STOCKHOLM: Nine children in Sweden have fallen ill with suspected acute hepatitis without any apparent cause, the Scandinavian nation's public health agency said on Tuesday. 'It is very unusual, but [it] 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 news release. All nine children fell ill between last November and April, and caregivers have been urged to be vigilant should they encounter similar cases. Similar hepatitis cases have recently been reported in several countries, including the United States, United Kingdom and Denmark. The health agency has reported Sweden's cases to the European Center for Disease Prevention and Control to be included in an ongoing investigation to find if there is a common denominator among them.