One child has died and 17 others have required liver transplants as global health experts race to determine the origin of at least 169 cases of acute liver inflammation in children spanning 11 countries.
The World Health Organization confirmed the hepatitis-related death Saturday but did not provide additional details about the child.
Hepatitis is the inflammation of the liver, typically caused by a virus, which can affect its ability to process nutrients and filter the blood, according to the U.S. Centers for Disease Control and Prevention.
“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,” the WHO wrote in a news release, adding, “While adenovirus is a possible hypothesis, investigations are ongoing for the causative agent.”
One week ago, only eight liver transplants had been linked to the clusters of pediatric liver inflammation.
According to the WHO, many patients reported gastrointestinal symptoms such as abdominal pain, diarrhea and vomiting “preceding presentation with severe acute hepatitis,” as well as jaundice and increased levels of the liver enzymes alanine aminotransaminase.
Meanwhile, most reported cases did not present with fever, and the viruses that most commonly cause acute viral hepatitis – such as hepatitis viruses A, B, C, D and E – have not been detected among any of the pediatric patients, the agency stated.
The United Kingdom has reported the lion’s share of the cases, or 114, followed by Spain with 13 cases, 12 in Israel, nine in the United States and a smaller number of cases confirmed in Denmark, Ireland, the Netherlands, Italy, Norway, France, Romania and Belgium, according to the WHO.
On Thursday, the CDC issued a health advisory, alerting health care providers and public health authorities of an investigation into cases of acute hepatitis of unknown origin.
>> Related: CDC alert: Mystery hepatitis causing liver damage in children
The nine U.S. cases confirmed by the WHO have been reported in Alabama, but officials with North Carolina’s Department of Health and Human Services have confirmed two additional cases in that state, NBC News reported.
According to CNN, the WHO said that the investigation into the root cause needs to focus on 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.”
Adenoviruses are typically associated with cold-like symptoms, fever, sore throat and pink eye but rarely cause severe hepatitis in healthy people, according to the CDC.
Public health officials have ruled out any link to COVID-19 vaccines, saying that none of the affected children had been vaccinated, the AP reported.