Venomous marine life in Queensland: Morbidity study.

In Queensland during the period January 1991 to July 1995 there were 525 hospital admissions resulting from contact with venomous marine animals and plants, excluding sea snakes (ICD-9-CM code E905.6) .' These admissions varied considerably across geographic regions of the state and among population subgroups. The case numbers decrease markedly from north to south, with a maximum in the Peninsula region (as defined by Queensland Health), which extends south from Cape York to Cardwell (latitude 11"-18" south: Figure 1). The same generally applies for age-adjusted rates. Compared with the South Coast, residents in Peninsula region had an age-adjusted risk ratio of 16.6 (95%CI 3.2-86.2). The exception to this gradient was the Mackay region (latitude 20"-22" south). There was no significant difference in the hospital admission rate between Central (latitude 22"-24" south) and Wide Bay region (latitude 24"-26" south), whereas the Sunshine Coast region (latitude 26"-27" south) had significantly lower hospital admission rates than both of the latter regions. All latitudes are rounded to the nearest integer. In all regions there were 3-4 times more males admitted than females, with an overall proportion of 75% male for the state (Figure 2). Furthermore, residents aged 5-29 had greater hospital admission rates, leading to markedly disparate age-specific hospital admission rates, presumably reflecting different patterns of exposure in this age group. The overall trend of increasing rates up the Queensland coast would be influenced, not only by distribution of venomous marine species (eg the Chironex f i c k m ' box-jellyfish has only been found in waters north of latitude 24" south),' but by population numbers exposed through water-based activities. The ICD-9-CM external cause codes do not allow a more definitive breakdown of the causes of these hospital admissions. However, the majority would have been caused by venomous marine animals, principally jellyfish, because the probability of venomous marine plants on the Queensland coast (causing bodily harm requiring hospitalisation) is estimated to be small. Attribution of residential location is based on the address provided by the patient at admission. A potential source of misclassification bias could be the over-assignment of cases to regions, due to patients providing their temporary address. The practice of ensuring that the usual address is registered varies between hospitals included in this study, but the majority request the permanent address. Furthermore, all admissions may not have been incident cases, although a separate code should be used for all late effects of accidental injury (E929). In -addition to its inherent usefulness, these data provide information to support health promotion regarding prospective target audiences for marine safety programs.