Theories emerge for mysterious liver illnesses in children

NEW YORK (AP) — Health officials remain perplexed by mysterious cases of severe liver damage in hundreds of young children around the world.

The best available evidence points to a fairly common stomach bug that isn't known to cause liver problems in otherwise healthy kids. That virus was detected in the the blood of stricken children but — oddly — it has not been found in their diseased livers.

“There's a lot of things that don't make sense,” said Eric Kremer, a virus researcher at the Institute of Molecular Genetics of Montpellier, in France.

As health officials in more than a dozen countries look into the mystery, they are asking:

— Has there been some surge in the stomach bug — called adenovirus 41 — that is causing more cases of a previously undetected problem?

— Are children more susceptible due to pandemic-related lockdowns that sheltered them from the viruses kids usually experience?

— Is there some mutated version of the adenovirus causing this? Or some other not-yet-identified germ, drug or toxin?

— Is it some kind of haywire immune system reaction set off by a past COVID-19 infection and a later invasion by some other virus?

The U.S. Centers for Disease Control and Prevention and investigators around the globe are trying to sort out what's going on.

The illnesses are considered rare. CDC officials last week said they are now looking into 180 possible cases across the U.S. Most of the children were hospitalized, at least 15 required liver transplants and six died.

More than 20 other countries have reported hundreds more cases in total, though the largest numbers have been in the U.K. and U.S.

Symptoms of hepatitis — or inflammation of the liver — include fever, fatigue, loss of appetite, nausea, vomiting,...