Ovine pulmonary adenocarcinoma Ovine pulmonary adenocarcinoma Ovine pulmonary adenocarcinoma (OPA), also known as ovine pulmonary adenomatosis, or jaagsiekte, is a chronic and contagious disease of the lungs of sheep and goats. OPA is caused by a retrovirus called jaagsiekte sheep retrovirus (JSRV). The disease has a long incubation period, and therefore signs usually occur in adult animals (over 2 years of age). Clinical signs resemble a non-specific progressive pneumonia, including poor body condition and, particularly after exercise, respiratory difficulty. Unless a concurrent lung infection is present, affected sheep continue to eat. The only sign specific to OPA is a watery nasal discharge, consisting
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