The Effects of Immuno-modulation on the Clinical and Pathological Expression of Postweaning Multisystemic Wasting Syndrome

Kyriakis, S. C.; Saoulidis, K.; Lekkas, S.; Miliotis, Ch. C.; Παπουτσησ), P. A. Papoutsis (Π.Α.; Kennedy, S.

doi:10.1053/jcpa.2001.0520

Cited by 85 publications

(74 citation statements)

References 13 publications

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“…Levels of viral DNA in tissues parallel viral infectivity data (Meehan BM, Gilpin DF, Krakowka S, et al In: Proc ssDNA Viruses of Plants, Birds, Pigs and Primates. St. Malo, FR, Sept [24][25][26][27]2001). …”

Section: Introductionmentioning

confidence: 99%

Features of Porcine Circovirus-2 Disease: Correlations between Lesions, Amount and Distribution of Virus, and Clinical Outcome

Krakowka

Ellis

McNeilly³

et al. 2005

J VET Diagn Invest

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Abstract. Tissue sets from 36 snatch-farrowed colostrum-deprived (SF/CD) and 71 Caesarian-derived gnotobiotic swine infected with porcine circovirus type 2 (PCV-2) as neonates were examined and scored for the types and tissue distribution of histologic lesions associated with this viral infection. The occurrence and severity of these lesions were correlated with qualitative and quantitative determinations of viral burden in tissues by immunohistochemistry (IHC) and tissue titrations for infectious virus, respectively. These measures were, in turn, related to 1 of 3 categories of clinical disease expressed in PCV-2-infected swine as subclinical infection, preclinical postweaning multisystemic wasting syndrome (PMWS), and clinically evident PMWS, respectively. Statistically significant (P Ͻ 0.05 to 0.001) associations between both measures of viral burden, the severity of histologic lesions and the stage of disease were obtained. Discrimination between and among categories of disease was best accomplished by a combination of IHC and histopathology. The results of this study confirm that viral burden in PCV-2-infected tissues, specifically lymphoid tissues and liver, directly correlate with severity of clinical disease expression in PCV-2 infected swine.

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Section: Introductionmentioning

confidence: 99%

Features of Porcine Circovirus-2 Disease: Correlations between Lesions, Amount and Distribution of Virus, and Clinical Outcome

Krakowka

Ellis

McNeilly³

et al. 2005

J VET Diagn Invest

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“…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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“…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]. In the present study, the use of a commercial adjuvant in PCV2 infected pigs did not result in PMWS, suggesting that not all adjuvants used in commercial vaccines may be capable of triggering the mechanisms that potentiate PCV2 replication and generate disease.…”

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].…”

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 Effects of Immuno-modulation on the Clinical and Pathological Expression of Postweaning Multisystemic Wasting Syndrome

Cited by 85 publications

References 13 publications

Features of Porcine Circovirus-2 Disease: Correlations between Lesions, Amount and Distribution of Virus, and Clinical Outcome

Features of Porcine Circovirus-2 Disease: Correlations between Lesions, Amount and Distribution of Virus, and Clinical Outcome

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

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