Brazos River (File)

WACO (June 14, 2012)—The Brazos River Authority Thursday urged those who swim in Central Texas lakes and rivers to be aware the health risks that come with swimming in or around stagnant or slow-moving water, which can harbor a dangerous microorganism.

An amoeba that thrives in low levels of warm, fresh, slow-moving or stagnant water called naegleria fowleri can cause primary amebic meningoencephalitis or PAM, which occurs when the amoeba is forced into nasal passages as a result of diving or jumping into the water or from water skiing.

The amoeba makes its way into the brain and spinal cord, destroying brain tissue.

Symptoms of the infection, which usually kills within in week, include severe headache, high fever, stiff neck, nausea, vomiting and seizures.

Fortunately the amoeba is rare.

Between 2000 and 2010, there were 10 confirmed cases of PAM in Texas, the river authority said and none has been diagnosed in the state since the beginning of 2011.

Only a few hundred cases have been reported worldwide over the last three decades, the river authority said.

The best way to prevent infection is to wear nose clips or to hold the nose shut while jumping into the water.

The amoeba is often found in soil, so it’s best to avoid stirring up underwater sediment, the river authority said.