Hepatitis outbreak: Where has the mystery strain that has killed at least one child been detected?

At least one child has died after falling ill from a mysterious outbreak of acute hepatitis that has infected children in 10 European countries, the World Health Organization (WHO) has confirmed.

As of April 21, there had been at least 169 cases of "unknown origin" around the world, the WHO said on Saturday.

"Cases are aged 1 month to 16 years old. 17 children (approximately 10 per cent) have required liver transplantation; at least one death has been reported," the WHO said on Saturday.

Hepatitis is inflammation of the liver, which is a vital organ for processing nutrients, filtering blood, and fighting infections.

While the WHO said that the cause of the infections was still being investigated, the UN body noted that an adenovirus infection leading to acute hepatitis was one possible option under consideration.

"The common viruses that cause acute viral hepatitis (hepatitis viruses A, B, C, D, and E) have not been detected in any of these cases," the WHO said in a statement, adding that adenovirus had been detected "in at least 74 cases".

As of April 21, 114 cases had been reported in the United Kingdom, 13 in Spain, 12 in Israel, nine in the United States, six in Denmark, fewer than five in Ireland, 4 each in the Netherlands and Italy, 2 in Norway and France and 1 each in Romania and Belgium, the WHO said.

The WHO did not reveal where or when the death had taken place.

Adenoviruses can cause a range of different illnesses, ranging from mild to more severe.

According to the US Centers for Disease Control and Prevention (CDC), people infected with an adenovirus can display cold or flu-like symptoms, fever or sore throat, as well as more severe illness like acute respiratory infections like bronchitis or pneumonia.

They can also