Detecção de Leishmania (Ross, 1903) em Rattus norvegicus (Berkenhout,1769) em Belo Horizonte, Minas Gerais, 2007 e 2008

Abstract

The cutaneous leishmaniasis (CL) is widespread and involves many species of Leishmania and a variety of vectors and hosts in a complex epidemiology. The aim of the study was the screening for isolation and culture in biphasic medium, imprints of tissues in slides, Immunoenzimatic Assay (ELISA), Indirect Immunofluorescence (IFI) and LnPCR followed by sequencing of Leishmania sp. in Rattus norvegicus captured in the area of transmission of leishmaniasis in Belo Horizonte, Minas Gerais. Diagnostic techniques (direct isolation and culture) revealed no visible amastigotes and promastigotes in samples analysed. Serological tests identified 43.75% (35/80) positive animals by ELISA. In the IFI was assessed in each sample dilutions 1:40, 1:80 and 1:160, where 70% (56/80) of animals were positive (10% 1:160; 33.75% and 26 to 1:80 25% at 1:40) and 30% (24/80) were negative. A total of 21.25% (17/80) was negative in both tests. The nested PCR (LnPCR) targeted to the gene associated with Leishmania SSUrRNA for sequencing were used to analyze 315 clinical samples from 80 Rattus norvegicus. Samples of 80 pieces of tail skin, 78 fragments of bone marrow, 78 blood samples and 79 fragments of spleen were subjected to the diagnosis and showed 17.46% (55/315) positive tissues where 10% (8 / 80) skin tail, 26.92% (21/78) blood, 30.76% (24/78) bone marrow and 2.53% (2 / 79) spleen. The infection rate of rodents was 36.25% (29/80) and 65.51% (19/29) of them had the parasite characterized as belonging to the Leishmania braziliensis. The results demonstrate the urbanization of the cycle of cutaneous leishmaniasis, typically rural and adaptability of the vector to the anthropogenic environments. The identification of natural infection by L. braziliensis in R. norvegicus is a significant indicator for zoonotic potential of this species and the maintenance of programs for its population control and health education are important measures in the control of leishmaniasis in the urban context where the environment is constantly modified