Novel findings on the role of ficolins and colectins in the innate response against Leishmania braziliensis.

Leishmania (Viannia) braziliensis is the main agent of mucocutaneous Leishmaniasis, a neglected tropical disease that affects thousands of people in Brazil. It has been shown that complement plays a critical role at early stages of Leishmania infection and that is involved in the invasion of macrophages by the promastigotes. Ficolins and collectins are soluble pattern recognition and triggering molecules of the lectin complement pathway. We investigated here whether lectin pathway activators ficolin-1, ficolin-2, ficolin-3 and CL-11 bind to live L. braziliensis promastigotes in vitro. Promastigote forms in the stationary growth phase were incubated with normal human serum (NHS) or recombinant ficolins 1, 2 and 3, MBL and CL-11, and protein binding was evaluated by confocal microscopy and flow cytometry. Ficolins 1, 2 and 3, MBL and CL-11 were able to bind to the surface of live promastigotes after incubation with either NHS or recombinant proteins. A partial inhibition by N-acetyl-d-glucosamine characterizing the participation of acetylated groups in the deposition of ficolins and CL-11 to glycoconjugates on the surface of L. braziliensis was observed. These evidences highlight a role for the lectin pathway in the innate response to L. braziliensis.

Use of the high-content imaging system equipment to evaluate in vitro infection by Leishmania braziliensis in response to sand fly Nyssomyia neivai saliva.

Earlier research has shown that in vivo immunization with sand fly saliva protects the host against infection by parasites of genus Leishmania, and inoculation of saliva along with Leishmania promastigotes favors infection in the host. In this study, High-Content Imaging System was used to demonstrate in vitro that sand fly saliva also promotes infection by these parasites. THP-1 cells were cultured in 96-well microplates and challenged with three strains of Leishmania braziliensis plus four dilutions of Nyssomyia neivai salivary gland extract. High-Content Imaging System equipment (Operetta CLS, Perkin Elmer) was configured to automatically count both cells and parasites inside the microplates and subsequently calculate the Infection Index (II). Results demonstrate that the extract concentration of 1 gland showed greater infection than other dilutions. These findings suggest that sand fly N. neivai saliva has potential for increasing the parasite infection, reinforcing the importance of studying its components. A new method to evaluate Leishmania infection in vitro assays was also presented, broadening this area of study.

Eclectic feeding behavior of Lutzomyia (Nyssomyia) intermedia (Diptera, Psychodidae, Phlebotominae) in the transmission area of American cutaneous leishmaniasis, state of Paraná, Brazil.

INTRODUCTION: The blood meal source of sandflies provides valuable information about the vector/host interaction and allows for an understanding of American cutaneous leishmaniasis (ACL) transmission mechanisms. The aim of this study was to identify the blood meal sources of Lutzomyia (Nyssomyia) intermedia in an endemic area of leishmaniasis in Brazil's State of Paraná using a precipitin test. METHODS: Sandflies were collected in the rural locality of Epitácio Pessoa within the City of Adrianópolis, State of Paraná, in southern Brazil. A total of 864 female sandflies were captured, and 862 (99.8%) were identified as L. intermedia species. However, two unidentified specimens were considered to be part of the genus Lutzomyia. RESULTS: Among the females examined, 396 specimens presented reactions to a certain type of tested antiserum, and most (67.9%) reacted to the simple type. These sandflies fed mainly on the blood of birds, opossums, and rodents, but specimens that fed on the blood of humans, dogs, horses, cattle, and cats were also found. Among the cross-reactions found (32.1%), bird/rodent, bird/opossum, bird/dog, bird/human, and horse/dog cross-reactions were the most common. CONCLUSIONS: These results demonstrate a tendency in the eclectic feeding behavior of L. intermedia and support its potential role as a vector for ACL in the study area.

Eclectic feeding behavior of Lutzomyia (Nyssomyia) intermedia (Diptera, Psychodidae, Phlebotominae) in the transmission area of American cutaneous leishmaniasis, state of Paraná, Brazil

Introduction The blood meal source of sandflies provides valuable information about the vector/host interaction and allows for an understanding of American cutaneous leishmaniasis (ACL) transmission mechanisms. The aim of this study was to identify the blood meal sources of Lutzomyia (Nyssomyia) intermedia in an endemic area of leishmaniasis in Brazil's State of Paraná using a precipitin test. Methods Sandflies were collected in the rural locality of Epitácio Pessoa within the City of Adrianópolis, State of Paraná, in southern Brazil. A total of 864 female sandflies were captured, and 862 (99.8%) were identified as L. intermedia species. However, two unidentified specimens were considered to be part of the genus Lutzomyia. Results Among the females examined, 396 specimens presented reactions to a certain type of tested antiserum, and most (67.9%) reacted to the simple type. These sandflies fed mainly on the blood of birds, opossums, and rodents, but specimens that fed on the blood of humans, dogs, horses, cattle, and cats were also found. Among the cross-reactions found (32.1%), bird/rodent, bird/opossum, bird/dog, bird/human, and horse/dog cross-reactions were the most common. Conclusions These results demonstrate a tendency in the eclectic feeding behavior of L. intermedia and support its potential role as a vector for ACL in the study area. .

Variabilidade genética de Aedes (Stegomyia) aegypti no Brasil / Genetic variability of Aedes (Stegomyia) aegypti in Brazil

Aedes aegypti está presente em todos os Estados brasileiros e cerca de 75por cento dos casos de dengue registrados na América são reportados no Brasil. O Rio de Janeiro, importante centro comercial e turístico, servido de importantes rodovias, portos e aeroportos que favorecem sua conexão nacional e internacional, é considerado um dos mais importantes pontos de disseminação do vírus dengue no país. Com o objetivo de avaliar a estrutura genética de Ae. aegypti em caráter espaço-temporal, foram utilizados 3 marcadores- isoenzimas, microssatélites e DNA mitocondrial- em amostras coletadas trimestralmente, de dezembro/2002 a dezembro/2003, em 24 áreas urbanas com variáveis incidências de casos de dengue e densidade populacional humana, sendo 14 bairros da cidade do Rio de Janeiro, 9 cidades de 4 estados do Sudeste (RJ, SP, MG, ES) e Porto Alegre, na região Sul, onde nunca houve transmissão dessa arboirose. Os resultados baseados nos marcadores de isoenzimas e microssatélites evidenciaram baixo fluxo gênico entre as populações de Ae. aegypti, em escalas microrregional (dentro da cidade do Rio de Janeiro) e macrorregional (entre as áreas endêmicas e indenes). Foi detectada elevada diferenciação genética aos níveis intra e interpopulacionais, evidenciada por elevados valores de Fst, o que tendeu a persistir ao longo de todo o ano. Contudo, o grau de estruturação genética das populações revelou interferências temporais, as quais foram heterogêneas em função da área estudada. Na maioria das amostras da cidade do Rio de Janeiro, os valores de Fst, ainda que elevados...estação seca. A correlação entre diferenciação genética das populações e distância em quilômetros não foi significante na quase totalidade das análises, sugerindo que a dispersão passiva desse mosquito ao longo das rotas pesquisadas não parece ser suficientemente freqüente para promover homogeneização genética. A análise do DNA mitocondrial revelou 2 grupos distintos: um que inclui amostras do Sudeste e...