Nipah virus in South Asia: from emergence to enduring preparedness' challenges

Nipah virus (NiV) is a highly lethal zoonotic virus that has caused sporadic but severe outbreaks in South and Southeast Asia since its emergence in 1998. Despite the relatively small size of most outbreaks, NiV poses a substantial public health challenge due to its high case fatality rate.

To examine the evolving epidemiology, clinical features, virological insights, and preparedness challenges associated with NiV infection in South Asia.

We conducted a narrative review synthesising epidemiological, clinical, and public health data from national surveillance systems, WHO Disease Outbreak News reports, and published outbreak investigations.

We describe the shift from pig-amplified transmission observed in Malaysia to bat-driven spillover and human-to-human transmission, particularly within household and hospital settings, as characterised by recent outbreaks in Bangladesh and eastern India, and specifically review Kerala's experience since 2018. Particular attention is given to the re-emergence of NiV in West Bengal in early 2026, involving a limited cluster of infections among healthcare workers that was rapidly contained but remains epidemiologically important given the region's prior history of nosocomial spread. We discuss persistent challenges in early diagnosis, access to high-containment laboratory testing, and clinical management, alongside emerging roles for mobile Biosafety Level 3 laboratories and point-of-care diagnostics.

Overall, the South Asian experience underscores that NiV represents a persistent zoonotic threat rather than an episodic emergence, necessitating sustained preparedness, pathogen-agnostic clinical vigilance, and proportionate risk communication to mitigate future outbreaks. Sustained preparedness, rather than episodic alarm, must guide future responses.