Leishmania spp. amastigotes in lymph nodes, bone marrow, spleen, skin and blood of naturally infected dogs

Abstract

Visceral leishmaniasis is an anthropozoonosis caused by the protozoa of the genus Leishmania and is transmitted by sandflies of the genus Lutzomyia. Dogs are considered the major reservoirs of parasite, being important for the maintence of the cycle of the disease. In recent years, the disease has been spreading throughout many regions of Brazil, with a growing and worrying prevalence in Mato Grosso do Sul, mainly in Campo Grande. The diagnosis of canine leishmaniasis should be done based on clinical signs, visualization of the parasite in biopsy samples from bone marrow and lymph nodes, serologic tests such as indirect immunofluorescence (IFA), ELISA, molecular methods such as Polymerase Chain Reaction (PCR) or even tissue culture. The purpose of this work was to observe the presence of amastigote forms of Leishmania spp. In samples obtained through biopsy of lymph nodes, bone marrow, spleen, peripheral blood and skin from ELISA and IFA positive dogs. Among the 32 animals studied, the presence of Leishmania forms was observed in all studied tissues of 32 dogs. It was also verified the presence of inclusions suggestive of Ehrlichia canis in 12 dogs, from witch 4 dos were negative for Leishmania spp. In cytological examinations, reinforcing the need for better confirming methods for canine leishmaniasis.