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About PDNS
Porcine Dermatitis and Nephropathy Syndrome - By Jake Waddilive MA, VetMB, MRCVS - March 2001

PMWS & Porcine Circovirus
Dr Geoff Gard, CAHNet Update: Information on the disease plus results of a survey of veterinarians - Spring 1999 (Canada).

PMWS: A New Condition Affecting Pigs
CAHNet - A useful, if rather old article on the disease. Provides a good background to the disease - November 1997

Porcine Circovirus type 2
Dr. Igor Morozov, Iowa State University, Veterinary Medi- cal Research Institute
Emerging Disease Notice
PMWS: Centre for Emerging Issues (CEI)

Emerging Disease Notice
PDNS: Centre for Emerging Issues (CEI), March 2001

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Published Information & Scientific Data
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Published: Veterinary Research Communications, Volume 30, Number 2, February 2006 (Abstract)
Serological Investigation and Genomic Characterization of PCV2 Isolates from Different Geographic Regions of Zhejiang Province in China
Zhou JY, Chen QX, Ye JX, Shen HG, Chen TF, Shang SB.
Sera collected from 46 swine farms in Zhejiang province were evaluated for the presence of antibodies to PCV2 using an indirect-fluorescent antibody procedure. In addition PCV2 isolated from superficial inguinal lymph node samples collected from 40-to 90-day-old pigs with clinical signs of post-weaning multisystemic wasting syndrome (PMWS) using the PK-15 cell line were sequenced and compared. Overall seroprevalence of PCV2 antibody averaged 58.34% for all samples. Breakdown of serology by groups was as follows: 59.38% for sows, 57.41% for post-weaning piglets, 44.83% for Landrace sows and 64.28% for Landrace piglets. The seroprevalence of Landrace sows was higher than that of Yorkshire and Duroc sows, but non-significant (p > 0.05). Serological analysis also showed that seroprevalence of PCV2 antibody was a negative correlation to that of PRRSV antibody. The complete genomes of five PCV2 isolates identified in the herds with PMWS consisted of 1767nt, containing the 11 potential ORFs. Genome of the virus isolates shared 93.8% to 99.8% identity with PCV2 reference strains from GenBank, 76.6% to 77.9% identity with PCV1. Phylogenetic analysis indicated that there were two subgenotypes within PCV2: subgenotype I (1767 nt) and subgenotype II (1768 nt).

Published: Virology - January 2006 (Abstract)
Inhibition of porcine circovirus type 2 replication in mice by RNA interference.
Liu J, Chen I, Chua H, Du Q, Kwang J.
Porcine circovirus type 2 (PCV2) is the primary causative agent of an emerging swine disease, postweaning multisystemic wasting syndrome (PMWS) for which no antiviral treatment is available. To exploit the possibility of using RNA interference (RNAi) as a therapeutic approach against the disease, plasmid-borne short hairpin RNAs (shRNAs) were generated to target the PCV2 genome. Transfection of these shRNAs into cultured PK15 cells caused a significant reduction in viral RNA production that was accompanied by inhibiting viral DNA replication and protein synthesis in infected cells. The effect was further tested in vivo in a mouse model that has been developed for PCV2 infection. Mice injected with shRNA before PCV2 infection showed substantially decreased microscopic lesions in inguinal lymph nodes compared to controls. In situ hybridization and immunohistochemical analyses showed that shRNA caused a significant inhibition in the level of viral DNA and protein synthesis detected in the lymph nodes of the treated mice relative to the controls. Taken together, these results indicate that shRNAs are capable of inhibiting PCV2 infection in vitro as well as in vivo and thus may constitute an effective therapeutic strategy for PCV2 infection

Published: Vet Journal 171(1):166-8. - January 2006 (Abstract)
Identification of porcine circovirus type 2 in retrospective cases of pigs naturally infected with porcine epidemic diarrhoea virus.
Jung K, Ha Y, Ha SK, Kim J, Choi C, Park HK, Kim SH, Chae C.
The identification of porcine circovirus type 2 (PCV2) was studied in fresh intestinal tissues by polymerase chain reaction (PCR) and in formalin-fixed, paraffin-wax-embedded intestinal tissues by in situ hybridisation. The tissues came from pigs naturally infected with porcine epidemic diarrhoea virus (PEDV). A total of 35 (32.7%) of 107 small intestinal samples from pigs naturally infected with PEDV were found to be positive using PCR. Positive signals for PCV2 were detected in 32 (29.9%) of 107 small intestinal samples from pigs naturally infected with PEDV by in situ hybridisation. The distribution of positive cells in the jejunum and ileum was multifocal or patchy. Distinct positive labelling was found throughout the lamina propria in the small intestines. The results of this study indicate that PCV2 is highly prevalent in pigs naturally infected with PEDV.

Published: J Comp Pathol January 2006 (Abstract)
Cardiovascular lesions in pigs naturally or experimentally infected with porcine circovirus type 2.
Opriessnig T, Janke BH, Halbur PG.
Abundant intracytoplasmic porcine circovirus type 2 (PCV2) was associated with myocardiocyte swelling or necrosis, or myocardial fibrosis (or both) in three naturally infected pigs aged 4-7 weeks from three different farms. One 6 week old pig from a fourth farm had severe diffuse segmental to circumferential lymphohistiocytic and plasmacytic periarteritis and endarteritis in several organs, PCV2 antigen was demonstrated in endothelial cells, and inflammatory cells in the arterial walls. In three pigs experimentally infected with PCV2, viral antigen was also associated with obliterated blood vessels in areas of granulomatous and necrotizing lymphadenitis. Together these findings suggest that the cardiovascular system in general and endothelial cells in particular play an important role in the pathogenesis of PCV2-associated diseases.

Published: Res Vet Sci - December 2005 (Abstract)
Pathological and aetiological studies of multifocal interstitial nephritis in wasted pigs at slaughter.
Martinez J, Segales J, Aduriz G, Atxaerandio R, Jaro P, Ortega J, Peris B, Corpa JM.
Multifocal interstitial nephritis in pigs has been associated with several infectious agents. The objective of the present study was to investigate several different potential infectious agents associated with "white-spotted" kidneys in pigs suffering from wasting at slaughter (aged 6-8 months). Twenty-nine case kidneys (with a "white-spotted" gross appearance) classified into 3 macroscopic lesional grades, and 15 control kidneys (lacking gross lesions), were obtained from a pig abattoir. Laboratory analyses to detect potential associations with the aforementioned pathological condition with Leptospira spp., porcine circovirus type 2 (PCV2), porcine parvovirus (PPV), porcine reproductive and respiratory syndrome virus (PRRSV), and bacteria, were carried out. Microscopically, interstitial nephritis with a lymphofollicular inflammatory pattern (follicular nephritis) was observed in both case and control kidneys, with a higher frequency seen in the former ones. No leptospires were identified, although antibodies to the Pomona and Bratislava serovars were detected. Some pyogenic bacteria were also isolated from both case and control kidneys. PCV2 nucleic acid was only detected in 1 case kidney. PRRSV antigen was not found in any tested sample. Some pigs were tested positive for PPV by serology. Apparently, none of the studied agents were specifically associated as being the potential cause of the renal lesions in the studied wasted pigs. The fact that these chronic lesions may have been the consequence of a previous infection with one of these studied microorganisms, or more, and eventually with other non-tested infectious agents during the growing-finishing period, cannot be ruled out.

Published: Arch Virol. Nov 2005 (Abstract)
Genetic characterization of type 2 porcine circoviruses detected in Hungarian wild boars.
Csagola A, Kecskemeti S, Kardos G, Kiss I, Tuboly T.
Porcine circoviruses (PCV) are present in pigs worldwide; they are grouped into two types: PCV1 comprising non-pathogenic viruses and PCV2 responsible for several clinical manifestations. Both types are frequently detected in domestic pigs, the prevalence and role of PCV in wild boars however, is not well studied. During the years 2002-2003 over 2000 organ samples of Hungarian wild boars were collected, grouped and samples from 307 different animals were tested by polymerase chain reaction for the presence of PCV. 35.5% of the wild boars were positive for one or both PCV types and PCV2 was detected in 20.5% of the animals. The PCV2 viruses were divided into 7 groups (WB-H1-7) based on sequencing data and genomes representing these groups were sequenced completely. The wild boar PCV2 groups were distributed evenly in the geographical region, regardless of the time and place of collection. The phylogenetic analysis of the PCV2 sequences of wild boar and domestic pig origin showed the possibility of an epidemiological link between wild boar and domestic pig infections. Interestingly, the complete nucleotide sequence of the viruses and the predicted amino acid sequence of the replication associated protein (ORF1) grouped the viruses similarly, whereas the capsid protein (ORF2) comparisons revealed different relations among the groups, suggesting the possibility of genomic recombination in PCV2.

Published: Xenotransplantation Volume 12 Issue 6 Page 465 - November 2005 (Abstract)
Ultrastructural alterations in human blood leukocytes induced by porcine circovirus type 1 infection
Gabriel Arteaga-Troncoso, Fernando Guerra-Infante, Luz Maria Rosales-Montaño, Francisco Javier Díaz-García and Saúl Flores-Medina
Background: Swine infectious pathogens, especially viruses, represent a potential public health risk associated with the use of pig tissues for xenotransplantation in humans. We hypothesized that porcine circovirus type I (PCV-1) may infect human mononuclear cells, resulting in ultrastructural alterations of the target cells.
Methods: Transmission electron microscopy was used for evaluating ultrastructural alterations of human cells exposed to a PCV-infected PK15 cell line. A polymerase chain reaction (PCR) assay and fluorescence in situ hybridization (FISH) were developed for detecting PCV-1 in human mononuclear cells.
Results: Morphological alterations of the human T cells exposed to PCV PK15 showed ''boomerang-shaped'' intracytoplasmic inclusions. Nucleocapsids appeared free, close to the nucleus, or contained into cytoplasmic vacuoles. Virions were observed near the surface of the human cells. A considerable number of mature virions and immature forms could be observed in the human cells that had a completely intact nuclear membrane with no alteration in the disposition of chromatin. PCV-1 particles were identified budding into typical Golgi saccules and vacuoles. Virions sized up to 23 nm in diameter, and appeared in the nucleus and in the periphery of the cellular core. PCV-1 infection was detected on CD4+, CD8+, CD14+, CD19+, and CD56+ human cells by PCR assay and FISH.
Conclusions: These results suggest that PCV has the capability of infecting human leukocytes in vitro, and should be considered a potential risk of viral transmission during xenotransplantation.

Published: J Interferon Cytokine Res. - 25(11):684-93 Nov 2005 (Abstract)
Enhancement of porcine circovirus 2 replication in porcine cell lines by IFN-gamma before and after treatment and by IFN-alpha after treatment.
Meerts P, Misinzo G, Nauwynck HJ.
Stimulation of the porcine immune system causes increased replication of porcine circovirus 2 (PCV2) in vivo. In the present study, we investigated whether various cytokines (interleukin-1 [IL-1], IL-6, IL-10, tumor necrosis factor-alpha [TNF-alpha], interferon-alpha [IFN-alpha], and IFN-gamma) are able to influence PCV2 infection in vitro. No changes were observed in IL-1, IL-6, TNF-alpha, or IL-10-treated cells. However, it was demonstrated that IFN- alpha and IFN-gamma influenced PCV2 infection in porcine kidney cells (PK-15) and porcine monocytic cells (3D4/31). IFN-gamma added to the culture medium before, during, or after inoculation increased the number of PCV2 antigen- positive cells, respectively, by 418%, 171%, and 691% in PK-15 cells and by 706%, 114%, and 423% in 3D4/31 cells. IFN-alpha pretreatment decreased the number of infected PK-15 cells. When it was added after inoculation, IFN-alpha enhanced PCV2 infection by 529% in PK-15 cells and by 308% in 3D4/31 cells. The effect of both IFNs on PCV2 infection was dose dependent and could be blocked with IFN-alpha or IFN-gamma neutralizing antibodies. Leukocyte-derived porcine IFN-gamma induced a similar effect on PCV2 infection. Treatment of PK- 15 cultures with IFN-gamma caused a 20 times higher production of progeny virus. Confocal microscopy studies showed that the enhancing effect of IFN-gamma on PCV2 infection was achieved by increased internalization of PCV2 virionlike particles (VLPs). Binding of the VLPs to the cell or expression kinetics of PCV2 proteins in infected cells were not altered by IFN-gamma treatment. To our knowledge, this study reports the first enhancement of a viral infection by treatment with type I or type II IFNs.

Published: Vet Immunol Immunopathol. 24 - Nov 2005 (Abstract)
Immunopathological effects of porcine circovirus type 2 (PCV2) on swine alveolar macrophages by in vitro inoculation.
Chang HW, Jeng CR, Lin TL, Liu JJ, Chiou MT, Tsai YC, Chia MY, Jan TR, Pang VF.
Porcine circovirus type 2 (PCV2) is the primary causative agent of postweaning multisystemic wasting syndrome (PMWS), a multifactorial disease, in pigs. Monocyte/macrophage lineage cells, including alveolar macrophages (AMs), are the major target cells for PCV2. Swine AMs are essential for the pulmonary defense system against various pathogens. Concurrent infection of lung with opportunistic pathogens in pigs suffered from PMWS is speculated as a feature of immunosuppression. The present study was conducted to characterize the effects of PCV2 inoculation on swine AMs in the in vitro system. The parameters selected for evaluation included PCV2 antigen- and nucleic acid-containing rate, viability, TUNEL-positive rate, phagocytosis, microbicidal capability, and capacity for production of reactive oxygen species (superoxide anion, O(2)(-), and hydrogen peroxide, H(2)O(2)), cytokines, and chemokines. High intracytoplasmic PCV2 antigen- and nucleic acid-containing rate, absence of intranuclear signals for PCV2 antigen and nucleic acid, and lack of noticeable cell death were seen in PCV2-inoculated AMs. The PCV2-inoculated AMs displayed a transient as well as persistent reduction in the up-take and destruction of Candida albicans, respectively, accompanied by decrease in the production of O(2)(-) and H(2)O(2). In PCV2-inoculated AMs, the levels of tumor necrosis-alpha (TNF-alpha) and interleukin-8 (IL-8) were significantly increased; the mRNA expression levels of alveolar macrophage-derived neutrophil chemotactic factors-II (AMCF-II), granulocyte colony-stimulating factor (G-CSF), monocyte chemotactic protein-1 (MCP-1), and IL-8 were strongly up-regulated. The reduced phagocytosis and microbicidal capability in conjunction with decreased production of reactive oxygen species in PCV2-inoculated AMs suggest that PCV2-containing AMs may favor the survival and spread of PCV2. It is speculated that the functional alterations observed in PCV2-containing AMs may be potentially harmful to the lung tissue and local pulmonary defense system, especially in those PCV2-infected pigs conditioned by various PMWS development-dependent co-factors.

Published: Clin Diagn Lab Immunol. - 12(11):1347-51. - Nov 2005 (Abstract)
Effects of porcine circovirus type 2 (PCV2) maternal antibodies on experimental infection of piglets with PCV2.
McKeown NE, Opriessnig T, Thomas P, Guenette DK, Elvinger F, Fenaux M, Halbur PG, Meng XJ.
To determine the effects of porcine circovirus type 2 (PCV2) maternal antibodies on and response to experimental PCV2 infection, 24 piglets were divided into four groups on the basis of the enzyme-linked immunosorbent assay titers of PCV2 maternal antibodies: group A (n = 6; sample/positive [S/P] ratio, <0.2), group B (n = 5; S/P ratio, >0.2 to <0.5), and groups C (n = 8) and D (n = 5) (S/P ratio, >0.5). Piglets in groups A, B, and C were inoculated with PCV2 at day 0 and challenged with PCV2 at day 42. Group D piglets were not exposed to PCV2 at day 0 but were challenged at day 42. Before challenge, seroconversion to PCV2 antibodies occurred in five of six group A piglets, and the antibody level rose above the cutoff level in one of five group B piglets. Viremia was detected in five of six, four of five, and two of eight pigs in groups A, B, and C, respectively. After challenge, PCV2 DNA was detectable from 7 to 21 days postchallenge in the sera from six of six, four of five, three of eight, and five of five pigs in groups A, B, C, and D, respectively. The results indicated that protection against PCV2 infection conferred by maternal antibodies is titer dependent: higher titers are generally protective, but low titers are not.

Published: Veterinary Microbiology, In Press, Corrected Proof, Available online 9 November 2005 (Abstract)
Quantification of porcine circovirus type 2 (PCV2) DNA in serum and tonsillar, nasal, tracheo-bronchial, urinary and faecal swabs of pigs with and without postweaning multisystemic wasting syndrome (PMWS)
J. Segal?s, M. Calsamiglia, A. Olvera, M. Sibila, L. Badiella and M. Domingo The present study focused on PCV2 quantification by TaqMan PCR in nasal (n = 99), tonsillar (n = 108), tracheo-bronchial (n = 72), urinary (n = 91) and faecal (n = 42) swabs, as well as in serum (n = 57), from a total of 146 pigs received at the Pathological Diagnostic Service at the Veterinary School of Barcelona (Spain). Animals were classified into three categories based on histopathological and in situ hybridisation (ISH) results: PMWS affected pigs (Group A, n = 42), PCV2 subclinically infected pigs (Group B, n = 29), and non-PMWS with PCV2 ISH negative pigs (Group C, n = 75). Overall, tracheo-bronchial swabs had the higher PCV2 load followed by serum, tonsillar, nasal, faecal and, finally, urinary swabs. PCV2 genome was also detected in different proportions in all three categories of pigs; in all tested sites, viral load means were significantly higher (P ≤  0.02) in animals with PMWS (Group A pigs) than in animals without PMWS (Group B and C pigs). Therefore, the more severe the lesions, the higher amounts of viral genome by ISH, and the higher PCV2 load in serum and swab specimens. Except for the tracheo-bronchial swab, no significant differences (p > 0.05) were observed among tested specimens when age-groups (pigs younger than 1.5 months, and equal or older than 1.5 months of age) were compared. In summary, PCV2 is presumably excreted through respiratory (nasal and tracheo-bronchial) and oral (tonsillar) secretions, urine and faeces of both PMWS and non-PMWS affected pigs, with higher viral loads being associated with the presence of PMWS lesions.

Published: Pig Journal Volume: 56 - Nov 2005 - (Abstract)
Post-weaning Multisystemic Wasting Syndrome (PMWS) in Denmark - The situation to date
P. Baekbo
Post-wasting Multisystemic Wasting Syndrome (PMWS) was first diagnosed in Denmark in 2000. In April 2005, Denmark had 541 confirmed cases of PMWS. This corresponds to a prevalence of approximately 10 per cent of all sow herds. However, the estimated real prevalence is 17 per cent. The PMWS-affected herds are widespread, with the highest prevalence in the most pig dense areas. Recorded PMWS cases are based on clinical signs in the herd and on laboratory tests (histopathology). Post-wasting Multisystemic Wasting Syndrome is mainly seen among weaners and gives high mortality and reduced growth rate. The productivity of finishers in affected herds also seems to be reduced. The options for controlling PMWS are based on changes in management aimed at reducing stress on pigs, reducing potential transmission of pathogens between pigs and of ensuring a high level of hygiene. Research on the aetiology and control of PMWS has had high priority during the last five years.

Published: Pig Journal Volume: 56 - Nov 2005 - (Abstract)
Postweaning Multisystemic Wasting Syndrome (PMWS) Research in Denmark
P. Baekbo
In Denmark, much research on PMWS takes place in co-operation between the pig industry and public research institutes. Completed studies indicate that PMWS can be transmitted from pig to pig and that low levels of Vitamin E at weaning increase the risk of dying during the post-weaning period. Total depopulation/repopulation and autogeneous serum are options for controlling PMWS, whereas feed supplement with so-called immune stimulation substances seem to be of no effect. Ongoing studies focus on detecting possible risk factors for the development of PMWS and possible differences in virulence of PCV2 isolates. The studies also search for possible unknown infectious trigger agents for PCV2. Future research to be started in Denmark is mainly concentrated on a big EU project. Focus will be on epidemiology of PMWS, on genetic susceptibility and on control measures for PMWS. Furthermore, a small field study will be performed on the efficacy of Acetylsalicylic acid for reduction of post-weaning mortality in PMWS-affected herds.

Published: Pig Journal Volume: 56 - Nov 2005 - (Abstract)
Postweaning Multisystemic Wasting Syndrome (PMWS) in purebred wild boar (Sus Scrofa) on a farm in East Anglia
N.G.A. Woodger
Post-weaning multisystemic wasting syndrome (PMWS) was diagnosed in farmed Wild Boar in East Anglia. This involved an overstocked unit, resulting from movement restrictions following the 2001 Foot-and-Mouth disease epidemic.
A severe wasting disease with scouring, coughing and anorexia was first noticed in growing pigs from 3-4 months of age, in April 2003. There was a marked increase in mortality, which approached 50 per cent of all growing pigs. This paper describes the background, laboratory findings and conclusions leading to the diagnosis of PMWS and other diseases after post-mortems on seven affected pigs. Possible sources and the impact of management changes are discussed.
Several reports of PMWS in Eurasian Wild Boar in Canada, Spain and Germany are recorded; but this would appear to be the first report of PMWS in farmed purebred Wild Boar in the UK.

Published: Pig Journal Volume: 56 - Nov 2005 - (Abstract)
Post-weaning Multisystemic Wasting Syndrome (PMWS) in Farms: Defining disease and the role of Porcine Circovirus 2 (PCV2)
M. Turner, C. Schnier, K. Woodbine, L. Green, G. Medley and J. Slevin
The cause of PMWS is as yet undetermined. There has been great controversy over the role of PCV2 in the disease. Current case definitions for the disease vary, but all include the presence of PCV2 antigen or nucleic acid. In a cross-sectional study of 116 farms, there was little difference in the PCV2 serological profiles of PMWS positive, negative and recovered farms. However, PCV2 antigen levels were more raised in sick pigs on all farms. There were also high levels on farms where the farmers had not reported PMWS and some positive farms where no antigen was detected. Antigen levels were correlated with current mortality with PMWS on the farms. Porcine circovirus 2 was not included in the proposed case definition due to the uncertainty of its role in the disease.
There were 28 significant differences between the post-mortem examination (PME) of sick and healthy pigs, ignoring farm of origin. These differences were mainly enteric and respiratory. There were three significant differences between the histology results from sick and healthy pigs. These differences were significant in the ileoceacocolic lymph node. A case definition has been proposed using these significantly different signs.

Published: Pig Journal Volume: 56 - Nov 2005 - (Abstract)
The use of PRACETAM (Paracetamol) premix in Post-weaning Multisystemic Wasting Syndrome (PMWS) and Post-weaning diets
L. Glattleider and N. Capdevielle
Controlled clinical trials were performed to evaluate the effect of PRACETAM in either PMWS or in a post-weaning diet.
The efficacy of PRACETAM was demonstrated by a controlled clinical trial under blind conditions in a pig herd chronically infected with PMWS. The therapeutic dose in the treated group was 30 milligrams of Paracetamol per kilograms body weight (1000 milligrams per kilogram of feed) for ten consecutive days and no concomitant antibiotic treatment was used. During the first period of the trial (between day 0 and day fourteen), only a small number of pigs died or lost weight. The difference between the treated and control group was not significant. During the second period of the trial, a statistically significant difference in the number of dead or wasting pigs was observed between the treated and control group and treatment with PRACETAM was concluded to have helped in reducing the mortality rate and the number of wasting piglets.
A controlled trial was carried out to evaluate the effect of PRACETAM on growth rate during the post-weaning period. Three hundred and fifty-one piglets were involved in this study, from the day of weaning (day zero) to the end of the post- weaning period (day 35), randomly divided into a control and a treated group and reared under different conditions. Under favourable conditions (5 piglets per box and completely slatted floor), a significant effect of PRACETAM was observed on growth performance with daily weight gain 55g higher than in the control group). Under unfavourable conditions (10 piglets per box, partially slatted floor and stimulation of the immune system by vaccination against Mycoplasma), an even greater effect of PRACETAM was seen throughout the growth period, despite the immune stimulation.

Published: BMC Vet Res. - 31;1:7. - October 2005 (Abstract)
Porcine circovirus type 2 (PCV2) causes apoptosis in experimentally inoculated BALB/c mice.
Kiupel M, Stevenson GW, Galbreath EJ, North A, HogenEsch H, Mittal SK.
BACKGROUND: We have previously described microscopic and electron microscopic alterations in lymphoid organs of PCV2 inoculated mice as apoptosis. In this study we wanted to investigate the molecular pathogenetic mechanism of PCV2-induced apoptosis. Eight-week old BALB/c mice were either sham inoculated (control mice) or inoculated intraperitoneally (ip) and intranasally (in) with a single (sPCV mice) or multiple (mPCV mice) doses of PCV2. Four control mice and 4 sPCV mice were sacrificed 7, 14, 28 and 42 days post inoculation (PI). All 4 mPCV mice were sacrificed 42 days PI. Following necropsy, immunohistochemistry for caspase 3 and in-situ TUNEL assay were performed on sections of spleen, lymph nodes, thymus and ileum from control, sPCV and mPCV mice. In addition, total RNA was extracted from spleens of control, sPCV and mPCV mice for simultaneous detection and semiquantitation of bcl-2 homologues and various caspase mRNAs using a multiprobe RNase protection assay system. RESULTS: PCV2 replicated and was associated with apoptosis in spleens, lymph nodes and Peyer's patches of infected BALB/c mice. Upregulation of caspase 1, 2, 3, 6, 7, 8, 11 and 12 and upregulation for the transcripts of apoptosis inhibitors bcl-2, bcl-w and bcl-X and apoptosis promoters' bax, bak and bad was detected in spleens of sPCV and mPCV mice, but not control mice. Apoptosis was further confirmed by light and electron microscopic morphology as well as by positive TUNEL assay and detection of activated caspase 3. PCV2 nucleic acid was detected by in-situ hybridization in the nuclei and cytoplasm of such apoptotic cells. CONCLUSION: The data presented here support the hypothesis that PCV2 induces apoptosis mediated through the activation of caspases 8 and 3 in the spleens of infected mice.

Published: Dtsch Tierarztl Wochenschr. - 112(9):348-51. - Sep 2005 (Abstract)
Prevalence and association of porcine circovirus type 2 (PCV2), porcine parvovirus (PPV) and porcine reproductive and respiratory syndrome virus (PRRSV) in aborted fetuses, mummified fetuses, stillborn and nonviable neonatal piglets
Ritzmann M, Wilhelm S, Zimmermann P, Etschmann B, Bogner KH, Selbitz HJ, Heinritzi K, Truyen U.
Porcine circovirus type 2 (PCV2) seems to cause reproductive failure in sows not only in experimental studies. A retrospective study was made with a total of 252 aborted fetuses, mummified fetuses, stillborn and nonviable neonatal piglets to determine the presence of PCV2, porcine parvovirus (PPV) and porcine respiratory and reproductive syndrome virus (PRRSV) by PCR. PCV2 was found in all stages of gestation in 27.1 percent of samples examined. A statistically significant association could be shown between the detection of PCV2 and PRRSV. However, no significant association was seen between the detection of PCV2 and PPV and between PPV and PRRSV.

Published: Vet Microbiol - 30;110(1-2):141-6.- Sep 2005 (Abstract)
Genotyping of porcine circovirus type 2 from a variety of clinical conditions in China.
Wen L, Guo X, Yang H.
Genotypes of porcine circovirus type 2 (PCV2) in clinical tissue specimens collected from pigs of different region in China between 2001 and 2003 were analyzed by PCR and restriction fragment length polymorphism (RFLP) analysis of PCV2 genomic DNA encompassing the complete ORF2. The results showed that nine different genotypes (A-I) were identified and designated CHN-2A, CHN-2B, CHN-2C, CHN-2D, CHN-2E, CHN-2F, CHN-2G, CHN-2H and CHN-2I, respectively. Amongst the genotypes, 0.6% were CHN-2A (1/173), CHN-2B (1/173) and CHN-2C (1/173) RFLP profile; 2.3% were CHN-2F (4/173) and CHN-2G (4/173); 5.8% were CHN-2D (10/173); 8.6% were CHN-2E (15/173); 18.5% were CHN-2I (32/173) and 60.7% were CHN-2H (105/173). Therefore, our results suggest that CHN-2H is the dominant genotype of PCV2 prevailing in China. Sequence analysis revealed that ORF2 genes of different genotypic PCV2 exhibited the variation extent of 90.5-99.5% and 88-100% in nucleotide and amino acid respectively. The deduced amino acid sequences alignment of the capsid protein encoded by ORF2 of PCV2 presented that three major regions with greater heterogeneity existed at residues 57-90, 121-136 and 180-191 among nine genotypic PCV2. It was concluded that there exist variation in ORF2 genes of different genotypic PCV2 prevailing in China.

Published: Vet Q. - 27(3):105-16 - September 2005 (Abstract)
Postweaning multisystemic wasting syndrome (PMWS) in pigs with particular emphasis on the causative agent, the mode of transmission, the diagnostic tools and the control measures. A review.
Ghebremariam MK, Gruys E.
Department of Pathobiology, Faculty of Veterinary Medicine, University of Utrecht, The Netherlands.
Postweaning multisystemic wasting syndrome (PMWS) is a worldwide emerging disease of weaned piglets. The objective of this review is to summarize the current knowledge regarding PMWS, its causative agent, mode of transmission, diagnostic techniques to detect PCV-2, the possible control measures, and the association of PMWS and PCV-2 with porcine dermatitis and nephropathy syndrome (PDNS). The causative agent of PMWS is porcine circovirus type 2 (PCV-2), however, not all pigs infected with PCV-2 develop the syndrome.
PCV-2 is consistently associated with PMWS and PMWS is considered not to occur without it. Both the syndrome and the virus are not regarded as new. Co-factors that could activate PCV-2 to cause PMWS are considered. This enigmatic nature of both the syndrome and the virus is triggering a concern towards uncertainties of the viral transmission, its introduction in to the herd, effective tools of diagnosis, and control strategies.

Published: Vet Res - 36(5-6):685-97. - September 2005 (Abstract)
Reproduction of PMWS in immunostimulated SPF piglets transfected with infectious cloned genomic DNA of type 2 porcine circovirus
Grasland B, Loizel C, Blanchard P, Oger A, Nignol AC, Bigarre L, Morvan H, Cariolet R, Jestin A.
French agency for food safety (AFSSA), Unit of Viral Genetics and Biosafety, BP 53, 22440 Ploufragan, France.
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.

Published: Vet Microbiol - 30;110(1-2):17-26 - September 2005 (Abstract)
Spatial and temporal patterns of pig herds diagnosed with Postweaning Multisystemic Wasting Syndrome (PMWS) during the first two years of its occurrence in Denmark.
Vigre H, Baekbo P, Jorsal SE, Bille-Hansen V, Hassing AG, Enoe C, Botner A.
The Danish Institute for Food and Veterinary Research, Department of Epidemiology and Risk Assessment, Morkhoj Bygade 19, DK-2860 Soborg, Denmark.
The clinical syndrome Postweaning Multisystemic Wasting Syndrome (PMWS) in pigs has emerged globally during the last decade. In October 2001, the first pig herd diagnosed with PMWS was reported in Denmark, and since then the number of herds diagnosed with PMWS has increased markedly. The etiology of PMWS is not well understood, but increased knowledge of the causal factors is prerequisite for applying preventive interventions. In this study we described the temporal (time of diagnosis), spatial (location of herds) and spatio-temporal pattern of Danish pig herds diagnosed with PMWS during the first two years after the first herd was diagnosed, and we tested for spatial and spatio-temporal clustering using scan statistics. The study population consisted of pig herds that during the study period (October 2001-September 2003) performed diagnostic submissions to the two major veterinary diagnostic laboratories in Denmark (6724 herds). Of these, 277 herds were diagnosed with PMWS. Two statistically significant spatial clusters of herds diagnosed with PMWS were identified. These clusters included 11% and 8% of the study herds, respectively. Within these two clusters the relative risk for a herd to be diagnosed with PMWS was twice as high as expected. One statistically significant spatio-temporal cluster was identified between February and May 2002. We discuss different hypotheses that could explain why pig herds diagnosed with PMWS were clustered both spatially and spatio-temporally, and conclude that the results support the hypothesis that PMWS is caused by introduction of a new, unidentified, pathogen into the Danish pig production.


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Information on other circovirus diseases

Published: May 2001
Can Replication of Beak and Feather Disease Virus be Controlled? Two Proposals
Frank D. Niagro, Clinical Investigation Division, Dwight D. Eisenhower Army Medical Center, Fort Gordon, GA - The unique properties of the beak and feather disease virus presents a potential for therapeutic intervention in affected animals. The probable rolling-circle mode of viral DNA replication and features of the viral replication protein suggest that either conventional drug intervention or gene therapy-based approaches might be developed.

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