According to the WHO, these cases of hepatitis of unexplained origin have been identified in 20 countries. A total of 70 other suspected cases, identified in 13 countries, are waiting to be confirmed by tests.

The World Health Organization (WHO) announced on Tuesday that it had identified 348 probable cases of hepatitis of unknown origin, and favored the hypothesis of an adenovirus to explain this mysterious disease which mainly affects children. Only six countries have more than five cases, but the UK alone has reported 160 patients.

“Significant progress has been made with respect to further investigations and the refinement of working hypotheses,” Philippa Easterbrook, of WHO’s Global Hepatitis Program, told a news conference.

An adenovirus responsible?

In the United States, health authorities said on Friday they were investigating 109 cases, including five fatalities. Three children also died in Indonesia.

“At this time, the main hypotheses remain those involving the adenovirus, also taking into important consideration the role of Covid, either as a co-infection or as a prior infection,” said Philippa Easterbrook.

Tests carried out last week confirmed that around 70% of cases were positive for adenovirus, with subtype 41, normally associated with gastroenteritis, being the most common, she added.

Adenoviruses are usually spread through personal contact, respiratory droplets and surfaces. They are known to cause respiratory symptoms, conjunctivitis or digestive disorders. The tests also showed that around 18% of the patients were positive for Covid-19.

“Next week we will focus on serological testing for previous Covid exposures and infections,” Philippa Easterbrook said.

After the discovery of the first 169 cases, the WHO indicated that the hepatitis A, B, C, D and E viruses had not been detected in any of the patients.

Most patients presented with gastrointestinal symptoms, including abdominal pain, diarrhea and vomiting, or jaundice. Some cases have caused liver failure and required transplantation