Activation of the Immune System is the Pivotal Event in the Production of Wasting Disease in Pigs Infected with Porcine Circovirus-2 (PCV-2)

Krakowka, Steven; Ellis, John; McNeilly, F.; Ringler, Susan S.; Rings, D. Michael; Allan, Gordon

doi:10.1354/vp.38-1-31

Cited by 250 publications

(245 citation statements)

References 19 publications

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“…These other factors seem to play an important role in the development of PMWS in pigs [3,12] and this effect cannot be discounted for non-porcine species.…”

Section: Discussionmentioning

confidence: 98%

Experimental inoculation of porcine circoviruses type 1 (PCV1) and type 2 (PCV2) in rabbits and mice

Quintana

Balasch²,

Segalés

et al. 2002

Vet. Res.

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-The objective of this work was to investigate the susceptibility of rabbits and mice experimentally inoculated with porcine circoviruses type 1 (PCV1) and type 2 (PCV2) to infection and development of disease and/or lesions. Forty six New Zealand rabbits and 50 ICR-CD1 mice were both divided into two groups comprising PCV1 and PCV2 inoculated animals, and a third group inoculated with non-infected cell culture medium. Rabbits were inoculated intranasally while mice were inoculated intraperitoneally. Clinical signs and body weights were recorded at the start of the experiment and at necropsy. Animals were bled, euthanised and necropsied at days 0, 3, 7, 10, 14 and 20 post-inoculation and samples were collected for histopathological, serological, in situ hybridisation and PCR analysis. No clinical signs or gross and microscopic lesions compatible with PCV2 infections such as those seen in pigs were observed. No presence of PCV2 nucleic acid was detected in rabbits and mice by in situ hybridisation. Only one mouse inoculated with PCV1 seroconverted on day 20 PI. PCV1 and PCV2 genome was detected in serum by PCR in mice inoculated with each porcine circovirus, while rabbits were negative for both viral types. These studies indicated that porcine circoviruses did not cause any disease or microscopic lesions in inoculated rabbits and mice during the experimental period. However, intraperitoneally inoculated mice might have harboured PCV2 in circulation without evidence of viral replication. chacun divisés en deux groupes comprenant des animaux inoculés avec PCV1 et PCV2, et un troisième groupe inoculé avec un milieu de culture non-infecté. Les lapins ont été inoculés par voie intranasale et les souris par voie intrapéritonéale. Les signes cliniques et le poids des animaux ont été enregistrés au début de l'expérience et au moment de l'autopsie. Aux jours 0, 3, 7, 10, 14 et 20 après inoculation, le sang des animaux a été prélevé, puis les animaux ont été euthanasiés et ont subi une autopsie ; des échantillons ont été prélevés pour des analyses histopathologique, sérologique, d'hybridation in situ et de PCR. Aucun signe clinique ni lésion macro-ou microscopique correspondant à ceux observés chez les porcs infectés par PCV2 n'ont été détectés. Aucune présence d'acide nucléique de PCV2 n'a été détectée chez les lapins et les souris par hybridation in situ. Seule une souris inoculée par PCV1 est devenue séropositive au jour 20 post-inoculation. Les génomes de PCV1 et PCV2 ont été détectés par PCR dans le sérum de souris inoculées par chacun des circovirus, alors que les lapins sont restés négatifs pour chacun des types. Ces études indiquent que les circovirus porcins n'ont provoqué aucune maladie ou lésion microscopique chez les lapins et les souris inoculés durant toute la durée de l'expérimentation. Cependant, les souris inoculées expérimentalement pourraient avoir hébergé du virus PCV2 dans la circulation sanguine sans signe de réplication virale.lapin / souris / circovirus porcin / réaction en chaîne par polym...

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“…These other factors seem to play an important role in the development of PMWS in pigs [3,12] and this effect cannot be discounted for non-porcine species.…”

Section: Discussionmentioning

confidence: 98%

Experimental inoculation of porcine circoviruses type 1 (PCV1) and type 2 (PCV2) in rabbits and mice

Quintana

Balasch²,

Segalés

et al. 2002

Vet. Res.

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“…In addition, no significant differences were observed in PCV2 viremia quantification, thus excluding any potentiation effect on viral replication by the adjuvant in this particular trial. It is known that PMWS affected pigs have a higher viral load than subclinically PCV2 infected pigs [12,13,15,16,24]. Therefore, it has been proposed that the use of products that stimulate the immune system, such as vaccines or nonspecific immunostimulators, may potentiate PCV2 replication leading to PMWS [4,12,14].…”

Section: Discussionmentioning

confidence: 99%

“…The hypothesis of the immune system's stimulation by vaccines and/or vaccine adjuvants, as the key event in PMWS development is gaining acceptance, supported by some field and laboratory trials [5,12,14]. The use of Mycoplasma hyopneumoniae vaccines in nursery pigs together with PCV2 inoculation seems to enhance the severity of clinic and pathologic expression of the wasting disease [4,14].…”

Section: Introductionmentioning

confidence: 99%

“…The use of Mycoplasma hyopneumoniae vaccines in nursery pigs together with PCV2 inoculation seems to enhance the severity of clinic and pathologic expression of the wasting disease [4,14]. Moreover, severe PMWS expression is highly prevalent when using PCV2 infected 3-day-old gnotobiotic piglets immune stimulated with keyhole limpet haemocyanin antigen emulsified in incomplete Freund adjuvant (KLH/ICFA) with or without intraperitoneal glycan [12]. However, in the same experimental trial the use of the same immunostimulant injected IM in the neck only induced a subclinical infection [12].…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, severe PMWS expression is highly prevalent when using PCV2 infected 3-day-old gnotobiotic piglets immune stimulated with keyhole limpet haemocyanin antigen emulsified in incomplete Freund adjuvant (KLH/ICFA) with or without intraperitoneal glycan [12]. However, in the same experimental trial the use of the same immunostimulant injected IM in the neck only induced a subclinical infection [12]. Moreover, controversial results have also been observed when KLH/ICFA is administered to 3-week-old SPF pigs [15].…”

Section: Introductionmentioning

confidence: 99%

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Lack of an effect of a commercial vaccine adjuvant on the development of postweaning multisystemic wasting syndrome (PMWS) in porcine circovirus type�2 (PCV2) experimentally infected conventional pigs

Resendes

Segalés

Balasch³

et al. 2004

Vet. Res.

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-The objective of this study was to evaluate the effect of a commercial vaccine adjuvant on the clinical and pathological outcome of PCV2 experimentally infected 8 to 9-week-old conventional pigs. Forty-four pigs were divided into four groups: non-infected control pigs, pigs that received a vaccine adjuvant, pigs inoculated with PCV2, and pigs inoculated with PCV2 together with the vaccine adjuvant. Infection was monitored until 69 days post-inoculation (PI). Some PCV2 inoculated pigs had hyperthermia, but no other clinical signs were recorded. No characteristic PMWS gross or microscopic lesions were observed in any of the pigs. PCV2 DNA was detected in lymphoid tissues by in situ hybridisation in 6 PCV2 inoculated pigs on day 69 PI. All PCV2 inoculated pigs seroconverted between days 21 and 49 PI, shortly after viremia detection. Moreover, viremia was detected between days 7 and 69 PI using PCR. A peak of the virus load was detected by real-time quantitative PCR between days 14 and 21 PI. There were no significant differences in the proportion of PCV2 positive serum and in the viral load between PCV2 and PCV2 + adjuvant inoculated pigs. Although PMWS was not reproduced in neither PCV2 nor PCV2 + adjuvant inoculated pigs, viremia detection and seroconversion indicated that all PCV2 inoculated pigs developed a chronic long-term asymptomatic infection. An increase of PCV2 replication was not observed in pigs inoculated with the adjuvant. These results indicate that the principle of immunostimulation may not be applicable under the experimental conditions used, suggesting that not all adjuvants used in commercial vaccines are capable of triggering mechanisms for PMWS development.

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Postweaning Multisystemic Wasting Syndrome: Experimental Studies with Porcine Circovirus Type 2

Kennedy¹,

Meehan²,

McNeilly³

et al. 2002

Trends in Emerging Viral Infections of Swine

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Activation of the Immune System is the Pivotal Event in the Production of Wasting Disease in Pigs Infected with Porcine Circovirus-2 (PCV-2)

Cited by 250 publications

References 19 publications

Experimental inoculation of porcine circoviruses type 1 (PCV1) and type 2 (PCV2) in rabbits and mice

Experimental inoculation of porcine circoviruses type 1 (PCV1) and type 2 (PCV2) in rabbits and mice

Lack of an effect of a commercial vaccine adjuvant on the development of postweaning multisystemic wasting syndrome (PMWS) in porcine circovirus type�2 (PCV2) experimentally infected conventional pigs

Postweaning Multisystemic Wasting Syndrome: Experimental Studies with Porcine Circovirus Type 2

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