Relação de carga parasitária com parâmetros reológicos e imunológicos na leishmaniose visceral canina

Abstract

Visceral leishmaniasis is a zoonosis caused by a protozoan of the family Trypanosomatidae, genus Leishmania. In Brazil, Leishmania chagasi is the agent of the disease, transmitted to humans and animals mainly by phlebotomines, Lutzomyia longipalpis. The disease is characterized by clinical manifestations ranging from mild to moderate to severe. Anemia, uremia, hyperproteinemia and hyperglobulinemia are common clinical and pathological changes in canine visceral leishmaniasis (LVC). Several studies have confirmed the importance of the immune response in the pathogenesis of LVC. It is necessary to take into account the existence of a balanced control between pro-inflammatory and anti-inflammatory cytokines in determining the severity of the disease. Studies demonstrate the existence of genetic predisposition in the occurrence and recurrence of the disease. The diagnosis of visceral leishmaniasis is based on clinical exams, epidemiological and laboratory data. The aim of this study was to correlate hematological and rheological parameters, as well as to associate the parasite load with serum levels of cytokines (IL-2, IL-4, IL-6, IL10, IFN-γ, TNF-α and IL-17 ) in dogs with visceral leishmaniasis. Blood samples were collected from 62 dogs, 31 of which were reagent sera for visceral leishmaniasis and 31 healthy (control) sera. It was observed that there was an increase in the number of erythrocytes, in the hemoglobin concentration and in the percentage of hematocrit. Regarding the rheological behavior of the blood, there was a correlation between the viscosity and the number of erythrocytes between the control and LVC samples. The results of this study demonstrated that there was an evolution of the severity of the lesions from stage I to stage III. Serum concentrations of the cytokines IL-4, IL-6 TNF-α, and immunoglobulin G were higher in serum of dogs with LVC when compared to the control group. In the present study there was no correlation between antibody levels with IL-6 production. Even so, increased IL-6 production has been associated with elevated antibody levels. TNF-α is important in the control of parasitic growth, associated with the evolution of the disease.