Transmission by aspiration?

I was directed to your site through the bibliography in Protect Yourself from Legionnaires’ Disease, by Matt Freije. Your conclusions regarding transmission of the disease differ significantly from the book and other sites I have investigated, including material at the CDC. Given the interesting hypothesis, your site states that the most common mean of transmission is through aspiration. Could you please explain how this could account for the large outbreaks that have occurred, such as in Pittsburgh and other cities throughout the world?


My wife contracted what was diagnosed as Legionnaires’ in New York. While the blood and urine tests were both negative (she was not able to produce sputum to culture), the infectious disease specialist diagnosed the disease based on x-rays of the chest and other symptoms. We have an apartment in New York that we use as a second home. When I contacted the New York Department of Health, they recommended having every faucet, showerhead, and air conditioner in the apartment tested. Do you advise that we follow through with this? We received an estimate of $1800, but I am highly skeptical that this would be worthwhile. I am understanding through other FAQs on your website that there is no probability of someone contracting the disease from showers or faucets, as well as air conditioners.


Finally, a friend of mine read some research that Legionnaires’ disease cannot be reconstructed by a person that has already had it. I haven’t found any other information that confirms this. Do you have an opinion?


Thank you very much.


The issue of aspiration versus aerosolisation and drinking water versus cooling towers/air conditioners is a controversial one that can best be answered by using evidence based medicine and scientific data. If you have a scientific background, you can read these following two articles and judge for yourself.

1) Cooling towers and Legionellosis: A condundrum with proposed solutions.

2) Mode of transmission of Legionella pneumophila: A critical review.

One circumstantial piece of evidence is that our scientific group remains premier in Legionnaires’ disease. Individual advocates of aerosolisation and cooling towers have disappeared – it is difficult to make a longterm contribution if you are in error.

Large outbreaks have not occured in Pittsburgh – that is where we are! (There was a recent outbreak at the Pittsburgh VA, but that was due to neglect and poor maintenance practices – not misinformation). Pittsburgh, PA has more documented cases of Legionnaires’ disease than most US states due to active surveillance!

The reason cooling towers have been identified is due to one simple fact. It is obilgatory for any outbreak to culture any putative sites. The cooling tower outbreaks never culture the drinking water! If that is done, the drinking water is always found to be the source. So, should you spend $1,800? No, save your money. (If you want to spend it, our Special Pathogens Laboratory can culture your water. We usually will perform these cultures gratis for home residents, but we require that blood and urine tests document the presence of Legionnaires’ disease.) If you wife is taking steroids or immunosupressive medicines, she should avoid drinking tap water. Note that in the US, transplant recipients are advised not to drink tap water. Instructions are giving on on boiling tap water, and then cooling it for drinking.

Your friend is correct. Although we have seen more cases of Legionnaires’ disease than anyone in the world, we have only seen one patient who has experienced a recurrent case of Legionnaires’ disease. So it appears that some immunity to Legionella may occur. This infor is not in the medical literature, it is on our website.