MIAMI -- Family members of a 12-year-old Florida boy who was infected by a rare and deadly amoeba say the organism that was attacking his brain is gone.

According to a Facebook page set up for Zachary Reyna, doctors told family members Wednesday morning that antibiotics defeated the infection. Although tests showed negative activity from the amoeba, the Facebook post says the boy suffered extensive brain damage.

Reyna was infected with Naegleria fowleri, a microscopic single-celled living amoeba that is commonly found in freshwater lakes, ponds and rivers. State health officials say it can cause a rare brain infection called primary amebic meningoencephalitis (PAM) that destroys brain tissue and is usually fatal.

Family members said Reyna was infected while knee boarding with friends in a ditch near his family’s southwest Florida home on Aug. 3. He is being treated at Miami Children’s Hospital.