Prevalence

Severe systemic PCV2 infection has been reported from almost all swine producing countries. Morbidity due to severe systmic PCV2 infection reportedly varies from as little as 4% to as high as 30% and mortality in affected pigs is typically 70 to 80% (Allan and Ellis, 2000, Harding and Clark, 1997; Madec et al., 2000; Rodríguez-Arrioja et al., 2002). Rodríguez-Arrioja et al. (2002) collected blood samples from 3-, 7-, 12-, and 28-week-old pigs from a PCVAD-affected herd. Clinical PCVAD started when the pigs were 8 weeks old and had a prevalence of 30% in 8- to 10-week-old pigs.

There are two forms of severe systemic PCV2 infection, an endemic and an epidemic form. The endemic form is seen in North America, where severe systemic PCV2 infection usually results in low grade but persistent death losses. Rarely, 3- to 4-fold increase in postweaning mortality can be observed. The epidemic form, which is characterized by persistent mortality, appeared to be observed primarily in Europe but based on recent evidence, has become increasingly observed in eastern Canada (Delay et al., 2005) and North Carolina. Pork producers in Canada and the U.S. have experienced a devastating disease in growing pigs manifest as wasting and pneumonia and resulting in persistent mortality of 20-40% of the pigs between 10 weeks and market age (25 weeks). The recent severe outbreaks most resemble PCVAD and porcine respiratory disease complex (PRDC); however, the severity and persistence of the disease and apparent ability of the disease to spread quickly throughout the area is different then expected with classic PCV2-associated PMWS.

 

References:

Allan GM, Ellis JA: Porcine circoviruses: a review. J Vet Diagn Invest. 12:3-14, 2000

Delay J, McEwen B, Carman S, van Dreuel T, Fairles J: Porcine circovirus type 2-associated disease is increasing. AHL Newsletter. 9:22, 2005

Harding JCS, Clark EG: Recognizing and diagnosing postweaning multisystemic wasting syndrome (PMWS). Swine Health Prod. 5:201-203, 1997

Madec F, Eveno E, Morvan P, Hamon L, Blanchard P, Cariolet R, Amenna N, Morvan H, Truong C, Mahé D, Albina E, Jesting A: Post-weaning multisystemic wasting syndrome (PMWS) in pigs in France: clinical observations from follow-up studies on affected farms. Livestock Prod Sci. 63:223-233, 2000

Rodríguez-Arrioja GM, Segalés J, Calsamiglia M, Resendes AR, Balasch M, Plana-Durán J, Casal J, Domingo M: Dynamics of porcine circovirus type 2 infection in a herd of pigs with postweaning multisystemic wasting syndrome. Am J Vet Res. 63:354-357, 2002