of Teodoro Sampaio, São Paulo, during 12 months as from May 1994. Two houses located respectively at 240 m and 850 m from the semi-deciduous forest were selected. Night Center of Disease Control trap captures were performed fortnightly from twilight to dawn intradomiciliarily, in the edge and the interior of the forest and in the peridomicile of each one of the houses. Captures were realized as well in the peridomicile using Shannon traps during 6 hour for 24 captures and 4 quarter captures from twilight to dawn. The dominant species was Lutzomyia intermedia (93.5%). A larger number of insects were captured in the traps located in the edge of the forest. In the peridomicile of both houses an equivalent number of insects were captured, although a clear predominance of males was observed in the more distant located house. In the interior of the house located near the forest a larger number of specimens predominantly female were captured. L. intermedia and L. whitmani peaks occurred in the first hour and were characteristically more abundant in May, September and December when the mean temperature varied from 21 to 25.7 degrees C and the pluviometric index as from 66.7 to 195.1 mm.

Following reports of two autochthonous cases of sylvatic yellow fever in the State of São Paulo, Brazil, in 2000, entomological surveys were conducted with the objective of verifying the occurrence of vector species in forest environments close to or associated with riparian areas located in the western and northwestern regions of the State. Culicidae were captured in 39 sites distributed in four regions. Haemagogus leucocelaenus and Aedes albopictus were the most abundant species and were captured in all the regions studied. H. leucocelaenus was the most abundant species in the municipalities of Santa Albertina and Ouroeste, where the two cases of sylvatic yellow fever had been reported. Mosquitoes from the janthinomys/capricornii group were only found at eight sites in the São José do Rio Preto region, while Sabethes chloropterus was found at one site in Ribeirão Preto. H. leucocelaenus showed its capacity to adapt to a secondary and degraded environment. Our results indicate a wide receptive area for yellow fever transmission in the State of São Paulo, with particular emphasis on the possibility of H. leucocelaenus being involved in the maintenance of this sylvatic focus of the disease.

No abstract

No abstract

The specimen distribution pattern of a species can be used to characterise a population of interest and also provides area-specific guidance for pest management and control.

RESUMOO objetivo deste estudo foi analisar a vigilância da doença de Chagas no Estado de São Paulo, através da notificação, na década de 1990. As informações foram originadas quando da notificação de triatomíneos pelos moradores e seguiram o normatizado pelo Programa de Controle. Foram recebidas 20.563 notificações de triatomíneos com queda ao longo dos anos, sendo esta mais acentuada na região que compreende a área de maior freqüência de encontro de Panstrongylus megistus. Cada notificação correspondeu em média a 1,3 exemplares de triatomíneos capturados (mediana=1), predominantemente no intradomicílio, enquanto nos atendimentos a média de insetos coletados foi de 3,6 (mediana=2), presentes na maioria no peridomicílio. A distribuição das notificações permitiu demarcar três áreas distintas do Estado: área 1-compreendida pelas regiões de São José do Rio Preto, Araçatuba e parte de Presidente Prudente; área 2-São Vicente e Sorocaba; área 3-municípios situados a nordeste da região de Campinas. A análise mostrou que a vigilância entomológica através da notificação de triatomíneos, a despeito da queda das mesmas, não tem detectado colônias intradomiciliares associadas a infecção por Trypanosoma cruzi que possam dar origem à transmissão vetorial da doença de Chagas humana. Palavras-chaves: Doença de Chagas. Programa de Controle. Notificações de triatomíneos. Vigilância entomológica. ABSTRACTThe objective of this study was to analyze the surveillance of Chagas' disease in São Paulo State through notifications registered from 1990 to 1999. The information originated when notification of triatomines was announced by inhabitants and the established control program was followed. 20,563 triatomine notifications were received, showing a decrease over the years, with more accentuated decreases in the area of greatest frequency of Panstrongylus megistus. Each notification corresponded to an average of 1.3 examples of captured triatomines (median = 1), predominantly in the intradomicile area, while during attendance, the mean number of collected insects was 3.6 (median = 2), mostly present in the peridomicile area. The notification distribution permitted the demarcation of three different areas in the state: area 1, comprising the areas of São José do Rio Preto, Araçatuba and part of Presidente Prudente; area 2, São Vicente and Sorocaba; area 3, municipalities located to the northeast of the Campinas region. Analysis showed that entomological surveillance through triatomine notification, despite the fall in the same, has not detected intradomiciliary colonies associated with Trypanosoma cruzi which could give rise to vectorial transmission of Chagas' disease.

This study aims to analyze the effect of domiciliary infestation by triatomine bugs on the degree to which inhabitants are aware of potential vector transmission of Chagas disease. Such recently constructed dwellings comprise housing groups classified as settlements and re-settlements, selected respectively in the municipalities of Euclides da Cunha Paulista and Paulicéia, São Paulo State, Brazil. Both municipalities are under the jurisdiction of the Presidente Prudente Health Administrative Region. Of the 319 residents, some 100 (76.0% of whom were re-settlement residents) knew about triatomine bugs. Housing units infested with triatomines were inhabited by 93 people. In 79.2% of the infested houses, 26.8% of the residents knew about Chagas disease and its vectors, but in 50.0% of the households, some people did not know what to do in case of triatomine infestation. Population samples from settlements and re-settlements, regardless of sex, age, and the State of origin, showed no difference in attitudes towards the prevention of Chagas disease or knowledge of the disease vector.