From the May 2019 issue of HealthCare Business News magazine
What is driving the increase in Legionella cases?
The CDC estimates that there are about 25,000 yearly Legionella cases in the United States, although only 5,000 are reported because of the disease’s nonspecific symptoms. Cases are still growing at more than 25 percent per year, which is significant in relation to all other diseases. “Legionnaires’ disease is an emerging disease in the sense that the number of recorded cases of Legionnaires’ in the United States continues to increase,” according to Laura Cooley, M.D. from the Respiratory Diseases branch of the CDC. Cooley believes the increase is not only due to the aging population in the U.S., but that the warming of earth’s temperatures is creating the optimal conditions for bacterial growth.
An aging U.S. population is factual, and older adults are indeed more susceptible to Legionella. However, pointing to a warming climate would make sense if Legionella cases took place in warmer areas – the most recent cases occurred in Wisconsin during the winter and were allegedly caused by changes in the water system delivery inside the building. Other publication writers have pointed to the evolution of fixtures and equipment in building water delivery systems as a possible cause for the increase in reported cases. Some experts say that the public using hot tubs and swimming pools as toilets is increasing bacteria growth and making disease, such as Legionella more prevalent.
In reality, the growth driver is the advent of combining testing for Legionella in pneumonia cases. Since the initial symptoms are so similar, testing for both Legionella and pneumonia just makes sense. A Urinary Antigen Test is the most commonly used laboratory test for diagnosis of Legionnaires' disease. The test detects a molecule of the Legionella bacterium in urine. If the test is positive for Legionnaires’ disease, healthcare providers and facilities are to notify local health agencies. The purpose is to aid in identifying the source of transmission to prevent further exposure.
Sometimes knowing too much can be scary and testing for Legionella alongside pneumonia is likely the real driver of there being more stories of exposure in the media. Knowledge is important for understanding the proper maintenance requirements for building water systems and features to prevent public exposure.Back to HCB News