Overview of Travel Health and Safety

Additional Illnesses

The following section contains descriptions of less common travel-related illnesses. However, risk depends on one's particular destination and activities; be aware of these illnesses and know how to prevent them. As with other diseases, if symptoms appear during or after travel, seek medical attention.

African Trypanosomiasis

African trypanosomiasis, or sleeping sickness, is a parasitic infection caused by the bite of an infected tsetse fly in sub-Saharan Africa. The acute form of the disease occurs in grasslands and savanna woodlands in eastern and southeastern Africa, which are areas where tourists go on safari. Most of these cases occur in Malawi, Tanzania, Uganda, and Zambia. The chronic form of this disease occurs in central Africa and limited areas of West Africa, in wooded areas around rivers, mostly in rural areas; transmission is higher during the dry season. The acute form occurs rapidly, with symptoms beginning within days or weeks of infection and a skin lesion at the bite site in 80% of cases; neurological involvement appears within a few months. For the chronic type, the first symptom in half the cases is a lesion at the bite site occurring 1 to 2 weeks after the bite. Systemic symptoms occur weeks to months later and include intermittent high-grade fevers, enlarged lymph glands, edema, and an itchy rash. Months to years later, slowly progressive neurological symptoms occur, causing increasing sleepiness, coma, and death. The disease is rare in short-term travelers, but expatriates living or working in affected areas may be at risk. Most short-term travelers who do acquire the acute form of the disease have fevers and systemic symptoms by the end of their trip or shortly after returning home.

Prevention: Avoid proximity to animals such as those found in game parks. Wear light-colored (not blue), heavyweight clothing. Insect precautions (e.g., DEET and permethrin) are minimally effective against tsetse flies (but will protect against mosquitoes).

Anthrax

Anthrax is an infectious illness caused by spore-forming bacteria; the spores are resistant to disinfection and physical destruction. Anthrax is usually transmitted to humans through contact with diseased animals or animal products. The resulting infection can be cutaneous, causing skin lesions; inhalation, causing influenza-like symptoms and respiratory distress; or gastrointestinal, which causes severe abdominal pain and fever. Anthrax occurs globally (uncommon in most industrialized countries) but is most common in impoverished agricultural regions in sub-Saharan Africa; central and southwestern Asia; the Caribbean; Central and South America; northern, southern, and eastern Europe; and parts of the Middle East.

Prevention: Travelers are at low risk of naturally occurring disease but should avoid contact with livestock and untreated animal hides and carcasses. Avoid consumption of meat from animals of uncertain origin. Vaccine is available but generally recommended only for persons with high-risk occupations.

Bartonellosis

Bartonellosis is a bacterial infection that is transmitted to humans by the bite of infected sand flies. It can occur as an acute or chronic illness. The acute phase, Oroya fever, is characterized by fever, headache, weakness, muscle aches, and exhaustion. As the disease progresses, anemia, enlarged kidney and spleen, swollen lymph glands, and changes in mental status can occur. Seizures, pulmonary edema, and generalized connective tissue edema can also occur. Infection not treated during this phase has a high fatality rate. The chronic phase usually begins after the acute phase and is characterized by verruga peruana, which are skin lesions that can last for months or even years. Bartonellosis occurs in the South American Andes in central Peru and parts of Ecuador; altitude is also a factor, with the endemic zone ranging from 500 to 3,200 m (1,600 to 10,500 ft) above sea level.

Prevention: If traveling in a risk area, avoid exposure to sand flies and observe insect precautions during peak biting activity times; the sand flies that spread bartonellosis are active from dusk to dawn. Because sand flies are about one-third the size of mosquitoes, they can penetrate standard mosquito nets. Use permethrin spray on screens and nets. (See Sand Flies.)

Brucellosis

Brucellosis is a bacterial disease that is transmitted to humans mainly from goats, cattle, sheep, camels, yaks, and hogs. In travelers, the most common source of infection is consumption of unpasteurized dairy products, especially fresh goat cheese and other products from the aforementioned animals. It can also be transmitted by contact with infected meat or animals or inhalation of contaminated dust. The incubation period is 2 to 4 weeks. Initial symptoms include fever, malaise, muscle aches, fatigue, chills, and weight loss. Long-term complications are uncommon in travelers. The disease occurs worldwide; high-risk regions include the Arabian Gulf area, the Mediterranean basin, South and Central America, South Asia, and parts of Mexico.

Prevention: Avoid consuming unpasteurized dairy products, especially goat-milk–derived products, locally prepared ice cream, and undercooked meat or dishes containing meat tissues or bone marrow. Avoid close contact with potentially infected animals and their secretions, particularly if cuts or abrasions of the skin are not fully healed.

Chagas' Disease

Chagas' disease (American trypanosomiasis) is mainly transmitted to humans by blood-sucking insects known as reduviid bugs (kissing bugs) and uncommonly by ingestion of foods (e.g., contaminated, freshly squeezed sugar cane or acai juice) contaminated with infected bugs or their feces. If infection is acquired through a skin lesion, some persons develop a red, hardened area ("chagoma") at the site, along with enlarged lymph glands. Persons who acquire the infection through the surface of the eye or eyelid lining develop painless swelling of the eyelids and tissue around the eyes. Shortly after the initial symptoms, fever, malaise, enlarged and painful lymph glands, generalized edema (swelling), and mildly enlarged liver and spleen may appear. A few persons (20%−30%) will develop central nervous system symptoms and/or cardiac involvement, which can be fatal. Acute symptoms usually resolve within 8 to 10 weeks. The chronic phase develops years after the initial infection. The disease may be mild or severe. The severe form is marked by an enlarged heart and extensive heart damage and can be fatal. The disease occurs only in the Western Hemisphere and is endemic in Central and South America and Mexico. Risk to travelers is very low; the highest risk is for persons sleeping in mud huts in the poorest areas of endemic Central and South American countries.

Prevention: Avoid sleeping in houses that are constructed of mud, adobe, or palm thatch. If such accommodations are unavoidable, search the sleeping areas thoroughly for bugs and use bed nets. Avoid blood transfusions that have not been screened for Chagas' disease. Avoid freshly prepared fresh fruit and cane juices from unsanitary sources in endemic areas.

Ciguatera Poisoning

Ciguatera poisoning is caused by eating fish that have accumulated a high level of toxins. Especially risky are larger carnivorous fish that live near coral reefs, such as amberjack, barracuda, grouper, moray eel, mullet, parrot fish, red snapper, surgeon fish, trigger fish, and wrasse. Symptoms can include numbness or tingling of lips, tongue, mouth, throat, arms or legs; diarrhea; cramps; and vomiting; "heat and cold reversal" (a burning sensation when touching something cold and a cold sensation when touching something hot); or cardiac symptoms such as irregular heartbeat. Fatal respiratory paralysis can ensue in the most serious cases. Symptoms become more severe with each exposure to the toxin.

Prevention: The toxin is tasteless and odorless and cannot be destroyed by cooking, so exercise caution when eating fish in risk areas, particularly throughout the Caribbean, the Gulf of California, the Gulf of Mexico, South Pacific Islands, and Southeast Asia. Avoid eating the fish mentioned above, but if that is not possible, eat smaller portions or smaller, younger fish (larger fish have higher levels of toxin); do not eat the heads or internal organs of these fish (organs retain more toxins); and do not eat any fish considered dangerous by the local population.

Dysentery

Dysentery is a term for illnesses characterized by abdominal pain, bloody diarrhea, cramps, and fever. Travelers are most likely to encounter 2 types. Amoebic dysentery (amebiasis) is common in tropical climates. Symptoms include abdominal discomfort with both diarrhea and constipation. Serious cases can cause fever, chills, and frequent diarrhea containing blood or mucus. Bacillary dysentery (shigellosis) is common in regions with poor sanitation or anywhere hygienic standards are lax. Influenza-like symptoms appear suddenly, 1 to 4 days after ingestion of the bacteria, including diarrhea that can last up to a week.

Prevention: Because illness is caused by ingesting contaminated food or water, observe food and beverage precautions. (See Travelers' Diarrhea.)

Ebola Virus Disease

Ebola virus disease (EVD) is a rare, severe, often-fatal disease caused by infection with Ebola virus. Transmission occurs through direct contact with blood or bodily fluids from an infected person. The onset of illness is abrupt and is characterized by fever, headache, joint and muscle aches, sore throat, and weakness, followed by diarrhea, vomiting, and stomach pain. A rash, red eyes, hiccups, and internal and external bleeding can also occur. EVD is found in remote areas of central and western Africa.

Prevention: When traveling to these areas, avoid close physical contact with people who appear ill. Travelers should avoid bats and other rodents and should not eat unidentified or undercooked bush meat. Vaccine is available from the US CDC but is only recommended for responders to an outbreak and persons with high-risk occupations.

Filariasis

Filariasis is a systemic parasitic disease caused by microscopic worms (filariae). Larvae, which later develop into adult worms, are transmitted to humans by biting flies and mosquitoes. In the tropics and subtropics, filariae can cause 3 important diseases: lymphatic filariasis, onchocerciasis (river blindness), and loiasis.

Early symptoms of lymphatic filariasis include recurring fever, pain, and swelling of lymph nodes in the arms, legs, or scrotum. When lymph flow is obstructed, swelling of the affected body part occurs (called elephantiasis). This type of filariasis is transmitted through mosquito bites; most mosquitoes bite at night but a few bite during the day. Early symptoms of onchocerciasis include itching of the skin or eye, rash, skin nodules, and swelling of a limb. This type of filariasis is caused by the bite of the blackfly ("buffalo gnat"); they bite throughout the day, especially at dawn and dusk. (See Onchocerciasis.) Early symptoms of loiasis may be recurrent itchy or swollen skin or a worm seen migrating beneath the conjunctiva of the eye. Loiasis is spread by deer flies, mango flies, and mangrove flies, which bite throughout the day and especially around noon.

Prevention: Observe insect precautions when traveling in a risk area; a preventive drug may be used for some long-term travelers (but not short-term travelers).

Giardiasis

Giardiasis, a diarrheal illness caused by the microscopic protozoa Giardia lamblia is acquired by ingesting contaminated water or food, including swallowing contaminated recreational water, exposure to fecally contaminated environmental surfaces, and person to person by the fecal-oral route. Giardiasis occurs throughout the world, and risk is highest for persons who live in or visit rural areas, trek in backcountry areas, or frequently eat, drink, or swim in areas that have poor sanitation and inadequate drinking water treatment facilities. Symptoms often begin gradually, with loose stools occurring in distinct episodes during the day and an increase in intestinal gas and bloating; symptoms then become more bothersome and are associated with fatigue. Symptoms can persist for months.

Prevention: Observe food and beverage precautions and hand hygiene. See a health care provider about chronic diarrhea. (See Travelers' Diarrhea.)

Lassa Fever

Lassa fever is an acute, highly contagious viral infection. In many cases, few symptoms exist but severe cases can be fatal. In persons who do have symptoms, the onset of symptoms is gradual, over several days, and may include fever, general discomfort, muscle pain, dry cough, chest and abdominal pain, headache, and sore throat. As the illness progresses, symptoms include facial and neck swelling and difficulty breathing. In severe cases, confusion, shock, and seizures may occur. Lassa fever is found in tropical regions, particularly rural western Africa where infections tend to occur in clusters around rural villages; however, urban cases have occurred. Infections can occur at any time of the year, but most human cases occur during the dry season between January and May. Travelers at the highest risk are long-term visitors, expatriates who are likely to stay in substandard accommodations, and adventure travelers.

Prevention: Avoid contact with rodents (including their feces) and food or water potentially contaminated with rodent feces. Avoid staying in accommodations with known rodent infestation when traveling in areas of risk.

Leishmaniasis

Leishmaniasis is caused by parasites spread to humans by the bite of an infected sand fly. (See Sand Flies.) Several forms of the disease exist. Cutaneous leishmaniasis is characterized by skin lesions and ulcerations that develop several weeks after being bitten. If untreated, the sores last from weeks to years. In some cases, cutaneous lesions may seem to heal, but the parasites then invade the soft tissue of the face, causing inflammation and destruction of nose and mouth tissue resulting in mucosal leishmaniasis. Visceral leishmaniasis, also called kala-azar, is rare in travelers; no symptoms may be present or may include a slowly progressive febrile disease with abdominal enlargement, weakness, weight loss, dry scaly skin, edema, hemorrhage, and potentially death if not treated. Leishmaniasis occurs in parts of Africa, the Americas, Asia, Europe, the Indian subcontinent, and the Middle East.

Prevention: If traveling in a risk area, avoid exposure to sand flies and observe insect precautions during peak biting activity times; the sand flies that spread leishmaniasis are generally night biters, with activity between dusk and dawn. Because sand flies are about one-third the size of mosquitoes, they can penetrate standard bet nets. Use permethrin spray on screens and nets. Consult a health care provider about any incidence of prolonged fever, anemia, weight loss, or unhealed lesions.

Leptospirosis

Leptospirosis occurs worldwide, with a higher incidence in tropical climates; most cases occur during or soon after rainy seasons. A variety of animals (e.g., rodents, dogs, livestock) carry Leptospira bacteria in their urine, which can infect water where people swim or bathe. The disease is transmitted to humans through direct contact with contaminated water, soil, or animal urine through contact with open skin or mucous membranes of the eyes, nose, or mouth. Most cases occur 5 to 14 days after exposure. The disease begins with chills, fever, headache, and muscular pain. Weil's disease, the most serious form of the infection, is identified by jaundice (yellow skin and eyes), hemorrhage or bleeding in the skin and subcutaneous tissue, shock, and cardiac arrhythmias. Death can occur. Adventure travelers and persons who engage in hiking, biking, camping, swimming, boating, or other water sports in natural freshwater bodies are at risk for acquiring leptospirosis.

Prevention: Avoid exposure to potentially contaminated water, soil, and mud. Do not swim or wade in fresh water that might be contaminated with animal urine. Wear protective clothing or footwear during recreational activities that might involve exposure to contaminated water or soil. Travelers should also be aware of the dangers of urine contamination when befriending a stray animal and should carefully wash or avoid fresh vegetables grown in soil with suspected contamination and observe hand hygiene. Some adventure travelers take doxycycline (200 mg/week) to prevent infection. Ask a health care provider if this antibiotic is indicated.

Onchocerciasis

Onchocerciasis, sometimes called river blindness, is a disease of the skin and eyes caused by the filarial nematode (roundworm) Onchocerca volvulus. Humans contract the disease when bitten by infected blackflies ("buffalo gnats"), which are found near rapidly flowing rivers and streams. The fly deposits the infective larvae beneath the skin of humans, which penetrate the human tissue and develop into adult worms after about 1 year. Early symptoms include itching of the skin or eye, rash, skin nodules, and swelling of a limb. In heavy infections, the larvae may invade the eyes and cause blindness. Onchocerciasis is widespread in river basins and forests of tropical sub-Saharan Africa and Sudan, as well as in valleys of east-central Africa and Yemen. Travelers can get this disease, especially if they live in endemic areas and work outdoors.

Prevention: If traveling in a risk area, avoid breeding locations of the black fly and observe insect precautions, including the wear of protective clothing (long-sleeved shirts and long pants), during peak biting activity times; the black flies that spread onchocerciasis can bite throughout the day but have peak activity at dawn and dusk.

Rocky Mountain Spotted Fever

Rocky Mountain spotted fever, caused by the bacterium Rickettsia rickettsii, is spread to humans by ticks. Fever, headache, and muscle pain occur 2 to 14 days after being bitten by a tick, followed a few days later by a rash, usually on the hands and feet, spreading to the trunk and face. Rocky Mountain spotted fever is found throughout the Western Hemisphere and is the most frequently reported rickettsial illness in the US. Without prompt treatment it can be fatal.

Prevention: Observe insect precautions, especially in areas that are likely to harbor ticks. (See Ticks.) Domestic animals should wear a tick-preventive product and be checked regularly after they have spent time outdoors.

Schistosomiasis

Schistosomiasis (bilharzia) is acquired through contact with larvae-infested fresh water. The parasite lives in humans, and its eggs are excreted in stool and urine, ending up in water where they live in certain freshwater snails. The snails in turn release tiny free-swimming larvae (called cercariae) into the water. When humans come into contact with infested water, the cercariae penetrate the unbroken skin and migrate to veins around the liver or bladder where they mature into flatworms or flukes called schistosomes. A few hours after contact with cercariae, an itchy rash occurs (in some persons) where the cercariae enter the body ("swimmers itch"); this usually resolves within a day. Weeks later the adult worms begin to produce eggs, and the person may experience influenza-like symptoms as well as diarrhea and hives. Long-term consequences include severe liver disease, kidney failure, and bladder cancer. Schistosomiasis occurs throughout the tropics and subtropics and is endemic in many developing countries. Travelers are usually infected by bathing, swimming, wading, boating, or rafting in infested water. Even brief water exposure can lead to infection.

Prevention: Never assume that freshwater is free of schistosomes in an endemic area; even deep lake water far from offshore cannot be regard as safe. Avoid swimming or wading in fresh water in areas with poor sanitation or where cases of schistosomiasis have occurred. If water exposure cannot be avoided, wear protective footwear or clothing. Rubber boots and wetsuits are protective. If contact with fresh water cannot be avoided, towel dry vigorously, as cercariae die quickly when removed from water and cannot survive drying.

Scombroid Poisoning

Scombroid poisoning is caused by ingesting bacterial toxins from spoiled fish (fresh or canned) such as bonito, mackerel, skipjack, and tuna; other fish have also produced scombroid poisoning (e.g., amberjack, anchovy, bluefish, herring, mahi-mahi, salmon, sardine, swordfish, and trout). Once the fish is spoiled, neither refrigeration nor cooking can prevent scombroid if the fish is consumed. Symptoms occur within an hour of eating spoiled fish (may taste strong or peppery or make one's mouth tingle) and can include flushing, bright red rash, headache, and palpitations. Hives, dizziness, shortness of breath, abdominal pain, diarrhea, nausea, vomiting, generalized edema (swelling), and redness of the eyes can also occur. The rash usually lasts about 2 to 5 hours and the other symptoms resolve within 3 to 36 hours.

Prevention: Avoid consuming fish that tastes strange or causes any sensation of numbness. Scombroid is usually a short-lived illness. Antihistamines (e.g., diphenhydramine [Benadryl]) provide symptomatic relief as do bronchodilators, when necessary. Adrenaline may be required in rare, severe cases.

Tapeworms

Tapeworms can be transmitted to humans who eat raw, undercooked, or smoked meat or fish containing tapeworm larvae, which then invade the small intestine of the human host. Symptoms range from vague abdominal discomfort to pain, diarrhea, and weight loss. Beef tapeworms occur in central and eastern Africa, central Asia, Central and South America, the Middle East, and Southeast Asia. Pork tapeworms occur in parts of Africa, Central and South America, parts of southern Europe, the Philippines, Southeast Asia, India and Mexico. Travelers at the highest risk are those who are exposed to unsanitary conditions, particularly water or food contaminated with human or animal waste.

Prevention: Observe food and beverage precautions and avoid consumption of undercooked beef, pork, or fish, as well as salted, dried, or pickled meat-derived products. Avoid unprocessed water, ice, raw vegetables, fruits with skin that have not been thoroughly washed with clean water, and other food items processed in unsanitary conditions.

Typhus

Typhus is an infection caused by bacterial organisms called rickettsiae. Typhus occurs in several forms and is usually transmitted to humans by the bites of lice, fleas, mites, or ticks. Symptoms occur from 6 to 18 days after exposure and include high fever, headache, and rash; respiratory and neurological symptoms can also occur. See also Rocky Mountain Spotted Fever., another tick-borne rickettsial infection.

Epidemic typhus is spread when infected body lice or their feces contaminate a bite, an abrasion, or the eyes or through the inhalation of dried feces and occurs in regions of Africa, South America, and Russia. The disease can spread rapidly when large numbers of people are living in crowded, unsanitary conditions, and incidence tends to increase in winter. Symptoms begin suddenly about 10 to 14 days after exposure. The rash typically appears on the torso and spreads over the body. The disease can be relatively mild; however, if left untreated it can result in death.

Murine typhus is spread by fleas that live on mice and rats and occurs when feces of infectious fleas contaminate a bite or skin abrasion, usually when a person scratches or rubs a bite or through the inhalation of dried feces. The disease occurs worldwide (especially in tropical and subtropical areas), wherever people live in close contact with rodents. Symptoms occur 1 to 2 weeks after contact and last for 6 to 13 days. The disease is typically mild, and fatalities are rare.

Scrub typhus is spread by the bite of infected mites while walking through scrub (the cleared areas of jungle or forest) and is endemic in northern Australia, South Asia, Southeast Asia, and the South Pacific. Close examination of skin will show 1 or more small black scabs at the site of the mite bites. Symptoms occur 6 to 18 days after exposure; muscle pain and swollen lymph glands may also occur. Mortality rates are low, but serious neurological symptoms can occur if the disease is not treated.

Prevention: Observe insect precautions and good personal hygiene. Avoid unsanitary, crowded conditions. If walking through scrub in risk areas, treat clothing with permethrin, cover exposed skin, and wear trousers tucked into boots.