CHICAGO (NewsNation) — The Centers for Disease Control and Prevention is investigating nearly 200 pediatric patients with hepatitis of unknown cause. The cases, which have included deaths, have been reported in more than 30 states and territories over the past seven months.

Hepatitis is defined as swelling of the liver.

During the CDC’s last update on May 5, they reported investigating 109 cases; however, the agency said that most of the latest cases are “retrospective” cases — including reported cases that date back to October 2021, and many of them are just now being reported.

Doctors nationwide have reported treating children with hepatitis who have symptoms ranging from those resembling the common cold to much more severe signs including swelling of the liver and/or yellowing of the skin and eyes.

At least 36 states and territories have reported illness, and five children have died. The CDC said no additional deaths have been reported since February.

Officials said that the majority of the children who experience hepatitis have fully recovered from their symptoms — but the question of why they were sick remain.

The CDC said it’s examining possible causes of the cases, including ruling out the common viruses associated with hepatitis A, B, C, D, and E. Now, health officials are looking into a possible connection between the illness and COVID-19. However, so far, no evidence has linked the two.

The CDC stated adenovirus, a common virus that often causes mild cold or flu-like symptoms, has been identified in almost half of the pediatric patients with hepatitis.

The agency warns parents and caregivers to be aware of symptoms, including jaundice. They should immediately contact health care providers if symptoms appear or if they have any concerns.