23.9 — Snake Bite, Insect Stings and Animal Bites

Do not cut the wound. Do not suck out the venom. Do not apply a tourniquet. Do not apply ice. Do not give alcohol. Do not try to catch the snake.

Every one of those is traditional advice, every one appears in films, and every one causes harm.

Snake bite kills an estimated 80,000 to 140,000 people a year and permanently disables around three times that many — mostly farmers and children in rural South Asia and sub-Saharan Africa, mostly without access to antivenom.

The World Health Organization classifies it as a neglected tropical disease, and the treatment that works is antivenom in hospital. Everything a bystander does is about getting the person there alive and minimising venom spread on the way.

Snake bite

What venom does

Broadly three kinds of effect, and many snakes produce more than one:

Cytotoxic — local tissue destruction. Severe pain, rapid swelling, blistering and tissue death. Vipers and adders.

Haemotoxic — attacking the clotting system. Bleeding from the gums, from the bite site, from old wounds, into the urine, and internally. Vipers, and Russell's viper in South Asia, which also causes kidney failure.

Neurotoxic — blocking transmission at the neuromuscular junction (Chapter 6.2). Drooping eyelids, double vision, difficulty swallowing and speaking, and eventually paralysis of the breathing muscles. Cobras, kraits, mambas, coral snakes, and Australian elapids.

And a specific and dangerous pattern: krait bites are frequently painless and may not be noticed. People are bitten at night while sleeping on the floor, wake with abdominal pain, and progress to paralysis. A bite mark may be invisible.

Myotoxic — muscle breakdown, causing rhabdomyolysis and kidney failure (Chapter 21.6). Sea snakes and some Australian species.

Dry bites — around 20 to 50 percent of venomous snake bites inject no venom at all. Which is why the absence of symptoms early is not proof of safety, and why observation is standard.

What to do

1. Move away from the snake.

Most bites happen when people try to kill, catch or handle a snake. Do not attempt it. A photograph from a safe distance is useful if it can be taken without risk. A description is enough.

A dead snake can still envenomate by reflex bite for up to an hour.

2. Keep them still and calm.

Physical activity and an increased heart rate speed venom spread through the lymphatic system.

Sit or lie them down. Carry them, or bring transport to them.

3. Immobilise the bitten limb.

Splint it as you would a fracture, and keep it at or below the level of the heart.

Immobilisation reduces lymphatic flow, and lymphatic flow is how most venoms travel.

4. Remove rings, watches, bracelets and tight clothing immediately, before swelling starts.

5. Call for emergency help and get to a hospital with antivenom.

This is the treatment. Everything else is holding ground.

6. Mark the edge of the swelling with a pen and write the time.

Repeat every 15 minutes. This gives the hospital a direct measure of how fast the envenomation is progressing, and it is genuinely useful information.

7. Monitor breathing and consciousness, and be ready to give rescue breaths.

Neurotoxic envenomation kills by respiratory paralysis, and assisted ventilation keeps people alive until antivenom works.

8. Clean the wound gently with water and cover it loosely.

Do not scrub.

What not to do, and why

Do not cut or incise the wound. It causes bleeding — dangerous with a haemotoxic venom — introduces infection, damages tissue, and removes no meaningful venom.

Do not suck the venom out, by mouth or with a suction device. Trials of suction devices found they remove a negligible fraction and cause local tissue damage.

Do not apply an arterial tourniquet. It causes limb ischaemia, and releasing it delivers a concentrated bolus of venom at once. Tourniquets have cost limbs and lives.

Pressure immobilisation bandaging — a firm crepe bandage over the whole limb plus a splint — is recommended in Australia for elapid bites, where the venom is neurotoxic and local tissue damage is minimal.

It is not recommended for viper bites, where trapping cytotoxic venom in the limb worsens tissue destruction. Which is why the advice differs by region, and why the local protocol matters.

Do not apply ice, which worsens tissue damage.

Do not give alcohol, aspirin or NSAIDs. Aspirin and NSAIDs worsen bleeding.

Do not use electric shock, herbal remedies, or a "snake stone". None of them work, and the delay they cause is what kills.

Antivenom

Antibodies raised in horses or sheep against specific venoms.

Specific to species or to groups of species, which is why identification matters.

Given intravenously in hospital, with the ability to manage an allergic reaction, which occurs in a proportion of cases.

And the global problem is supply. Antivenom is expensive, requires cold storage, and is unavailable in many of the places where snake bite is commonest. Some effective antivenoms have been discontinued for commercial reasons, which is a preventable cause of death.

Prevention

Wear boots and long trousers in snake country.

Use a torch at night — most bites occur at dusk or after dark.

Do not put hands or feet where you cannot see.

Sleep on a raised bed under a tucked-in mosquito net, which prevents a large share of krait bites.

Keep rodents away from dwellings, because rodents attract snakes.

And do not handle snakes, including ones you believe are dead or non-venomous.

Spiders and scorpions

Most spider bites are harmless.

Widow spiders — black widow, redback, and relatives. A neurotoxin causing severe muscle pain and cramps spreading from the bite, sweating, high blood pressure and abdominal rigidity that mimics a surgical abdomen. Rarely fatal in adults. Antivenom exists.

Recluse spiders — a cytotoxin causing a slowly enlarging necrotic ulcer over days to weeks. Frequently over-diagnosed — many lesions blamed on recluse spiders are actually bacterial infections, and in areas where the spider does not live, the diagnosis is almost always wrong.

Funnel-web spiders — Australian, genuinely dangerous, rapidly acting. Pressure immobilisation bandaging is specifically recommended, and antivenom is highly effective.

Scorpions — most stings are painful and not dangerous. Certain species in North Africa, the Middle East, Mexico, India and Brazil are dangerous, particularly to children, causing autonomic storm, breathing difficulty and heart failure. Antivenom exists.

General treatment: clean, cold pack, pain relief, and medical assessment if symptoms spread beyond the local area or the person is a child.

Insect stings

Bees, wasps, hornets, ants.

For most people: local pain, redness and swelling, resolving over hours to a couple of days.

Bee stings leave the sting and venom sac behind. Remove it as fast as possible by scraping sideways with a fingernail, a card or a knife edge.

Speed matters more than method — the venom sac continues to pump. Older advice against pinching it out is now considered less important than removing it quickly, and grabbing it is better than leaving it.

Wasps do not leave a sting and can sting repeatedly.

Treatment: cold pack, antihistamine, paracetamol or ibuprofen, and 1 percent hydrocortisone cream for itch.

When it is serious:

Anaphylaxis — the emergency, and adrenaline is the treatment (Chapter 23.5). Insect venom is a leading cause of fatal anaphylaxis in adults.

Stings in the mouth or throat — swelling can close the airway. Suck ice, and call an ambulance.

Multiple stings — hundreds of stings can cause toxic effects even without allergy, including muscle breakdown and kidney failure.

And venom immunotherapy is highly effective for people with confirmed severe insect venom allergy, reducing the risk of a future systemic reaction substantially.

Ticks

Ticks transmit Lyme disease, tick-borne encephalitis, and several other infections (Chapter 17.4).

Removal, done properly:

Use fine-tipped tweezers or a tick removal tool.

Grasp as close to the skin as possible.

Pull straight up, steadily, without twisting or jerking.

Clean the area afterwards.

Do not burn it, smother it with petroleum jelly, paint it with nail varnish, or apply alcohol. These make the tick regurgitate into the wound, which increases infection risk. Every one of them is traditional advice and all are wrong.

Transmission risk rises with attachment time — usually requiring more than 24 to 36 hours for Lyme disease, which is why prompt removal is the main prevention.

Watch for an expanding circular rash — erythema migrans — appearing days to weeks later, which is diagnostic of Lyme disease and needs antibiotics. Also flu-like illness, joint pains, or facial palsy.

Prevention: cover up, use repellent containing DEET, tuck trousers into socks, and check the whole body after being in long grass or woodland — including the scalp, behind the ears, the armpits and the groin, where nymphs are easy to miss.

Marine stings

Jellyfish, and the treatment differs by species, which is why local advice matters.

Box jellyfish and Irukandji — Australia and the Indo-Pacific. Extremely dangerous. Douse liberally with vinegar for at least 30 seconds, which prevents undischarged stinging cells from firing. Then remove tentacles and call for emergency help — antivenom exists for box jellyfish.

Portuguese man o' war and most other jellyfish — vinegar is not recommended for some species and may worsen the sting. Rinse with seawater — not fresh water, which triggers stinging cells to fire — remove tentacles with tweezers or a gloved hand, and immerse in hot water at around 45 degrees for 20 to 45 minutes, which denatures the venom and relieves pain.

Do not rub with sand, apply alcohol, or urinate on it. Urine has never been shown to help and may make it worse, and the sand rubbing fires more stinging cells.

Weever fish, stingrays, stonefish, lionfish, sea urchins — hot water immersion at 45 degrees for 30 to 90 minutes, because these venoms are heat-labile. Remove visible spines. Stingray and stonefish injuries can be severe, and stonefish antivenom exists.

Any marine puncture wound needs medical assessment — retained spines, deep infection with unusual marine organisms, and tetanus are all real risks.

Animal bites

And these are treated primarily as infection problems rather than as wounds.

Dog bites — crush and tear injury. Infection rate around 5 to 15 percent.

Cat bites — small deep punctures that inoculate bacteria deep and seal over. Infection rate 30 to 50 percent, and higher. Cat bites to the hand are particularly prone to serious infection and frequently need antibiotics and sometimes surgery.

Human bites — including the "fight bite", a knuckle laceration from striking someone's teeth. These are notorious, because the joint capsule is penetrated and the wound seals, producing a joint infection that can destroy the hand. Any knuckle wound sustained in a fight needs medical assessment, and the mechanism should be stated honestly.

Treatment:

Irrigate copiously with running water — several minutes at least. This is the single most effective thing you can do.

Do not close most bite wounds with stitches, because sealing bacteria in is worse than leaving the wound open. Facial wounds may be closed for cosmetic reasons with antibiotic cover.

Antibiotics are given for: cat bites; human bites; hand, foot, face or genital bites; deep or crush wounds; wounds over a joint; and bites in people with diabetes, immunosuppression, or no spleen.

Tetanus status checked (Chapter 23.3).

And rabies, which is the reason this matters most.

Rabies

Rabies is essentially 100 percent fatal once symptoms appear.

And it is essentially 100 percent preventable if post-exposure treatment is given before they do.

Which makes it one of the starkest treat-now situations in medicine.

Risk from: dogs, which cause the great majority of human cases worldwide; cats; bats; monkeys; foxes; and other mammals in endemic regions.

And bat exposure counts even without an obvious bite — a bat found in a room with a sleeping person or a small child is treated as an exposure, because bat teeth can leave marks too small to notice.

What to do after a possible exposure:

Wash the wound with soap and running water for 15 minutes.

That single step substantially reduces the risk of transmission, because the virus is fragile and the mechanical washing removes it.

Apply an iodine-based antiseptic if available.

Seek medical care immediately. Post-exposure treatment is a course of rabies vaccine, plus rabies immunoglobulin infiltrated around the wound for higher-risk exposures.

It works if started before symptoms — which typically appear weeks to months later — but it should never be delayed.

Pre-exposure vaccination is worth considering for travellers to endemic areas going somewhere remote, for a long stay, or working with animals.

And do not be reassured by an animal appearing well. Assess the risk with a doctor, not by looking at the dog.

Monkeys and other specific risks

Monkey bites and scratches, common in parts of Asia — carry rabies risk and also herpes B virus from macaques, which is rare and very serious. Wash immediately and seek care.

Rodent bites — low rabies risk in most places, and other infections are possible.

Snake handling, fish spines, and shellfish cuts — all carry unusual organisms and warrant a lower threshold for antibiotics.

The short version

Snake bite: stay still, immobilise the limb, mark the swelling, get to hospital. Cut nothing, suck nothing, tie nothing.

Bee sting: scrape the sting out fast, cold pack, and watch for anaphylaxis.

Tick: fine tweezers, straight up, no burning or smothering.

Jellyfish: seawater not fresh, hot water immersion, and vinegar only where local guidance says so.

Animal bite: wash for 15 minutes with soap and water, and get advice about rabies and antibiotics.

What the next page fixes

Chapter 23.10 covers heat, cold and drowning — three environmental emergencies where the correct action is different from what instinct suggests.