The U.S. Centers for Disease Control and Prevention is investigating mysterious cases of hepatitis among young children.
In 109 cases since October being investigated, five children died and several more needed a liver transplant. About half of the children had confirmed cases of an adenovirus, a common class of viruses that can cause congestion and flulike symptoms.
Doctors don't yet know the cause of these cases but are researching whether there may be a link between hepatitis and adenovirus, as well as other potential contributing factors.
The vast majority of children who developed hepatitis recovered. Still, severe hepatitis is rare among children, which is why doctors and the CDC have urged parents to be alert.
Here's what to know:
Q. What is hepatitis?
A. Hepatitis is the medical term to describe liver inflammation. Hepatitis occurs on a spectrum, meaning patients can experience minor or severe inflammation, said Salwa Sulieman, a pediatric infectious disease specialist at Nemours Children's Health.
Q. What causes hepatitis?
A. Hepatitis has infectious, meaning it stems from a virus, and non-infectious causes.
Hepatitis viruses A, B, and C are the most common causes of viral hepatitis in the U.S.: