Norovirus, also known as winter vomiting bug, can spread quickly via person-to-person contact, contaminated surfaces or through the air. Its primary symptoms are diarrhoea, vomiting, and stomach pain.
“It began on Saturday night when we were called from a cabin where there were some people who had caught influenza. We picked up eight people at that point and that number has now increased,” Hordaland Red Cross information officer Kent Eivind Vorland told NRK.
Norway's tourist cabins (turisthytter) are communal facilities intended to provide food and shelter to mountaineers, climbers and hikers. They are generally not accessible by road.
“13 people have now been transported out from the tourist cabin in Sandhaug using scooters… there are five snowmobiles and five people in action… [in total] 29 people have been evacuated due to stomach problems,” Vorland said.
Norway's tourist association (Den Norske Turistforening, DNT) also confirmed the evacuations, according to NRK's report.
“This is something that catches very easily. People can feel well, but still carry the virus from one cabin to the next. And there are many who go from one cabin to another during the Easter holidays, so it could potentially spread,” Vorland added.
Doctor Torbjørn Bjotveit in nearby Eidfjord, who has been in contact with the Red Cross, told newspaper Bergens Tidende that norovirus was a likely culprit.
“This virus is very contagious. It is not dangerous, but very annoying,” he said.
DNT said it was working on keeping the sickness from spreading.
“It is sad to see our guests at cabins getting sick. We are doing what we can to get it under control. Those that are unwell are being isolated in their own rooms and given access to their own toilets,” DNT Oslo's manager Henning Hoff Wikborg told NRK.
The tourist association has also taken steps to ensure hygiene control in the communal cabin facilities, according to the report.