Assessment of risk of introduction of Echinococcus multilocularis to mainland Norway and risk to human health
Report no: 2012: 06
The Norwegian Scientific Committee for Food Safety (VKM) considers it likely that the tapeworm Echinococcus multilocularis (EM) will be imported to the Norwegian mainland, perhaps within the next 10 years.
VKM suggests that the Norwegian population may have greater likelihood of exposure to EM than other European populations, due to its strong traditions for outdoor activities, such as hunting and berry picking. However, VKM also points out that even in countries with endemic EM, human infection is rare.
This conclusion is presented in a risk assessment performed by VKM on its own initiative. The risk assessment was prompted by detection of these tapeworms in four red foxes in three different locations in southern Sweden, one of which was only 65 km from the Norwegian border. EM is endemic in many European countries, its incidence is increasing, and areas of endemicity are expanding.
EM is a small tapeworm that usually lives in the intestine of foxes and dogs. It is of public health significance, as humans may act as intermediate hosts if they ingest EM eggs, either through contaminated foods or water, or from contact with infected final hosts or their faeces. Human infection is rare, but can be fatal in untreated persons.
Likely import routes
The most likely route for EM to reach the Norwegian mainland is probably by the high numbers of pets crossing the border between Sweden and Norway, and the paucity of checks regarding compliance with treatment legislation. Appropriate controls may reduce this likelihood.
It is estimated that between 70 000 to 120 000 red foxes live in Norway. Under current monitoring conditions, EM will probably only be detected once the prevalence in red foxes exceeds one per cent.
VKM suggests that if EM is identified early enough after introduction, it might be possible to avoid its establishment in Norway, and / or to limit the region of endemicity. However, this depends on adequate detection techniques and sufficient monitoring.
VKM considers it unlikely that EM will be imported to Norway via contaminated berries, fruits, mushrooms, or other produce.