Leishmaniose visceral canina na Zona Rural do Município de Patos - PB: aspectos epidemiológicos e padronização de um ensaio sorológico.

Abstract

In Brazil, visceral leishmaniasis is caused by Leishmania (Leishmania) infantum chagasi. It is a chronic zoonosis and considered a worldwide public health problem. Chapter I describes the prevalence and risk factors of canine visceral leishmaniasis (CVL) in Patos, Paraíba, and evaluate the performance of serological tests commonly used in CVL (ELISA, IFA and Test DPP immunoassay). 362 blood samples were collected and serologic prevalence was determined from samples that were positive in at least two serological tests. The owners answered an epidemiological questionnaire to identify potential risk factors. Estimated seroprevalence was 11.33% (41/362). ELISA was taken as the gold standard because it is established as the confirmatory test to CVL by the Ministry of Health. Dual Path Platform (DPP) had a sensitivity of 58.33% and specificity of 95.54%. IFA had a sensitivity of 83.33% and specificity of 99.36%. The comparison of serological tests showed that DPP is not the best technique to screen for positive animals due to its low sensitivity. By multivariate analysis, animal gender was identified as risk factor and male dogs were two times more likely to develop the disease, what can be justified because of their use in hunting and as guard dogs, increasing the contact with other animals and with phlebotomine sand flies. The prevalence of canine visceral leishmaniasis has increased considerably in the county of Patos, Paraíba, which indicates the urgent need to take control measures. Chapter II describes the development and standardization of a latex agglutination test based on a recombinant protein (HSP70) of Leishmania (L.) infantum chagasi for the diagnosis of canine visceral leishmaniasis. Forty serum samples, 20 from positives and 20 from negative animals, were tested at three different dilutions. The best result was on 1:4, with a sensitivity of 75% and specificity of 90%. The Rapid Latex Agglutination Test is a good screening method, being fast and of easy handling; the use of purified antigen may enhance the assay sensitivity.