Occurrence of single and mixed rotavirus infections in large-scale pig farms in Russia.

Abstract

Enteric disease outbreaks are among the major causes of economic damage in the pig industry worldwide, and they have a considerable impact on farming in Russia, one of the world's largest pork producers. Infectious agents can contribute to these outbreaks, with some viruses, such as rotaviruses (RVs), playing a crucial role. During 2023-2025, we tested 774 porcine diarrheic samples submitted from 22 large-scale pig farms in Russia for the presence of RVA, RVB, and RVC in different age groups. RVA was detected in 32.43%, RVB in 13.18%, and RVC in 13.95% of the samples, respectively. The highest total detection rate was observed in weaned piglets (22-36 days), with a rate of 75.2%, followed by age groups 1-10 days (42%), 66-80 days (36.8%), and 11-20 days (31.2%). RVA was the most prevalent in single infections (21.4%), followed by RVB (5.9%) and RVC (5.3%), while the highest frequency of co-infection was found between RVA and RVC (5%). Genetic characterization of the VP7 and VP4 genes of RVA strains revealed a variety of G/P genotypes, including G3, G4, G5, and G9, as well as P[6], P[13], and P[23]. The most common combinations were G4P[23], G4P[6], and G3P[13]. Genotyped RVC strains were characterized by G6 for VP7 and P[5] and P[6] for VP4, and the G6P[5] combination was predominant. This study fills a knowledge gap and offers fresh perspectives on the molecular epidemiology of RV species in pig herds in Russia whilst underscoring the necessity of ongoing rigorous monitoring to control the epidemiological situation.