Changes

==Description==

==Description==

Porcine reproductive and respiratory syndrome was first recognised in the USA in 1987 and spreadto Europe in 1990 and the UK in 1991. Infection in the UK was initially seen in the Humberside area, but despite restrictions being placed on the movement of breeding stock outwith the infected zone, the disease spread to many parts of the country. PRRS is caused by a virus, of which different strains occur in the USA and Europe. The european strains are much milder in terms of their pathogenic potential than the US strains. The acute phase of disease lasts approximately 4-16 weeks. The most consistent featurs are reproductive lossed in pregnant stoock, increased pre-weaning mortality and inluenza-like illness affecting all ages of pigs. American strains of virus are much more virulent than European strains, causing sow martality in addidion to pneumonia and reporductive failure.

Porcine reproductive and respiratory syndrome (PRRS) first appeared in the USA in 1987 and spreadto Europe in 1990 and the UK in 1991. Infection in the UK was initially seen in the Humberside area, but despite restrictions being placed on the movement of breeding stock outwith the infected zone, the disease spread to many parts of the country. PRRS is caused by a virus, of which different strains occur in the USA and Europe. The european strains are much milder in terms of their pathogenic potential than the US strains. The acute phase of disease lasts approximately 4-16 weeks. The most consistent featurs are reproductive lossed in pregnant stoock, increased pre-weaning mortality and inluenza-like illness affecting all ages of pigs. American strains of virus are much more virulent than European strains, causing sow martality in addidion to pneumonia and reporductive failure.

Porcine reproductive and respiratory syndrome (PRRS)

Porcine reproductive and respiratory syndrome (PRRS)