- Oops!Something went wrong.Please try again later.
According to the international health agency, the cases — all aged 1 month to 16 years old — have resulted in one death and 17 liver transplants.
WHO also reported that many cases reported gastrointestinal symptoms including abdominal pain, diarrhea and vomiting preceding presentation with severe acute hepatitis, increased levels of liver enzymes and jaundice. However, most cases did not have fevers.
The majority of cases were in the United Kingdom (114), followed by Spain (13), Israel (12), the United States (9) and Denmark (9). The Netherlands, Ireland, Italy, Norway, France, Belgium, and Romania also reported less than 5 cases each.
"It is not yet clear if there has been an increase in hepatitis cases, or an increase in awareness of hepatitis cases that occur at the expected rate but go undetected," WHO said in the release. "While adenovirus is a possible hypothesis, investigations are ongoing for the causative agent."
RELATED VIDEO: Wash. Nurse Allegedly Used Her Own Drug Needles on Patients, Leading to Hepatitis C Infections
Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.
Investigation of the multi-country outbreak is ongoing and each country has implemented its own testing and surveillance with the support of WHO.
"Factors such as increased susceptibility amongst young children following a lower level of circulation of adenovirus during the COVID-19 pandemic, the potential emergence of a novel adenovirus, as well as SARS-CoV-2 co-infection, need to be further investigated," WHO added.
Health officials say there is no need to restrict travel for any country with reported cases. Regular hand washing and hygiene are suggested as comment prevention measures.
Last week, the U.S. Centers for Disease Control issued a nationwide alert warning of the rise in severe hepatitis cases in young children.
The CDC said they were issuing the health alert "to notify US clinicians who may encounter pediatric patients with hepatitis of unknown etiology to consider adenovirus testing and to elicit reporting of such cases to state public health authorities and to CDC."