New test reveals Nipah virus spread among Indian pigs, raising spillover concerns

Nipah virus has killed people across South and Southeast Asia for decades, arriving without warning from fruit bats and moving through pigs before jumping to humans. It causes a brain infection that often proves fatal. Stopping it means catching it early—in animals, before it reaches people. A team of Indian researchers has now built a tool to do exactly that.

Scientists at India's National Institute of Veterinary Epidemiology and Disease Informatics developed a new diagnostic test designed to detect Nipah antibodies in pig blood. The test, called NiV-rN-iELISA, works by identifying a specific viral protein that the body produces when infected. When the researchers compared their homemade test against a commercial version already in use, it matched the commercial standard with 85% accuracy on negative samples and nearly 85% on positive ones—close enough to be trusted for real-world surveillance.

Then they deployed it. Between 2018 and 2019, and again in 2024 and 2025, the team tested blood samples from 741 pigs across seven districts in Kerala state, a region where fruit bats, pigs, and humans live in close proximity. What they found was a patchwork of infection. Across five districts, the average rate of pigs carrying Nipah antibodies sat at 5.67 percent—meaning those animals had been exposed to the virus at some point. But the numbers were not evenly distributed. In Ernakulam district, nearly one in four pigs tested positive, reaching 24.03 percent. When the researchers mapped these results geographically, they discovered something crucial: the virus was not scattered randomly. It clustered. Specific neighborhoods within specific districts showed concentrations of infected animals, creating what epidemiologists call hotspots.

This matters because it changes how you think about prevention. A hotspot is not just a number on a chart—it is a place where the conditions for spillover are especially ripe. Fruit bats roost nearby. Pigs live in farms or semi-domestic settings. Humans work with the animals, handle them, live alongside them. When a virus circulates in that triangle, the risk of jumping species rises. The test gives public health officials a way to find those triangles before an outbreak happens.

The researchers framed their work as part of India's National One Health Mission, a government initiative that treats human health, animal health, and environmental health as interconnected. The logic is straightforward: you cannot protect people from a zoonotic virus by only watching humans. You have to watch the animals that carry it. You have to know where the virus is circulating in pig populations, how often, and in which places. Then you can station resources, educate farmers, improve biosecurity, and prepare hospitals.

The test itself is significant because it was developed in-house, using recombinant viral proteins made in the laboratory rather than relying entirely on imported commercial kits. That matters for a country like India, which faces repeated Nipah threats and cannot always wait for external suppliers. It also means the test can be adapted, refined, and deployed quickly across the region.

What happens next depends on whether this surveillance becomes routine. The researchers have shown that the tool works and that it reveals a real problem—Nipah is circulating in Kerala's pig population, unevenly, in clusters. The question now is whether that knowledge translates into action: whether officials use these hotspot maps to strengthen monitoring, whether farmers receive guidance on reducing contact between bats and pigs, whether hospitals in high-risk areas prepare for potential cases. The test is ready. The data is clear. The next move belongs to the people who can turn surveillance into prevention.