The U.S. Naval Hospital Naples in Italy is pictured in an undated photo. Officials announced on Apr.20, 2026, that Legionella bacteria had been detected in the facility’s water system, though no cases of infection have been reported at the hospital. (Alison Bath/Stars and Stripes)
NAPLES, Italy — Water at the Navy’s largest installation in Italy recently tested positive for a potentially deadly bacterium, officials said.
Legionella was found in the water system at U.S. Naval Hospital Naples on April 20, according to a Facebook post Friday.
The bacteria can cause Legionnaires’ disease, a serious form of pneumonia that can be fatal. Symptoms appear two to 14 days after exposure and include a cough, fever and headaches. It also can cause Pontiac fever, a mild illness whose symptoms include muscle aches, headaches and fever.
There have been no reported or confirmed cases of infections caused by the bacteria, which is commonly found in water systems, the Facebook post said.
Legionella typically becomes a health concern only when it grows within building plumbing, the statement continued, adding that the illness generally isn’t contracted through drinking infected water or person-to-person contact.
It isn’t clear exactly where in the hospital’s water system the bacteria was found, how far it had spread or what caused the bacteria to infiltrate the facility’s water supply.
It also isn’t known what steps the hospital is taking to eradicate Legionella from its water or whether the problem has already been fixed. The hospital did not immediately respond to questions Monday.
“Risk management and remediation actions are already underway,” the statement said. Further updates will be given when more information is available, it added.
An outbreak of Legionnaires’ disease at an American Legion convention in Philadelphia in 1979 resulted in 29 deaths. The illness was unknown at the time and caused a panic as researchers scrambled to pin down the cause.
Current or past smokers, people ages 50 and older or those who have an underlying medical condition are among groups at increased risk for illness caused by Legionella, the hospital said.
