Experimental Reproduction of Severe Wasting Disease by Co-infection of Pigs with Porcine Circovirus and Porcine Parvovirus

Allan, Gordon; Kennedy, S.; McNeilly, F.; Foster, J.C.; Ellis, John; Krakowka, S; Meehan, Brian; Adair, B. M.

doi:10.1053/jcpa.1998.0295

Cited by 370 publications

(379 citation statements)

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“…However, some recent studies have reported reproduction of the complete disease in specific-pathogen-free (SPF) piglets [1], and in cesarean-derived colostrum-deprived piglets [8,19] but with a non-purified preparation of PCV2. Moreover, the lesions were more acute when the PCV2 inoculates were combined with either porcine parvovirus (PPV) [3,21,22] or porcine reproductive and respiratory syndrome virus (PRRSV) [19]. The immunostimulation also influences the PMWS development [4,23,24,30].…”

Section: Introductionmentioning

confidence: 99%

Reproduction of PMWS in immunostimulated SPF piglets transfected with infectious cloned genomic DNA of type 2 porcine circovirus

et al. 2005

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-Postweaning multisystemic wasting syndrome (PMWS) is a recently emerged disease affecting pigs. Type 2 porcine circovirus (PCV2) has been associated with this syndrome although other factors are required in association with this virus for PMWS expression. The aim of this study was to investigate whether general immunostimulation (injections of keyhole limpet hemocyanin emulsified in incomplete Freund adjuvant and of thioglycollate medium) could strengthen the severity of PMWS in six-week-old specific-pathogen-free (SPF) piglets transfected with pure tandem-cloned PCV2 DNA by the intramuscular route. Non-immunostimulated piglets transfected with the viral clone did not present clinical signs but only mild pathological microlesions characteristic of PMWS. These piglets seroconverted and high viral genome loads and infectious titers were detected in the lymphoid organs at the end of the trial. Mild-to-moderate forms of PMWS were generally observed in the immunostimulated transfected piglets, as well as one severe form for a piglet (8003) which died. These piglets with mild-to-moderate forms had higher DNA loads than the transfected-only animals. Thus, viral replication was enhanced by immunostimulation. This is the first time that clinical PMWS has been reported in an SPF immunostimulated piglet infected with a pure inoculum consisting of tandem-cloned PCV2 DNA. This result confirms that PCV2 is the agent of PMWS and that immunostimulation could enhance PMWS in SPF piglets transfected with a PCV2 DNA clone. porcine circovirus type 2 / immunostimulation / tandem-cloned DNA / PMWS

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Section: Introductionmentioning

confidence: 99%

Reproduction of PMWS in immunostimulated SPF piglets transfected with infectious cloned genomic DNA of type 2 porcine circovirus

et al. 2005

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“…The genome consists of a singlestranded molecule of circular DNA [18,25]. PCV2 is recognised as the cause of a clinical condition of swine named postweaning multisystemic wasting syndrome (PMWS) [2,7,9]. This disease mainly affects 5 to 12 week-old pigs, and is clinically characterised by growth retardation, skin pallor, dyspnea, and enlargement of the inguinal lymph nodes.…”

Section: Introductionmentioning

confidence: 99%

“…Koch postulates have been fulfilled for PCV2 as the primary cause of PMWS [2,7,10]. However, the severe clinical expression observed in field cases has been difficult to reproduce experimentally [1], suggesting that the disease is probably of multifactorial aetiology and/or that not all hosts are susceptible to the development of the disease.…”

Section: Introductionmentioning

confidence: 99%

“…However, the severe clinical expression observed in field cases has been difficult to reproduce experimentally [1], suggesting that the disease is probably of multifactorial aetiology and/or that not all hosts are susceptible to the development of the disease. Experimentally, a synergistic relationship is observed when PCV2 is coinoculated with porcine parvovirus (PPV) or porcine reproductive and respiratory syndrome virus (PRRSV), resulting in a more severe expression of PMWS [2,3,9,11,24]. These studies did not elucidate the synergistic mechanism between those viruses and PCV2, but it is suggested that the activation of the cells from the monocyte/macrophage lineage by PPV and PRRSV could support an increase of PCV2 replication [2,3].…”

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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“…The infectivity capacity of PCV-2 detected in feces was not tested; however, the quantitative values of PCV-2 in feces were associated with the values in tissues of the gastrointestinal tract in PCV-2 affected pigs. Virus titration in different tissues was previously correlated with clinical situation (Allan et al, 1999), making possible the suggestion that the virus present in the feces of those PCV-2 affected pigs had infectivity capacity. Similar results were observed with rectal swabs by Segalés et al (2005).…”

mentioning

confidence: 99%

Porcine circovirus-2 load in the gastrointestinal tract, mesenteric lymph node, tonsil, and feces of wasted pigs with and without diarrhea

Zlotowski

Corrêa

Castro

et al. 2010

Arq. Bras. Med. Vet. Zootec.

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Experimental Reproduction of Severe Wasting Disease by Co-infection of Pigs with Porcine Circovirus and Porcine Parvovirus

Cited by 370 publications

References 0 publications

Reproduction of PMWS in immunostimulated SPF piglets transfected with infectious cloned genomic DNA of type 2 porcine circovirus

Reproduction of PMWS in immunostimulated SPF piglets transfected with infectious cloned genomic DNA of type 2 porcine circovirus

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

Porcine circovirus-2 load in the gastrointestinal tract, mesenteric lymph node, tonsil, and feces of wasted pigs with and without diarrhea

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