Rare waterborne infection noted in three deaths

State and federal health officials are warning people about common sense ways to avoid recreational water illness, in the wake of three deaths that have been connected to the rare waterborne illness known as primary amoebic meningoencephalitis.

A school-aged child from Central Virginia, a 16-year-old Florida girl and a Louisiana man have all died this summer from primary amoebic meningoencephalitis, which is caused by infection with the amoeba Naegleria fowleri. The amoeba travels through the nose to the brain, causing a severe and nearly always fatal form of meningitis.

In an interview with Infectious Disease News, Director of Epidemiology at the Virginia Department of Health Keri Hall, said that their office was notified about the child’s case to determine whether or not prophylactic antibiotics would be necessary for familial contacts, but diagnostic testing ruled out the need for prophylaxis.

Ways to prevent infection

Hall acknowledged that multiple media reports about these patients might prompt patients to ask their physicians about ways to avoid infection. In this situation, Hall said that clinicians should advise patients and parents about water safety, while also counseling about the rarity of this infection.

N. fowleri infections are very rare. Between 2001 and 2010, 32 infections were reported in the United States, according to CDC reports. Of those cases, 30 people were infected by contaminated recreational water and two people were infected by water from a geothermal drinking water supply.

“The best way to prevent recreational water illnesses is to keep germs out of the water in the first place,” Hall and colleagues wrote in a press release following reports of the boy’s death. Health officials noted “periods of no rain and very high temperatures” in Virginia likely led to spikes in the population of N.fowleri, which proliferates in the upper layer of sediment in the bottom of lakes and ponds with mud floors, and stagnant freshwater lakes, ponds, streams and rivers.

CDC materials note that symptoms of PAM are similar to those of bacterial meningitis. Initial symptoms of primary amoebic meningoencephalitis start 1 to 7 days after infection. The initial symptoms include headache, fever, nausea, vomiting and stiff neck. Later symptoms can include confusion, lack of attention to people and surroundings, loss of balance, seizures and hallucinations. After the start of symptoms, the disease progresses rapidly and usually causes death within 1 to 12 days. Hall said the severity of these illnesses underscores the importance of vaccination against the other, also potentially lethal forms of meningitis.

Healthy swimming

Health officials offered these tips for healthy swimming practices for clinicians and their patients:

• Don’t swim when you have diarrhea;
• Don’t swallow pool, lake, pond or river water;
• Practice good hygiene. Shower with soap before and after swimming;
• Wash your hands thoroughly after using the restroom or changing diapers;
• Take children on bathroom breaks or change diapers often;
• Change diapers in a bathroom, not at poolside or beachside;
• Avoid swimming, diving or other activities in obviously stagnant freshwater bodies when temperatures are high and water levels are low; and
• Hold your nose or wear nose plugs when underwater or when diving or swimming in hot, shallow freshwater bodies.

“The best way to avoid infection is to avoid getting water up in the nose, by not submerging their head, pinching their nose or even using nose clips,” Hall said during the interview.

The most common symptom of recreational water illness is diarrhea, which frequently is severe enough to result in hospitalization. Symptoms may not begin until a week or more after swimming. Another concern is the parasite Cryptosporidium, one of the most common waterborne disease agents. It is a chlorine-resistant parasite that can survive and be transmitted even in a properly maintained pool. – by Colleen Zacharyczuk

Herbert L. DuPont

This is a potential problem during the summertime when free-living amoebae can be found in standing water. The highest risk for this fatal infection is when people are diving into water or water skiing and go into the water head first. The distance from the nose to the base of the brain is quite short and microbes in water can literally be driven into brain across the cribriform plate separating the nose from the brain. Prevention is the important thing. Keeping the head above water should eliminate the problem.

–Herbert L. DuPont, MD
St. Luke’s Episcopal Hospital, Houston

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