It may appear similar to cowpox and pseudocowpox. While orf is usually a benign self-limiting illness which resolves in 3-6 weeks, in the immunocompromised it can be very progressive and even life-threatening. One percent topical cidofovir has been successfully used in a few patients with progressive disease. Serious damage may be inflicted on the eye if it is infected by orf, even among healthy individuals. The virus can survive in the soil for at least six months. Other animals
Orf is primarily a disease of sheep and goats although it has been reported as a natural disease in humans, steenbok and alpacas, chamois and tahrs, reindeer, musk oxen, dogs, cats, mountain goats, bighorn sheep, dall sheep, and red squirrels. Sheep and goats
It has been recorded since the late 19th century and has been reported from most sheep-or goat-raising areas, including those in Europe, the Middle East, the United States, Africa, Asia, South America, Canada, New Zealand and Australia. Orf is spread by fomites and direct contact. In some environments, infection is injected by scratches from thistles of both growing and felled plants. Symptoms include papules and pustules on the lips and muzzle, and less commonly in the mouth of young lambs and on the eyelids, feet, and teats of ewes. The lesions progress to thick crusts which may bleed. Orf in the mouths of lambs may prevent suckling and cause weight loss, and can infect the udder of the mother ewe, thus potentially leading to mastitis. Sheep are prone to reinfection.
Obstruction  may refer to:

Places
Obstruction Island, in Washington state
Obstruction Islands, east of New Guinea

Medicine
Obstructive jaundice
Obstructive sleep apnea
Airway obstruction, a respiratory problem
Recurrent airway obstruction
Bowel obstruction, a blockage of the intestines. Gastric outlet obstruction
Distal intestinal obstruction syndrome
Congenital lacrimal duct obstruction
Bladder outlet obstruction

Politics and law
Obstruction of justice, the crime of interfering with law enforcement
Obstructionism, the practice of deliberately delaying or preventing a process or change, especially in politics
Emergency Workers (Obstruction) Act 2006

Science and mathematics
Obstruction set in forbidden graph characterizations, in the study of graph minors in graph theory
Obstruction theory, in mathematics
Propagation path obstruction
Single Vegetative Obstruction Model

Sports
Obstruction (baseball), when a fielder illegally hinders a baserunner
Obstructing the field

See also
The Five Obstructions, a 2003 film
USS Obstructor, an American minelayer ship used in World War II