Cross-Sectional Study on the Sero- and Viral Dynamics of Porcine Circovirus Type 2 in the Field

Abstract

Porcine circovirus-associated diseases (PCVADs) cause considerable economic losses in industrial pork production in the field. To minimize the economic losses due to PCVAD, porcine circovirus type 2 (PCV2) vaccines have been developed, and there is widespread vaccination worldwide today. However, limited information is available concerning the current status of PCV2 infection in the field on the Asian continent. The present study aimed to assess sero- and viral dynamics of PCV2 from 12 PCV2-contaminated pig herds with vaccination against PCV2 in Southern and Central Taiwan. In particular, the level of PCV2 load during the window period for seroconversion using real-time polymerase chain reaction and a commercial enzyme-linked immunosorbent assay (ELISA) kit. Our results revealed that pig herds showed slight or no seroconversion after three to four weeks post-PCV2 immunization. The presence of PCV2 was observed during the window period for seroconversion in all herds. In conclusion, natural exposure of PCV2 occurs in the growing to fattening period, and viremia can last until slaughter. Additionally, our findings indicate that using ELISA showed the level of antibodies and aided in the understanding and surveillance of the current PCV2 status in the field.

Seasonal Variation in Prevalence of Mycoplasma hyopneumoniae and Other Respiratory Pathogens in Peri-Weaned, Post-Weaned, and Fattening Pigs with Clinical Signs of Respiratory Diseases in Belgian and Dutch Pig Herds, Using a Tracheobronchial Swab Sampling Technique, and Their Associations with Local Weather Conditions

“…The results obtained concerning PCV-2 dynamics in the current study are in accordance with a recent study on serological and viral dynamics of PCV-2 carried out in PCV-2 infected pig herds in Taiwan [59]. As reported previously, we also observed an increased prevalence during the grow (11.2%) and finish phase (27.1%) [59].…”

Do High Levels of Maternally Derived Antibodies Interfere with the Vaccination of Piglets against Porcine Circovirus Type 2? A Literature Review and Data Analysis

“…We do not have a rational explanation for the better outcomes observed in pigs not showing a vaccine-induced increase in AB titer. However, protection from PCVAD in the absence of a specific serologic response might be due to cellular immunity as all commercially available PCV2 vaccines have been shown to not only induce humoral immune responses, but also cellular immunity [ 25 ]. At least, according to our findings, the absence of seroconversion after vaccination in the presence of high levels of MDA should not be assessed as any negative indicator for the effectiveness of vaccination regarding the main production parameters or viremia.…”

Efficacy Studies of a Trivalent Vaccine Containing PCV-2a, PCV-2b Genotypes and Mycoplasma hyopneumoniae When Administered at 3 Days of Age and 3 Weeks Later against Porcine Circovirus 2 (PCV-2) Infection

“…In addition, PCV-2 vaccines induce not only humoral immunity, but also a cellular immune response [13,30]. Therefore, PCVD protection in the absence of a specific serologic response can be due to cellular immunity [58], and consequently, the absence of seroconversion after vaccination in the presence of MDA should not be assessed as any negative indicator for the effectiveness as it has been observed in some studies [25,28,[59][60][61].…”