Jaagsiekte

Jaagsiekte is a chronic and contagious disease of the lungs in sheep and goats first described in 1865. Its name derives from Afrikaans and means "chasing sickness" such that animals afflicted with the disease are in respiratory distress as if they are out of breath from being chased. It is also referred to as ovine pulmonary adenocarcinoma (OPA). During end-stage disease, animals exude a foamy white fluid from the nose which is thought to be the mode of transmission between animals. Dissected lungs from afflicted sheep are interspersed with multifocal tumors. Some of these are small discrete nodules and others will involve the entire half of a lung lobule. The disease is caused by a retrovirus called the jaagsiekte sheep retrovirus (JSRV) that acutely transforms the lung epithelia into cancerous cells. Specifically, type-2 pneumocytes and club cells of the lung are the likely target for JSRV transformation. The tumors formed there exhibit the overactive secretory functions which are a hallmark of OPA.