Aggressive research efforts to discover how the sarcoid-causing bovine papillomaviruses (BPV) are spread either within or between horses have resulted in the identification of BPV genetic material (DNA) in circulating blood cells. This novel finding suggests a possible mechanism by which horses prone to developing sarcoids become latently (invisibly) infected and potentially contribute to the spread of the virus.

Sarcoids are a common form of skin tumor in horses. While non-malignant, these growths can be problematic because they can spread to virtually any location on the body and can compromise the use and welfare of the horse. To date, there is no known cure and the mode of BPV transmission remains undetermined.

Until now, BPV DNA has not been detected in horses circulating blood cells (peripheral blood mononuclear cells–a particular kind of white blood cell). Because DNA from other type of pappillomaviruses has been identified in blood, the study authors re-visited this issue and chose to look for very small amounts of DNA.

The authors developed a highly sensitive polymerase chain reaction (PCR) test capable of detecting very small amounts of BPV DNA in the blood from sarcoid-infected horses. Blood from 66 horses was subsequently tested using this new PCR test