Identification of a new unusual length polymorphism of the nucleocapsid protein in porcine reproductive and respiratory syndrome virus.

All twenty-nine PRRSV ORF7 nucleotide sequences obtained from clinical samples originating from the three Central European countries Austria (n = 7), Czech Republic (n = 12), and Slovakia (n = 10) belonged to type 1, subtype I (EU-1). Twenty-seven sequences encoded the typical length of the nucleocapsid protein composed of 128 amino acids. Two genetically identical ORF7s of PRRSV originating from a single farm in Slovakia showed a new length polymorphism of the nucleocapsid protein comprising 132 amino acids.