The Centers for Disease Control (CDC)’s Morbidity and Mortality Weekly Report (MMWR) report for September (Weeks 36 through 39, August 31 through September 27) lists 285 cases of diagnosed Legionellosis being reported across the United States and New York City via the CDC’s National Notifiable Diseases Surveillance System (NNDSS).

Legionnaires Pneumonia

Ohio leads the country with the most reported cases (54), followed by New York City (48), New York State (41), Florida (27), Pennsylvania (16), and Texas (13). These dates of diagnosis are not included in the MMWR report.

Additional small clusters and single cases occurred in Alabama (2), Arizona (4), Arkansas (1), California (1), Illinois (1), Indiana (1), Kentucky (3), Louisiana (1), Massachusetts (8), Maine (4), Maryland (9), Michigan (6), Minnesota (4), Nebraska (1), North Carolina (9), Oklahoma (3), Oregon (4), Rhode Island (6), South Carolina (3), Tennessee (6), Virginia (7), and Washington State (2).

It’s been a bad year for Legionellosis cases in Ohio. The state’s largest outbreak ever occurred in July at Wesley Ridge Retirement Community in Reynoldsburg, Ohio, killing 6 residents and sickening 39 other residents, visitors, and an employee between the ages of 63 and 99. The Legionella bacteria was eventually detected in both a facility cooling tower and in a building’s drinking water system.

During the same time period, 1 man died and another became ill with Legionnaires’ Disease at St. Mary’s, Ohio. Both men were employees of AAP, an auto parts supplier. Investigators are still seeking the source of the Legionella bacteria.

In a separate case, Toledo-Lucas County and Ohio state health department officials identified Legionnaire’s Disease as the causative agent of a pneumonia outbreak at a Lucas County Jobs and Family Services building that hospitalized 11 employees (out of 15 sickened) in early July. The bacteria, a rare subgroup of Legionella bacteria believed to be the first confirmed case of the strain in the U.S., was found in the facility’s cooling system.

The CDC estimates that, in the U.S., between 8,000 and 18,000 people are hospitalized with Legionnaires’ Disease each year; only around 3,000 cases of the potentially fatal disease, however, are reported annually to the CDC.