A deadly brain-eating microbe was found in the water Texas’s water supply. The US state has since issued a warning to thousands of residents about using tap water.

The microbe was first discovered after a six-year-old boy contracted the microbe and died earlier this month. The boy died in Lake Jackson. Soon afterwards tests were carried out on the water system and confirmed the presence of Naegleria fowleri.

Eight communities had initially been warned on Friday not to use tap water for any reason except to flush toilets, while authorities distributed bottles of water to households.

Residents were told to boil tap water before drinking it or using it for cooking. And ensure water does not go up their nose while bathing, showering or washing faces. They were also advised not to allow children to play with any devices that might accidentally spray water up their nose.

Officials lifted that warning on Saturday, but the advice on boiling water remains in place for Lake Jackson’s 27,000-plus residents.

Naegleria fowleri is commonly found in warm freshwater and soil, according to the US Centers for Disease Control and Prevention (CDC). It usually infects people when contaminated water enters the body through the nose.

From there it travels to the brain and can cause a rare and debilitating disease called primary amebic meningoencephalitis. The infection is usually fatal.