Sometime between 1920 and 1960, the southern vole arrived arrived in the Russian settlements of Grumantbyen. They probably arrived as stowaways on ships bringing hay and straw to the animals there. With the mice probably came the parasite Echinococcus multilocularis. Foxes and dogs who eat infected mice are the hosts for the parasite.
"The reason why we are so interested in this parasite is that they can transmit from animals to humans," said Heidi Enemark, a veterinarian and parasite researcher for the Norwegian Veterinary Institute. "It is not a common infection, but it is serious, lifelong and difficult to treat."
The veterinary institute and the Norwegian Polar Institute are now determining whether the parasite exists in mice, foxes and dogs in and near Longyearbyen. The project is funded by the Svalbard Environmental Protection Fund. Enemark and Fredrik Samuelsson, who has local knowledge and a master's degree in parasitology, provided information about the project last week. They also supplied a questionnaire to dog owners about collecting dog poop for analysis.
"This has not been done previously." Enemark said. "There is a large block of dogs in the city, and it becoming larger and larger. There is a lot of contact between human and dogs. Therefore, it is important to get an overview of the potential infection pressures."
It is a tradition in Longyearbyen that dogs are dewormed twice a year. It protects against the parasite.
"Now we will also look at whether the two annual cycles is enough," Enemark said. "If infected pressures are high it may be that people should do deworming more often. It may also prove that this simply is not an issue because the dogs are on a leash and do not have the opportunity to catch mice."
Last week researchers gathered samples from 62 dogs. In addition to Echinococcus multilocularis, they will look for other parasites.
Anyone who wants can provide a stool sample from a dog until Nov. 1 at Svalbard Vet. Providers will also be required to fill out a short questionnaire.
"We are interested in getting as representative a sample as possible," Enemark said. "Yesterday we drove around the kennels, and we've gotten people with city dogs to provide stool samples to the veterinarian. We would like to have both. Infectious conditions may be different depending on whether the dogs are in the city or outside in kennels. The way dogs are used may also have something to say about the risk of infection."
Dogs and foxes that have the parasite will excrete eggs in the feces. The eggs can live a long time.
"We do not know how long they can survive in Arctic conditions, but they can in most cases survive throughout the summer period and presumably also under the snow in winter," Enemark said.
The veterinary institute will see if the parasite exists in foxes provided to the Norwegian Polar Institute after capture.
"It's been ten years since the prevalence has been checked in foxes," Enemark said. "We know that the incidence is highest at Grumant since the vole is the intermediate host."
Researchers will also study the mice. They are scheduled to return in November to set up traps.
"We will ask to set up mousetraps where there may be food leftovers, and therefore mice, including places such as the school, store and horse stable."
The researchers also encouraging people to set up mousetraps and deliver their catch to Svalbard Vet.
"People need not be afraid dealing with mice," Samuelsson said. "The parasite is not transmitted from mice to humans. It is only foxes and dogs that can be infected by eating mice."
Though there is a great danger of infection between animals and humans now, it takes about five to 15 years before symptoms of disease are first detected in humans.
"It's a little hidden infection because it takes so long before you discover that you are infected," Enemark said.
Echinococcus multilocularis does not exist on mainland Norway, but incidences are increasing elsewhere in Europe. Whether that is due to climate change or people traveling more remains unknown to scientists.
"There are probably many doctors who will say that the parasite is not so serious because there are so not many who are getting ill," Enemark said. "But those infected can die if they are not treated. If the disease is detected, it must be treated for life."
Should people be worried?
"No, we do not believe so at the present time," Enemark said "But it is a parasite that is so severe that one should have control of it. If it turns out that infestation pressure is high, we can make recommendations about what people should do. Initially, you should wash your hands when you have been in contact with dogs. It is important that this is not a scare campaign."
She expects that all samples will be analyzed and the results known in April. The researchers will then come to Longyearbyen to present the results.
No symptoms yet in Svalbard
Erik Krag Jenssen, chief physician at Longyearbyen Hospital, said he does not know of any people in Svalbard infected with the parasite in recent years.
"In other words, it is a rare disease and therefore there is hardly any reason to take special precautions beyond the following advice: good hygiene is, as always, the best protection against infection," Jenssen said. "Specific advice for areas with a high infection risk is boiling water from streams, using gloves when in contact with foxes or with dead animals in general, washing hands after any contact with foxes or exposed dogs, as well as washing hands before meals and after stays in vulnerable areas near Grumant."
He cites sources from the Norwegian Polar Institute and the veterinary institute stating a large number of people were checked for the disease in 1999. Two scientists, both of whom worked in at-risk areas, were found to have antibodies in their blood.
There is no official monitoring of the parasite in Svalbard.
Hilde Haug, section manager for the Norwegian Food Safety Authority in Troms and Svalbard, said monitoring programs by the agency are largely governed by European Union regulations.
"Monitoring programs we have are largely to show which animal diseases we do not have on the mainland," she said. "That is essential if we are to implement animal health requirements for the importation of animals from more illness-deprived areas. Since we know that there are parasites on Svalbard, one must takes precautions in relation to that. The main thing is that people are acting hygienic when they associate with animals."
Translated by Mark Sabbatini.