Do feral pigs play an important role in New Zealand’s Tb problem?
Despite sometimes having a high prevalence of bovine tuberculosis (Tb), feral pigs are generally regarded as spillover end-hosts unable to sustain the disease in the absence of infection in other species. Although intra-specific transmission occurs in captivity (Ray et al.. 1972), transmission between feral pigs must be rare because there are few places in the world where Tb has persisted in feral pigs in the absence of infection in other species (Nugent et al. 2003a,b). The clearest evidence for end-host status is the decline in prevalence in pigs following the removal of infected cattle and buffalo from parts of the Northern Territory of Australia (McInerney et al. 1995). Countering this widespread belief, new evidence suggests Tb may have persisted in wild boar long isolated from livestock in Spain (Aranaz et al. 2004), and there is increasing suspicion that although not maintenance hosts in their own right, feral pigs do play some role as part of a wildlife complex in sustaining an
