Summertime is here and for many, that means grabbing a floatie and jumping in the lake. But if you think lake swimming doesn't carry the dangers of the ocean, you may want to keep your head above the water.
Sure, you may not be swimming with sharks, but a deadly brain-eating amoeba is waiting to strike at any time.
Naegleria fowleri is microscopic, single-celled organism that naturally lives in the environment and thrives in heat, according to the Centers for Disease Control and Prevention. It is typically found in warm freshwater lakes, rivers and hot springs; and soil, including sediment at the bottom of lakes. In very rare cases, Naegleria fowleri has been found in poorly maintained swimming pools, splash pads and other recreational venues, the CDC said. The amoeba also has been found in tap water.
Naegleria fowleri is often called the "brain-eating amoeba" because it can infect the brain and destroy brain tissue.
People become infected when water containing Naegleria fowleri enters the nose, usually while swimming, diving or water-skiing. The amoeba migrates to the brain along the olfactory nerve where it begins to destroy tissue and cause the brain to swell. It can also trigger a fatal brain infection called primary amebic meningoencephalitis (PAM).
Brain infections caused by Naegleria fowleri are very rare but nearly always fatal. Typically, fewer than 10 people a year in the United States get PAM, the CDC said. More than 97% of people with PAM have died from the infection.
Early symptoms of PAM can include headache, fever, nausea and vomiting. PAM progresses rapidly and most people die within 1 to 18 days after symptoms begin. It usually leads to coma and death after 5 days.
As PAM progresses, symptoms can include stiff neck, confusion, lack of attention to people and surroundings, loss of balance and hallucinations.
Because the infections are so rare and hard to detect, diagnosis sometimes happens after a person has died, according to the CDC.
People do not get infected by drinking contaminated water. You cannot get PAM from swallowing water containing Naegleria fowleri, or from swimming in a properly cleaned, maintained and disinfected pool. The amoeba has also never been shown to spread from one person to another.
"It is safest to assume you can get a Naegleria fowleri infection anytime you go into a lake or other fresh water," the CDC said. "Take steps to prevent infection every time."
Most Naegleria fowleri infections have been linked to swimming in southern states. However, geographical areas where infections happen are changing. Since 2010, infections have been confirmed in Nebraska, Iowa, Minnesota, Indiana, Maryland, and northern California, according to the CDC.
Infections often happen when it's been hot for long periods, resulting in higher water temperatures and lower water levels.
To help protect yourself against a Naegleria fowleri infection, the CDC recommends:
• Hold your nose or wear a nose clip if you are jumping or diving into fresh water.
• Always keep your head above water when taking part in water-related activities in bodies of warm freshwater.
• Avoid putting your head under the water in hot springs and other untreated thermal waters.
• Don't dig in or stir up sediment in shallow water because the amoeba is more likely to live there.
• Use distilled or boiled tap water when rinsing your sinuses or cleansing your nasal passages.
Anyone who experiences symptoms of PAM after swimming in any warm body of water should contact a health care provider immediately.