The best available evidence points to a fairly common stomach disease that is not known to cause liver problems in otherwise healthy children. This virus has been detected in the blood of affected children but, oddly enough, not in their diseased livers.
“There are a lot of things that don’t make sense,” said Eric Kremer, a virus researcher at the Montpellier Institute of Molecular Genetics in France.
As health officials in more than a dozen countries get to the bottom of the mystery, they ask:
– Has there been a surge in the stomach bug – dubbed adenovirus 41 – causing more cases of a previously undiscovered problem?
– Are children more vulnerable due to pandemic lockdowns that protected them from the viruses that children are normally exposed to?
– Is there a mutated version of the adenovirus that is causing this? Or another yet unidentified germ, drug, or toxin?
– Is it some kind of crazy immune system reaction triggered by previous COVID-19 infection and later invasion by another virus?
MORE: CDC is investigating more than 100 cases of unexplained hepatitis in children, including 5 deaths
The US Centers for Disease Control and Prevention and investigators around the world are trying to figure out what’s going on.
The diseases are considered rare. CDC officials said last week they are now investigating 180 possible cases in the United States. 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, although most cases have occurred in the UK and US
Symptoms of hepatitis — or liver inflammation — include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, light-colored stools, joint pain, and jaundice.
The extent of the problem only became clear last month, although disease investigators say they have been working on the mystery for months. It’s been insanely difficult to pinpoint a cause, experts say.
Traditional causes of liver inflammation in otherwise healthy children — the viruses known as hepatitis A, B, C, D, and E — didn’t show up in tests. In addition, the children came from different places and there seemed to be no common encounters.
What emerged was adenovirus 41. More than half of US cases have tested positive for adenovirus, of which there are dozens of variants. In a small number of samples tested to determine what type of adenovirus was present, adenovirus 41 appeared each time.
The fact that adenovirus keeps popping up strengthens the case for it playing a role, but it’s unclear how, said Dr. Jay Butler, CDC associate director for infectious diseases, told The Associated Press.
Many adenoviruses are associated with cold symptoms such as fever, sore throat and conjunctivitis. Some versions — including adenovirus 41 — can trigger other problems, including inflammation in the stomach and intestines. Adenoviruses have previously been associated with hepatitis in children, but mostly in children with compromised immune systems.
Recent genetic analyzes have found no evidence that a single new mutant version of the virus is responsible, said Dr. Umesh Parashar, leader of the CDC group focused on viral enteric diseases.
Adenovirus infections are not systematically tracked in the US, so it is not clear if there has been a recent increase in viral activity. In fact, adenoviruses are so common that researchers aren’t sure what to make of their presence in these cases.
“If we start testing everyone for the adenovirus, they’re going to find so many kids” who have it, said Dr. Heli Bhatt, a pediatric gastroenterologist who treated two Minnesota children with liver problems.
One was a child who came to us with liver failure almost five months ago. Doctors couldn’t figure out why. Unfortunately, “having no cause is something that happens,” Bhatt said. Experts estimate that about a third of cases of acute liver failure remain unexplained.
Bhatt said the second child she saw fell ill last month. By that time, health officials had flagged cases, and she and other doctors had begun going back and reviewing unexplained illnesses since October.
In fact, many of the cases added to the list in recent weeks were not recent illnesses, but previous ones that have been reassessed. About 10% of US cases occurred in May, Butler said. The rate appears to have been relatively flat since the fall, he added.
It’s possible doctors are just discovering a phenomenon that’s been around for years, some scientists said.
The COVID-19 vaccination was ruled out because “the vast majority of these children are unvaccinated,” Butler explained.
But previous infection with the coronavirus itself could be a factor, scientists say.
The CDC recently estimated that as of February, 75% of US children were infected.
Just 10 to 15 percent of children with the mysterious hepatitis had COVID-19, according to nasal swab tests taken when they checked into a hospital, health officials say.
However, investigators are wondering about previous coronavirus infections. It’s possible coronavirus particles lurking in the gut play a role, said Petter Brodin, a pediatric immunologist at Imperial College London.
In an article earlier this month in the medical journal Lancet, Brodin and another scientist suggested that a combination of ongoing coronavirus and an adenovirus infection could trigger a liver-damaging immune system response.
“I think it’s an unfortunate combination of circumstances that could explain this,” Brodin told the AP.
Butler said researchers have seen complex reactions like this before, and investigators are discussing ways to better test the hypothesis.
He said it was “not outside the realm of plausibility at all”.
A preprint study from Case Western Reserve University, which is yet to be peer-reviewed, suggested that children with COVID-19 were at a significantly higher risk of liver damage.
dr Markus Buchfellner, a pediatric infectious diseases physician at the University of Alabama at Birmingham, was involved in identifying the first US cases in the fall.
The diseases are “strange” and worrying, he said. Six months later, “we don’t really know what we’re dealing with.”
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https://abc7.com/children-hepatitis-liver-disease-kids-outbreak/11885845/ How do children get hepatitis? A mysterious liver disease could have links to the gastrointestinal virus COVID, researchers say