Porcine Circovirus 2 Replication in Colostrum‐deprived Piglets Following Experimental Infection and Immune Stimulation Using A Modified Live Vaccine against Porcine Respiratory and Reproductive Syndrome Virus

Allan, Gordon; Caprioli, Andrea; McNair, I.; Lagan-Tregaskis, P.; Ellis, John; Krakowka, Steven; McKillen, John; Ostanello, Fabio; McNeilly, F.

doi:10.1111/j.1863-2378.2007.01041.x

Cited by 24 publications

(15 citation statements)

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“…Previous experimental studies documenting interactions between the PRRS MLV and PCV2 infection have yielded conflicting results. Allan et al (35) found that colostrum-deprived, specificpathogen-free (SPF) pigs infected with PCV2 at the age of 5 weeks and administered the PRRS MLV 1 week later had greater amounts of PCV2 antigen in tissues and more-severe histologic lesions, characteristic of PMWS, than pigs infected with PCV2 alone. However, the pigs failed to exhibit clinical signs or gross lesions typical of PCVAD (35).…”

Section: Discussionmentioning

confidence: 99%

“…Allan et al (35) found that colostrum-deprived, specificpathogen-free (SPF) pigs infected with PCV2 at the age of 5 weeks and administered the PRRS MLV 1 week later had greater amounts of PCV2 antigen in tissues and more-severe histologic lesions, characteristic of PMWS, than pigs infected with PCV2 alone. However, the pigs failed to exhibit clinical signs or gross lesions typical of PCVAD (35). In contrast, Opriessnig et al (36) evaluated the effects of PCV2 infection on the efficacy of the PRRS MLV in groups of 10 early-weaned SPF pigs.…”

Section: Discussionmentioning

confidence: 99%

“…At 28 days postvaccination (dpv), all pigs in both rooms were challenged with a combination of PRRSV and PCV2b. Individual body weights were determined on days Ϫ3, 0, 7,14,21,28,35,42,49,56,63, and 70 postvaccination. Blood samples were collected from all pigs at 0, 4, 7, 11, 14, 21, 28, 35, and 42 days postinfection (dpi).…”

Section: Methodsmentioning

confidence: 99%

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Vaccination with a Porcine Reproductive and Respiratory Syndrome (PRRS) Modified Live Virus Vaccine Followed by Challenge with PRRS Virus and Porcine Circovirus Type 2 (PCV2) Protects against PRRS but Enhances PCV2 Replication and Pathogenesis Compared to Results for Nonvaccinated Cochallenged Controls

Niederwerder

Bawa

Serão

et al. 2015

Clin. Vaccine Immunol.

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cCoinfections involving porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) contribute to a group of disease syndromes known as porcine circovirus-associated disease (PCVAD). Presumably, PRRSV infection enhances PCV2 replication as a result of modulation of host immunity. The purpose of this study was to evaluate PCV2 replication and pathogenesis in pigs vaccinated with a PRRS modified live virus (MLV) vaccine and subsequently challenged with a combination of PRRSV and PCV2. During the early postchallenge period, the number of pigs with PRRSV-associated clinical signs was decreased, and average daily gain (ADG) was increased, in the vaccinated group, demonstrating the protective effect of PRRS vaccination. However, during the later postchallenge period, more pigs in the vaccinated group showed increased PCV2 viremia, decreased ADG, increased PCVAD clinical signs, and increased mortality. In this disease model, the early benefits of PRRSV vaccination were outweighed by the later amplification of PCVAD. P orcine circovirus type 2 (PCV2), a single-stranded DNA virus in the family Circoviridae, contributes to a group of syndromes collectively termed porcine circovirus-associated disease (PCVAD) (1). Two important clinical syndromes associated with PCVAD are PCV2-associated pneumonia and postweaning multisystemic wasting syndrome (PMWS) (1, 2). Management of PCV2 through the use of inactivated and subunit vaccines has led to the effective control of PCVAD in North America and Europe. However, the emergence of new PCV2 strains and the lack of PCV2 vaccination programs in other countries create an uncertain future for continued disease control.Porcine reproductive and respiratory syndrome virus (PRRSV) is a single-stranded RNA virus in the family Arteriviridae (3, 4). For the past 20 years, PRRSV has remained the most costly disease affecting swine production worldwide (5). PRRSV infection contributes to a number of immunological outcomes that increase the susceptibility of the host to secondary infections by primary and secondary pathogens (6-8). PRRSV is frequently isolated along with PCV2 (9) and is one of the major cofactors linked with increasing PCV2 replication and pathogenesis (10-12). Previous work by us and others has shown that a principal contribution of PRRSV is to increase PCV2 viremia (13). Increased PCV2 replication is likely the result of immune stimulation that results in more PCV2-permissive cells combined with PRRSV-induced immunomodulation. The complex etiology of PCVAD, including the role of PRRSV infection, has yet to be fully understood. In an extensive body of work, we identified the aberrant recognition of a nonneutralizing decoy epitope on the PCV2 capsid protein (CP) as a contributing factor in PCVAD immunopathogenesis. Natural PCV2 infection of a population produces a mixture of pigs that recognize the decoy and neutralizing epitopes, which may explain why only a subpopulation of infected pigs goes on to develop PCVAD (13-15).In this study, we to...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Vaccination with a Porcine Reproductive and Respiratory Syndrome (PRRS) Modified Live Virus Vaccine Followed by Challenge with PRRS Virus and Porcine Circovirus Type 2 (PCV2) Protects against PRRS but Enhances PCV2 Replication and Pathogenesis Compared to Results for Nonvaccinated Cochallenged Controls

Niederwerder

Bawa

Serão

et al. 2015

Clin. Vaccine Immunol.

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“…The early vaccination of piglets versus Mycoplasma hyopneumoniae was cited in certain trials (Allan et al., 2001; Kyriakis et al., 2002). Recently, using colostrum‐deprived piglets that were being vaccinated with a PRRS‐modified live vaccine and then infected with PCV2, the microscopical lesions and the PVC2‐antigen load associated to the lesions, were found to be higher in the vaccinated pigs (Allan et al., 2007b). But no clinical PMWS was obtained, and no typical macroscopic lesions, either.…”

Section: Pathogenesismentioning

confidence: 99%

Post-Weaning Multisystemic Wasting Syndrome and Other PCV2-Related Problems in Pigs: a 12-Year Experience

Madec

Rose

Grasland

et al. 2008

Transboundary and Emerging Diseases

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Summary Post‐weaning multisystemic wasting syndrome (PMWS) and other porcine circovirus type 2 (PCV2)‐related diseases have been reported throughout the world for about 10 years. The present paper reviews the knowledge acquired in different fields and is largely based on the authors’ experience. The horizontal transmission of PCV2 is widely documented. Contact between pigs is the main route of transmission for both PCV2 and PMWS. However, experimental inoculation of PCV2 to pigs does not give consistent results and severe clinical signs as encountered in the field are rarely obtained. It is thus acknowledged that additional conditions are required for the disease to be severe in growing pigs. These are not all known but co‐infections are thought to act as triggers. The spread of such triggers/enhancers, which may or may not be infectious, could have played a role in PMWS dissemination via normal national and international trade, in some cases conferring an epidemic pattern to this spread. Most of the risk factors identified in surveys relate to poor biosecurity and inadequate hygiene/husbandry/herd management. The good correlation between viral burden in the tissues and disease severity emphasized the role of infection pressure. Genomic analysis showed great similarities between PCV2 isolates. However, although two main genotypes (genogroups) could be distinguished from the phylogenic trees, and changes with time, no clear relationship with strain virulence was apparent. Isolates detected in PMWS‐positive pigs could also be detected in healthy pigs from healthy farms. A strong sow effect was observed in disease expression in the offspring. Colostrum composition and colostrum intake are supposed to be key components of disease expression. Medication is relatively inefficient as a control measure. Commercial PCV2 vaccines are now becoming available. However, losses as a result of PMWS and PCV2‐related diseases are greatly reduced by applying appropriate hygiene and husbandry practices.

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“…Experimental infection of colostrum-deprived pigs demonstrated shedding of PCV2a DNA in feces, nasal, oropharyngeal and tonsillar secretions as early as one day post inoculation (dpi) [2, 6, 43]. Viremia, nasal, oropharyngeal, and fecal shedding of PCV2a DNA has been reported to persist at least 70 days in colostrum-deprived pigs [43].…”

Section: Introductionmentioning

confidence: 99%

Porcine circovirus type 2 (PCV2)-infection and re-inoculation with homologous or heterologous strains: virological, serological, pathological and clinical effects in growing pigs

et al. 2010

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Long-term PCV2 infection and/or concurrent infection with genotypes PCV2a and PCV2b may play a role in the development of clinical porcine circovirus-associated disease (PCVAD). To evaluate this premise, 24 11-week-old specific pathogen-free (SPF) pigs were randomly assigned to 1 of 4 treatments: negative controls, a single inoculation with PCV2a, single inoculation followed by re-inoculation with a homologous PCV2a strain, or repeated inoculations with heterologous strains (PCV2a, PCV2b). Pigs were evaluated for clinical signs daily through 140 days post inoculation (dpi). Serum samples were collected every other day from dpi 0 through 14 and weekly thereafter. PCV2-inoculated pigs were viremic by dpi 2 and 13 of 18 pigs remained viremic at 140 dpi. No statistical differences in the onset, level, or duration of PCV2 viremia were detected among treatment groups. Anti-PCV2 antibodies were detected between 14 and 28 dpi and were present through 140 dpi without statistical differences in antibody response among treatment groups. In the current study, pigs had extended viremia combined with detectable tissue PCV2 antigen levels despite the presence of high levels of anti-PCV2 antibody; however, no clinical disease was observed.

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Porcine Circovirus 2 Replication in Colostrum‐deprived Piglets Following Experimental Infection and Immune Stimulation Using A Modified Live Vaccine against Porcine Respiratory and Reproductive Syndrome Virus

Cited by 24 publications

References 25 publications

Post-Weaning Multisystemic Wasting Syndrome and Other PCV2-Related Problems in Pigs: a 12-Year Experience

Porcine circovirus type 2 (PCV2)-infection and re-inoculation with homologous or heterologous strains: virological, serological, pathological and clinical effects in growing pigs

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