Naegleria fowleri is commonly known as ‘brain eating ameba’. It causes primary amebic meningoencephalitis (PAM). Although, it is rare with 132 reported cases from 1962-2013 in the United States, the infection is mostly fatal. N. fowleri is a free living ameba that is found in soil and water. It has 3 life stages, which include ameboid trophozoite, flagellate and cyst stages out of which only trophozoite stage is infectious. N. fowleri grows in temperatures between 25-420C; however, can also survive long periods of time in lower temperatures in its cyst stage. More than 30 species of Naegleria have been determined, but only N. fowleri is associated with infection in humans. (1)
Primary amebic meningoencephalitis carries high fatality rate that is approximately 98%, and results in death within 1-12 of infection. It is more common in children and young adults with a history of swimming in contaminated water. However, few cases of PAM infection in non-swimmers have been linked to the use of neti-pots for sinus irrigation or ritual nasal cleansing. N. fowleri infection is extracted when ameba contaminated water enters nasal cavity through which it travels to the brain resulting in PAM. (1)
Can You Get Brain Eating Ameba From Taking A Shower?
The first cases of N. fowleri implicated with drinking water in the United States was reported in Arizona (2002) in two 5 year old boys, who were exposed to the contaminated water via bathing in municipal tap water, which was sourced from inadequately disinfected groundwater wells. N. fowleri has been found in samples of household water from taps, showers, showerheads, water heaters and is also found in bathtubs, bathroom sink taps. (1)
Prevention and Control Of Naegleria Fowleri
A case control study was conducted to determine the quality of drinking water and N. fowleri presence. In the study, N. fowleri was positively associated with water temperature, maximum daily air temperature and colony count at 35oC. The ameba was negatively associated with presence of Acanthameba, presence of high temperature tolerant Naegleria species excluding N. fowleri and free chlorine residual. This emphasizes the importance of adequate disinfection of drinking water. Free chlorine residual level of 0.2-0.5 mg/l is the appropriate conservative method to target N. fowleri species. (1)
Since, Naegleria fowleri is naturally found in lakes and rivers, which unfortunately has no control over humans so prevention in these water bodies is difficult. Therefore, it should be assumed that these water bodies (freshwater lakes, rivers, hot springs) and recreational waters (swimming pools) are associated with low risk of infection. The only way to prevent N. fowleri infection is to stay away from swimming in warm freshwaters. Some personal measures can be taken while entering these water bodies to minimize the risk of infection and inhalation of water through nostrils. These include use of nose clips or keeping head above water, avoid submerging head under water in hot springs and other untreated thermal waters, avoiding water related activities in warm freshwater during summer months and avoiding digging or stirring up sediments when taking part in water related activities in warm freshwater bodies. (2)
Although, most of the reported N. fowleri infections are associated with swimming in fresh water lakes and rivers, there are few reported cases of deaths that have been associated with tap water and drinking water inhalation via nostrils. According to CDC, N. fowleri infection does not occur after drinking water contaminated with the ameba. The infection only occurs when contaminated water enters the nostrils. (2)
A press release published by St. John the Baptist Parish in Louisiana advised few precautions regarding tap water and drinking water activities. The recommendations include prevention of water inhalation via nose or sniffing water into nose while washing face, showering, bathing, or swimming in small hard plastic/blow up pools. In addition, jumping and submerging head under bathing water in bathtubs should be avoided along with supervising children when playing with hoses or sprinklers, as there is increased chances of inhalation of water via nose during these activities. (3)
Also Read:
- Brain Eating Amoeba or Naegleriasis: Symptoms, Treatment, Prevention
- Can You Get Brain Eating Amoeba From Tap Water?
- Can You Survive Brain Eating Amoeba?
- How Can You Protect Yourself From Brain Eating Amoeba?
- How Do You Know If You Have A Brain Eating Amoeba?
- What Temperatures Do Brain Eating Amoeba Live In?
