Evaluation on Outcome of Animals Exposed to Rabies, Kansas 2012 - 2015

BACKGROUND:  Rabies is a highly fatal zoonotic disease of mammals.  Wildlife is a reservoir for the virus and vaccination of domestic animals is imperative to prevent spillover and human infections.  Kansas regulations require domesticated animals exposed to rabies, and not currently vaccinated, to be euthanized or quarantined for six months.  Follow-up on quarantined animals presents a significant burden on public health resources.  A study by Kansas State University Rabies Laboratory indicated dogs and cats with an out-of-date rabies vaccination have a similar anamnestic response to a rabies booster when compared to those with a current vaccination.  We evaluated the outcome of animals exposed to rabies to determine the appropriate post-exposure management practices. 

METHODS:  Animal rabies cases reported to Kansas Department of Health and Environment from January 1, 2012 – December 11, 2015 were evaluated to identify exposed animal contacts.  Animal contacts were assessed to determine their vaccination status, disposition, and outcome.  Vaccination status was categorized as current, out-of-date, unvaccinated, or unknown.  Animal contacts with a current rabies vaccination were excluded from analysis.  Disposition was classified as six-month quarantine, euthanasia, lost to follow-up, or death due to unrelated causes. 

RESULTS:  There were 114 rabid animal cases with at least one animal contact.  Two-hundred nineteen animal contacts were potentially exposed to rabies; 68 (31%) were current on rabies vaccination, 32 (15%) were out-of-date, 108 (49%) were unvaccinated, and 11 (5%) had unknown vaccination status.  Of the 32 out-of-date contacts, 16 (50%) were euthanized and 16 (50%) were quarantined (14 survived, 1 exhibited neurological signs and tested negative for rabies, and 1 was lost to follow-up).  For the 108 unvaccinated contacts, 81 (75%) were euthanized, 1 (1%) developed neurological signs and tested positive for rabies, and 26 (24%) were quarantined (23 survived, 2 died from unrelated causes, and 1 was lost to follow-up).  For the 11 animal contacts with unknown vaccination, 9 (82%) were euthanized and 2 (18%) were quarantined (1 exhibited neurological signs and tested negative for rabies and 1 was lost to follow-up).

CONCLUSIONS: No animal contacts with out-of-date rabies vaccination developed rabies during a six-month quarantine after exposure to a known rabid animal.  One unvaccinated animal contact developed rabies; however, a majority of unvaccinated animals were euthanized immediately.  Policy changes could be considered to manage out-of-date dog and cat contacts similarly to those that are current on rabies vaccination.  This would reduce the number of animals euthanized and burden on scarce public health resources.