Modelling the Societal Burden of Anthrax in Cattle in the Western Province of Zambia Using a Modification of Disability Adjusted Life Years

Anthrax, which is a naturally occurring zoonotic disease caused by the bacterium Bacillus anthracis, has been endemic in Western Zambia. This paper estimated the societal burden of anthrax on cattle using Productivity Adjusted Life Years (PALYs) among cattle farmers in the Western Province of Zambia. A quantitative cross-sectional study design was used to collect data from cattle farmers in Mongu, Nalolo and Limulunga districts of Western Zambia. The Disability-Adjusted Life Years (DALY) model for human populations was modified and adapted to the animal population model, PALYs, to estimate the societal burden of animal diseases. The integral calculator was used to estimate the societal disease burden of anthrax using PALY equations in three categories: PALYs without discounting and age weighting, PALYs with only discounting, and PALYs with discounting and age weighting. The results showed that anthrax affected the quality of life years lived by animals significantly due to years lost due to disability (YLD) and years lost due to premature death (YLL). A cow, bull and ox lost about 34%, 39% and 37% of productivity years of its life span due to anthrax. This shows that a bull lost most years of productivity, seconded by an ox and, lastly, a cow. Anthrax further caused a total loss of 459,280.90 PALYs in the three districts. The quality of life is improved, and productivity losses are reduced to almost 0% for all three types of animals by introducing effective anthrax control measures in the absence of other adverse health conditions. Anthrax negatively affected livestock production due to significant loss of healthy years of life and loss of quality of life. Since bulls lost most of the productivity years of their life span, we argue that transportation, draught power, sells as well, as socio status were the most affected as these are usually performed by the bull, the most productive. Therefore, it is important to minimise the loss of cattle productivity through morbidity and mortality. Different intervention programmes for the same disease can be compared in cost-effective analysis using PALYs as one of the tools. Therefore, the societal burden of diseases should also be applied on top of other existing methods used to assess the impact of diseases on animals to enable policymakers to have a complete and comprehensive picture of the impact.