Sero-positivity of Japanese Encephalitis Virus in Equine Population of India Using IgG ELISA: Unraveling the Need for Vaccination.
Authors: Kapdi Aarti, Dhanze Himani, Sahu Anamika, Singh Vijayata, Kumar Murthy Suman, Bhilegaonkar Kiran Narayan, Gulati Baldev Raj
Journal: Journal of equine veterinary science
Summary
# Japanese Encephalitis Virus in Indian Equine Populations: Sero-surveillance Data Highlights Vaccination Gap Researchers from India developed and validated a recombinant NS1 protein-based indirect IgG ELISA to assess exposure to Japanese encephalitis virus (JEV) across the equine population, addressing the lack of affordable, domestically produced diagnostic tools for sero-surveillance in a region where the disease remains endemic and unvaccinated horses face significant risk. Testing 2,069 serum samples, they identified an overall sero-positivity of 19.38%, with concerning regional variation—notably 25.90% in Himachal Pradesh and 12.22% in Jammu-Kashmir, extending JEV exposure beyond previously documented endemic zones to non-endemic northern hill states. The developed ELISA demonstrated good diagnostic performance (84.73% sensitivity, 86.70% specificity) with reproducible results across laboratories (kappa values 0.75–1.0), establishing it as a reliable surveillance tool. These findings reveal substantial ongoing exposure to JEV in the Indian equine population without corresponding vaccination programmes, creating both animal welfare and potential zoonotic public health concerns. The data provide compelling evidence for initiating equine JEV vaccination strategies across India, particularly in newly identified risk areas, whilst the validated ELISA offers a cost-effective means for veterinary practitioners and regulatory bodies to monitor disease prevalence and evaluate vaccination programme effectiveness.
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Practical Takeaways
- •Nearly 1 in 5 horses in India have been exposed to Japanese encephalitis virus, indicating widespread circulation—vaccination programs should be implemented to protect unvaccinated populations at risk
- •JEV is spreading beyond traditionally endemic areas to hill states; equine practitioners should consider JEV in differential diagnosis for encephalitis cases in North India and maintain awareness of evolving geographic distribution
- •The newly developed indigenous IgG ELISA offers a cost-effective alternative to imported diagnostic kits, enabling routine sero-surveillance to monitor JEV prevalence in equine populations and guide vaccination decisions
Key Findings
- •Overall sero-positivity of JE virus in Indian equine population was 19.38% (401/2069 samples)
- •Developed recombinant NS1 protein-based IgG ELISA demonstrated 84.73% diagnostic sensitivity and 86.70% specificity
- •Sero-positivity of 25.90% in Himachal Pradesh and 12.22% in Jammu-Kashmir indicates spread of JEV to previously non-endemic regions
- •High sero-positivity rates indicate unvaccinated horses are at significant risk of JEV infection across India