A Texas boy has become the sixth person this summer to die from brain eating amoeba.
Jack Herrara aged 12 died after his brain was attacked by the Naegleria fowleri amoeba after swimming in a lake; three of the other victims were in Florida and one was in Arizona.
Recent tests have shown that the brain-eating amoeba is present in Tucson's water supply, but experts say the microscopic bug does not pose any health risks because the water is chlorinated before distribution, which kills Naegleria fowleri before the water reaches the taps.
The U.S. Centers for Disease Control and Prevention (CDC) says Naegleria fowleri is found worldwide, most commonly in warm bodies of freshwater, such as lakes, rivers, hot springs, water discharged from industrial plants, poorly maintained and minimally chlorinated swimming pools and in the soil.
Between 1995 and 2004 only 23 infections were documented in the U.S. and though infection with Naegleria is very rare, it occurs most commonly during the dry, summer months, when the air temperature is hot, the water is warm, and water levels are low.
The CDC says the number of infections increase during heat waves.
The infection occurs when the amoeba enters the body through the nose usually when people are swimming underwater, diving, or doing water sports that result in water going up the nose.
The amoeba then travels to the brain and spinal cord where it destroys the brain tissue.
The signs and symptoms of Naegleria start 1 to 14 days after infection and include headache, fever, nausea, vomiting, and a stiff neck.
As the amoebae cause more extensive destruction of brain tissue this leads to confusion, lack of attention to people and surroundings, loss of balance, seizures, and hallucinations.