Summer Swims Can Mean Disease from Untreated Water


At least 4,958 people were affected by recreational water contamination between 2000 and 2014 in the United States.

While going for a swim might be the ideal way to beat the summer heat, recreational waters, such as lakes, rivers, and oceans, could be dangerous if the water is not properly treated.

From 2000-2014, there were 140 outbreaks resulting from untreated water in 35 states and Guam, according to the CDC. Diseases from pathogens, toxins, or chemicals in the water affected at least 4,958 people, and killed 2.

Investigations were able to determine that 95 of the outbreaks were caused by infectious pathogens, with a majority of them infecting the intestines: 22% were caused by norovirus, 20% byE. coli,15% byShigella, and 13% byCryptosporidium, according to the CDC.

These 95 outbreaks resulted in 3,125 cases of infectious diseases, most of which were affecting the intestines: 47% were caused by norovirus, 12% byShigella, 10% byCryptosporidium, and 5% byE. Coli.

The remaining outbreaks were caused by Avian schistosomes, which resulted in 11% of the 3,125 cases, and a single outbreak ofNaegleria fowleri,which resulted in 2 deaths, according to the CDC.

The most common places for outbreaks were public parks and beaches, according to the CDC, and a majority of outbreaks occurred between June and August, with more than half occurring in July.

Being aware of the signs of water that is contaminated with pathogens, toxins, and chemicals can help families avoid unpleasant and dangerous diseases. The CDC recommends not swimming in a lake, river, or ocean if the water is discolored, foamy, smelly, or scummy. The CDC also advises against swimming if you are sick with diarrhea, and recommends being cautious in letting water enter the nose or mouth.

The CDC notes that the health of swimmers, animals, and the environment are all factors in preventing outbreaks, and experts in epidemiology, ecology, and veterinary science need to collaborate to alleviate outbreaks, and prevent the future spread of disease.

Some steps experts can take to prevent an outbreak include preventing and purifying contaminated water, regulating wildlife, properly testing water quality for bacteria and pollution, promoting a notification program for untreated water, and getting the Environmental Protection Agency involved when necessary, according to the CDC.

Swimmers should search for any related Beach Advisory and Closing Online Notification database for updates on water conditions for coastal, marine, and Great Lake beaches. For inland lakes, reservoirs, and ponds, the CDC recommends checking local advisories for updates on water conditions.


Graciaa DS, Cope JR, Roberts VA, et al. Outbreaks Associated with Untreated Recreational Water — United States, 2000—2014. MMWR Morb Mortal Wkly Rep 2018;67:701–706. DOI:

Related Videos
Related Content
© 2024 MJH Life Sciences

All rights reserved.