Amoebic meningoencephalitis: Fresh strains detected in Kerala; found in free-flowing water, dust

Thiruvananthapuram: The spread of amoebic meningoencephalitis, a brain infection caused by the brain-eating amoeba, is no longer linked to a single strain in Kerala.

Until recently, infections in the state were attributed only to Naegleria fowleri. But the Health Department has now confirmed that recent cases were also triggered by Balamuthia mandrillaris, Acanthamoeba and Vermamoeba vermiformis.

According to Dr K J Reena, Director of the Health Department, there is no immediate cause for alarm since medicines used against Naegleria fowleri are also effective against the other strains. “The state has adequate stock of this medicine,” she told Malayala Manorama.

What troubles experts, however, is the wider spread of these amoebae. Once confined to stagnant or polluted water, they are now being detected in free-flowing water, soil, and even airborne dust. Sudden weather shifts, such as short rain spells followed by intense heat, are believed to aid their growth.

Despite this, the expert committees set up by the Health Department are yet to submit findings, and a coordinated response involving the health, irrigation and local self-government departments has not begun, even though the outbreak has intensified since last year.

Since the first case in Kerala in 2016, the disease carried a grim 100 percent fatality rate until 2023. Last year, with earlier detection and availability of medicines, the fatality rate dropped to 25 percent.

Cases no longer seasonal
While stagnant water was once considered the main source of infection, data from 2024 and 2025 suggests otherwise. Cases were reported across almost all months, peaking in October 2024 with 10 infections, followed by August with 8. July and September each saw 5 cases, November 4, June 2, and May and December 1 case each.

Questions over official data
Adding to concerns is the lack of clarity in official statistics. Several cases initially confirmed as amoebic meningoencephalitis were later reclassified as “suspected cases”, allegedly to lower the official death rate.

For example, a Health Department report on May 14 this year noted 8 cases and 2 deaths. But in the revised figures released after July 5, the tally was altered to 7 cases and 1 death, raising doubts over the accuracy of the data.