Control of TB in wildlife by oral BCG vaccination

Abstract

Evaluation of: Tompkins DM, Ramsey DS, Cross ML et al. Oral vaccination reduces the incidence of tuberculosis in free-living brushtail possums. Proc. Biol. Sci. 276(1669), 2987–2995 (2009).Tuberculosis caused by Mycobacterium bovis is present in many wild animal populations throughout the world. The disease can have a significant economic impact when the wild animal species is a reservoir of infection for domestic animals. It can pose a zoonotic threat for those who come in contact with infected animals, be they wild or domesticated. To date, strategies for dealing with TB in wildlife have been limited; physical separation of wild from domestic animals or culling of infected populations can help to reduce the spread of infection, but culling is not an option with species of high conservation value. Vaccination of animals with the bacillus Calmette–Guérin (BCG) vaccine has long been considered an attractive strategy for combating the disease. However, its widespread use in the wild has been constrained pending the development of a suitable delivery system. In the paper under evaluation, Tompkins and colleagues in New Zealand have shown that oral vaccination with BCG can protect wild brushtail possums against natural infection with M. bovis. This highly significant finding paves the way towards incorporation of wildlife vaccination into bovine TB eradication programs worldwide.