HATTIESBURG, Miss. (WHLT) – A disturbing spike in hepatitis cases has occurred among children under the age of six in the United States and around the world.

The Centers for Disease Control and Prevention (CDC) is investigating the cause of the sudden liver disease because the origin is unknown.

Despite more than 20 other countries reporting cases, doctors said they know the disease is not spreading at school. If the disease was spreading at schools, there would be more cases.

Doctors said parents should watch their kids closely for signs of the illness. However, they said there’s no need to panic about the pediatric liver disease because the illness is still considered rare.