Wisconsin is the fourth state to announce that it is investigating cases of hepatitis or hepatitis, which do not appear to be caused by any of the usual suspects such as hepatitis A, B, C or D.
Alabama reported nine cases in its cohort, including two children who required liver transplants. Illinois has reported three cases, including one that required a liver transplant, and North Carolina says it has two that meet that definition.
The majority of cases, 114, have been reported in the UK. There have been 13 cases in Spain, 12 in Israel, six in Denmark, less than five in Ireland, four in the Netherlands, four in Italy, two in Norway, two in France, one in Romania and one in Belgium, according to the World Health Organization. .
Adenoviruses make up a large family of viruses that can spread from person to person, causing a range of illnesses including the common cold and gastroenteritis. It is rarely reported as a cause of acute hepatitis in otherwise healthy people.
But these hepatitis cases come as the spread of adenovirus has escalated in recent months, along with other common viruses that have surged with the end of Covid-19 prevention measures and behaviors that have kept most germs at bay.
After dropping dramatically during the pandemic, documented cases of adenovirus have come back and are now at levels higher than what the UK experienced before Covid-19.
Although investigations are on adenovirus, it is still not clear how it can cause hepatitis. Experts say the virus may be just one factor that leads to these cases when it occurs along with something else.
CNN’s Michael Needleman contributed to this report.