Ant sting mortality in Australia
Introduction
Ants are widespread Hymenopteran insects of the family Formicidae with approximately 8800 species described worldwide. Australia is richly endowed with 2750 known species and subspecies (Shattuck, 1999). However, despite this diversity there are relatively few species of medical importance and those can be divided into two major groups, distinguished by the extent of development of a venom injection apparatus. The first type has no effective apparatus while the second group has a clearly recognisable sting.
The former type, exemplified by the ‘meat’ ant, Iridomyrmex spp., can cause irritating bites that they spray with secretions from their abdominal glands (Southcott, 1988). The second group, typified by the Myrmecia ants, subfamily Myrmeciinae, are notable for their painful true stings and allergenic venom. Known as ‘jumper’ or ‘bulldog’ ants they are widely distributed in, and virtually endemic to, Australia. Amongst the at least 89 Myrmecia species identified so far, only two are well known; the small (10 mm long), jack jumper (Myrmecia pilosula), which is black with yellow mandibles, and the larger (15–20 mm long), bull ant (Myrmecia pyriformis) that is a duller brown in colour.
Both species are widely found throughout much of south-east Australia, including Tasmania. M. pilosula is also found in the south-west tip of Western Australia and much of South Australia (Sutherland and Tibballs, 2001). Other stinging ants, such as the IFA (Solenopsis spp.) and the primitive genus Rhytidoponera, are also found in Australia (Southcott, 1988). However, to date only four minimally documented ant sting fatalities are recorded in the Australian medical literature. In 1931, Cleland recorded three ant sting related fatalities, two adults and an infant, all from NSW. One fatality, a middle aged woman, was recorded from Tasmania in 1963 (Trinca, 1964, Lee, 1975).
Detailed analysis of fatalities can provide an important source of information on the determinants of severe morbidity for the purposes of injury prevention. Therefore, as part of a study of Hymenopteran fatalities in Australia (Levick et al., 1997, Levick et al., 2000, McGain et al., 2000, McGain et al., 2001), we undertook an analysis of ant sting related fatalities that occurred in Australia over the last two decades. We discuss the cases identified and make prevention and treatment recommendations.
Section snippets
Methods
In the absence of national coronial data for the study period, we proceeded through the national statistical database through to individual state-based coronial systems and, where necessary, individual clinicians. Specifically we searched, with their approval, the Australian Bureau of Statistics (ABS) mortality dataset for ant sting related fatalities that occurred during the period 1 January 1980–31 December 1999. With the consent of the relevant state and territory registrar—generals of
Results
We identified six fatalities that equates to a mean national annual incidence rate of 0.02 deaths per million population per year during the 20-year period. The fatalities were marked temporally skewed such that most (5/6) occurred in the second 10-year period and all of the cases occurred within an 11-year period. All of the deceased were men living in either NSW (1/6) or Tasmania (5/6). The average age of death was 58 years, with the range being from 40 to 80 years. All fatalities occurred
Discussion
This study confirms the lesser importance of ant stings, compared with snakebite, and bee and wasp sting fatalities, in Australia (Harvey et al., 1984, Sutherland, 1992, Sutherland and Leonard, 1995, Levick et al., 2000, McGain et al., 2000, McGain et al., 2001). This national mortality ranking is similar to that recorded in the USA (Barnard, 1973, Langley and Morrow, 1997, Prahlow and Barnard, 1998) with both countries reporting a near-identical fatality rate for ant stings (Langley and
Acknowledgements
This study was supported by grants from the Victorian Department of Human Services and Bayer Healthcare Limited. It could not have proceeded without the assistance of Mr Peter Burke, Ms Muriel Meyer and Mr David Jayne at the Australian Bureau of Statistics, Brisbane, as well as the various state and regional coronial authorities, hospitals and individual clinicians. We also thank Ms Gail Knowland and Dr Brian Baldo, Kolling Institute of Medical Research for provision of post-mortem assay
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Cited by (33)
Pest animals
2017, Animals and Human SocietyCurrent advances in ant venom proteins causing hypersensitivity reactions in the Asia-Pacific region
2016, Molecular ImmunologyCitation Excerpt :Usually anaphylactic reactions in Australia are caused by M. pilosula and M. pyriformis species. Fatalities are rare and reports showed mean national annual incidence of 0.02 deaths per million populations per year in the period 1980–1999 (McGain and Winkel, 2002). Although allergy is common in southeastern Australia, only 4 deaths have been reported from the southern island of Tasmania (population 223,000) between 1980 and 1999 (Brown et al., 2001).
Pilosulins: A review of the structure and mode of action of venom peptides from an Australian ant Myrmecia pilosula
2015, ToxiconCitation Excerpt :Between 2002 and 2005, 60.8% of the 211 hospitalised cases involving ant sting allergy were due to M. pilosula and Myrmecia pyriformis (bulldog ant) (Bradley, 2008). In addition, Australian coronial records between 1980 and 1999 attributed six deaths due to anaphylaxis to the venom of M. pilosula, M. pyriformis, or Myrmecia forficata (inchman ant) (Brown et al., 2001; Klotz et al., 2005; McGain and Winkel, 2002). In comparison to other insect venoms, the venom of M. pilosula appears to be particularly allergenic (Taylor, 1987).
Diversity of peptide toxins from stinging ant venoms
2014, ToxiconCitation Excerpt :In South Eastern Australia around 2.7% of the population are allergic to Myrmecia pilosula venom, with approximately 50% of allergic people experiencing life-threatening reactions (Brown et al., 2003). The toxicity of the venom appears to result from the presence of a variety of histamine-like, haemolytic and eicosanoid-releasing factors, peptides such as pilosulins, and enzymes including phospholipases, hyaluronidase, and phosphatases (Matuszek et al., 1994a, 1992, 1994b; McGain and Winkel, 2002). Using cDNA sequencing, two major protein allergens from Myrmecia pilosula sharing a common leader sequence have been identified (Donovan et al., 1993, 1995, 1994; Street et al., 1996).
Animal Bites and Stings with Anaphylactic Potential
2009, Journal of Emergency MedicineAnaphylaxis fatalities and admissions in Australia
2009, Journal of Allergy and Clinical ImmunologyCitation Excerpt :These differing demographics can assist in the identification of those at the highest risk of fatality from a specific allergy. For both food-induced and non–food-induced anaphylaxis, we identified similar risk factors for death, as previously reported in UK, US, and Australian studies.4,7-10,14-16 Risk factors for food anaphylaxis were age 10 to 35 years, active asthma, peanut allergy, ingestion of food prepared outside of the subject's residence, and delayed administration of adrenaline.