TAMPA, Fla. (WFLA) — Wisconsin health officials are investigating whether a child’s death was caused by an unexplained outbreak of liver disease in children.

The Wisconsin Department of Health Services issued an alert Wednesday, saying it was investigating four cases of acute hepatitis and adenovirus infection in children, including one death. One of the children required a liver transplant.

Hepatitis is an inflammation of the liver that can be caused by a variety of infectious viruses and noninfectious agents, including drugs, toxins and certain medical conditions, according to the World Health Organization’s website. It can cause swelling and damage to the liver.

Adenoviruses are common viruses spread from an infected person to others. They can cause common cold or flu-like symptoms, a fever and sore throat, according to the US Centers for Disease Control and Prevention website.

The CDC previously issued a health advisory urging doctors to look out for cases of hepatitis in children with adenovirus infection. Around 190 cases have been reported in children around the world, the CDC said Tuesday, the majority (114) being in the United Kingdom.

Wisconsin is one of four US states investigating such cases. In Alabama, there were nine cases, including two children who required liver transplants. Illinois had three cases, with one child requiring a transplant and North Carolina reported two additional cases.

There is no link between the cases and COVID-19 vaccines, WHO said in a statement provided to Reuters.