Jaagsiekte sheep retrovirus Jaagsiekte sheep retrovirus Jaagsiekte sheep retrovirus (JSRV) is a betaretrovirus which is the causative agent of a contagious lung cancer in sheep, called ovine pulmonary adenocarcinoma. JSRV is the virus that is the cause of the contagious lung tumors in sheep called ovine pulmonary adenocarcinoma (OPA). The disease has also been called "jaagsiekte", after the Afrikaans words for "chase" ("jaag") and "sickness" ("siekte"), to describe the respiratory distress observed in an animal out of breath from being chased, indicating the breathing difficulty experienced by infected sheep. Transmission of virus is through aerosol spread between sheep. The exogenous infectious form of
Abolitionism (animal rights) forms of animal use, since they believe this undermines the movement to abolish all forms of animal use. The objective is to secure a moral and legal paradigm shift, whereby animals are no longer regarded as things to be owned and used. The American philosopher Tom Regan writes that abolitionists want empty cages, not bigger ones. This is contrasted with animal welfare, which seeks incremental reform, and animal protectionism, which seeks to combine the first principles of abolitionism with an incremental approach, but which is regarded by some abolitionists as another form of welfarism or "New Welfarism". The word relates