Step 1. Protect yourself. The first step in wound care is to protect yourself from blood-borne pathogens, including HIV and Hepatitis B.

Bare foot meets carelessly tossed machete

Always assume that all body substances are infectious.

Wash your hands before and after any wound contact, either with soap and water or — even better — an alcohol gel, such as those made by Purell or Lysol.

Carry some exam gloves in your medical kit, and put them on for any anticipated contact with nonintact skin, blood, body fluids, mucous membranes, or contaminated items. Wash your hands immediately after you remove the gloves.

Protect your own mucous membranes — eyes, nose, and mouth — from blood splash. Tie a bandana around your face, and put on your glasses.

Step 2. Stop the bleeding. The second step in wound care is to stop further blood loss. Apart from an obstructed airway, nothing else matters until the flow of blood is stopped.

Apply direct pressure on the wound to stop bleeding

In almost every case — even in amputations — bleeding can be stopped by elevating the wound above the level of the heart and applying strong direct pressure for about ten to fifteen minutes. Blood is slippery, so use a piece of gauze, preferably sterile, or even a clean bandana if that is all you have; a Kotex pad tossed in your medical kit is ideal for this purpose. Put your thumb or fingers or your whole palm over the wound and press down hard; alert and cooperative patients can do this themselves. If the gauze gets soaked with blood, do not remove it, but add more gauze.

Do not use a tourniquet. Tourniquets kill limbs. There may be occasions when a tourniquet is necessary, such as massive shrapnel wounds, but using a tourniquet is a deliberate decision to sacrifice a limb in order to save a life.

Step 3. Clean the wound. The third step in wound care — especially in the jungle — is to make sure the wound is as clean as you can possibly make it.

Clean the wound with an irrigation syringe …

Remove any existing bandages or wound closure strips.

Clean the skin around the wound with soap and water or a topical antiseptic such as povidone iodine. Scrub gently with a sterile gauze pad. The idea is to remove any dirt that might seed the wound with bacteria. Avoid getting soap or antiseptic in the wound itself. Scrub in a spiral pattern away from the wound rather than toward it.

Allow the wound to open naturally. If necessary, spread the wound edges apart using a pair of sterile forceps.

If the wound has become infected, pus has probably collected in pockets, so gently probe the deeper parts of the wound with a sterile instrument to make sure that all such pockets are drained.

Irrigate the wound copiously with a high-pressure stream of purified water to remove clotted blood, pus, debris, and other contaminants. Use an irrigation syringe and splash shield; in an emergency, you can use any sort of clean plastic bag with a pinhole punched in it, or melt a pinhole in the top of a standard water bottle, but protect yourself from blood splash.

… preferably one with a splash shield

The primary medium for infection within a wound is dead tissue. Dead tissue is basically meat. It has no blood supply; white cells and antibodies have difficulty penetrating it; and thus it is a good culture medium for bacteria and fungi. You can identify living tissue because it is reddish, elastic, and bleeds when you poke it; dead tissue is dark, mushy, and does not bleed. Look for dead tissue in the wound. If any remains after high-pressure irrigation, then — unless a relatively brief evacuation is imminent — it must be removed or debrided. In a wilderness emergency situation, your best bet is to scrub the wound with sterile sponges, sterile dressings, or sterile pieces of cotton. Rough cloth works better than smooth cloth. Scrub with firmness. It will hurt. Your friend will use very bad language. The wound will bleed again, since clots will have been knocked off, but the bleeding can readily be stopped by direct pressure with a sterile dressing.

Always follow any debridement with additional high-pressure irrigation. The wound should be clean and pink.

A cleaned and debrided wound

Step 4. Protect the wound. Once the wound is cleaned of dirt, debris, pus, and dead tissue, the fourth step is to dress the wound to provide a healing environment and prevent further contamination.

A dressing is any material applied to a wound to control bleeding and prevent contamination; a bandage is any material used to hold a dressing in place. Think about dressings and bandages in layers. Immediately next to the skin should be a nonadherent base — Telfa, Second Skin, Xeroform, a piece of sterile gauze impregnated with petroleum jelly — that will not stick to the wound. Above that should be a gauze sponge to absorb wound discharge. Those two layers should be held in place by bandaging material that either sticks to itself or is attached to the skin with adhesive tape.

Dressings and bandages are often sold as a combined adhesive wound covering. A simple Band-Aid is a good example — neat, versatile, and sterile.

Apply a dressing …

If you were not in the middle of the jungle, it might make sense to use butterfly strips or Dermabond tissue adhesive to bring the edges of the wound together and minimize scarring. But closing the edges of a wound can create a deep dark warm pocket in which bacteria can grow and form an abscess. At this point, avoiding an abscess should be a higher priority than minimizing a scar.

A goal of the dressing is to keep the wound moist and create an environment that encourages healing. Current nonadherent dressing materials — including sterile gauze impregnated with petroleum jelly — are designed to provide such an environment. You can also apply a thin layer of antibiotic ointment, which helps keep the wound moist, and may — or may not — provide some additional protection from infection. Bear in mind that no amount of antibiotic ointment can compensate for inadequate wound cleaning.

Antibiotic ointments designed for wound care usually combine antibiotics effective against both gram-positive and gram-negative bacteria. The antibiotic bacitracin targets gram-positive bacteria; neomycin and polymyxin target gram-negative bacteria. Triple antibiotic ointments — brand names include Neosporin and Mycitracin — contain all three. However, some people have allergic skin reactions to neomycin, so some antibiotic ointments, such as Polysporin, contain just bacitracin and polymyxin, which provide the same coverage. Some antibiotic ointments add the topical analgesic pramocaine. Check the ingredients before you buy.

… and bandage

If you are applying a dressing with a separate bandage, try to avoid wrapping the bandage or adhesive tape completely around a limb. It can obstruct circulation, like a tourniquet, as the limb swells. If you must wrap a limb, monitor the distal pulses and check frequently for bluish color, tingling, or loss of sensation.

Movement may cause bleeding to recur, so severely injured limbs should be immobilized before evacuation. Elevation of an infected wound can reduce swelling and pain.

Step 5. Watch the wound. The fifth step in wound care is to change the dressing periodically and examine the wound carefully.

Be alert for signs of infection.

Infected wounds should be drained and washed, as described above, two or three times a day.

Infected wounds benefit from warm compresses for 15 to 20 minutes several times a day. The warmth causes the blood vessels to dilate, increases blood flow to the area, helps the body fight the infection, and loosens clots, scabs, dried serum, and pus. For an injury to a finger or toe, it is possible to immerse the wound in warm, sterile water to which an antiseptic such as povidone iodine has been added. You can make a hot compress by bringing a piece of cloth to a boil in water to make it hot and sterile, then wringing it out, folding it, and placing it against the wound.

Step 6. Consider evacuation. Once you have done everything you can to clean and protect the wound, the sixth step in wound care is to consider whether the wound is beyond your skill and requires evacuation to definitive care. Seriously consider evacuation in cases of

Severe animal bites, especially from potentially rabid animals

Deep puncture wounds, dirty wounds with embedded foreign material, and wounds that contain crushed, shredded, or ragged tissue, where there is high risk of infection

Wounds involving joints, severed tendons, or fractures

Infected wounds that do not respond promptly to treatment

Severe blood loss

Potential Infection

When you are cut, the tissue around the wound immediately constricts, compressing the small vessels and slowing blood loss. In fact, for about ten minutes, all the blood vessels in the body reflexively constrict, reducing blood flow even more. Platelets in the blood are attracted to the site of injury and form plugs in the torn vessels. Tissue clotting factors activate the clotting cascade; within minutes, clots of elastic protein fibers fill the wound. This is why, with the aid of direct pressure and elevation, almost all bleeding, even from serious wounds, will stop within ten to fifteen minutes. Over several days, the clot surface dries, forming a natural bandage in the form of a scab.

Underneath the clot, the process of inflammation also forms a protective barrier. After about ten to fifteen minutes, as the clotting process blocks the bleeding from the injured vessels, the body releases vasoactive amines into the wound region, and these cause the uninjured capillaries to get larger and start to leak, so that blood plasma pours into the wound area. In addition, mast cells under the skin release histamine, which attracts white blood cells out of the blood vessels into the extracellular fluid, where they help to clean the wound. Polymorphonuclear granulocytes swallow and kill bacteria; macrophages consume and destroy other debris left lying around.

Inflammation

These processes explain the classical characteristics of acute inflammation, listed mnemonically as four Latin words – rubor, calor, tumor, and dolor. Rubor or redness is due to the dilation of the blood vessels and the escape of red blood cells into the wound area. Calor or heat is also due to vascular dilation and increased local tissue metabolism. Tumor or swelling is caused by the leaking of fluid into the surrounding tissues. Dolor or pain is due to increased tissue tension from fluid accumulation. Some amount of redness, warmth, swelling, and pain are thus part of the normal inflammatory healing process. In addition, a slight temperature elevation is normal for a few days after a severe injury, and lymph nodes in the area of the wound may become mildly enlarged as they help trap bacteria and debris. Again, these signs are normal.

But if the inflammatory process is being overwhelmed by invading bacteria, the body responds by increasing the local inflammation. It is thus excessive inflammation which, among other things, serves as a sign of a local infection.

Infection

• Pain from a wound should normally subside by the second or third day. There may be an infection if pain persists, or especially if the pain increases rather than subsides.
• Redness is usually limited to the margins of a wound, usually within a quarter inch. There may be an infection if the redness extends beyond the margins of the wound. In particular, a clear sign of infection is the presence of red streaks extending from the wound along a limb toward the body.
• Severe swelling may be a sign of infection, especially if the skin temperature increases rather than decreases over time. Increasing limitations of motion, due to swelling and pain, may also indicate an advancing infection.
• Pus is fluid filled with dead white cells. The presence of pus in a wound indicates a failure of cellular defense and confirms the presence of an infection. The pus may be whitish, green, or even reddish, depending on the infecting organism. Sometimes, but not always, there may be a foul odor.

Septicemia

It is possible for an infection to spread beyond the local area and enter the general blood circulation. This is septicemia, sometimes called blood poisoning. Signs of developing systemic infection include lymphangitis, or enlarged and painful lymph nodes, especially if they are beyond the immediate area of the infection; a high and persistent temperature elevation; chills, headaches, nausea, vomiting, or malaise. A person with a systemic infection is desperately ill and requires immediate evacuation to a facility where definitive care — including intravenous antibiotics — is available.

In any injury, but especially in a wound to the foot, there is particular concern for tetanus, which is caused by Clostridium tetani, an obligate anaerobe that is especially common in soil contaminated with animal feces. All open wounds are susceptible, especially those that have been contaminated with soil. Tetanus is 100 percent fatal, and 100 percent preventable. In my opinion, wilderness leaders and jungle guides should require that all trip participants have up-to-date tetanus booster immunization. A booster shot received shortly after injury may prevent development of the disease.

Gangrene

Gas gangrene results from contamination of a wound by the bacterium Clostridium perfringens, widely found in soil and in the intestinal tracts of humans and animals. The bacteria grow and create spores in dead tissue where the oxygen content is very low. This is why the proper debridement of dead tissue from a wound is extremely important, especially in a wilderness setting. The signs of gangrene include gas bubbles in the wound, drainage of foul-smelling reddish-gray fluid, and crepitus or a “Rice Krispies” feeling in the skin surrounding the wound. The gas bubbles come from the bacteria fermenting carbohydrates into carbon dioxide and hydrogen. Gas bubbles under the skin cause the crepitus. Gangrene is an immediately life-threatening condition, which may be fatal in as little as thirty hours. Immediate evacuation is required.

In the next installment, we will discuss how to prevent and handle infected wounds in the jungle.

Heat illness or hyperthermia is what happens when you are too hot. There are two serious types of hyperthermia — heat exhaustion and heat stroke. The two conditions are points on a continuum which runs from being uncomfortably hot to being deathly ill. The primary difference between heat exhaustion and heat stroke is that in heat exhaustion the body’s heat dissipating mechanism has been overworked, while in heat stroke the body’s heat dissipating mechanism has been overwhelmed.

It is important to remember that, in the jungle setting, both heat exhaustion and heat stroke can often be prevented simply by adequate hydration. Whoever designed the human body made two major mistakes — the knee, which comes apart under even moderate lateral pressure, and the thirst mechanism. The trigger for thirst is a beginning electrolyte balance; that is, when you get thirsty, it is already too late. That is why it is important to drink lots of water in the jungle, and to drink it before you get thirsty. Pound it down. Force yourself. Drop a tea bag in your water bottle to give the water some taste. Set up a rule that if one person drinks, everyone has to drink.

How much should you be drinking? Under normal circumstances, water intake should be between 9 and 12 cups per day — that is, between about 2¼ and 3 quarts of water per day. The amount needed can increase with exercise and environmental factors. In 2003, the International Marathon Medical Directors Association and USA Track and Field jointly issued fluid replacement guidelines for marathon runners, advising them to drink as much as they wanted between 400 and 800 mL/hour — that is, between 0.42 and 0.84 quarts each hour. For an average amateur marathoner, that means between about two and four quarts during a five-hour marathon. Conversely, with only light to moderate exercise, a person in the desert should drink about four quarts of water per day.

But you don’t have to measure your intake when you can observe your output. You can know you are properly hydrated by paying attention to your urine. Your urine should be clear, copious, and colorless — or at least pale yellow. Most people live in a state of chronic dehydration; so, when you are properly hydrated, you should feel like you are urinating a lot.

Heat exhaustion

Heat exhaustion is actually an early stage of hypovolemic shock. The body’s fluid levels have dropped sufficiently that organs are not getting enough oxygen carried to them by the blood. The fluid pressure has dropped because of a combination of excessive sweating, dilation of surface blood vessels, and inadequate water intake.

Since the brain is one of the first organs affected by inadequate perfusion, one of the first signs of heat exhaustion is often a change in level of consciousness — spaciness, forgetfulness, confusion, odd speech, restlessness, anxiety, and changes in behavior, sometimes subtle. Other signs and symptoms are thirst, weakness, headache, nausea, dizziness, rapid pulse, rapid breathing, exhaustion, and profuse sweating. Patients can sweat so much that they feel cold, have goose bumps, and complain of chills. The skin is cool and pale.

The treatment for heat exhaustion is simple. Get the patient cool. Move the patient to the shade of a tree, fan her, pour water on her head. Remove excess clothing. Have the patient lie down. If the patient is alert and able to swallow, give water; or, if you have it, Gatorade diluted three to four times; or about a half–teaspoon of salt dissolved in a quart of water, maybe with a pinch or two of sugar. Have the patient drink as much as a quart of water over the next hour. Recovery should be rapid and without consequences. If the patient does not improve promptly, then the condition may in fact be an early stage of heat stroke, and immediate evacuation should be seriously considered.

Always suspect heat exhaustion when a person becomes ill in hot conditions, especially during physical exertion, and particularly if accompanied by changes in level of consciousness. Heat exhaustion should be treated aggressively. More important, it should be prevented by drinking lots of water.

Minnesota Vikings right tackle Korey Stringer died from heat stroke in 2001

Heat stroke, as opposed to heat exhaustion, is a life-threatening illness that requires immediate evacuation. It has many of the same signs and symptoms as heat exhaustion, but they are more severe. There is an altered level of consciousness, rapid heart rate, and increased respiratory rate. The altered level of consciousness can be dramatic — disorientation, irritability, combativeness, delusions, incoherent speech. There can even be loss of coordination and convulsions. The patient may or may not be sweating, but will complain of being hot rather than cold. The skin is hot, red, and wet rather than pale and cool. The body’s core temperature has risen to above 105 degrees. It will be obvious that something is very wrong.

The treatment for heat stroke is the same as the treatment for heat exhaustion. Cool the patient off as rapidly as possible. Remove excess clothing. Cover the patient with wet cotton clothing and fan vigorously. Apply ice if it is available, and at least pour the coldest available water over her. Concentrate on cooling the head and neck. It is probably not a good idea to try to immerse the patient in a river or stream, because a disoriented, combative, or convulsing patient is hard to manage and may drown. Do not delay. Be aggressive. You are saving a life. As the core temperature continues to rise, vital organs, such as the brain and kidneys, start to shut down. Cardiovascular and neurologic collapse are imminent. Evacuate immediately to where definitive care, including IV saline, is available, and continue cooling procedures during evacuation.

A few other points. Keep good records of vital signs, especially body temperature. The temperature may go down during cooling, and then rise again when you have stopped active cooling measures. If the patient becomes unresponsive, pay particular attention to keeping an open airway. If shock occurs, elevate the patient’s legs twelve inches.

Bear in mind that I am talking about wilderness emergency care, or care where resources are extremely limited — no ice, no normal saline, no IV start kit, no ambulance, no hospital. I will defer to others about urban street medicine, or patient management where such resources are readily available.

Coral snakes have very short fangs in the front of a small mouth. The small mouth and fangs make it hard for a coral snake to bite anything other than a finger, toe, or fold of skin. Pit vipers strike and release, but coral snakes hang on and chew. And while Crotalid venom causes rapid tissue necrosis, Elapid venom slowly attacks the central nervous system. These differences mean that you treat a coral snake bite differently than you would a pit viper bite. In particular, for Elapid envenomation,

• the use of a Sawyer Extractor appears to be of little benefit, and
• the use of the Australian pressure-immobilization technique has become accepted as a standard treatment. Since Elapid venom is a systemic neurotoxin, wrapping the entire bitten extremity can help delay systemic absorption of the venom, but, unlike Crotalid venom, will not cause local tissue necrosis.

When an envenomation occurs, the bitten extremity starts to become weak and numb after about an hour. In the following hours, the signs and symptoms of central nervous system poisoning begin to appear — nausea, vomiting, weakness, muscle twitching, tingling in the extremities, slurred speech, increased salivation, and difficulty swallowing and breathing. In the worst case, depression of the central nervous system can lead to respiratory and cardiac paralysis and death.

Elapid bite

A significant problem is that it is often hard to know whether the person bitten has been envenomated or not. The fang marks can be hard to see, although sometimes you can squeeze blood from the tiny puncture sites. Local swelling is usually minimal. There are often many nonvenomous mimics of coral snakes in the same area, so it can be difficult to know whether the biting snake was venomous or not. It can take more than an hour for the bitten extremity to feel weak or numb, and sometimes as long as twelve hours before the victim feels sick enough to need help.

So, if someone has been bitten by something that may have been a coral snake, it is important to begin treatment and observation right away, and to give serious consideration to evacuation, even in the absence of signs and symptoms, and even if you might feel foolish later if nothing happens. Treatment for Elapid envenomation in the wilderness is as follows:

• Keep the patient calm and with as little movement as possible. Provide lots of support and encouragement.
• Clean and flush the wound with clean water and apply a sterile dressing.

Wrapping the limb for an Elapid bite

• Wrap the bitten limb with an elastic bandage, at about the same tension as would be used on a sprained ankle. Start wrapping about four inches above the bite and wrap away from the body toward the hand or foot. If you have an additional elastic bandage, you can then wrap in the other direction, starting about four inches below the bite and wrapping toward the body. This should help to immobilize the venom. The wrapping should be loose enough so that you can slip a finger underneath, and you should check the peripheral pulses to make sure there is no constriction of blood flow. Remember that the venom spreads through the lymphatic system, which lies close to the surface of the skin, so that great pressure is not necessary in order to constrict its flow.
• Splint the limb and keep it at about heart level.
• Encourage the patient to drink frequent small amounts of water.
• Provide basic life support and treat for shock as necessary.
• Transport as quickly as possible to definitive medical care, where antivenom and appropriate facilities for its administration may be available.

As with Crotalid bites, the use of alcohol, incisions, electric shock, sucking, and ice are not recommended.

I have written here about the varieties and habits of snakes in the Upper Amazon and how snakebite is treated by local healers. Remember, of course, that your chance of being bitten by a venomous snake in the Amazon is really very small, especially if you take basic precautions, such as not sticking your hand blindly into places where a snake might be sleeping. It is probably worth noting that more than fifty percent of pit viper envenomations in North America are associated with alcohol ingestion on the part of the victim.

There are, as I said, two families of venomous snakes in the Upper Amazon — the Crotalidae or pit vipers and the Elapidae or coral snakes. If you are bitten by a pit viper — and actually envenomated — you are in for a memorably unpleasant experience. But, if you treat the wound properly and avoid infection, you are unlikely to die or have permanent injuries.

There is no question that a Crotalid envenomation is a medical emergency requiring urgent evacuation, if at all possible, to a definitive care facility that is equipped to administer Crotalid antivenom. In an ideal world, anyone envenomated by a pit viper in the wilderness would be immediately evacuated and receive antivenom within four hours — six at the most — in a hospital setting, under sterile conditions, with constant monitoring, and with a crash cart available in case of an allergic reaction. If such an evacuation is possible, then by all means it should be done. As professional handlers of venomous snakes say, “The best equipment for treating a venomous snakebite is a set of car keys.”

However, the first step in treatment is to avoid panic. Death is rare. Even without evacuation, most cases result in several days of serious misery and then full recovery. Remember that the fatality rate even for untreated pit viper bites is extremely low. The treatment steps are:

• Use the Sawyer Extractor. If you are in snake country, the Extractor should always be within easy reach in your pack. The Extractor can remove as much as 30 percent of Crotalid venom proteins if applied within three minutes. Use the Extractor as quickly as possible and then keep it on the bite for about thirty minutes. Because of the great suction it creates, no cutting is necessary. This should always be the first thing you do, even when evacuation is in progress.
• Remove rings, bracelets, or any other constricting jewelry on the affected limb, which may swell to as much as twice its normal size.
• Immobilize the bitten extremity with a splint, just as you would a fracture.
• Have the patient rest and keep activity to a minimum.
• Have the patient drink as much fluid as possible, in frequent small amounts, in order to maintain fluid volume and kidney flow.
• Remember that a snakebite is a contaminated puncture wound, and treat it as such.
• Get to definitive care as quickly as you can. Otherwise, have the patient rest and drink fluids; keep the wound clean; give lots of encouragement and support.

The following are not recommended for pit viper envenomations:

• Do not make incisions or try to suck out the venom. In jungle conditions, cutting into an already compromised limb is asking for an infection. You absolutely do not want pit viper venom in your mouth. Conversely, your mouth is full of all kinds of bacteria. And you can’t suck as hard as the Extractor can anyway.
• Do not use a tourniquet. Tourniquets can result in loss of the limb due to decreased blood flow. In addition, you are just keeping the venom localized where it does the most tissue damage.
• Do not use electric shock. It can be dangerous, and has no proven value in managing pit viper bites. It is the great urban legend of wilderness first aid.
• Do not use ice. There is no evidence that snake venom enzyme activity diminishes with cold. Freezing already compromised tissue can lead to frostbite, which can damage the limb more than the original bite. Packing in ice has probably resulted in more lost limbs than snakebite itself; this is particularly tragic when limbs have been lost to frostbite because of a non-envenomated bite.
• Do not give alcohol. It causes vessels to dilate and may speed venom absorption.

The use of an elastic bandage pressure wrap — recommended for use with bites from Elapidae or coral snakes — has been recommended for use in some cases of Crotalid envenomation as well. The argument against its use is that the pressure may actually increase the risk of disfiguring local tissue damage, which may then require skin grafts and extensive repair and treatment; and that removal of the pressure may result in sudden massive swelling and discoloration. The argument in favor of its use is that the spread of venom to vital organs can be life-threatening — in fact, some Crotalid bites can cause serious damage to limbs even when the bites were to a finger or foot — and the use of a pressure bandage can prevent this spread, even at the risk of greater localized damage. The way to apply a pressure bandage is described here.

The problem is that there is no way of knowing how serious the envenomation is at the outset, when the decision must be made. There is a tradeoff between averting more serious life-threatening damage and increasing the risk of painful and disfiguring local damage. Such a decision should be considered a serious one, to be decided in full consultation with the patient.

Even when you get water through a pipe, the quality of the water depends on where the water comes from and whether the pipe has any cracks or leaks. In addition, the single most important cause of gastrointestinal illness in the wilderness is oral-fecal contamination from dirty hands. Sure, you wash your hands after using the latrine, but does everyone who handles your food and water?

So, if you are thinking of heading into the jungle, here are some survival tips.

There are three sorts of waterborne microorganisms that can cause human illness in the wilderness — viruses, bacteria, and protozoan cysts. Bacteria in contaminated water may include Escherichia coli, Shigella, and even Salmonella; protozoa may include Giardia and Cryptosporidium — all potential contaminants whenever animal or human fecal material gets into your water source. It is worth bearing in mind that just about any gastrointestinal infection you get from contaminated water can do more than just spoil your trip.

Apart from packing in your own bottled water, there are four ways of treating water in the jungle.

Boiling is completely effective against protozoan cysts, nontoxic bacteria, and viruses. Bringing the water to a rolling boil is enough, except at higher altitudes, where longer boiling is required because the water boils at a lower temperature. If you are backpacking, there is nothing extra to carry, since you have a pot and stove anyway. On the other hand, boiling takes time and uses up your fuel. Boiling also does not remove sediment, but filtering the water through a bandana usually takes care of that.

Halogens such as iodine or chlorine kill bacteria and viruses, but may not kill all protozoan cysts. Iodine tablets such as Potable Aqua and saturated iodine solutions such as Polar Pure are readily available, inexpensive, and lightweight. You can make your own water treatment kit by putting iodine crystals in the bottom of a small bottle, filling it with water, and using capfuls of the resulting saturated iodine solution to treat your drinking water. If you just keep refilling the bottle with water, the iodine will last indefinitely.

Some people dislike the iodine taste of treated water, but the taste can be eliminated by adding some vitamin C, as in powdered fruit drinks; in fact, the Potable Aqua “taste neutralizer tablets” are simply ascorbic acid. Another drawback is that the halogen must be given time to work before you can drink the water — anywhere from fifteen minutes to an hour, depending on how cloudy or cold the water is. Pregnant women and people with thyroid conditions may have adverse reactions to iodine.

Mechanical filtration forces the water through a finely porous internal element inside the case in order to physically strain out solid materials, including fine sediment and most — but not all — microorganisms. Bear in mind the difference between a filter and a purifier. A filter mechanically removes protozoa and bacteria from contaminated water. A purifier goes a step further and eliminates viruses as well, by passing the water through either a matrix containing iodine, which kills them, or a filter medium that carries an electrostatic charge, which traps them. A device must inactivate 99.99 percent of viruses to be labeled as a purifier.

There is spirited debate about the relative merits of filters and purifiers. Portable filters and purifiers are compact, relatively speedy, efficient, and you can drink the water immediately. On the other hand, they are heavy, a chore to operate, occasionally cranky, and easily become clogged with sediment.

Ultraviolet light, if strong enough and applied long enough, destroys the DNA of microorganisms, making them unable to reproduce and cause illness. A small portable ultraviolet light source, weighing less than four ounces, called the SteriPEN Adventurer is designed to be inserted into a wide-mouth water bottle, and is supposed to take about fifty seconds to purify sixteen fluid ounces and about ninety seconds for a liter. It is said to be effective against viruses, bacteria, and protozoa, and it leaves no iodine taste.

A drawback is that the device is operated by batteries, and batteries require recharging or replacement, which may not be feasible in wilderness conditions; and the device’s performance is significantly affected by the quality of the batteries used. You can get the device with a solar panel battery charger storage case, but it can take two to five days to recharge two cr123 batteries, depending on sun conditions. The device does not remove sediment, but, as with boiling, you can prefilter with a bandana.

As famed Amazon explorer Colonel Percy Harrison Fawcett said, before his final expedition, “We will have to achieve a nervous and mental resistance, as well as physical, as men under these conditions are often broken by their minds succumbing before their bodies.” The term men presumably did not apply to those indigenous people who actually lived under the conditions he was describing.

There can be little doubt that this mythology is founded on a hierarchic colonial discourse, in which the colonial Other was seen — often contradictorily and inconsistently — as lazy, aggressive, violent, sexually promiscuous, bestial, primitive, innocent, and irrational, and the colonizers feared contamination by absorption into indigenous life and customs. But more, this colonial discourse was permeated by sexuality. Going native meant, above all, transgressive, interracial sex, with its attendant deterioration and degeneracy — the “abominable practices,” the “monstrous passions” of Kurtz in Joseph Conrad’s Heart of Darkness.

The promotional material for a recent book on Amazon exploration speaks of a history in which countless explorers, irresistibly drawn into the green hell of the jungle, “have perished, been captured by tribes, or gone mad.” Note the mythic conflation of death, madness, and assimilation into the indigenous. All three fates are essentially the same.

Klaus Kinski

In Aguirre The Wrath of God, directed by Werner Herzog, Klaus Kinski plays conquistador Gonzalo Pizarro on a doomed quest for El Dorado, the city of gold, in the impenetrable jungles of Peru. The story is based on a historical expedition in 1650, as recorded in the journals of a priest who accompanied the mission. The conquistadors, greedy and cruel, face an environment whose cruelty is equal to their own — hostile natives, disease, starvation, and treacherous waters.

The opening shot shows a long line of men and animals snaking their way down a trail on the eastern slope of the Andes into the jungle; the final shot — one of the most unforgettable in cinema – has the camera swooping around the insane Aguirre drifting down the river on a raft filled with corpses and monkeys. In the beginning, Aguirre is rational and careful, surrounded by all the useless trappings of triumphal European civilization, carried on the backs of native porters; in the end, firing his cannon uselessly into the jungle, he is stripped of everything but transgressive sexuality, muttering about how he will conquer Mexico, marry his own daughter, and found “the purest dynasty the earth has ever seen.”

Bulle Ogier

The Valley (Obscured by Clouds), produced and directed by Barbet Schroeder, follows a different set of European invaders — a group of hippies searching for paradise in the jungle of Papua New Guinea. The beautiful Bulle Ogier plays the bored and self-centered Vivian, married to the French Consul in Melbourne, who is in New Guinea searching for feathers of the near-extinct Bird of Paradise, which she plans to send back to Paris to sell in her boutiques. She falls in with a ragtag bunch heading for the interior to search for an unknown valley, obscured by clouds and thus invisible from the air, where the natives believe that the gods live.

What follows is not entirely clear. The feckless group heads into the jungle, Vivian has sex with the leader, they are welcomed by a primitive people wearing mud masks, they abandon their horses, and finally, at the point of death, they think they see a valley — and the movie ends.

The cruel conquistadores and the ineffectual hippies both fall prey to the madness that the jungle inflicts on Europeans. Both movies express this process in dreamy psychedelic soundtracks — by Popul Vuh in Aguirre and Pink Floyd in Valley. Both films enact the European myth of jungle madness; both sets of invaders are stripped bare, absorbed into the jungle, assimilated, finally, into primal fornication and death, gone native entirely.

It is worth taking a moment to compare the endings of the two films.

My first tambo

In fact, all ribereño houses are built on exactly the same principles — a thatched house on stilts, built entirely of jungle materials, which may range in size from a small temporary hunting shelter, just large enough to sleep one or a few people, to an elaborate structure able to house an extended family.

Some of these houses are relatively isolated; some — connected together by footpaths through the jungle, or clustered about a central square — form caseríos, villages, with a soccer field, perhaps a cement schoolhouse and community center, even a clinic or a small bodega for goods brought upriver by motorized canoe.

A ribereño house

Ribereño house construction is similar throughout the Upper Amazon. Both the thatched roof and the raised flooring are supported by upright posts made of durable hardwoods, usually huacapú (Minquartia guianensis), icoja (Unonopsis spp.), or tahuari (Tabebuia spp.). These hardwoods have acquired symbolic meaning in shamanism and plant medicine: their bark is used in medicines to enhance male potency, and is added to the ayahuasca drink to support those who drink it, just as these trees support the ayahuasca vines that climb their trunks.

The roof is thatched with irapay palm leaves (Lepidocaryum tessmannii), whose stems are looped and knotted on poles of pona wood (Socratea exorrhiza) to form long sheaves, called crisneja, that are then tied in an overlapping pattern onto the rafters with strips of atadijo bark (Trema micrantha) — the same bark that is used to bind the long cylindrical bundles of cured tobacco sold in the market. The peak of the roof is covered with yarina palm leaves (Phytelephas spp.), and the springy floor — it bounces when you walk on it, which can be disconcerting at first — is made of slats cut from the trunk of the huacrapona palm (Iriartea deltoidea). Ethnobotanist James Duke estimates that as many as twenty different species of plants may be used in the construction of a single dwelling.

Huacapú — uprights

There is usually a single primary room, where people sleep under mosquito nets, either on the floor or in hammocks; bedding and nets are rolled up during the day. There may be a separate storeroom, or a separate sleeping room for the older members of the household. Supplies and equipment are also kept up in the rafters that support the thatched roof. The kitchen is often separated from the main house, at ground level, or connected with the main house by an elevated walkway, with a thatched roof for cooking when it rains. A notched tree trunk provides steps to the main room; there may be a railing around the front of the elevated room, forming a porch, from which residents talk to passers-by.

Irapay — roof thatch

So: There is a family room, perhaps a bedroom or storage room, and a kitchen. Where’s the bathroom?

When I was living in the jungle hut of don Rómulo Magin, trying to learn the medicine, I would get up on shaky legs to vomit at the edge of the clearing. The next morning, embarrassed, I would go to look at the mess I had made, and find that everything was gone. The jungle had recycled it.

Pona — thatch crossbeams

One day, I decided to experiment. I defecated at the edge of the jungle, and waited to see what would happen. Metallic flies immediately started to swoop around my leavings, and small dung beetles converged and began eating, the females laying eggs in the warm scat. Then larger dung beetles arrived and began rolling up small balls of dung — gifts for their lady friends, who mate with the male who brings the largest present, and deposit the fertilized eggs into the ball of dung, which the couple then bury together. Other beetles burrowed under the mound to eat the smaller beetles; large centipedes came rushing up to get their share. For some reason — perhaps its high potassium or protein content — human scat is greatly prized by small jungle creatures. More than fifty species of dung beetle may converge on a human pile. Within half an hour, everything I had left on the ground was gone.

Crisneja — irapay leaves looped on a pona pole

That is one of the reasons there is no humus on the jungle floor. Humus — dirt — takes hundreds of years to accumulate. In the jungle, everything is recycled much too quickly to form dirt. This lack of soil is why tall jungle trees fall over so frequently; you can hear the sharp cracks of falling trees while lying in your hammock. Treefall is one of the primary ways in which the jungle renews itself.

You get used to this instant recycling. One of the problems with living in the jungle for many generations is that you assume that the jungle cleans itself, which is largely true. But this attitude creates some problems. One of the problems can be found on the beautiful Pacific beaches in Lima, which, even in the fanciest neighborhoods, are covered with garbage. Another problem is potable water.

Yarina — roof peak

In the jungle there are few latrines. Many people go out into the jungle to defecate, or squat in the water at the edge of the river; many houses on stilts on the river’s edge have tiny rooms with a hole in the floor directly over the water. I have seen people bathe and wash dishes downstream from where they defecate. Even when ventilated concrete latrines have been constructed, they are often not well maintained and, when full, abandoned. Many larger river boats have a small screened room sticking out over the water with a hole in the floor. Clean drinkable water remains a significant need in many ribereño communities.

There is an amazing abundance and variety of fish in the Upper Amazon. For both mestizo and indigenous peoples, the lakes and rivers are an endless source of food, with more than two thousand species of freshwater fish. There are catfish of all sorts — the boquichico (Prochilodus nigricans), carachama (Pterygoplichthys multiradiatus), doncella (Pseudoplatystoma tigrinum), and especially the delicious dorado (Brachyplatystoma flavicans), which can grow to a hundred pounds in deep river channels and oxbow lakes. There are carahuasú (Astronotus ocellatus), paña, piranha (Pygocentrus nattereri), tambaqui (Colossoma macropomum), sábalo (Brycon melanopoterus), and paiche (Arapaima gigas), the largest freshwater fish in the world, whose flaky and delicately flavored flesh has been featured in Gourmet Magazine.

Paiche (Arapaima gigas)

Machiguenga greet strangers by asking, “Are there fish in the river where you live?” La Patarashca, a restaurant in Tarapoto, serves doncella stuffed with shrimp in a sauce of cocona fruit (Solanum sessiliflorum), and as a patarashca — stuffed leaves — with tomato, onion, and sweet chili, wrapped in bijao leaves (Calathea lutea). People are not fooling around here.

But first you have to catch the fish.There are a number of places in the Upper Amazon which are particularly good for finding fish. Large and medium-sized rivers in low areas often form numerous meanders which, when the river changes course, become cochas, oxbow lakes. These cochas often have sediment settled on the bottom, relatively clear water, and high temperatures, and therefore rapid plant growth, which in turn supports quite large fish populations. Sometimes too you can see strips of clear and very slow water in a river. These are quiet places where plankton tends to grow; you can usually find fish downstream. You can also find fish under camalones, places where aquatic vegetation has formed a dense mat on the surface of the water. And fish love to move into the waters covering seasonally flooded forests.

Carachama, sailfin catfish (Pterygoplichthys multiradiatus)

It is possible to take fish just with your hands. It is not as hard as it sounds; I once caught a beautiful trout with my bare hands in a stream in the Esacalante Wilderness. In the Amazon, people wade close to shore in muddy water, gently feeling for fish under rocks and in the mud. In particular, carachama, the armored sailfin catfish (Pterygoplichthys multiradiatus), constructs burrows in the muddy banks of the cochas and rivers in which it lives, each a few feet deep and generally angled downward. You only need to feel around for a burrow, reach in, and very carefully — because carachama have very sharp spines on their dorsal fins — pull a carachama out of its hole and toss it up onto the bank. They are delicious.

Net casting

People in the Amazon often fish with hook and line — an innovation dependent on the availability of steel hooks and high test monofilament fishing line. All you have to do is tie a hook to a length of line on the end of a stick, put a piece of grasshopper on the hook, and toss the hook into the water. Especially in an overpopulated cocha, in just a few minutes you have caught a fish. You can do this over and over again; in half an hour, you have caught enough fish for several days. You can be creative, and tie a piece of wood to the string as a float. If you have a family to feed, you can set out a trotline with baited hooks. Hook-and-line fishing can be done where other methods do not work — at night; during the rainy season, when the water is turbid; in the main current of the river. And it is considered to be — heck, it is — fun.

Communal fishing with barbasco (Lonchocarpus urucu)

Fishing nets can be cast from a canoe or by wading out into the water. Casting a fishnet requires skill clearly beyond my own, although, to my chagrin, I have seen numerous young boys do it quite successfully.People also fish using fish spears or bows and arrows — usually with barbed two-tined heads — either from a canoe or from shore, sometimes on the river right in frront of the village. Spear and bow-and-arrow fishing is largely limited to the dry season, when rivers tend to be clear rather than silty. A fisher can also put a tabaje, a fish trap, across a cocha outflow. Tabajes are woven from strips of caña brava, giant cane (Gynerium sagittatum) or bombonaje (Carludovica palmata). I have seen two mestizo fishermen work a running stream by anchoring a woven barricade with sticks downstream, driving fish into the trap from upstream, and then gathering them by hand. In a few hours they had caught enough fish, after being dried and salted, to last for a week.

Preparing fish for salting and drying

Fish poison is also widely used in the Upper Amazon. The term barbasco can be used to refer to fish poison in general, or more specifically to Lonchocarpus urucu, which is of sufficient importance that some indigenous peoples cultivate it in their gardens. The procedure is simple: the root is is dug up, carried to the fishing place, and pounded with sticks so that the milky sap can be drained into the water. The primary active ingredients are rotenone and deguelin, which affect gill function in fish, inhibiting their ability to breathe. Within fifteen minutes or so fish begin to float on the surface of the water, where they can be collected by hand or in baskets, hit on the head with a machete, speared, or shot with a bow and arrow.Fishing with barbasco in a cocha is simple; squeeze the milky sap into the still water, watch it spread, and then collect the fish. It only takes one or two people to fish a cocha in this way. On the other hand, in a flowing stream or river, you have to build a dam at the upper end of the fishing area to slow the flow, and another at the lower end — sometimes with a woven basketry net — to make it easier to capture the stunned fish. Such temporary dam construction may require additional people, which can, of course, turn into a party.

Fer-de-lance (Bothrops atrox)

n the Amazon, the pit vipers of most concern are the thirty-one species of snake somewhat indiscriminately referred to by the name fer-de-lance or lancehead, all in the genus Bothrops, and all looking very similar, with long bodies and large triangular heads. The lanceheads live in the lowland jungle and average four to six feet in length, although they may grow as long as eight feet. They are generally tan with dark brown diamond-like markings along their sides, and are very well camouflaged. Amazonian pit vipers — as opposed to the colorful coral snakes — have clearly chosen crypsis over warning; it is easy to pass very close to a fer-de-lance without noticing it. Species of Bothrops apparently account for most of the serious snakebites in South America.

Bothriopsis bilineatus

Mestizos in the Upper Amazon generally refer to the various Bothrops species as jergón in Quechua or as vibora in Spanish. The Spanish term cascabel, rattle, usually refers to the genus Crotalus, the rattlesnake, which is not found in neotropical environments, but rather in dry habitats such as the savannahs in Guyana. In the Upper Amazon, the term cascabel may be used to refer to juveniles of the genus Bothrops.

There are also two species of so-called forest pit vipers, in the genus Bothriopsis — the two-striped and the speckled, both exclusively arboreal and camouflaged for tree dwelling, with the color green in their pattern. These forest pit vipers are slender snakes, reaching five feet in length, with prehensile tails, usually found coiled around twigs and bushes.

Bushmaster (Lachesis muta)

Finally, the Amazonian bushmaster or Lachesis muta — the Latin name means silent fate — is the largest pit viper in the world, reaching lengths up to twelve feet. Usually called by the Quechua term shushupi, the bushmaster is found in the lowland rainforest throughout the Amazon. It is generally a coppery tan with dark brown diamond-shaped marks on its back, rather than on its side. It is active at twilight and night, and coils up in the buttresses of large trees, or under roots and logs. After having fed, a bushmaster will remain in place until it has digested its prey, a period of two to four weeks.

Whereas the other neotropical pit vipers bear live young, the bushmaster lays eggs. Because of its length, it can strike over a long distance; because of its large fangs, it can deliver a large dose of venom — probably the largest venom dose of any pit viper. However, bushmasters are very reclusive and therefore rarely encountered; many experienced tropical herpetologists have yet to see their first wild specimen. Thus, few envenomations actually occur, although the fatality rate is reportedly high. I have been unable to find information about the age, physical condition, or treatment of reported fatalities. And it is worth adding that envenomation by any of the Elapidae in the Amazon — primarily fifty-three species of coral snakes in the genus Micruris — is apparently very rare as well.

Crotalid envenomation

Pit viper venom is a complex mixture of enzymes, which varies from species to species, and which is designed to immobilize, kill, and digest the snake’s prey. Thus, pit vipers strike and release quickly; coral snakes, on the other hand, have neurotoxic venom, and small mouths and short fangs, so that they tend instead to hang on and chew. Crotalid venom works by destroying tissue, and is capable of causing significant, sometimes disfiguring local tissue damage; but deaths — at least in the United States, where records are available — are very rare and limited almost entirely to children and the elderly.

Indeed, many pit viper strikes in fact are dry and inject no venom, even when there are fang marks. The snake may have recently injected venom and not yet replenished; it may be because humans are much bigger and give off a lot more heat than the snake’s usual prey, and this throws off the timing of the venom delivery. Additionally, Crotalids can differ significantly in the toxicity of their venom, even within a single litter.

Cocona (Solanum sessiliflorum)

And pit vipers really want nothing to do with humans. Humans are too big to eat, put out a confusing amount of heat, and are potentially dangerous. As a general rule, you will be bitten only if the snake perceives you as an immediate threat. Snakes hate surprises. That is why pit viper strikes on humans are overwhelmingly on the extremities. In North America, most rattlesnake envenomations are associated with alcohol ingestion on the part of the victim. Rock climbers are at risk for rattlesnake bites because they blindly reach overhead to grab a ledge on which a rattlesnake is sitting in the sun.

Pit viper envenomation can be excruciatingly painful — one expert has said that, on a pain scale of one to ten, rattlesnake bites are an eleven — and the discomfort can last for several days. The envenomated extremity can also become frighteningly ugly, leading to panic in both the patient and the caregiver. Greater or smaller areas of the extremity can turn blue or black, swell alarmingly, and develop large blood blisters. It is altogether an unpleasant experience. There is no question that a Crotalid envenomation is a medical emergency requiring urgent evacuation if possible. However, the first step in treatment is to avoid panic; even without evacuation, most cases result in several days of serious misery and then recovery. More rarely, skin grafts may be necessary. Remember that the fatality rate even for untreated pit viper bites is extremely low.

Ishanga blanca, white nettle (Laportea aestuans)

Mestizos and indigenous peoples in the Upper Amazon use a wide variety of plants to treat snakebite. Ethnobotanists James Duke and Rodolfo Vasquez list twelve genera used for that purpose; Richard Evans Schultes and Robert Raffauf list twenty-nine. My teacher don Roberto Acho Jurama often applies a patarashca, poultice, made of a banana leaf, wrapped around the site of envenomation, filled with the finely chopped tuber of jergón sacha (Dracontium loretense), changed every few hours; he also uses ishanga blanca, white nettle (Laportea aestuans), and cocona (Solanum sessiliflorum), as well as chewed leaves of mapacho, tobacco (Nicotiana rustica), applied directly to the wound. The patient may be given a cold-water infusion of jergón sacha to drink, or cocona fruit boiled with sugar.

Shamans all have their own songs to drive out venom and heal snakebite, usually called, generically, icaro de vibora, pit viper song; remember that icaros generally do not have individual titles in the way that, say, songs do in North America. This icaro is then combined with the definitional triad of mestizo shamanic healing — shacapar, rattling; chupar, sucking; and soplar, blowing tobacco smoke — followed by application of the herbal remedy.

It is hard to judge the effectiveness of any of these remedies. There are few records; there is little long-term follow-up; Crotalid envenomation is frequently self-limiting. There appears to be little empirical basis for allegedly high mortality rates in cases of bushmaster envenomation; a pit viper strike can create a deep puncture wound and severely compromised tissue, so sepsis, especially in the jungle environment, must be a frequent complication. There is evidence that a number of plants traditionally used to treat snakebite — especially those in the family Urticaceae, such as ishanga blanca — have antiinflammatory, immunomodulatory, and thus potentially antivenom activity, which remains to be investigated.