Novel goose parvovirus as a major risk factor for red skin and bristle feather syndrome in meat ducks: Epidemiological associations with duck circovirus and reovirus.

In recent years, a disease characterized by dorsal skin reddening and feather development disorder, termed "red skin and bristle feather syndrome" (RSBFS), has emerged in meat duck farms in China, resulting in substantial economic losses. To clarify the major etiological risk factor, their epidemiological patterns, and molecular characteristics, we collected 300 clinical samples from symptomatic and asymptomatic ducks across eight major duck-producing provinces in China between February and July 2025. Multipathogen screening was conducted using quantitative real-time PCR, followed by phylogenetic analysis of the major pathogens. The results identified duck circovirus (DuCV), novel duck reovirus (NDRV), and waterfowl parvovirus (WPV) as the dominant pathogens, with detection rates of 66.44% (194/292), 32.33% (86/266), and 19.18% (56/292), respectively. Among the detected pathogens, monoinfection with WPV-predominantly represented by novel goose parvovirus (NGPV)-showed a strong positive association with RSBFS (OR = 9.85, 95% CI: 4.89-19.84). It was identified as a major etiological risk factor for disease occurrence. Although DuCV or NDRV monoinfection did not exhibit significant pathogenicity, their coinfection with WPV resulted in markedly enhanced interactive effects on disease severity. Epidemiological analysis revealed distinct spatiotemporal clustering, with Shandong province as the main epidemic focus and ducks aged 3 to 5 weeks as the most susceptible group. Genetic evolution analysis indicated that DuCV strains predominantly belonged to genotypes Ib and Ic, the NDRV S1 gene was highly conserved, and NGPV was the dominant subtype of WPV. To our knowledge, this study is the first to identify a strong statistical association of NGPV with RSBFS and to characterize its epidemiological associations with DuCV and NDRV. These findings provide critical epidemiological and molecular evidence for developing targeted vaccines and formulating integrated control strategies in commercial duck production.