Erysipelas Outbreak in Sows on a 1000 Sow
Farrow-to-Finish Farm
An outbreak of acute Erysipelas was diagnosed in sows housed
in a single gestation barn on a commercial 1000 sow farrow-to-finish
farm. This case report highlights Erysipelas as a continuing
threat to intensively reared swine housed in entirely environmentally-controlled
housing.
A swine herdsman observed classic red diamond shaped lesions
on the skin of four sows in the same gestation barn. The
sows were lame and lethargic. He immediately called his
veterinarian.
A review of records revealed that all four sick animals
had either recently shared a gestation pen or were serviced
by a common boar and that the sows were 10 to 18 months
of age. Clinical examination revealed polygonal dark red
to purple, sometimes raised lesions on the skin of the dorsum
and hams. All animals were reluctant to walk and favored
one or more limbs when walking. Rectal temperatures ranged
from 103.5-106.5F. Careful examination of other animals
in the herd revealed no other affected animals. Because,
in addition to Erysipelas, diamond skin lesions have also
been reported with septicemia caused by Actinobacillussuis,
blood for culture was collected from each sow directly into
blood culture bottles containing tripticase-soy broth (Bacto
Blood Culture Bottles, Difco).Erysipelothrixrhusiopathiae
was isolated from the blood in two of the four sows. Therapeutic
doses of penicillin were administered intramuscularly
for three consecutive days to the four sick animals, all
pen-mates of the sick animals and all boars that had recent
contact with the sick animals. The herdsman was instructed
to watch other animals closely for evidence of acute or
chronic Erysipelas. Also, it was recommended that the four
sick animals should be sold to market after appropriate
antibiotic withdrawal times because of the potential for
the development of chronic arthritic Erysipelas. All four
sick animals responded to antibiotic therapy. No other animals
developed acute Erysipelas and there has been no recurrence
in the nine months since the outbreak.
A review of the vaccination program for females in this
herd revealed no obvious omissions. When gilts entered the
herd at five to six months of age, they were vaccinated
with a combination vaccine or Erysipelas, parvovirus
and Leptospirosis. When they were successfully mated, usually
within one to five weeks, they received a booster vaccination.
At weaning, all sows that would remain in the breeding herd
received a booster vaccination for Erysipelas and
Leptospirosis. Boars were not vaccinated. It was recommended
that all boars be vaccinated twice annually for Erysipelas
and Leptospirosis. Also, methods used for vaccination were
reviewed to ensure that all animals were vaccinated correctly,
records were kept of vaccinations, vaccines were stored
correctly and needles and syringes were cleaned and disinfected
between uses.
The cause of this outbreak was not clear. There was no
previous history of Erysipelas in this herd. It is possible
that one of the unvaccinated boars was shedding E.rhusiopathiae
and that some of the exposed females were susceptible due
to missed vaccinations, poor vaccination technique or poor
response to vaccination. The source of E. rhusiopathiae
in outbreaks of Erysipelas was previously thought to be
persistence in the soil;
however, more recent research has shown that it can remain
viable in soil for only 35 days under optimal conditions.
We now know that many healthy swine, some estimate 30-50%,
are tonsillarcarriers of E. rhusiopathiae. The organism
can be shed in oronasal secretions, urine and feces. Rodents
and birds can also serve as reservoirs. Spread of infection
in a swine herd is by close contact or by contaminated water,
feed or bedding.
The classic lesions of diamond-skin infarcts are highly
suggestive of Erysipelas; however, several facts need to
be considered in making a diagnosis of Erysipelas. Actinobacillussuis
can also cause an acute and fatal septicemia with cutaneous
infarcts. Also, in all outbreaks of Erysipelas, diamond
skin lesions may not be a prominent feature. Sometimes animals
are just found dead with no cutaneous lesions. Typical post-mortem
lesions in acute Erysipelas, in addition to cutaneous infarcts,
include slightly to moderately enlarged, "meaty"
spleens, mild pulmonary edema and renal cortical petechiae.
In chronic Erysipelas, polyarthritis with periarticiular
fibrosis and vegetative valvularendocarditis are the most
common lesions. Bacterial culture is required for confirmation.
From dead animals, lymph nodes, liver and spleen are excellent
tissues to culture. If you are doing your own bacteriology,
remember E. rhusiopathiae grows very slowly on blood
agar and colonies and/or typical green discoloration of
agar due to alpha-hemolysis may not be visible until 24-36
hours of incubation. Do not throw away your culture plates
too early!
This report serves as a reminder that modem herds are still
at risk for Erysipelas and clinical disease may only be
a "stress" or a missed vaccination away. Good
vaccination programs done according to label recommendations
should prevent Erysipelas. However, if an outbreak does
occur, aggressive targeted parenteral antibiotic therapy
is usually effective.
-DougScholz, Class of 1996
-Greg Stevenson, DVM.PhD
-Sandra Amass, DVM, MS
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