ABSTRACT
West Nile virus is characterized as a neurotropic pathogen, which can cause West Nile fever and is transmitted by mosquitoes of the genus Culex. In 2018, the Instituto Evandro Chagas performed the first isolation of a WNV strain in Brazil from a horse brain sample. The present study aimed to evaluate the susceptibility of orally infected Cx. quinquefasciatus from the Amazon region of Brazil to become infected and transmit the WNV strain isolated in 2018. Oral infection was performed with blood meal artificially infected with WNV, followed by analysis of infection, dissemination, and transmission rates, as well as viral titers of body, head, and saliva samples. At the 21st dpi, the infection rate was 100%, the dissemination rate was 80%, and the transmission rate was 77%. These results indicate that Cx. quinquefasciatus is susceptible to oral infection by the Brazilian strain of WNV and may act as a possible vector of the virus since it was detected in saliva from the 21st dpi.
ABSTRACT
ABSTRACT: This study was designed to detect L. infantum infection in dogs and to evaluate the factors associated with canine visceral leishmaniasis in the maroon communities of Menino Jesus de Petimandeua and Itaboca in the municipality of Inhangapi, Pará, Brazil. Whole blood and intact skin samples were collected from 143 dogs, and a questionnaire was applied. L. infantum DNA was detected by polymerase chain reaction (PCR) using primers RV1 and RV2. Collection sites were georeferenced to obtain a spatial distribution of the residences visited and infected dogs. L. infantum DNA was detected in 8.4% (12/143) of the skin samples and in 1.4% (2/143) of the blood samples. On the risk map, three clusters were observed in Itaboca and one was observed in Menino Jesus de Petimandeua. We observed that most of the inhabitants in these maroon communities live close to forested areas and do not use protection against insect vectors. The presence of canine reservoirs of L. infantum associated to environment characteristics (preserved forests and deforested areas) and habits of dog owners (living near forested areas and not using any protection against insects) may favor the transmission of L. infantum in the studied areas.
RESUMO: O presente estudo objetivou detectar a infecção por Leishmania infantum em cães e avaliar os fatores associados com a leishmaniose visceral canina nas comunidades quilombolas Menino Jesus de Petimandeua e Itaboca, município de Inhangapi, Pará, Brasil. Foram coletadas amostras de sangue e de pele íntegra de 143 cães, sendo aplicado um questionário. A detecção do DNA de L. infantum foi realizada através da PCR com os iniciadores RV1 e RV2. Os locais de coleta foram georreferenciados para realizar a distribuição e análise espacial das residências visitadas e dos cães infectados. DNA de L. infantum foi detectado em 8,4% (12/143) das amostras de pele dos cães e em 1,4% (2/143) das amostras de sangue. No mapa de risco, foram observados três aglomerados em Itaboca e um em Menino Jesus de Petimandeua. Pôde-se constatar que a maioria dos moradores das comunidades quilombolas reside em áreas próximas de mata e não utilizam proteção contra insetos vetores. A presença de reservatórios caninos de L. infantum associada com características ambientais (floresta preservada e áreas de desmatamento) e os hábitos dos proprietários dos cães (que vivem perto de áreas de floresta e não usam qualquer tipo de proteção contra insetos) podem favorecer a transmissão de L. infantum nas áreas estudadas.
