Wide Range of the Prevalence and Viral Loads of Porcine Circovirus Type 3 (PCV3) in Different Clinical Materials from 21 Polish Pig Farms

Abstract

Porcine circovirus type 3 (PCV3) was described in different clinical cases and healthy pigs. However, little is known about its circulation in pig farms. In order to assess PCV3 prevalence in 21 Polish farms, serum, feces, and oral fluid samples were examined by quantitative real-time PCR. In total, 1451 pairs of serum and feces from the same animals, as well as 327 samples of oral fluids were analyzed. The results showed that PCV3 is more commonly detected in oral fluids (37.3% positives) than in serum (9.7% positives) or feces (15.0% positives) samples. The viral loads detected in these materials ranged from 102.5–107.2 genome equivalent copies/mL. Although in most farms PCV3 was detected post weaning, in nine farms, the virus was also found in groups of suckling piglets, and in six of them viremia was detected. In four farms with reproductive failure, fetal materials were also obtained. PCV3 was detected in 36.0% of fetuses or stillborn piglets (9/25) with viral loads of 103.1–1010.4 genome equivalent copies/mL. In summary, the virus circulation may show different patterns, and congenital or early infection is not uncommon. Precise quantification of PCV3 loads in clinical materials seems to be necessary for the study and diagnosis of the infection.

Detection and characterisation of porcine circoviruses in wild boars in northeastern Serbia

“…Adult wild boars are more often PCV3-positive than younger animals, however, our study shows no specific correlation concerning adults (Klaumann et al 2019). Different PCV3 circulation patterns, along with the limited sampling area and a relatively low sample number, might all have affected the results of our examination, suggesting a possibility of a false-negative PCV3 prevalence in the examined wild boar population (Tan et al 2020;Wozniak et al 2020). Nevertheless, the detected high PCV2 infection frequency suggests, that wild animals might serve as a disease reservoir (Turcitu et al 2011;Fabisiak et al 2012).…”

Current Understanding of the Pathogenesis of Porcine Circovirus 3

“…After the PCV3 inoculation in all studies, viremia was identified in all pigs except for pigs of Study D. In Study A (PDNS-like disease), PCV3 titers were already high in the sera at 7 dpi (6-7 log10 copies/mL) and the titers peaked at 8.89 log10 copies/mL at around 21 dpi. This viremia level could be considered high when compared with PCV3 titers from previous studies, which generally did not exceed 8 log10 copies/mL [11,44,45]. In Study B (subclinical infection), PCV3 titers started to increase during 7-14 dpi.…”

Molecular‐based detection, genetic characterization and phylogenetic analysis of porcine circovirus 4 from Korean domestic swine farms

“…This finding is similar to PCV2 and PCV3 infections that were found in pigs with different clinical presentations (Segales, 2012; Zhai et al., 2017). Because of that feature, measuring viral loads has been proposed as an important criterion to form a solid evidence base for tracking the clinical manifestations of PCV2 and PCV3 infections (Brunborg et al., 2004; Wozniak et al., 2020). As a result, this study measured the PCV4 titre and found a moderate viral load (hundred millions copies/g of tissue, Figure S1) as compared to billions copies/g of tissue as reported previously (Wozniak et al., 2020).…”