Indirect oral immunization of captive vampires, Desmodus rotundus.

A vaccinia-rabies glycoprotein recombinant virus (V-RG) vaccine was tested in hematophagous bats (Desmodus rotundus) kept in captivity. The vaccine was applied in a neutral vehicle (Vaseline) spread on the back of one or two vector bats, which were then reintroduced into their groups. Our hypothesis was that, as in the case of vampire bat control by vampiricide paste, the administration of V-RG vaccine through paste to one bat could indirectly protect other bats from the same group. Eight groups were tested. The rabies virus strain used to challenge the bats was isolated from a naturally infected hematophagous bat (Desmodus rotundus). The survival proportion after the virus challenge ranged between 42.8 and 71.4%. The results are encouraging because a significant number of bats that did not receive the vaccine survived the challenge. The vaccine was shown to be safe and immunogenic to hematophagous bats. No adverse effects to vaccinia virus were observed.