Abstract
Vaccination against porcine circovirus 2 (PCV-2) is a common practice all over the world. Vaccines can prevent PCV-2-systemic disease (PCV-2-SD) outbreaks but not PCV-2 infection, which can be detectable in a percentage of vaccinated animals. Occasionally, PCV-2-SD is diagnosed in vaccinated farms. The objective of this study was to genotype the PCV-2 strains detected in vaccinated animals diagnosed with PCV-2-SD. Additionally, the evolution of the frequency of PCV-2 genotype detection at Spanish, European, and world levels was assessed. Fifty cases diagnosed as PCV-2-SD between 2009 and 2020 were included in this study. PCV-2 genotype was determined by sequencing the Cap gene region. Among them, only PCV-2b (23/50, 46%) and PCV-2d (27/50, 54%) genotypes were detected. Although the frequency of detection of these two genotypes was similar, their temporal distribution was different. Whereas most PCV-2b sequences (17/23, 74%) were detected between 2009 and 2012, PCV-2d sequences were obtained from 2013 to 2020. Indeed, a predominance of the PCV-2d genotype was observed from 2013 onwards, a trend also noticed at European and world levels. The results suggest that detection of particular genotypes in vaccinated animals probably reflects the general prevalence of the genotypes over time rather than genotype-specific vaccine-immunity escaping.
Highlights
Porcine circovirus 2 (PCV-2) is the main causative agent of a group of diseases known as porcine circovirus associated diseases (PCVD) which include porcine circovirus 2 (PCV-2) systemic disease (PCV-2-SD), porcine dermatitis and nephropathy (PDNS), PCV-2 reproductive disease (PCV-2-RD), and PCV-2 subclinical infection (PCV-2-SI) [1]
Vaccination against PCV-2 has drastically reduced the impact of PCVDs, diagnosis of PCV-2-SD is still established occasionally
Diagnostic criteria for PCV-2-SD include the presence of clinical signs compatible with the disease and the observation of characteristic histologic lesions in lymphoid tissues, together with the detection of moderate to marked amount of PCV-2 in damaged tissues [3]
Summary
PCV-2-SD and PCV-2-SI are the most economically important among them [2]. Vaccination against PCV-2 has drastically reduced the impact of PCVDs, diagnosis of PCV-2-SD is still established occasionally. Diagnostic criteria for PCV-2-SD include the presence of clinical signs compatible with the disease (growth retardation, wasting, and respiratory and/or digestive clinical 4.0/). Signs) and the observation of characteristic histologic lesions in lymphoid tissues (lymphocyte depletion [LD], histiocytic infiltration [HI], and presence of multinucleated cells and/or intracytoplasmic inclusions), together with the detection of moderate to marked amount of PCV-2 in damaged tissues [3]. PCV-2a, PCV-2b, and PCV-2d show a global distribution and are considered the most prevalent ones [6]. The PCV-2 genotype global prevalence is considered rather dynamic. In 1996, the most frequent genotype in pigs was PCV-2a, but in 2000–2004, a global genotype shift from PCV-2a to PCV-2b occurred [7,8,9,10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
