Health authorities in the southern Indian state of Kerala have issued a health alert after infections and deaths caused by a rare water-borne “brain-eating” amoeba, Naegleria fowleri.

The infection, known as Primary Amoebic Meningoencephalitis (PAM), is contracted when the amoeba, which thrives in warm freshwater, enters the body through the nose while a person is swimming, bathing, or diving. Once in the body, it travels to the brain, causing a severe and rapidly fatal infection.  It does not spread from person to person.

Numbers are still tiny but Altaf Ali, a doctor who is part of a government task force to arrest the spread, told AFP that officials were “conducting tests on a large scale across the state to detect and treat cases”.

Officials reported 19 deaths and 72 infections of the Naegleria fowleri amoeba this year, including nine deaths and 24 cases in September alone.

Last year, the amoeba killed nine people out of 36 reported cases.

The US Centres for Disease Control and Prevention says it is often called a “brain-eating amoeba” because it can “infect the brain and destroy brain tissue”.

If the amoeba reaches the brain, it can cause an infection that kills over 95 per cent of those affected, infections are “very rare but nearly always fatal”, the CDC notes.

The World Health Organisation says that symptoms include headache, fever and vomiting, which rapidly progresses to “seizures, altered mental status, hallucinations, and coma”.

“It’s worrying that new cases this year have emerged from across the state, as opposed to specific pockets in the past,” Ali said.

Since 1962, nearly 500 cases have been reported worldwide, mostly in the United States, India, Pakistan, and Australia.