India has issued a health alert after infections and deaths caused by a rare water-borne “brain-eating” amoeba doubled compared to last year in the southern state of Kerala.

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 Centers for Disease Control and Prevention (CDC) 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 percent of those affected.

Infections are “very rare but nearly always fatal”, the CDC notes.

The amoeba lives in warm lakes and rivers and is contracted by contaminated water entering the nose. It does not spread from person to person.

The World Health Organisation says that symptoms include headache, fever and vomiting, which rapidly progress 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.