What is ‘Brain-eating amoeba’ which kills 19 in Kerala

September 18, 2025

Kerala is battling a deadly outbreak of a rare brain infection caused by the so-called “brain-eating amoeba”. At least 69 confirmed cases of Primary Amoebic Meningoencephalitis (PAM) have been reported in the state this year, with 19 people losing their lives. The disease, triggered by Naegleria fowleri, has set off alarm bells for health authorities and the public alike.

While rare, PAM is among the most lethal infections known, with a global mortality rate of around 97 per cent. In Kerala, however, health officials note that the mortality rate so far is 24 per cent, considerably lower than international figures.

So, what exactly is this infection, why is it so deadly, and what can be done to prevent it?

What is Primary Amoebic Meningoencephalitis (PAM)?

PAM is an acute, rare brain infection caused by Naegleria fowleri, popularly known as the “brain-eating amoeba”. The organism is a free-living amoeba that thrives in warm freshwater bodies and soil. It is often found in lakes, ponds, rivers, hot springs, poorly maintained swimming pools, splash pads, and even in untreated water storage tanks.

Contrary to common fears, people cannot get infected by drinking contaminated water. The amoeba only infects humans when it enters the body through the nose — typically while swimming, diving, or when water forcefully enters nasal passages. From there, it travels to the brain, where it causes inflammation and destruction of brain tissue.

The U.S. Centers for Disease Control and Prevention (CDC) classifies it as one of the most aggressive and fatal infections, often striking otherwise healthy children, teenagers, and young adults.

Why is it called the ‘brain-eating amoeba’?

The term comes from the way Naegleria fowleri attacks the brain. Once inside, the amoeba consumes brain tissue, causing severe swelling (cerebral edema). This rapidly leads to neurological deterioration, coma, and, in most cases, death.

The infection progresses so quickly that by the time it is diagnosed, doctors often find themselves with very limited treatment options.

Symptoms of PAM

The symptoms typically appear five days after exposure, though they can occur as early as one day or as late as two weeks. Early symptoms mimic meningitis and include:

• Severe headache
• High fever
• Nausea and vomitingAs the disease advances, neurological symptoms develop, such as:

• Stiff neck
• Confusion and disorientation
• Loss of balance
• Seizures
• Hallucinations
• ComaAccording to Kerala health officials, most patients present late, by which time brain swelling is already extensive and treatment becomes far less effective.

Can it be treated?

There is no standard treatment for PAM. Globally, doctors have experimented with a combination of antimicrobial drugs such as amphotericin B, rifampin, azithromycin, fluconazole, dexamethasone, and the newer drug miltefosine.

Even with aggressive treatment, survival remains extremely rare. The CDC notes that most patients die within one to 18 days after the onset of symptoms, usually slipping into coma around the fifth day.

Notably, nearly all survivors over the past six decades were diagnosed before the infection spread extensively to the brain. This highlights the importance of early detection and immediate treatment.

Kerala’s situation

Kerala Health Minister Veena George has confirmed that this year’s cases are sporadic and scattered across districts, unlike last year when clusters were linked to specific water sources. This has complicated epidemiological investigations.

The infections have affected individuals ranging in age from three months to 91 years, with a higher number of male patients (33) compared to female patients (19).

Health authorities have launched environmental sampling of water sources, while the National Centre for Disease Control (NCDC) is assisting in investigations. Hospitals have been placed on alert, and public awareness campaigns are warning citizens to avoid swimming in untreated or stagnant freshwater bodies.

Why Kerala?

Cases of amoebic meningoencephalitis have been recorded in Kerala since 2016. Experts suggest that the state’s warm, humid climate and abundant freshwater bodies provide an ideal environment for Naegleria fowleri. With rising temperatures, such pathogens may become more common in tropical and subtropical regions.

However, health officials stress that while the disease is deadly, it remains extremely rare relative to other infections. The focus, therefore, is on prevention and vigilance.

How to stay safe?

• Avoid swimming or diving in stagnant freshwater during hot weather.
• Use nose clips or avoid getting water up the nose while swimming.
• Ensure proper chlorination of swimming pools.
• Do not use untreated water for nasal cleansing.

The rise in PAM cases in Kerala is a public health concern but also a reminder of the lurking risks in untreated water sources. With no reliable cure available, prevention and early diagnosis remain the only effective strategies.

As Kerala ramps up awareness campaigns, health authorities are urging citizens to stay cautious, particularly when engaging in water-based activities. While the infection is rare, its high fatality rate makes it one of the most feared waterborne diseases worldwide.