A child is critically ill with a severe brain infection possibly caused by an amoeba found in Lake Minnewaska in Pope County, Minnesota Department of Health officials said Tuesday.

State officials say they're investigating the case of primary amebic meningoencephalitis (PAM) caused by an amoeba called Naegleria fowleri typically found in freshwater and soil. They determined the child caught the infection after swimming in the lake.

The rare infection enters the body through the nose, according to MDH, and is more common in warm southern states, but can be found all over the world.

According to the Centers for Disease Control, once the amoeba enters the nose, it travels to the brain where it causes PAM, which is usually fatal.

Thirty-five cases were reported in the United States from 2005 to 2014, including two in Minnesota in 2010 and 2012. Both children, a 9-year-old boy and a 7-year-old girl, died after swimming in Lily Lake in Washington county.

State health officials say the amoeba is more likely to be found when water temperatures are high and levels are low.

MDH waterborne diseases unit supervisor Trisha Robinson said PAM is often difficult to diagnose with symptoms similar to meningitis. Symptoms include headache and vomiting.

Lake Minnewaska is still open to the public. Robinson said one case does not mean the lake is dangerous and will infect others.

"The amoeba is able to be found in all kinds of water," she said. "This does not mean that there should be any greater risk in this lake than anywhere else."

But she said people can take steps to avoid catching the disease.

"The only sure way that we can prevent this from happening is to avoid participation in freshwater activities," Robinson said. "Unfortunately this isn't necessarily realistic. So people can reduce the risk by keeping their head out of the water, using nose clips or holding the nose shut and avoiding stirring up sediment at the bottom of shallow freshwater areas."

Children's Hospitals and Clinics infectious disease pediatrician William Pomputius said those infected with PAM often succumb to the disease within days.

"I'm aware of perhaps three cases of documented survival out of well over 100 that have been reported in the literature," he said. "If even recognized quickly it is a very, very, very difficult infection to treat."