Comparative study of antibody titers produced against two BHK rabies vaccines in field trial experimental condition in dogs by RFFIT

Rabies is acutely fatal encephalitis caused by a neurotropic virus. This virus belongs to the family ofRhabdoviridae and genus of Lyssavirus. The virus is almost always transmitted to human through infectedmammalian saliva. Rabies is inoculated to a wound by an infected animal bite. Since infection is establishedin the CNS, the outcome is almost always fatal. According to the outstanding role of vaccination againstrabies in animals, as well as post-exposure treatment regimen in human, production of cell-cultured rabiesvaccine is the most common interest of researchers. Two BHK-rabies vaccines, one made in the PasteurInstitute of Iran and two in Schering-Plough Animal Health of Madrid, Spain have been tested on 12 dogsdivided into two groups. Sera were taken monthly over 18 months. To evaluate the titer of the rabiesneutralizing antibody, these sera were analyzed by the rapid fluorescence focus inhibition test (RFFIT) in the end of each month. Both study groups showed a sufficient immunogenic response without any significant difference at least one year after first vaccination. With respect to the effective immunization of rabies vaccines, their annual injections would be sufficient. According to the results, at the end of the study (18th month) serum titer in only one dog (No. 7) was less than protective level. Two animals in group one (No. 2 and No. 5) also had serum titers less than protective level. Mean of post vaccination antibody titer were not different in either groups (P=0.35).