Public-health officials suspect that a local woman died this week from an extremely rare but almost always fatal infection caused by a brain-eating amoeba.

Dr. Eric McDonald, medical director of the county’s Epidemiology and Immunization Services Branch, confirmed Friday that preliminary testing indicates the 24-year-old resident was infected by the organism, called naegleria fowleri.

(Aaron Atencio)

Officials in Yuma County, Ariz., said on the same day that the woman swam in the Colorado River at Martinez Lake and Fisher’s Landing the week before her infection.


The CDC confirmed Monday that the infection was caused by the amoeba.

Per medical privacy regulations, health officials are not identifying the victim, who died Monday.

According to the CDC, naegleria fowleri are microscopic, single-celled animals that move by twitching fingerlike projections known as pseudopods. They live in soil and warm fresh water.

From 1962 through last year, only 133 naegleria fowleri cases were reported nationwide. Three of those patients survived.


Generally, the amoebas live in muck at the bottom of lakes and ponds and consume bacteria found in the environment.

However, people can become infected when one or more of the amoebas enter the nasal passages — usually when a person is swimming or diving into shallow or stagnant water. There are no indications of infection occurring from drinking contaminated water, public health officials note.

Those experts also assure the public that the amoebas are not contagious.

Naegleria fowleri makes its way to the brain by traveling up nerve endings that reach into the nasal passages. Once there, the micro-organism uses sucker-like cups on its surface to consume the brain’s gray matter, said Dr. Francine Marciano-Cabral, a professor of microbiology and immunology at Virginia Commonwealth University who has studied this type of amoeba for more than 30 years.


“Once it reaches the brain, it divides very rapidly,” about once every eight hours when exposed to warm temperatures, Marciano-Cabral said.

This rapid growth causes severe brain swelling and initial symptoms such as headache, fever, nausea and vomiting one to seven days after infection. Later symptoms include loss of balance, seizures and hallucinations, according to the CDC.

Patients usually die within five days after the onset of symptoms.

Infections can be treated with a new drug called miltefosine, but catching the problem soon enough is very difficult because early symptoms are similar to those of bacterial meningitis — and because the time from first symptoms to death can be so short.


Marciano-Cabral said the amoeba is most commonly found in fresh water, such as lakes and ponds.

Municipal water supplies and swimming pools, which are typically sanitized with chlorine, are usually not a hospitable home for naegleria fowleri. But if standard disinfection procedures are not followed, then the amoeba can survive.

In July, the Louisiana Department of Health and Hospitals confirmed that the micro-organism was discovered in a parish water system near New Orleans. In 2011, a man in that area was found to have been killed by the amoeba after using a device called a “neti pot” to clean his sinuses.

On Aug. 13, an Oklahoma man died from the effects of a naegleria fowleri infection after swimming in a lake.


In California, the amoeba killed a 21-year-old Bishop resident in May after she swam in a privately owned but unspecified body of water.

According to the California Department of Public Health, there have been seven cases in the state since 1971. Six were fatal.

The relative risk of becoming infected is minute. There have only been 35 reported infections in the United States during the past 10 years, compared with 34,000 drownings, according to the CDC.

Since the 1960s, when the amoeba was first identified, scientists have tried to determine why so few people exposed to the parasite end up getting sick.


“Almost every single person has antibodies in their blood which indicate they were exposed at some point in time to the amoeba, but they didn’t die from it,” Marciano-Cabral said.

It could be that only an encounter with a large number of amoebas all at once causes infection, she said. Or, perhaps a specific subspecies of the amoeba is invasive while its cousins are benign.

Because millions of Americans swim in rivers and lakes every year, the CDC recommends limiting the amount of water that enters the nose during those activities.

Wearing a nose clip or holding the nose closed when under water can help, as can keeping the head above water, especially in hot springs.


Swimmers also are advised to not dive into warm, shallow water and to not stir up the mucky bottom of such bodies of water.