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
Alternatives to animal testing OECD program. The testing of chemicals is labor-intensive and expensive. Often the same chemical is tested in several countries simultaneously, which means that redundant animal tests are performed. To relieve some of this burden, the OECD Council adopted a decision in 1981, stating that data generated in a member country, in accordance with OECD Test Guidelines and Principles of Good Laboratory Practice (GLP), shall be accepted in other member countries for assessment purposes and other uses relating to the protection of human health and the environment. This principle is referred to using the acronym MAD, for the Mutual Acceptance of