獣医科学と技術

Impacts of Trypanosoma vivax on Experimentally Infected Calves and Goats in Bishoftu, Ethiopia

Abstract

Fasige Getahun, Aynalem Mandefro and Hailegebrael Bedada

Four female calves aged of 1 year to 1 year and 4 months which weighing 86-100 kg and three male goats weighing 22-31 kg and ages of less than one year were included in the study. All experimental animals were infected intravenously with 1 ml (concentrated) blood containing the wild strain of T. vivax brought from Gibe valley. Fresh blood sample of each animal was collected directly from the jugular vein for 84 days in two days interval. The mean PCV was 34%, 33%, 35.5% and 33.25% respectively, for week one, week two, three and week four before inoculation for calves and 32.8%, 34.2%, and 35.8% for goats. The mean PCV started decreasing between 4-6 days post inoculation for all calves to 21.5+1.1% and then sharply decreased to 13+0.5% in day 13-17 post inoculation. Between days 19-24 post inoculation the mean PCV was increased to 21+2.2 and decreased to 14.6+1.14 between 26-35 days post inoculation. Thereafter the PCV decreased continually and attained the severely lowest value (10.5+0.7) between 66-78 days post inoculation. For goats the mean PCV decreased to 20+0.08% by day 6 post inoculation and then drop down in PCV attained its lowest (15+.03%) by day 14 post inoculation. Thereafter throughout the course of the disease the mean PCV makes up and down waves till the second lowest mean PCV was recorded at day 37 post inoculation. The lowest PCV was beyond 37 days post inoculation for goats but it was beyond 66 days post inoculation for calves. The wave of up and downs was almost similar in two species even though the numbers vary. All infected calves and goats similarly developed progressive neutropenia, an initial lymphocytosis, monocytosis and eosinophilia. In general as the course of infection increased severe pan leukopenia was observed and this could cause immunosuppression which intern could be due to reduced myelopoiesis for both species (the exact number of leukocytes vary for calves and goats). In general neutropenia and monocytosis continues for longer period than other leukocytes and these leukocytes if studied and amalgamated with other factors might help in diagnosis of animal trypanosomiasis. The weight loss was progressive for calves and goats and as the course increased loss was worsened in both species.