Naegleria Fowleri: The prevalence of a brain-eating amoeba in freshwater bodies in India

Dear Editor,

The recent rise in alarming reports of cases of Naegleria fowleri infections have caused severe distress in the medical world. In the past, there have been 20 cases of Naegleria Fowleri causing infection in India. There have been as many as 7 cases in the last 2 months in the state of Kerala when in the past there have been only around 500 cases reported of the same since 1965. These devastating brain infections endanger mostly children and adults under the age of 20 years. Out of the cases reported, there were 3 deaths in children of less than 5 years of age, adding to its devastating nature. Two Australians named Fowler and Carter reported the first case of Naegleria fowleri infection, commonly referred to as the “brain-eating amoeba” in 1965 [1]. Infection rates of the amoeba increase during summer months causing the disease, primary amebic meningoencephalitis (PAM).

Naegleria fowleri is a free‐living, thermophilic, pathogenic flagellate amoeba belonging to the Heterolobosea class. It feeds mostly on bacteria living in natural bodies of warm freshwater, which is where it has been frequently detected. This parasite is also known as amphibolic amoeba. Three morphological stages of the Naegleria species life cycle have been identified: trophozoite, pear‐shaped temporary flagellate stage and cyst stage. N. fowleri contains a sucker‐like surface structure called ‘food cup’ that enables this amoeba to digest brain tissue. It also releases different cytolytic molecules which cause further destruction of nerves [2].

Usually, sporadic infections occur in hot and humid areas and are frequently fatal. The general population are at risk of exposure to the organism via swimming, bathing, or other recreational activity during which water is forcefully inhaled into the upper nasal passages [2]. Despite increased interest in N. fowleri in recent years due to well-publicized cases linked to drinking water, many questions still remain unanswered [3], mainly those pertaining to the causes and risk factors predisposing an individual to exposure. Mortality is very high, mainly due to delayed diagnosis of the causative organism, overwhelming inflammation of the central nervous system, and lack of effective treatment. It is also a public health issue because of the rapid onset and high mortality of PAM.

Cases in India have been reported in various states, including but not limited to West Bengal, Andhra Pradesh, Telangana, Karnataka, Kerala and Tamil Nadu. These states have higher temperatures and are known for their freshwater bodies, which could contribute to the presence of Naegleria fowleri. The majority of cases in India have been reported during the hotter months [4]. This correlates with the increased temperature in freshwater bodies, which can facilitate the growth of Naegleria fowleri. Health authorities in India monitor cases of Naegleria fowleri and sometimes investigate outbreaks. Public health initiatives should focus on increasing awareness and educating people about the risks associated with contaminated water.

The first symptoms usually appear between 3 and 7 days, but not later than 14 days, after exposure. The onset of symptoms is immediate and severe. During the initial period of infection, PAM is characterized by severe nausea with vomiting, high fever, headache, and neck stiffness. The second phase is characterized by a pyogenic meningoencephalitis and coma eventually occurs. Death occurs one week after the onset of symptoms. N. fowleri causes a nearly always fatal disease (over a 95 % case fatality rate) [2].

Studies have shown that the entry and infiltration of the amoeba cells in the nose occurs with less inflammation. The lack of an inflammatory response upon entry into the nasal tissue with subsequent strong reactions in the brain indicates that the amoebae have a way to bypass the innate immune response and invade the tissue undetected [5]. As a result, diagnosis of this disease is often done too late to save the patient. Therefore, in terms of research, there is a vast potential to develop more effective diagnostic tools that can identify the causative organism at an earlier stage and more effective treatment modalities.

There is vital importance to incorporate various preventive measures in order to reduce risk of exposure. These include ensuring proper maintenance, i.e. timely chlorination, of swimming pools and hot tubs, avoiding taking baths in untreated freshwater bodies, using nose clips while in the water, keeping the head above water and keeping away from freshwater activities during the peak seasons. This also highlights the need to encourage public health efforts that focus on educating healthcare providers about early recognition and management protocols to improve patient outcomes. A regular surveillance is important from the local administrative bodies. Proper awareness program should be conducted. It is strongly advised not to swim in fresh waterbodies in summer time. Regular cleaning of the nose is crucial.

No vaccines are currently available against N. fowleri. It is also important to develop a vaccine. More research should be conducted on this. A collaborative approach is needed among microbiologists, infectious disease specialists, physicians, public health specialists, environmental scientists and geologists to effectively combat this rare yet fatal amebic infection.

The recent cases draw attention to the critical need for heightened awareness among healthcare providers and the public alike. Awareness campaigns and notices targeted at frequent recreational water users and providers of water-based activities must be conducted. By advocating for improved water management and hygiene practices, we can mitigate the transmission of N. fowleri in susceptible populations, i.e. children. Equally crucial is the availability of accurate information to negate misconceptions and ensure immediate seeking of medical care upon appearance of symptoms. In conclusion, while N. fowleri presents a difficult challenge, proactive measures based on scientific understanding and community involvement offer the best hope for reducing its impact and safeguarding public health.

Funding

No funding received.

Ethical approval

Not applicable.

CRediT authorship contribution statement

Vardhini Ganesh Iyer: Writing – original draft, Writing – review & editing. Novonil Deb: Writing – review & editing. Dattatreya Mukherjee: Writing – original draft. Sanjit Sah: Writing – review & editing. Aroop Mohanty: Data curation, Writing – review & editing. Vikash Jaiswal: Conceptualization, Writing – original draft, Writing – review & editing. Ranjit Sah: Writing – original draft, Writing – review & editing.

Declaration of competing interest

I hereby declare that there is no conflict of interest amongst any of the authors regarding the publication of this manuscript.

Handling Editor: Patricia Schlagenhauf