title: Comparison of the virulence of European and North American genotypes of porcine reproductive and respiratory syndrome virus in experimentally infected pigs.
abstract: The objective of this study was to compare the virulence of Korean types 1 and 2 porcine reproductive and respiratory syndrome virus (PRRSV) isolated from weaned pigs with respiratory disease. Affected pigs were within the same herd and animals infected with type 2 virus had significantly higher mean rectal temperatures than those with type 1 virus between days 2 and 9 post-inoculation (P<0.05). Similarly, mean serum viral titres, expressed as tissue culture infective doses 50% (TCID50)/mL, as well as macroscopic and microscopic pulmonary lesion scores, were significantly higher at multiple time points in pigs infected with type 2 PRRSV compared to those infected with type 1 virus. Mean numbers of PRRSV-positive cells/unit area of lungs and lymph nodes were also significantly higher in type 2 PRRSV infected pigs. This study demonstrates that type 2 PRRSV is more virulent than type 1 PRRSV in this experimental setting as reflected by the pulmonary pathology induced, the extent of virus distribution, and oral shedding of the virus.
authors: Seoul National University, College of Veterinary Medicine, Department of Veterinary Pathology, 599 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
authors: K
authors: K
authors: Han
authors: H W
authors: HW
authors: Seo
authors: Y
authors: Y
authors: Oh
authors: I
authors: I
authors: Kang
authors: C
authors: C
authors: Park
authors: C
authors: C
authors: Chae
mesh_terms: D000818:Animals; D005060:Europe / Q000453:epidemiology; D005838:Genotype; D009656:North America / Q000453:epidemiology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000472:pathogenicity*; D012367:RNA, Viral / Q000235:genetics; D013552:Swine; D013997:Time Factors; D014774:Virulence
chemical_list: D012367:RNA, Viral