Health officials worldwide have been on high alert since early April as healthy, young children suddenly started developing cases of acute hepatitis with no known cause.

Seven probable cases of severe acute hepatitis were reported over a six-month period at a Toronto hospital on Monday, with one pediatric case reported in Manitoba on Tuesday.

Officials are now recommending that parents should look for symptoms that include fatigue, nausea and vomiting. CTV News spoke to medical experts for their recommendations to parents.

WHAT ARE THE SYMPTOMS?

According to the World Health Organization (WHO), many cases globally have reported gastrointestinal symptoms including stomach pains, diarrhea and vomiting. It is noted that fever wasn’t reported as a symptom.

Many hepatitis symptoms can be mistaken for stomach flu, but parents should be on the lookout for “yellow discolouration of the skin and yellow discoloration of the white of the eyes,” both of which are signs of jaundice, Dr. Dina Kulik, a Toronto-based pediatrician told CTV’s News Channel on Tuesday

Jaundice is an indication that something is wrong with the liver, and medical advice should be sought immediately.

The PHAC recommends that parents should watch for symptoms that also include dark urine, loss of appetite, and light-coloured stools.

The majority of children have spontaneously recovered, Dr. Deirdre Kelly, professor of pediatric hepatology at the University of Birmingham, told CTV News on Tuesday

“While this is a serious disease if their child develops it, the chances are they will recover on their own,” she said.

WHAT ARE THE POTENTIAL CAUSES?

While hepatitis A, B, or C viruses are typically associated with acute hepatitis, the recent cases of acute hepatitis in children are unusual insofar as doctors have not determined their cause.

Current investigations suggest a link to an adenovirus, according to the WHO and ECDC.

Adenoviruses are very common and can spread from person to person, causing a range of illnesses including colds, pinkeye and gastroenteritis.

Close to half of the hepatitis cases, including those in the U.S., have been tied to an adenovirus, with lab tests indicating some children were infected with type 41 associated with gastroenteritis, causing diarrhea and vomiting. At least 19 cases also involved a COVID-19 co-infection.

The WHO has ruled out hypotheses related to side effects from the COVID-19 vaccines as the vast majority of affected children did not receive COVID-19 vaccination, they said.

ARE THERE ANY PREVENTATIVE MEASURES?

Kulic says that cautionary measures to prevent cases are hard to prescribe because the cause is unknown. It also remains uncertain why some cases around the world have led to liver transplants and why, in other cases, children recovered quickly.

The WHO says that common prevention measures for adenovirus and other common infections involve regular hand-washing and respiratory hygiene.

Parents concerned about inconsistent symptoms should take their children in for a blood test immediately, the WHO says.