Reactions to tick antitoxin serum and the role of atropine in treatment of dogs and cats with tick paralysis caused by Ixodes holocyclus: a pilot survey.
OBJECTIVE
To determine the incidence and nature of adverse reactions of dogs and cats to tick antitoxin serum and to re-evaluate the role of atropine in the treatment of tick paralysis.


METHODS
A retrospective questionnaire of veterinarians.


METHODS
Questionnaires were posted to 320 veterinarians in tick-endemic regions of Australia. Questions referred to dogs and cats treated for tick paralysis over a period of three years: the number treated, treatment protocols and adverse systemic reactions to tick antitoxin serum. Ninety completed questionnaires were returned and responses analysed.


RESULTS
Veterinarians reported that approximately 3% of dogs exhibited adverse reactions immediately following treatment with tick antitoxin serum. Eighteen percent of these reactions were described as anaphylaxis, with the remaining 82% attributed to the Bezold-Jarisch reflex. Six percent of cats treated with tick antitoxin serum reacted adversely and the majority of reactions (63%) were ascribed to the Bezold-Jarisch reflex. Atropine was used routinely by 10% of responding veterinarians in the treatment of dogs and cats with tick paralysis. A similar number of veterinarians used atropine only in selected cases. Most veterinarians (76%) reported that they never used atropine in the treatment of tick paralysis in either dogs or cats. Within the survey population, premedication with atropine reduced the number of Bezold-Jarisch reactions following tick antitoxin administration approximately five-fold in dogs and four-fold in cats.


CONCLUSIONS
Data from this pilot survey indicate that more cats than dogs have adverse systemic reactions to tick antitoxin serum and that the majority of these reactions in both dogs and cats could be related to the Bezold-Jarisch reflex. The number of reactions to tick antitoxin serum in dogs and cats could be significantly reduced by the routine use of atropine prior to administration of tick antitoxin serum.
Atwell
R B
RB
School of Veterinary Science, The University of Queensland.
Campbell
F E
FE
D000818:Animals; D000992:Antitoxins / Q000009:adverse effects*; D001285:Atropine / Q000008:administration & dosage*; D002371:Cat Diseases / Q000188:drug therapy* / Q000628:therapy; D002415:Cats; D004283:Dog Diseases / Q000188:drug therapy* / Q000628:therapy; D004285:Dogs; D004334:Drug Administration Schedule; D006801:Humans; D018884:Ixodes / Q000276:immunology; D018727:Muscarinic Antagonists / Q000008:administration & dosage*; D009517:New South Wales; D010865:Pilot Projects; D011793:Queensland; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D013985:Tick Paralysis / Q000188:drug therapy / Q000628:therapy / Q000662:veterinary*; D014730:Veterinary Medicine
D000992:Antitoxins; D018727:Muscarinic Antagonists; D001285:Atropine