Traditional disease control in animals has focused on attempting to reduce transmission by aiming preventative treatments at all, or the majority of, a population. Such controls assume that all individuals are as likely as each other to become infected and to transmit to others. However, recent research has suggested that this is not the case: the number of infections caused by an individual is skewed, with some members of a group playing little or no part in disease transmission, whilst others will infect many. These latter individuals have become known as the ‘superspreaders’ (Lloyd-Smith et al. 2005). Previous work showed such variation in the spread of tuberculosis (TB) in meerkats. Meerkats are susceptible to TB and the disease is a problem in the Kalahari’s resident population. Grooming and aggressive behaviours have been shown to be factors in the spread of the disease, and those individuals that engage more in these activities therefore are likely to have an unbalanced involvement in disease spread (Drewe et al. 2011). Although it is hypothesised that targeting control at individuals based upon their roles in transmission, this has not been tested empirically.
The aim of our research is to investigate whether an understanding of susceptibilities and social networks in meerkats can be used to selectively target individuals for interventions, and thus enhance disease control. To achieve this aim, our research objectives are to:
- Develop and trial methods to improve the accuracy of TB diagnosis in meerkats in a field setting in order to improve the reliability of the research results
- Establish the effectiveness of BCG (bacille Calmette-Guerin) vaccination against TB in meerkats
- Test the effect of vaccination strategies based on meerkat contact networks against their ability to reduce disease incidence in a free-living population
Fieldwork to obtain a background infection level and trial novel diagnostics began in late 2013. Ongoing analysis of these results will inform a field trial of a range of vaccination strategies and controls in distinct social groupings of meerkats in the Kalahari. Group level infection status will be monitored to measure the levels of transmission.
This project is funded by the RVC, Friends of the Kalahari Meerkat Project and the University of Cambridge.
Drewe, J.A., Eames, K.T.D., Madden, J.R. and Pearce, G.P. (2011) Integrating contact network structure into tuberculosis epidemiology in meerkats in South Africa: implications for control. Preventive Veterinary Medicine 101: 113-120.
Lloyd-Smith, J.O., Schreiber, S.J., Kopp, P.E. and Getz, W.M. (2005) Superspreading and the effect of individual variation on disease emergence. Nature 438: 355-359.