Bed Bugs

The common bed bug, Cimex lectularius, is a small, oval, wingless, reddish-brown insect that requires blood meals from humans, other mammals, or birds to survive. Typically, it feeds every 5 to 10 days but can survive for a year or more without feeding. After feeding, its color changes from brown to purplish-red and it will appear larger and more cigar-shaped. Bed bugs are normally about 5 to 9 mm (1/5-1/3 inch) in length; young bed bugs are smaller and nearly colorless, except after feeding.

Bed bug infestations are increasing in the US and internationally, probably due to an increase in international travel, changes in pest control strategies in travel lodgings, and insecticide resistance. Although bed bugs have not been shown to transmit disease, their bites can produce strong allergic reactions and emotional distress.

Prevention: Avoid or reduce exposure to bed bugs by researching before booking a hotel room; inspecting the premises for bed bugs upon arrival at the hotel; keeping suitcases closed and off the beds and floor; and after arriving home, immediately washing laundry in hot water and detergent and drying on high heat for 30 minutes.


Bees and all other insects of the order Hymenoptera (fire ants, hornets, wasps, and yellow jackets) can deliver bites and stings that are painful but rarely fatal. Humans are usually stung as a result of disturbing the insects or their nests. Insects inject venom into the skin, sometimes leaving a stinger embedded, and the venom causes pain, redness, and swelling. Remove the stinger as quickly as possible because venom can continue be injected as long as it remains. The method of removing the stinger is unimportant, speed is what counts. Travelers can choose from any number of topical products for pain relief, some made especially for insect bites and stings. If ice is available, use it to reduce swelling. Oral antihistamines such as diphenhydramine (Benadryl) or chlorpheniramine maleate (ChlorTrimeton) can alleviate swelling and itching but may cause drowsiness.

Multiple stings or hypersensitivity (allergy) to venom can cause an anaphylactic reaction within minutes in some individuals. Instead of a local response, the body's defenses overreact to the venom, causing symptoms that may include flushing, dizziness, nausea, headache, blurred vision, shortness of breath, irregular heartbeat, or fainting. If any of these symptoms occur, get medical help immediately. In the most severe reactions, throat tissue begins to swell, leading to airway obstruction and death.

People who know they have a sensitivity to bites or stings should wear a medical alert tag and carry a sting kit (epinephrine auto-injector and an oral antihistamine) at all times to decrease the allergic reaction until medical help is found. Become familiar with the use of the auto-injector before an emergency.

Prevention: Observe insect precautions and avoid disturbing insects or their nests. Wear shoes and socks in brush, grass, or forest; tuck trousers into socks when necessary. Inspect bedding carefully and shake out clothing before putting it on. Travelers should consider carrying a sting kit if they will be outdoors and away from medical help, whether or not they are prone to allergic reactions.


Fleas are tiny, wingless bugs that live wherever blood is available to feed on. Some types can jump several feet, so in addition to looking for moving dark spots on ankles and bedding, check knees and arms as well. Flea bites cause small raised red spots that itch intensely; use topical creams with hydrocortisone to control itching. Fleas can also carry diseases.

Prevention: Observe insect precautions, wear foot-enveloping shoes, and stay in clean lodgings. Vacuuming the floor, carpet, and furniture is especially helpful in getting rid of fleas, flea eggs, and larvae.


Flies can transmit parasites and spread disease among humans and animals when they bite or sting. Even more common is their role in carrying bacteria, viruses, and parasites from feces to food products.

Prevention: Observe food, beverage, and insect precautions. Avoid areas where flies congregate, such as garbage dumps and fields where manure is used as fertilizer.


Lice are small gray or brown bugs that are acquired from contact with infested persons or fabrics, live on blood and, can pass disease to humans. Head lice and crab lice (which usually reside in the pubic area) infest the roots of hair shafts, leaving tiny white eggs that are difficult to remove. They can cause itching and rash. Body lice usually live in the seams of clothing, taking frequent side trips to feed.

Prevention: Lice can be combed out of hair using soap or vinegar and a fine-toothed comb, but the most efficient method is the use of chemical dusts, lotions, or shampoos made for this purpose. Because some of the chemicals may be toxic if overused, follow directions exactly. Antihistamines can help control itching. Infested clothes, bedding, and other fabrics must be cleaned thoroughly in very hot water (use the hottest cycle on washers and dryers), treated with insecticides, or heated at 70°C (160°F) for 30 minutes.

Sand Flies

Sand flies are found mainly in tropical and subtropical climates and tend to breed in garbage and manure. Sand flies are most active between dusk and dawn and hide in dark corners during the day. The bite of the female spreads leishmaniasis and bartonellosis to humans. Sand flies are tiny, and the grid of most window screens and mosquito netting is not small enough to keep them out.

Prevention: Use a permethrin-based insecticide spray on screens and netting to kill sand flies on contact. Keep bed netting tucked in tightly around the base of the mattress at all times. Avoid disposal areas or fields where manure is being used as fertilizer. Observe insect precautions when traveling in areas where sand flies are responsible for spreading disease.


Scabies mites cause an intensely itchy, raised red rash. The mites burrow into human skin to lay their eggs and are spread among people through physical contact with skin or fabric. Because of the length of the mite life cycle, it may be 6 to 8 weeks after contact before symptoms appear. These start with small itchy bumps, followed by the rash, usually at the waist, underarms, inner thighs, and/or backs of legs. Itching may increase at night.

Prevention: Various chemical lotions and creams are made to kill mites. They are applied over the entire body, left on for several hours, and then washed off. Everyone living or traveling with a person who has been infested must also be treated, even if they do not yet show any symptoms. Antihistamines help relieve itching, which can continue for up to 2 weeks after treatment. All clothing, bedding, and other fabric should be cleaned thoroughly in very hot water (use the hottest cycle on washers and dryers), heated at 70°C (160°F) for 30 minutes, or sealed tightly in plastic bags for 3 to 5 days until the mites are dead.


Scorpions live in desert or warm tropical climates. They are most active at night; during the day, they usually hide indoors or outdoors in cool, shaded areas. They can deliver an extremely painful (sometimes fatal) sting from a barb on the tail if disturbed. Scorpion venom can cause sweating, nausea, nervousness, vision and breathing problems, muscle spasms, high blood pressure, seizures, or paralysis.

Prevention: To avoid being stung, wear shoes and socks during outdoor activities in risk areas, and shake out all clothing, shoes, and bedding before every use. Do not disturb a scorpion. In the event of a sting, apply ice, immobilize the affected area, and seek medical care immediately.


Snakes strike fear into the hearts of many people, but very few species can severely injure or kill humans. Snakes are almost always found in rural areas, and the incidence of snakebite among travelers is low. Nevertheless, travelers should be cautious if they plan on spending time in the rural outdoors.

Prevention: Ask local people if venomous snakes are in the area, exactly what they look like, and where they are found. Wear shoes and socks, stay on paths, and keep hands and feet away from crevices, cracks, tall grass, or any place that cannot be clearly seen. Snakes can sense nearby humans and will try to escape; let them. If bitten by a snake, get help immediately, even if no symptoms occur. Many bites from venomous snakes are "dry" and do not contain venom, but medical help is called for because of the potential for injury.


Spider venom can disable or kill insects. Spiders also bite people, but only about 40 of some 30,000 known species are dangerous to humans. Of these, most fatal bites are from the groups that include the brown recluse (varieties found in the Americas, the Mediterranean, North Africa, and Israel) and the black widow (varieties found in Africa, the Americas, Australia, the Mediterranean, and New Zealand). Other venomous spiders of concern include the Brazilian "banana spider" and the funnel-web spiders of Australia and Tasmania.

Travelers should seek medical help immediately if bitten or if unaware of being bitten but experiencing symptoms such as sweating, nausea, rapid heartbeat, muscle spasms, blurred vision, or breathing problems.

Prevention: Do not disturb the nooks and crannies where spiders hide. Wear shoes; wear gloves when it seems prudent and practical to do so, for instance, when gardening or digging. Shake out towels, clothing, and bedding before each use. Be especially careful in outdoor toilet facilities, which are notorious spider hideouts.


Ticks are found worldwide, often in brushy or leafy undergrowth or caves. Before feeding they can be as small and dark as a freckle; when engorged they might be the size of a button. Adult ticks have 8 legs. Their jaws are built to latch onto skin as they feed, making them difficult to remove once they are in place. Before ticks can drink blood, they have to inject saliva to thin it, and any organisms they carry can be transmitted to the host. Ticks spread diseases such as typhus, Lyme disease, and encephalitis. It takes hours for ticks to get completely anchored, so don't assume they are fully embedded upon finding one.

Prevention: Reduce the chances of tick-related illness by observing insect precautions. Perform full-body checks for ticks every day; don't forget to check the scalp, behind the ears, the back, and other hard-to-reach areas. Use a mirror or employ the buddy system with traveling companions. To remove a tick, first flick or pull gently to see if it comes off. If the tick is already embedded, pull it up from its back end and work it out firmly until the mouth parts have disengaged. Any parts left in can cause infection.


Worms and other parasites can cause multiple health problems, including intestinal and neurological ailments. Some enter the body via food or drink; others burrow through the skin of persons swimming in infected water or walking barefoot on infected ground. Almost all cases can be treated, but prevention is much preferred.

Prevention: Be aware that these creatures live in sand, soil, water, and food (especially in developing countries) and take measures to avoid them. Wear shoes and observe food, beverage, and insect precautions.