High Prevalence of PCV2 Viraemia Found in Clinically Normal Breeding Herds

A high prevalence of porcine circovirus type 2 (PCV2) viraemia has been found in newborn piglets in five clinically normal pig breeding herds in North America by resarchers at Iowa State University.

3 November 2010

4 minute read

H. Shen and colleagues at Iowa State University have investigated the prevalence of PCV2 in five breeding herds in the US and Mexico, and found that almost all sow colostrum and more than 20 per cent of newborn piglets were positive for anti-PCV2 IgG antibody. Their paper is published in Preventive Veterinary Medicine.

The paper's authors explain that porcine circovirus type 2 (PCV2) can be vertically transmitted resulting in foetal infection with or without clinical signs and lesions.

The primary objective of their study was to assess the prevalence of intrauterine PCV2 infection in clinically normal newborn piglets in conventional pork production facilities.

Five commercial breeding herds located in the US and Mexico were included in the study. A total of 125 sows and three to five neonatal piglets per sow were arbitrarily selected. Blood and colostrum samples were collected from sows. Blood was collected from piglets prior to suckling.

All samples were analysed for the presence of anti-PCV2 IgG antibodies and presence and amount of PCV2 DNA. In addition, PCV2 DNA positive samples were further subtyped into PCV2a and PCV2b. All (125/125) sow colostrum samples and 96.8 per cent (121/125) of the sow serum samples and 21.4 per cent (107/499) of the piglet pre-suckle serum samples were positive for anti-PCV2 IgG antibody.

The overall PCV2 DNA prevalence was 47.2 per cent (59/125) in sow serum, 40.8 per cent (51/125) in sow colostrum, and 39.9 per cent (199/499) in pre-suckle piglet serum.

In the PCV2 DNA-positive samples, PCV2b was detected at a higher frequency (69.5 per cent for sow serum, 84.3 per cent for sow colostrum, and 74.4 per cent for piglet serum) compared to PCV2a (18.6 per cent for sow serum, 9.8 per cent for sow colostrum, and 15.6 per cent for piglet serum).

Concurrent PCV2a and PCV2b infection was detected in 11.9 per cent of the sow serum, in 5.9 per cent of the colostrum samples, and in 10.0 per cent of the piglet serum samples.

Shen and co-authors concluded that an unexpectedly high prevalence of PCV2 viraemia was detected in healthy sows (serum and colostrum) and their pre-suckle piglets in the five breeding herds investigated and PCV2b was more prevalent than PCV2a. They added that this information adds to the knowledge of PCV2 infection in breeding herds.

Reference

Shen H., C. Wang, D.M. Madson and T. Opriessnig. 2010. High prevalence of porcine circovirus viremia in newborn piglets in five clinically normal swine breeding herds in North America. Preventive Veterinary Medicine, article in press. doi:10.1016/j.prevetmed.2010.09.020