Adenoviruses are responsible for about 10 percent of fever-related infections among United States children, and most children will have at least one type of infection by age 10. Symptoms can range from a sore throat and fever to intestinal inflammation and neurological disease. Some patients develop neurologic diseases, which can lead to death for patients with compromised immune systems.
State officials were first notified of respiratory illnesses at the center on October 9, officials said.
A team from the health department were on hand at the center Tuesday to investigate.
But the health department said the patients affected are "medically fragile children".
"The team on Sunday found minor handwashing deficiencies and the Health Department is continuing to work closely with the facility on infection control issues", according to the statement.
The facility's pediatrics center cares for patients ranging in age from newborn to 22 years of age, according to its website.
Philly.com reported in August that the parents of the infant who died, Melanie Sanders, are suing the hospital for negligence.