Contagious Ecthyma
Dr. Md. Mahbub Alam
Professor
Department of Medicine
Contagious Ecthyma
Syn: Orf, Sore mouth, Scabby Mouth
Contagious Pustular Dermatitis Contagious
Pustular Stomatitis Infectious Labial
Dermatitis
Overview
• History
• Organism
• Epidemiology
• Transmission
• Disease in Animals
• Prevention and Control
• Disease in Humans
Definition
• Contagious ecthyma is an infectious
dermatitis of sheep and goats that
affects primarily the lips of young
animals. The disease is usually more
severe in goats than in sheep. People are
occasionally affected through direct
contact.
History
• Orf described in animals
– Sheep: 1787
– Goats: 1879
• Orf described
in humans
– 1923
The Organism
• Genus Parapoxvirus
– Family Poxviridae
– Parapoxvirus is related to pseudocowpox and bovine
papillar stomatitis.
• Viability
– One month on wool/hides
after the lesions have healed
– Up to 12 years in lesion crusts
• Resistant: Very resistant to inactivation in environment. In
the laboratory, it is also resistant to glycerol and to ether.
EPIDEMIOLOGY
Geographic Distribution
• Worldwide distribution and is
common in goat and sheep-
raising countries.
• In the U. S. this disease is most
often seen in western states.
• 40% of U.S. sheep are affected.
Host/Species Affected
• Sheep • Deer
• Goats • Prong-horn antelope
• Camels • Rare cases in Dogs
• Bighorn sheep – Ingestion of
infected carcasses
Age susceptability
• Young animals are • It can be seen any time
generally more of the year and affects
susceptible than adults. immature animals but
• Human can also be can also affect mature
infected. sheep and goats.
Center for Food Security and
Public Health, Iowa State
University, 2012
Transmission
• This disease is transmitted by direct
contact through skin wounds and
abrasions; also fomites
• Human can be infected by handling of
infected animals
Clinical signs
1. The incubation period: 2 to 3 days.
2. The initial signs are papules, pustules, vesicles and scab
formations
3. Found on the lips, nose, ears and/or eyelids, and
sometimes on the feet or perineal region.
4. Lesions can also occur inside the mouth, particularly in
young lambs.
5. Rarely, the lesions may extend into the esophagus,
stomach, intestines or respiratory tract.
Clinical Signs
6. Nursing lambs can transmit the virus to their
dam, resulting in lesions on the teats and udder
7. Thick, brown, rapidly growing scabs over areas
of granulation,inflammation and ulceration.
8. The scabs are often friable and bleed easily.
9. Contagious ecthyma lesions are painful and
may result in anorexia or even starvation.
10. Foot lesions can cause lameness.
11. Uncomplicated infections usually resolve in 1
to 4 weeks.
12. Secondary bacterial infections and maggot
infestations can occur.
13. Contagious ecthyma may predispose animals
to bacterial mastitis.
14. More severe infections have been described in
Boer and Boer cross goats in which severe
proliferative dermatitis accompanied by chronic
pneumonia, arthritis and lymphadenopathy.
Diagnosis
• Diagnosed depends on- Clinical history and
Clinical signs.
• For Confirmation
– Electron microscopy (scabs)
– PCR
• Other tests (less common)
– Virus isolation
– Serology
– ELISA, FAT & Immuno diffusion test
Center for Food Security and Public
Health, Iowa State University, 2012
Treatment
• No specific treatment
• Supportive care
– Wound dressing
– Local antiseptics/Astringent/ZnSo4
– Whitefield ointment & tube feeding.
• Fly repellents
• Antibiotics for secondary infections
• Diathermy and cryosurgery have been used to
treat intraoral lesions in lambs but may not be
economical.
Prevention in Animals
• Quarantine new animals
• Keep equipment/fomites clean
• Vaccination for healthy animals
– Live virus vaccine is used
• Lambs should be vaccinated at 6-8 wks of age
• Difficult to eradicate
DISEASE IN HUMANS
Clinical Signs
• Usually single skin lesion
– Small, firm papule
– Fingers or hands
– Eventually lesion covered by
crust
• Often resolves spontaneously
– Immunosuppressed people at greater risk for
complications
Center for Food Security and Public
Health, Iowa State University, 2012
Who Is At Risk?
• Close contact with sheep/goats
– Herders/Owners
– Sheep-shearers
– Veterinarians
– Butchers
– Abattoir workers
Diagnosis
• Electron microscopy
• Biopsy
• PCR
• Histopathology
• Virus isolation
• Serology, antigen detection
Treatment
• Usually self-limiting
– Supportive care
• Wound dressings
• Local antiseptics
• Finger immobilization
• Antibiotics for secondary infections
– Surgery (large lesions)
– Cryotherapy
Center for Food Security and Public
Health, Iowa State University, 2012
PREVENTION AND CONTROL
Prevention in Humans
• Avoid contact with infected animals,
scabs/crusts, wool, and hides
– Especially if immunosuppressed
• Wear gloves
– When handling
susceptible animals
– When vaccinating
• Wash hands
Center for Food Security and Public
Health, Iowa State University, 2012
