Kerala confronts rising brain-eating amoeba cases with aggressive testing and water-safety measures
Public health officials say early detection and targeted guidance are helping survival rates as wells and ponds dominate daily life in the state.
On the eve of the Onam festival in Kerala, Sobhana, a 45-year-old Dalit woman who bottled fruit juices in Malappuram district, lay shivering in the back of an ambulance as her family rushed her to a medical college hospital. What began as dizziness and high blood pressure days earlier escalated with alarming speed into fever, shivers and ultimately unconsciousness. On September 5, the main Onam day, Sobhana died from an infection caused by Naegleria fowleri, the brain-eating amoeba. The organism typically enters the nose during swimming in warm freshwater and rapidly destroys brain tissue. In Kerala this year, more than 70 people have been diagnosed and 19 have died, with patients ranging from a three-month-old to a 92-year-old man.
Naegleria fowleri causes primary amoebic meningoencephalitis, a near-fatal brain infection. It is extraordinarily rare in most parts of the world, and most doctors may never encounter a case in a lifetime. Globally, 488 cases have been reported since 1962, with about 95% of victims dying. Kerala began detecting cases in 2016, usually one or two a year, but the current year has seen a substantial rise in diagnoses.
Survival in Kerala appears to be improving as detection and treatment advance. Last year there were 39 cases with a 23% fatality rate; this year, nearly 70 cases have been reported with about a 24.5% mortality. Doctors attribute the better outcomes in part to state-of-the-art laboratories and a more aggressive approach to testing and early diagnosis. Aggressive, customised drug regimens that combine antimicrobials and steroids aimed at the amoeba can save lives when started promptly, physicians say.
In Kerala, public health laboratories can detect the five major pathogenic types of free-living amoebae, though only a handful cause disease in humans. The state relies heavily on groundwater and natural water bodies, making water sources a daily concern. Ponds and wells are ubiquitous: Kerala has nearly 5.5 million wells and about 55,000 ponds, with millions drawing drinking water from wells alone. That ubiquity makes mass chlorination and blanket bans impractical, even as officials emphasize prevention. Some infections have occurred in people bathing in ponds, others from swimming in pools, and even through nasal rinsing with water used in religious rituals. Authorities stress practical steps: keep noses protected while in or around water, use clean warm water for nasal applications, and avoid unsafe ponds. They advise keeping children away from garden sprinklers in hot weather and reducing exposure to untreated water.
Public health campaigns have tried to reach a wide audience. In a single August campaign, 2.7 million wells were chlorinated, and local governments posted warning signs around ponds to deter swimming or bathing. Regulators have invoked the Public Health Act to enforce regular chlorination of pools and water tanks, though chlorination of every pond remains logistically unfeasible. Officials emphasize awareness over outright bans, noting that some infections occur from nasal rinsing with untreated water or from swimming in polluted water sources.
Some experts caution that enforcing safe-water practices in a densely populated, water-reliant state is a complex challenge. They point to the need for sustained monitoring and public education to balance risk without provoking undue fear. Anish TS, a leading epidemiologist, notes that infections can occur in a variety of water settings, from ponds to pools to ritual practices that involve nasal exposure to water. He argues that control hinges on reliable testing and timely treatment rather than sweeping restrictions.
Climate change is adding another layer of risk. Warmer waters, longer summers and rising temperatures create conditions that favor Naegleria fowleri in tropical climates such as Kerala. A modest rise in water temperature could expand the amoeba’s range in the state, while pollution from water sources fuels bacterial growth that feeds the amoeba. Some past cases may have gone unrecognised, as identifying the cause can be challenging, complicating treatment decisions. Dr Kyle, a specialist in infectious diseases and cellular biology in the United States, cautions that current drug cocktails are sub-optimal and that data on which regimens are most effective remain limited. Nonetheless, for survivors, tailored treatment often makes the difference between life and death.
Kerala’s experience is drawing attention beyond its borders as researchers and public health officials consider how climate-driven shifts may alter the map of even the rarest infections. The state’s approach—enhanced laboratory capacity, rapid testing, targeted public messaging, and practical water-safety guidance—offers a model for other regions facing growing threats from climate change and waterborne pathogens. As the outbreak unfolds, officials say the priority remains preventing infection through safer water practices while ensuring swift, targeted medical care for those affected.
