AUSTIN (KXAN/NBC/CNN) — A 10-year-old girl died weeks after swimming in the Brazos River from a “brain-eating” ameba.

Lily Avant’s family told NBC affiliate KXAS that she was transferred to a Fort Worth hospital where doctors confirmed she contracted Naegleria Fowleri. Avant, who was from Whitney, had gone swimming over Labor Day and a week later got a fever.

Naegleria Fowleri usually infects people when contaminated water enters the nose and travels to the brain, where a rare and deadly infection called primary amebic meningoencephalitis, or PAM, can occur, according to the Centers for Disease Control. The ameba is most common in soil and warm freshwaters, such as lakes, rivers and hot springs.

The Texas Department of State Health Services told KXAS the ameba is common, but infections are not.

“We average less than one per year in Texas. However, it is extremely serious and almost always fatal. Since it’s so rare, we don’t know why a few people get sick while millions who swim in natural bodies of water don’t,” an agency spokesperson told KXAS. “Because the organism is common in lakes and rivers, we don’t recommend people specifically avoid bodies of water where people have contracted the illness.”

Last year, a man died from the same type of ameba after visiting a Waco surf park.