‘Brain-eating amoeba’ claims another life

KARACHI, Oct 3: The death of a young man caused by waterborne Naegleria meningitis has heightened concerns about the quality of water people consume in the city.
A staffer at the infection control section of the Liaquat National Hospital on Wednesday said that a 24-year-old man brought to the LNH with complaints of high-grade fever, headache, vomiting and drowsiness had died of Naegleria fowleri on Tuesday.
Despite efforts by senior physicians, the patient died after two days of his admission to the hospital, the said, adding that he had learnt that the Naegleria causing primary amoebic meningitis (PAM) in humans was a disease which had a fatality rate of over 99 per cent.
Since May, seven people, manly young men, have died of Naegleria fowleri or PAM in the city.
Health expert Dr Shazia says that “Naegleria fowleri is an amoeba that lives in fresh water and soil.”
“N. fowleri is a water-borne disease. Exposure occurs when people come into contact with warm, fresh water usually through swimming, diving, water skiing, or other recreational activity.” She said “The organism goes through three stages in its life cycle: cysts, flagellates, and trophozoites. It is the trophozoite form that causes human disease.” She added while talking to TheNewsTribe.
The danger of serious infection comes when water containing Naegleria fowleri is forced in into the nose and nasal mucosa. The parasite then migrates through the olfactory nerves and enters the brain.
Naegleria are “thermophilic,” meaning that they prefer warmer water. However, the cysts are able to survive for months in very cold water. Thus, Naegleria infection is found both in tropical and temperate climates.

Here are some Naegleria fowleri infection facts
Naegleria fowleri is an amoeba that lives predominately in warm, fresh water.
Naegleria fowleri is acquired by people when infected water is forcibly aspirated into the nose. This can occur through recreational swimming, diving, or during sports like water skiing.
Once acquired, the amoeba travels into the brain, causing primary amoebic meningoencephalitis (PAM).
PAM is very rare, and there are only a few cases reported each year in the United States.
People with PAM initially experience changes in smell or taste. The disease advances rapidly, causing fever, stiff neck, and coma.
Infection is diagnosed by examining spinal fluid under the microscope to identify the amoeba. Naegleria fowleri may also be grown in the laboratory, although this takes several days. Newer tests based on PCR technology are being developed.
The treatment of choice is an intravenous drug called amphotericin B. Amphotericin B may also be instilled directly into the brain.
More than 95% of cases of PAM are fatal despite treatment.

Symptoms and signs of a Naegleria fowleri infection
After entering the nose, the amoeba travels into the brain along the olfactory nerve and through membranes to enter the brain. Once there, it causes primary amoebic meningoencephalitis (meaning inflammation of the brain and the lining around the brain). In the popular press, Naegleria fowleri is sometimes called the brain-eating amoeba, and meningoencephalitis is sometimes referred to as Naegleriasis.
Symptoms usually appear within five days after exposure but can be delayed up to two weeks. Patients may initially notice changes in smell or taste. Fever, headache, loss of appetite, and nausea follow quickly. The patient becomes confused or semiconscious and finally comatose. Physical examination shows fever and a stiff neck (meningismus).

How is a Naegleria fowleri infection diagnosed?
A spinal tap will be done to examine the spinal fluid. Infection is diagnosed by seeing the amoeba under the microscope. Traditional Gram staining is not used to detect Naegleria because the heat used in the fixation process destroys the organism. Although not specific to Naegleria, the spinal fluid often has a mild elevation in the levels of proteins and a mild decrease in glucose, along with a high white cell count, and is often bloody in the later stages of disease.
Because rapid diagnosis is critical, examination of the spinal fluid is imperative. The organism can also be cultured in the laboratory using on a plate that is coated with bacteria for the amoeba to eat. The culture takes a few days. Newer tests are becoming available that use polymerase chain reaction (PCR) technology to detect amoebic DNA in spinal fluid.

How Naegleria fowleri infections be prevented?
Infection with Naegleria fowleri can be prevented by avoiding aspiration of fresh water into the nose. Although there have been investigations of how to reduce the risk of disease, it is not possible to eliminate the amoeba from all freshwater sources. Standard chlorination of swimming pools is sufficient to eliminate the organism. Untreated well water should not be forced into the nose or used to irrigate the nose.
Before current spread in Pakistan, Naegleria appeared in 1965 in Australia. 144 patient died till the date in the USA and UK.