A U.K. veterinarian has possibly linked common face flies to the spread of sarcoids, one of the most commonly encountered equine neoplasias (tumors), and it is conceivable that the risk of spreading sarcoids could be minimized through horse management techniques. The research also further supports that bovine papillomaviruses (BPV) are involved in causing equine sarcoids in horses.

Jeremy Kemp-Symonds, MRCVS, a PhD student at the Animal Health Trust in Newmarket presented study results during the clinical research sessions at the 46th Congress of the British Equine Veterinary Association, held in Edinburgh, Scotland, Sept. 12-15, 2007.

"Despite being very common, there’s a great deal that we don’t understand about equine sarcoid," said Kemp-Symonds. "It appears to have a viral etiology, but an unresolved mode of transmission." He noted that fly vectors are mentioned often in the scientific literature about sarcoids, and he said there are numerous anecdotal reports of sarcoids developing at sites of previous injury and trauma. He also said it is common for horses to get sarcoids in the perigenital region, where flies often sit.

According to Kemp-Symonds, Musca autumnalis face flies feed on lachrymal (tearduct), oral, and nasal discharges, and wound secretions. "M. autumnalis is closely associated with predilection sites for sarcoids, and it’s an important vector of veterinary diseases," he added. The researchers collected and froze more than 500 M. autumnalis flies infesting six sarcoid-affected Thoroughbred or Thoroughbred-cross horses from the Wye Valley area (encompassing the border of England and Wales). They ran a type of DNA assay called a polymerase chain reaction test on the flies and on tissue from sarcoid-infected horses