Transmission of Vesicular Stomatitis Virus from Infected to Noninfected Black Flies Co-Feeding on Nonviremic Deer Mice

Abstract

Vesicular stomatitis is an economically important arboviral disease of livestock. Viremia is absent in infected mammalian hosts, and the mechanism by which insects become infected with the causative agents, vesicular stomatitis viruses, remains unknown. Because infected and noninfected insects potentially feed on the same host in nature, infected and noninfected black flies were allowed to feed on the same host. Viremia was not detected in the host after infection by a black fly bite, but because noninfected black flies acquired the virus while co-feeding on the same host with infected black flies, it is concluded that a viremic host is not necessary for an insect to be infected with the virus. Thus co-feeding is a mechanism of infection for an insect-transmitted virus.

Experimental Infection of Didelphis Marsupialis With Vesicular Stomatitis New Jersey Virus

“…The experimental infection of two pronghorn antelope (Antilocapra americana) with VSNJV via IE/ SE (Thorne et al, 1983, cited by Webb et al, 1987 produced similar results to the ones described in deer. We were also able to detect virus excretion through different routes, but never in blood samples; therefore, we propose that these sites could be a possible source of infection for mechanical vectors, a possibility that has been proposed by others in earlier investigations (Ferris et al, 1955;Mason, 1978;Mead et al, 2000).…”

Vesicular stomatitis New Jersey virus (VSNJV) infects keratinocytes and is restricted to lesion sites and local lymph nodes in the bovine, a natural host

“…However, it is possible that livestock are dead-end hosts and that other mammalian hosts might be responsible for maintaining the natural virus-insect cycle [3,4]. Alternatively, recent studies have shown horizontal insectto-insect transmission of VSV while cofeeding in non-viremic mammalian hosts theoretically making viremia unnecessary for insect to insect transmission [13].…”

Olfaction in vector-host interactions

“…VSV does not establish high viremias in its vertebrate hosts (e.g. cattle) making its transmission by black flies (and other blood feeders) something of a mystery that appears to have been solved by Mead et al (2000) who showed that VSV transmission can occur between black flies as they feed on the same host.…”