(NBC News) — The Centers for Disease Control and Prevention is asking physicians nationwide to be on the lookout for unusual cases of severe hepatitis in children. The agency issued a health advisory on the matter Thursday.

Nine cases have been reported in Alabama, and an additional two have been identified in North Carolina, according to those states’ health departments.

Dozens of such cases have also been identified in the United Kingdom, Denmark, Spain and the Netherlands, the European Centre for Disease Prevention and Control announced Tuesday.

Hepatitis refers to inflammation of the liver, a condition that can result in diarrhea, abdominal pain, nausea and vomiting. Some of the children in Alabama developed jaundice, and blood tests showed signs of elevated liver enzymes.

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