Porcine Parvovirus

Introduction

Porcine Parvovirus is a worldwide disease of pigs. There is only a single serotype of this virus and it affects only pigs.

The virus is the principal cause of SMEDI syndrome: Stillbirths, Mummification, Embryonic Deaths, and Infertility, which is responsible for serious economic loss in pigs. There will usually be a whole litter born, with some weak but alive, some stillbirths and some mummified foetuses. This demonstrates the virus acting over the period of gestation.

The virus replicates in gastrointestinal epithelium followed by viraemia, transplacental infection occurs in early pregnancy, with some (but not all) surviving piglets living as carriers. The virus is transmitted orofaecally or via fomites. About 50% of UK pigs are antibody-positive. Outbreaks occur as herd is developing immunity and congenitally infected piglets act as herd reservoir.

Clinical Signs

There are often no clinical signs other than coming back into heat in early pregnancy or the birth of mummified foetuses. There may be a transient pyrexia when the disease is in the viraemic stage, but this is unlikely to be noticed by stockmen.

Diagnosis

History and clinical signs are very characteristic of the disease with mummified foetuses etc.

Immunostaining of fetal tissues, along with virus isolation in cell culture and haemagluttination inhibition (HAI) on feces can be performed to gain a definitive diagnosis. Serology can be used to detect rising antibody titres in paired serum sample by HAI.

Control

Inactivated vaccine (UK) or live attenuated (USA) is available and widely used. Infected piglets should be culled and their carcasses disposed of correctly.

References

Cowart, R.P. and Casteel, S.W. (2001) An Outline of Swine diseases: a handbook Wiley-Blackwell

Straw, B.E. and Taylor, D.J. (2006) Disease of Swine Wiley-Blackwell

Taylor, D.J. (2006) Pig Diseases (Eighth edition) St Edmunsdbury Press ltd