Contagious ecthyma B08.0

Notifiable, harmless, local infectious disease caused by contact infection with parapoxviruses (Orfvirus affecting sheep and goats) from the Poxviridae family, zooanthroponosis, with formation of inflammatory nodules at the infection site.

Parapoxvirus (3 species):

• P. bovis 1 (in cattle, pathogen causing stomatitis papulosa)
• P. bovis 2 (in cattle: pathogen causing udder pox; in humans: milking knots)
• P. ovis, formerly known as Orf virus (in sheep, goats and chamois, pathogen of Ecthyma contagiosum).

Local infection through direct contact with the diseased animals.

The Orf virus is distributed worldwide. The occurrence of Orf infection in humans is rare. It is usually linked to specific occupational groups (farmers, sheep breeders, veterinarians). Incidental infections also occur in contact with infected animals (viral lesions on teats and mouths of calves/cows/sheep). An expansion of infected host animals is observed in recent years (cats,reindeer, camels). In rare cases, human-to-human transmission has occurred (Caravaglio JV et al. 2017).

Incubation period: 3-10 days. After that time skin symptoms appear:

• 1st week (maculopapular stage): Single or multiple, rough, erect, 0.5-1.5 cm large, blue-reddish papules or nodules. Regional lymphangitis and lymphadenitis possible.
• 2nd week (cockade stage): Central redness, surrounding white ring, peripheral, inflammatory reddened courtyard.
• Week 3 (serous exudation): Weeping surface.
• Week 4: Dry papules covered with yellow-black crust.
• Week 5: Papillomatous transformation of the surface.
• From 6th week: regression of the papules, rejection of the crust. Always healing without scarring.
• Rarely is an Orf-induced erythema exsudativum multiforme

Virus antigen detection from efflorescence material, antibody titer determination in serum (ELISA), recall antigen testing with parapoxvirus bovis 2-antigen, electron-optical virus detection ( negative staining).

Milking knots: Analogous clinical symptomatology. Differentiation by anamnesis. Which animal contact was present?

Anthrax of the skin: very rare; rapid formation of an inflammatory nodule or pustule; rapid spread, haemorrhagic bladder; early onset of tiredness, malaise, headache with varying degrees of fever.

Granuloma teleangiectaticum: usually only solitary; histology is diagnostic

Chronic papillomatous pyoderma: purulent, painful, pathogen detection

Sporotrichosis: lymphogenically transmitted infection, multiple, less symptomatic, bluish-red nodes arranged in chains along the lymphatic pathways.

Bacterial superinfections. Rarely is the Orf-induced erythema exsudativum multiforme.

The clinical appearance of Ecthma contagiosum (Orf) is identical to that of the milking knot (transmitted by cows), so a distinction is not necessary.

Anamneses/findings: A 43 year old Turkish patient returned to Germany after a 4 week holiday in her Turkish home village. 2 weeks later she developed purulent nodules with an inflammatory yard on the right palm and the index finger.

Questioning revealed that she had taken part in a domestic slaughter of a sheep 14 days earlier. She had suffered slight cuts in these areas. A few days later his blisters appeared at the cuts. She also noticed a slight fever and painful lymphadenitis in her armpit.

Laboratory: BSG 30/50; CRP: 22,4mg/l (norm<5); low neutrophil leucocytosis (11.500/ml); detection of AK against parapoxviruses;

therapy: antiseptic local therapy; furthermore ciprofloxacin for 7 days because of a bacterial overlay.

1. Bodnar MG et al (2001) Facial orf. J Am Acad Dermatol 40: 815-817
2. Caravaglio JV et al(2017) Orf Virus Infection in Humans: A Review With a Focus on Advances in Diagnosis and Treatment.J Drugs Dermatol16:684-689.
3. Degraeve C et al (1999) Recurrent contagious ecthyma (Orf) in an immunocompromised host successfully treated with cryotherapy. Dermatology 198: 162-163
4. Günes AT et al (1982) Ecthyma contagiosum epidemics in Turkey. Dermatologist 33: 384-387
5. Hartmann AA, Büttner MB, Stanka F, Elsner P (1985) Sero- and immunodiagnostics in human parapox virus infection. dermatologist 36: 663-669
6. Hofmann B et al (1995) Ecthyma contagiosum (Orf). Z Hautkr 70: 68-69
7. Joseph RH et al (2015) Erythema multiforme after orf virus infection: a report of two cases and literature review. Epidemiol Infect 143:385-390
8. Kuhl JT et al (2003) A case of human orf contracted from a deer. Cutis 71: 288-290
9. Müller C (2016) Test your expertise. Act Dermatol 42: 221-223
10. Nagington J et al (1965) Milker's nodule virus infections in Dorset and their similarity to orf. Nature 208: 505-507
11. Rajkomar V et al (2015) A case of human to human transmission of orf between mother and child. Clin Exp Dermatol 41:60-63
12. Rieger H et al (2003) Ecthyma contagiosum (Orf) as an uncommon differential diagnosis of infections of the hand. Trauma surgeon 106: 204-206
13. Revenga F et al (2001) Facial orf. J Eur Acad Dermatol Venereol 15: 80-81
14. Thurman RJ et al (2015) Images in clinical medicine. Contagious ecthyma. N Engl J Med 372:e12
15. Torfason EG, Gunadottir S (2002) Polymerase chain reaction for laboratory diagnosis of orf virus infections. J Clin Virol 24: 79-84