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Reported cases of mystery hepatitis in kids doubled since last week: What to know

The cases continue to rise around the globe.
/ Source: TODAY

The number of acute pediatric hepatitis cases with an unknown cause continues to rise across the globe.

The number of worldwide cases now stands at 450, according to a May 11 report from the European Centre for Disease Prevention and Control — nearly double the 228 cases the World Health Organization reported last week.

The ECDC, a European Union agency, stated in its update Wednesday that roughly 105 cases have been identified in 13 European Union countries as of May 10. Italy has the most cases of EU countries, with 35, followed by Spain's 22.

The U.S. Centers for Disease Control and Prevention reported last week that it was investigating 109 cases in 24 states and Puerto Rico, as well as five deaths connected to the outbreak. Most of the children were hospitalized, and eight needed a liver transplant.

RELATED: Mystery hepatitis outbreak in kids: Which states are investigating cases?

The United Kingdom has also identified roughly 163 kids with acute hepatitis of unknown cause. At least 20 countries have reported cases of last week, according to WHo.

The ECDC said in its update that the cause of these hepatitis cases is "still under investigation. A possible association with current adenovirus infection has been found in cases in the UK in particular but other hypotheses and possible co-factors are under investigation. Most cases continue to be reported as sporadic un-linked cases."

Hepatitis, which is an inflammation of the liver, is typically caused by one of the hepatitis viruses — hepatitis A, B, C, D or E. In these newer cases, though, the typical causes of hepatitis have been ruled out. The ECDC report didn't specify the percentage of global cases in which the child tested positive for an adenovirus, but adenovirus has been detected in about half the cases in the U.S. and U.K.

The first reported U.S. cases in the outbreak were in Alabama in October, and all of the children, between 1 and 6 years old, tested positive for adenovirus. Adenoviruses are common and usually result in cold-like and gastrointestinal symptoms. Prior to these cases, adenoviruses were not known to cause hepatitis in healthy children, according to the CDC.

Last week, the CDC said it is working with state health departments and "investigators are examining a possible relationship to adenovirus type 41 infection."

"It is not yet clear whether there has been an increase in the number of cases of hepatitis in children, or improvements in detecting cases. It is not unusual for the cause of some hepatitis cases in children to remain unknown," the CDC added.

The CDC also issued guidance for parents to protect their children.

  • Know the symptoms of liver inflammation, which include: Be aware of the symptoms of liver inflammation, which include: fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, light-colored stools, joint pain, jaundice (yellowing of the skin).
  • Make sure your kids are up to date on their vaccinations.
  • Encourage kids to take steps to prevent illness, like washing hands, avoiding sick people, covering coughs and sneezes, and avoiding touching their nose, hands and mouth.

If you have any questions about your child's health, contact your health provider.