Vesicular stomatitis virus (VSV) is the prototype of the family Rhabdoviridae and infects a broad range of animals, including cattle, horses, and swine (12). VSV infection of livestock is associated with significant disease, including vesicular lesions around the mouth, hoofs, and teats, and with loss of beef and milk production (3,38). Although rarely fatal, VSV infection mimics early symptoms caused by a notorious veterinary pathogen of horses and cattle, foot-and-mouth disease virus (38). VSV infection of livestock occurs periodically within the United States, is associated with one of two serotypes of VSV (Indiana, VSVI, or New Jersey, VSVNJ), and is usually not widespread. However, major VSV epizootics occur approximately every 10 to 15 years within the United States, with the last two having occurred in 1982–1983 and 1966 (29, 39). In 1997, 183 confirmed cases of VSVI were reported in four states (36). Arthropod vectors, such as phlebomite sandflies (8, 27) andAedes mosquitoes (34), have been found to harbor VSVI in nature and likely participate in the spread of the virus from animal to animal and possibly from animals to humans.
Naturally occurring human infections with VSV are rare. However several cases of VSV infection have been reported for individuals directly exposed to infected livestock (6) and for researchers directly exposed within laboratory environments (12, 13,25). Most VSV infections are thought to be asymptomatic in humans; however, febrile illness, including chills, myalgia, and nausea, has been reported in infected individuals (5, 10, 12,13). A single case of encephalitis associated with VSVI infection in a 3-year-old boy was reported in 1988 (28).