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Kim SJ, Moon J. Narrative Review of the Safety of Using Pigs for Xenotransplantation: Characteristics and Diagnostic Methods of Vertical Transmissible Viruses. Biomedicines 2024; 12:1181. [PMID: 38927388 PMCID: PMC11200752 DOI: 10.3390/biomedicines12061181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024] Open
Abstract
Amid the deepening imbalance in the supply and demand of allogeneic organs, xenotransplantation can be a practical alternative because it makes an unlimited supply of organs possible. However, to perform xenotransplantation on patients, the source animals to be used must be free from infectious agents. This requires the breeding of animals using assisted reproductive techniques, such as somatic cell nuclear transfer, embryo transfer, and cesarean section, without colostrum derived in designated pathogen-free (DPF) facilities. Most infectious agents can be removed from animals produced via these methods, but several viruses known to pass through the placenta are not easy to remove, even with these methods. Therefore, in this narrative review, we examine the characteristics of several viruses that are important to consider in xenotransplantation due to their ability to cross the placenta, and investigate how these viruses can be detected. This review is intended to help maintain DPF facilities by preventing animals infected with the virus from entering DPF facilities and to help select pigs suitable for xenotransplantation.
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Affiliation(s)
- Su-Jin Kim
- Apures Co., Ltd., 44, Hansan-gil, Cheongbuk-eup, Pyeongtaek-si 17792, Gyeonggi-do, Republic of Korea;
| | - Joonho Moon
- Division of Cardiology, Department of Internal Medicine, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
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Otabi H, Miura H, Uryu H, Kobayashi-Harada R, Abe K, Nakano K, Umeyama K, Hasegawa K, Tsukahara T, Nagashima H, Inoue R. Development of a panel for detection of pathogens in xenotransplantation donor pigs. Xenotransplantation 2023; 30:e12825. [PMID: 37771249 DOI: 10.1111/xen.12825] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/11/2023] [Accepted: 08/29/2023] [Indexed: 09/30/2023]
Abstract
There have been high expectations in recent years of using xenotransplantation and regenerative medicine to treat humans, and pigs have been utilized as the donor model. Pigs used for these clinical applications must be microbiologically safe, that is, free of infectious pathogens, to prevent infections not only in livestock, but also in humans. Currently, however, the full spectrum of pathogens that can infect to the human host or cause disease in transplanted porcine organs/cells has not been fully defined. In the present study, we thus aimed to develop a larger panel for the detection of pathogens that could potentially infect xenotransplantation donor pigs. Our newly developed panel, which consisted of 76 highly sensitive PCR detection assays, was able to detect 41 viruses, 1 protozoa, and a broad range of bacteria (by use of universal 16S rRNA primers). The applicability of this panel was validated using blood samples from uterectomy-born piglets, and pathogens suspected to be vertically transmitted from sows to piglets were successfully detected. We estimate that, at least for viruses and bacteria, the number of target pathogens detected by the developed screening panel should suffice to meet the microbiological safety levels required worldwide for xenotransplantation and/or regenerative therapy. This panel provides greater diagnosis options to produce donor pigs so that it would render unnecessary to screen for all pathogens listed. Instead, the new panel could be utilized to detect only required pathogens within a given geographic range where the donor pigs for xenotransplantation have been and/or are being developed.
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Affiliation(s)
- Hikari Otabi
- Laboratory of Animal Science, Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Osaka, Japan
| | - Hiroto Miura
- Laboratory of Animal Science, Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Osaka, Japan
| | - Haruka Uryu
- Laboratory of Animal Science, Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Osaka, Japan
- Laboratory of Animal Science, Kyoto Prefectural University, Kyoto, Japan
| | | | - Kanako Abe
- Laboratory of Animal Science, Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Osaka, Japan
| | - Kazuaki Nakano
- Meiji University International Institute for Bio-Resource Research, Kawasaki, Japan
| | - Kazuhiro Umeyama
- Meiji University International Institute for Bio-Resource Research, Kawasaki, Japan
| | - Koki Hasegawa
- Laboratory of Medical Bioengineering, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki, Japan
| | | | - Hiroshi Nagashima
- Meiji University International Institute for Bio-Resource Research, Kawasaki, Japan
- Laboratory of Medical Bioengineering, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki, Japan
| | - Ryo Inoue
- Laboratory of Animal Science, Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Osaka, Japan
- Laboratory of Animal Science, Kyoto Prefectural University, Kyoto, Japan
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Maity HK, Samanta K, Deb R, Gupta VK. Revisiting Porcine Circovirus Infection: Recent Insights and Its Significance in the Piggery Sector. Vaccines (Basel) 2023; 11:1308. [PMID: 37631876 PMCID: PMC10457769 DOI: 10.3390/vaccines11081308] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/29/2023] [Accepted: 07/29/2023] [Indexed: 08/27/2023] Open
Abstract
Porcine circovirus (PCV), a member of the Circoviridae family within the genus Circovirus, poses a significant economic risk to the global swine industry. PCV2, which has nine identified genotypes (a-i), has emerged as the predominant genotype worldwide, particularly PCV2d. PCV2 has been commonly found in both domestic pigs and wild boars, and sporadically in non-porcine animals. The virus spreads among swine populations through horizontal and vertical transmission routes. Despite the availability of commercial vaccines for controlling porcine circovirus infections and associated diseases, the continuous genotypic shifts from a to b, and subsequently from b to d, have maintained PCV2 as a significant pathogen with substantial economic implications. This review aims to provide an updated understanding of the biology, genetic variation, distribution, and preventive strategies concerning porcine circoviruses and their associated diseases in swine.
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Affiliation(s)
- Hemanta Kumar Maity
- Department of Avian Science, Faculty of Veterinary & Animal Science, West Bengal University of Animal & Fishery Sciences, Kolkata 700037, West Bengal, India
| | - Kartik Samanta
- Department of Avian Science, Faculty of Veterinary & Animal Science, West Bengal University of Animal & Fishery Sciences, Kolkata 700037, West Bengal, India
| | - Rajib Deb
- ICAR-National Research Center on Pig, Rani, Guwahati 781131, Assam, India
| | - Vivek Kumar Gupta
- ICAR-National Research Center on Pig, Rani, Guwahati 781131, Assam, India
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Fan M, Bian L, Tian X, Hu Z, Wu W, Sun L, Yuan G, Li S, Yue L, Wang Y, Wu L, Wang Y, Yan Z, Ren J, Li X. Infection characteristics of porcine circovirus type 2 in different herds from intensive farms in China, 2022. Front Vet Sci 2023; 10:1187753. [PMID: 37397003 PMCID: PMC10311082 DOI: 10.3389/fvets.2023.1187753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 05/31/2023] [Indexed: 07/04/2023] Open
Abstract
Introduction Porcine circovirus type 2 (PCV2) is the primary etiological agent of porcine circovirus diseases (PCVD), which are widespread in most pig herds, causing huge economic losses in the global pig industry. Therefore, it is critical to assess the infection characteristics of PCV2 in different swine herds to develop effective strategies against PCVD. Methods In this study, routine diagnostic and monitoring protocols were used to collect 12,714 samples from intensive farms in China, and PCV2 was tested for by qPCR to determine positivity rates and viral loads in samples from different herds and materials. Results PCV2 was found to be prevalent throughout China, and fattening farms had higher positivity rates than breeding farms. The PCV2 positivity rates in breeding farms in Southern China were higher than those in Northern China. Growing-finishing pigs demonstrated the highest positivity rate in the tested samples, while pre-weaning piglets and adult sows had the lowest. Meanwhile, samples with viral loads exceeding 106 copies/mL in growing-finishing pigs had 27.2% positivity, compared to 1.9% and 3.3% in sows and piglets, respectively. The results of the viral loads in the serum samples followed a similar trend. Discussion The findings reveal that PCV2 circulates in different herds from intensive farms, with positivity increasing from pre-weaning to growing-finishing herds. It is urgent to develop effective strategies to reduce PCV2 positivity in growing-finishing herds and prevent viral circulation among pigs.
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Affiliation(s)
- Mingyu Fan
- Shandong New Hope Liuhe Agriculture and Animal Husbandry Technology Co., Ltd. (NHLH Academy of Swine Research), Dezhou, China
- Shandong Swine Health Data and Intelligent Monitoring Project Laboratory, Dezhou University, Dezhou, China
| | - Lujie Bian
- Shandong New Hope Liuhe Agriculture and Animal Husbandry Technology Co., Ltd. (NHLH Academy of Swine Research), Dezhou, China
| | - Xiaogang Tian
- Shandong New Hope Liuhe Agriculture and Animal Husbandry Technology Co., Ltd. (NHLH Academy of Swine Research), Dezhou, China
| | - Zhiqiang Hu
- Shandong New Hope Liuhe Agriculture and Animal Husbandry Technology Co., Ltd. (NHLH Academy of Swine Research), Dezhou, China
| | - Weisheng Wu
- Xiajin New Hope Liuhe Agriculture and Animal Husbandry Co., Ltd., Dezhou, China
| | - Leilei Sun
- New Hope Liuhe Co., Ltd., Chengdu, China
| | | | | | - Lei Yue
- New Hope Liuhe Co., Ltd., Chengdu, China
| | - Ying Wang
- New Hope Liuhe Co., Ltd., Chengdu, China
| | - Lili Wu
- Shandong New Hope Liuhe Agriculture and Animal Husbandry Technology Co., Ltd. (NHLH Academy of Swine Research), Dezhou, China
| | - Yongquan Wang
- Xiajin New Hope Liuhe Agriculture and Animal Husbandry Co., Ltd., Dezhou, China
| | - Zheng Yan
- New Hope Liuhe Co., Ltd., Chengdu, China
| | - Jing Ren
- Shandong Swine Health Data and Intelligent Monitoring Project Laboratory, Dezhou University, Dezhou, China
| | - Xiaowen Li
- Shandong New Hope Liuhe Agriculture and Animal Husbandry Technology Co., Ltd. (NHLH Academy of Swine Research), Dezhou, China
- Shandong Swine Health Data and Intelligent Monitoring Project Laboratory, Dezhou University, Dezhou, China
- Xiajin New Hope Liuhe Agriculture and Animal Husbandry Co., Ltd., Dezhou, China
- New Hope Liuhe Co., Ltd., Chengdu, China
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Sirisereewan C, Thanawongnuwech R, Kedkovid R. Current Understanding of the Pathogenesis of Porcine Circovirus 3. Pathogens 2022; 11:pathogens11010064. [PMID: 35056012 PMCID: PMC8778431 DOI: 10.3390/pathogens11010064] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 02/07/2023] Open
Abstract
Circoviruses are closed, circular, single-stranded DNA viruses belonging to the family Circoviridae and the genus Circovirus. To date, at least four porcine circoviruses (PCVs) have been recognized, including PCV1 to PCV4, respectively. Similar to PCV2 pathogenesis, PCV3 has been reported worldwide with myriad clinical and pathological presentations such as reproductive disorders, respiratory diseases, diarrhea etc. Current understanding of PCV3 pathogenesis is very limited since the majority of studies were mostly field observations. Interpretation of the results from such studies is not always simple. Various confounding factors affect the clinical appearance and pathological changes of the infected pigs. Recently, several experimental PCV3 infection studies have been reported, providing a better understanding of its pathogenesis. In this review, we focused on novel findings regarding PCV3 pathogenesis from both field observation and experimental infection studies. Possible factors involved in the conflicting results among the experimental infection studies are also discussed. This review article provides important insight into the current knowledge on PCV3 pathogenesis which would aid in prioritizing research in order to fill the knowledge gaps.
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Affiliation(s)
- Chaitawat Sirisereewan
- Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand;
| | - Roongroje Thanawongnuwech
- Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand;
- Correspondence: (R.T.); (R.K.)
| | - Roongtham Kedkovid
- Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
- Swine Reproduction Research Unit, Chulalongkorn University, Bangkok 10330, Thailand
- Correspondence: (R.T.); (R.K.)
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Evidence of porcine circovirus type 2 and co-infection with ungulate protoparvovirus 1 (porcine parvovirus) in mummies and stillborn piglets in subclinically infected farm. INFECTION GENETICS AND EVOLUTION 2021; 89:104735. [PMID: 33516972 DOI: 10.1016/j.meegid.2021.104735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 12/24/2020] [Accepted: 01/22/2021] [Indexed: 11/23/2022]
Abstract
Porcine circovirus type 2 (PCV2) and protoparvovirus 1 (PPV) were detected as single infection (6/131) and (11/131) respectively, or co-infection (6/131) in fetuses and stillborn piglets from normal deliveries in a farm without reproductive problems. Twenty in twenty-three positive samples were over 70 days of gestation, which is when the fetus becomes immunocompetent, and the presence of a NADL-2 PPV strain suggests fetal immune system impairment. Phylogenetic analysis of sequences obtained showed that 8/9 sequences are related to cluster 13 and the remaining is grouped into cluster 11 sequences. An increase in variability in ORF2 sequences in Argentina was observed. It is not clear whether the detection of fetuses positive to PPV and PCV2 is of epidemiological importance in a subclinically affected farm. However, the results of this study showed that currently used vaccines and vaccine protocols do not fully protect against PPV or PCV2 fetus infection.
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Yuan AW, Pang P, Gong QL, Deng ZB. Germocyte lesions caused by porcine circovirus type 2b in Kunming mice. Pol J Vet Sci 2017; 20:25-29. [PMID: 28525333 DOI: 10.1515/pjvs-2017-0004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Porcine circovirus type 2 (PCV2) has been known as a causative agent of reproductive failure in the sow. In the present study mouse model was used to investigate PCV2 infection. In order to investigate whether PCV2 can induce lesions of spermatocytes and oocytes, 6 male and 6 female mice were each inoculated intraperitoneally with PCV2b, and 3 male and 3 female mice mock-infected with cell culture supernatant served as controls. Samples of testes and ovaries from PCV2b-inoculated and mock-infected mice were investigated using PCR, histopathological, ultrastructural and immunofluorescent histochemical methods at 14 and 21 day post infection (dpi). The study revealed that in the virus-inoculated mice leydig cells in testes and granulosa cells in ovaries were degenerated, and a small number of spermatocytes and oocytes showed apoptosis. Positive PCV2b antigen signals were also observed in these apoptotic cells. It can be suggested that PCV2 can cause lesions of spermatocyte and oocyte prior to zygotes formation in its host.
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Dong WN, Jun LJ, Bing WA, Zhe Z, Yan C, Yu M, Yang Z, Feng WZ, Bang DZ. Vertical Transmission of PCV2b to Fetuses in Sows Intramuscularly Infected with PCV2b. Pol J Vet Sci 2017; 19:471-476. [PMID: 27760027 DOI: 10.1515/pjvs-2016-0059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In order to investigate whether PCV2b can be transmitted across the placenta in sows thereby causing vertical infection of fetuses, six sows in 75 day of pregnancy were either intramuscularly inoculated with a PCV2b culture supernatant (n = 4) or mock infected with cell culture supernatant (n = 2). At parturition, 3 newborn piglets from each litter were randomly selected and euthanatized prior to suckling. Samples of the mesenteric lymph nodes, spleens, kidneys, hearts and lungs were collected for PCR, histopathological and immunohistochemical assays. The results showed that the newborn piglets from PCV2b-infected sows had histopathological lesions in the tested tissues. Moreover, PCV2b antigen and DNA were detected as well. These findings therefore suggested that porcine circovirus type 2b can be transmitted across the placenta of sows, thereby leading to PCV2b vertical infection of the fetuses.
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Abstract
The present study was performed to determine the expression of porcine circovirus type 2
(PCV2) antigen in the ovarian tissue of naturally infected gilts. Ovarian tissues were
obtained from 11 culled gilts. The ovarian tissues sections were divided into two groups
according to PCV2 DNA detection using PCR. PCV2 antigen was assessed in the paraffin
embedded ovarian tissue sections by immunohistochemistry. A total of 2,131 ovarian
follicles (i.e., 1,437 primordial, 133 primary, 353 secondary and 208 antral follicles),
66 atretic follicles and 131 corpora lutea were evaluated. It was found that PCV2 antigen
was detected in 280 ovarian follicles (i.e., 239 primordial follicles, 12 primary
follicles, 10 secondary follicles and 19 antral follicles), 1 atretic follicles and 3
corpora lutea (P<0.05). PCV2 antigen was detected in primordial
follicles more often than in secondary follicles, atretic follicles and corpora lutea
(P<0.05). The detection of PCV2 antigen was found mainly in oocytes.
PCV2 antigen was found in both PCV2 DNA positive and negative ovarian tissues. It can be
concluded that PCV2 antigen is expressed in all types of the ovarian follicles and corpora
lutea. Further studies should be carried out to determine the influence of PCV2 on porcine
ovarian function and oocyte quality.
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Affiliation(s)
- Padet Tummaruk
- Department of Obstetrics, Gynaecology and Reproduction, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
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Galeati G, Zannoni A, Spinaci M, Bucci D, Ostanello F, Panarese S, Tamanini C, Sarli G. Porcine circovirus type 2 detection inin vitroproduced porcine blastocysts after virus sperm exposure. Anim Sci J 2015; 87:511-6. [DOI: 10.1111/asj.12465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 04/09/2015] [Accepted: 04/27/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Giovanna Galeati
- Department of Veterinary Medical Sciences; University of Bologna; Bologna Italy
| | - Augusta Zannoni
- Department of Veterinary Medical Sciences; University of Bologna; Bologna Italy
| | - Marcella Spinaci
- Department of Veterinary Medical Sciences; University of Bologna; Bologna Italy
| | - Diego Bucci
- Department of Veterinary Medical Sciences; University of Bologna; Bologna Italy
| | - Fabio Ostanello
- Department of Veterinary Medical Sciences; University of Bologna; Bologna Italy
| | - Serena Panarese
- Department of Veterinary Medical Sciences; University of Bologna; Bologna Italy
| | - Carlo Tamanini
- Department of Veterinary Medical Sciences; University of Bologna; Bologna Italy
| | - Giuseppe Sarli
- Department of Veterinary Medical Sciences; University of Bologna; Bologna Italy
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Prevalence of porcine circovirus-2 DNA-positive ovarian and uterine tissues in gilts culled due to reproductive disturbance in Thailand. Trop Anim Health Prod 2015; 47:833-40. [PMID: 25782565 DOI: 10.1007/s11250-015-0796-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/08/2015] [Indexed: 10/23/2022]
Abstract
The present study aimed to determine the prevalence of porcine circovirus-2 (PCV-2) DNA-positive ovarian and uterine tissues in gilts culled due to reproductive disturbance in Thailand. Tissues (70 ovaries and 102 uteri) and serum (n = 102) samples from 102 gilts were included. PCV-2 DNA was detected by using polymerase chain reactions. The localisation of PCV-2 antigen was determined by immunohistochemistry, and PCV-2 antibody was evaluated by ELISA. PCV-2 DNA was detected in 30.0 % (21/70) of the ovaries and in 45.1 % (46/102) of the uteri. Age did not influence the frequency of PCV-2 DNA detection in these reproductive organs of gilts (P > 0.05). The prevalence of PCV-2 DNA-positive uterine tissue in gilts culled due to non-reproductive problems (20.0 %) was lower than gilts culled due to abortion (85.0 %), abnormal vaginal discharge (47.5 %) and anoestrus (53.5 %) (P < 0.05). The prevalence of PCV-2 DNA-positive uterine tissue in the gilts with high antibody titres (23.0 %) was lower than in gilts with low antibody titres (57.6 %) and seronegative gilts (64.5 %) (P < 0.05). PCV-2 immunostaining was detected in the endometrial cells, lymphocytes and macrophages of the uteri and in oocytes and granulosa cells of the ovaries. In conclusion, the detection of PCV-2 in the reproductive organs reveals an important potential impact of this virus on the reproductive apparatus in gilts.
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Saha D, Karniychuk UU, Huang L, Geldhof M, Vanhee M, Lefebvre DJ, Meerts P, Ducatelle R, Doorsselaere JV, Nauwynck HJ. Unusual outcome of in utero infection and subsequent postnatal super-infection with different PCV2b strains. Virol Sin 2014; 29:176-82. [PMID: 24950783 DOI: 10.1007/s12250-014-3431-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 06/05/2014] [Indexed: 10/25/2022] Open
Abstract
VC2002, isolated from postweaning multisystemic wasting syndrome (PMWS)-affected pig, is a mixture of two porcine circovirus genotype 2b (PCV2b) viruses, K2 and K39. Preliminary experiments disclosed short-term adverse effects of K39, but not K2, on porcine foetuses. These findings led to the hypothesis that infection of immuno-incompetent foetuses with K2 confers a status of immunotolerance, and postnatal super-infection with K39 triggers PMWS. To explore this hypothesis, nine 55-day-old foetuses were inoculated in utero (three with K2-10(4.3)TCID50, three with K39-10(4.3)TCID50 and three with medium), and foeto-pathogenicity examined. At 21 days post-inoculation (dpi), K2 did not induce pathology, whereas pathological effects of K39 were evident. Twenty-four 45-day-old foetuses were subsequently inoculated to examine the long-term effect of K2, including six with K2-high dose-10(4.3)TCID50, six with K2-low dose-10(2.3)TCID50 and 12 mock-inoculated controls. Both doses resulted in five mummified foetuses and one live-born piglet each (69dpi). K2 was recovered from all mummies. K2 and K2-specific antibodies were not detected in serum of the two live-born piglets at birth, indicating full control of K2 infection. The K2-low dose-infected piglet was immunostimulated at day 2, but not the K2-high dose-infected piglet. Both non-stimulated and stimulated K2-infected piglets were super-inoculated with K39 at day 6 or 8 (taken as 0 days post super-inoculation). Low viral replication was observed in the non-stimulated K2-K39 piglet (up to 10(3.3)TCID50/g; identified as K39). In contrast, viral replication was extremely high in the stimulated K2-K39 piglet (up to 10(5.6)TCID50/g) and identified as K2, indicating that K2 infection is controlled during foetal life, but emerges after birth upon immunostimulation. However, none of the piglets showed any signs of PMWS.
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Affiliation(s)
- Dipongkor Saha
- Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
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