Snakebites In Remote Locations

I started writing this article many months ago, after I was bitten by a Brazilian Wandering Spider (which is in the Guinness World Records as the most dangerous spider!). The spider fortunately decided only to dry bite (not to envenomate) but it raised the question: Just how prepared am I to deal with envenomation in remote parts of Ecuador?

A Brazilian Wandering Spider in a defensive stance.

I liked to think that I was ready if a real incident occurred; I had read advice and have some medical supplies and training. When I considered the process of evacuation to a hospital however my readiness came up wanting. When I researched to try and solve the problems I encountered conflicting advice.

This article is about how I would deal with envenomation in remote Ecuador where evacuation to a hospital is not possible. I will emphasise that I use the first person throughout this article for I am not certified to provide medical advice and am only stating what I would do.

To begin though, I will explain some background to understand why contradictions exist. And I’m going to start with snakes as they are the most consequential.

Antivenin

Traditionally, when I go to a hospital and say ‘ow, my snakebite hurts’, they would give me antivenin. No that’s not a typo, but so many people mishear the word that even some official sources use “antivenom” now so that people can easily find information on the internet in a panic.

Milking venom from a snake to be used to create antivenin.

Antivenins are produced by injecting regular, small amounts of venom into [what is usually] a horse. Horses are very forgiving to being pricked repeatedly by people in lab coats which is why they are the preferred choice. Blood is then drawn from the animal and the plasma separated from the blood by centrifuge. People with allergies to horses may therefore have a reaction to the serum, albeit if this is the case often only minor. For the few who do not believe that vaccinations work antivenins are an excellent example of confirmed envenomated patients having magnitudes higher survival rate with antivenin, through the process of vaccinating a horse.

There are broadly two genus of venomous snakes in Ecuador; Coral Snakes which have a neurotoxic venom, and Pit Vipers, which have a hemotoxic venom. Coral snake antivenin is no longer being manufactured due to the high cost of development. Bites from such snakes are rare but as the majority occur in developing countries there is little financial incentive for pharmaceutical companies. The stockpile that exists in the USA expired originally in 2008 but the date has repeatedly been extended for lack of alternative. In the absence of coral snake antivenin elective endotracheal intubation (a tube in the airway) and mechanical ventilation (a machine to assist breathing) are used effectively.

Neurotoxins work by inhibiting the nervous system in different ways, but typically resulting in numbness or paralysis, fatalities normally resulting from respiratory paralysis. Hemotoxins however target and damage specific organs or cells. This is damage, rather than inhibition, so cannot be reversed by antivenin which can only prevent further damage from occurring. This kind of toxin causes organ failure and internal bleeding; essentially the venom is digesting you to make consumption easier for the animal.

The Usual Suspects

A pit viper with it’s iconic ace-of-spades shaped head and thin tail compared to body.

Pit Vipers (Bothrops, Both-) are called so because of a heat sensitive pit located on each side of their heads, between the eye and nostril. Species include Lanceheads, Toadheads and Hognoses which are typically no longer than a meter and have the iconic spade-shaped heads of vipers. Pit Vipers can control the amount of venom they inject in a bite – if any at all – particularly if there are multiple threats that might require biting. Even if a species is capable of this control juveniles are less practiced however, so you may more likely recieve a stronger dose from a young snake (contentious topic!). There is a 7% fatality rate for untreated victims and 2% fatality rate with antivenin. The primary cause of death is hypotension (weak blood pressure) from internal bleeding.

The Fer-de-Lance (B. Asper) or equis in Ecuador, is a snake of particular repute and has been referred to as the “ultimate pit viper”. It is fast moving, irritable, unpredictable and responsible for the majority of snake bites in the Amazonian countries. It is large at two meters, often rearing up to strike above the knees and is capable of spraying venom (at a distance of 1.8m!).

Bushmaster.

This final Pit Viper to mention however is the most feared snake in the neotropics. The Bushmaster (Lachesis), is a sub-genus of Bothrops and is known as verrugosa in Ecuador. This snake is colossal in size, growing up to three meters making it one of the longest venomous snakes in the world. Not only are they aggressive but they are capable of multiple-strikes; rapid bites to inject venom into as much of the body as possible. The venom has a similar potency to the Common European Adder (the only venemous snake in the UK), but whereas that snake has a yield of only 12mg, a Bushmaster can deliver 500mg of venom in one bite. With treatment, there is still an 80% fatality rate with survivors often requiring amputation due to necrosis (rapid cell death, no picture here as it is horrific to see!). Encounters with these snakes are however extremely rare.

Venom Measures

Venom is measured by mass rather than volume to make it easily comparable to a prey’s or person’s mass.

A coral snake, demonstrating the typical slender body and featureless head. Almost all have coloured banding like this one. We can tell this is South American as it is neither “red to yellow” or “red to black”.

Of the eighty species of Coral Snakes (Micrurus) in the world, fifteen exist in Ecuador and are simply referred to as coral in the country. Although they produce tiny amounts of venom for a snake at 5mg on average, the LD50 (lethal dose for 50% of people) is only 1-3mg depending on the specie. They cannot control the amount of venom they administer like Pit Vipers however, meanings you would always receive the full amount. This said, 40% of bites do not envenomate because corals dribble their venom outside of their fangs, unlike Pit Vipers with their hollowed, needle-like fangs. My data is deficient on treated survival rate compared to untreated but 10-20% of bites are said to result in fatality (so likely 24-48% of envenomated bites), death occurring between 2 and 26 hours after the incident. These are however reclusive snakes and reluctant to bite. Some harmless snakes imperfectly mimic coral snakes to deter predators. The rhyme “red to black, friend of jack; red to yellow, kills a fellow” refers to the colour banding, however this only applies to North American species and NOT South American.

LD50

LD50 stands for the Lethal Dose for fifty percent of people. It is typically tested on mice and is used as a standard for everything, from drugs to toxins. The data in this article only refers to the LD50 for an IV (intravenous) administration, so by injection like a bite.

It’s worth noting that occasionally the Yellow-Bellied Sea Snake ventures the Ecuadorian coast. These have a ridiculously lethal cocktail of hemotoxin and neurotoxin. Fortunately, costal areas tend to have access to hospitals.

Treatment

There is a lot of conflicting advice when it comes to treating snake bites for four reasons:

  1. Hemotoxic and neurotoxic symptoms are different;
  2. Assumptions of accessibility to medical facilities;
  3. Medical advice is revised or issues remain contentious, and;
  4. A lack of trust in the public to follow anything other than the simplest guidelines.

The general advice is as follows:

  • DO note the snakes appearance;
  • DON’T cut or bite the wound;
  • DO raise bitten body part above heart if possible;
  • DON’T wipe or wash the wound;
  • DO elevate the wound above the heart if possible;
  • DON’T apply tourniquet, ice or water;
  • DO keep them calm and at rest;
  • DON’T give the person alcohol, nicotine or caffeine, and;
  • DO remove jewellery near the wound, or remove shoes if bitten on the leg.

If I have no means of medical evacuation than rest and laying down is contrary to common sense of finding help.

Strangely, I’ve read advice not to use electricity as treatment. Although I consider this generally good life advice, I have no idea what the circumstances were that this has to be stated.

Pressure bandaging.

A tourniquet should never be applied as this creates additional problems and allowing the venom to dilute around the body can be beneficial. A pressure band (essentially a loose tourniquet) remains one of these contentious topics. Some advice says to apply one if more than an hour away from a medical facility, to be loosened with swelling but once on only to be taken off by a medical professional. Other advice says that this concentrates the venom in an area increasing cell damage, which sounds like a reference to hemotoxin. I would therefore pressure bandage neurotoxic venom, but would not however apply a pressure band due to envenomation from something minor such as a Brazilian Wandering Spider, as I consider there to be no threat to life to a healthy adult. If I am by myself, envenomated with hemotoxin, I would (as well as review my life choices) pressure band to make myself as functionally useful as possible. This increased risk of requiring a limb amputated (assuming I survived my life choices) I would not take otherwise with hemotoxin.

Venom suction pump.

Venom suction pumps placed over the wound and then drawn like a hypodermic needle were common accessories to first aid kits. Then the US decided this was wrong but now they are debating them again. The issue is the localisation of hemotoxin again. If you are successful and draw the hemotoxin to the pump then you are concentrating the venom around the wound. Medical professionals will use the device for no longer than one minute, so the revision must be a distrust of the public to follow this same guideline. I would use a suction pump as the professionals would.

I have read explicit advice by some authorities saying to never wipe or wash the wound, as the trace venom on the skin can be used for a positive identification. Other sources say to apply loose bandaging, which as well as inevitably wiping the wound, seems like a negligible way to reduce infection to a closed puncture wound/s. Pit Viper bites are all typically treated with a polyvalent called CoFab (sheep serum) whereas all Coral Snake bites are typically treated with the aging polyvalent called Wyeth (horse serum). So long as you can tell the difference between a Pit Viper and a Coral Snake I would not otherwise allow keeping the wound juicy to impede other procedure.

Remote Locations

I would always try to get to a hospital. If I’m a day – more or less – from one, I’ll be riding the full effects so would in my mind know that my mortality rests solely with how I treat myself (although I would still be making my way to a hospital).

Hypotension (Hemotoxin): The hypotension is caused by internal bleeding, so I would take measures to reduce this. Anticoagulants (prevents the blood from clotting) such as Aspirin, should NOT be used. Antihemorrhagics (which promote coagulation) are therefore more beneficial than not taking them. Drugs that contain Fibrinogen or Vitamin K are used for systemic purposes (the whole body). Fibrinogen only has a half life of 100-150 hours and is harder to get than antivenin so you might as well have nabbed CoFab; however you can buy Vitamin K supplements easily. Menadione is a common supplement used around the world, administered to babies, animals and everyone in between. Be wary that other antihemorrhagic agents – such as anything labelled as a styptic – are designed to be applied to wounds and have only local effects, so are little benefit to internal bleeding.

It would take my body 5-8 hours to make use of orally administered Vitamin K, so is a long time for this purpose. There are no recommendation on self-treatment in remote locations by an accredited medical professional for they would be lending their reputation to a desperate situation that they have no control of. Menadione may be like throwing a bucket of water on a forest fire therefore – or it could just save my life. Phytonadione is an intravenous (injectable) Vitamin K supplement, however I would keep clear of this as even medical professionals have caused fatalities with its use.

Activated charcoal is the name for medical grade, although regular charcoal works as well.

Respiratory Paralysis (Neurotoxin): I see no way of treating this in a remote location, by myself. With an additional person, assisting the casualty to breath is the aim, so performing CPR is better than not doing so. Brain death occurs after several minutes but if they regain a pulse but remain unconscious I would continue to do compressions only (potentially for hours!).

Charcoal (All toxins): This has surprisingly many medicinal uses and is the first go-to by US medical professionals regarding general toxins. It is an aDsorbent (not aBsorbent) to which toxins bind with and is used in primary care in the US for treating toxins. You can make a pulpous (crushed, wet substance applied to skin with a bandage) and drink a solution of charcoal boiled in water and then filtered. It tastes better than bad coffee (to set a low bar) and you can drink litres of the stuff safely. I will dedicate an article to this subject alone at a later date in more detail.

Species Specific

Now I have explained my approach to dealing with envenomation in a remote location, I will conclude with sample data of venomous animals.

Hemotoxic Examples:

Recluse Spider, Bushmaster Snake, Beaked Sea Snake, Mexican Beaded Lizard, Carpet Viper, Russel’s Viper, Tiger Snake, Eastern Brown Snake, Puff Adder.

Neurotoxic Examples:

Black Widow Spider, Brazilian Wandering Spider, Australian Funnel-Web Spider, Beaked Sea Snake, Inland Taipan, Common Krait, Tiger Snake, Common Death Adder, Eastern Brown Snake, Black Mamba

Microgram (µg)

A milligram (mg) is one-thousandth of a gram and a microgram (µg) is one-millionth of a gram.

Sample Data

img_1104-1
Fer-de-lance.

The following are some examples of venomous animals from around the world and their lethality:

  1. Brazilian Wandering Spider: Average yield 134 µg/kg, delivers venoms only 1 in 3 bites, and rarely full dose. Defensively stands ground but not aggressive. Death is unheard of for healthy adults but can cause a “painful erection” in men that may lead to impotence.
  2. Yellow-bellied Sea Snake: Average yield 4.4mg, LD50 6.3mg (mice, 0.09mg/kg)
  3. Beaked Sea Snake: Average yield 8.5mg, LD50 2.2mg (mice, 0.1125mg/kg)
  4. Southern Coral Snake: Average yield 30mg, LD50 52.5mg (mice, 0.75mg/kg)
  5. Eastern Coral Snake: Average yield 5mg, LD50 14mg (mice, 0.2mg/kg)
  6. Atlantic Bushmaster: Average yield 500mg, LD50 420mg (mice, 0.9mg/kg). Multiple-strikes, 3.5cm long fangs, aggressive. Fatality rate 80% with antivenin!
  7. Fer-de-lance: Average yield 1,530mg, LD50 82.25mg (mice, 1.175mg/kg)
  8. European Adder: Average yield 12mg, LD50 38.5mg (mice 0.55mg/kg)
  9. Puff Adder: Average yield 750mg, LD50 27.23mg (mice, 0.389mg/kg), death by 25 hours)
  10. Common Death Adder: Average yield 152mg, LD50 35mg (mice, 0.5mg/kg)
  11. Carpet Viper: Average yield 20mg, LD50 10.5mg (mice, 0.15mg/kg)
  12. Russel’s Viper: Average yield 190mg, LD50 52.5mg (mice, 0.75mg/kg)
  13. Cottonmouth: Average yield 180mg, LD50 170mg (mice, 2.25mg/kg)
  14. Black Mambas: Average yield 85mg, LD50 22.4mg (mice, 0.32mg/kg)
  15. Eastern Brown Snake: Average yield 10mg, LD50 2.52mg (mice, 0.036mg/kg)
  16. Tiger Snake: Average yield 112mg, LD50 14.7mg (mice, 0.21mg/kg)
  17. Common Krait: Average yield 30mg, LD50 2.8mg (mice, 0.04mg/kg)
  18. Inland Taipan: Average yield 77mg, LD50 1.75mg (mice, 0.025mg/kg)
  19. Mexican Beaded Lizard: Average yield 0.5mg, LD50 140mg (mice, 2mg/kg)

Note that venom yields and potency seems to vary from source to source by up to tenfold in potentially either direction of the statics given. I find the most noticeable discrepancy is comparing the coral snakes with their higher fatality rate, to pit vipers which seem to have greater lethality according to these numbers. The data given should be considered with scrutiny.

Special Mention

All Poison Dart Frogs are colourful for they have no need to hide.

Poison Dart Frog (Dendrobatidae) are the most toxic animals in the world. The origin of their name is derived from their use of indigenous tribes to coat their blowdarts with the frog’s poison. They mostly sequester this poison from their arthropod prey, resulting in captive specimens having magnitudes less toxin. There is an estimated lethal injection dose of 2.0 to 7.5 µg for humans and large frogs are able to secrete 40 µg. When administered orally (and/or cooked), the toxicity is much lower, making safe for Amerindians to consume animals hunted with the poison darts. Other symptoms of intoxication include muscle and respiratory paralysis, strong muscle contractions, convulsions and salivation.

There are 5g (0.176 oz) of water in a teaspoon, which is equal to 5,000mg or 5,000,000µg. This means that for a teaspoon of toxin 125,000 large frogs would have to be “milked”, but this teaspoon could kill 2,500,000 people.

If you have any questions or comments, please do not hesitate to contact me.

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