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
Alternatives to animal testing test dummies, complete with internal sensors and video, have replaced live animal trauma testing for automobile crash testing. The first of these was "Sierra Sam" built in 1949 by Alderson Research Labs (ARL) Sierra Engineering. These dummies continue to be refined. Prior to this, live pigs were used as test subjects for crash testing. Computer models have been constructed to model human metabolism, to study plaque build-up and cardiovascular risk, and to evaluate toxicity of drugs, tasks for which animals are also used. In 2007, US researchers using the world's fastest computer at the time, BlueGene L, modeled half a