Orf (disease)

Orf
Other namesContagious pustular dermatitis, contagious ecthyma, infectious labial dermatitis, ecthyma contagiosum, thistle disease, scabby mouth[1]
A thumb with two denuded orf lesions, following a bite by a sheep
SpecialtyInfectious diseases, veterinary medicine Edit this on Wikidata

Orf is a farmyard pox, a type of zoonosis.[2] It causes small pustules in the skin of primarily sheep and goats, but can also occur on the hands of humans.[3] A pale halo forms around a red centre.[4] It may persist for several weeks before crusting and then either resolves or leaves a hard lump.[4] There is usually only one lesion, but there may be many, and they are not painful.[4] Sometimes there are swollen lymph glands.[4]

It is caused by a Parapoxvirus.[5] It can occur in humans who handle infected animals or contaminated objects.[2] One third of cases may develop erythema multiforme.[4] Once resolved, a person can still be infected again.[4]

Generally, treatment options are limited.[4] Injecting the lesion with cidofovir or applying imiquimod has been tried.[4] It is sometimes necessary to cut them out.[4] The vaccine used in sheep to prevent orf is live and has been known to cause disease in humans.[4]

The disease is endemic in livestock herds worldwide.[2] A recent outbreak emerged in southwest Ethiopia between October 2019 and May 2020.[2]

  1. ^ Winter, Agnes; Charmley, Judith (1999). The Sheep Keeper's Veterinary Handbook. Crowood Press Ltd (Marlborough, UK). ISBN 978-1-86126-235-6.
  2. ^ a b c d Kassa, T (2021). "A Review on Human Orf: A Neglected Viral Zoonosis". Research and Reports in Tropical Medicine. 12: 153–172. doi:10.2147/RRTM.S306446. PMC 8275206. PMID 34267574.
  3. ^ Barlow, Gavin; Irving, William L.; Moss, Peter J. (2020). "20. Infectious disease". In Feather, Adam; Randall, David; Waterhouse, Mona (eds.). Kumar and Clark's Clinical Medicine (10th ed.). Elsevier. p. 517. ISBN 978-0-7020-7870-5.
  4. ^ a b c d e f g h i j Petersen, Brett W.; Damon, Inger K. (2020). "348. Smallpox, monkeypox and other poxvirus infections". In Goldman, Lee; Schafer, Andrew I. (eds.). Goldman-Cecil Medicine. Vol. 2 (26th ed.). Philadelphia: Elsevier. pp. 2184–2185. ISBN 978-0-323-53266-2.
  5. ^ James, William D.; Elston, Dirk; Treat, James R.; Rosenbach, Misha A.; Neuhaus, Isaac (2020). "19. Viral diseases". Andrews' Diseases of the Skin: Clinical Dermatology (13th ed.). Edinburgh: Elsevier. p. 389. ISBN 978-0-323-54753-6.