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Contagious Ecthyma
Randall J. Berrier,
DVM
Staff Veterinarian
Technical Service
Contagious Ecthyma (also known as Orf,
Sore Mouth and Contagious Pustular Dermatitis)
is an infectious dermatitis of sheep and
goats. Oral (lip) lesions (scabs) are the primary clinical
findings at the mucocutaneous junction. Infections can also
occur on the coronets, ears, anus, vulva or prepuce. The
causative agent is a parapox virus. Man can occasionally
become infected if the virus (scab) contacts damaged skin.
Contagious Ecthyma can be seen anytime of
the year and affects mainly young animals, but can affect
mature sheep as well if they have had no previous immunity.
The disease is spread by direct contact. Morbidity can be >
70 - 80% of the flock but mortality is usually very rare
(< 5-15 %). Bad infections
usually cause unthriftiness and decreased feed consumption due
to the soreness of the lip lesions. Uncomplicated cases
usually recover in about three weeks.
The virus is highly resistant to
temperature and desiccation and can survive at room
temperature for greater than 15 years.
TREATMENT AND CONTROL (Vaccination):
Once detected in a flock, isolate the infected animals and
vaccinate the remainder. Mild cases require no treatment.
Treatment of more advanced cases involves nursing care, soft
food and antimicrobials for secondary bacterial infections. In
severe cases mild scrubbing of the lesions with betadine can
help, but care must be taken when applying topical medications
as this can be transmitted to people. Wear gloves and wash
hands well afterwards.
In endemic areas, vaccinate the lambs at 6
to 8 weeks, and vaccinate range lambs at least 2 to 3 weeks
before shipment to feed lots. In the event of an outbreak, you
can vaccinate uninfected lambs at a few days of age and
illicit some protective response. Pre-lamb vaccination of the
ewes does no good as there is no placental or colostral
antibody transfer to lambs.
Immunity after infection is for 2 to 3
years. Immunity from vaccination is about 2 years, but lambs
should be inspected 2 to 3 days after vaccination to ensure a
scab has formed.
Vaccination involves scarifying the inside
of the thigh or other wool-free area and brushing the
reconstituted vaccine into the scratched area. In 1 to 3 days
a scab will form – which is necessary to achieve an immune
response. Absence of a scab usually means either:
1) existence of prior immunity, or
2) poor application technique
Because the vaccine is of live virus
origin, use precautions and wear gloves.
It is important to note that the vaccine
will not prevent contagious ecthyma, but will greatly decrease
the severity and duration of the disease.
Colorado Serum Company is proud to provide
Ovine Ecthyma Vaccine to help reduce the
incidence of this disease. Please read the instructions from
the package insert when using this vaccine.
* Data on file
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