Systematic Review of Brain-Eating Amoeba: A Decade Update

Abstract

Introduction: Primary amoebic meningoencephalitis (PAM) is a rare but lethal infection of the brain caused by a eukaryote called Naegleria fowleri (N. fowleri). The aim of this review is to consolidate the recently published case reports of N. fowleri infection by describing its epidemiology and clinical features with the goal of ultimately disseminating this information to healthcare personnel. Methods: A comprehensive literature search was carried out using PubMed, Web of Science, Scopus, and OVID databases until 31 December 2022 by two independent reviewers. All studies from the year 2013 were extracted, and quality assessments were carried out meticulously prior to their inclusion in the final analysis. Results: A total of 21 studies were selected for qualitative analyses out of the 461 studies extracted. The cases were distributed globally, and 72.7% of the cases succumbed to mortality. The youngest case was an 11-day-old boy, while the eldest was a 75-year-old. Significant exposure to freshwater either from recreational activities or from a habit of irrigating the nostrils preceded onset. The symptoms at early presentation included fever, headache, and vomiting, while late sequalae showed neurological manifestation. An accurate diagnosis remains a challenge, as the symptoms mimic bacterial meningitis. Confirmatory tests include the direct visualisation of the amoeba or the use of the polymerase chain reaction method. Conclusions: N. fowleri infection is rare but leads to PAM. Its occurrence is worldwide with a significant risk of fatality. The suggested probable case definition based on the findings is the acute onset of fever, headache, and vomiting with meningeal symptoms following exposure to freshwater within the previous 14 days. Continuous health promotion and health education activities for the public can help to improve knowledge and awareness prior to engagement in freshwater activities.

Amebic encephalitis and meningoencephalitis: an update on epidemiology, diagnostic methods, and treatment

“…US cases were most often attributed to exposure in a lake, pond, or reservoir, whereas non-US cases commonly reported swimming pool and tap water exposure, which may reflect differences in regulations for monitoring or maintaining water quality between countries. The age and sex distribution of PAM patients is similar in the United States and other countries; most cases occur in adolescent male individuals [15,19]. However, the youngest patient known to have been infected with PAM was diagnosed recently in Turkey at only 11 days of life [20].…”

Noninvasive diagnostic biomarkers, genomic profiling, and advanced microscopic imaging in the early detection and characterization of Naegleria fowleri infections leading to primary amebic meningoencephalitis (PAM)

“…For instance, observing N. fowleri directly in a sample can be influenced by the operator’s skill and may be less effective with untrained personnel. Additionally, PCR techniques for analysis may be limited in specific centers, particularly in rural and district hospitals 4 . Hence, the key to diagnosis rests on clinical suspicion, and a definitive gold standard test for diagnosing N. fowleri has yet to be established.…”

“…Among the 47 recognized Naegleria species, N. fowleri is the sole causative agent of a fatal brain infection known as primary amoebic meningoencephalitis (PAM) 4 . While PAM is infrequent, it is a highly lethal human ailment, with a mortality rate ranging from 95 to 97% 5 .…”

Emergence of Naegleria fowleri Infection in Lahore: Expanding Geographical Range and Implications for Surveillance and Research

“…3 Based on Centers for Disease Control and Prevention (CDC) data spanning from 1962 to 2022, Naegleria infection has exhibited a mortality rate surpassing 97% with only four survivors out of 157 cases in the United States, 2 while a recent systematic review published in 2023 has underscored this severity, revealing a significant mortality rate of 72.7% for Naegleria infection globally. 4 N. fowleri cases have only been seen in Karachi, with the first one going all the way back to 2008. Up until October 2019, 146 cases had been recorded in Karachi.…”

“…By carefully examining unique genetic markers, novel genes, and horizontally transferred genes, we can gain insights into the mechanisms underlying this disease. 4 Knowing the underlying mechanism of the disease, proper diagnostic criteria and treatment protocols can be developed that can help bring down the current 97% fatality rate and hopefully solve the Naegleria problem that has plagued Pakistan.…”