Insights into the acute phase of Nipah virus infection: Clinical features, viral detection, and humoral immune response.

OBJECTIVES

This study aimed to explore the humoral immune response and viral detection in the acute phase of Nipah virus (NiV) infection.

METHODS

The study explored clinical and laboratory data from all 22 human NiV cases detected during the 2023, 2024 and 2025 outbreaks in Bangladesh. Oropharyngeal swabs and serum samples were tested for NiV genomic material by real-time reverse transcriptase polymerase chain reaction (RT-PCR); humoral immune response was detected by enzyme-linked immunosorbent assay (ELISA) for immunoglobulin M (IgM) and G (IgG).

RESULTS

A majority of cases were male (64%), and the overall median age of all cases was 21 (0-70) years. The case fatality rate (CFR) was 86% (19/22). 18 (82%) of the cases had evidence of primary infection (a history of recent consumption of raw date palm sap). Viremia on diagnosis resulted in 100% fatality, while CFR was 25% (1/4) in those without detectable viremia. All survivors tested IgG positive on diagnosis, compared to only a third of the fatal cases. Clearance of the virus from the oropharyngeal space started from the 16th to 20th day post-illness onset.

CONCLUSION

The study provides insights into the clinical indices, humoral immune response, and viral detection during NiV infection. This could aid in diagnostic schedules, prognosis, as well as inform isolation and containment strategies.