Relationship between parasitemia and leukogram in Trypanosoma evansi infected cats

Abstract

Trypanosoma evansi is a protozoan which causes trypanosomosis in livestock in many countries of Southeast Asia, Africa and South America. We chose to use cats in our study due to the facility to handle the animals and the lack of studies involving the trypanosomosis in this species. The aim of this study was to analyze the leukogram of domestic cats experimentally infected with T. evansi and its correlation to the parasitemia. Thirteen animals were divided into two groups. Seven animals were infected with T. evansi and six were used as negative control. Parasitemia was estimated daily by microscopic examination of smears. Blood samples for leukogram were collected at days 0, 7, 21, 35 and 49. The parasitemia peak was recorded at day five post-inoculation. Thereafter, irregular waves of parasitemia were observed, ranging from zero to three trypomastigotes per microscopic field. Increased number of total leukocytes (day 49), monocytes (days 7, 35 and 49), segmented (day 49) and nonsegmented neuthrophils (day 35), and decreased number of lymphocytes and eosinophils (days 21, 35 and 49) were observed (P < 0.05). Cats infected with T. evansi have leukocytosis, neutrophilia, monocytosis, lymphopenia and eosinopenia. However, no relationship between parasitemia peaks and white blood cells was observed, except by the monocytes in day 7.