A total of 28 cases of hepatitis A infection has been reported over the last few months in Norway, where this disease is said to be rare, the Norwegian news Agency NTB reported Saturday, quoting public health officials.

Health authorities, who were worried by the growing number of hepatitis A cases, are working to determine whether the sick people are infected from a common source.

In almost half of the cases, the patients were found to have infected with hepatitis A virus while travelling abroad,

The remaining half got infected in Norway, which was described as a rare occurrence.

Last year there was an outbreak of hepatitis A in the Nordic countries, which was believed to be most likely caused by eating imported frozen berries.

Norwegian health authorities suspect the new outbreak in Norway is also caused by eating contaminated food.

The Norwegian Food Safety Authority is now cooperating with the Public Health agencies to carry out an investigation into if it is the same type of hepatitis A virus which has caused the outbreak.

Infection of hepatitis A virus can also occur through person-to-person contact.

Symptoms of hepatitis include fever, nausea, vomiting, abdominal pain and jaundice.