Porcine Reproductive and Respiratory Syndrome Virus
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Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is a virus that causes a disease of pigs, called Porcine Reproductive and Respiratory Syndrome (PRRS). This economically important pandemic disease causes reproductive failure in breeding stock and respiratory tract illness in young pigs. Initially referred to as "mystery swine disease," it was first reported in 1987 in North America (2) and Central Europe (3). The disease costs the United States swine industry around $600 million annually.
Classification
PRRSV is a small, enveloped RNA virus. It contains a single-stranded, positive-sense, RNA genome with a size of approximately 15 kilobases. The genome codes for nine open reading frames.PRRSV is a member of the genus Arterivirus, family Arteriviridae, order Nidovirales. There are three other members of the genus Arterivirus, they are: Equine Arteritis Virus (EAV), Simian Hemorrhagic Fever Virus (SHFV), and Lactate Dehydrogenase-Elevating Virus (LDV) (4-5).
Strains
There are two prototype strains of PRRSV. The North American strain is VR-2332 and the European strain is the Lelystad Virus (LV). The European and North American PRRSV strains cause similar clinical symptoms, but they represent two distinct viral genotypes whose genomes diverge by approximately 40% (6), thus creating a veil of mystery about the origin of this virus. The genetic variation among the viruses isolated from different places (7-8) increases the difficulty of developing vaccines against it.References
- Benfield D, Collins J, Dee S, Halbur P, Joo H, Lager K, et al. Porcine reproductive and respiratory syndrome. In: Straw BE, D’Allaire S, Mengeling WL, Taylor DJ, editors. Diseases of the swine. 8th ed. Ames, Iowa: Iowa State University Press; 1999. p. 201–32.
- Collins J, Benfield D, Christianson W, Harris L, Hennings J, Shaw D, et al. Isolation of swine infertility and respiratory syndrome virus (isolate ATCC VR-2332) in North America and experimental reproduction of the disease in gnotobiotic pigs. J Vet Diagn Invest 1992;4:117–26
- Wensvoort G. Lelystad virus and the porcine epidemic abortion and respiratory syndrome. Vet Res 1993;24:117–24
- Cavenagh D. Nidovirales: a new order comprising Coronaviridae and Arteriviridae. Arch Virol 1997;142:629–33
- Thiel HJ, Meyers G, Stark R, Tautz N, Rumenapf T, Unger G, Conzelmann KK., Molecular characterization of positive-strand RNA viruses: pestiviruses and the porcine reproductive and respiratory syndrome virus (PRRSV). Arch Virol Suppl. 1993;7:41-52
- Nelsen C, Murtaugh M, Faaberg K. Porcine reproductive and respiratory syndrome virus comparison: divergent evolution on two continents. J Virol 1999;73:270–80
- Kapur V, Elam MR, Pawlovich TM, Murtaugh MP. Genetic variation in porcine reproductive and respiratory syndrome virus isolates in the midwestern United States. J Gen Virol. 1996 Jun;77 ( Pt 6):1271-6
- Meng XJ, Paul PS, Halbur PG, Morozov I.Sequence comparison of open reading frames 2 to 5 of low and high virulence United States isolates of porcine reproductive and respiratory syndrome virus. J Gen Virol. 1995 Dec;76 ( Pt 12):3181-8
External links
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