Causing up to 100 per cent mortality in previously unaffected animals, African Swine Fever (ASF) is a devastating disease of pigs. Endemic across much of Africa, the disease poses a wider threat to global food security, particularly in East Asia, where at least 50 per cent of the protein consumed is pork, much of it produced through small to medium-scale ‘backyard’ enterprises.
Current control methods are by diagnosis and slaughter but this approach is difficult, expensive and often not practical for smallholder farmers. To better understand the complexities of the disease, a consortium of research and development organisations* from around the world is implementing a range of approaches across Africa.
New strains add risk
Whilst there are currently no formal economic estimates of the overall losses to ASF in Africa, an outbreak in Madagascar in 1998 killed half the country’s pig population (250,000 animals). During the last year, ASF outbreaks have also been reported in North Cameroon where over 100,000 animals may have been lost to the disease. In October 2010, the World Organisation for Animal Health (OIE) received notification of the first ASF outbreak in Chad.
In addition, there is evidence that different strains of virus causing the disease are spreading within the continent. In 2010, a highly lethal genetic type of the virus, previously known only from East Africa, was detected in the Republic of Congo. Beyond Africa, the disease is endemic in Sardinia as well as in the Caucasus and Southern Russia, posing a risk to the EU and parts of Eastern Europe.
The epidemiology of ASF is complex, involving wild pigs, particularly warthogs, and soft ticks, in eastern and southern Africa. In west and central Africa transmission is believed to be mostly by direct transfer of the virus between domestic pigs, or via infected offal contaminating feed.
African swine fever virus (ASFV), the causative agent, is a highly stable DNA virus that can survive under a wide range of temperatures and pH levels. DNA viruses tend to be much more stable than RNA viruses – the main cause of many important human diseases – and can be more easily disseminated over broad geographic areas through the movement of infected swine or contaminated pork products.
Read the whole article in the latest edition of New Agriculturist: http://www.new-ag.info/en/focus/focusItem.php?a=2281
Related articles also worth reading:
Credits: Article authors, Edward Okoth & Richard Bishop of ILRI and Larelle McMillan of CSIRO, the production of the article was supported by CSIRO-AusAID, image, Flickr by Stevie Mann/ILRI
For more information about this project email Richard Bishop at r.bishop(at)cgiar.org