Clinico-pathological studies in cattle experimentally infected with Taenia saginata eggs

Abstract

Calves 1-2 months old were experimentally infected with eggs of Taenia saginata and clinical and haematological deviations, development and distribution of cysticerci and pathological changes were recorded. The calves infected with 5 000, 10 000 or 50 000 eggs showed an increase in pulse and respiratory rates. The animals that received 50 000 eggs had significantly increased pulse (p < 0.05) and respiratory rates (p < 0.005). The symptoms were more severe in young, 30-day-old calves infected with 50 000 eggs. Haemoglobin concentration, haematocrit values and red blood cell count decreased, but white blood cell count increased slightly. Lymphocytes and eosinophils also increased up to 88 % and 14 % (p < 0.05), respectively. Most of the cysticerci were not fully formed 1 month post-infection, but at 2 months the cysts were fully mature and at 4 months, some cysts had degenerated. There was no uniform pattern of distribution of cysticerci in the body of infected calves, but the most commonly affected sites were masseter and heart muscles, followed by diaphragm, tongue and other skeletal muscles. The maximum concentration of 8-14 cysticerci per 10 g of tissue was recorded in masseter muscles and heart. The affected parts revealed tissue reactions that included pressure atrophy, necrosis and fibrosis. Microscopically, the lesions comprised infiltration with lymphocytes, plasma cells, eosinophils and macrophages, fibrosis, necrosis and calcification. The tissue reaction was severe in calves infected with 50 000 eggs. The severity of clinical signs, haematological and pathological changes depended mostly on the age of the animals and dose of infection.