Waking up to the Naegleria threat: urgent measures needed to protect public health in Pakistan

KEYWORDS:

• Naegleria fowleri
• pakistan
• public health
• naegleria outbreak
• PAM

Naegleria fowleri is a type of amoeba that thrives in high temperatures, up to 46°C (115°F) and can withstand even higher temperatures for short periods. It is known to cause a condition called Primary Amoebic Meningoencephalitis (PAM), which affects the CNS. The infection destroys brain tissue, causing brain swelling. Once symptoms appear, the disease rapidly advances and usually results in death within a span of 1 to 18 days. Some individuals possess specific antibodies against the amoeba, indicating prior infection and successful recovery. Although, the mortality rate associated with PAM is exceptionally high, at 97%, with only four known survivors out of 157 infected individuals in the United States between 1962 and 2022. Archived autopsy tissue samples have provided evidence of PAM infections in Virginia dating back to 1937. From 1961 to 1965, three documented cases of PAM were reported in Florida, Australia, and U.S.A. Since 1965, there have been approximately 300 reported cases of PAM worldwide in the past 50 years. Out of these, 132 cases were from the U.S.A., 19 from Australia, 17 from Pakistan, 16 from the Czech Republic, 11 from India, 9 from Mexico, 9 from New Zealand, 7 from Venezuela, 5 each from Thailand and Belgium, 4 from Nigeria, 2 from the UK, and 1 case each from Namibia, Iran, Costa Rica, New Guinea, South Africa, and Madagascar. Only 11 out of the 260 documented cases were reported to have survived. The majority of these cases have affected young males [1–5].

N. fowleri has emerged as a significant public health concern in Pakistan, particularly in the coastal regions. The majority of cases of PAM are reported during the summer and pre-monsoon period. Ongoing scientific investigations are focused on understanding the presence and distribution of N. fowleri in Pakistan’s water bodies and exploring any potential correlation with climate change. It is noteworthy that all reported cases of PAM in Pakistan have been documented in individuals adhering to the Muslim faith, with only a few cases having a history of recreational water activities. This suggests a potential presence of N. fowleri in domestic water supplies in Karachi. Despite the typically saline nature of Karachi’s water, the infections often occur during ablution, indicating that the local strain of N. fowleri may have developed resistance to saline environments or possess unique characteristics compared to strains found elsewhere [6]. Pakistan exhibited the second highest prevalence of Naegleria infections globally. In 2023, Naegleria caused the loss of seven lives in Pakistan. Out of these 4 deaths were reported in Karachi, 1 in Hyderabad, 1 in Quetta, and 1 in Lahore. situation demands further attention, especially given that the first documented case of PAM in Pakistan was reported in 2008. It is worth noting that the number of reported PAM cases in Pakistan has surpassed the number of cases reported in the U.S.A. over the past 50 years, with 142 cases reported between 1968 and 2019. As of October 2019, Karachi alone had reported 146 cases. The age distribution of PAM cases in Pakistan also differs from that in the U.S.A., as it predominantly affects adults aged 26–45 years, whereas in the U.S.A., it primarily impacts children under 14 years of age. This discrepancy suggests the possible presence of a distinct strain in Pakistan [7]. Furthermore, health authorities in Lahore have recently reported the first case of PAM in 2023, in which a 30-year-old patient was admitted to Services Hospital. Similarly, health officials in Karachi have reported an infection and subsequent fatality caused by N. fowleri this year [8].

In cases where PAM is suspected, a healthcare practitioner may recommend a cerebrospinal fluid examination through spinal tap or a brain biopsy to confirm the presence of the organism. To diagnose a N. fowleri infection, the examination of fresh CSF by real-time PCR is necessary. The preferred treatment for PAM is the use of the antifungal drug amphotericin B. In certain cases, survivors in North America have received a combination of medications, including amphotericin B, rifampin, fluconazole, and miltefosine. Promising outcomes, demonstrated by complete recovery in two children, have been observed when PAM is diagnosed early and treated promptly with the recommended medications. Additional measures, such as cooling the body to below-normal temperature to address brain swelling, have also contributed to positive results. Unfortunately, the prognosis for individuals infected with N. fowleri is generally unfavorable, as even with treatment, most people do not survive this condition. Therefore, early detection and treatment of the infection play a critical role [2,3].

N. fowleri infection is not contagious but may become more common due to climate change. Heat waves can also create a favorable environment for the growth of amoeba. Rising water temperatures due to climate change could create more suitable environments for N. fowleri, increasing infection risks. In addition to water exposure, people can also become infected by inhaling cyst-contaminated dust, which then leads to infection as the cysts transform. While the trophozoite stage of N. fowleri is relatively sensitive to environmental changes, the cyst form is more resilient. Drying quickly renders trophozoites nonviable, whereas cysts become nonviable in less than 5 minutes [2].

The occurrence of N. fowleri in Pakistan is posing a substantial public health concern due to its high mortality rate and limited treatment options. To effectively mitigate N. fowleri infections, the government and health authorities should take action. This involves raising awareness among the population about the risks and importance of preventive measures, training healthcare professionals for early detection and treatment, and responding to infection emergencies. They also need to make sure drinking and utility water sources are tested for N. fowleri. It is important to keep swimming pools clean and properly chlorinated, and to handle warm water discharge from industrial plants safely. People should use clean containers for water storage. To protect themselves, people should avoid swimming in warm freshwater, especially stagnant water, and use nose plugs. For clinicians, it is crucial to quickly and accurately identify the causative agent in order to guide appropriate treatment decisions. It is worth noting that N. fowleri infection cannot be transmitted from one person to another. They should be careful when doing religious rituals that involve cleansing the nasal passages or rinsing the sinuses. Tap water shouldn’t be used for nasal irrigation; distilled or sterilized water is safer. If tap water is the only option, it should be boiled and then cooled. Filters labeled ‘NSF 53’ or ‘NSF 58,’ or with a pore size of 1 micron or smaller, can remove germs [2,3]. By taking these steps, we can work toward reducing the incidence of N. fowleri infections in Pakistan.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

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Funding

This paper was not funded.