Porcine respiratory and reproductive syndrome virus variants, Vietnam and China, 2007

Abstract

We characterized isolates from porcine respiratory and reproductive syndrome virus epidemics in Vietnam and China in 2007. These isolates showed approximately 99% identity at the genomic level. Genetic analysis indicated that they share a discontinuous deletion of 30 aa in nonstructural protein 2, which indicates that identical variants emerged in Vietnam and China.

Figure 1

Pathologically dissected specimens from pigs infected by porcine respiratory and reproductive syndrome viruses. Blood spots in kidneys and lung hemorrhages are indicated by white arrows.

Figure 2

Whole genome–based phylogenetic relationship of porcine respiratory and reproductive syndrome viruses (PRRSVs) LV4.2.1, the prototype of type I (European PRRSV) (shown in green), and VR2332, the standard strain of type II (North American PRRSV) (shown in pink). Three Chinese isolates reported before 2006 (HB-1, HB-2, and CH-1a) are shown in blue. Chinese 2006 PRRSV isolates are shown in purple. Chinese 2007 isolates are shown in black boldface, and a representative of 2007 Vietnamese strains (07QN) is shown in red boldface. The 2007 Vietnamese and Chinese PRRSV isolates are classified into the same subclade of type II, as are all the 2006 Chinese PRRSV strains.