Epidemiological Analysis From 2018 to 2020 in China and Prevention Strategy of Porcine Circovirus Type 2

Huang, Ying; Chen, Xianghong; Long, Yunzhi; Liu, Yang; Song, Wenbo; Liu, Jinjin; Li, Qianqian; Gong, Lei; Yu, Daobing; Huang, Chao; Tang, Xibiao

doi:10.3389/fvets.2021.753297

Cited by 12 publications

(12 citation statements)

References 36 publications

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“…According to previous reports, there have been many PCV2 genotypes in China, with PCV2a, PCV2b, and PCV2d as the predominant genotypes ( Guo et al, 2010 ; Zhao et al, 2010 ; Wei et al, 2012 ; Huang et al, 2021 ). However, the new gene cluster PCV2c must be noted by the industry.…”

Section: Discussionmentioning

confidence: 99%

Pathogenic ecological characteristics of PCV2 in large-scale pig farms in China affected by African swine fever in the surroundings from 2018 to 2021

Liu

Tong

et al. 2023

Front. Microbiol.

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Porcine circovirus type 2 (PCV2) has been identified as the causal agent of postweaning multisystemic wasting syndrome (PMWS), an economically important multifactorial disease of the swine industry worldwide. This research designed a dual nested polymerase chain reaction (PCR) detection method to simultaneously monitor porcine circovirus type 2 (PCV2) and PCV3. The limit of detection (LoD) of sensitivity for PCV2 and PCV3 was ten copies/mL for both viruses. There was no cross-reaction with any other porcine pathogens tested and no non-specific amplification. The coincidence and repetition rates were both 100%. Through the systematic and clinical sampling, 15,130 samples collected from 30 large-scale pig farms in eight provinces in China (including Hubei, Hunan, Henan, Jiangxi, Shanxi, Guangdong, Hainan, and Heilongjiang) were subjected to early warning surveillance and/or clinical diagnosis. These results revealed that the overall positive rates of PCV3 and PCV2 were 0 and 28.29%, respectively, with the lowest level recorded in Jiangxi province. The highest carrying rate was observed in Hainan province. Pigs at different ages displayed varying carrying rates for PCV: fattening pigs and gilts had the highest and the lowest carrying rates for PCV, respectively. In addition, the excretion rates for PCV of colostrum, semen, and nasal, anal, and vulval swabs were tested. The colostrum, anal swabs, and semen had higher excretion rates for PCV; these were followed by the vulval and nasal swabs that had excretion rates for PCV. Furthermore, a high blood virus-carrying rate was detected in moribund pigs, especially in pigs with fever and red skin. As to the virus-carrying rate in the pig organs received from clinical necropsy, the highest rate was found in placental tissue, followed by the kidneys, and the virus also was detected in lymphoid organs, liver, stomach, and intestines. The PCV2-positive samples were sequenced to reveal the molecular epidemic dynamics of PCV2. The results indicated four major branches, namely, PCV2a, PCV2b, PCV2c, and PCV2d, concerning PCV2 molecular epidemiology in China, with PCV2a, PCV2b, and PCV2d dominating. In conclusion, the results obtained in this study elucidated the molecular epidemiology, transmission, and positive blood samples of PCV and provided new ideas for developing comprehensive PCV control technologies to begin eliminating the disease caused by PCV by cleaning pig farms.

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Section: Discussionmentioning

confidence: 99%

Pathogenic ecological characteristics of PCV2 in large-scale pig farms in China affected by African swine fever in the surroundings from 2018 to 2021

Liu

Tong

et al. 2023

Front. Microbiol.

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“…According to previous reports, there have been many PCV2 genotypes in China, with PCV2a, PCV2b, and PCV2d as the predominant genotypes (L. J. Guo, Lu, Wei, Huang, & Liu, 2010;Huang et al, 2021;W.-K. Wei et al, 2012;Zhao, Cheng, Zhang, Han, & Chen, 2010). However, the new gene cluster PCV2c must be noted by the industry.…”

Section: Discussionmentioning

confidence: 99%

Pathogenic Ecological Characteristics of PCV2 in Large-Scale Pig Farms in China Affected by African Swine Fever from 2018-2021

Liu

Tong

et al. 2022

Preprint

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Porcine circovirus type 2 (PCV2) has been identified as the causal agent of postweaning multisystemic wasting syndrome (PMWS), an economically important multifactorial disease of the swine industry worldwide. This research designed a dual nested polymerase chain reaction (PCR) detection method to simultaneously monitor porcine circovirus type 2 (PCV2) and PCV3. The main applications for this protocol focused on technical support for its use during early warning surveillance of PCV and its application for the investigation of pathogenic ecology for large-scale pig farms in some areas of China. Two pairs of primers were designed based on the conserved regions of both PCV2 and PCV3 strain genes included in GenBank. This resulted in a highly sensitive detection method with good specificity, which was constructed by optimizing the reaction conditions and testing for specificity, sensitivity, and coincidence rate. Next, 15,130 systematic early warning and clinical samples were assessed using the developed methods. The limit of detection (LoD) of sensitivity for PCV2 and PCV3 was ten copies/mL for both viruses. There was no cross-reaction with any other porcine pathogens tested and no non-specific amplification. The coincidence and repetition rates were 100%. Through the systematic and clinical sampling, 15,130 samples from 30 large-scale pig farms in eight provinces (Hubei, Hunan, Henan, Jiangxi, Shanxi, Guangdong, Hainan, and Heilongjiang) were subjected to early warning surveillance and/or clinical diagnosis. The results revealed that the overall positive rates of PCV3 and PCV2 were 0% and 28.29%, respectively, with the lowest level [8.31% (133/1,600)] recorded in Jiangxi province. The highest carrying rate [42.36% (762/1,799)] was observed in Hainan province. Pigs at different ages displayed varying carrying rates: fattening pigs and reserve pigs had the highest and the lowest carrying rates at 65.01% (901/1,386) and 6.87% (98/1,426), respectively. In addition, the detoxification rates of colostrum, semen, and nasal, anal, and vulval swabs were tested. The colostrum, anal swabs, and semen had higher toxicity rates of 26.65%, 25.30%, and 22.71%, respectively; these were followed by the vulval and nasal swabs that had toxicity rates of 15.47% and 12.81%, respectively. Furthermore, a high blood virus-carrying rate was detected in moribund pigs, especially in pigs with fever and red skin. As to the virus-carrying rate in the pig organs received from clinical necropsy, the highest rate was found in placental tissue, followed by the kidneys, and the virus also was detected in lymphoid organs, liver, stomach, and intestines. The PCV2-positive samples were sequenced and compared to reveal the molecular epidemic dynamics of PCV2 and disclose the genetic backgrounds of these epidemic strains in China. These results provided support for tracing the sources of virus transmission in future outbreaks. The results showed that the gene sequences of the 24 PCV2 strains tested showed 95.36 to 100% homology among the detected strains and 95.46 to 99.98% among the detected strains and the reference strains. Nine strains belonged to PCV2a, seven belonged to PCV2b, two belonged to PCV2c, and six strains belonged to PCV2d.

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“…To date, based on genomic characteristics, PCV2 strains have been divided into eight genotypes (PCV2a-h), of which multiple genotypes were prevalent in China 3,24,36,37 . More recently, PCV2d has been considered a novel emerging major genotype prevalent in Chinese pig populations 3,24,32 .…”

Section: Discussionmentioning

confidence: 99%

Prevalence and genetic diversity of porcine circovirus type 2 in Henan Province of China during 2020-2023

Peng,

Lv,

Zhang

et al. 2024

Preprint

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The genetic diversity and widespread of porcine circovirus type 2 (PCV2), mainly lead to porcine circovirus-associated diseases (PCVADs), seriously threatens the swine industry worldwide. In the present study, to investigate the recent prevalence and genetic diversity of PCV2 in Henan Province of China, a total of 385 tissue samples collected from pig farms of different sizes during 2020 and 2023 were analyzed by PCR. Overall, 71.17% (274/385) tissue samples of pigs were positive for PCV2, with the detection rates of PCV2 were 81.16% (112/138), 72.41% (84/116), 62.50% (55/88), 53.49% (23/43) in 2020, 2021, 2022, 2023, respectively, indicating the detection rates of PCV2 decreased progressively in Henan Province of China in recent years. Additionally, the complete genomes of 34 PCV2 strains were sequenced and analyzed, which indicated that their nucleotide identities were 93.9–100.0%, 96.70–100.0%, and 88.90–100.0% in the complete genome, ORF1, ORF2, respectively, and amino acid identities were 98.10–100.0% and 88.60–100.0% in the replicase and capsid proteins, respectively. Phylogenetic analysis based on the complete genome sequences and deduced amino acids of ORF2 showed that the PCV2 strains obtained in the present study could be classified into three sub-clades, with the most strains clustered into clade PCV2d, indicated PCV2d is the predominated subtype in Henan Province, China. Moreover, four substitution sites (V57I, I89R/L, P134T, D210E) were observed in PCV2b ORF2 that were absent in PCV2a and PCV2d, and 4 substitution sites (S68N, I89L, T/P134N, S169G/R) were observed in PCV2d ORF2 that were absent in PCV2a and PCV2b. In general, the present study revealed a high prevalence and high genetic divergence of PCV2 among Chinese swine herds, provided an insight into the ongoing emerged PCV2, and enriched our understanding of the genetic diversity and evolution of PCV2.

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Epidemiological Analysis From 2018 to 2020 in China and Prevention Strategy of Porcine Circovirus Type 2

Cited by 12 publications

References 36 publications

Pathogenic ecological characteristics of PCV2 in large-scale pig farms in China affected by African swine fever in the surroundings from 2018 to 2021

Pathogenic ecological characteristics of PCV2 in large-scale pig farms in China affected by African swine fever in the surroundings from 2018 to 2021

Pathogenic Ecological Characteristics of PCV2 in Large-Scale Pig Farms in China Affected by African Swine Fever from 2018-2021

Prevalence and genetic diversity of porcine circovirus type 2 in Henan Province of China during 2020-2023

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