IAV-developed antibody test aims to identify hidden Nipah pathways

THIRUVANANTHAPURAM: With recurrent Nipah outbreaks leaving more questions than answers, the state has launched a critical sero-surveillance initiative aimed at uncovering hidden transmission pathways. A new testing kit, developed by the Institute of Advanced Virology (IAV), is at the core of the effort designed to detect Nipah antibodies in both humans and animals. With no conclusive understanding yet of how the virus makes the leap from bats to humans, this surveillance aims to identify possible intermediate animal hosts by analysing blood samples for antibodies. What sets this kit apart is its versatility: Unlike conventional approaches that require separate testing kits for each species, the IAV kit, which employs pseudovirion technology, can detect antibodies in both humans and multiple animal species. According to experts, this may help determine whether subclinical infections in animals or humans will potentially evolve into more severe forms of the disease. Crucially, the testing process does not require a biosafety level 4 (BSL-4) laboratory -- a major breakthrough, given that Kerala currently lacks such a facility. We still dont know how Nipah is transmitted from bats to humans. While we know that bats carry antibodies and humans fall ill, the spillover mechanism remains elusive, said Dr Easwaran Sreekumar, director of Thonnakkal, Thiruvananthapuram-based IAV. Traditional studies are limited because the virus often isnt detectable in blood, and handling it typically requires a BSL-4 lab. This new assay system gives us a way forward, he added. Dr Sreekumar emphasised that if antibodies are detected in a particular animal species, that species can then be closely monitored for symptoms and potential human transmission. There are many hypotheses. We can begin addressing them only when we have the right tools, and this is a major step, he said, adding that testing of human samples will begin soon. The kit was first validated using blood samples collected in 2023 from Nipah-infected individuals in Malappuram. It has since been used to test domestic animals in Palakkad and Malappuram districts, marking a significant expansion in surveillance efforts. The IAV has collaborated with the animal husbandry department to collect samples. Dr Sanjay Devarajan, disease investigation officer at State Institute of Animal Diseases (SIAD), Palode, said that samples from cats, dogs and cattle within a 1km radius in both districts have been sent for testing. Detection of antibodies in domestic animals can play a major role in shaping future Nipah prevention policies and issuing timely health advisories, Dr Devarajan said. According to Dr T S Anish, professor and nodal officer at the Kerala One Health Centre for Nipah Research and Resilience, Kozhikode Government Medical College, the new antibody testing system has valuable applications. It can help answer critical questions -- such as which animals act as reservoirs or how the virus jumps to humans. Stored blood samples could still be tested, Dr Anish said. He, however, noted that this cannot replace PCR testing for detecting active infections.