The primary joint field-level research by the Keralam Well being Division and specialists from ICMR’s Nationwide Institute of Epidemiology in Chennai to explain the epidemiology of amoebic meningoencephalitis (AME) circumstances reported in Kerala in 2025 has recognized publicity to pure water our bodies and using non-chlorinated water for bathing and different home functions as important danger elements, offering the primary epidemiological proof from the State on probably modifiable exposures linked to amoebic meningoencephalitis.
The case-control research is the primary scientific proof of the questionable high quality of nicely water in Keralam, on which a major part of the inhabitants relies upon for bathing and different home use.
It has already been nicely defined by the scientific neighborhood that sure dangerous behaviours — publicity to pure water our bodies (particularly diving into water and snorting water into the nostrils), a historical past of earlier facial or nasal damage, and coming into pure water our bodies when there are ulcers or pores and skin wounds — predispose one to AME brought on by Acanthamoeba, which may enter the physique by way of tissue or the respiratory tract.
“The discovering that using non-chlorinated water, or nicely water, for home functions is independently related to AME brought on by Acanthamoeba is kind of related for Kerala, the place solely a tiny fraction of the inhabitants has entry to chlorinated, secure, piped water provide. Our research outcomes confirmed that folks utilizing nicely water for bathing or washing their face had 2.95 instances larger odds of getting AME,” factors out R. Aravind, Head of Infectious Illnesses, Thiruvananthapuram Authorities Medical School, and one of many key researchers concerned within the research.
“The estimated inhabitants attributable fraction (PAF) was 34.2%. Because of this 34.2% of the circumstances of AME brought on by Acanthamoeba within the inhabitants wouldn’t happen if non-chlorinated nicely water, as a particular danger issue, was eliminated,” Dr. Aravind identified.
(PAF is an epidemiological measure that estimates the proportion of illness circumstances in a inhabitants that will not happen if a particular danger issue have been eliminated.)
It must be famous that home water use referred to actions involving direct contact with the face, head, pores and skin, or physique, similar to bathing or washing the face or hair, and didn’t confer with ingestion.
Many households in Kerala rely upon particular person or public wells. Heavy rainfall, flooding, sewage contamination, natural matter, and algal progress would possibly contribute to the contamination of, or proliferation of free-living amoebae (FLAs) in, poorly maintained wells.
This case-control research is the very best stage of scientific proof that water high quality goes to be a key public well being difficulty by which the State must spend money on the instant future. Water high quality surveillance, together with periodic chlorination and upkeep of wells, needs to be a year-round exercise by way of native self-governments in order that the danger of individuals contracting AME will be minimised.
In a State the place there are numerous water our bodies, the main target of public well being messaging about AME must be on lowering high-risk exposures, significantly throughout the monsoon and post-monsoon interval, together with routine chlorination of home water sources.
The research, “Epidemiology of and Danger Elements for Amoebic Meningoencephalitis, Kerala 2025”, revealed within the newest difficulty of Rising Infectious Illnesses, the journal of the US Facilities for Illness Management and Prevention, analysed 159 AME circumstances reported in Kerala between January 1 and November 11, 2025. Of those, 76 have been confirmed by real-time PCR and 83 by microscopic examination of cerebrospinal fluid.
Among the many PCR-confirmed circumstances, 67 (88.2%) have been brought on by Acanthamoeba species and 9 (11.8%) by Naegleria fowleri.
That is important as a result of widespread notion, and even worldwide media consideration, centred on the “epidemic” of “brain-eating amoeba” (N. fowleri) infections in Kerala, when, in truth, an amazing majority of AME circumstances within the State in 2025 have been granulomatous amoebic encephalitis brought on by Acanthamoeba.
Among the many 159 case-patients, 41 died, giving a case fatality price of 25.8%. Seventeen of the 67 sufferers with PCR-confirmed Acanthamoeba an infection died (25.4%), whereas 4 of the 9 N. fowleri sufferers died (44.4%).
The researchers famous that between 2016 and 2024, Kerala had reported solely 45 AME circumstances and 15 deaths. Elevated scientific consciousness, wider availability of molecular diagnostics, and improved surveillance might have contributed to the sharp enhance in laboratory-confirmed AME circumstances in 2025.
To establish potential danger elements, the researchers carried out a matched case-control research restricted to 43 PCR-confirmed Acanthamoeba sufferers and 129 apparently wholesome controls from Thiruvananthapuram, Kollam, Kozhikode, and Malappuram. Three controls have been chosen for every case and matched for age, intercourse, and place of residence.
Publicity to pure water our bodies — swimming or diving in ponds and canals throughout the previous three months, particularly amongst individuals with a historical past of maxillofacial damage or nasal surgical procedure — was related to 4.7 instances larger odds of illness.
Exposing pores and skin wounds or ulcers to pure water our bodies had one of many strongest associations with AME. The percentages of AME on this group have been 25.4 instances larger. That is per the identified capacity of Acanthamoeba to enter by way of breaks within the pores and skin and subsequently disseminate to the central nervous system.
Public well being communication ought to due to this fact particularly advise individuals with earlier facial or head accidents, and people with wounds or pores and skin ulcers, towards coming into pure water our bodies, particularly throughout the monsoon and post-monsoon season.
The researchers make an essential distinction: whereas the entry of contaminated water by way of the nostril is a longtime route of transmission for N. fowleri, it has not been established as a route of transmission for AME brought on by Acanthamoeba.
Though Acanthamoeba AME has historically been related to immunocompromised people, within the Kerala research, most PCR-confirmed Acanthamoeba AME circumstances didn’t have documented immunocompromising circumstances, based on data.
The researchers say that host susceptibility stays essential, but it surely can’t by itself clarify the sample of AME seen in Kerala.
In addition they make a transparent distinction that the associations between Acanthamoeba AME and publicity to pure water our bodies or non-chlorinated water are epidemiological associations and don’t show that water publicity led on to neuroinvasion. Additional environmental, scientific, and microbiological research can be wanted to find out whether or not these associations mirror a route by way of which the illness was acquired.
Decrease socioeconomic standing was related to AME on this research, which could affect the behavioural exposures recognized by the researchers. Low socioeconomic standing might have an effect on entry to secure home water and enhance reliance on non-chlorinated wells. That is additionally why most AME circumstances are reported by public hospitals.
Danger communication on AME ought to due to this fact prioritise socioeconomically weak communities, the research notes.
