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VIROLOGIE
Aujeszky’s disease
• The use of different vaccination
schedules for sows to protect piglets against Aujeszky’s
disease.
Swine influenza
• Experimental dual infection of pigs with
an H1N1 swine influenza virus (A/Sw/Hok/2/81) and Mycoplasma
hyopneumoniae.
PRRS
• PRRS still a mystery.
• Evaluation of the role of mallard ducks
as vectors of porcine reproductive and respiratory syndrome
virus.
• Porcine reproductive and respiratory
syndrome (PPRS) virus – an update.
PORCINE RESPIRATORY DISEASE COMPLEX
(PRDC)
• Association of porcine
circovirus 2 with porcine respiratory disease complex.
PMWS-CIRCOVIRUS-PDNS
• Post-weaning Multisystemic
Wasting Syndrome in Asia.
• La MAP: où en est-on ? (PMWS : where
are we up to ?)
• Cas concrets de maîtrise
de la maladie en Espagne (Field cases of control of PMWS in
Spain).
• Cas concrets de maîtrise de la maladie
en Italie : deux cas cliniques différents (Field cases
of control of PMWS in Italy: two different clinical cases).
• Cas concrets de maîtrise
de la maladie au Danemark (Field cases of control of PMWS
in Denmark).
• Use of a polymerase chain reaction assay
and an ELISA to monitor porcine circovirus type 2 infection
in pigs from farms with and without post-weaning multisystemic
wasting syndrome.
• Quantification du génome du circovirus
porcin de type 2 (PCV2) par PCR en temps réel et corrélation
avec la maladie d’amaigrissement du porcelet (MAP) -
(Real time PCR quantification of porcine circovirus type 2
genome and correlation with post-weaning multisystemic wasting
syndrome).
• Epidemiologie moléculaire de circovirus
porcin (PCV2) en relation avec la maladie d’amaigrissement
du porcelet - (Molecular epidemiology of porcine circovirus
in relation with post-weaning multisystemic wasting syndrome).
• Effet de la génétique Piétrain
sur l’expression clinique de la maladie de l’amaigrissement
du porcelet (MAP) – Etude dans 4 élevages naisseurs-engraisseurs
- (Effect of the Pietrain breed on clinical post-weaning mulstisystemic
wasting syndrome – a cohort study in four farrow-to-finish
herds).
• Protection contre la maladie d’amaigrissement
du porcelet (MAP) par vaccins à ADN et protéines
recombinantes.
• Protection of swine against post-weaning
multisystemic wasting syndrome (PMWS) by porcine circovirus
type 2 (PCV2) proteins.
• Apoptosis and proliferative activity in
lymph node reaction in post-weaning multisystemic wasting
sindrome (PMWS).
• Susceptibility
of pig embryos to porcine circovirus type 2 infection.
• Reproduction of post-weaning multisystemic
wasting syndrome in pigs experimentally inoculated with a
Swedish porcine circovirus 2 isolate.
• Pulmonary aspergillosis in a post-weaning
multisystemic wasting syndrome (PMWS) affected pig.
• The economic impact of PMWS in the nursery.
• Association of porcine circovirus 2 with
porcine respiratory disease complex.
• Immunogenicity and pathogenicity of chimeric
infectious DNA clones of pathogenic porcine circovirus type
2 (PCV2) and nonpathogenic PCV1 in weaning pigs.
• Preface.
• Molecular biology of porcine circovirus:
analyses of gene expression and viral replication.
• Human circoviruses.
• The clinical expression and emergence of
porcine circovirus 2.
• Pathological findings associated with naturally
acquired porcine circovirus type 2 associated disease.
• Immunosuppression in post-weaning multisystemic
wasting syndrome affected pigs.
• Porcine circovirus-2 and concurrent infections
in the field.
• PMWS: experimental model and co-infections.
• Avian circovirus diseases: lessons for
the study of PMWS.
• Viremia and effect of fetal infection with
porcine viruses with special reference to porcine circovirus
2 infection.
• Effect of porcine parvovirus vaccination
on the development of PMWS in segregated early weaned pigs
coinfected with type 2 porcine circovirus and porcine parvovirus.
The
use of different vaccination schedules for sows to protect
piglets against Aujeszky’s disease.
CASAL J, PLANASDEMUNT L, VARO JA, MARTIN M
J Vet Med B, 51, 2004, 8-11
Three types of protocol were compared
: some sows were either vaccinated during pregnancy with an
inactivated vaccine, vaccinated during pregnancy with an attenuated
vaccine, or vaccinated during lactation with an attenuated
vaccine. At farrowing, the level of protection was assessed
in sows and piglets. Afterwards, five weaning piglets born
of each group of sows were challenged intranasally with a
neurotropic strain of Aujeszky’s disease virus (ADV).
Attenuated and inactivated vaccines conferred the same level
of protection to piglets born of sows vaccinated during pregnancy.
The highest level protection was indisputably achieved in
piglets born of sows vaccinated during pregnancy. As a consequence,
vaccinating the gilts three times before mating and successively
the sows one time during the second half of pregnancy appears
the best vaccination schedule to apply in order to control
Aujeszky’s disease.
Experimental
dual infection of pigs with an H1N1 swine influenza virus
(A/Sw/Hok/2/81) and Mycoplasma hyopneumoniae.
YAZAWA S, OKADA M, ONO M, FUJII
S, OKUDA Y, SHIBATA I, KIDA H
Veterinary Microbiology, 98, 2004, 221-228
http://www.sciencedirect.com
Keywords: swine influenza virus, H1N1, Mycoplasma hyopneumoniae,
dual infection.
This study was
carried out in caesarian derived colostrum deprived (CDCD)
pigs, which were either inoculated only with swine influenza
virus (SIV), inoculated only with M. hyopneumoniae
or dually inoculated. Dual infection was shown to significantly
increase the severity of the lesions caused by M. hyopneumoniae
alone.
PRRS
still a mystery.
MARTELLI P
Pig Progress Vol.19, N° 9, 2003, 10-11
Porcine reproductive and respiratory
syndrome virus still remains an odd pathogen which scarcely
ever abides by the common rules linked to infectious diseases.
The usual means of control lack efficacy and several characteristics
of PRRSV hamper attempts to that effect: a high degree of
genetic and antigenic diversity among field isolates, the
possible co-existence of several strains within the same herd
and lack of cross-protection, the ability of the virus to
induce persistent infection and remain undetectable by means
of a diagnostic test. Furthermore, several co-factors can
increase the expression of the PRRS, i.e. bacterial endotoxins
(LPS), various pathogens involved in porcine respiratory disease
complex (PRDC) and porcine circovirus type 2 (PCV2). In spite
of all this, a reduction of the impact of PRRS can be achieved
using currently available vaccines.
Evaluation
of the role of mallard ducks as vectors of porcine reproductive
and respiratory syndrome virus.
TRINCADO C, DEE S, ROSSOW K, PIJOAN C
Veterinary Record, February 21, 2004, 154, 233-237
Close contact between
pigs and ducks did not allow the transmission of PRRSV, either
from pigs to ducks or from ducks to pigs.
Porcine
reproductive and respiratory syndrome (PPRS) virus –
an update.
DONE SH
The Pig Journal, 52, 2003, 206-233
Practical review of the latest
literature regarding all aspects of PRRSV: interaction with
various co-factors, identification methods, pathogenesis,
reproductive manifestations, immune response, transmission,
diagnostic methods, available vaccines and control strategies.
Association
of porcine circovirus 2 with porcine respiratory disease complex.
KIM J, CHUNG HK, CHAE C
The Veterinary Journal, 166, 2003, 251-256
Keywords: pneumonia porcine circovirus, porcine respiratory
disease complex, prevalence.
In this study, 105 PRDC-affected
pigs were investigated for the presence of PCV2 and other
viral and bacterial pathogens. Most of these pigs were infected
by more than one pathogen. PCV2 was detected in 81% of the
cases which represents the highest prevalence among viral
pathogens (PRRSV 62.9%, parvovirus 57.1% and SIV 13.3%). In
55% of the cases, PCV2 and PRRSV were detected concurrently.
Furthermore, PCV2 resulted associated with Pasteurella multocida
and Mycoplasma hyopneumoniae in 44.7% and 38.8% of the cases
respectively. Even if the exact role of PCV2 is not understood
yet, it is likely to be greatly involved in PRDC.
Post-weaning
Multisystemic Wasting Syndrome in Asia.
TOO H, SENEQUE S
Asian Pork Magazine, December 2003/January 2004, 28-31
Following a brief review of the
main characteristics of post-weaning multisystemic wasting
syndrome (PMWS) and porcine dermatitis and nephropathy syndrome
(PDNS) the epidemiological situation of these two diseases
in Asia is described and reveals that both are widespread
and cause heavy loss in the Asian pig population. Besides,
the publication of the fourth “white book” on
PMWS by Merial is notified and recommended as a source of
up-to-date findings on the disease as well as on the situation
in Asia.
La
MAP: où en est-on ? (PMWS : where are we up to ?)
MADEC F
L’Europe face à la MAP (Europe facing PMWS),
Rencontres Internationales de Pathologie Porcine à
Loudéac (2004), 63-65
Since the first
description of PMWS in France in 1996, the situation has improved
a lot and the acute form of the disease has disappeared. The
multifactorial and still woolly aspect of pathogenesis of
the disease has led French pig practitioners to act primarily
on the environment of the pigs providing them with better
zootechnical conditions by minimizing stress and improving
hygiene conditions (Madec’s 20 control measures).
Cas
concrets de maîtrise de la maladie en Espagne (Field
cases of control of PMWS in Spain).
MARCO E
L’Europe face à la MAP (Europe facing PMWS),
Rencontres Internationales de Pathologie Porcine à
Loudéac (2004), 67-82
This paper first reviews
the control measures that can be applied to reduce the impact
of PMWS through herd management (reducing stress, improving
hygiene conditions, applying all-in/all-out, etc.), alimentation
(adding to feed bioflavonoids, vitamin E, selenium, antioxidants),
genetics (some breed, e.g. Pietrain, would be less susceptible
to PMWS), therapeutic treatments (serum therapy, aspirin)
and herd immune status (understood as improved and stable
overall immunity within the herd). Then, a particular emphasis
is put on the lesion of myocarditis found in PMWS-affected
pigs since this type of lesion is not consistent with PCV2-infection
which does not occur early enough to induce such a lesion
and since it is not found in experimentally infected pigs.
This suggests that some other causal agent may predispose
pigs to PCV2 infection.
Cas
concrets de maîtrise de la maladie en Italie : deux
cas cliniques différents (Field cases of control of
PMWS in Italy: two different clinical cases).
GHERPELLI M
L’Europe face à la MAP (Europe facing PMWS)
Rencontres Internationales de Pathologie Porcine à
Loudéac (2004), 83-91
Two field cases
of PMWS are reported. The early form of the disease occurs
in pigs of 6-7 weeks of age and induces particularly acute
clinical signs while the late form of the disease affects
pigs of 9-10 weeks of age and is characterized by more varied
and less acute clinical signs and represents the form more
frequently observed in Italy. The early form of PMWS affects
herds with an unstable PRRS status, the situation does not
improve through the implementation of Madec’s 20 control
measures, but does improve if early vaccinations are suppressed.
The late form of PMWS occurs in more PRRS-stable herds, the
implementation of Madec’s control measures greatly improves
the situation and early vaccinations do not have any influence.
The author underlines the fact that distinct conditions bring
about either one form of the disease or the other and that
it is necessary to adapt the control measures in each case.
Cas
concrets de maîtrise de la maladie au Danemark (Field
cases of control of PMWS in Denmark).
DALBY K
L’Europe face à la MAP (Europe facing PMWS),
Rencontres Internationales de Pathologie Porcine à
Loudéac (2004), 93-103
PMWS was first reported
in Denmark in 1999 and is now present in 30% of Danish swine
herds. The disease is responsible of heavy economic loss due
to high mortality rates reaching 20% and wasting. Madec’s
control measures of which especially colostrum intake, reduction
of mixing and improved management, were implemented. Providing
vitamin E at weaning, improving disinfection, using more gentle
vaccines and eliminating affected animals are additional measures
than can improve the situation. Genetics may play a role as
well since Hampshire Duroc crossbreeds seems to be more resistant
to PMWS. In Denmark, serum therapy is not authorized by law,
but studies carried out by Dalby out of Denmark have given
interesting results. However, this technique remains quite
laborious.
Use
of a polymerase chain reaction assay and an ELISA to monitor
porcine circovirus type 2 infection in pigs from farms with
and without post-weaning multisystemic wasting syndrome.
SIBILA M, CALSAMIGLIA M, SEGALES J, BLANCHARD P,
BADIELLA L, LE DIMNA M, JESTIN A, DOMINGO M
AJVR, Vol. 65, N°1, 2004, 88-92
A total of 495
pigs were included in this study, 236 of them were from PMWS-affected
herds while the remaining ones were from farms without PMWS.
Serum samples were submitted to ELISA detection for antibodies
to PCV2 and both serum samples and nasal swabs were submitted
to PCR analysis for PCV2 DNA. Interestingly, viremia and serum
antibodies to PCV2 were detected in both PMWS-affected and
non-affected farms confirming a high prevalence of PCV2 infection
in swine herds and supporting the idea that full expression
of PMWS requires other factors than infection with PCV2.
Quantification
du génome du circovirus porcin de type 2 (PCV2) par
PCR en temps réel et corrélation avec la maladie
d’amaigrissement du porcelet (MAP) - (Real time PCR
quantification of porcine circovirus type 2 genome and correlation
with post-weaning multisystemic wasting syndrome).
BLANCHARD P, LOIZEL C, BAUDOUARD MA, NIGNOL AC, GRASLAND
B, DORY D, CARIOLET R, JESTIN A
Journées Recherche Porcine en France, 36, 2004,
327-332
New reliable technique
for PCV2 quantification based on TaqMan methodology. The results
obtained with tissue samples from pigs with PMWS compared
with those from pigs without PMWS confirm that a high viral
load, about 1011 copies per gram of tissue sample, is required
to induce the expression of PMWS.
Epidemiologie
moléculaire de circovirus porcin (PCV2) en relation
avec la maladie d’amaigrissement du porcelet - (Molecular
epidemiology of porcine circovirus in relation with post-weaning
multisystemic wasting syndrome).
DE BOISSESON C, BEVEN V, BIGARRE L, THIERY R, ROSE
N, EVENO E, MADEC F, JESTIN A
Journées Recherche Porcine en France, 36, 2004,
333-338
Both PCV1 and
PCV2 were investigated farms with or without PMWS in Brittany
(France). PCV1 was not detected in any of the farms while
PCV2 was detected in 100% of PMWS-affected farms and in 76%
of PMWS-non-affected farms. Thirty-eight PCV2 isolates were
sequenced and 23 new variants showing 94.6 to 99.9 % nucleotide
identity were identified. No virulence molecular marker was
identified in PCV2 isolates from PMWS-affected farms. Thus,
PMWS outbreaks in Brittany are not to ascribe to the emergence
of a new genotype of PCV2 but rather to still unknown triggering
factors.
Effet
de la génétique Piétrain sur l’expression
clinique de la maladie de l’amaigrissement du porcelet
(MAP) – Etude dans 4 élevages naisseurs-engraisseurs
- (Effect of the Pietrain breed on clinical post-weaning mulstisystemic
wasting syndrome – a cohort study in four farrow-to-finish
herds).
ROSE N, ABHERVE-GUEGUEN G, EVENO E, JOLLY JP, BLANCHARD
P, OGER A, JESTIN A, MADEC F
Journées Recherche Porcine en France, 36, 2004,
339-344
Pigs born of a Pietrain
boar and pigs born of common boars were followed from birth
to slaughter to study the potential effect the Pietrain breed
on the expression of PMWS. The results of this study are in
disagreement with some observations made by swine practitioners
since no protective effect of the Pietrain breed was demonstrated.
On the contrary, the likely role of parvovirus in PMWS pathogenesis
was underlined: parvovirus infection in dams significantly
increased the risk of PMWS in the offspring. On the other
hand, low colostrums supply seems to be a clear predisposing
factor for the expression of PMWS.
Protection
contre la maladie d’amaigrissement du porcelet (MAP)
par vaccins à ADN et protéines recombinantes.
Journées Recherche Porcine, 36, 2004,
345-352
Protection of swine against post-weaning multisystemic
wasting syndrome (PMWS) by porcine circovirus type 2 (PCV2)
proteins.
Vaccine, 21, 2003, 4565-4575
BLANCHARD P, MAHE D, CARIOLET R, KERANFLEC’H A, BAUDOUARD
MA, ALBINA E, JESTIN A
Two vaccination
trials based on the use of two major proteins (ORF1-encoded
replication protein and ORF2-encoded capsid protein) of PCV2
were carried out. The approach consisted in associating a
DNA vaccine and a subunit vaccine. The DNA vaccine was made
of a plasmid containing ORF1 and/or ORF2 and a plasmid encoding
GM-CSF (granulocyte macrophage colony stimulating factor)
which serves as natural adjuvant. The subunit vaccine contained
replication and/or capsid proteins and an adjuvant (Montanide).
In the first protocol, pigs received a first injection of
DNA vaccine followed 2 weeks later by a second injection of
DNA vaccine and subunit vaccine. Weight gain, and the presence
of fever and lesions were used as parameters to assess the
efficacy of vaccination after challenge. ORF2-encoded capsid
protein showed more immunogenicity compared to ORF1-encoded
replication protein and provided a good level of protection
against PCV2 infection. In the second protocol the efficacy
of the DNA vaccine was compared to that of the subunit vaccine.
The subunit vaccine induced a better protection than the DNA
vaccine. Besides, PCV2 replication appeared to vary according
to the type of vaccine, suggesting that the type of immune
response may have an influence on the expression of PMWS.
Apoptosis
and proliferative activity in lymph node reaction in post-weaning
multisystemic wasting sindrome (PMWS).
MADRIOLI L, SARLI G, PANARESE S, BALDONI S, MARCATO
PS
Veterinary Immunology and Immunopathology, 97, 2004, 25-37
http://www.sciencedirect.com
Keywords: pig, PCV2, lymph mode, lymphoid depletion, apoptosis,
cell proliferation.
Lymphocyte depletion
in lymphoid tissues is one of the histological hallmark of
PMWS. The evaluation of proliferative activity and apoptosis
showed that cell depletion in lymph nodes is due to decreased
cell proliferation rather than increased apoptosis.
Susceptibility
of pig embryos to porcine circovirus type 2 infection.
MATEUSEN B, SANCHEZ RE, VAN SOOM A, MEERTS P, MAES
DGD, NAUWYNCK HJ
Theriogenology, 61, 2004, 91-101
http://www.sciencedirect.com
Keywords: PCV2, porcine embryos, zona pellucida.
The ability of
PCV2 to infect embryonic cells of in vivo produced porcine
embryos with or without zona pellucida (ZP) was investigated.
PCV2 was able to replicate in ZP-free morulae and blastocysts
and embryonic cells of more advanced stage of development
appeared more susceptible to the virus. By contrast, ZP-intact
embryos were resistant to PCV2 infection. However, given the
diameter of the ZP channels compared to that of PCV2 particles,
the protection provided by the ZP may not be complete.
Reproduction
of post-weaning multisystemic wasting syndrome in pigs experimentally
inoculated with a Swedish porcine circovirus 2 isolate.
ALLAN G, MCNEILLY F, MEEHAN B, MCNAIR I, ELLIS J,
KRAKOWKA S, FOSSUM C, WATTRANG E, WALLGREN P, ADAIR B
J Vet Diagn Invest, 15, 2003, 553-560
To date, despite the
presence of PCV2 in Swedish swine herds, no cases of PMWS
have been reported in Sweden. In order to understand this
phenomenon, an isolate of PCV2 obtained from a Swedish pig
necropsied in 1993, thus before the beginning of PMWS outbreaks
in the USA and in Europe, and that had no clinical disease
nor histological lesions, was inoculated to colostrum-deprived
(CD) pigs from a Northern Ireland herd. A complete reproduction
of PMWS was achieved. As a consequence, the emergence of PMWS
is very unlikely to be due to the introduction of a new pathogenic
strain and the status of the pigs and their environment are
confirmed as critical factors for the expression of PMWS following
PCV2 infection.
Pulmonary
aspergillosis in a post-weaning multisystemic wasting syndrome
(PMWS) affected pig.
SEGALES J, DOMINGO M, COLLEL M, JENSEN HE, BLANCO
JL
The Pig Journal, 52, 2003, 41-47
Pulmonary and
systemic aspergillosis is very rare in mammals. The occurrence
of pulmonary aspergillosis in a PMWS-affected finishing pig
is thus an additional element to confirm the immunosuppressive
effect of PMWS.
The
economic impact of PMWS in the nursery.
HARDGE T, GAUMANN H, HASBERG W, LANGE S
International Pig Topics, Vol. 18, N°8, 11-12
The overall cost of a
PMWS outbreak in an off-site nursery was determined by means
of data about weight gain, mortality due to PMWS or secondary
infections and veterinary interventions. The pre- and post-PMWS
periods were compared to the PMWS period. During the outbreak,
the gross margin was reduced by 3.9 and 4.1€ per pig
compared to the pre- and post-PMWS periods respectively. In
this case, the applied control strategies consisted in 1)
the optimization of the vaccination program for PRRS: vaccination
was anticipated from the 4th to the 3rd week of life so as
to avoid concomitant PCV2 circulation and vaccination and
allow piglets to reach a suitable level of immunity before
their introduction into the nursery farm, 2) the reduction
of pig-to-pig contact through the all-in/all-out method, 3)
Disruption of infection chains for secondary pathogens such
as Streptococcus suis with major care taken for removal
of teeth and tails, 4) improvement in the management of the
replacement gilts which were then purchased from only one
producer. This approach allowed to reduce mortality and improve
performance in the post-PMWS period.
Association
of porcine circovirus 2 with porcine respiratory disease complex.
KIM J, CHUNG HK, CHAE C
The Veterinary Journal, 166, 2003, 251-256
Keywords: pneumonia porcine circovirus, porcine respiratory
disease complex, prevalence.
In this study,
105 PRDC-affected pigs were investigated for the presence
of PCV2 and other viral and bacterial pathogens. Most of these
pigs were infected by more than one pathogen. PCV2 was detected
in 81% of the cases which represents the highest prevalence
among viral pathogens (PRRSV 62.9%, parvovirus 57.1% and SIV
13.3%). In 55% of the cases, PCV2 and PRRSV were detected
concurrently. Furthermore, PCV2 resulted associated with Pasteurella
multocida and Mycoplasma hyopneumoniae in 44.7%
and 38.8% of the cases respectively. Even if the exact role
of PCV2 is not understood yet, it is likely to be greatly
involved in PRDC.
Immunogenicity
and pathogenicity of chimeric infectious DNA clones of pathogenic
porcine circovirus type 2 (PCV2) and nonpathogenic PCV1 in
weaning pigs.
FENAUX M, OPRIESSNIG T, HALBUR PG, MENG XJ
Journal of Virology, October 2003, 11232-11243
The immunogenic ORF2
capsid gene of PCV2 was substituted for that of the non-pathogenic
PCV1. This chimeric PCV1-2 replicated and expressed the capsid
protein of PCV2 in vitro and in vivo. The capsid protein was
immunogenic but the infection with the chimeric PCV1-2 induced
only a limited infection with mild pathological lesions. Further
studies are required to determine whether this type chimeric
virus could be used in future as a vaccine against PCV2 infection
and PMWS.
Preface.
JESTIN A
Veterinary Microbiology, 98, 2004, 79-80
http://www.sciencedirect.com
Introduction to
the special issue of Veterinary Microbiology which contains
the keynote lecture presented at the first ssDNA Comparative
Virology Symposium held in Saint-Malo, France, on 24-27 September
2001 under the auspices of the European Society for Veterinary
Virology (ESVV). PMWS and PCV2 aroused particular interest.
Molecular
biology of porcine circovirus: analyses of gene expression
and viral replication.
MANKERTZ A, ÇALISKAN R, HATTERMANN K, HILLENBRAND
B, KURZENDOERFER P, MUELLER B, SCHMITT C, STEINFELDT T
Veterinary Microbiology, 98, 2004, 81-88
http://www.sciencedirect.com
Keywords: Porcine circovirus, replication, gene expression.
Following a description of the
genome organization of circoviruses focused on the cap gene
and the rep gene, the analysis of the function of the 2 proteins,
Rep and Rep’, encoded by PCV1 rep gene is reported.
A replication assay was performed and showed that PCV1 Rep
and Rep’ replicated the origin of both PCV1 and PCV2.
Human circoviruses.
BIAGINI P
Veterinary Microbiology, 98, 2004, 95-101
http://www.sciencedirect.com
Keywords: circovirus, TT virus, TLMV.
Circoviruses are
also present in the human species: the TT virus (TTV) and
TTV-like minivirus (TLMV), discovered in 1997 and 1999 respectively,
are both frequently detected in various body fluids. To date,
both are considered as being non-pathogenic.
The
clinical expression and emergence of porcine circovirus 2.
HARDING JCS
Veterinary Microbiology, 98, 2004, 131-135
http://www.sciencedirect.com
Keywords: porcine circovirus, post-weaning multisystemic wasting
syndrome, porcine dermatitis nephropathy, proliferative necrotizing
pneumonia, congenital tremors, myocarditis.
A review on PCV2, its
clinical expression and its role in various disease syndromes:
PMWS, PDNS, reproductive failure, PNP, congenital tremors
Pathological
findings associated with naturally acquired porcine circovirus
type 2 associated disease.
SEGALES J, ROSELL C, DOMINGO M
Veterinary Microbiology, 98, 2004, 137-149
http://www.sciencedirect.com
Keywords: porcine circovirus type 2, necropsy, histopathology,
immunohistochemistry, in situ hybridization, post-weaning
multisystemic wasting syndrome.
A review on the
gross, microscopic and ultrastrutural pathology of PCV2 and
its involvement in PMWS, PDNS, reproductive failure, PRDC,
PNP, congenital tremors. A brief description of the detection
methods for PCV2 is also included.
Immunosuppression
in post-weaning multisystemic wasting syndrome affected pigs.
SEGALES J, DOMINGO M, CHIANINI F, MAJO NATALIA, DOMINGUEZ
J, DARWICH L, MATEU E
Veterinary Microbiology, 98, 2004, 151-158
http://www.sciencedirect.com
Keywords: immunosuppression, porcine circovirus type 2, post-weaning
multisystemic wasting syndrome, immunopathology, flow cytometry.
Several findings lead
to hypothesize the immunosuppressive effect of PMWS, either
from a clinical point of view (litter effect, co-infections,
etc.), from the histopathological features of the disease
and the changes in peripheral blood mononuclear cell (PMBC)
subsets. However, the exact role of PCV2 in the impairment
of the immune system needs to be further investigated.
Porcine
circovirus-2 and concurrent infections in the field.
ELLIS J, CLARK E, HAINES D, WEST K, KRAKOWKA S, KENNEDY
S, ALLAN GM
Veterinary Microbiology, 98, 2004, 159-163
http://www.sciencedirect.com
Keywords: porcine circovirus, co-factors, co-infections.
When reviewing
the various swine diseases that currently affect the world’s
swine populations, the prevalence of PCV2 co-infection is
a striking fact. However, the synergism between PCV2 and porcine
parvovirus (PPV) which may enhance PCV2 replication but does
not result necessary for the development of PMWS, the synergism
between PCV2 and porcine reproductive and respiratory syndrome
virus (PRRSV), Mycoplasma hyopneumoniae or swine
influenza virus (SIV) which are frequently reported as co-factors
in porcine respiratory disease complex (PRDC), as well as
the involvement of PCV2 in hepatic, enteric and renal diseases
are not fully understood. An hypothesis is that co-infecting
agents would cause the death of cells leading to the regeneration
of damaged tissue and an increase of the actively replicating
cell population used by PCV2 to replicate. This would result
in an increase of the viral load and the expression of the
disease. Besides, an increased occurrence of parasitosis (Pneumocystis
carinii) in PMWS-affected pigs indicates a potential
immunosuppressive effect of PCV2 infection.
PMWS:
experimental model and co-infections.
ALLAN GM, MCNEILLY F, ELLIS J, KRAKOWKA S, BOTNER
A, MCCULLOUGH K, NAUWYNCK H, KENNEDY S, MEEHAN B, CHARREYRE
C
Veterinary Microbiology, 98, 2004, 165-168
http://www.sciencedirect.com
Keywords: porcine circovirus, experimental infection, wasting.
The results of experimental
infections of gnotobiotic (GN), colostrum-deprived (CD) and
colostrum-fed pigs with PVC2 (CF) with PCV2 are reviewed.
PMWS was reproduced with the inoculation of PCV2 alone. Co-infections
and immunostimulation were demonstrated to increase the severity
of the disease, suggesting that PCV2 may take advantage of
the presence of an increased actively replicating cell population
to replicate.
Avian circovirus
diseases: lessons for the study of PMWS.
TODD D
Veterinary Microbiology, 98, 2004, 169-174
http://www.sciencedirect.com
Keywords: circoviruses, avian circoviruses, porcine circovirus,
pigeon circovirus, goose circovirus, BFDV, CAV, PMWS.
The common features
of psittacine beak and feather disease virus (BFDV), pigeon
circovirus (PiCV), goose circovirus (GoCV) and porcine circovirus
type 2, all members of the genus Circovirus of the
family Circoviridae are reviewed. The study of these
avian circoviruses could provide valuable and applicable information
in the areas of diagnosis, epidemiology pathogenesis and disease
control for PMWS so could the more investigated chicken anemia
virus (CAV) even if perhaps less directly.
Viremia
and effect of fetal infection with porcine viruses with special
reference to porcine circovirus 2 infection.
PENSAERT MB, SANCHEZ RE, LADEKJÆR-MIKKELSEN
AS, ALLAN GM, NAUWYNCK HJ
Veterinary Microbiology, 98, 2004, 175-183
http://www.sciencedirect.com
Keywords: porcine circovirus type 2, viremia, sows, fetus.
The pathogenesis of transplacental
infections with porcine viruses in sows is briefly reviewed,
followed by a comprehensive report of the results of several
experiments of PCV2 infection in pregnant sows. PCV2 was shown
to cause viremia. Both the cell-free and PMBC-associated forms
of viremia were demonstrated but the PMBC-associated form
is largely more prominent and long-lasting. In addition, PCV2
was shown to cause fetal pathology and death without affecting
the maternal physiology and pregnancy. The heart is likely
to be the primary target organ once PCV2 has entered fetuses.
Intra-uterine virus spread was found to occur rather slowly.
Effect of
porcine parvovirus vaccination on the development of PMWS
in segregated early weaned pigs coinfected with type 2 porcine
circovirus and porcine parvovirus.
OPRIESSNIG T, FENAUX M, YU S, EVANS RB, CAVAMAUGH
D, GALLUP JM, PALLARES FJ, THACKER EL, LAGER KM, MENG XJ,
HALBUR PG
Veterinary Microbiology, 98, 2004, 209-220
http://www.sciencedirect.com
Keywords: porcine circovirus type 2, porcine parvovirus, post-weaning
multisystemic wasting syndrome, vaccination.
In this study,
the clinical expression of PMWS was more severe in PCV2/PPV
co-infected pigs than in the PCV2-single-infected pigs which
did not develop any clinical sign. In contrast to the results
of field studies, this experimental study did not show neither
protection against clinical PMWS nor reduction of the severity
of lymphoid depletion in PCV2/PPV co-infected pigs with the
use of vaccination against PPV.
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