While mild forms of hepatitis are common, the severity of the reported cases worries health authorities.
Health officials from several countries in Europe and the United States are investigating cases of a serious liver disease in children that was first identified in the UK.
The European Center for Disease Prevention and Control said on Tuesday it had detected an unknown number of cases of hepatitis, or inflammation of the liver, in Denmark, Ireland, the Netherlands and Spain.
The UK said last week it had identified 74 severe cases since January and the US said nine cases of acute hepatitis had been discovered in the state of Alabama.
“Given the increase in cases reported over the past month and improved case-finding activities, more cases are likely to be reported in the coming days,” officials from the Organization said. World Health Organization in a statement last week.
While mild forms of hepatitis are relatively common in children, the severity of reported cases has given health authorities pause.
“Mild hepatitis is very common in children following a series of viral infections, but what you’re seeing right now is quite different,” said Graham Cooke, professor of infectious diseases at the Imperial College London, to the Associated Press news agency.
Some of the UK cases required specialist care in liver units and a few required liver transplants. The nine children found with the disease in the United States were between the ages of 1 and 6. Two liver transplants needed.
Scientists in the UK have previously said one of the possible causes they are investigating is adenoviruses, a family of common viruses typically responsible for conditions such as pink eye, sore throat or diarrhoea.
Investigators were also looking at any link between the disease and COVID-19, although some noted the disease would likely be more widespread given the prominence of the coronavirus.
Meanwhile, British public health officials have ruled out any link to COVID-19 vaccines, saying none of the children involved had been vaccinated.
The World Health Organization said no other links had been found between the affected children in the UK and none had recently traveled overseas.
Laboratory tests are underway to determine if a chemical or toxin may be causing the disease.