Amitraz poisoning in South Africa: A two year survey (2008–2009)

Abstract

Introduction. Analysis of the annual pesticide poisoning statistics of the Tygerberg Poison Information Centre (TPIC) for the period 2005–2007 showed an increase in the number of amitraz poisonings. This prompted a 2-year survey (2008–2009) to establish the extent of amitraz poisoning in South Africa. Amitraz is a pesticide used as a tick dip. It acts as an α2-adrenoceptor agonist and the principal clinical effects of amitraz poisoning are related to its stimulation of these receptors; Methods. Data from amitraz poisoning cases in humans were evaluated for 2 years and analyzed for: demographic data, type of exposure, type of formulation, and clinical details. Serious cases were followed up; Results. 4.6% of the pesticide poisoning cases were amitraz-related which comprised 0.8% of all TPIC poisoning consultations. Ingestion of amitraz formulations accounted for the majority of the cases (94%). Forty-one percent of cases were children (n = 28) and all were accidental exposures. Of the adult cases (59%), 88% were intentional ingestions. The majority of the cases were from the predominantly rural province of KwaZulu Natal (44.9%). CNS depression was the most common clinical sign (76.8%) followed by bradycardia 34.8%, respiratory depression 27.5%, miosis 27.5%, and hypotension 23.1%. Mechanical ventilation was required in 15.9% of cases. Other commonly reported clinical signs were hypothermia 15.9%, mydriasis 10.1%, and hyperglycaemia 7.2%. Supportive and symptomatic care was shown to be adequate treatment. Amitraz poisoning was misdiagnosed as cholinesterase inhibitor poisoning in 17.4% of cases; Conclusion. This is the first report of amitraz poisoning in humans in Africa. The data suggest a different demographic pattern in South Africa to that currently reported in the literature. The study identified a very high incidence of intentional poisoning in adults. The misuse of amitraz for deliberate self-harm emphasizes the necessity for continued toxicovigilance.