The "Chronic wasting diesease" (CWD) deals with Norway's reindeer. The responsible Ministry of Agriculture is now having 2,000 animals killed to prevent the spread of the disease.
Five years in quarantine
The herd of 2,000 animals to die comprises 6% of the total deer population in Norway. After the mass killing, the region where the animals live is said to be quarantined for five years to stop the disease from breaking out again.
Other deer are also affected
CWD has been diagnosed since 1967. The first symptoms appear two years after the infection with the proteins: the saliva flows, the animals lose weight and appear apathetic. They die a few months later. The disease is fatal not only to reindeer, but also to other deer.
No danger to people
The brain disease is similar to BSE in cattle. In contrast to BSE and some diseases of exotic pets, there are no signs that CWD is transmitted to humans.
The pathogen remains for years
Infected animals excrete the infectious prions - with saliva, faeces and urine. So they quickly infect other deer. Feeding places are also a paradise for the pathogen. The prions stay in the environment for years, and since many deer live in groups, the risk of infection is enormous.
Long known in North America
Until recently Norway was not affected by the disease, so far the CWD has broken out in America. At times, 40% of all deer were affected in Wyoming.
Biologists discover CWD
In March last year, biologists discovered a sick reindeer cub in Nordfjella. The dead animal was examined by veterinarians in Oslo and found CWD.
The prions were like those in America.
How did the plague come to Norway?
It is unclear how the brain disease reached Norway. Perhaps the reindeer became infected with deer urine, which hunters in the United States bottled to attract deer and which the Norwegian hunter poured into the environment. Or travelers to the USA dragged the proteins along with their clothing.
However, there is no evidence of infection by animals in wildlife parks or zoos that came to Norway from the USA.
However, a more spontaneous outbreak is more likely. Prion diseases can develop in an animal's brain when a protein folds incorrectly and mutates from this form into an infectious one. The Norwegian veterinarians suspect that this is how the disease developed.
Elk also affected?
In May 2016, a hunter found two infected moose near Trondheim. However, it is probably not the same, but a related disease, because reindeer and elk have different prions.
There is hardly any disease risk in moose
Moose are loners - in contrast to reindeer. Therefore, the risk of infection is low. In addition, the two sick moose were old, which, according to Norwegian biologists, indicates a spontaneous development of the disease. The country's moose are therefore only under close surveillance, but are not killed.
Reindeer are more exposed to a CWD epidemic than any other deer. Among the deer, they are the ones who live in the largest herds. Therefore, the Norwegian group of experts decided to take the drastic measure of killing the entire herd in Nordfjella.
Until the killing, the reindeer are isolated in the 2000 square meter area: no reindeer may leave the area, no new one is added. This is relatively easy to implement because the region is surrounded by roads that the animals rarely cross.
Quarantine until 2022
The area is to remain rent-free until 2022. Then faecal samples are examined and it is determined whether the pathogens are still infectious. Michael Samuel of the University of Wisconsin is familiar with CWD and says, "Chances are they will get the problem under control."
It is not yet the all-clear. Nobody knows that the dangerous proteins have also taken root in other parts of Norway. Nationwide, 20,000 tissue samples from reindeer will therefore be examined in the next hunting season.
The EU is alarmed
CWD can infect not only reindeer, but also red deer, fallow deer and roe deer. That is why the EU supervisory authority Efsa recommends monitoring European deer for three years in seven countries.
Endangered species endangered?
For rare deer species in game parks such as the Pater Davids deer, Bukhara deer or the Mesopotamian fallow deer, the risk of infection is extremely low - they could only theoretically become infected via proteins on people's clothing. But such an outbreak would affect endangered species.
The information comes from the magazine Science. Further information: www.aaas.org (Dr. Utz Anhalt)