Surveillance of equine glanders in India (2019-2023): Prevalence estimate, risk analysis and future strategy.

Surveillance of equine glanders in India from 2019 to 2023 detected a decline in disease prevalence, identified regional and seasonal risk factors, and highlighted the need for enhanced monitoring and control measures to reduce the spread of this zoonotic disease.

Overview of Equine Glanders and Study Purpose

• Equine glanders is a zoonotic disease caused by the bacterium Burkholderia mallei, affecting equids such as horses, mules, and donkeys.
• The disease is notifiable, meaning it must be reported to authorities due to its serious impact on animal health and potential human transmission.
• This study aimed to assess the prevalence, distribution, temporal trends, and risk factors of glanders in Indian equid populations through a large-scale surveillance program conducted from 2019 to 2023.
• Results intended to inform future disease control strategies in India.

Methodology of the Surveillance Program

• The study collected 158,798 serum samples from equids across 391 districts in 19 states and 3 union territories of India over five years.
• Screening was performed using an Hcp1-based indirect ELISA test, a serological method to detect antibodies specific to Burkholderia mallei.
• Positive samples were further confirmed using the complement fixation test (CFT), a standard confirmatory serological assay for glanders.

Key Findings on Prevalence and Distribution

• A total of 728 seropositive equids were identified in 138 out of the 391 districts surveyed.
• Overall seroprevalence decreased significantly, from 0.627% in 2019 to 0.253% in 2023, indicating progress in disease control.
• This decline is attributed to the implementation of the National Action Plan for Glanders launched in 2019.
• Uttar Pradesh state accounted for approximately 60% of all positive cases, likely due to intensive equine trade and movement in this region.
• Seasonal variation was noted with the highest seroprevalence during winter months (0.569%) versus spring-summer (0.377%) and monsoon (0.43%).
• The East Coast Plains and Hills agroclimatic region showed the highest prevalence at 1.462%, signifying regional differences in disease burden.

Identified Risk Factors for Disease Persistence

• Equids managed in unorganized systems — where animals are kept and handled without strict oversight or biosecurity — were at higher risk.
• Frequent movement of equids for cultural events and trade contributed to disease spread.
• There was insufficient awareness regarding glanders regulatory policies among field veterinarians, hampering early detection and control efforts.

Recommendations and Future Strategies

• Enhanced surveillance is advised, especially in southern, eastern, and northeastern India, targeting 10-15% or more of the equid population to improve case detection.
• Strengthening regulations and awareness around equid movement, including measures for cultural event-related animal transport, is critical.
• Given the zoonotic potential of glanders, testing of humans in close contact with equids is recommended to prevent and control transmission to people.
• Ongoing monitoring and integration of serological data can help track progress and refine disease control programs.

Importance and Impact

• The study provides comprehensive, large-scale surveillance data on glanders, a significant animal and public health concern in India.
• It highlights the effectiveness of national-level interventions while also identifying challenges that remain.
• Results help policymakers, veterinary officials, and public health authorities to prioritize resources and improve disease management to protect both equids and humans.