New Delhi: Kerala has a new health alarm. First it was Nipah, now it is brain-eating amoeba. Two new deaths were reported this week in Malappuram and Kozhikode. The state has recorded the largest-ever outbreak of primary amoebic meningoencephalitis, or PAM, in the world during 2024-25.
A total of 36 cases and nine deaths were reported in 2024. So far this year, 160 cases have been reported, of which at least 36 people have died. Kollam and Thiruvananthapuram have been the worst-hit districts, with a few cases reported in Kozhikode and Malappuram. What has added to the panic is that some recent victims reportedly had no known contact with contaminated water, which is said to be the main source of the brain-eating amoeba.
“It’s alarming,” said Dr Shareek PS, an infectious disease doctor in Thiruvananthapuram who has been involved in the care of brain-eating amoeba patients. “It’s the worst epidemic of brain-eating amoeba anywhere in the world. The good part is we could diagnose it on time. Things could have been far worse.” For an infection believed to have a death rate of about 97 per cent, it has been 23 per cent in Kerala this year.
PAM, or ‘brain-eating amoeba’, is caused by an amoeba called Naegleria fowleri. The organism has been detected in every country except Antarctica. Between 1965 and 2018, a total of 381 PAM cases were reported globally in scientific literature and to the US Centers for Disease Control. Reported cases increased by around 1.6 per cent each year from 1965 to 2016, according to a study published in the journal Clinical Infectious Diseases.
However, studies have also noted that officially reported cases of N. fowleri are an underestimation.
“The cases we know of only represent the tip of the iceberg,” Shareek said. He added that the insights from this epidemic go far beyond what is currently known about the disease in medical literature.
Kerala provides the ideal breeding ground for Naegleria fowleri. The organism thrives in freshwater lakes, hot springs, poorly chlorinated pools, and other water bodies that rapidly fluctuate in temperature because of thermal pollution—conditions that are found abundantly in the state with its many waterbodies.
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How do you get PAM?
People often dive or jump into ponds to cool off, but this can be dangerous. Contaminated water can enter the nasal cavity under pressure.
It can happen during swimming or diving, when using a neti pot with amoeba-infested water, or during religious ablutions. The amoeba then travels through the olfactory nerves (which help in the sense of smell) into the brain, causing severe inflammation and brain-fever-like symptoms that often lead to death.
Tracing the source of infection, though, isn’t always straightforward.
Shareek described one case where a man cleaned his wound with dirty water and developed brain-fever-like symptoms within weeks.
“It’s difficult to connect the dots,” he said.
Symptoms include fever, nausea, vomiting, neck stiffness, disorientation, and loss of consciousness. The time from exposure to symptoms ranges from one to 14 days. Drinking contaminated water does not cause infection.
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Diagnosis and treatment
Doctors say PAM should be suspected in any case of brain fever following recent exposure to freshwater. It is usually diagnosed through tests on cerebrospinal fluid (the fluid surrounding the brain and spinal cord). Intracranial pressure can rise dangerously high, which can lead to death.
For a disease with an extremely high fatality rate, catching it quickly can make all the difference. In one reported case, it was a child’s father who mentioned a history of swimming in a contaminated pool, a clue that led to the diagnosis and treatment.
“Early diagnosis is the key,” said Shareek.
Advanced tests (Rapid PCR) have helped detect the disease sooner and led to treatment with better outcomes. Studies show that patients diagnosed within nine hours to five days after symptoms appear have a better chance of recovery.
Miltefosine, an oral drug, has improved survival rates in recent outbreaks of PAM.
The other line of defence is prevention.
Doctors advise avoiding jumping or diving into stagnant or contaminated water, as water entering the nose under pressure increases infection risk. It is also advisable to keep the head above water while swimming. Chlorination is the key method to prevent PAM as the amoeba cannot survive in well-chlorinated water.
What Kerala is doing
The state government has been taking various measures to combat the epidemic. A multi-pronged approach has been launched, including public awareness campaigns, chlorination of water sources, and improved medical surveillance and treatment protocols.
The public is being advised to avoid swimming in stagnant or contaminated water and early detection is being prioritised through advanced testing under a protocol of One Health, a state programme that specifically addresses health risks and outbreaks caused by human, animal, and environmental interaction.
Updated treatment protocols, including drugs like miltefosine, have also helped keep the fatality rate down.
Dr Ashok Nataraj is a medical doctor and a TPSJ alumnus currently interning with ThePrint.
(Edited by Asavari Singh)