A parasite is any living organism that obtains nutrients necessary for its survival from other organisms, known as hosts. Most parasites cause significant neurological, cognitive, and mental health disorders in people by invading the central nervous system, including the brain. Upon entering the brain, these parasites release substances that disturb the host’s neural circuit. The parasite Naegleria fowleri is a tiny yet formidable creature under debate and has been the center of attraction for researchers.
What is a Naegleria fowleri?
Naegleria is a microscopic, free-living amoeba commonly inhabiting soil and freshwater bodies such as lakes, rivers, and hot springs. It can also be found in the host, specifically the central nervous system. The bacterium is thermophilic, meaning it thrives in warm temperatures and prefers warm water. It thrives at temperatures up to 115 degrees Fahrenheit (46 degrees Celsius), although it can tolerate even higher temperatures for a short time period. It has several species, but only Naegleria fowleri can cause human infections.
How Does Naegleria fowleri Infect the Human Body?
People become infected with Naegleria fowleri when water carrying the amoeba enters the body through the nose. This often occurs when individuals swim, dive, or submerge their heads in fresh water, such as lakes and rivers. Naegleria fowleri infections may also occur when people use contaminated tap water to clear their sinuses or wipe their nostrils during religious activities (sending water up the nose). People have infrequently contracted Naegleria fowleri infections from recreational water that lacked sufficient chlorine, such as pools, splash pads, and surf parks. The amoeba then goes up the nose to the brain, where it kills brain tissue and causes the lethal disease called primary amoebic meningoencephalitis, a deadly infection (PAM). Therefore, it is also referred to as a brain-eating amoeba.
Primary Amoebic Meningoencephalitis (PAM)
Primary amoebic meningoencephalitis, abbreviated as PAM, is a condition with potentially lethal outcomes, with a fatality rate of 98%. One of the most significant features of primary amoebic meningoencephalitis is inflammation in the brain, ultimately leading to swelling within the brain. Patients with weakened immune systems are more susceptible to becoming infected with this virus. PAM is a disorder that develops when an amoeba invades the layers that cover the brain, referred to as meninges.
Symptoms of Naegleria Fowleri Infections
PAM does not show any specific clinical signs. Symptoms start to show up within 24 hours of infection, although they can sometimes take between 5 and 7 days to appear. Patients experience severe symptoms at the start of infection, leading to death 18 days later.
High-grade fever, severe headache, vomiting, shivering, stiff neck, seizures, and photophobia are the symptoms that will eventually lead to coma and, ultimately, death.
Diagnosis of Naegleria Fowleri Infections
Serologic Testing
The measurement of antibody titers in infected patient sera against Naegleria fowleri is accomplished by using an indirect immunofluorescent antibody (IFA). On the other hand, this information is not particularly relevant given that most individuals with PAM pass away before an immune response can be generated.
Polymerase Chain Reaction (PCR) Testing
To identify if the ameba Naegleria fowleri is present, its DNA can be amplified from cerebrospinal fluid (CSF) or tissue using specific molecular techniques. The amplification of DNA from cerebrospinal fluid and fresh tissue samples is successful. More and more PCR-based methodologies, such as conventional and real-time PCR, have been reported for detecting and identifying free-living amebic infections in clinical specimens; however, these methods are currently only accessible at a few number of specialized reference diagnostic laboratories. For qualitative testing of Naegleria fowleri in clinical samples, the Centers for Disease Control and Prevention (CDC) also created a real-time PCR approach. Next-generation sequencing is a modern technique that is used for the detection of amoeba.
Lumbar Puncture
A lumbar puncture, often called a spinal tap, is a medical test to diagnose specific CNS-related medical conditions. This test involves cerebrospinal fluid or CSF extraction from the spinal canal by inserting a thin, long needle into the intervertebral space in the lumbar area. This fluid surrounds the brain and the spinal cord and protects them from injury by providing cushioning. Your health care provider may recommend lumber puncture or spinal tap if you have symptoms like hallucinations, vomiting, headache, and lower back pain. This test is commonly used to detect the presence of Naegleria fowleri in the CSF. Similarly, patients who undergo lumbar puncture may experience headaches or pain in the lower spine.
Biopsy
In this diagnostic procedure, tissues, cells, or fluids from the infected area of the body are removed for microscopic detection of amoeba.
Treatment of Naegleria Fowleri Infections
Medicines such as amphotericin B have amoebicidal characteristics and are strongly recommended for primary amoebic meningoencephalitis. At the same time, rifampin and miltefosine are also the drugs of choice. An antifungal agent, fluconazole, is also given in combination with amphotericin B in some cases of Naegleria fowleri infections. Besides treatment with medicines, keeping the body at a temperature below normal can reduce brain swelling. However, early diagnosis and treating the patient with advised drugs can save the patient’s life.
Preventive Measures For Naegleria Fowleri Infections
- Do not swim in water suspected to have Naegleria fowleri or water that is unclean and still for longer.
- Always use nose plugs whenever going inside water.
- Do not use water straight from the tape to clean your nose or mouth. Use distilled or sterilized water or at least boiled water for this purpose.
- Always use filtered water. Filters labeled NSF 53 or NSF 58 can be used for water filtration.
- Disinfecting the water is very crucial to prevent the infection. Always use chlorine or bleach to disinfect water used for nasal cleaning.
Final Thoughts
Naegleria fowleri, the brain eating amoeba was first identified in 1960. This amoeba prefers warm fresh water for its living and feeds on bacteria. However, it can also survive inside humans by feeding on neurons; when it finds entry through nose or mouth. Loss of attention, balance, neck stiffness are the symptoms associated with naegleria infection. The fatality rate is higher than 95% even after treating patients with amphotericin B and miltefosin.
About the Author
Dr. Madilyn Adams is a PhD in molecular medicine from Harvard University and has been working as a medical blogger for seven years.
References
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8469197/
- https://my.clevelandclinic.org/health/diseases/24485-brain-eating-amoeba
- https://www.cdc.gov/parasites/naegleria/general.html#
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4604384/
- https://www.sciencedirect.com/topics/medicine-and-dentistry/primary-amebic-meningoencephalitis#:~:text=Primary%20amebic%20meningoencephalitis%20(PAM)%20is,of%20parasites%20in%20biopsy%20samples.
