One-Third of Waterborne Infections Linked to Hotel Pools, Hot Tubs –CDC
Crypto parasite continues to cause most outbreaks and illnesses linked to pools and water playgrounds.
New data from the Centers for Disease Control (CDC) shows one-third of recreational waterborne infections are acquired in hotel pools or hot tubs.
The parasite, Cryptosporidium [“Crypto”] bacteria, which causes the majority of outbreaks and illnesses, is spread by swallowing water contaminated with feces.
Morbidity and Mortality Weekly Report (MMWR) – Outbreaks Associated with Treated Recreational Water — United States, 2000–2014
Outbreaks associated with exposure to treated recreational water can be caused by pathogens or chemicals in venues such as pools, hot tubs/spas, and interactive water play venues (i.e., water playgrounds). During 2000–2014, public health officials from 46 states and Puerto Rico reported 493 outbreaks associated with treated recreational water. These outbreaks resulted in at least 27,219 cases and eight deaths. Among the 363 outbreaks with a confirmed infectious etiology, 212 (58%) were caused by Cryptosporidium (which causes predominantly gastrointestinal illness), 57 (16%) by Legionella (which causes Legionnaires’ disease, a severe pneumonia, and Pontiac fever, a milder illness with flu-like symptoms), and 47 (13%) by Pseudomonas (which causes folliculitis [“hot tub rash”] and otitis externa [“swimmers’ ear”]). Investigations of the 363 outbreaks identified 24,453 cases; 21,766 (89%) were caused by Cryptosporidium, 920 (4%) by Pseudomonas, and 624 (3%) by Legionella. At least six of the eight reported deaths occurred in persons affected by outbreaks caused by Legionella. Hotels were the leading setting, associated with 157 (32%) of the 493 outbreaks. Overall, the outbreaks had a bimodal temporal distribution: 275 (56%) outbreaks started during June–August and 46 (9%) in March. Assessment of trends in the annual counts of outbreaks caused by Cryptosporidium, Legionella, or Pseudomonas indicate mixed progress in preventing transmission. Pathogens able to evade chlorine inactivation have become leading outbreak etiologies. The consequent outbreak and case counts and mortality underscore the utility of CDC’s Model Aquatic Health Code (https://www.cdc.gov/mahc) to prevent outbreaks associated with treated recreational water.
46 outbreaks infect more than 27,000 people
During 2000–2014, public health officials from 46 states and Puerto Rico reported 493 outbreaks associated with treated recreational water, which resulted in at least 27,219 cases and eight deaths. Etiology was confirmed for 385 (78%) outbreaks. Among these, 363 (94%) were caused by pathogens (including four caused by both Cryptosporidium and Giardia) and resulted in at least 24,453 cases. Twenty-two (6%) outbreaks were caused by chemicals and resulted in at least 1,028 cases. Among the 363 outbreaks with a confirmed infectious etiology, 212 (58%) were caused by Cryptosporidium, 57 (16%) by Legionella, and 47 (13%) by Pseudomonas. Of the 24,453 cases, 21,766 (89%) were caused by Cryptosporidium, 920 (4%) by Pseudomonas, and 624 (3%) by Legionella. Of the 212 outbreaks caused by Cryptosporidium, 24 (11%) each affected >100 persons; four of these outbreaks each affected ≥2,000 persons. At least six of the eight deaths,¶ which all occurred after 2004, were in persons affected by outbreaks caused by Legionella.
32% of infections acquired in hotels
Hotels** (i.e., hotels, motels, lodges, or inns) were the leading setting associated with 157 (32%) of the 493 outbreaks. Of the 157 hotel-related outbreaks, 94 (60%)†† had a confirmed infectious etiology, 40 (43%) were caused by Pseudomonas, 29 (31%) by Legionella, and 17 (18%) by Cryptosporidium.§§ Sixty-five (41%) hotel-related outbreaks were associated with hot tubs/spas, and 47 (30%) started during February–March. Among all 493 outbreaks, a bimodal temporal distribution was observed. The 275 (56%) outbreaks that started during June–August were predominantly caused by Cryptosporidium, whereas the 46 (9%) that started in March were predominantly caused by an unidentified etiology or pathogens other than Cryptosporidium. Negative binomial regression analysis indicated that during 2000–2007, the annual number of outbreaks caused by Cryptosporidium increased by an average of 25% (95% confidence interval [CI] = 7%–45%) per year. No significant trend was found after 2007.¶¶ Poisson regression analysis indicated that during 2000–2014 the annual number of outbreaks caused by Legionella increased by an average of 13% (95% CI = 6%–21%) per year, and the annual number of Pseudomonas folliculitis outbreaks (a total of 41 outbreaks during 2000–2014) decreased by an average of 22% (95% CI = 14%–29%) per year.*** [Source: CDC MMWR]