Porcine circovirus (PCV) is classified in Circoviridae family and has been detected since 1982 In Thailand, the first PCV detection was reported in nursery pigs in 1999. PCV is classified into 2 types, i.e., PCV type 1 (PCV1) and PCV type 2 (PCV2) PCV1 is not pathogenic, while PCV2 was found to be a primary cause of many clinical symptoms in pigs, e.g., postweaning multisystemic wasting syndrome (PMWS), porcine dermatitis and nephropathy syndrome (PDNS), porcine respiratory disease complex, PRDC) and porcine reproductive disorders. The incidence and the disease pattern of PCV2 have been intensively studied during recent years. However, most study focus on nursery and fattening pigs, study on gilts and sows, especially clinical study, is limited. The objectives of the present study were to 1.) determine the influence of PCV2 infection in gilts and sows on their reproductive performance 2.) study the efficacy of PCV2 vaccination in gilts and sows on reproductive performances and 3.) investigate the prevalence of PCV2 detection in aborted fetuses, mummified fetuses and stillborn piglets. The study was conducted in a 1,700 sows-on production swine breeding herd in Thailand. The antibody titer response after PCV2 vaccination in gilts and sows was investigated. Blood samples were randomly collected from gilts and sows at 0, 2, 4 and 6 weeks after vaccination. Reproductive performance before and after vaccination were analyzed. Reproductive organs, including ovaries and uteri, were collected from slaughtered house and aborted fetuses (n=14), mummified fetuses (n=17) and stillborn piglets (n=9) were collected from swine herds under field conditions. All samples were submitted for PCV2 DNA detection by using PCR. PCV2 antibody titer was determined by using ELISA. The results revealed that PCV2 DNA was detected in 92.5% (37/40 samples) of the analyzed samples. The PCV2 DNA was found in 92.8% (13/14 samples) of aborted fetuses, 94.1% (16/17 samples) of mummified fetuses, and 88.8% (8/9 samples) of aborted fetuses (P>0.05). Vaccination against PCV2 in gilts and sows significantly reduced the variation of antibody titers. The CV of the antibody titer reduced from 38.9% to 23.5%, 20.2% and 18.0% within 2, 4, and 6 weeks after vaccination, respectively. Reproductive performances in both gilts and sows did not alter significantly (P>0.05). Additionally, PCV2 DNA was detected in 45% (46/102) of the uterus and in 30% 30% (21/70) of the ovaries of slaughtered gilts. These findings indicated that PCV2 may involve in reproductive disturbances in gilts and sows under field conditions. Further comprehensively studies on the reproductive failures associated with PCV2 detection in the ovary and uterus are required.
