Public awareness. On November 21, CNN & TIME, a TV newsmagazine, aired a segment on Legionnaires’ disease in hospitals. CNN reported that “every year thousands of patients contract [Legionnaires’] disease from contaminated hospital water systems.” The show included an interview with Dr. Victor Yu, a Legionnaires’ expert from the VA Medical Center in Pittsburgh: “These outbreaks, they’re actually occurring all through the country every week,” said Yu. “It’s an explosive problem to realize that people are dying, to realize that the means are there for preventing all this from happening, and that those means are not being exercised.” Indeed, awareness of Legionnaires’ disease is growing, and more people are realizing that preventive measures are not implemented in most buildings.

Outbreaks. Most cases of Legionnaires’ disease still go undetected, and the public hears about very few cases that are detected. However, some of the multicase outbreaks make the news. For example, an outbreak in the Netherlands, which occurred in late February-early March 1999, involved 242 cases of illness and 28 deaths. The outbreak was blamed on a whirlpool spa displayed at a trade show. Briefs on recent outbreaks are posted at

Patient testing. Special laboratory tests are required to detect Legionnaires’ disease. Most hospitals still do not make these tests available. But a new 15-min test (by Binax Inc., for a common strain of Legionella makes patient testing easier and cheaper, which should result in more testing and more diagnosed cases.

Lawsuits. Legionnaires’ disease is conducive to lawsuits. A case of Legionnaires’ disease can be linked to an environmental source (e.g., a cooling tower) by comparing the Legionella strain found in the victim to the strain found in a water sample. This may allow a plaintiff to rule out some water supplies (in the victim’s house) and implicate others (in the defendant’s building) as the source of the Legionellae that caused the illness — similar to the way DNA tests are used to link criminal defendants to a murder scene. Legionnaires’ lawsuits are not rare. Several are in process at the time of this writing.

Water sampling. The debate continues about whether or not to test water routinely for Legionella. Guidelines by the [U.S.] Centers for Disease Control and Prevention (CDC, Atlanta) do not include a recommendation for routine sampling unless cases of disease have been identified, but CDC officials have suggested recently that routine testing may be appropriate in hospitals that treat high-risk patients. Some building owners voluntarily test plumbing systems and cooling towers for Legionella in order to check preventive measures and establish a defense against lawsuits.

New technology. In plumbing systems, copper-silver ionization has outperformed chlorine, partly because of its apparent ability to disinfect systems laden with biofilm. Studies indicate chlorine dioxide is also more effective than chlorine, plus lower in cost and less harmful to ingest. Suppliers claim it even removes biofilm over time. Chlorine dioxide has been used for drinking water in the United Kingdom, but it is still uncommon in the United States, partly because of concerns about the safety of onsite generation of chlorine dioxide. However, new technology (by Halox, claims to make the generation process much safer than before.

Chlorine dioxide may be effective against Legionella in cooling towers also. Look for reports of studies on actual cooling towers (rather than laboratory models). Another biocide, by Sterilex (, was recently accepted by the U.S. EPA and also claims to remove biofilm from cooling tower piping. The Sterilex product is added to cooling towers periodically as a supplemental biocide. Information. A free Legionella newsletter, sent by e-mail about once a month, covers new technology for Legionella control, outbreaks briefs, and new findings on Legionnaires’ disease. To register for “Legionella E-news”, go to (the web site of HC Information Resources). Also, Denis Green of Australia has formed a Legionella discussion group. To join, go to

Regulations. The New York State Department of Health was to send a letter of Legionnaires’ recommendations to 250 hospitals and 650 nursing homes in December. A NYDOH official said it is deviating from CDC’s no-routine-sampling guidance by recommending routine sampling in hospitals that treat high-risk patients (e.g., hospitals that perform transplants). The State of Maryland is also beginning the process of drafting Legionnaires’ guidance.