Nguyen Van Binh, head of the Ministry of Health's Preventive Medicine Department, spoke to the Vietnam News Agency about how a brain-eating amoeba causes meningoencephalitis
A 25-year-old man from central Phu Yen Province recently died from the effects of exposure to the brain-eating amoeba Naegleria fowleri, leading to significant public concern. What are the mechanisms causing primary amoebic meningoencephalitis, which has never before been seen in Viet Nam?
Primary amoebic meningoencephalitis is a rare but potentially fatal disease. The United States confirmed 123 cases between 1962 and 2011. In Viet Nam, the death of the 25-year-old man is believed to be the first-ever recorded case of the brain-eating amoeba Naegleria fowleri.
The amoeba lives predominately in warm bodies of freshwater such as lakes and rivers in tropical and subtropical climates. It grows best at a temperature of 46 degrees Celsius, but it has also been found to survive at higher temperatures of 50-56 degrees Celsius.
The amoeba infects people when water containing it enters the body through the nose and travels up to the brain, where it causes primary amoebic menigoencephalitis. It does not enter the body via the mouth. The Naegleria fowleri infection cannot be spread from one person to another.
Could you tell me harmful levels of the amoeba to human health? What is the risk of getting the Naegleria fowleri infection from a disinfected swimming pool, river or lake?
Only a few people have been infected compared to the millions of other people using similar water in the southern part of the USA. However, the fatality rate is very high because there is no drug to treat the disease.
But people should not worry when they go swimming in swimming pools or hot springs because almost all swimming pools and hot springs seriously obey regulations to disinfect water to prevent swimmers from infectious diseases.
How can we prevent the amoeba from harming the community?
The brain-eating amoeba has over 15,700 protein-coding genes in it. It grows in three forms: cyst, trophozoite and flagellate. As a trophozoite, it moves around to find bacteria it can feed on. The amoeba takes the form of a flagellate when it is looking for a better environment to live in. It encysts in severe weather conditions.
Water in ponds, lakes, and rivers provides favourable conditions for amoebic growth. Only as a form of trophozoite does it cause primary amoebic meningoencephalitis in humans. It cannot cause primary amoebic meningoencephalitis for a significant number of people.
People are advised to obey recommendations issued by the Ministry of Health to avoid exposure to the amoeba and its harmful effects.
So what are these recommendations?
The recommendations include holding your nose shut, using nose clips, or keeping your head above water when taking part in water-related activities in bodies of warm freshwater.
After bathing or swimming in swimming pools, ponds, lakes or rivers, clean your nose with antiseptic solution.
If you experience symptoms including headache, fever, or vomiting, go immediately to the nearest health clinic. — VNS