12 October 2011

2 minute read

The main culprits in the non-eradication of FMD in southern Africa are wild buffaloes.

African buffaloes are healthy carriers of the disease, and as such are a permanent source of infection for livestock around the region's many protected areas. The veterinary authorities primarily use two complementary methods to control the disease: installing physical barriers to separate buffaloes and livestock, and vaccinating livestock.

The combination of these two methods had given good results, but the disease has re-emerged throughout the region over the past decade or so.

To validate this assertion, CIRAD developed ways of assessing the efficacy of these methods and the risk of virus transmission between wildlife and livestock. The results were unequivocal.

The researchers involved recorded the main failings in maintenance of the veterinary barriers built to separate wildlife from livestock. The fences are mainly damaged by elephants, which are growing in numbers in southern Africa, by rural communities keen to access natural resources, and by annual flooding.

To improve their efficancy, the researchers suggested introducing regular checks on the fences and transferring fence management to rural communities.

In regards to vaccination, the protocol drawn up by the only vaccine manufacturer in the region is too expensive for most countries. Instead of the recommended five annual vaccinations, animals are given only two, in the hope that this will provide sufficient protection.

However, the study by CIRAD and its partners showed that even if the first vaccine dose was followed by a booster a month later, the antibodies triggered had all but disappeared four months later. This knowledge will help countries to make valid decisions about how much of the budget to be allocated to vaccination.

Lastly, infected zones are often rural zones bordering on protected areas, in which there are buffaloes that carry the FMD virus. Thousands of families live there, and the zones act as buffer zones between protected areas and areas in which cattle are produced for export.

The farmers concerned have little in the way of knowledge, but it is vital that they collaborate in applying disease surveillance measures. Moreover, since they live in zones near wild reservoirs that are thus seen as infected, they are excluded from both national and international markets.

It is therefore crucial to reverse the trend if we are to contribute to their development and make virus surveillance and control systems in the region more effective.