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POSTWEANING WASTING/CATABOLIC SYNDROME - CANADA: REQUEST FOR INFORMATION
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A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>
Date: 10 Feb 2010
Source: PortageOnline.com [edited]
<http://www.portageonline.com/index.php?option=com_content&task=view&id=15892&It emid=68>
Researchers at the [Canadian] Western College of Veterinary Medicine
are trying to determine the cause of a mystery disease appearing in
pigs. Dr. Yanyun Hyuang says they have very little understanding of
postweaning wasting/catabolic syndrome, or PWCS. He says the cause of
the disease is unknown, and their research shows it's not linked to
other common pig diseases such as PRRS and circovirus.
Hyuang explains the disease seems to affect perfectly healthy animals
in well-managed operations. Within 2 weeks of weaning, piglets who
previously appeared completely healthy demonstrate anorexia and
become thin and hairy. The presence of the disease increases
mortality of young pigs from 1-2 percent to 6-10 percent, as nearly
all the animals with PCWS die.
Hyuang says they know so little about the disease that he can't even
comment on how common it is as he fears he may underestimate its prevalence.
The disease has been found in barns in Manitoba, Saskatchewan,
Ontario and Kansas. It's estimated that up to 20 barns in Manitoba
are affected by PCWS.
--
Communicated by:
ProMED-mail
<promed@promedmail.org>
[This is a right puzzler that is increasing in incidence and impact
and is a multifactorial syndrome.
Postweaning multisystem wasting syndrome (PMWS) was 1st described in
1991 in Western Canada and has since become widespread in North
America and Europe. It produces slow progressive wasting in
postweaned pigs with usually a low attack rate but high case fatality
rate. Clinical signs and postmortem findings vary, with some pigs
jaundiced, some with diarrhea, but most with grossly enlarged
inguinal lymph nodes. Respiratory signs are often associated with
underlying interstitial pneumonia and pulmonary edema. The cause is
uncertain, but caused at least in part by porcine circovirus 2, which
is isolated from affected pigs, usually in association with porcine
reproductive and respiratory syndrome (PRRS). Clinical disease is
more common in high health herds, but pigs are often infected without
showing clinical disease. Cases of porcine dermatitis and nephropathy
syndrome (PDNS) are often seen in herds affected with PMWS
<http://medical-dictionary.thefreedic...wasting+syndro!
me>.
Workers (Luc Dufresne, DVM, Seaboard Foods; Thomas Fangman, DVM,
Boehringer Ingelheim Vetmedica, Inc., and Steve Henry, DVM, Abilene
(KS) Animal Hospital) in Kansas have noted 2 different patterns of
the syndrome, Dufresne adds. One is a high incidence of failure to
thrive with a high rate of colitis and pneumonia. "In these cases,
diagnostics implicate salmonella and rotavirus, and we suspect that
the failure to thrive was initiated by one or both of these
pathogens," he continues.
The use of vaccination, strategic antibiotic treatment and partial
depopulation has greatly reduced mortality in those flows. "Although
we have been successful at controlling the pathogens,
failure-to-thrive pigs remain, but at much lower levels," Dufresne counters.
In contrast, a different trend has emerged in the last year [2009] in
some of Seaboard's production flows. "Necropsy results shown in
Figure 3 indicate that failure to thrive is the 1st- or 2nd-highest
cause of mortality, with no major lesions of colitis or enteritis,"
he asserts. In these cases, the catabolic syndrome seems to play a
major role by itself. There appear to be 3 major clinical observations:
** The severity of the syndrome is sow-farm dependent. When pig
sources are combined in the same nursery barn, the prevalence of
failure-to-thrive pigs can be 4 to 5 times higher in one source vs. the others.
** Porcine reproductive and respiratory syndrome (PRRS) can be
involved, but not always. In one case, when 2 sow farms combined pigs
in nurseries in source-specific rooms, the syndrome results were
worse in the offspring coming from a PRRS-stable farm than the
offspring from a PRRS-unstable farm.
** Males are more affected than females. In farms experiencing this
syndrome, death loss in barrows is usually twice as high as in gilts.
In the necropsy audit results shown, out of 236 piglet necropsies,
152 were barrows and 84 were gilts.
The full text can be seen at:
<http://nationalhogfarmer.com/health-diseases/0915-researchers-trying-solve-syndrome/index1.html>.
See as well: "Potentiation of Porcine Circovirus 2-induced
Postweaning Multisystemic Wasting Syndrome by Porcine Parvovirus Is
Associated with Excessive Production of Tumor Necrosis Factor-Eo" J.
Kim, Y. Ha and C. Chae, Veterinary Pathology 43(5): 718-725, doi:
10.1354/vp.43-5-718; <http://vet.sagepub.com/content/43/5/718.full>. - Mod.MHJ]
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