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.

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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 contains nine open reading frames (Meulenburg et al., 1992, Lee and Yoo, 2005).

PRRSV is a member of the genus Arterivirus, family Arteriviridae, order Nidovirales.[1] 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. Similarly, there is difficulty in maintaining diagnostic PCR detection assays due to the high mutation rate of this virus, see Risk of Missed PRRS PCR Detection.

See also

References

  1. ^ Balasuriya and Snijder (2008). "Arteriviruses". Animal Viruses: Molecular Biology. Caister Academic Press. ISBN 978-1-904455-22-6. http://www.horizonpress.com/avir. 

External links