One Hundred Cases, Ten Fatalities in New York Legionnaires' Outbreak

Published August 5, 2015

Updated August 7, 2015

Public health authorities are investigating an outbreak of Legionnaires’ disease in the South Bronx section of New York City that has claimed ten lives since July 10. According to The New York Times, five cooling towers within a 20-square-block area have tested positive for Legionella. As of Aug. 7, the total number of Legionnaires’ cases in the outbreak has risen to 100, including the ten fatalities.

Among the buildings whose cooling towers tested positive for Legionella are a hotel, an office building, and a mall, the Times reported.

In a July 29 press release, the New York City Department of Health and Mental Hygiene advised city residents experiencing flu-like symptoms to seek immediate medical attention.

In recent years, incidence of Legionnaires’ disease has increased significantly both in New York City and nationwide. According to a study (PDF) published in the November 2014 issue of Emerging Infectious Diseases, between 2002 and 2009 the number of Legionnaires’ cases in the city rose 230 percent.

For the U.S. as a whole, the increase is even more startling. According to the CDC’s Morbidity and Mortality Weekly Report, the incidence of Legionnaires’ in the general population rose 320 percent, from 0.42 per 100,000 in 2001 to 1.36 per 100,000 in 2011.

A recent publication, Recognition, Evaluation, and Control of Legionella in Building Water Systems, available from the AIHA store, offers guidance for industrial hygienists and other OEHS professionals on assessing building water systems before disease occurs. The publication’s editors discussed the new guidance in an article published in the June/July issue of The Synergist.

“It appears that public health officials see only the tip of the iceberg and investigate only those cases determined to be part of an outbreak,” the article states. “Historical data suggest that the number of reported cases of [Legionnaires’ disease] could represent less than 8 percent of actual cases.”

More information on Legionnaires’ disease is available from the CDC website.