Brain Eating Amoeba: Symptoms, Causes, and Prevention

Q: What is the brain eating amoeba?

It’s a microscopic organism ( Naegleria fowleri ) that can cause a severe brain infection when introduced through the nose.

Brain Eating Amoeba Symptoms, Causes, and Prevention

September 17, 2025
Abrol Hospital

What is Brain Eating Amoeba?

The brain eating amoeba, or Naegleria fowleri, is a microscopic organism that primarily lives in warm, fresh water environments like lakes, rivers, and hot springs. It’s a free-living amoeba, meaning it exists naturally in these habitats and is not typically harmful to humans—unless certain conditions align.

When the amoeba enters the human body, typically through the nose, it travels to the brain and causes a rare, but devastating, infection known as primary amoebic meningoencephalitis (PAM). This disease progresses rapidly and can lead to brain damage and death.

How Does Brain Eating Amoeba Infect Humans?

The infection occurs when water containing Naegleria fowleri is introduced into the nose, often during activities like swimming, diving, or water sports in warm, stagnant freshwater. The amoeba uses the nasal passages to reach the brain, where it causes inflammation and destroys brain tissue.

While the infection isn’t spread through drinking contaminated water, the amoeba can enter the body when water enters the nose, especially if it’s forced up during activities like diving or water sports.

Symptoms of Brain Eating Amoeba Infection

The early symptoms of a brain eating amoeba infection usually start within 1-9 days after exposure to the contaminated water. These symptoms are often flu-like, making early diagnosis challenging. Some common symptoms include:

Headaches
Fever
Psychosomatic Disorder
Nausea and vomiting

As the infection progresses, the symptoms become much more severe, including:

Stiff neck
Seizures
Confusion or hallucinations
Loss of balance and coordination
Coma

The infection often leads to death within about 5 days of symptom onset, due to the rapid destruction of brain tissue. However, survival is extremely rare, and there is no guaranteed cure once the infection progresses to a critical stage.

What Are the Causes of Brain Eating Amoeba Infection?

The main cause of brain eating amoeba infection is exposure to warm, stagnant freshwater. This includes:

Lakes and rivers
Hot springs and geothermal areas
Swimming pools that are improperly maintained
Water-related activities in warm environments

Increased water temperatures and low water flow rates can promote the growth of Naegleria fowleri, which is why the infection is more commonly seen in hotter climates or during the summer months.

How to Prevent Brain Eating Amoeba Infection?

While it’s impossible to completely eliminate the risk, there are several ways you can reduce your chances of contracting a brain eating amoeba infection:

Avoid water entering the nose: If you’re swimming in warm, freshwater, avoid getting water up your nose. This can be done by keeping your head above water or using nose plugs.
Stay out of warm, stagnant water: The amoeba thrives in hot and stagnant water, so it’s best to avoid swimming in lakes or rivers during peak heat months.
Keep pools properly chlorinated: Chlorine in pools helps kill most harmful organisms, including the brain eating amoeba. Proper pool maintenance is crucial.

Conclusion

While the brain eating amoeba is rare, it is a serious and potentially deadly infection. Understanding its causes, symptoms, and preventative measures can help protect you and your loved ones. By taking simple precautions, like avoiding water entry into the nose during swimming activities and staying away from warm, stagnant freshwater, you can greatly reduce your risk.
Meet our Neurologists, Infectious Disease Specialists, and Emergency Care Team who are experienced in handling rare infections like brain eating amoeba.