A Florida boy is fighting for his life after doctors say he became infected with a brain-eating amoeba while swimming.

Caleb Ziegelbauer who is at the age of 13, first started feeling ill five days after he went swimming with his family at the Port Charlotte Beach Park on July 1, Florida news station WBBH/NBC 2 reported. His symptoms included headaches, feeling disorientated and hallucinations, and he was then hospitalized at the Golisano Children’s Hospital.

Ziegelbauer has now been in hospital for more than two weeks, with family and supporters gathering outside wearing yellow—his favourite colour. They are holding out for his recovery.

The authority said there was a risk of being infected with Naegleria fowleri, which is common in all surface water worldwide. It added that people who live in warm-weather states “should assume there is a risk when entering all warm freshwater bodies.”

Steps for prevention might include holding one’s nose shut, wearing nose clips, and keeping the head above water in warm freshwater; avoiding putting one’s head underwater in hot springs and other untreated thermal waters; avoiding water-related activities in warm freshwater during high water temperatures; and avoiding stirring up sediment in the water, according to the CDC.

The CDC adds that the above recommendations “make common sense but are not based on any scientific testing since the low numbers of infections make it difficult to ever show that they are effective.”