Brain-Eating Amoeba

Brain-Eating Amoeba

Why in News? 

Kerala has recently confirmed the fifth fatality within a month from a rare brain disease called Primary Amoebic Meningoencephalitis (PAM). The infection is caused by Brain-Eating Amoeba and this type of infection is extremely dangerous and difficult to treat.

Infection caused by Brain-Eating Amoeba

• About: The brain-eating amoeba is the common name for a microscopic organism called Naegleria Fowleri. 

• Naegleria fowleri is a microscopic amoeba that survives independently in warm freshwater sources. It is invisible to the naked eye and can only be seen under a microscope.

• Scientists first identified this amoeba in 1965 in Australia, and since then, it has been reported in several parts of the world including the United States, Pakistan, India, and other tropical countries. 

• It grows best in temperatures between 25°C and 40°C, which makes hot springs, lakes, and poorly treated swimming pools ideal habitats.

• Unlike bacteria and viruses, this amoeba does not need a host to survive. It can live freely in the environment.

• Medium to Spread: The amoeba does not spread from person to person. Instead, it usually enters when people swim or dive in warm freshwater and contaminated water goes up the nose. From there, it attaches to the mucous membranes and travels along the olfactory nerve to reach the brain.

• It cannot cause infection if water is swallowed because the acidic environment of the stomach kills it.  

• Symptoms: The initial symptoms appear between one to nine days after exposure. These may look similar to common infections like viral meningitis, which makes early diagnosis difficult. The first signs include: Severe headache, Fever, Nausea and vomiting, Stiffness in the neck.

• • 1. As the infection progresses, more severe neurological symptoms appear such as: Confusion and disorientation, Seizures, Hallucinations, Loss of balance, Sensitivity to light, Rapid onset of coma.

• Impact: Once inside the brain, Naegleria fowleri causes a disease known as Primary Amebic Meningoencephalitis (PAM). The amoeba multiplies rapidly and begins to destroy brain tissue. Inside the brain, it produces harmful chemicals and enzymes that trigger intense swelling and inflammation of tissues.

• The destruction is fast and progressive. The infection leads to disruption of brain function, bleeding, and cell death. 

• In almost every known case, this results in coma and death within days. 

• Medical experts often describe the process as the amoeba “eating” the brain.

• Survival Rate: The fatality rate of Primary Amebic Meningoencephalitis is extremely high. More than 97 percent of recorded cases worldwide have ended in death.

• According to global data, out of over 430 reported infections, only a handful of patients survived.

• The disease usually progresses so quickly that death occurs within five to twelve days after symptoms begin. 

• 1. Many patients reach hospitals only after severe neurological signs appear, at that point, brain damage is already severe.

Where is Brain-Eating Amoeba Found?

• Global Distribution: The amoeba is found worldwide, mostly in regions with hot or tropical climates. Countries like the United States, India, Pakistan, Australia, and parts of Africa have reported cases. In colder countries, the risk is very low because the organism cannot live in cold water.

• Natural Sources: The amoeba grows best in warm freshwater lakes, rivers, ponds, and hot springs. It is also found in mud or soil near these water bodies. Stagnant water is more dangerous because it allows the amoeba to multiply. 

• 1. In some places, the amoeba has been detected in domestic water supplies. This usually happens when the water source is untreated or when pipelines are contaminated with organic material. 
  2. Consuming polluted water is not a risk since stomach acids break down and kill the amoeba before it can cause harm. 

Diagnosis and Treatment of this Infection 

• Diagnose: Doctors usually suspect this infection when patients show severe brain symptoms after recent contact with freshwater. 

• Doctors usually confirm the infection by examining cerebrospinal fluid (CSF) obtained through a spinal tap procedure. Under a microscope, experts may see the amoeba moving in the fluid. 

• Special staining techniques also help in recognizing its structure. Advanced laboratories use Polymerase Chain Reaction (PCR) tests, which can detect the genetic material of the amoeba more accurately and in less time.

• Imaging scans such as CT scans or MRI can show swelling of the brain, but they cannot confirm the presence of Naegleria fowleri. 

• Treatment: There is no single medicine that can cure the infection completely. Doctors usually use a combination of drugs in an attempt to stop the amoeba.

• The most common drug is Amphotericin B, which can kill the organism but also has serious side effects. 

• Other medicines include Azithromycin, Fluconazole, Rifampin, and Miltefosine.

• Miltefosine has demonstrated encouraging effects in laboratory and clinical use.

• 1. Some patients are placed in induced hypothermia, which lowers body temperature and slows the spread of infection. 

Since treatment options are limited, prevention is the best defense against Naegleria fowleri.