Influence of Deforestation on the Community Structure of Sand Flies (Diptera: Psychodidae) in Eastern Amazonia.

Variation in the structure of phlebotomine (sand fly) communities in forest fragments with different degrees of preservation and human occupation (peridomicile) in eastern Amazonia was studied. We identified 43 species of sand flies in our study, of which 38 occurred in both preserved forest areas and in the peridomiciles of short-term settlements, while another 28 species occurred in altered forest fragments and long-term settlements. The composition of the community at each site changed with the type of environment (forest or peridomicile), with the species Lutzomyia evandroi, L. whitmani, L. choti, L. serrana, L. triacantha, L. migonei, L. hirsuta, L. shannoni, and L. brachyphylla accounting for more than 54% of the differences among environments. The quality of the environment exerted a significant influence on the structure of phlebotomine communities, and affected their species composition, richness, and abundance.

[Feeding preference of sand flies in the Amazon, Maranhão State, Brazil]. / Preferência alimentar sanguínea de flebotomíneos da Amazônia do Maranhão, Brasil.

The objective of this study was to determine the blood feeding sources for sand flies based on the precipitin test in Buriticupu, Amazon Region, Maranhão State, Brazil, from July 2002 to June 2004. Single (87.6%) and double (8%) reactions and non-reactive samples (4.4%) were found. The presence of sand flies fed on human blood (6.7%) and blood of animals that are possible peridomiciliary Leishmania reservoirs helps explain the reporting of autochthonous tegumentary leishmaniasis cases in Buriticupu.

Preferência alimentar sanguínea de flebotomíneos da Amazônia do Maranhão, Brasil / Feeding preference of sand flies in the Amazon, Maranhão State, Brazil

O objetivo deste estudo foi determinar as fontes alimentares sanguíneas de flebotomíneos por meio da reação da precipitina, em Buriticupu, na Amazônia maranhense, Brasil, de julho de 2002 a junho de 2004. Foram detectadas reações simples (87,6 por cento), duplas (8 por cento) e não reagentes (4,4 por cento). A presença de flebotomíneos alimentados com sangue humano (6,7 por cento) e de possíveis reservatórios de Leishmania no peridomicílio ajuda a explicar a ocorrência de casos autóctones de leishmaniose tegumentar no Município de Buriticupu.

The objective of this study was to determine the blood feeding sources for sand flies based on the precipitin test in Buriticupu, Amazon Region, Maranhão State, Brazil, from July 2002 to June 2004. Single (87.6 percent) and double (8 percent) reactions and non-reactive samples (4.4 percent) were found. The presence of sand flies fed on human blood (6.7 percent) and blood of animals that are possible peridomiciliary Leishmania reservoirs helps explain the reporting of autochthonous tegumentary leishmaniasis cases in Buriticupu.

Diagnóstico molecular da taxa de infecção natural de flebotomíneos (Psychodidae, Lutzomyia) por Leishmania sp na Amazônia maranhense / Molecular diagnosis of the natural infection rate due to Leishmania sp in sandflies (Psychodidae, Lutzomyia) in the Amazon region of Maranhão, Brazil

A taxa de infecção natural de três diferentes espécies de flebotomíneos por Leishmania foi estudada usando a técnica de reação em cadeia da polimerase. Primers específicos para Leishmania foram designados para examinar se os pools de flebotomíneos estavam infectadas. Um total de 1.100 fêmeas separadas em pools de 10 indivíduos foram examinados, consistindo de 50 Lutzomyia whitmani, 43 Lutzomyia triacantha e 17 Lutzomyia choti. De todos os pools analisados, 4 de Lutzomyia whitmani estavam positivos, mas nenhum pool das duas espécies restantes estava infectado. Deste modo, uma taxa de infecção de 0,4 por cento foi verificada neste estudo. Esta taxa de infecção associada a estudos anteriores sugere que Lutzomyia whitmani transmite Leishmania aos mamíferos em Buriticupu, Maranhão.

The natural infection rate due to Leishmania was studied in three different sandfly species using the polymerase chain reaction technique. Leishmania specific primers were designed to examine whether sandfly pools were infected. In total 1,100 female sandflies separated into pools of 10 individuals, consisting of 50 pools of Lutzomyia whitmani, 43 of Lutzomyia triacantha and 17 of Lutzomyia choti, were analyzed. Among all the pools examined, four pools of Lutzomyia whitmani were positive, but none of the pools of the other two species were infected. Thus, a total infection rate of 0.4 percent was established in this study. A similar infection rate was found in previous studies, suggesting that Lutzomyia whitmani transmits Leishmania to mammals in Buriticupu, Maranhão.

[Molecular diagnosis of the natural infection rate due to Leishmania sp in sandflies (Psychodidae, Lutzomyia) in the Amazon region of Maranhão, Brazil]. / Diagnóstico molecular da taxa de infecção natural de flebotomíneos (Psychodidae, Lutzomyia) por Leishmania sp na Amazônia maranhense.

The natural infection rate due to Leishmania was studied in three different sandfly species using the polymerase chain reaction technique. Leishmania specific primers were designed to examine whether sandfly pools were infected. In total 1,100 female sandflies separated into pools of 10 individuals, consisting of 50 pools of Lutzomyia whitmani, 43 of Lutzomyia triacantha and 17 of Lutzomyia choti, were analyzed. Among all the pools examined, four pools of Lutzomyia whitmani were positive, but none of the pools of the other two species were infected. Thus, a total infection rate of 0.4% was established in this study. A similar infection rate was found in previous studies, suggesting that Lutzomyia whitmani transmits Leishmania to mammals in Buriticupu, Maranhão.

Espécies de Anopheles no município de Pinheiro (Maranhäo), área endêmica de malária / Species of Anopheles in Pinheiro municipality (Maranhäo), endemic area of malaria

A riqueza, abundância relativa, flutuaçäo sazonal, preferência por ambiente (peri e intradomicílio) e horários de hematofagismo de espécies de Anopheles foram estudados no município de Pinheiro, Maranhäo. As fêmeas foram capturadas mensalmente sobre iscas humanas de maio 1998 a abri1/1999, das 18 às 6 horas. Foram coletados 1.321 espécimens pertencentes a 10 espécies de Anopheles, todas do subgênero Nyssorhynchus: A. argyritarsis com 62 por cento, A. darlingi (21,7 por cento), A. albitarsis (4,5 por cento), A. galvaoi (4 por cento), A. triannulatus (3,1 por cento) e A. evansae (2,8 por cento). As espécies A. nuneztovari, A. braziliensis, A. rondoni e A. strodei representaram juntas 1,9 por cento. Os anofelinos ocorreram o ano todo, näo havendo diferença significativa no número de exemplares capturados entre as estaçöes chuvosa (51,7 por cento) e seca (48,3 por cento). A freqüência dos anofelinos no peridomicílio foi significativamente maior (p < 0,01) (82 por cento) do que no intradomicílio (18 por cento), preferindo sugar no crepúsculo vespertino e nas primeiras horas da noite