The first aim of this study is to lead an epidemiological investigation by the polymerase chain reaction (PCR) which allows the detection of Leishmania (Leishmania) chagasi in individual Rhipicephalus sanguineus ticks from positive and negative dogs to canine visceral leishmaniasis through serological, parasitological and molecular assays. The second objective will determine the role of the tick as intermediary host of the protozoan mentioned above. A total of 99 dogs will be used, with 66 seropositive for this agent from two endemic municipalities (33 of Araçatuba, São Paulo (SP) and 33 from Campo Grande, Mato Grosso do Sul) and 33 seronegative (from Jaboticabal, SP , non-endemic area). These animals, both male and female, of different breeding and with age more than one year. Blood samples will be processed by the techniques of Immunofluorescence Assay (IFA) and enzyme linked immunosorbent assay (ELISA). Aspiration biopsies will be performed for the direct parasitological examination "imprint" of lymph nodes and after that this material will be examined by Polymerase Chain Reaction (PCR). In the whole of 10 ticks of R. sanguineus species will be collected from each dog. Genomic DNA will be purified from the guts, ovaries, salivary glands and eggs of the individual ticks and the PCR assay will be used to verify the presence or absence of Leishmania (Leishmania) chagasi. It will be also performed immunohistochemistry reaction of those same organs. Due to absence of the epidemiological studies concerning the occurrence of this protozoan in this species of ticks and because of their inconclusive role as intermediary host, justifies the performance of this research.
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