Anthrax has killed at least two gorillas and two chimpanzees in southeastern Cameroon, prompting fears that the highly infectious disease could spread to humans living nearby, government officials said on Tuesday.

“Analysis of samples taken from the dead animals indicates that the principal cause of their death is anthrax, a highly contagious disease to humans,” the central African country’s Ministry of Forestry and Wildlife said in a statement.

It was the first time that a gorilla had been reported to have died from anthrax, which occurs when animals absorb bacterial spores that can live for decades in dry soil while they eat remnants of vegetation, officials said.

The wildlife ministry warned people living in the northern belt of the Dja nature reserve not to touch or eat any dead monkeys but rather to burn or bury them immediately.

Anthrax can kill humans if the bacteria enters through a cut on the skin, is inhaled, or ingested through contaminated meat. If ground into fine particles, anthrax spores can cause respiratory failure and death when inhaled.

A wildlife ministry official said the primates had probably died between November and December last year but authorities had had to send samples to Germany to determine the cause of death.