Infammatory response, parasite load and AgNOR expression in ear skin of symptomatic and asymptomatic leishmania (Leishmania) chagasi infected dogs

Abstract

The skin has an important role in the transmission of visceral leishmaniasis (VL) as the infection pathway in dogs. To better characterize the infammatory response of intact skin in VL, sixty infected dogs (30 symptomatic and 30 asymptomatic) and six non-infected controls were studied. Diagnosis of visceral leishmaniasis was confrmed by RIFI and ELISA; direct visualization of the parasite in bone marrow aspirate; imprints of popliteal lymph nodes, spleen, liver and skin; culture in NNN-phase liquid Schneider's medium; and PCR (performed only in the ear skin). Amastigote forms of the parasite in intact skin were found only in symptomatic dogs. Infammatory infltrates were observed in all groups, varying from intense and/or moderate in symptomatic to discrete and/or negligible in asymptomatic and control animals. Parasite load was associated with the intensity of the infammatory response and with clinical manifestations in canine visceral leishmaniasis. AgNOr as active transcription markers were expressed in infammatory cells and within apoptotic bodies in all groups, including controls, with no statistical diference. Therefore, cell activation and transcription do occur in both symptomatic and asymptomatic canine visceral leishmaniasis and may result in more necrosis and infammation or in apoptosis and less symptoms, depending on the parasite load.