More than 200 cases of a mysterious hepatitis illness that is striking previously healthy young children have been reported in 20 countries.
At least 228 probable cases of hepatitis of unknown origin, which was first recorded in the UK, have been reported to the World Health Organisation.
While the cause remains unknown, findings have suggested the rise in sudden cases may be linked to a common cold virus known as an adenovirus. Another theory is that child immunity levels have been lowered by Covid-19 restrictions such as social distancing.
Three children in Indonesia have died from the mysterious liver illness, the country's Health Ministry said.
That raised the global death toll to at least four.
The emergence of a possible new disease afflicting only young children – most cases are under the age of 10 with no underlying conditions – has been a growing concern for the global health community.
“As of May 1, at least 228 probable cases were reported to WHO from 20 countries, with over 50 additional cases under investigation,” WHO spokesman Tarik Jasarevic said.
Most of the cases are in Europe but there are others in the Americas, the Western Pacific and South-East Asia, he said.
The first cases were reported to the WHO on April 5, when the illness was found in 10 children in Scotland under the age of 10. More than 100 cases have now been recorded in Britain.
Some cases have caused liver failure and required transplants. Many cases reported jaundice and gastrointestinal symptoms, including abdominal pain, diarrhoea and vomiting.
The WHO refers to the outbreak of severe liver inflammations as acute hepatitis of unknown origin among young children.
“It is not yet clear if there has been an increase in hepatitis cases, or an increase in awareness of hepatitis cases that occur at the expected rate but go undetected,” the agency says on its website.
“While adenovirus is a possible hypothesis, investigations are ongoing for the causative agent.”
Adenoviruses are generally known to cause respiratory symptoms, conjunctivitis or even digestive disorders.
After the discovery of the first 169 cases, the WHO said common viruses that caused acute viral hepatitis (hepatitis viruses A, B, C, D and E) were not detected in any of them.