A Centers for Disease Control and Prevention report published Thursday revealed that pathogens including Legionella and nontuberculous mycobacteria are the top causes of waterborne disease outbreaks in the United States — and most originate from public water systems that reach nursing homes and assisted living communities.
Pathogens in the water are responsible for approximately 7.15 million illnesses, 118,000 hospitalizations and 6,630 deaths annually in the country. Exposure to Legionella and NTM in drinking water have been linked to 40% of hospitalizations and 50% of deaths, the report said.
A total of 214 outbreaks associated with drinking water were reported in the document and came from 28 states between 2015 and 2020. In total, there were at least 2,140 cases of illness from contaminated drinking water as well as 563 hospitalizations and 88 deaths. The team noted that the outbreaks are largely linked to wells and represented more than half of all cases.
The reporting system specified where outbreaks hit as well. Healthcare facilities such as nursing homes ad hospitals, as well as assisted living communities and rehabilitation facilities, were associated with 53% of outbreaks, 21% of cases, 66% of hospitalizations and 87% of deaths. Specifically, Legionella was the culprit in 52% of outbreaks, 21% of cases, 65% of hospitalizations and 85% of deaths.
Of the outbreaks, 87% were linked to pathogen biofilms, and 80% involved contaminated water from public water systems. Legionella thrives with the aquatic bacteria on the surface of biofilms, which give protection from water disinfection. Biofilms colonize drinking water distribution systems, where they form a habitat for Legionella growth in potable water — that can lead to human exposure.
Legionella was associated with 98% of biofilm-related outbreaks and was responsible for 92% of public water system outbreaks, 97% of hospitalizations and 98% of deaths. It also was tied to 98% of biofilm-related outbreaks in healthcare facilities, which resulted in 65% of hospitalizations and 85% of deaths reported during the study period.
Preventing the outbreaks through biofilm control and water management remains critical in health and nonhealth settings, authors of the report wrote.
