A survey of aldicarb poisoning in dogs and cats in Gauteng and evaluation of the efficacy of hydroxypropyl-β-cyclodextrin as a treatment in aldicarb poisoning

Abstract

Worldwide, pesticides are applied to protect crops against insects, fungi and other parasites. Without these chemicals it would not be possible to produce sufficient food to satisfy the demand of an ever-increasing world population. Unfortunately, many cases of accidental and intentional poisoning of humans and animals occur and the objectives of this study were to obtain statistics of aldicarb poisoning in companion animals in Gauteng Province and to evaluate hydroxypropyl-<font face="symbol">b</font>-cyclodextrin as a potential treatment. Cyclodextrins are ring-shaped oligosaccharides with a hydrophilic exterior and a hydrophobic interior. The interior cavity is capable of complexing fat-soluble molecules small enough to fit inside. Aldicarb is moderately lipid-soluble, non-ionized and of low molecular weight and thus fits all criteria for complexation with cyclodextrin. Questionnaires were posted to all private practitioners in Gauteng. The survey was designed to determine the percentage of aldicarb cases seen, clinical signs observed, treatment regimen, proposals for preventative actions and more effective treatments. Other questions included duration of treatment, survival rate, cost to client, post-mortem findings and reasons for poisonings. Thirty-four percent of respondants indicated the total number of all clinical cases presented at their practices during 2003. The percentage of suspected aldicarb cases as a proportion of all cases ranged from 0.05 - 2.6 % for dogs and 0.09 - 3.33 % for cats. Only 26.5 % of practitioners sometimes submitted samples for laboratory confirmation of aldicarb poisoning. Salivation and tremors were the most common clinical signs observed by private practitioners and the majority of suspected poisoning cases were treated with atropine, intravenous fluid and electrolyte therapy and the oral administration of activated charcoal. Thirty-three respondents thought that there was an increase in the number of aldicarb cases, but 35 felt there was no increase during 2003. Fifteen respondents were reluctant to venture an opinion. Most veterinarians indicated that criminal intent was the main reason why animals were poisoned and 95 % of respondents reported that it occurred throughout the year, but an increased incidence was observed during holiday periods.Survival times in the majority of rats dosed with aldicarb and receiving intravenous cyclodextrin were longer, compared to the control rats only dosed with aldicarb per os. Rats receiving cyclodextrin immediately before aldicarb, survived longer when compared to rats, which received aldicarb prior to cyclodextrin.