Epidemiology and control of east coast fever in Zambia. A field trial with traditionally managed Sanga cattle.

Abstract

The main objective of the reported field trial was to compare different East Coast Fever (ECF) control strategies for their efficacy, effect on cattle productivity and cost-effectiveness. Five strategies were tested in groups of traditionally managed Sanga cattle over a period of 2.5 years. Two groups were under intensive tick control, one group immunized by the infection and treatment method and the other non-immunized. Two groups were under no tick control, one group immunized and the other non-immunized (the control group). The fifth group was under strategic tick control and was immunized against ECF. All ECF control methods tested significantly reduced mortality, but no marked differences to the control group were seen in other production parameters. No difference in mortality was observed between animals protected from ECF by immunization or by tick control. The most cost-effective method of controlling the disease was by immunization. A financial analysis showed that under the prevailing conditions the break-even price for immunization ranged from US$21.5 to US$25.7 depending of the proportion of reactors. The carrier state induced by immunization did not lead to a persistent high incidence of ECF in non-immunized animals using the same grazing area.