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Contagious
ecthyma:
An
unusual distribution
of
lesions
in goats
John
W. Coates,
Stein
Hoff
Contagious
ecthyma,
or orf, is
a
highly
contagious
_disease
of sheep
and
goats
which
is
caused
by
a
parapox
virus
(Family Poxviridae)
and
is
seen
throughout
the
world. Lesions
are
of
a
scabby
and
pustular
nature.
Traditionally,
the
disease
is
described
as
being
confined
to
the
muzzle and
lips
of
young
lambs
through
to
six months
of age,
although
adults
may also
at
times
be affected (1).
Occasionally,
affected
suckling
lambs
may
spread
the
disease
to
the
teats
and
udder of dams (1,2).
The
diagnostic
chal-
lenge
for the
practitioner
becomes
greater
when the
virus
strays
from its usual
distribution.
We
document
such
a case
in
this
report.
A
group
of
seven
female
Nubian
goats
was
exam-
ined
because of
multifocal
proliferative
skin lesions
over
the
head, neck,
chest,
and flanks
of each
animal.x
The
lesions
developed approximately
two
weeks
after
the
animals
returned
from
a
local
summer show,
at
which
the does had been housed for
three
days
in
pens
previously
occupied
by
sheep.
Despite
the
skin lesions,
the
animals did
not
appear
systemically
ill.
Bucks that
had also been
shown,
but
housed
in a
separate
barn,
were not
affected.
The
lesions
began
as
plaques, followed
by
epider-
mal
proliferation
and severe
encrustation.
Affected
areas
were
discrete,
approximately
2-7
cm
in
diameter
(Figures
1
and
2).
Lesions
were
not
pruritic,
or
only
mildly
so.
Affected
areas
were
initially
hyperemic,
gradually
becoming
more
pale
or
gray
in color
as
crusts
built
up
and
the
lesions
aged.
Lesions
were
not
observed
on
the
muzzle,
lips,
udder,
or
teats
of the
animals.
Differential
diagnoses
considered
were:
bacterial
skin
disease,
including
that
caused
by
Dermatophilus
congolensis; dermatophytosis;
ectoparasites;
and
viral
skin
disease,
particularly
contagious
ecthyma
or
orf,
as
well
as
other
poxviruses.
Cotnsabs
of
exudates
and
crusts
from
the
affected
areas
were
taken for
bacterial
and
fungal
culture,
as
well
as
scrapings
for
ectoparasites.
Skin
biopsies
were
Can
Vet
J
1990;
31: 209-210
_
.
-r
S
Figure
1.
Multiple
gray,
alopecic,
crusty
areas on the
neck
and
chest
wall.
Color
of
lesions
faded with
age.
Animal's
right ear at top
of
picture.
_;
.,
ZS
7b
Figure
2.
Close-up
of skin
showing
an
early
erythematous,
crusty
lesion.
Abbotsford
Animal Health
Centre,
1874
Gladwin
Road,
P.O.
Box
100, Abbotsford,
British
Columbia
V2S
4N8
(Coates); Squamish
Veterinary Services,
P.O.
Box
2139,
Squamish,
British
Columbia
VON
3GO
(Hoff).
Can Vet J
Volume
31,
March
1990
obtained
from
the
affected
areas
following
infiltration
with
a
local anesthetic
(Carbocaine
-V,
Winthrop Lab-
oratories, Aurora, Ontario).
Biopsies were
submitted
as
fresh
specimens
together
with
samples preserved
in
10Wo
buffered
formalinized
saline.
The
formalinized
skin
biopsies
were
processed
routinely and
stained
with
209
hematoxylin
and
eosin. Special stains
used on
the
pre-
pared
skin sections
were
Gram's
for
the
detection
of
bacteria,
and
periodic-acid-Schiff
(PAS) and Grocott's
for detection
of
fungi.
Skin sections
had
prominent
areas
of
orthokeratotic
and
parakeratotic hyperkeratosis.
There were many
neutrophils
within
an eroded
epidermis,
with
numer-
ous
subcorneal
pustules.
Epidermal
hyperplasia
with
prominent
rete
ridges
was
marked. Degenerative
changes
were
seen
within
the stratum spinosum,
with
numerous swollen,
vacuolated
cells having pyknotic
nuclei.
A
few
keratinocytes
contained large, eosino-
philic
intracytoplasmic
inclusion
bodies.
The super-
ficial
dermis
was
edematous
and hyperemic,
with
moderate
to
marked
aggregations
of
a
mixture
of
inflammatory
cells.
Dermatophilus
sp.
was not
dem-
onstrated
in Gram's
stains of tissue sections.
Fungi
were
not
apparent
in
Grocott's
or
PAS
stains.
Bacterial culture yielded
a
hemolytic
Staphylococcus
aureus
and
saprophytic
bacteria.
Mycotic
culture
yielded
only saprophytes.
Skin
scapings
were
negative
for
ectoparasites.
Poxvirus particles
consistent with
contagious
ecthyma
virus
(orf)
were
observed
in
elec-
tron
microscopic
studies of fresh scab material
from
lesions.
This outbreak
of
contagious
ecthyma involving
the
head, neck,
and
chest
was very
different
from
tradi-
tional
descriptions
of
the
disease because
lesions
were
not
found
on
the muzzle, lips,
teats,
or
udder
of the
seven
does
examined.
Other
cases
involving
unusual
lesion
distribution,
however,
have been
reported.
Contagious
ecthyma has been
described
in
a
buck
involving
the
scrotum,
belly,
and
legs
(3).
Other
reports
have
recorded
tail lesions
secondary
to
docking
in
sheep
(4)
or ear
tagging
(5).
The
common
factor
in
these
previous
reports
with unusual
lesion
distribution
is
exposure
to
the
virus via
inanimate
objects
previ-
ously
contaminated
by
infected animals.
In
our
case,
the
distribution
of
lesions
on
the head,
neck, and
flanks
of
the animals suggested
local
injury
and
penetration
of
the
skin
as
the
probable
portal
of
entry
by
the
organism.
The
development
of lesions
shortly
after
completion
of
the
show circuit
suggested
expo-
sure
to
this
environmentally
hardy
virus
(1,2)
at
that
time,
presumably
from the
sheep
that had
occupied
the
same
pen.
Contaminated objects
within
the
holding
pens,
such
as
sharp
fencing
wire,
nails,
or
staples,
or
even
bedding,
may
have
been
the
source
of virus. The
virus has
also been recorded
in
other
animals,
includ-
ing Bighorn sheep
(6),
Dall
sheep
and
musk-oxen
(7),
dogs
(8),
and
man
(9).
There
are
other
poxvirus
diseases
in
goats
and
sheep
that
must
be
considered
when
attempting
to
diagnose
the
causative
agent
of the
skin
lesions
seen
in
these
goats.
This
is
particularly
important
when
the
pres-
ence
of
a
foreign
poxvirus
is
a
possibility.
Differen-
tiation
from
these other
poxvirus
agents
was
based
on
the
morphology
of
lesions
observed and the
benign
nature
of
the
outbreak.
The
lesions
seen
in these
animals
were
proliferative in nature,
not
ulcerative
and
destructive
as in
ulcerative dermatosis,
another pox-
virus of
sheep
(1,2).
Ulcerative
dermatosis
is
known
to
occur
in
South
Africa,
the
United
Kingdom,
and
the
United
States (10).
The
ulcerating
lesions seen
in
that
disease have
been
observed
on
the
lips,
face,
legs,
vulva,
prepuce,
and glans
penis
of
affected animals
(10).
Goatpox virus, closely related
to
the very
pathogenic
sheeppox,
is
described
as
being milder than
the
latter, though the
mortality
rate may vary from
50o
to
100%
(2). Sheeppox virus is exotic
to
North
America. Under natural
conditions, no other
species
of
animals, including goats,
develop
sheeppox
(10).
The
goats
affected
by this
unusual
distribution
of
lesions
recovered
uneventfully
within three
to six
weeks
without
treatment.
The skin crusts
gradually
dried and
fell
off,
leaving
alopecic and
depigmented
skin.
Regrowth of
hair
followed,
although
pigmentation
of
the
new
hair
was
darker
than
normal.
Following
the
initial
outbreak
in
this
group of
does,
no
other
animals
in
the goat
herd
were
affected. Additional
cases, with
the
potential
for more
severe
consequences
due
to
immunological
naivety,
might have been
expected
in
other
goats
on the
farm
if
an
exotic poxvirus had
actually
been introduced.
It is
certainly
possible
that similar
outbreaks
of
contagious
ecthyma
in
goats
with
an
aberrant
distribu-
tion of
lesions have occurred
elsewhere in the past.
Such marked
variations
present
a
novel
diagnostic
challenge
to
the
practitioner.
The
results
obtained
in
this
case
clearly
demonstrate the value
of
submitting
adequate
fresh
and
fixed
biopsy
material
to the
labo-
ratory
to
facilitate
the accurate
diagnosis of skin
disease
of
uncertain
etiology.
From
the
zoonotic
point
of view,
there is
an
increased
hazard
to
the
owner
and
veterinarian
alike unless the true nature
of
such
skin
disease
is clearly
differentiated
from other
dermatopathies.
cvi
References
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Blood
DC,
Radostits OM.
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Medicine. 7th
ed.
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Bailliere
Tindall,
1989:
945-948.
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Jubb
KVF,
Kennedy
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Thompson
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Can Vet
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31,
March
1990
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