Potentially Deadly E. Coli
Outbreaks Increase In
Public Pools And Lakes
NEW YORK (Reuters Health) -- The bacterium E. coli O157:H7 was responsible for a higher number of outbreaks of waterborne disease in swimmers during 1995-1996 compared with previous years, according to the Centers for Disease Control and Prevention (CDC).
The potentially life-threatening bacterium, commonly associated with disease outbreaks due to consumption of undercooked meat, can also cause illness when found in recreational pools or lakes.
In 1995 and 1996, there were 37 reported US outbreaks of illness associated with swimming in pools, lakes or other bodies of water. A total of 9,129 people became ill and six died. All six deaths were caused by amebic meningoencephalitis " a rare disease associated with Naegleria infections.
The number of outbreaks caused by bacteria increased from four in past years to 10, with 6 outbreaks linked to O157:H7. One of these outbreaks was caused by inadequate chlorination of a pool, and five cases were associated with contaminated lakes.
The number of outbreaks associated with gastroenteritis, or diarrheal illness, was greater in 1995-1996 than in previous years " 22 compared with 13 to 14 per year in 1989 to 1994. While the number of outbreaks due to parasites decreased from 10 to 7, two outbreaks caused by the parasite Cryptosporidium caused illness in more than 8,000 people.
Five of the six outbreaks associated with Cryptosporidium occurred in pools, which contain chlorine levels inadequate to kill the oocysts of the parasite, which spread the disease. Pool filtration systems that contain sand or other material may also not remove the oocysts, which can be accidentally swallowed while swimming.
"Prevention efforts have focuses on providing adequate bathroom facilities, including diaper-changing areas, at recreational areas and on limiting the numbers of swimmers per unit area,'' according to the CDC. "An additional important measure, although difficult to enforce, is to prevent persons (especially young, nontoilet-trained children) from entering recreational water if they are either experiencing or convalescing from a diarrheal illness.''
SOURCE: CDC Surveillance Summaries 1998;47:SS-5.