​​ ​​​​APHL supports Legionella testing in public health laboratories by providing hands-on training, developing testing resources, evaluating new testing technologies and building testing capability and capacity.

Legionella bacteria naturally occur in fresh water but can multiply to harmful levels in man-made water systems that are not properly maintained. Infection with Legionella bacteria (Legionellosis) varies in severity from a mild illness (Pontiac fever) to severe pneumonia (Legionnaires' disease). The most common route of exposure is inhalation of aerosolized water contaminated with Legionella  bacteria. Legionella pneumophila serogroup 1 is the predominant species and serogroup associated with Legionnaires' disease.

Public health laboratories may perform clinical and/or environmental testing for Legionellosis case detection, outbreak response and surveillance. Laboratory testing for investigation of suspected Legionellosis outbreaks can be complex, as Legionella bacteria are notoriously difficult to culture and linking human cases to environmental sources is very challenging.​​

Legionella Reference Center

In 2023, APHL and CDC launched the Legionella Reference Center (LRC). Through a competitive process, the State Hygienic Laboratory at the University of Iowa was selected as the LRC. The reference center performs Legion​​ella testing for clinical and environmental case and outbreak samples submitted by governmental public health and environmental laboratories.​

All US state, local and territorial public health and environmental laboratories are eligible for enrollment in the LRC. Eligible laboratories must submit an enrollment application and receive approval prior to using the reference center. In order to access the enrollment application, you will need to log into your APHL account (Create a free APHL account​ if you don't already have one)​. CDC testing services remain available ​​​as described on the CDC testing directory​​.

Enroll in the Legionella Reference Center

Legionella Reference Center Resources