Dozens of dogs in Norway have recently been hit by a mysterious and at times fatal illness, raising concerns among dog owners who have been told to limit contacts between canines.

Axar.az reports citing Telegraph that some 200 dogs have displayed the same symptoms - bloody diarrhea and vomit, intense fatigue - in recent weeks and around 25 of them have died, Norway's Veterinary Institute said on Monday.

The number is an estimate, as the Scandinavian country does not have a national register.

"This doesn't necessarily mean that it's the same illness, as there are lots of illnesses that can lead to these kinds of symptoms in dogs," Veterinary Institute spokesman Asle Haukaas told said.

Autopsies on 10 dogs revealed in each case a severe intestinal infection and five of them had "abnormally elevated levels" of two bacteria, Clostridium perfringens and Providencia alcalifaciens.

The illness has been observed mostly in greater Oslo, but there have been a few cases in other parts of the country.