P-586. 2025 Nipah Outbreaks in Bangladesh: Clinical Patterns, Emerging Risks, and Future Preparedness in an Expanding Epidemiologic Landscape

Abstract Background Nipah virus (NiV), a high-risk pathogen with pandemic potential, causes near-annual outbreaks in Bangladesh. Since January 2025, the Institute of Epidemiology, Disease Control and Research (IEDCR) and icddr,b have investigated three NiV outbreaks.Table 1:Demographic, Epidemiological, and Clinical Findings of Nipah Cases in the 2025 Outbreaks in BangladeshTable 2:Laboratory Test Results of Nipah Cases in the 2025 Outbreaks in Bangladesh Methods Structured and informal interviews with case families, contacts, and communities explored exposures, disease history, risk behaviors, possible spillover, and transmission routes. Oropharyngeal swabs and sera were tested in high-risk contacts and same-source exposed individuals for NiV RNA (RT-qPCR) and anti-NiV IgM (ELISA).Figure 1:Geospatial Mapping of Key Locations of the 2025 Nipah Outbreaks in Bangladesh Results Three sporadic NiV outbreaks were detected in urban or peri-urban areas of Pabna, Bhola (first-ever case), and Faridpur districts between January 29 and February 26 in 2025. All were primary cases linked to raw date palm sap (DPS) consumption. Bat roosts near source date palm trees (2-13 km) housed 20-500 Pteropus medius bats each. Cases tested NiV-positive within 4-11 days of symptom onset (incubation period: 3-13 days) and 2-3 days post-hospitalization (hospitalization lag time: 1-9 days). All presented with fever, varied neurological symptoms (seizure, blurry vision, altered sensorium, limb weakness), and respiratory distress, and died within 3-12 days of onset. We identified 244 contacts; 10 same-source exposures (raw DPS), of which 7 were also contacts. All 140 high-risk contacts and same-source exposed individuals tested NiV-negative. Investigations revealed widespread raw DPS consumption, even among the urban populations and beyond past outbreak areas, daytime harvesting for sweetness instead of overnight collection practice, and nighttime consumption in contrast to traditional morning intake. Conclusion As in 2024, fatality in all 2025 NiV cases confirms sustained NiV virulence in Bangladesh. Widespread raw DPS consumption and delays in care-seeking highlight the critical need for community awareness. To map new exposure risks and comprehend community risk perception, further investigation is needed into evolving DPS collection and consumption practices. Surveillance at lower-tier facilities, developing local diagnostic capacity, and physician training could aid early detection, reduce diagnostic delays, and improve healthcare delivery and patient outcomes. Disclosures All Authors: No reported disclosures