A severe hepatitis disease of unknown origin found in 12 countries has led to the death of at least one child, said the World Health Organisation (WHO).
At least 169 cases of the acute viral hepatitis disease have been reported in children aged from a month to 16 years old in countries including the UK, the US, Spain, Italy, and France, the UN health agency said on Saturday.
At least one death was reported from the “acute, severe” hepatitis strain that has led to 17 children (approximately 10 per cent) requiring liver transplantation, the agency pointed out.
It is as yet unclear if there has been an increase in hepatitis cases, or a rise in awareness of hepatitis cases that occur at the expected rate but go undetected, according to the WHO.
The causative agent behind the reported cases also remains unknown.
Symptoms from the disease include markedly elevated liver enzymes along with reports of many suffering gastrointestinal symptoms including abdominal pain, diarrhoea and vomiting, preceding presentation with severe acute hepatiti and jaundice, the WHO said.
Fever was not reported in most of the cases, the UN body said.
Reports suggest patients have levels of liver enzymes aspartate transaminase (AST) or alanine aminotransaminase (ALT) greater than 500 international units per litre (IU/L).
For comparison, normal levels of AST and ALT in children fall in the range of 10-40 (IU/L).
Common viruses that cause acute viral hepatitis, including hepatitis viruses A, B, C, D and E, have not been detected in any of these cases, but adenovirus has been detected in at least 74 cases.
Eighteen of the cases have been identified as F type 41.
About 20 cases were detected with a co-infection of Covid and adenovirus, the WHO noted.
While adenovirus is one of the suspected causes of the reported cases, WHO said it “does not fully explain the severity of the clinical picture”.
“Infection with adenovirus type 41, the implicated adenovirus type, has not previously been linked to such a clinical presentation,” it added.
While past cases of hepatitis in immunocompromised children with adenovirus infection were reported, the WHO said the particular adenovirus type 41 is not known to be a cause of hepatitis in otherwise healthy children.
Experts also pointed out that the increased reported prevalence of adenovirus may be due to enhanced laboratory testing for the virus.
With further work needed to identify additional cases across the globe, the UN body said the current priority is to determine the cause of these cases to further refine control and prevention actions.
“Other infectious and non-infectious explanations need to be excluded to fully assess and manage the risk,” the WHO noted.
It encouraged member states to follow prevention measures for adenovirus and other common infections, including regular hand washing and respiratory hygiene, as well as to identify, investigate and report potential cases fitting the case definition.
“Epidemiological and risk factor information should be collected and submitted by the Member States to WHO and partner agencies through agreed reporting mechanisms. Any epidemiological links between or among the cases might provide clues for tracking the source of illness,” the WHO said.
It recommended the testing of blood, serum, urine, stool, and respiratory samples, as well as liver biopsy samples in suspected patients with further virus characterisation including genome sequencing.
The UN body said it does not recommend any restriction on travel and/or trade with the UK or any other country where cases are identified, based on the currently available information.