Severity and management
The severity of a hospitalisation may be indicated by the urgency of admission, average length of stay, time in intensive care units (ICU) or on continuous ventilatory support (CVS) and the mode of separation from hospital, including death in hospital. Table 9 describes selected severity metrics by type of animal in 2021-22.
- Over 85% of these injury cases were admitted as emergencies, rising to 97% for venomous animal related injuries. This is expected as bites by venomous animals (especially snakes) are considered potential medical emergencies requiring high priority assessment even in people who appear well (Isbister, Brown et al. 2013).
- 60-67% of hospitalisations related to contact with animals were overnight stays. In hospitalisations due to venomous animals the reverse was true with just under half of cases being overnight stays (if asymptomatic after 12 hours, cases may be discharged (Isbister, Brown et al. 2013)). The average length of stay overall was 2 days, with a shorter average of 1.5 days for injuries caused by venomous animals (Table 10). Injuries caused by contact with animals therefore spent less time overall (and by extension used less hospital resources) than most other external causes of injury, with the average length of stay across all injury hospitalisations being 4.7 days (Injury in Australia, Data table A13).
- About 7% of cases overall were transferred to a second acute-care hospital (for venomous animals this was lower at 4% of cases). Regardless of venomousness, 2% of cases left hospital against medical advice or discharged themselves.
- 152 cases, about 1%,regardless of venomousness, spent time in ICU and 44 received continuous ventilatory support (CVS); for injuries overall about 2% spent time in ICU (Injury in Australia, Data table A14).
- Overall, 6 of the 23,379 cases hospitalised due to injuries caused by contact with animals during 2021-22 died in hospital, underlining the rarity of fatalities from injuries caused by animals as compared to other causes of injury (Injury in Australia, Data table A15).
This report does not describe deaths, however research indicates relatively high proportions of fatalities related to allergies caused by insect bites and stings as compared to snake bites. This may indicate complacency about insect bites compared to snakes, with people underestimating the severity of anaphylactic reactions that may result (Welton, Williams et al. 2017).
Type of animal | Emergency admissions | Same day hospitalisation | Transferred to another acute hospital | Left/discharged against medical advice | Time in ICU | Average length of stay |
|---|---|---|---|---|---|---|
Venomous animals# | 97% | 54% | 4% | 2% | 1.4% | 1.5 days |
Common pets | 84% | 33% | 7% | 2% | 0.2% | 2.1 days |
Livestock | 87% | 35% | 9% | 1% | 1.6% | 1.1 days |
Wildlife* | 97% | 48% | 6% | 3% | 0.8% | 1.4 days |
Marine animals | 86% | 44% | 6% | 2% | 1.1% | 1.8 days |
Other/unspecified | 91% | 41% | 7% | 1% | 0.5% | 16.2 days |
Total | 88% | 37% | 7% | 2% | 0.7% | 2 days |
Notes:
# venomous animals may be included in other categories listed below, such as wildlife
* Wildlife excluding marine animals
Source: National Hospital Morbidity Database
By type of animal
Most venomous animals and insects are also categorised as wildlife, and the highest proportions of emergency admissions were for wildlife or venomous animal related injuries (Table 9). Injuries related to domestic animals (pets and livestock) were more likely to have overnight hospital stays, and pet related injuries had the highest average length of stay in hospital of cases with a specified animal type. Livestock injury cases were most likely to be transferred to other hospitals and wildlife injury cases to leave hospitals against medical advice, although proportions for these measures were low (under 10% of cases) across animal types.
Hospital management
Procedures undertaken during hospitalisation can provide further indication of both the severity of an injury and the resourcing required to treat it. Table 10 details the top 10 most frequent procedures recorded against cases hospitalised due to injuries caused by contact with animals. Allied health interventions, particularly pharmacy and physiotherapy, were frequently provided. For nonvenomous animals, surgical debridement and wound repair were frequent procedures, aligning with the fact that most injuries were open wounds or superficial or soft tissue injuries.
Procedure | cases | per cent (%) |
|---|---|---|
Venomous animal | 1,123 | 100 |
Allied health intervention, pharmacy | 163 | 14.5 |
General anaesthesia, ASA 10,20 or 29 | 101 | 8.9 |
Intravenous administration of pharmacological agent, antidote | 92 | 8.2 |
Allied health intervention, physiotherapy | 85 | 7.6 |
Debridement of skin and subcutaneous tissue, not elsewhere classified | 76 | 6.8 |
Debridement of soft tissue | 55 | 4.9 |
Incision and drainage of abscess of skin and subcutaneous tissue | 53 | 4.7 |
Allied health intervention, social work | 42 | 3.7 |
Nonvenomous animal | 40,753 | 100 |
General anaesthesia, ASA 20,10,29 or 19 | 6,750 | 16.6 |
Debridement of skin and subcutaneous tissue, not elsewhere classified | 5,560 | 13.6 |
Allied health intervention, physiotherapy | 3,033 | 7.4 |
Debridement of soft tissue | 2,646 | 6.5 |
Allied health intervention, pharmacy | 2,330 | 5.7 |
Repair of wound of skin and subcutaneous tissue of other site, superficial | 2,266 | 5.6 |
Allied health intervention, occupational therapy | 1,663 | 4.1 |
Notes: Cases caused by animals that could not be categorised by venomousness are excluded from counts presented in this table. Multiple procedures may be provided to a single case, and counts will not sum to the total number of cases presented in other tables in this report.
Source: National Hospital Morbidity Database
Envenomation and antivenom
Antivenom, also called antivenin, is a treatment that neutralises the venom of a particular animal or insect. Most bites do not result in significant envenomation and do not require antivenom, which is administered as soon as possible after identifying symptoms such as collapse, bleeding problems and muscle or nerve impairment (Isbister, Brown et al. 2013).
In hospitalised injury cases caused by venomous animals during 2021-22, 8.4% of cases had administration of a pharmacological antidote recorded. Antivenom administration in snakebite cases differed by snake species, with the highest proportion of administration occurring where snakes were unidentified (Table 11).
Type of snake | Cases (A) | T63.0# (B) | Antivenom administered ( C) | % of all cases with antivenom administered (C/A) | % of cases with T63.0# and antivenom administered (C/B) |
|---|---|---|---|---|---|
Brown snake | 200 | 54 | 26 | 13.0% | 48.1% |
Taipan | 3 | 3 | 1 | 33.3% | 33.3% |
Death adder | 4 | 2 | 0 | 0.0% | 0.0% |
Black snake | 82 | 19 | 4 | 4.9% | 21.1% |
Tiger snake | 39 | 23 | 13 | 33.3% | 56.5% |
Sea snake | 5 | 4 | 0 | 0.0% | 0.0% |
Other specified venomous snake | 12 | 2 | 1 | 8.3% | 50.0% |
Unspecified venomous snake | 190 | 58 | 41 | 21.6% | 70.7% |
Total | 535 | 165 | 86 | 16.1% | 52.1% |
Notes:
# T63.0 refers to a principal diagnosis of toxic effects of snake venom
Source: National Hospital Morbidity Database
AIHW (2023). Injury in Australia. Canberra, Australian Institute of Health and Welfare
Isbister, G. K., S. G. A. Brown, C. B. Page, D. L. McCoubrie, S. L. Greene and N. A. Buckley (2013). 'Snakebite in Australia: a practical approach to diagnosis and treatment.' Medical Journal of Australia 199(11): 763-768.