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What Happens To Untreated Naegleria Infection?

Free-living amoebae such as Naegleria, Sappinia, Vermamoeba, Acanthamoeba, and Balamuthia are extremely fatal and pathogenic to individuals. Their cysts are very much resilient and resistant to adverse environments due to the progress of encystment. Even though the infection cases are exceptionally unusual, the identification of free-living amoebae must certainly not be disregarded or ignored because it may cause serious illness. At present, the facts of pathogenic free-living amoebae occurrence have increased and gained considerable attention worldwide because of its potential health implications.(1)

What Happens To Untreated Naegleria Infection?

What Happens To Untreated Naegleria Infection?

If primary amoebic meningoencephalitis (PAM) is untreated, it may lead to a high mortality rate of greater than 97%. High Fever with meningitis, dizziness, and headache; nausea sensation and tasteless feeling were observed in most cases of untreated infected individuals. Early symptoms include vague upper respiratory distress, difficulty in body, lethargy, and intermittently olfactory problems. The acute phase includes sore throat, stuffy blocked or discharging nose, and severe annoyance in the head.

Progressive symptoms include stiffness of the neck. Cerebral edema and brain swelling progress rapidly causing death. The incubation period of these free-living amoeba i.e., from the time of onset of symptoms to death, is 5 days. Due to the rarity of N. fowleri infections in humans, there are no clinical trials to date that assess the efficacy of one treatment regimen over another.(1)

Other Serious Complications

In many cases, cardiac rhythm abnormalities and myocardial necrosis have been observed. The most important pressure raises in the intracranial region i.e. in cerebral spinal fluid (CSF) space causing seizure associated with death. Magnetic resonance imaging (MRI) studies had revealed aberrations in several areas of the brain, including the midbrain and subarachnoid space. Positive Brudzinski sign, positive Kernig sign, photophobia, and confusion signs and symptoms indicate N. fowleri infection. Analysis of cerebrospinal fluid (CSF) usually reveals a high opening pressure, a predominantly neutrophilic pleocytosis, elevated protein concentration, and low glucose levels.(2)

Immune System Role in Infection

N. fowleri enters the human body in the trophozoite form. After invading the human systems, the immune response gets activated i.e., production of macrophages and neutrophils against pathogens. Tissue destruction by the food cup (a type of structure formed by amoeba) and the release of cytolytic enzymes occurs. Acid hydrolases, phospholipases, neuraminidases, and phospholipolytic enzymes that play a significant role in the infected cell causing nerve destruction.

Survivor Cases

Up to date, there have been only seven survivors worldwide. The patient who survived the pathogen infection has suffered severe brain damage. Intravenously and intrathecally injection of conventional amphotericin B, miconazole, oral rifampin, intravenous dexamethasone, oral phenytoin, fluconazole, azithromyci, and medically induced hypothermia were used in the treatment of that survivor.(2)

Southeast Asia – Sensitive To Infection

In Southeast Asia, the incidence rate of free-living amoebae particularly Naegleria spp were reported in Malaysia, Thailand, Vietnam, and the Philippines. Inadequate educations of free-living amoeba attributed to the lack of prevalence information across the Southeast Asian region. Among the sensitive regions, Thailand was reported most of the primary amoebic meningoencephalitis (PAM) particularly from Thai male individuals after exposure to polluted soil and aquatic environments.(1)


The last five years have shown that primary amoebic meningoencephalitis (PAM) remains a devastating central nervous system infection associated with warm freshwater exposure. The detection of this disease is time-consuming and cannot be diagnosed rapidly. Most people who have Naegleria infection die within a week if untreated. Even if treated, the rate of survival is very less. Up to date, there have been only seven survivors worldwide. And millions of individuals are exposed to the amoeba that causes Naegleria infection each year, but only a handful of them ever get sick from it.


Also Read:

Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:June 12, 2019

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