On the eve of Onam, the most joyous festival in India's Kerala state, 45-year-old Sobhana lay shivering in the back of an ambulance, drifting into unconsciousness as her family rushed her to a medical college hospital.
Just days earlier, the Dalit woman, who earned her living bottling fruit juices in a village in Malappuram district, had complained of nothing more alarming than dizziness and high blood pressure. Doctors prescribed pills and sent her home. But her condition spiralled with terrifying speed: uneasiness gave way to fever, fever to violent shivers, and on 5 September - the main day of the festival - Sobhana was dead.
The culprit was Naegleria fowleri - commonly known as the brain-eating amoeba - an infection usually contracted through the nose in freshwater and so rare that most doctors never encounter a case in their entire careers. We were powerless to stop it. We learnt about the disease only after Sobhana's death, says Ajitha Kathiradath, a cousin of the victim and a prominent social worker.
In Kerala this year, more than 70 people have been diagnosed and 19 have died from the brain-eating amoeba. Patients have ranged from a three-month-old to a 92-year-old man.
Normally feeding on bacteria in warm freshwater, this single-cell organism causes a near-fatal brain infection, known as primary amoebic meningoencephalitis (PAM). It enters through the nose during swimming and rapidly destroys brain tissue.
Kerala began detecting cases in 2016, and until recently, nearly all were fatal. A new study has found only 488 cases have been reported globally since 1962 - mostly in the US, Pakistan and Australia. And 95% of the victims have died from the disease.
But in Kerala, survival appears to be improving: last year there were 39 cases with a 23% fatality rate, and this year, nearly 70 cases have been reported with about 24.5% mortality. Doctors say the rise in numbers reflects better detection, thanks to state-of-the-art labs.
Cases are rising but deaths are falling. Aggressive testing and early diagnosis have improved survival - a strategy unique to Kerala, said Aravind Reghukumar, head of infectious diseases at the Medical College and Hospital in Thiruvananthapuram, the state's capital. Early detection allows customized treatment: a drug cocktail of antimicrobials and steroids targeting the amoeba can save lives.
Kerala's heavy reliance on groundwater and natural water bodies makes it particularly vulnerable, especially as many ponds and wells are polluted. Public health authorities have tried to respond at scale: in a single campaign at the end of August, 2.7 million wells were chlorinated.
Local governments have put up sign boards around ponds warning against bathing or swimming and enforced regular chlorination of swimming pools and water tanks. Yet, striking a balance between educating the public about real risks and maintaining daily life is challenging.
Scientists warn that climate change is amplifying the risk: warmer waters and rising temperatures create ideal conditions for the amoeba. As Kerala navigates these challenges, a holistic approach to safeguarding public health remains urgent.
