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A Joint Operation Centre (JOC) has been set up in Mamusa local municipality, North West, to control the spread of African swine fever (ASF), which threatens domestic and wild pig populations. The disease was identified in Ipelegeng and surrounding areas by the Agricultural Research Council (ARC) and Onderstepoort Veterinary Institute (OVI) in a communal pigsty.
Dr Langa Madyibi, local director of veterinary services, stated that after 162 pigs died in December, a local veterinarian investigated in January. Samples were taken from the site which involves 33 pig farmers, to confirm the diagnosis and trace genetic links to the 2016 outbreak. An action plan is in place to control the disease, including preventing the movement of pigs and products in and out of the ASF control zone. Contact between warthogs and domestic pigs must also be avoided to limit the disease’s spread.
A decline in cases
Dr Peter Evans, CEO of the South African Pork Producers’ Organisation (SAPPO), says that a national ASF working group, including state veterinarians, veterinarians from the Pig Veterinary Society and SAPPO, as well as other stakeholders, has been formed. The group found that ASF prevalence in South Africa is much lower than it was three years ago. He says although ASF remains present and is not confined to the control zone since 2017, the number of cases has decreased significantly. This decline is largely attributed to awareness campaigns aimed at small-scale farmers. SAPPO’s Facebook adviser, Zach, plays a key role in providing information on ASF transmission and prevention. He says that while ASF is likely to remain a concern, the country is managing it much better. The disease’s reduced occurrence in communal farming areas lowers the risk of it spreading to larger commercial farms. In the most recent North West outbreak, affected areas were quarantined and culling is not necessarily an option. So far, there have been only three ASF outbreaks on commercial farms – two in North West and one in Gauteng. ASF has not resurfaced since, with the last outbreak on a commercial farm occurring in 2021 in North West, from which valuable lessons were learned.
ASF vaccine development
Dr Evans explains that ASF became a global issue in 2019 when it spread to countries like China and Vietnam. Efforts have since focused on developing a vaccine, which was trialled in Vietnam 18 months ago. However, countries are still awaiting results on its effectiveness. A key challenge is that there are 25 ASF genotypes, with genotype 2 being the strain that spread to Asia. While a vaccine is being developed for genotype 2, it’s uncertain whether it will provide cross-protection against other genotypes.
In South Africa, both genotype 2 and some genotype 1 cases have been identified. Whether South Africa will consider vaccination in the future, depends on the development of an effective vaccine. Significant research will be needed before South Africa can determine if vaccination is a viable option. The ASF control zone covers the northern parts of North West, Mpumalanga, and the whole of Limpopo, based on the presence of ASF-positive warthogs that can transmit the virus to domestic pigs. However, warthogs outside the original control zone have also been found to carry the virus, which may lead to the eventual phasing out of the control zone, as ASF has now spread across all nine provinces over the last eight years.
The focus is shifting to managing ASF through education and awareness campaigns for farmers. Dr Evans highlights that farmers can prevent ASF by taking the right precautions, such as avoiding buying pigs from auctions or unregulated traders. He says with a significant decline in ASF cases, it’s clear that the message is spreading, and farmers are becoming more aware of the risks. Biosecurity, however, remains the most important measure for mitigating ASF risk. Regardless of farm size, adopting strong biosecurity practices is essential. If all pig farmers understand how ASF is transmitted and how to reduce infection risks, outbreaks could be minimised, potentially reducing cases to nearly zero. – Christal-Lize Muller, Plaas Media
For more information contact dr Peter Evans at peter@sappo.org.
