Molecular detection and phylogenetic analysis of porcine circovirus type 3 in 21 Provinces of China during 2015–2017

Abstract

Summary The emerging Porcine circovirus type 3 (PCV3) is associated with porcine dermatitis and nephropathy syndrome, reproductive failure and cardiac and multisystemic inflammation. To trace the prevalence and evolution of PCV3 in pigs with respiratory diseases or digestive diseases in China, 616 samples were collected from 21 provinces or municipalities of China from 2015 to 2017. All samples were analysed with PCR and a cap‐gene‐based phylogeny. The results indicated that the positive rate of PCV3 was 12.2% (75/616) at the sample level; 24.1% (42/174) at the farm level; 10.4% (50/480) in the digestive‐disease‐affected samples; 26.6% (25/94) in the respiratory‐disease‐affected samples; all 42 healthy samples were negative for PCV3. A statistical analysis showed that PCV3 infection was closely associated with both digestive diseases (p < 0.05) and respiratory diseases (p < 0.01). A sequence analysis revealed that the cap genes of the 51 PCV3 strains identified in our study shared nucleotide homologies of 97.2%–100% and amino acid homologies of 96.3%–100%. A total of 17 amino acid mutations were observed among the Cap proteins of the 51 PCV3 strains, of which R10/K, A24/V, R27/K, T77/S, F104/Y, I150/L are mutations among worldwide strains. A phylogenetic analysis demonstrated that the 51 PCV3 strains formed three clades, including PCV3a (15/51, 29.4%), PCV3b (21/51, 41.2%) and PCV3c (15/51, 29.4%). These data provide evidence that PCV3 exhibits high prevalence and genetic diversity and is associated with digestive diseases and respiratory diseases in pig.

Similar frequency of Porcine circovirus 3 (PCV‐3) detection in serum samples of pigs affected by digestive or respiratory disorders and age‐matched clinically healthy pigs

“…In contrast to the two previous studies evaluating such putative relationship (Qi et al, ; Zhai et al, ), no significant differences in terms of PCV‐3 DNA frequency detection were found among pigs with respiratory or digestive disorders compared between them or with age‐matched healthy animals. The previously mentioned studies referred to samples from China and used either serum (Zhai et al, ) as in the present work or intestinal/lung tissues (Qi et al, ), collected based exclusively in the animals showing clinical signs.…”

“…At the same time, PCV‐3 was detected in sows displaying reproductive problems, increased mortality rate, and suffering from respiratory disorders and porcine dermatitis and nephropathy syndrome (PDNS) (Palinski et al, ). Since the very first description of PCV‐3, this virus has been found in pigs with respiratory clinical signs and lung lesions (Kedkovid et al, ; Qi et al, ; Shen et al, ; Zhai et al, ), digestive disorders (Qi et al, ; Zhai et al, ), congenital tremors (Shen et al, ), rectal prolapse (Phan et al, ) and periweaning failure‐to‐thrive syndrome (Franzo, Kekarainen, Llorens, Correa‐Fiz, & Segalés, ). However, several of these studies where PCV‐3 was found in diseased animals failed to provide healthy age‐matched pigs as control groups (Kedkovid et al, ; Palinski et al, ; Phan et al, ; Shen et al, ).…”

“…The apparent most consistent relationship of this novel virus with disease occurrence is regarding respiratory and digestive disorders. Two studies found PCV‐3 DNA in pigs with severe and/or mild respiratory disease compared to healthy animals, pointing out to a potential involvement of this virus in disease causation (Qi et al, ; Zhai et al, ). Same studies also suggested a putative association with digestive disorders based on the higher frequency of detection of the virus DNA in diseased animals compared to healthy ones (Qi et al, ; Zhai et al, ).…”

An epidemiological investigation of porcine circovirus 3 infection in dogs in the Guangxi Province from 2015 to 2017, China

“…Consistent with previous reports, there are six variant sequences of amino acids 24 to 27 of the Cap . Several studies suggest that these four amino acids are associated with genetic variation and evolution of PCV3 (Ha et al, 2018;Qi et al, 2019). In addition, we also found mutations in other amino acids of the Cap (D124 to N124 and G160 to R160).…”

“…Subsequently, this virus has been detected in many countries and has an abnormally high positive rate (Costa et al, 2014;Deim et al, 2019;Faccini et al, 2017;Saraiva et al, 2019). In China, multiple epidemiological surveillance data indicated that this virus was extensively prevalent in pigs in many provinces and specific cities (Qi et al, 2019;Sun et al, 2018). Multiple studies have revealed that the virus was associated with several diseases (such as PDNS, multisystemic inflammation, reproductive failure) and coinfects with other viruses (for example, Torque teno sus virus, PCV2, porcine reproductive and respiratory syndrome virus) Ha et al, 2018;Wen et al, 2018).…”