Reviewing the role of vultures at the human-wildlife-livestock disease interface

Abstract

Vultures are a key component of an effective scavenger guild and have evolved a number of adaptations that allow them to locate and dispose of carcasses quickly and efficiently. The continuing decline of African vultures is threatening the stability of the African scavenger guild, which may result in increased carcass decomposition times and thus, more rapid development of pathogenic bacteria. The absence of competitive regulation by these apex scavengers may also result in changes in the composition of the vertebrate scavenger guild, with an increase in mammalian scavengers giving rise to increased contact rates at carcasses, which may increase the risk of viral disease transmission to humans, livestock, and other wildlife. Although the economic value of vultures in terms of the sanitation services they provide has been evaluated, their contribution to the economics of human health and veterinary care remains to be quantified. Efforts to do so are hampered by lack of data, as well as a number of confounding factors that may mask causality, such as improved disease prevention and surveillance systems. However, the circumstantial nature of the link between vultures and disease prevention should not deter efforts to conserve them, as their regulation of mammalian scavengers and the sanitation services they provide place them firmly within the sphere of One Health, thereby warranting their urgent protection. The restoration of vulture populations and the ecosystem services they provide will benefit the welfare of all humans, but particularly those who are most vulnerable to economic instability and the spillover of disease at the human-wildlife-livestock interface.