The Implications of Climate Change and Legionellosis for HVAC Professionals

Monday, December 1st, 2008 | Sick Building Syndrome

HVAC professionals should take note that Legionnaires’ disease is currently making headlines in various places around the U.S. and the rest of the world. The status of this disease on the world stage is always a subject of interest to people involved in HVAC, since a major part of HVAC design, installation, operation, and maintenance involves the prevention, detection, and treatment of Legionella, the bacterium that causes the disease. So people involved in the industry really ought to keep their eyes and ears open right now, as cases of legionellosis (which includes both Legionnaires’ disease and its milder form, Pontiac Fever) appear to be increasing sharply here in the U.S. and abroad, with profound implications.

The most visible case in the U.S. at the moment is a Legionnaires’ “cluster” that’s being reported in Newark, New Jersey. A widely circulated AP story (“Possible Legionnaires’ disease cluster in Newark”) reported on November 3 that health officials in New Jersey were “investigating a possible cluster of Legionnaires’ disease cases in Newark and Irvington,” with 15 cases occurring in October. Eight of them appeared to be definitely linked and one of them may have killed an elderly man, although it was still unclear whether he might have died of a preexisting illness. Newark’s Star-Ledger carried a story on the same event on November 4 (“Legionnaires’ disease ‘cluster’ kills one”), stating that the New Jersey Department of Health and Senior Services had alerted hospitals and physicians in the area, and was investigating possible sources for the outbreak, including “water cooling towers, hot tubs and public fountains.”

Other recent and current cases in the U.S. have been reported in New York, California, Illinois, and elsewhere.

The mere fact of these occurrences isn’t particularly noteworthy for a disease that, according to the U.S. Centers for Disease Control (CDC), causes the hospitalization of between 8,000 and 18,000 people in the U.S. every year. What demands attention is that they’re part of a growing trend.

Consider:

Government scientists at Britain’s Health Protection Agency have recently concluded that, in the words of a November 10 headline in the U.K. Independent, “Climate change could lead to a surge in Legionnaires’ disease.” The findings were presented at the HPA’s 2008 annual conference, where Agency scientists, after studying Britain’s record number of Legionnaires’ cases in 2006, reported discovering that “higher temperatures and increases in humidity are linked with an increase in cases” of Legionnaires, and that cases are clearly more numerous during heatwaves than in more stable weather. A scientist with the Agency’s Centre for Infections pointed out that this connection may have “important implications for public health authorities if climate change leads to warmer temperatures.”

And in the U.S., the journal Clinical Infectious Diseases published a major article in September (“Increasing Incidence of Legionellosis in the United States, 1990-2005: Changing Epidemiologic Trends”) that offered a clinical evaluation of the “abrupt increase in the incidence of legionellosis in the United States . . . since 2003.” An associated editorial in the same issue stated the upshot, as summarized by the Emerging Health Threats Forum: first, the trends “probably represent true changes in the incidence of the disease” in the U.S. Second, and in tacit agreement with Britain’s HPA, this could be linked to climate change. “At the time of writing,” says the editorial, “climate change due to anthropogenic greenhouse gas generation seems well under way in North America, and projected changes in temperatures and precipitation patterns might be expected to result in increases in the incidence of legionellosis, as well as other important infectious diseases with environmental reservoirs.”

For people involved in the heating, ventilating, and air-conditioning of the buildings where most of us spend a great deal of our time, the implications of this trend are profound and wide-ranging. If climate change really is occurring, then more and more people will likely be trying to spend more time indoors in heated and air-conditioned environments as weather patterns grow more severe. If the hot end of these weather gyrations really is contributing to an increase in legionellosis cases, then HVAC professionals will have to become ever more vigilant and skilled in their prevention, detection, and treatment of Legionella. This is no small task, and will probably require the coordinated efforts of both the government and the private sector.

NOTE: For a general introduction to the importance of Legionella and Legionnaires’ disease for this industry, see The Basics about Legionnaires’ Disease and HVAC Systems.

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Written by: Goodway Blogging Team

Tags: Centers for Disease Control, Health Protection Agency, HVAC Maintenance and Efficiency, HVAC professionals, legionnaires’ disease, Legionnares' cluster, Pontiac Fever, water cooling towers

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