We study the epidemiology of tuberculosis in wild meerkats using a combination of fieldwork, laboratory investigations and long-term data analysis.
Meerkats (Suricata suricatta) are social mammals that live in groups. A potential disadvantage of being social is that infectious diseases are more likely to spread. Tuberculosis (TB: a bacterial infection) was first detected in wild meerkats in southern Africa in the late 1990s. Since 2005 we have conducted research in the Kalahari Desert to better understand the epidemiology of this disease in meerkats, asking such questions as:
- What exactly causes TB in meerkats?
- How does it spread?
- Who infects whom?
- How accurate are diagnostic tests?
- Does vaccination help reduce the amount of disease?
- What are the long-term impacts of TB on the population?
In addition to gaining knowledge of the epidemiology of TB in meerkats, insights from our research are helping inform how TB is tackled in other species around the world.
We are revealing the epidemiology of TB
Many things can affect who gets infected with a disease and what the outcome is. Over the past 15 years we have conducted fine-scale studies of the risk factors for TB in wild meerkats, including using social networks to reveal transmission between individuals within a group, to environmental factors affect TB-related mortality in meerkat groups. We have been able to do this thanks to the ongoing and regular collection of behaviour and interaction data by researchers at the Kalahari Meerkat Project. We combine this with clinical results from our diagnostic testing of the meerkats, to determine the factors which affect the risk and consequences of TB to the individual, group and population.
We have conducted a vaccination trial
Individuals vary in their potential to both acquire and transmit infections. Some may be superspreaders which means they are responsible for infecting a disproportionately high number of others. Conversely, most individuals infect very few others. We conducted a vaccination trial against TB in the meerkats using BCG vaccine. Our results showed that targeting vaccination at specific meerkats can be effective at reducing TB within their social groups (compared to unvaccinated control groups), even when most of the meerkats remain unvaccinated. This finding is exciting and has broad relevance to many other species: it may be particularly useful for wildlife diseases where you often want to (or are only able to) do the fewest interventions possible.
Our research is ongoing
We continue to study the epidemiology of TB in meerkats and other species in the region.
We discovered a new species
Our understanding of TB in meerkats has come a long way over the last 20 years. We now know it to be caused by a novel bacterium that is epidemiologically and genetically unique. In 2013, we named this new species Mycobacterium suricattae (Mycobacterium = the bacteria that cause TB; suricate = meerkat). In 2015 we published the whole genome sequence of this pathogen, which revealed it is closely related to—but distinct from—a bacterium found in hyraxes (dassies) which live in the same region. This suggests that the bacteria co-evolved in southern Africa and meerkats did not become infected from cattle or even people, as was previously thought.
We have improved how TB is diagnosed
Accurate diagnosis of TB in animals is difficult. It is even harder when you are dealing with a free-living wild animal that doesn’t particularly want to be tested. The main problem is that most diagnostic tests for TB are not very sensitive and so false negative results are common. Over the years we have evaluated many different types of TB test in the meerkat population, and we have contributed to the development of a new diagnostic test for use in meerkats. This research has shown how good the tests are and which combination of tests gives the most useful information. We have then used these results to better understand the epidemiology of TB in meerkats; knowledge which has also provided insights into how the disease spreads and can be diagnosed in other social-living species in other countries—such as in European badgers (Meles meles) in Great Britain.
News/In The Media
Our research was featured in the Animal Planet/BBC series Meerkat Manor Dr Julian Drewe appeared in some behind-the-scenes episodes of the popular Meerkat Manor TV series. He was interviewed about his research into TB in the meerkat population and filmed conducting fieldwork in the Kalahari Desert.