Last Updated:
Dr Aravind R said while Kerala has managed to reduce the mortality rate of even the deadliest Naegleria infections, misinformation remains a concern
Dr Aravind R, head of the department of infectious diseases at Government Medical College, Thiruvananthapuram, Kerala.
Kerala’s sudden surge in cases of amoebic meningoencephalitis (AME)—a condition often linked in popular imagination to the so-called “brain-eating amoeba”—is not just a matter of chance, but of stronger disease surveillance, Dr Aravind R, head of the department of infectious diseases at Government Medical College, Thiruvananthapuram, Kerala, has told News18.
Warning against misinformation, Aravind said: “Of 103 AME cases detected in Kerala over the last two years, only 11 were due to Naegleria Fowleri—the real brain-eating amoeba—and all others were due to free-living amoeba, which led to chronic illness but have higher chances of survival.”
Recommended Stories
This means only nine per cent patients suffered the pathogen that had the capacity to eat brains, while the remaining 91 per cent had an infection from the relatively milder version, which is most likely treatable, unless the person has weak immunity or prevailing medical history.
Even though increased case detection is a cause of worry, “more worrying is the misinformation that brain-eating amoeba infection is spreading in Kerala”, he said.
What Causes AME, How Does It ‘Eat’ The Brain?
AME cases are usually caused by Naegleria Fowleri, which leads to primary AME with a “98 per cent case fatality rate”, as well as another free-living amoeba such as acanthamoeba, Balamuthia, sappinia, vermamoeba and paravahlkampfia, which cause granulomatous AME.
Naegleria is often referred to as ‘brain-eating amoeba’ due to “its ability to invade and digest brain tissue resulting in catastrophic presentation and rapid progression to death in the majority of the cases”.
The clinical presentation of amoebic meningoencephalitis is not easy to differentiate from meningoencephalitis [ME] caused by bacterial or viral infections. “The classic symptoms such as fever, headache, neck pain and alteration of sensorium remain the same.”
Hence, a high index of clinical suspicion and microbiology skill is necessary to diagnose the disease.
Kerala’s Surveillance & Treatment Edge
Multiple studies from north and east India, Aravind pointed out, show that “amoebic meningoencephalitis rather than being a rare disease is a rarely diagnosed disease”.
Following repeated Nipah outbreaks, Kerala had strengthened its ME surveillance systems. “Between 2016 and 2023, the state was detecting only one or two cases of AME every year, with 100 per cent mortality.”
However, in 2024, Kerala proactively started looking for etiological diagnosis in undiagnosed cases of AME where the usual bacterial and viral tests were negative. “This strategy resulted in detection of eight cases of AME by July 2024 with 50 per cent survival rate,” Aravind said.
On analysing those cases, the team found that “if diagnosis was made within three days of symptom onset, chances of survival were high”. Based on this, Kerala released technical guidelines in July 2024—the first state in India to do so.
Patients first undergo cerebral spinal fluid (CSF) testing followed by microscopy and molecular testing.
“Adoption of this treatment protocol coupled with active case surveillance even in patients without obvious water exposure resulted in diagnosis of 39 cases in 2024 with 24 per cent case fatality rate. This remarkable feat of lowering mortality was made possible by early diagnosis and administration of drugs as per state protocol,” he explained.
The state public health lab in Kerala in 2025 has established a molecular diagnostic facility for identifying the species of amoeba which helps in optimising the treatment regimen. “Through this, the turnaround time for molecular confirmation was reduced from three weeks to two days.”
Once the variant is identified, the treatment can be customised. All these factors contributed to an increase in case detection happening in 2025 compared to 2024.
Identifying the source of infection is easy in case of AME due to naegleria, as incubation period is only 7-14 days. However, in case of infection caused by other variants of amoeba, incubation period can vary between weeks to months.
“Globally, etiological diagnosis of this disease is identified in only 40-50 per cent of meningoencephalitis cases, while in India the number drops to 30 per cent.”
This means, 70 per cent of remaining meningoencephalitis cases go undiagnosed.
One Health Approach
Aravind, who was also a member of the State Medical Board on Covid-19 and the State Expert Committee on Covid-19, said Kerala has since adopted a “One Health” action plan to prevent and manage AME.
“In August 2024, a technical workshop was conducted in Kerala to explore preventive methods keeping principles of One Health in mind. Following this a One Health based multi-pronged action plan to optimise the prevention, diagnosis and treatment of AME in Kerala focussing on public awareness campaigns, enhancing diagnostic capacity, active case surveillance, drug availability, research, environmental surveillance and hot spot mapping.”
This included proactive testing for AME “even in patients without an epidemiological link,” a strategy unique to Kerala. As a result, around 70 cases were diagnosed in 2025.
Kerala’s abundance of water bodies has complicated prevention efforts. “Kerala abounds in waterbodies with around 55,000 ponds and close to 55 lakh open wells. As sources of some of the cases were tracked back to wells, a massive chlorination of wells campaign was undertaken across the state in August. The Public Health Act has been invoked to ensure that all swimming pools and water theme parks maintain adequate residual chlorine levels,” he said.
Falling Fatality, Rising Questions
Kerala has managed to reduce the mortality rate of even the deadliest Naegleria infections. “Active search for cases of AME and timely initiation of treatment with amphotericin, miltefosine, azithromycin, fluconazole and rifampicin has helped to bring down mortality even in Naegleria Fowleri AME to less than 30 per cent in Kerala,” Aravind said.
Still, he said, the question remains why the case numbers of a supposedly rare infection are increasing. “Can global warming be blamed for the surge in cases confined to one region alone?”
“Active search for AME in other parts of the country might give an answer to these questions. The lessons learnt from Kerala need to transcend boundaries as it seems as if AME rather than being a rare disease is a rarely diagnosed disease.”
About the Author
Himani Chandna, Associate Editor at CNN News18, specialises in healthcare and pharmaceuticals. With firsthand insights into India’s COVID-19 battle, she brings a seasoned perspective. She is particularly pass…Read More
Himani Chandna, Associate Editor at CNN News18, specialises in healthcare and pharmaceuticals. With firsthand insights into India’s COVID-19 battle, she brings a seasoned perspective. She is particularly pass… Read More
Kerala, India, India
September 22, 2025, 12:10 IST
Loading comments…
Read More
