Nine children in Sweden have fallen ill with suspected acute hepatitis without any apparent cause, the country's Public Health Agency has said.

"It is very unusual but does occur that a child suffers from acute hepatitis with an unknown cause. The Swedish Public Health Agency is investigating whether the cases we see now represent an increase in acute hepatitis with an unknown cause or not," state epidemiologist Anders Lindblom said in a press release.

All nine children fell ill between November to April and caregivers have now been urged to be vigilant should they encounter similar cases. Besides jaundice, the nine cases have also had symptoms such as vomiting, diarrhea, pale stools, and nausea, the Xinhua news agency reported.

Similar cases of hepatitis without an apparent cause have recently been reported from several countries, such as the US, the UK, and Denmark.

The Swedish Public Health Agency has reported the Swedish cases to the European Center for Disease Prevention and Control (ECDC) to be included in an ongoing investigation to find out whether there is a common denominator.

According to the ECDC, laboratory tests have excluded viral hepatitis types A, B, C, D, and E in all cases. A large proportion of the reported cases in the UK and some other countries have tested positive for adenovirus. (AA/IANS)