ATLANTA (CNN) — Clear water is not always a sign of clean water — or so suggest two new reports on water-associated disease outbreaks published Thursday by the US Centers for Disease Control and Prevention.
In 2013-14, a total of 42 drinking-water-associated outbreaks caused by infectious pathogens, chemicals or toxins were reported to the CDC from 19 states.
“The number of drinking water outbreaks has increased from 32 in 2011-2012,” said Kathy Benedict, lead author of the report and an epidemiologist in CDC’s Waterborne Disease Prevention Branch.
“This may be due to a true increase in disease, better reporting or changes in capacity in states to do surveillance.” Legionella caused more than half — 57 percent — of the outbreaks, 88 percent of the hospitalizations and all 13 deaths, according to the CDC.
Though water systems frequently “chlorinate before they distribute,” Subra explained, in some cases, the level of chlorination “isn’t sufficient to make it all the way to the end of this distribution system.” “So if these bacteria are in there and don’t get properly treated before they leave the plant … then the bacteria grows again and causes the people in the farthest regions of the distribution system to become contaminated and to become ill,” Subra said.
Waterborne disease During the same 2013-14 time frame, 15 outbreaks associated with an environmental exposure to water contaminated with harmful pathogens, chemicals or toxins were reported to the CDC by 10 states.
An additional 12 outbreaks caused by undetermined exposure to contaminated water were reported by eight states during the 2013-2014 period.
Benedict said outbreaks associated with environmental exposure to water increased from eight outbreaks in 2011-2012, while no change occurred in undetermined exposure outbreaks.
For the combined environmental and undetermined disease outbreaks, Legionella was responsible for 63 percent of the illnesses, 94 percent of hospitalizations and all deaths.
“So you have chemical contamination and bacterial contamination that you weren’t looking out for historically that are also now contaminating the water and causing severe health impacts to the community.” Though environmental scientists figured these issues were happening, there was no testing to verify them and no requirements at the federal or state level that tests be done by water systems.