Venomous creatures in western Victoria: What to expect and how to respond
In January this year, a 24-year-old man from Tamworth, in north-western New South Wales, died less than an hour after being bitten by a brown snake. This tragedy is a timely reminder that snakes are most active, and therefore most likely to come into contact with humans, in the warmer months.
Australia’s many other venomous creatures include insects, spiders and various aquatic animals, and contact with them is generally also more common in the warmer months, when we spend more time outdoors. Happily, rates of serious illness or death following a bite or sting from a venomous creature are low in Australia.
In this article, we look at the venomous creatures we’re most likely to encounter in western Victoria, how to react and the treatments available.
Epidemiology and pathology of envenomation
Envenomation is the process of being poisoned through the bite or sting of a venomous creature. Between August 2001 and May 2013, 41 521 people were admitted to hospital following envenomation in Australia, a population rate of 199 admissions per 100 000 people (0.2 per cent) per annum. Contact with venomous wasps, hornets and bees accounted for 31 per cent of admissions, spiders 30 per cent, and snakes or lizards 15 per cent.
The National Coronial Information System lists 64 deaths due to a bite or sting from a venomous organism in the period 2000–13 – an average of less than five per year. Fifty-eight deaths (91 per cent) occurred between the months of October and April. Snake bite envenomation caused 27 deaths (less than two per year), and bees 25, wasps two, ants two and ticks three.
Snake venom can cause blood clotting and life-threatening haemorrhages, as well as acute kidney injuries, brain and muscle damage and cardiac arrest. The major health risk associated with a bite or sting from an arthropod (bees, jumper ants, ticks, fire ants and wasps) is anaphylaxis.
Allergic reactions and anaphylaxis
Venoms from bees, jumper ants, ticks, fire ants and wasps can cause anaphylaxis, which is the most serious allergic reaction and can cause death if prompt medical attention does not occur. Within minutes of exposure to the allergen, or ‘trigger’, the person can have potentially life-threatening symptoms such as breathing difficulties.
Symptoms of anaphylaxis include:
- Facial swelling, including swelling of the lips and eyelids
- Swollen tongue
- Swollen throat
- Reddening of skin across the body
- Hives (red welts) appearing across the skin
- Abdominal discomfort or pain
- Strained or noisy breathing
- Inability to talk or hoarseness
- Wheezing or coughing
- Drop in blood pressure
- Floppiness and pallor in young children.
Most of the information presented here is adapted from the Victorian Government’s Better Health Channel.
In general, first aid involves bandaging the wound and keeping the person immobile until medical help arrives. The pressure immobilisation method (designed to slow the movement of venom through the lymphatic system) is ideal for bites from Australian venomous snakes (as well as those from blue-ringed octopuses), but not for other bites and stings (see below).
If you don’t have bandages, use whatever is available, such as clothing, stockings or towels. Firmly bandage the wound but not tight enough to cause numbness, tingling or colour change in the extremities. Only remove the bandage in a medical facility, as the release of pressure will cause a rapid flow of venom through the bloodstream.
Immobilising the limb is another way to slow the spread of venom (because the lymphatic system relies on muscle movement to squeeze lymph through its vessels). Splint the limb if necessary.
Try to keep the person calm and reassured. Don’t use a tourniquet or cut the wound.
Always seek immediate medical help and call triple zero (000) for an ambulance in an emergency. If the person collapses or stops breathing, you may need to apply cardiopulmonary resuscitation (CPR) until medical help arrives.
Don’t wash the skin following a snake bite, as traces of venom might be needed to identify the snake. Capturing the animal or insect for identification purposes is no longer recommended. On 5 October 2017, the Royal Flying Doctor Service released the following advice: ‘Staying in the area after an attack can be dangerous and recent advances in medication mean we can now treat any snakebite with a generic polyvalent anti-venom, so identification is no longer necessary’.
People who have been diagnosed as particularly vulnerable to anaphylaxis should carry an adrenaline auto-injector (AAI) at all times. In Australia, the two brands of AAI devices are EpiPen and AnaPen, available on prescription and incorporating detailed instructions (also given on the Australasian Society of Clinical Immunology and Allergy website). It is important to understand that the administration is very different for adults and children.
Although state-based and regional figures are not available, the snakes responsible for most bites in western Victoria are almost certainly the common or eastern brown snake, the mainland tiger snake and the red-bellied black snake. In 718 attacks across Australia between 2005 and 2015 in which the snake was positively identified, 41 per cent involved a brown snake, 17 per cent a tiger snake and 16 per cent a red-bellied black snake. All three species are found throughout western Victoria. Most snake bite fatalities occur around people’s homes within major cities or inner regional areas.
Brown snakes caused 63 per cent of all snake bite deaths in Australia between 2000 and 2013. A brown snake’s diet includes mice and rats, so it is often found close to dwellings, barns and sheds that house rodents. It is active during the day, and can be fast and aggressive if cornered (Sutherland & Sutherland, 1999).
Tiger snakes hunt for frogs and small rodents on warm evenings, and can come into contact with humans on riverbanks, around dams and farms, and in outer urban backyards. They are rarely aggressive unless provoked (Sutherland & Sutherland, 1999).
The red-bellied black snake inhabits riverine or swampy country. It hunts during the day, catching rodents, fish, eels, frogs, lizards and birds. This shy snake has not caused any confirmed deaths in adults (Sutherland & Sutherland, 1999).
Treatment for snake bite
Most of the information in this section is reproduced from the Australian Venom Research Unit’s website.
Only one in 20 snake bites require active emergency treatment or the administration of antivenom, but every snake bite should be managed as a medical emergency until resolved, even if the patent seems well initially. Medical management depends on the extent of envenomation, the effectiveness of first aid bandaging (see above) and the type of venom.
The Australian Snakebite Project included 1548 patients with suspected snakebites, including 835 envenomed patients (median, 87 per year). Antivenom was given to 755 patients; 178 (24 per cent) had allergic reactions, of which 45 (6 per cent) were severe (hypotension, hypoxaemia).
High rates of allergic reactions to antivenom have been cited as the reason many rural practitioners apply first aid in the case of snakebite before transferring the patient to a larger regional centre. In an ABC News interview, Sandy Grieve, chief executive of Walwa Bush Nursing Centre (near Albury in north-western Victoria), was quoted as saying that ‘We stopped stocking antivenom three years ago. We had previously [stocked it] for 30 years … in the 30 years I’ve been here, we’ve never seen a snakebite that included or involved envenomation. The majority of practitioners are a little wary of using antivenom, particularly in remote areas, because of the risk of anaphylaxis and risk of serious reactions.’
However, the head of the Australian Venom Research Unit, Dr David Williams, warned that there could be a rise in snakebite fatalities if hospitals did not maintain appropriate stocks of antivenom. He recommended that every hospital have supplies of antivenom for the treatment of at least two cases of snake bite at the same time, or an effective treatment plan. Dr Williams said it was important to ‘ensure all the bigger district hospitals have supplies and the smaller feeder hospitals have contingency plans for the rapid transfer of the patient to the district hospital or the transfer of the antivenom.’
Red-back spiders are found in almost all parts of Australia and are particularly common in summer (Sutherland & Sutherland, 1999). The females (who deliver all bites) spin webs in dark, quiet locations such as under houses or in piles of wood or rubbish. They are rarely aggressive but will bite when touched, stood upon or otherwise trapped against the skin. The bite is initially no worse than a minor insect sting, but within a few minutes becomes intense and spreads across the body.
Treatment for red-back spider bite
Wash the affected area well and soothe the pain with icepacks or iced water. Do not bandage the area. Antivenom can be effective days or even weeks after the bite (Sutherland & Sutherland, 1999).
Bees and wasps
Honey bees are found Australia-wide, wherever there is pollen (Sutherland & Sutherland, 1999). Allergic reactions and anaphylaxis (see below) are the major health risks from bee stings.
Treatment for bee sting
Remove the sting by scraping your fingernail across it, rather than pulling at it (pulling can force the release of more venom from the sting sac). Wash the area and apply ice to reduce the swelling. If the person is allergic to bee sting, they can enter a life-threatening state of anaphylactic shock; the only treatment is an injection of adrenaline (see Allergic reactions and anaphylaxis below). Immobilise the person, apply pressure to the bite and seek immediate medical help.
The European wasp is an introduced species with no natural predators in Australia. Moreover, cold winters in its native territories kill all but the Queen wasp, but the warmer climate of Australia allows the entire nest to survive. European wasps are far more aggressive than native wasps, and like to live near humans because of the ready supply of (particularly sweet) food and drink. They occur throughout most of Victoria.
Treatment for European wasp sting
Clean the affected area with soap and warm water. Use an icepack to reduce swelling and pain. Use pain-relieving medication and creams. Be alert for allergic reactions (see below). Prolonged swelling at the site of the sting may respond to antihistamines – see a pharmacist for further advice.
Species of venomous jellyfish that inhabit Victorian waters include the jimble, bluebottle, mauve stinger and hairy stinger (Sutherland & Sutherland, 1999). None of these has caused death in Australia to date, but several people have died overseas following bluebottle stings, and eye damage can occur. Contact with the tentacles typically produces a burning sensation and pain that can last up to two hours.
Treatment for jellyfish sting
The blue-ringed octopus inhabits all Australian coastal waters (Sutherland & Sutherland, 1999). It hunts at night in shallow water, and is very unlikely to bite a human unless handled. Envenomation causes tingling in the tongue and lips, then difficulty in seeing and breathing, and vomiting and collapse in approximately 10 minutes. The paralysis can cause breathing to stop, followed by death.
Treatment for blue-ringed octopus bite
Seek immediate medical help. You may need to perform CPR, and even it seems futile, continue until medical help arrives. The pressure immobilisation bandage method is suitable for blue-ringed octopus bites.
Serious illness or death following a bite or sting from a venomous creature is uncommon in Australia, but prompt and appropriate treatment is important to reduce harm as much as possible.
Sutherland S & Sutherland J, 1999, Venomous creatures of Australia: A field guide with notes on first aid. Melbourne: Oxford University Press.