Investigação do perfil sorológico e detecção do DNA de Leishmania spp. em cães de áreas endêmicas para Leishmaniose tegumentar americana no estado do Pará, Brasil

Abstract

Despite the records of dogs infected by Leishmania spp., the role of animals in the transmission cycle of the agents of American Tegumentary Leishmaniasis (ATL) transmission has not been elucidated. This study aimed to investigate the frequency of the canine infection in rural localities from Ulianópolis, Dom Eliseu and Rondon do Pará county, where so far no reported cases of human or canine visceral leishmaniasis (VL). From May to December 2011, were investigated 224 dogs in rural areas of three counties. From dogs with lesions were collected material for the direct detection of parasites. For indirect immunofluorescence assay (IFA) were used as antigen promastogotes L. (V.) braziliensis, L. (V.) shawi, L. (L.) amazonensis e L. (L.) infantum chagasi, reagents be considered sera with titers equal to or greater than 40. The DNA extraction from blood sample was performed using phenol:chloroform:isoamyl alcohol, which was subsequently used for molecular detection by the Polymerase Chain Reaction technique (PCR). Primers S1629 and S1630 were used to amplify the mini-exon genes. Of the 224 dogs studied, 18 (8,04%) had lesions suggestive of ATL, of which only five was positive for the direct detection of parasites. In the serologic survey, 118 (52,68%) canine serum were reagent at least on of the antigens tested, with the highest percentage of global agreement (91,96%) was found in the association between the results of the antigens of L. (V.) braziliensis and L. (V.) shawi. In molecular research, among the 74 (33,04%) dogs with positive PCR detected DNA from Leishmania subgenus Viannia in 68 (91,89%), and four (5,40%) animals DNA L. (L.) amazonensis, whereas two (2,70%) dogs had mixed infection. No DNA was found compatible with L. (L.) infantum chagasi. The high frequency of dogs with reactive serum and the detection of DNA from Leishmania indicating the presence of infected dogs and greater circulation of the subgenus Leishmania Viannia than L. (L.) amazonensis in this region, however even with a large number of animals without clinical signs lerger studies are still needed to clarify the role of dogs in the transmission cycle of agents of the ATL.