IMMUNE-RESPONSE TO RABIES VACCINE IN ALASKAN DOGS - FAILURE TO ACHIEVE A CONSISTENTLY PROTECTIVE ANTIBODY-RESPONSE

Previous studies in Thailand and Tunisia have shown that one injection of dog pre-exposure rabies vaccine does not produce a lasting antibod y titre in a significant group of animals. We therefore duplicated the Thai study in a small North American community using healthy, owned d ogs. A tissue culture vaccine of known high antigenicity was given int ramuscularly as one primary injection and antibody titres were determi ned by the rapid fluorescent focus inhibition test on days 14, 30, 60, 180 and 360. Titres were less than 0.5 i.u./mL in 27% of dogs bled at 2 months, 24% at 6 months, and in 33% one year after the primary vacc ination, In rabies endemic regions, it may be hazardous to rely on the previous vaccine history of a biting dog when making post-exposure ma nagement decisions. A retrospective study of antibody levels in previo usly vaccinated dogs in North America also indicated that a single inj ection of vaccine often failed to result in adequate titres.