Swine fever in Sweden is spreading. Norway offers bounty for reporting sick and dead wild boars
African swine fever has not yet spread into Norway. The Norwegian Veterinary Institute is now urging Norwegians to report any injured, sick or dead wild boar they see.
“These are exciting times,” says Carl Andreas Grøntvedt at the Norwegian Veterinary Institute.
He is a veterinary researcher and swine expert working on a wild boar and domestic surveillance programme.
The Veterinary Institute has been commissioned by the Norwegian Food Safety Authority to monitor and diagnose African swine fever should it make its way into Norway.
African swine fever is a serious and contagious viral disease that affects wild boars and domestic pigs, but it does not infect humans or other animals.
“So far, African swine fever has not been detected in any samples in Norway,” says Grøntvedt.
The Veterinary Institute coordinates closely with other authorities and regularly updates the risk assessment for the disease, Grøntvedt says.
Sick wild boar count at 18 in Sweden
Sweden has detected 18 cases of African swine fever in recent weeks.
Last week, 800 square kilometres northwest of Stockholm were cordoned off. Fifty domestic pigs had to be killed.
On 15 September, Norwegian Minister of Agriculture Geir Pollestad (Sp) met with the Norwegian Agrarian Association, Norsvin, the Norwegian Forest Owners’ Federation, Norskog and the Norwegian Association of Hunters and Anglers on the swine fever issue.
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“Norway needs to decrease the wild boar population to prevent the spread of swine fever, and we are considering measures to accomplish this,” Geir Pollestad told the Norwegian News Agency (NTB).
You might also like the podcast from the Norwegian Veterinary Institute (in Norwegian): Afrikansk svinepest – en konstant dyrehelsetrussel også i Norge (African swine fever – a constant threat to animal health in Norway as well).
No idea how many wild boars are in Norway
The wild boar is an undesirable and relatively recent species in Norway, having migrated from Sweden.
Norway’s aim is to have as few wild boars as possible in the smallest possible area.
The Norwegian Institute for Nature Research (NINA) is working to gain an overview of the wild boar population numbers, their distribution and how they behave in Norway.
They also want to find out how the boars spread and what they live on.
“We know very little about wild boars in Norway, how many wild boars are here, or how they use and move around the landscape,” says Jørgen Rosvold, the assistant research director at NINA.
“Wild boars are often difficult to spot for most people, even when a lot of them are present in an area. They’re usually really shy animals and are most active at dusk and at night,” Rosvold says.
Norway felled 60 more wild boar last season
The last hunting season saw 425 wild boars killed in Norway from 2022 to 2023, an increase of 60 animals from the previous year. The hunting season runs from 1 April to 31 March of the following year.
These data are taken from statistics on deer family species and wild boar published by Statistics Norway on 1 September.
Most wild boar are felled in Aremark and Halden municipalities along the Swedish border in the south of Norway. In the 2021/2022 hunting season, 79 percent of all wild boar caught were shot in these two municipalities.
Swine fever a concern for many years already
Norway has already established a system to monitor wild boar health and African swine fever.
“We have focused intently on African swine fever for many years,” says Grøntvedt.
Already in 2014, the disease invaded populations of wild boar in Poland and the Baltic countries following a large outbreak in Georgia several years earlier.
“The disease has spread relatively slowly among wild boar, like a smouldering fire,” says the researcher, “at a speed of about one to three kilometres per month.”
Many samples taken from dead wild boar
“We’re now receiving many samples of felled wild boar,” says Grøntvedt.
The analyses are part of the wild boar health monitoring programme.
The samples are sent in from hunters who trap wild boar, for which they receive remuneration from the Norwegian Food Safety Authority.
“We receive samples from 60 to 70 percent of the wild boars killed, so the support for this effort is high,” he says.
People are also encouraged to report to the Norwegian Food Safety Authority if they see injured, sick or dead wild boar. This is important for detecting serious diseases like African swine fever early.
“People are paid NOK 3000 for doing this,” says Grøntvedt.
The Norwegian Food Safety Authority then follows up on the notification and ensures that samples are taken.
The hunters send samples of faeces, blood and tissue from the animals. Test kits are sent out in advance to relevant municipalities and to the Norwegian Association of Hunters and Anglers.
Humans can spread infection
The disease is very difficult to combat in wild boar populations. So difficult, in fact, that only the Czech Republic and Belgium have been successful in containing this outbreak.
But the virus doesn't just spread between animals.
People and human activity constitute another route of infection, by bringing it from abroad to wild boars in Norwegian nature or to domesticated pigs.
“That’s why it is so important to follow the authorities' infection control advice to prevent the spread of the disease,” emphasizes Grøntvedt.
Game camera monitoring
New technology has proven very useful to monitor wild boar populations since their nocturnal habits make them so difficult to see.
NINA uses hunting statistics, GPS tagging, genetic surveys and game cameras to gather data.
They operate a large network of wildlife cameras in Norway, and several of these can capture wild boar activity.
At Nina.no you can see an overview of the cameras. You can select for wild boar (Velg art: Villsvin): Game camera
Greatest occurrence in former Østfold county
The wild boars in Norway have so far mainly been observed along the Swedish border. Most are taken in the former county of Østfold.
“The greatest prevalence of wild boar in Norway are found in Aremark and Halden municipalities. But they have also been hunted in the interior and observed as far north as Verdal in northern Trøndelag county,” Rosvold says.
NINA carries out genetic analyses of the submitted wild boar samples to find out where they come from, as well as how they spread and where they find food.
“Wild boar that come over from Sweden now present a potential risk factor for spreading African swine fever.”
Contaminated food waste?
Swedish wild boars may not pose the greatest threat of the disease, however.
“The nearest known spread of this disease in Europe is far away, so the infection has probably not spread naturally,” Rosvold says.
He emphasizes that currently the main hypothesis is that infection has occurred more randomly, such as through the animals being in contact with infected food waste or slaughterhouse waste from further south in Europe.
In an article in Nationen, a Norwegian newspaper focusing on agriculture and rural districts, researchers at NINA are now calling for funding to create a more solid knowledge base about wild boar in Norway.
We have to know what kind of animals we have in Norway and how they behave in order to implement helpful and targeted measures,” says Rosvold.
You might like to hear the Norwegian podcast that NINA has created on the topic: Villsvin - hva gjør de i Norge? (Wild boar – what are they doing in Norway?)
Northwest of Stockholm
The latest – as well as previous – discoveries of sick wild boars were made in the area around Fagersta in sscentral Sweden, north of Stockholm.
Sweden is now receiving help from experts from several other European countries, including Belgium and the Czech Republic, to stop the outbreak of Asian swine fever.
Several countries have now stopped importing Swedish pork.
The Norwegian Food Safety Authority has not made any changes regarding Norway’s import of pork from Sweden.
Familiarize yourself with Swedish rules
“The country where the meat is sold is responsible for the meat being infection-free,” says Grøntvedt.
In general, Norwegians who are traveling in Sweden should stay up to date on restrictions and advice at Jordbruksverket.se (The Swedish Board of Agriculture).
Grøntvedt also encourages people to follow the Norwegian Food Safety Authority guidelines.
Population must be reduced
“Everyone agrees that the wild boar population has to decrease, and we want to build on the work that has been done, but these measures need to be intensified and strengthened. We also need to consider new measures,” Pollestad tells NTB.
Pollestad has asked the Norwegian Food Safety Authority to assess a strengthened action plan against wild boar and new proposals for how to reduce the wild boar population in Norway, according to a press release by Pollestad.
From Halden to Elverum
The wild boar population is mainly dispersed along the Swedish border, from Halden in the south to Elverum in the north. The greatest number of wild boars observed on the game cameras are in the municipalities of Halden and Aremark.
Single individuals can be expected to occur across large parts of southern Norway. These are usually single males.
The wild boar population in the core areas of Aremark and Halden is stable, and Hedmark shows a decline, according to NINA's overall data in 2022.
The data are based on game cameras, observations, fall game data on wild boar in the Deer Game Register, and where wild boars have been shot.
You might also like to read the Norwegian article: For å hindre pesten må vi vite hva svina gjør i Norge. (To prevent the virus, we need to know what the wild boar are doing in Norway).
(First published in Nationen)
References:
J. Odden et al: Bestandsovervåking av villsvin. Status 2022 (Monitoring of wild boar. Status 2022). Norwegian Institute for Nature Research, 2023.
Handlingsplan mot villsvin 2020 - 2024 (Action plan against wild boar 2020 – 2024). Norwegian Environment Agency/Food Safety Authority, 14 November 2019.
Additions on 21 September:
Podcast from the Norwegian Veterinary Institute (in Norwegian): Afrikansk svinepest konstant dyrehelsetrussel også i Norge. (African swine fever – a constant animal health threat in Norway as well).
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Read the Norwegian version of this article at forskning.no
