Assessing the impact of East Coast Fever immunisation by the infection and treatment method in Tanzanian pastoralist systems

Abstract

A field trial was carried out in a Maasai homestead to assess the impact of East Coast Fever (ECF) immunisation by the infection and treatment method (ITM) with the Muguga Cocktail on the occurrence of this disease in Tanzanian pastoralist systems. These data were further used in partial budgeting and decision analysis to evaluate and compare the value of the control strategy. Overall, ITM was shown to be a cost-effective control option. While one ECF case was registered in the immunised group, 24 cases occurred amongst non-immunised calves. A significant negative association between immunisation and ECF cases occurrence was observed (p≤0.001). ECF mortality rate was also lower in the immunised group. However, as anti-theilerial treatment was given to all diseased calves, no significant negative association between immunisation and ECF mortality was found. Both groups showed an overall similar immunological pattern with high and increasing percentages of seropositive calves throughout the study. This, combined with the temporal distribution of cases in the non-immunised group, suggested the establishment of endemic stability. Furthermore, the economic analysis showed that ITM generated a profit estimated to be 7250 TZS (1 USD=1300 TZS) per vaccinated calf, and demonstrated that it was a better control measure than natural infection and subsequent treatment.