COOKEVILLE, Tenn., Aug. 22 (UPI) -- A U.S. study suggests cooling towers on top of many commercial buildings may hold high numbers of infected amoebas.
Researchers suggest such infected amoebas constitute a threat to human health, as illustrated by the 1976 outbreak of Legionnaires' disease.
Sharon Berk of Tennessee Technological University and colleagues sampled 40 cooling towers in hospitals, universities and industries, as well as 40 natural environments -- lakes, rivers, creeks and ponds. They found infected amoebas in 22 of the cooling towers, but in only three of the natural samples.
"The bacteria responsible for Legionnaire's disease use amoebas as a host, as do many related bacteria," said Berk, a TTU biology professor.
The bacteria can then "hijack" the amoeba's cellular machinery and multiply profusely, according to Berk. Eventually the amoeba swells and bursts like a balloon, releasing the bacteria by the hundreds.
The researchers said it's possible other amoeba-associated microorganisms, such as those found in cooling towers in the study, may be unrecognized causes of other respiratory disease.
The new study appears in the online edition of the journal Environmental Science & Technology.
