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
Animal studies of Natural History showed family groupings that conformed to the traditional human nuclear family, which misrepresented the animals' observed behavior in the wild. Critical approaches in animal studies have also considered representations of non-human animals in popular culture, including species diversity in animated films. By highlighting these issues, animal studies strives to re-examine traditional ethical, political, and epistemological categories in the context of a renewed attention to and respect for animal life. The assumption that focusing on animals might clarify human knowledge is neatly expressed in Claude Lévi-Strauss's famous dictum that animals are "good to think." Animal studies Animal studies