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 Animal studies Animal studies is a recently recognized field in which animals are studied in a variety of cross-disciplinary ways. Scholars who engage in animal studies may be formally trained in a number of diverse fields, including geography, art history, anthropology, biology, film studies, geography, history, psychology, literary studies, museology, philosophy, communication, and sociology. They may engage with questions about literal animals, or about notions of "animality" or "brutality," employing various theoretical perspectives, including feminism, Marxist theory, and queer theory. Using these perspectives, those who engage in animal studies seek to understand both human-animal relations now and in the past,