Cluster of mysterious hepatitis cases in US children prompts CDC health alert

U.S. doctors should be on the lookout for unexplained liver inflammation in children, the Centers for Disease Control and Prevention (CDC) advised Thursday (April 21). Affected children should be screened to see if they've been infected with an adenovirus, a type of virus that's been flagged as a potential cause of the condition, the agency noted.

The recommendation comes after health officials identified a cluster of children with both liver inflammation, also called hepatitis, and adenovirus infections in Alabama, according to the CDC. Two additional cases of pediatric hepatitis have been reported in North Carolina, although it wasn't noted if these were also associated with adenovirus infections, according to NBC News. Similar cases of unexplained hepatitis have also been reported in Europe, including in the United Kingdom, where some of the affected children tested positive for adenovirus, the CDC said.

In Alabama, five historically healthy children were hospitalized in November 2021 after developing significant liver injuries due to hepatitis, according to the Health Alert Network (HAN) health advisory issued by the CDC. Three of the five children developed acute liver failure, wherein the organ loses function very rapidly. All five of the children tested positive for an adenovirus, which belongs to a family of viruses that can cause the common cold, pink eye and bronchitis, among other illnesses. 

These initial five cases prompted the hospital to launch a wider investigation, and the doctors identified four additional children who'd been treated for hepatitis between October 2021 and February 2022; all of these children tested positive for adenovirus, as well. 

Samples taken from five of the nine children were run through a thorough genetic analysis, which revealed that all of the children were specifically infected with adenovirus type 41. This virus typically causes inflammation of the stomach or intestines, known as acute gastroenteritis, in children, according to the CDC. 

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Gastroenteritis typically causes diarrhea, vomiting and fever, and "it can often be accompanied by respiratory symptoms," the HAN health advisory stated. Although adenovirus type 41 has previously been linked with hepatitis in children with weakened immune systems, this particular virus "is not known to be a cause of hepatitis in otherwise healthy children," the advisory said.

Having identified these nine cases, "a possible association between pediatric hepatitis and adenovirus infection is currently under investigation," the advisory stated. U.S. doctors who might encounter children with hepatitis of unknown cause should consider testing such children for adenovirus and report the cases to state public health authorities and to the CDC, the advisory said.

U.K. health officials recently launched their own investigation into dozens of pediatric hepatitis cases that have cropped up in the country in recent months, some of which progressed to liver failure, Live Science previously reported. All of the affected children tested negative for hepatitis viruses (hepatitis A, B, C, D and E). But some tested positive for adenoviruses, and some tested positive for SARS-CoV-2, the virus that causes COVID-19. 

None of the children in the U.S. cluster have tested positive for COVID-19, according to the HAN health advisory.

U.K. officials also suspect that an adenovirus might be the underlying cause of the cases there, but investigations are ongoing, they wrote in a report published April 14 in the journal Eurosurveillance. 

Beyond the U.K. and the U.S., similar hepatitis cases have now been reported in Spain, Denmark and the Netherlands, Science reported.

Symptoms of hepatitis include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, light-colored stools, joint pain and jaundice, meaning yellowing of the skin or the whites of the eyes, according to the advisory. Potential complications of hepatitis include liver failure and death, and liver transplants are typically used to treat end-stage liver failure, according to Stanford Children's Health. Among the affected children in the U.S., two required liver transplants, according to the CDC advisory, and several of the affected kids in Europe also required liver transplants, Live Science previously reported.

Affected children often have unusually high levels of liver enzymes — namely aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) — in their blood. Because of this, the CDC is asking doctors and state public health authorities to report any cases of children having remarkably high AST or ALT levels that happened between October 2021 and now.

Originally published on Live Science.