Primary amebic meningoencephalitis (PAM) — most often caused by the free-living amoeba Naegleria fowleri and sometimes called the “brain-eating amoeba” in the press — is rare but devastating. In 2025 Kerala has seen an unusual spike in cases, prompting public-health alerts and renewed attention to how this infection spreads and how to reduce risk. This article explains what Naegleria fowleri is, how PAM develops, current treatments, practical prevention tips, and answers frequently asked questions.
What is Naegleria fowleri and what is PAM?
Naegleria fowleri is a microscopic, free-living amoeba that thrives in warm freshwater (lakes, rivers, hot springs), warm discharge water and poorly-maintained or under-chlorinated pools. It does not infect people by drinking contaminated water — infections occur when water containing the amoeba enters the nose, travels along the olfactory nerve, and reaches the brain, causing primary amebic meningoencephalitis (PAM). PAM rapidly destroys brain tissue and is often fatal.
Why the sudden attention — the Kerala outbreak
In September 2025 Kerala reported a sharp increase in PAM cases compared with previous years. State health briefings and international outlets have reported roughly 60–70 confirmed cases and around 19 deaths so far this year, with multiple clusters across districts and cases affecting a wide age range (infants through elderly). Officials have issued health alerts, stepped up testing of meningoencephalitis cases for Naegleria, and accelerated public warnings about freshwater exposure. This surge is notable because, globally, PAM is extremely rare but almost always severe — and clusters like this are uncommon.
How does Naegleria infection happen? (simple timeline)
Exposure — warm freshwater containing N. fowleri gets forced up the nose (e.g., diving, jumping into water, underwater swimming, or using unsterile water for nasal rinsing).
Entry & migration — the amoeba attaches to nasal mucosa, migrates along the olfactory nerve through the cribriform plate into the brain.
Disease onset (PAM) — initial symptoms appear within about 1–12 days (commonly 2–7 days) and rapidly progress: headache, fever, nausea/vomiting → stiff neck, altered mental status, seizures → coma and death if not treated early. PAM can progress over a few days.
Symptoms to watch for
Early signs mimic common infections (so they can be missed):
Rapid progression may follow: confusion, hallucinations, seizures, loss of balance, altered consciousness. If someone has recent freshwater exposure and develops these symptoms, seek emergency medical care immediately and tell clinicians about the exposure — early suspicion is critical.
Diagnosis — why it’s hard and what doctors do
PAM resembles bacterial meningitis clinically. Diagnosis involves:
Rapid clinical suspicion based on symptoms + history of freshwater nasal exposure.
Cerebrospinal fluid (CSF) analysis and microscopy, PCR or specialized lab testing to detect Naegleria.
Because the disease progresses quickly, many health systems now test suspected meningoencephalitis cases for Naegleria to catch cases earlier. Kerala authorities said they are testing every meningoencephalitis case for Naegleria to enable early therapy.
Treatment — aggressive, multidisciplinary, but outcomes remain challenging
There is no single guaranteed cure for PAM, but aggressive, early, multi-drug therapy and intensive supportive care have produced very rare survivors. Treatment approaches used in survivors include high-dose amphotericin B, miltefosine (an anti-amoebic agent repurposed from antiparasitic use), rifampicin, azithromycin and other agents, alongside measures to control intracranial pressure (brain swelling). Kerala hospitals have increasingly used miltefosine as part of early, aggressive regimens and multidisciplinary care, which providers say has improved survival compared with historical averages — but PAM is still highly lethal overall. If you suspect exposure and symptoms, immediate hospital evaluation is essential.
Why warm water and why are outbreaks seasonal?
N. fowleri thrives in warm freshwater. In hot months water temperatures rise, creating favorable conditions for the amoeba to multiply in shallow, stagnant or slow-moving bodies of water, or in warm parts of man-made systems (poorly chlorinated pools, spa jets, heated discharge water). That’s why most PAM cases occur in summer months or in warm climates. When states or regions experience clusters, it’s usually tied to environmental conditions or specific water sources.
Practical prevention tips (what you can do)
Because PAM requires water to enter the nose, the most effective prevention measures focus on preventing water from going up the nose:
Avoid jumping/diving into warm freshwater (lakes, ponds, slow rivers) especially in hot months or where water is stagnant.
Avoid submerging your head in untreated warm freshwater — prefer chlorinated, properly maintained pools and hot tubs.
Use nose clips if you must be in warm freshwater and want extra protection.
Do not use tap water for neti pots or nasal irrigation unless it has been boiled for at least 1 minute and cooled, or treated to be sterile. (Simple faucet filtration or room-temperature tap water is not safe for nasal rinsing.)
Maintain pools and spas with adequate chlorine levels and follow public-pool guidelines.
Avoid stirring up sediment in shallow, warm freshwater where amoebae may concentrate.
Kerala authorities have specifically warned people to avoid bathing in or swimming in suspected contaminated water bodies and to report unusual febrile neurological illness after freshwater exposure.
Public health response in Kerala (what officials are doing)
Local and state health departments typically respond by: confirming cases with laboratory testing, issuing public advisories, sampling suspected water sources, tracing exposure sites, increasing clinical awareness (test all meningoencephalitis cases), and coordinating treatment resources in referral hospitals. In Kerala’s 2025 surge the state health ministry has raised alerts, expanded testing for Naegleria in suspected meningitis cases, and advised people to avoid risky freshwater exposures while investigations continue.
Risk perspective — how common is PAM?
PAM is extremely rare worldwide: only a small number of cases occur globally each year, although case counts vary by region and reporting. Historically, survival has been very low, but early detection and aggressive treatment have produced more survivors in some recent clusters. Still, because the infection progresses very quickly, prevention is by far the most important public-health measure.
What if someone has symptoms after freshwater exposure?
Seek emergency medical care immediately. PAM progresses rapidly.
Tell clinicians about any recent freshwater exposure (where and when, whether nasal irrigation was used, whether the patient dove or submerged head). That information prompts the lab to test CSF for amoebae and clinicians to consider early anti-amoebic therapy.
Do not delay because early suspicion changes management and may improve chances.
FAQs (frequently asked questions)
Q1: Is this contagious — can I catch PAM from another person?
No. PAM is not spread person-to-person. The infection requires direct entry of contaminated water into the nose; casual contact, touching, or drinking contaminated water does not transmit the disease.
Q2: Can I get infected by drinking contaminated water?
No — swallowing water containing N. fowleri is not a route for PAM. The amoeba needs access to the nasal passages to reach the brain. The risk comes from water entering the nose (swimming, diving, nasal irrigation).
Q3: Are pools safe?
Properly chlorinated and maintained public or private pools are considered safe. Under-chlorinated, poorly maintained pools or warm recreational water that is not disinfected can pose risk. Follow pool maintenance guidelines and public-health advisories.
Q4: Is boiled or filtered tap water safe for nasal rinses?
Use only sterile, distilled, or previously boiled (and cooled) water for neti pots/nasal irrigation. Boil water for at least 1 minute (longer at higher altitudes) and let it cool, or use water labeled sterile. Standard faucet water or simple consumer filters (like pitchers) do not guarantee sterility for nasal use.
Q5: What drugs treat PAM?
No single agent is guaranteed to cure PAM. Treatment typically uses multiple agents (intravenous amphotericin B, miltefosine, rifampicin, azithromycin, etc.) plus intensive care for intracranial pressure. Early diagnosis and a rapid, multi-drug treatment plan can improve the odds in rare survivors. Health authorities in Kerala have reported using miltefosine as part of frontline therapy.
Q6: Who is most at risk?
Anyone whose nose is exposed to contaminated warm freshwater can be at risk. Historically most cases have been associated with children and young adults who swim in freshwater, but Kerala’s cluster has included infants through older adults. Risk increases with warm, shallow, stagnant water and activities that force water up the nose.
Bottom line — practical takeaways
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Disclaimer:
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
