Surveillance for Peste Des Petits Ruminants Virus in Free-Ranging Wildlife of Russia Using an In-House ELISA Assay

Peste des petits ruminants (PPR) is a highly contagious disease caused by the PPR virus (PPRV), a Morbillivirus, that affects small domestic ruminants and a range of wild ruminants. The disease is associated with significant socioeconomic losses and poses conservation threats due to its impact on susceptible wild ungulates. Wild species do not typically serve as independent reservoirs of PPRV. However, spillover from infected livestock at the wildlife–livestock interface is well documented. Therefore, understanding the role of wildlife in PPR epidemiology is important for the global campaign to eradicate the disease. This is the first large-scale surveillance of wild ruminants conducted across the Russian Federation, which included many species that were not previously tested for PPRV. In total, 1709 samples were collected from 19 wild species over 7 years (2018–2024) across 54 regions. All samples were examined using the enzyme-linked immunosorbent assay (ELISA), real-time reverse transcription–polymerase chain reaction, and virus neutralization test (VNT). For the serological component of the study, an indirect ELISA was developed, based on recombinant nucleocapsid protein expressed in Escherichia coli, and was validated. The ELISA was validated against commercial competition ELISA and VNT. Results showed that the ELISA exhibited high performance with serum from multiple species, with a sensitivity of 97.5% and a specificity of 98% compared with the commercial kit, and with a sensitivity of 96.5% and a specificity of 99% versus VNT. All 1709 wildlife samples tested negative for PPRV antibodies and RNA, indicating no evidence of viral circulation in the surveyed populations. Although PPRV has been detected in goitered gazelle (Gazella subgutturosa), saiga (Saiga tatarica), and wild goat (Capra aegagrus) in neighboring countries, none of the Russian specimens—collected from several species, including Caspian red deer (Cervus elaphus maral) and Siberian musk deer (Moschus moschiferus)—tested positive. To the best of our knowledge, this is the first reported widescale PPR surveillance in wildlife species of its kind. This first comprehensive nationwide surveillance of PPRV in wild ruminants across Russia found no infection in the species or samples tested. The newly developed ELISA offers a rapid and reliable cost-effective alternative to VNT for large-scale screening. Our findings indicate that wild ruminants do not currently serve as a PPR reservoir in the surveyed regions and support the inclusion of wildlife monitoring in PPR control strategies for a better understanding of PPR epidemiology in wildlife.