Mark Sisson/FLPA

Pictures of a cute pet raccoon dog called Tanu went viral on Twitter last week. Meanwhile, its wild relatives have been “going viral” in a more destructive way among Europe’s wildlife. And worryingly, they harbour high levels of parasites that can infect people, some lethally.

Raccoon dogs (Nyctereutes procyonoides), with their luxurious fur and pointy faces, resemble raccoons, but are in fact distant relatives of foxes in the canid family.


These animals are native to East Asia. However, about 9,000 were released by Soviet biologists 80 years ago into western parts of the former Soviet Union to be hunted for their fur, says PA Åhlén of the Swedish Association for Hunting and Wildlife Management, who leads the effort to eradicate them in Sweden.

Raccoon dogs have since spread west as far as Germany and have been sighted in France and Italy. They move rapidly and reproduce prolifically. In Finland, a million cubs are born each year, says Åhlén.

And they pose a big threat to amphibian populations. There is now “not a single toad or frog in southernmost Finland”, says Åhlén. Ground-nesting birds are also at risk.

Reservoir for infection

Now it seems that raccoon dogs may also be an overlooked wild reservoir for parasites that affect humans.

The diseases they carry present a “considerable public health risk”, say scientists led by Urmas Saarma at the University of Tartu in Estonia. Saarma’s team found nine zoonotic parasites among the carcasses of 250 raccoon dogs they examined in Estonia, bringing the total number they have been found to harbour across Europe to 19.

In Estonia, the most common were the hookworm Uncinaria stenocephala and the flatworm Alaria alata. Of most concern, however, is that four carried the fox tapeworm Echinococcus multilocularis, which can be fatal if untreated in humans after a silent incubation period of up to 20 years.

Estonia is the sixth country in Europe where this infection has been reported in raccoon dogs, says Saarma. He says however that the risk of them spreading it to humans is not very high because of the lack of direct contact.

But Heidi Enemark, a senior researcher at the Norwegian Veterinary Institute, says that hotspots have been found in Germany, where the animals have a much higher incidence of the tapeworm than in Estonia.

The fear is that an influx of raccoon dogs raises the general levels of the parasite in nature, says Åhlén, thus increasing the likelihood of humans catching it when picking fruit, taking their dogs out or hunting.

The raccoon dogs themselves seem to be trying to rid themselves of the parasites through self-medication. Saarma’s team found that the more infected the animals they examined were, the more grass and other plant material they had ingested – which might have helped to dislodge the parasites.

Into the wild

Åhlén says that a fashion for owning raccoon dogs, fuelled by popular characters such as Tanu, will inevitably lead to more escapes into the wild.

Facebook groups for owners of raccoon dogs in the UK number hundreds of members, says Åhlén.

In the UK, which is still believed to be free from wild raccoon dogs, the pet trade is considered the most likely route of entry. Indeed, an owner in Cornwall posted his raccoon dog as missing on a website for lost pets this week.

“There’s a high risk that Great Britain already has an emerging population,” says Åhlén. “And that, I can promise you, will not be good for its amphibian life.”

Enemark agrees. “In an island country like the UK, you should do anything within your power to keep them out,” he says.

Journal reference: Veterinary Parasitology, DOI: 10.1016/j.vetpar.2016.01.020

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