does anyone know what orf is?

Answer 1

Background: Orf is a viral disease that is widespread in sheep and goats. It can be transmitted to humans by contact with an infected animal or contaminated fomites. Reindeer have also caused similar lesions in humans. It is frequently seen in farming communities and meat handlers. Clinically, reddish weeping nodules are seen on the dorsa of the hands and the fingers that heal spontaneously in about 35 days.


Pathophysiology: Orf is primarily a disease involving the skin, though the lymph nodes are occasionally involved.


Frequency:


Internationally: A higher frequency of reports has occurred from Europe and New Zealand compared with North America, but this is of unknown significance.
Mortality/Morbidity: The natural course of the disease is spontaneous recovery in 3-6 weeks.

Immunocompromised patients can have progressive, destructive lesions requiring medical interventions such as antiviral therapy and surgical debridement. However, reports exist of immunosuppressed individuals with large, fungating lesions that have been refractory to treatment.
Mortality has not been reported.
Race: Orf has been reported exclusively in whites.

Sex: No sexual predilection is reported.

Age: No age predilection is described.




CLINICAL Section 3 of 10
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History:

Orf usually appears as a small papule on the dorsum of the index finger 1 week following contact with an infected animal or contaminated fomite.
Low-grade fever may occur and usually subsides within 3-4 days.
Physical: Orf appears as a solitary lesion or as a few lesions on the fingers, the hands, or the forearms, and it has even been reported on the face. The lesion starts as a small, firm, red-to-blue papule that grows to form a hemorrhagic, flat-topped pustule or bulla. The bulla may have a crust in its umbilicated center. The fully developed lesion is typically 2-3 cm in diameter, but it may reach 5 cm. It is often tender and may bleed easily.

Regional adenitis and/or mild lymphangitis may be found.
Mild fever and malaise may be associated.
Large, fungating lesions have been reported in patients who are immunosuppressed and in patients with atopic dermatitis.
The infection goes through 6 clinical stages, each lasting about 1 week.
Stage 1 (maculopapular) - A red elevated lesion
Stage 2 (targetoid) - A bulla with an irislike configuration (nodule with a red center, a white middle ring, and a red periphery)
Stage 3 (acute) - A weeping nodule
Stage 4 (regenerative) - A firm nodule covered by a thin crust through which black dots are seen
Stage 5 (papillomatous) - Small papillomas appearing over the surface
Stage 6 (regressive) - A thick crust covering the resolving elevation
Causes: The disease is caused by infection with the orf virus that belongs to the Parapoxvirus genus, which also includes the milker's nodule virus. Parapoxvirus is a member of the family Poxviridae, which contains double-stranded DNA viruses known to be the largest viruses.

The orf virus is a cylindrical virus measuring 260 X160 nm. Its surface tubules form a long crisscross design that is seen on negatively stained preparations by electron microscopy. This virus resists physical damage and persists through the winter months on hedges, feeding troughs, and barns.
Orf is transmitted by direct contact inoculation. Humans acquire the infection from contact with infected animals, carcasses, or contaminated, nonliving material. It is very common among shepherds, veterinary surgeons, and farmers' wives who bottle-feed young lambs, as well as in butchers and meat porters from handling infected carcasses.
No transmission occurs to cattle, and no human-to-human transmission occurs.