Avian paramyxovirus serotype-1 isolation from migratory birds and environmental water in southern Japan: an epidemiological survey during the 2018/19–2021/2022 winter seasons

Abstract

Abstract An epidemiological survey of avian paramyxovirus serotype-1 (APMV-1) was conducted in the Izumi plain, Kagoshima, Japan from the winter of 2018–2022. A total of 15 APMV-1 were isolated from roosting water of migratory birds and duck fecal samples. The APMV-1 isolation rate from the water and duck feces were 2.51% and 0.10%, respectively, demonstrating that the viral recovery efficiency from the water was 25-fold higher than that from duck feces. Genetic analysis of the Fusion (F) gene showed that all of the APMV-1 isolates were closely related to virus strains circulating among waterfowl in Far East Asian countries. All isolates have avirulent motifs in their cleavage site of F genes, indicated that all of which were presumed to be low pathogenic viruses in poultry. However, pathogenicity test using embryonated chicken eggs demonstrated that some isolates killed all chicken embryos regardless of viral inoculated doses (102-106 50% egg infectious dose). These results indicated that these APMV-1 viruses which are potentially pathogenic to chickens are continuously brought into the Izumi plain by migrating of wild birds.