Naegleriasis (also known as primary amoebic meningoencephalitis; PAM) is an almost invariably fatal infection of the brain by the free-living unicellular eukaryote Naegleria fowleri. Symptoms are meningitis-like and include headache, fever, nausea, vomiting, a stiff neck, confusion, hallucinations and seizures. Symptoms progress rapidly over around five days, and death usually results within one to two weeks of symptoms.N. fowleri is typically found in warm bodies of fresh water, such as ponds, lakes, rivers and hot springs. It is also found in an amoeboid or temporary flagellate stage in soil, poorly maintained municipal water supplies, water heaters, near warm-water discharges of industrial plants and in poorly chlorinated or unchlorinated swimming pools. There is no evidence of it living in salt water. As the disease is rare, it is often not considered during diagnosis.Although infection occurs very rarely, it almost inevitably results in death. Of the 450 or so naegleriasis cases in the past 60 years, only seven have survived, for a case fatality rate of 98.5%. Signs and symptoms
Onset of symptoms begins one to nine days following exposure (with an average of five). Initial symptoms include changes in taste and smell, headache, fever, nausea, vomiting, back pain, and a stiff neck. Secondary symptoms are also meningitis-like including confusion, hallucinations, lack of attention, ataxia, cramp and seizures. After the start of symptoms, the disease progresses rapidly over three to seven days, with death usually occurring anywhere from seven to fourteen days later, although it can take longer.
In 2013, a man in Taiwan died 25 days after being infected by Naegleria fowleri.It affects healthy children or young adults who have recently been exposed to bodies of fresh water. Some people have presented with a clinical triad of edematous brain lesions, immune suppression and fever. Scientists speculate that lower age groups are at a higher risk of contracting the disease because adolescents have a more underdeveloped and porous cribriform plate, through which the amoeba travels to reach the brain. Cause
N. fowleri invades the central nervous system via the nose, specifically through the olfactory mucosa of the nasal tissues. This usually occurs as the result of the introduction of water that has been contaminated with N. fowleri into the nose during activities such as swimming, bathing or nasal irrigation.The amoeba follows the olfactory nerve fibers through the cribriform plate of the ethmoid bone into the skull. There, it migrates to the olfactory bulbs and subsequently other regions of the brain, where it feeds on the nerve tissue. The organism then begins to consume cells of the brain, piecemeal through trogocytosis, by means of an amoebostome, a unique actin-rich sucking apparatus extended from its cell surface. It then becomes pathogenic, causing primary amoebic meningoencephalitis (PAM or PAME).Primary amoebic meningoencephalitis presents symptoms similar to those of bacterial and viral meningitis. Upon abrupt disease onset, a plethora of problems arise. Endogenous cytokines, which release in response to pathogens, affect the hypothalamus thermoregulatory neurons and cause a rise in body temperature.