African swine fever (AHS) is a highly contagious virus that only affects pigs; in the event of an outbreak, strict disease control measures are implemented. It is subject to a requirement for international notification and trade restrictions on pork. The spread of African swine fever is producing significant economic difficulties for the pig farming industry.

The Estonian University of Life Sciences (EMÜ) researchers' involvement in the Põlvamaa pig farm case is to help the Food and Agriculture Board in determining when and how the disease reached the pig farm. They are also looking into whether the virus could have spread from there. Based on this information, the government can devise additional measures to prevent the virus' spread. A team of researchers from the University of Life Sciences will visit the farm and the animals, as well as analyze laboratory data, to do this.

While it is relatively simple to limit the spread of illness in domestic pigs by quickly eliminating outbreaks, eliminating infection from wild pig populations has proven incredibly challenging thus far. Because this is a lethal disease, the spread of infection among feral animals will result in a quick reduction in their population. We saw this in Estonia between 2015 and 2018, but that does not mean that the virus, along with the wild boars, vanished completely. In Estonia, plague outbreaks have been identified in wild boars since 2020.

African swine fever is moving into new parts of Europe, fast spreading in the Balkans and Italy, and gradually expanding its range in central European countries. However, in Latvia and Lithuania, a full-fledged second plague outbreak in wild boars has been recorded, which has been accompanied by outbreaks in domestic population.

The disease can reach Estonia from other countries via both humans and wild boars. Human transmission occurs mostly through products made from infected domestic pigs or wild boars, which are either fed to domestic pigs as food waste or wind up in the wild, where wild boars consume them. This is especially likely when rules are not followed: a hunted wild boar is not tested in a laboratory; a diseased domestic pig is not reported to authorities and is slaughtered for food.

Given that the spread of swine fever in Europe is accelerating, the likelihood of such scenarios also increases. Hence the responsibility and opportunity for everyone to control the spread of the disease: not to bring pork and wild boar products and products from their home country with them when traveling. It is also important to avoid buying and receiving these products from dubious sources, both abroad and at home. A farm-raised pig may be very tasty, but it can cause economic disaster for another pig farmer, not to mention terrible suffering for thousands of wild or domestic animals in another country.

However, Estonia's situation on the swine fever front has so far remained relatively good compared to its neighbors. It has been two years since the last outbreak in our home farm. There have also been only a few outbreaks in wild boars in recent years in counties near the Russian border.

Virus strain differs

The virus strain in Põlva and Võru counties differs from those found so far in Estonia, so it is suspected that this is due to a new entry of the virus into Estonian territory. The geographical location suggests that it probably came from Russia. Recent weeks have shown that the virus is still circulating in the wild boar colony in Põlva-Võru, from where it most likely spread to a nearby domestic farm. The final answer will be given to us soon by molecular typing.

However, the outbreak detected on a home farm in Võru county is thought to be of Latvian origin. The outbreak occurred just 10 kilometers from the country's southern border and far enough away from the former Põlva-Võru colony bordering Russia. The infection has now also been detected in wild boar population in the area.

However, until there is an effective vaccine to control African swine fever in wild boar populations, any outbreak must be eradicated in advance to prevent the virus from taking hold. To do this, we need to work very well together to ensure that any suspected outbreaks of disease continue to be reported quickly to the Estonian Agriculture and Food Board. Secondly, there is an urgent need to eradicate the disease and the only way to do that is to kill the whole herd.

Estonian pig farmers are responsible and the cooperation, communication and resolution of the situation so far has been swift and smooth. This has been helped by the fact that there are rather few small pig farms in Estonia. Most of our pigs are in large pig farms, where it is easier to prevent the spread of the disease.

However, people who go berry picking and mushroom picking in the forest in Põlva and Võru counties should be very careful not to get into a car or go berry picking and mushroom picking in another area with the same clothes they wore in the forest.

The African swine fever virus is very persistent in the environment and can be transmitted through clothing and footwear, apparently also in forest environments. To avoid this, clothes and footwear should be washed properly after a walk in the woods, and shoes should be disinfected. Disinfectants left over from the Covid-19 pandemic period are well suited for this purpose.

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