Guwahati: The peste des petits ruminants virus (PPRV), a highly contagious livestock virus, crossed species and institutional safeguards when it spread from infected domestic goats to captive endangered deer at the Assam State Zoo in 2021.
A peer-reviewed study published in November 2024 has confirmed that the outbreak resulted in the deaths of 30 animals from five cervid species, likely due to exposure to contaminated goat meat and environmental transmission.
The findings, published in the international journal “Viruses”, represent the first confirmed detection of PPRV in the Cervidae family and indicate a lapse in biosecurity within one of Northeast India’s major wildlife institutions.
The outbreak occurred between late February and mid-March 2021, starting with unexplained deaths of barking deer and spreading to four-horned antelope, hog deer, thamin, and mouse deer housed in the zoo’s cervid enclosure.
Several animals died without prior clinical symptoms, delaying identification of the outbreak until mortality increased.
Researchers from Assam Agricultural University, in collaboration with zoo veterinarians and WWF-India, confirmed the disease through RT-PCR testing, pathological examination, and genetic sequencing.
All samples tested positive for Lineage IV PPRV, a strain widely circulating across South Asia.
Investigation of the zoo’s supply chain found that raw goat meat used to feed carnivorous animals tested positive for PPRV, as did tissue samples from domestic goats collected from nearby districts during earlier outbreaks.
Genetic analysis showed close similarity between viral sequences from goats and infected deer, indicating a livestock-to-wildlife spillover.
Post-mortem examinations revealed lung congestion, hemorrhages across multiple organs, ulcerative oral lesions, and depletion of immune tissues, consistent with acute PPR infection. Pregnant four-horned antelopes aborted infected fetuses, suggesting possible vertical transmission within wildlife.
While serow and chital populations were unaffected, four-horned antelopes experienced mortality exceeding 80 percent, reflecting species-specific vulnerability.
PPR is a WOAH-notified transboundary disease targeted for global eradication by 2030. Scientists note that circulation in domestic livestock, combined with limited biosecurity at wildlife facilities, could affect both conservation measures and eradication efforts.
The Assam State Zoo outbreak demonstrates the need for integrated livestock–wildlife disease surveillance and screening of animal products to maintain protection in wildlife facilities.