EFFICACY OF THE ADMINISTRATION OF SERUM AND VACCINE IN THE TREATMENT OF RABIES IN EXPERIMENTALLY-INFECTED SHEEP

The objectives of this study were to examine the humoral immune respon se of sheep to experimental infection with an isolate of rabies virus from a fox, to analyse the efficacy of vaccination as a method of post -infection treatment, and to find a suitable animal model to evaluate new procedures for human vaccination following infection. A total of 4 7 sheep were used. lnitially, 26 sheep received an intramuscular injec tion of a suspension of virus (titre: 10(6.8) 50% lethal dose for mice by the intracerebral route). Half of the sheep were subsequently trea ted using a vaccine on the day of infection and at 3, 7, 14 and 30 day s post-infection. The remaining half comprised the unvaccinated contro ls. This vaccination protected seven of thirteen sheep, while nine of the thirteen controls died. Subsequently, 21 sheep were inoculated und er the same conditions as in the previous trial, The animals were divi ded into three groups of seven animals each. The first group was vacci nated in the same way as described above. Tile second group received a n injection of and-rabies immunoglobulin of human origin (26.3 IU/kg o f body weight), followed by the course of vaccine treatment 24 hours l ater The remaining group acted as unvaccinated controls Of the seven s heep given vaccine alone, four were protected while all seven animals given immunoglobulin and vaccine were protected. Six of the seven untr eated controls died. In this study, no apparently-healthy carriers or rabies virus were created by any of the treatments used, nor was there any shortening of the incubation periods. Additional observations wer e made concerning incubation periods and the course of the disease as well as symptoms, lesions and the presence of rabies virus in various nerve centres and salivary glands of the experimental sheep.