Nipah Virus Spillover Risks in Kerala and West Bengal Highlight Seasonal Patterns
Nipah Virus Spillover Risks in Kerala and West Bengal Highlight Seasonal Patterns
IN · Published May 13, 2026
Recent analysis of Nipah virus outbreaks in India reveals distinct seasonal and ecological factors driving spillover events in Kerala and West Bengal.
Kerala experiences heightened risk from April to September, coinciding with pre-monsoon and monsoon months when bats forage near human settlements and fruiting trees are abundant.
In contrast, West Bengal's risk peaks from November to April during the date palm sap harvesting season, a known route for foodborne transmission.

Why It's Important?

The Nipah virus poses significant health risks, with case fatality rates often exceeding 60%. Kerala's recurrent spillovers are linked to bat roosts near human settlements, increasing exposure to contaminated fruit. West Bengal faces risks from raw date palm sap consumption during the harvesting season, which has led to nosocomial transmission in healthcare settings. Healthcare workers remain particularly vulnerable, as demonstrated by recent cases in Barasat, West Bengal. The ecological and seasonal factors driving these outbreaks underscore the need for region-specific interventions to mitigate spillover risks. Without sustained surveillance and infection control measures, the potential for larger outbreaks remains a concern.

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