Study on chronic wasting disease in cervids close to completion – the disease has not been detected in Finland


<div>CWD or Chronic Wasting Disease in cervids belongs to the TSE group (Transmissible Spongiform Encephalopathy) of dangerous diseases occurring in both animals and humans. Typical for the disease is deterioration of the central nervous system and a long incubation period. </div>

The survey was carried out in co-operation with hunters
CWD has caused significant economic losses to deer farming and hunting in the areas where it occurs in the United States and Canada and has initiated large studies and defence measures. For this reason the European Commission ordered each member state to survey the TSE situation in cervids in their area. In Finland the study has targeted white-tailed deer, of which 600 samples had to be collected from animals over 18 months of age. The reason for this is that the species is especially sensitive to the disease and the fact that Finland’s white-tailed deer population is unique in Europe. The disease has not been detected in the 550 samples analysed so far, neither have any symptoms suggesting the disease been observed in white-tailed deer.

Chronic Wasting Disease
CWD belongs to the same group as BSE (Bovine Spongiform Encephalopathy), or the so-called mad cow disease in cattle. However, BSE has never been detected in cervids, even though it is known that they have been exposed to feed contaminated by BSE material in Great Britain in the 1980's.

CWD can be transmitted both to cervids in the wild and farmed cervids and it has been detected in mule deer, white-tailed deer, red deer and elk. The pathogen is a transformed prion or a prion, which is very resistant to external conditions. An animal with CWD loses weight and its behaviour changes. Salivating and difficulties in swallowing are typical symptoms. As the disease advances the animal wastes away and severe problems with balance become evident. The disease will always lead to the death of the animal.

The transmission route of the disease has not been fully clarified
The most likely transmission route of the disease is considered to be both direct transmission between the mother and the calf and indirect transmission via a contaminated environment. Feeding stations for game are believed to contribute to the spread of the disease.

So far there are no indications that CWD might spread to humans. But so little is yet known about the disease, that in certain states of the USA detailed protective guidelines have been given for the handling of meat from cervid game animals before the completion of the testing results, and in Canada it is obligatory to test the animals before the meat is released for sale.

For more information, please contact:
Researcher Sauli Laaksonen, Fish and Wildlife Health Research Unit,
tel. 02077 24905, sauli.laaksonen
Senior Researcher Hannele Tapiovaara, Evira, Veterinary Virology Research Unit,
tel. 02077 24589, hannele.tapiovaara

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