DNR weighs options for brain-eating amoeba

State officials are considering whether to test more lakes, put up warning signs and launch a public-awareness campaign after a Missouri resident who swam at a southern Iowa lake recently died after being infected by a brain-eating amoeba.

“We’re having those discussions about what happens next,” said Tammie Krausman, a spokesperson for the Iowa Department of Natural Resources. “Our general philosophy is making sure we tell you the risks and try to weigh them. We want you to be focused on the higher risks.”

Drowning is one of those risks. From 2010 to 2020, the state averaged about 30 unintentional drowning deaths each year, according to Iowa Department of Public Health data.

And the state monitors its recreational beaches for bacteria concentrations and algae toxins, which can cause infections and skin irritation. Last week, the DNR said people should avoid swimming at 12 of those beaches because of elevated levels of those bacteria and toxins.

The beach of Lake of Three Fires near Bedford remains closed as tests of its water are pending for Naegleria fowleri, an amoeba that eats bacteria in lake sediment but can kill people if it gets deep into their noses. Infections are rare: There have been about 150 document infections in the United States in the past 60 years, although research suggests that many might go undetected. Four people in the country are known to have lived after being infected.

Someone from Missouri who recently swam at the lake died July 7 — one day after tests confirmed the person was infected by the amoeba.

The amoeba most often afflicts children, but the Missouri Department of Health and Senior Services has declined to identify the age and gender of the person who recently died.

“Because these cases are so incredibly rare and out of respect for the family, we do not intend to release additional information about the patient which could lead to the person’s identification,” said Lisa Cox, a spokesperson for the department.

The U.S. Centers for Disease Control and Prevention is testing water from Lake of Three Fires for the presence of the amoeba. If confirmed, it would be the first suspected case of someone being infected by it in Iowa.

Most of the documented infections have been in southern states — Texas and Florida account for nearly half of them — but they have also happened as far north as Minnesota, according to the CDC. The amoeba is most prolific when water temperatures reach the high 70 degrees and warmer.

The CDC does not generally recommend testing rivers and lakes for the amoeba because it’s assumed to be widely distributed and there is no confirmed relationship between its water concentrations and risk of infection.

Annual warnings about the amoeba are common in southern states, and public officials have posted signs at public swimming areas that tell of its presence.

Krausman said the DNR will decide how it will proceed after tests of Lake of Three Fires water are complete.