Control of BTB in Free-Ranging Wildlife

While the long-term goal of eradicating BTB from domestic cattle has been achieved in many developed countries, it is unattainable in free-ranging wildlife populations, and very challenging in cattle, also in developed countries, in an environment where there is a coexistent wildlife maintenance host of the infection (Bengis et al.

The choice of a suitable strategy for the control of BTB in wildlife depends on the primary conservation objectives for a particular ecosystem. African conservationists are faced with difficult choices and few options since they have an obligation to protect the species that host the pathogen, but they also have the responsibility of minimizing the risk of transmission of the disease to domestic cattle, other livestock, and humans at the interface. Additionally, they must also consider the potentially devastating impact on maintenance and spillover species, particularly when dealing with rare and endangered species.

Currently, M. bovis infection is not actively controlled in most affected African wildlife areas. In Southern Africa, fencing is used as a way of limiting the movement of BTB-infected animals (Jori et al. 2011), but flooding, elephant, and human activities disrupt them allowing BTB-infected animals to cross the interface at will. Game-deterrent fences are reasonably effective in restricting the movement of some animals, but a number of wildlife species including maintenance hosts of BTB, such as warthogs and kudus, cross intact fences at will either by jumping across them or by burrowing beneath them (Michel et al. 2006).

Control measures for BTB in free-ranging wildlife populations based on long­term interventions such as periodic mass capture followed by tuberculin testing and removal of positive animals can effectively reduce the prevalence of BTB and hence the infection pressure in the maintenance population in smaller conservation areas such as the Hluhluwe-iMfolozi Park (South Africa). Reduction in the prevalence rate reduces the risk of transmission to other wildlife species, and the possibility of spillback to cattle (Michel et al. 2015).

To effectively implement management strategies in wildlife populations, the BTB status of the infected population and neighboring domestic cattle should be moni­tored to gauge the impact of the control measures (Hlokwe et al. 2016).

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