Sheep Virus Linked to Lung Cancer?
My husband lived and worked on a farm in South Africa with sheep for many years. He has just been diagnosed with Stage IV non-small cell lung cancer. I have been searching on the web and found a website about a disease that sheep in South Africa get called "jaagsiekte". It states that there might be a link to that sheep disease and human lung cancer. Do you think there is any truth in that?
Anil Vachani, MD, Pulmonologist at Penn Medicine, responds:
The Jaagsiekte Sheep Retrovirus was first described in South Africa in 1915, but it is found on all continents. It is spread from sheep to sheep through close contact via particles in the air. Research has proven that the virus leads to the development of adenocarcinoma of the lung in sheep. The cancer in sheep does resemble a particular type of human lung cancer formerly termed bronchioloalveolar cancer (BAC) [now sub classified into multiple subtypes, ranging from pre-cancerous tumors to more highly aggressive adenocarcinomas], a generally slow-growing tumor that rarely spreads beyond the lung. This type of lung cancer is less likely to be linked to smoking, is seen more often in women and younger patients, and it generally has a better prognosis than other human lung cancers. The similarities between the sheep tumor and BAC have led to research looking for viral causes of BAC, including studies on Jaagsiekte virus. However, to date, there has been no conclusive evidence of a link between Jaagsiekte virus and human lung cancer. The most common causes of human lung cancer (small cell and non small cell) are smoking, exposure to radon, and other environmental exposures.
Reference: Leroux, C. et al. (2007) Jaagsiekte Sheep Retrovirus: from virus to lung cancer in sheep. Veterinary Research 38: 211-228.