Cases of hepatitis, an inflammation of the liver, in children who were otherwise healthy have recently been reported in over 25 countries. The Centers for Disease Control and Prevention issued a warning to health care professionals to look for signs for this mysterious hepatitis with an unknown cause that mostly affects children under the age of 5. The European Center for Disease Prevention and Control released a report the week of May 11 that stated there have been approximately 450 cases of the rare liver condition worldwide. The European health agency said of those cases, 109 were reported in the United States and five deaths in the U.S. were reportedly due to the liver condition. 

According to the CDC, more than 90% of the cases in the United States resulted in hospitalizations and 14% had received liver transplants. None of the children were hospitalized due to current SARS-CoV-2 infection, the virus that causes COVID-19, the report said. 

Dr. Joseph DiNorcia is an associate professor of surgery at the Icahn School of Medicine at Mount Sinai in New York City and a transplant surgeon at the Recanati/Miller Transplantation Institute at Mount Sinai Hospital who spoke with Fox News about this pediatric hepatitis that has parents concerned and experts perplexed. 

mother holding child's hand who fever patients have IV tube.

Nearly all of the U.S. cases of hepatitis in children resulted in hospitalizations, according to the CDC. (iStock, File)

DiNorcia, who is also the surgical director of pediatric liver transplantation at Mount Sinai, explained to Fox News that when the liver is inflamed, the liver’s many roles get affected. 

The liver transplant surgeon said parents should look for the following in their children if they suspect this liver condition: 

 - Fever

 - Fatigue

 - Gastrointestinal symptoms such as loss of appetite, nausea, vomiting, and abdominal pain

 - Jaundice (yellowing of the eyes and skin)

 - Dark urine or light-colored stool

 - Muscle and joint pain

If your child shows any of the above signs or symptoms DiNorcia told Fox News it's important to seek immediate medical care. He said a blood test could detect hepatitis if it shows elevated liver enzymes and abnormal measures of liver function.

There are several hypotheses about the cause of this mysterious liver disease. The CDC said there is an investigation into the possible association between the pediatric hepatitis and an adenovirus infection after many of the children diagnosed with the rare liver condition tested positive for an adenovirus, according to the CDC report.

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According to health experts, adenoviruses are viruses that cause a variety of symptoms similar to the flu and common cold that range from sore throat to fever, stomach pain, nausea, diarrhea, pink eye (conjunctivitis), and bronchitis or in some cases, a bladder infection. Experts say it is typically contracted by personal contact.  

When asked if there is a link between the cases of hepatitis and the current COVID-19 pandemic, DiNorcia told Fox News, "There is no known connection to COVID. Of the known cases of hepatitis, there has been no evidence of active COVID infection."

The liver transplant specialist further explained other potential hypotheses. "Perhaps prior COVID infection made these children more susceptible to hepatitis. Or that the hepatitis is a result of a multi-system inflammatory syndrome in children (MIS-C) that happens after COVID infection." He also hypothesized, "or maybe sheltering during the pandemic has caused an abnormally robust and irregular immune response to whatever may be causing the hepatitis in children." DiNorcia said health professionals are investigating if toxins, infectious agents, or environmental exposures may be causing the hepatitis. 

child doctor medical care

An expert said there's no connection to COVID-19 vaccines. (iStock, File)

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When asked if there was a connection to COVID-19 vaccines, DiNorcia said, "No. Most of the cases are occurring in children ages 2-5 who have not received the vaccine."

If a child is diagnosed with this form of hepatitis, the physician said that initial treatment includes supportive care in a hospital setting to help the liver recover. However, the doctor warned, "If the hepatitis progresses to liver failure, the only treatment is liver transplantation."

More than two dozen countries have reported cases of the rare pediatric hepatitis. (iStock, File)

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For parents concerned about this mysterious illness affecting their child, the liver specialist offered some words of comfort, "Currently, there is no need to be overly worried. Although there clearly is a phenomenon ongoing, the case numbers are extremely low and severe hepatitis is still extremely rare." 

The physician said awareness is key. "Ensure children are up to date on their vaccinations. Continue the usual measures to prevent illness such as washing hands frequently, covering coughs and sneezes, avoiding touching eyes, nose, and mouth, and avoiding people who are known to be ill." DiNorcia said if your child has any concerning symptoms, contact a health care provider immediately.