Australian snake bites

see also:

• Australian tiger and brown snake bites
• Mx of Australian snake bites with evidence of envenomation
• toxinology

• nearly all Australian venomous snakes belong to the Elapid family having colonised Australia c25 million years ago presumably evolving from an early sea krait
• they generally have short grooved fangs which allow their venom to be injected at bite sites hence thick trousers and boots are likely to be protective in preventing envenomation
• most snakes when they bite do not envenomate humans unless they are juvenile snakes or are substantially provoked by attempts to capture, inadvertently getting too close, or if stood upon
• their venom is amongst the most potently toxic in the world and causes a range of effects especially haematologic and neurologic but also some myotoxicity
• venom generally spreads from the bite site via lymphatic system - hence the pressure immobilisation technique for first aid
• the far majority of victims are able to get to hospital care where the may receive anti-venom but a very small minority can collapse soon after the bite and have cardiac arrest
• post-bite infection is extremely rare in Australian snake bites and seems more likely with taipan envenomations but still no where near the rate of infections seen in many other countries. ¹⁾
• fortunately there are no vipers in the wild in Australia - vipers cause thousands of deaths each year in Asia and Africa and have much longer fangs (which are hinged so they can fold when their mouth closes) than Australian snakes, and strike faster within 20-100msec which is faster than the mammalian startle response ²⁾
• there are only a few species of colubrids in Australia (many of which are non-venomous), these have fangs situated towards the back of their mouth, so they have a different biting style to the vipers and elapids and tend to hold onto victim longer making gaping cuts ³⁾
• the Australian rough-scaled death adder (Acanthophis rugosus) has the fastest bite time of Australian Elapid snakes of 30msec and moves during strike at up to 2.2m/sec - the 2nd fastest of the 36 snake species tested, and tended to bite repeatedly ⁴⁾
  • death adders can become active on warm (over 25degC) afternoons into dusk from Oct onwards in NSW

• ~550 people in Australia are admitted to public hospitals with snake bites each year, and there is an average of two deaths per annum. Approx. half of fatal snake bites occurred around the victim's home, ~70% of victims are male, and ~2/3rds of these fatal cases were caused by Eastern Brown Snakes ⁵⁾
  • to put this in perspective, over 50,000 people die each year from snake bites in India alone - even though Australian snakes have amongst the most potent lethal toxins, deaths are rare - mainly due to the availability of antivenom and widespread education not to try to catch them, how to reduce bite risks and how to apply first aid such as this: https://www.qld.gov.au/environment/plants-animals/animals/living-with/snakes
• there are ~100 envenomations by snake bites each year in Australia, and Eastern Brown Snakes account for 40% of all envenomations and collapsing, then having a cardiac arrest out of hospital was the most common cause of death (10 out of 23 deaths in this study published in the MJA in 2017), and most deaths were from brown snakes. 11% of snake bites victims were snake handlers and 14% of cases were due to trying to catch or kill a snake. 8% occurred whilst gardening. 14% occurred inside houses or buildings. ⁶⁾⁷⁾
• the three most common causes of venomous snake bite in Australia are brown snake family (~54%), black snake family (~14%), and tiger snake family (~11%) account for ~80% of all bites Australia wide ⁸⁾
  • in southern states such as Victoria and Tas:
    • nearly all bites are from eastern browns, red-bellied blacks and tiger snakes
    • a combination of daily temperatures and daylight hours in spring triggers southern snakes to wake up from their winter brumation and begin the breeding season.
      • tiger snakes only emerge from shelter once their bodies reached 16°C – provided it isn’t raining
      • alpine copperheads are frequently seen basking on hiking paths in the morning sun even when temperatures are below 10°C
  • in northern states such as Qld, NT, bites also occur from other snakes but to a lesser extent eg. taipan, death adder, mulga snakes and sea snakes
    • Qld is also home to more non-venomous snakes than other states - such as pythons and green tree snakes
  • in Western Australia, NT and Sth Aust, the western brown snake is also a cause of bites
  • only 2% occurred in forests and only 1% occurred at beaches with another 3% in countrysides including deserts - 34% occurred around homes, 7% occurred on farms
• venomous snakes in southern parts of Australia are generally NOT active at night unless it is a warm night
  • snakes are active when their body temperatures are between 28 and 32°C
  • snakes in the warmer northern parts of Australia tend to be more active at dusk and in warmer months, extend this into late evening (eg. mulga snake)
    • snakes avoid the harsh heat and are most active during early mornings, night time, and following the wet season (April to June)

• see https://www.aihw.gov.au/getmedia/2a017461-459d-43b2-b00e-4ddb0f1167e3/injcat110.pdf

• “brown snake” family (Pseudonaja sp)
  • most common in drier habitats
  • evolved c14 million years ago
  • very fast moving snake which causes most snake bite envenomations and accounts for over half of all snake bites in Australia
  • eastern brown snake Pseudonaja textilis
    • most of the eastern half of Australia's mainland including southern parts of Sth Australia, some regions in NT
    • not in WA or Tas, nor Phillip Island in Victoria
    • the second-most venomous terrestrial snake in the world
    • https://www.youtube.com/watch?v=CRHwqNoxpWU behaviour of eastern browns in bush land near houses in western Sydney including a dark banded juvenile
  • western brown snake or gwardar, Pseudonaja nuchalis
    • most of Australian mainland except most of Victoria, SE half of NSW, some of the Qld coastal areas
    • not in Tas or Victoria (apart from far NW Victoria)
• “black snake” family (Pseudechis sp)
  • envenomations are uncommon and deaths are extremely rare
  • evolved c17.5 million years ago
  • red bellied black snake Pseudechis porphyriacus
    • 14% of snake bites in Australia but deaths rare
    • most of SE Australia extending north to some coastal areas of Qld and west to Adelaide
    • not in Tas, WA, NT and not in most of Sth Aust, NW parts of NSW or inland Qld
    • most common in riverine areas or swamps
    • can remain submerged under water for 45 minutes or so and are generally good swimmers
  • mulga snake or king brown Pseudechis australis)
    • 4% of snake bites in Australia - last death was in 1969
    • most areas not occupied by red bellied black snakes
    • not in Tas, Vic, eastern NSW, Fleurieu Peninsula Sth Aust or SW corner of WA
    • now rare in coastal Qld
    • can inhabit woodlands, grasslands, deserts, vacated buildings, waterways
• tiger snake family (Notechis sp)
  • most common in riverine or coastal areas
  • evolved c12 million years ago
  • 11% of snakebites in Australia
  • mainland tiger snake Notechis scutatus:
    • most of Victoria, southern and eastern parts of NSW, small areas in SE Sth Aust, small area in SE Qld
    • not in Tas, WA, NT, most of Qld, most of Sth Aust
  • black tiger snake Notechis ater
    • mainly Tas, Bass strait islands, parts of central coast of Sth Aust and SW WA
    • not in NT, Qld, NSW, Vic, most of Sth Aust, most of WA
• copperhead snake family Austrelaps sp
  • https://australian.museum/learn/animals/reptiles/copperhead/
  • generally a placid species which rarely bites humans but does have toxic venom
  • evolved c12 million years ago
  • Pygmy Copperhead Austrelaps labialis
    • only found in the Mount Lofty Ranges east of Adelaide and on Kangaroo Island
  • Highland Copperhead Austrelaps ramsayi
    • alpine highlands of NSW and eastern Vic
  • Lowland Copperhead Austrelaps superbus
    • lowland areas of southeastern South Australia, southern Victoria, Tasmania, and the islands of Bass Strait
    • coastal areas and farm lands in particular
• taipans (Oxyuranus sp.)
  • mainly Qld, NT
  • evolved c14 million years ago
• death adders (Acanthophis spp.)
  • mainly Qld, NT
• many less common snake species rarely involved in bites
• sea-snakes (families Hydrophiidae and Laticaudidae)

• 50% of fatal snakebites occurred around a victim's home
• minimise places of shelter around your home
  • remove rubbish, ensure wood piles are stacked tidily
• reduce food sources
  • avoid food scraps or bird seeds which attract rats and mice
  • avoid having chook pens or bird aviaries as snakes do like eggs
• warm areas such as greenhouses attract snakes
• if you are paranoid, don't have a home near waterways or bushland

• keep lawns cut short
• most snakes prefer to avoid prolonged exposure away from shelters which risks them being attacked so short lawns also discourage them

• ~14% of snakebites occur inside homes or buildings
• all venomous snakes can flatten to squeeze through gaps under doors or through small holes in timber walls or holes in meshed windows
• some snakes get into houses by being brought in with bags or shoes from outside - some even find their way into cars!

• wear gloves, long pants and covered shoes
• lift objects so that they face away from you

• < 8% of bites occur in forest, beach or countryside areas but if you walk for more than 2hrs in higher risk areas there is a reasonable chance you will see a snake on your path and these can be easily avoided if you see them
• stick to wide paths where possible and keep a close eye out at all times
• take pressure bandages on EVERY bush walk and know how to apply them
• if possible walk with someone else so they can call for help
• particularly if walking narrow paths or in long grass, wear thick long trousers and sturdy boots - or consider thick knee high gaiters and boots if wearing shorts
• if walking in remote areas solo, ensure you have a remote communication device such as a satellite messaging service or an EPIRB radio beacon - you should not walk after you get bitten!
• LOOK before you walk over logs fallen across paths
• avoid leaving boots and similar outside your tent - and check them before putting them on
• on warm nights in particular, carry a torch to see where you are going
• take extra care looking for firewood - snakes like to live under or inside fallen logs
• if camping, keep you tent mesh doors fully closed when humans are not around - although snakes entering tents or swags is extremely rare

• see first aid and Mx of suspected Australian brown and tiger snake bites
• see Mx of Australian snake bites with evidence of envenomation