Leishmaniose visceral canina em cães atendidos em hospital veterinário particular do Distrito Federal, Brasil

Visceral leishmaniasis is a neglected disease with about 0.2 to 0.4 million of new cases per year worldwide, and Brazil is one of the six countries with the highest number of cases. The domestic dog is considered the main urban reservoir of the agent Leishmania infantum which is mainly transmitted by the sand fly vector Lutzomya longipalpis. Canine visceral leishmaniasis has chronic character and infected dogs in endemic areas can not show overt clinical signs, hindering detection and control of the disease. The canine cases may be associated with human cases, because of the proximity between man and the domestic dog. The Ministry of Health recommends the use of serological tests for the detection of positive dogs for the disease and their euthanasia, but these tests have limitations in terms of sensitivity and specificity. Molecular tests such as PCR-RFLP have shown great advantages over conventional assays in diagnosis and species identification of the parasite. In this way, the present report evaluate Leishmania DNA detection of ITS1 ribosomal DNA or 3’-UTR of the HSP70 gene in bone marrow samples from dogs attended in a veterinary hospital in the Federal District (DF-Brazil). Parasite detection was followed by species identification through PCR-RFLP. Furthermore we compared the molecular testing with some parasitological, serological, clinical and biochemical characteristics of these animals. The ITS1 PCR reactions and 3'-UTR of HSP70 gene showed 78.69% and 52.46% of positivity respectively. Parasitological tests detected only 40.98% of the positive samples, and L. infantum was the only species identified by RFLP. Symptoms include weight loss, gastrointestinal disorders, weakness, epistaxis and uveitis. Dog-eared, short hair and large were in greater proportion of the positive dogs. It was also observed anemia, thrombocytopenia and alterations of the normal values of the number of leukocytes in these animals. In biochemical profile, only ALT (alanine transaminase) was significantly higher in dogs with positive molecular detection. It was concluded that the molecular tools are potent for the Leishmania detection and identification of positive dogs in endemic areas, and allow diagnosis in asymptomatic dogs. Thus the molecular test becomes essential for the completion of diagnosis in veterinary clinic, allowing the correct actions to control this disease.