State public health lab develops molecular tests to identify deadly amoeba

The State Public Health Laboratory, one of the apex referral laboratories in the State, has developed its own molecular diagnostic test kits to identify five common species of free living amoeba (FLA) which are toxic to humans and which can cause amoebic meningoencephalitis. A highly fatal brain infection, cases of amoebic meningoencephalitis are being reported frequently in Kerala now.

“It was a proud moment for us when we identified Acanthamoeba spp. as the pathogenic organism in one of the acute encephalitis syndrome (AES) samples that we received from the Thiruvananthapuram Government Medical College on Thursday. It was also the first human sample in which we could identify the organism, after we developed the molecular diagnostic test kits six months ago,” says S. Sunija, Director of the State PH Lab.

Early identification of the pathogen and treatment are crucial for saving lives when it comes to amoebic meningoencephalitis. Now that the PH lab has developed its own molecular (PCR) assays for identifying the pathogenic organism in human samples, Kerala no longer needs to depend on prime diagnostic facilities outside the State, such as PGI Chandigarh, for confirmatory diagnosis of amoebic meningoencephalitis.

Over 400 species

Though there are over 400 species of free living amoeba in the environment, only six have been documented to be pathogenic to humans. The State PH lab is also the only lab which has the ability to identify five of these toxic organisms — Naegleria fowleri, Acanthamoeba spp., Vermamoeba vermiformis, Balamuthia mandrillaris and Paravahlkampfia francinae.

“Till now, through the microbiological examination of cerebrospinal fluid samples, we could make only a presumptive diagnosis that it was a trophozoite causing the encephalitis. Naegleria fowleri being the one that causes the most fatal disease, our protocol was to start the patient on the drug cocktail for N. fowleri immediately. But now that the pathogen can be identified and confirmed early, we can optimise the drugs and give targeted treatment to the patient without delay,” says R. Aravind, Head of Infectious Diseases, Government Medical College, Thiruvananthapuram.

To labs outside the State

Ever since the State began reporting cases of amoebic encephalitis, the lack of confirmatory diagnosis for identifying the causative organism had been a huge challenge. Sending the samples to labs outside the State in proper condition and getting a diagnosis was time consuming.

It was when cases began to be reported on a fairly regular basis — especially since the State issued a directive that all AES samples be tested for amoebic encephalitis too — that the State PH lab was assigned the task of developing molecular test kits for identifying the trophozoite.

“Free living amoeba is an ubiquitous organism found in the environment and till Thursday we had been testing only environmental samples. This is the first time we could identify Acanthamoeba in one of the patient samples,” Dr. Sunija says.

However, testing water samples from the environment becomes important if the organism found in the human samples is Naegleria fowleri. In that case, the waterbody implicated will have to be tested and public warning issued to avoid it.

Published - June 06, 2025 11:00 pm IST