Porcine Reproductive and Respiratory Syndrome Virus

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), also known as Blue-Ear Pig Disease (in Chinese, zhū láněr bìng 豬藍耳病), 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" and "mystery reproductive syndrome," 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".cite book |chapterurl=http://www.horizonpress.com/avir|author=Balasuriya and Snijder|year=2008|chapter=Arteriviruses|title=Animal Viruses: Molecular Biology|publisher=Caister Academic Press|id= [http://www.horizonpress.com/avir ISBN 978-1-904455-22-6] ] 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).

trains

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.

Chinese Epidemic

On September 8, 2006, news of a PRRS epidemic brewing in China, then known as "High Fever Disease", was published in English via ProMed-mail. The epidemic has received little attention outside China, but has had far reaching effects on the Chinese economy, leading to the highest inflation seen in a decade, and affecting 25 of the 33 Chinese provinces. While so far the epidemic has been most catastrophic along the Southern and Eastern coasts of the nation, concerns have arisen that the disease will strike the inland Sichuan province, the center of the Chinese pork industry. Meanwhile, pork prices are skyrocketing both within China, and internationally, with prices up as much as 85% in Chinese markets. It does not appear that the epidemic poses any direct risks to human health. (9)

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
*Barboza, David. Chinese Pig Virus Causes Concern Around the Globe. The New York Times. August 15, 2007.

ee also

*Animal viruses
*Virology
*Nidovirales

External links

* [http://prrsvdb.org Porcine Reproductive and Respiratory Syndrome Virus Database]
* [http://www.nytimes.com/2007/08/16/business/worldbusiness/16pigs.html?hp New York Times article on the 2007 epidemic]
*cite news
title=Europe's piglets die in mystery plague
publisher=New Scientist
date=May 4, 1991
url=http://www.newscientist.com/article/mg13017671.900-europes-piglets-die-in-mystery-plague-.html
accessdate=2007-06-28
* [http://www.horizonpress.com/gateway/animal-viruses.html Animal viruses]
* [http://www.PRRSResearch.com PRRS Research Award for PRRS Eradication ]
* [http://www.PADRAP.org PADRAP Production Animal Disease Risk Assessment Program PRRS Risk Survey]
* [http://www.horizonpress.com/gateway/animal-viruses.html Animal viruses]