Ovine pulmonary adenocarcinoma be predisposed to OPA. Most affected sheep show signs at 2 to 4 years of age. OPA is not a notifiable disease, and therefore it is difficult to assess its prevalence. OPA was first described in the UK in 1888, and described in detail in South Africa in 1891. The disease was initially known as "jaagsiekte" , a word derived from Afrikaans, meaning "chasing sickness," so called because animals are in respiratory distress as if they are out of breath from being chased. It has also been known as sheep pulmonary adenomatosis and ovine pulmonary carcinoma. OPA has been used
Animal cracker popular, the Austin variety has similar nutritional content and animal shapes. The Austin product is labeled under the name of the Kellogg Company, which acquired Keebler in 2001. Stauffer Biscuit Company of York, Pennsylvania, also has a line of animal crackers, which are now distributed by several major discount retailers. Their use of the spices nutmeg and mace give the basic animal cracker a slightly different character from the Nabisco crackers. The Borden corporation also produced a brand of animal crackers, until the late 1970s. They came in a red box, which featured the famous Elsie the Cow logo. Market