Black flies can transmit vesicular stomatitis virus

Black flies are always bothersome around livestock animals. This year their presence is even more troublesome because of their transmission of vesicular stomatitis virus (VSV). “There is compelling evidence that insect vectors, primarily black flies, introduce VSV into populations of domestic animals,” said Jason Turner, New Mexico State University (NMSU) Extension equine specialist. “Last year we had a pretty bad outbreak. Because of the mild winter, and other conditions, black flies are already bothersome and reports of the virus are already being received.” Outbreaks typically occur in the southwest U.S. beginning in late spring or early summer and normally continue through late fall, progressing northward along riverways and valleys. “It primarily affects equids, cattle and swine, but it can also occur in sheep, goats, llamas, alpacas and a variety of wild vertebrates,” Turner said. “As a zoonotic disease, VSV can infect humans and cause flu-like symptoms, so it is important that people handling infected horses practice proper biosecurity to protect themselves as well as other animals.” The incubation period, or time from exposure to presence of clinical symptoms, usually ranges from two to eight days. “Drooling and excess salivation are typically the first symptoms noticed,” Turner said. “Upon closer examination, there may be blanched areas and the characteristic vesicles or blisters in and around the mouth. These lesions are quite painful and can cause loss of appetite and/or refusal to drink water.” Minimizing the risk of exposure for horses is the best preventative measure. The following suggestions can help reduce the incidence of vesicular stomatitis...MORE