hepatitis

US health officials say infection with adenovirus, a common childhood virus, is the leading hypothesis for the cases.

At least 600 children in at least 34 countries have developed cases of sudden severe liver inflammation, with a large number of cases in the US and UK.

Cases have been reported in 20 countries, with 70 additional cases from a further 13 countries which are pending classification as tests await completion.

Authorities have not determined a definitive cause.

It is part of an unexplained global phenomenon involving hundreds of cases, with Indonesia this week also reporting three deaths.

Adenovirus 41 is known to cause gastroenteritis in children, but 'it is not usually known as a cause of hepatitis in otherwise healthy children', the CDC says.

The outbreak was first reported this month in Britain – which has registered 111 cases, mostly in children under 10 – and has since been identified in at least 12 countries worldwide.

At least 169 cases have been reported in children in 12 countries, with 114 in the UK alone.

The US Centers for Disease Control and Prevention says it is working with counterparts in Europe to understand the cause of the infections.

Cases have now been recorded in children in the US, Denmark, Ireland, the Netherlands and Spain.

Some of the cases were so severe that patients had to be transferred to specialist children's liver units, while six children had liver transplants.