Journal of Medical Science and Clinical Studies
Research Article Volume: 2 & Issue: 1
Abstract
Abstract: Brain infections are a major public health challenge in India as; there are an estimated 650,000 cases of encephalitis and 560,000 cases of meningitis annually nationally. Primary Causes of Meningitis include Streptococcus pneumoniae, Haemophilus influenzae type b (Hib), mostly in children and Neisseria meningitidis, Listeria monocytogenes and Tuberculous meningitis (TBM) contribute to vulnerable or older population’s infections. Viral encephalitis due to Japanese Encephalitis (JE) are the leading aetiologies, a serious mosquitoborne condition contributing up to 40% of paediatric cases, and Herpes simplex virus (HSV), Enteroviruses, Dengue, and Chikungunya are other viruses causing encephalitis. Parasitic meningoencephalitis in India primarily refers to rare but highly lethal Primary Amoebic Meningoencephalitis (PAM) caused by free-living amoebae (FLA) like Naegleria fowleri often called the “brain-eating amoeba.
The first ever case of amoebic meningoencephalitis in India was documented in 1971 in two children in Kolkata, West Bengal. For decades, cases were rarely diagnosed and often lumped into the broader, poorly defined category of Acute Encephalitis Syndrome (AES). Between 2024 and 2025, the state of Kerala experienced its largest-ever documented outbreaks of amoebic meningoencephalitis.
Materials and Methods: This review integrates current understanding of their biology, epidemiology, clinical features, diagnostics, and treatment strategies, learning from Kerala outbreaks in 2024–2025. Rising water temperatures, high-risk behaviours like swimming in untreated freshwater and nasal irrigation with non-sterile water contribute to pathogen proliferation. People’s practices of defecating and ablution near water sources leading to coliform contamination on one hand, and inadequate chlorination of most sources, increase exposure to contaminated water. Better diagnosis through PCR and metagenomic sequencing, have improved detection of infection and early Treatment, resulted in lower mortalities (24%) compared to the global rate of 90%.
Outcomes: The first reported case of PAM in 2024 was on May 21, involving a five-year-old girl. Official figures indicate a breakdown of the year-wise confirmed cases and reported fatalities 336 confirmed cases with 81 fatalities since the first case. Kerala has seen a surge in reported cases of amoebic meningoencephalitis due to stricter mandatory testing of all clinically suspected cases and statewide tracking. Given the fulminant course of Primary amoebic meningoencephalitis, aggressive empiric early therapy strategy on clinical suspicion without waiting for confirmation of diagnosis, with a combination of different classes of drugs, including amphotericin B and miltefosine, has been shown to improve survival.
Keywords: Primary Amoebic Meningoencephalitis (PAM), Amoebic liver abscess (ALA), Japanese Encephalitis (JE), Tubercular Meningitis (TBM), Naegleria fowleri, Acanthamoeba, CSF wet mount examination, Gram stain, Calcofluor stain, Giemsa stain, culture for bacteria as well as free-living amoebae & PCR testing, Amphotericin B, Nitroxoline, Public health alerts.