Re: legionaires disease -facts on etiology and name

[SAFarberMSPH@CS.COM]

Radsafe:

In regard to a number of posts [copied in part below] which contained only  partially correct info, see the following. Legionnaire's disease was given its name when two hundred and twenty-one Legionnaires at a convention in Philadelphia in 1976 contracted the disease and 34 people died. The source of the outbreak was definitely traced to aerosolized contaminated mist from a small cooling tower which was part of the air conditioning system at the hotel as noted in red in the excerpt below  from Creighton School of Medicine.

It is estimated that about 25,000 people a year in the US contract the respiratory infection caused by the legionnaire's disease bacterium.

Stewart Farber, MS Public Health
Public Health Sciences
email: SAFarberMSPH@cs.com
====

Legionnaire’s Disease

Historical Background & Importance

Legionnaire’s Disease is an acute respiratory infection caused by the bacteria Legionella pneumophila. The bacterium causes a serious pneumonia. Legionella got its name from the Legionnaires who contracted the disease during the first known outbreak in Philadelphia in 1976. Two hundred and twenty-one Legionnaires contracted the disease and 34 people died. The disease was traced to the air conditioning system at the American Legion where they were meeting. Legionella can be found in many types of water systems other than air conditioning systems, but the infection cannot be acquired from another person.
There have been a few major outbreaks since the original one in 1976. The second largest outbreak occurred in England in 1985 when 101 people contracted the disease and 28 people died. In 1993 four people contracted the disease in Saudi Arabia and 2 people died. Australia has had three major outbreaks, two of them due to air conditioning systems and one due to a shower storage tank. Health authorities in Australia now recommend routine cleaning of air conditioning systems, especially after an extended shut-down.

Incidence and Cause

L. pneumophila is an aerobic, gram negative bacterium which is often missed on routine culture. Special culture media, which includes a compound known as L-cysteine, is needed to grow L. pneumophila in the laboratory for purposes of diagnosis.
Traces of L. pneumophila can be found in many aquatic habitats such as lakes and rivers. It can also be found in man-made reservoirs like cooling towers and wells. Warm, sedentary water favors proliferation and growth of L. pneumophila. Most cases of Legionnaire’s Disease result from exposure to infected water supplies and thus occur in epidemics when many people are exposed to the same infected water.
L. pneumophila is usually spread by inhalation of aerosolized droplets of infected water. In the famous 1976 outbreak, a cooling tower was the source of the infected water. Patients can also contract the bacteria from drinking infected water, the route most commonly seen in hospitals. In fact, L. pneumophila is one of the most common causes of pneumonia in hospitals with infected water supplies. It is also the third most common cause of community-acquired pneumonia behind H. influenzae and S. pneumoniae. The most commonly affected are those who are immunocompromised, or those who have damaged respiratory cilia (i.e. smokers). Patients with hairy cell leukemia are also more susceptible.

from:
http://medicine.creighton.edu/forpatients/Legion/Legion.html

----- Original Message -----
From: "Norman Cohen" <ncohen12@HOME.COM>
To: <radsafe@list.vanderbilt.edu>
Sent: Monday, November 19, 2001 8:04 AM

In fact I was sure that the disease started in Philly at the Ben Franklin
Hotel at a legionairres convention. Thats why I was surprised to see a
reference to cooling towers causing the disease.
>
> "Flanigan, Floyd" wrote:
>
> > As to the legionaire's issue:The desease got it's name from an American
Legion Post down wind from a cooling tower which bred the bacteria which
causes the desease.