Field and laboratory investigations of African swine fever in bushpigs at the livestock-wildlife interface in Uganda
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African swine fever (ASF) virus - the only member of the Asfarviridae family - is a DNA virus affecting swine and able to cause devastating economic losses. Despite worldwide efforts, the search for both a vaccine and treatment has yet been unsuccessful. The virus has managed to spread out of the African continent to other countries on several occasions. Since 2007, when it was introduced in the Caucasus, Russian Federation and Eastern Europe, the disease seems to be spreading without control and is now considered to be endemic in many parts of Russian Federation and Eastern Europe, imposing high risk for the European Union pig industry. Thus, ASF represents an international tangible threat to the pig industry.
Mortality rates associated to ASF in the domestic pig and wild boar (Sus scrofa) vary from 60 to 100%, whereas African wild pigs such as the warthog (Phacochoerus spp.) and the bushpig (Potamochoerus larvatus) are asymptomatic carriers. The virus can also be maintained and transmitted by ticks from the Ornithodoros species complex, which act as a reservoir. Unlike warthogs, which seem to only transmit the virus through tick vectors, experimental evidence suggests that bushpigs can transmit ASF virus by direct contact to susceptible domestic pigs. However, being an elusive nocturnal species, the level of interaction and potential risk for ASF transmission from bushpig to domestic pig has not received extensive attention.
With this in mind, the overall objective of this project will be to apply a molecular ecological approach to understand the role of the bush pig in the complex epidemiology of ASFV at the wildlife-livestock interface. More specifically we want to:
- Monitor movements of wild and domestic pigs to understand the behaviour and possible interactions possibly related to transmission of ASF;
- Assess the prevalence of ASFV in wild pig populations, with focus on the bushpig, in an area with on-going or recent outbreaks of ASF, and correlate findings to the spatial distribution of domestic pigs with that of wild pigs (i.e. in a gradient from the national park to community land) to understand the possible direction of ASFV spread;
- Assess genetic relationship between ASF viruses detected in wild reservoirs (with focus on the bushpig) and those detected during ASF outbreaks in domestic pigs in the area, to improve our understanding of routes and direction of spread.
- To train local veterinarians under MAAIF through the Makerere, SLU/SVA and ASF-Uganda network in ASF surveillance and early diagnosis, preparedness and disease prevention.
- To raise awareness and help the rural communities at the livestock-wildlife interface to prevent the emergence of ASF within their community.
- To strengthen local and international scientific collaboration to improve animal disease investigations.
The generation of this information will contribute significantly to effective ASF disease control strategies in this era of emerging and re-emerging infections, given the increasing livestock-wildlife interactions. In the long run this will also contribute to improved livelihoods of the rural communities living in the area through improved animal production and sustainable management of natural resources.