10 open reading frames (ORF 1a, ORF2a, ORF 1b, ORF2b, ORF3-7, ORF5a) encode viral structural proteins (GP2, GP3, GP4, GP5, M, N) and 3'UTR, where ORF
Glycosylated envelope protein (GP5(E)) encoded by ORF5 is one of the most easily mutated protein genes, and some genes overlap. It has no hemagglutination activity and does not agglutinate red blood cells of mammals, poultry and humans.
The pathogen of this disease, also known as Leicester virus, is a reproductive and respiratory syndrome virus composed of nested virus, arteriovirus and arteriovirus. It is oval, with a capsule with a diameter of 40 ~ 60 nm and a protrusion of about 5nm on its surface.
The core-shell is icosahedral with a diameter of 25 ~ 30 nm. The genome is a single-stranded positive-stranded RNA virus with a molecular weight of 1.5× 10? 6。 The length of this RNA is about 15kb, which is not segmented and contains 5' untranslated region, UTR.