When people travel to other countries, they are at increased risk for travel-related infections.
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What Are Travel-related Infections?
When travelers go abroad, they may be exposed to many bacterial, viral, parasitic, and fungal infections that they would not come into contact with in the United States. With different climates, sanitation, and hygiene practices (such as bathing and urinating in the same water source), some diseases that are rarely or never seen in the United States are common in other parts of the world. The risk of infectious disease is greatest in tropical and subtropical countries because warm, moist climates offer an ideal environment for the survival and growth of certain organisms. Visiting developing regions of the world, particularly Africa (especially sub-Saharan Africa), southeast Asia, and Central and South America, also puts travelers at higher risk for travel-related infections. One of the most common ailments is "traveler's diarrhea" (dye-uh-REE-uh), which can be caused by a variety of bacterial, parasitic, and viral infections. According to the U.S. Centers for Disease Control and Prevention (CDC), between 20 and 50 percent of travelers experience diarrhea.
How Are Travel-related Infections Spread?
Some travel-related infections are spread through the bites of insects, such as mosquitoes (which carry malaria, mah-LAIR-e-uh, and yellow fever) or flies (for example, the tsetse, SET-see, fly can carry trypanosomiasis, trih-pan-o-so-MY-uh-sis). Other diseases, including schistosomiasis (shis-tuh-so-MY-uh-sis), can be contracted from swimming, wading, or bathing in contaminated water. Eating or drinking contaminated food or water is another common way of contracting disease, especially traveler's diarrhea.
What Are Some Common
Malaria is a disease that is transmitted through a mosquito bite and affects 300 to 500 million people worldwide each year, according to the World Health Organization (WHO). When an infected mosquito bites a human, the Plasmodium (plaz-MO-dee-um) parasite causes fever and symptoms similar to those of the flu, such as extreme tiredness, muscle aches, nausea (NAW-zee-uh), and chills. If left untreated, malaria can cause seizures * , kidney * failure, and death. Medications can treat malaria and prevent disease in travelers.
Cholera (KAH-luh-ruh) is a gastrointestinal * disease that causes watery diarrhea, vomiting, and other symptoms. Without treatment, it can lead to dehydration * and even death. People develop cholera by eating food or drinking water that has been contaminated with the cholera bacterium, Vibrio cholerae (VIH-bree-o KAH-luh-ray). Eating contaminated shellfish or coming into contact with the feces * of an infected person also could infect someone. A person with cholera is treated to replace fluids lost through vomiting or diarrhea; some antibiotics may reduce the severity and length of the illness.
* seizures (SEE-zhurs) are sudden bursts of disorganized electrical activity that interrupt the normal functioning of the brain, often leading to uncontrolled movements in the body and sometimes a temporary change in consciousness.
* kidney is one of the pair of organs that filter blood and remove waste products and excess water from the body in the form of urine.
* gastrointestinal (gas-tro-in-TES-tih-nuhl) means having to do with the organs of the digestive system, the system that processes food. It includes the mouth, esophagus, stomach, intestines, colon, and rectum and other organs involved in digestion, including the liver and pancreas.
* dehydration (dee-hi-DRAY-shun) is a condition in which the body is depleted of water, usually caused by excessive and unreplaced loss of body fluids, such as through sweating, vomiting, or diarrhea.
* feces (FEE-seez) is the excreted waste from the gastrointestinal tract.
Dengue (DENG-gay) fever is caused by a virus from the Flavivirus (FLAY-vih-vy-rus) group transmitted to humans via the bite of an infected mosquito. According to the CDC, up to 100 million people worldwide develop symptoms of dengue fever each year, such as fever, severe headaches, joint pain, and rashes. Dengue hemorrhagic (heh-muh-RAH-jik) fever is a severe form of dengue that is associated with bruising easily, bleeding from the nose or gums, and bleeding internally, in addition to the other symptoms of dengue fever. No medication can treat either form of the illness. Doctors recommend that people who have dengue fever drink plenty of fluids to avoid dehydration and take acetaminophen (uh-see-teh-MIH-noh-fen) for pain relief.
A bite from an infected mosquito can transmit filariasis (fih-luh-RYE-uh-sis), a parasitic disease that affects the lymphatic system * . When the infected mosquito feeds, tiny worms pass from it to the person, where they travel to and grow in the lymph vessels. Someone with this disease may not have noticeable symptoms, but filariasis can lead to permanent damage to the kidneys and lymphatic system. It also can progress to a condition called elephantiasis (eh-luh-fan-TIE-uh-sis), in which fluid builds up in parts of the body and causes swelling and disfigurement. The condition can be treated with medication.
Viral hepatitis (heh-puh-TIE-tis) is a viral infection of the liver * that leads to inflammation of the organ. Infections caused by the hepatitis B and C viruses are contracted sexually or through contact with contaminated blood or other body fluids, but hepatitis A virus is more contagious and is the hepatitis virus that more commonly infects travelers. It can spread through person-to-person contact or through contaminated water and food, especially shellfish and raw vegetables and fruits. A person with hepatitis may have symptoms similar to those of the flu, such as fever, chills, and weakness. People with hepatitis A may need extra fluids and rest, but most recover without medication.
Travelers who are bitten by an infected sand fly can develop leishmaniasis (leesh-muh-NYE-uh-sis), a disease caused by Leishmania (leesh-MAH-nee-uh) parasites that can affect the skin or the internal organs. People with the skin disease often have skin sores, which may spread to cause facial disfigurement. Those with the internal form of the disease experience fever and an enlarged spleen * or liver and may need to be hospitalized.
Fleas that bite rodents infected with the bacterium Yersinia pestis (yer-SIN-e-uh PES-tis) can transmit plague (PLAYG) to humans. Two to 6 days after becoming infected with plague, a person may have swollen and tender lymph nodes * , fever, cough, chills, and belly pain. The plague can lead to severe respiratory illness, shock * , and death if a person is not treated with antibiotics.
* lymphatic (lim-FAH-tik) system is a system that contains lymph nodes and a network of channels that carry fluid and cells of the immune system through the body.
* liver is a large organ located beneath the ribs on the right side of the body. The liver performs numerous digestive and chemical functions essential for health.
* spleen is an organ in the upper left part of the abdomen that stores and filters blood. As part of the immune system, the spleen also plays a role in fighting infection.
* lymph (LIMF) nodes are small, bean-shaped masses of tissue that contain immune system cells that fight harmful microorganisms. Lymph nodes may swell during infections.
* shock is a serious condition in which blood pressure is very low and not enough blood flows to the body's organs and tissues. Untreated, shock may result in death.
* paralysis (pah-RAH-luh-sis) is the loss or impairment of the ability to move some part of the body.
* coma (KO-ma) is an unconscious state in which a person cannot be awakened and cannot move, see, speak, or hear.
Although rabies (RAY-beez) in humans is rare in the United States, people who travel to other countries may be at higher risk for infection. The virus that causes rabies, from the Rhabdoviridae (rab-doh-VEER-ih-day) family, is transmitted to humans through a bite from an infected animal, and without treatment rabies can cause paralysis * , seizures, coma * , and death. A person who has been bitten by an animal suspected of having rabies can receive injections of the rabies vaccine to prevent the infection from developing.
Schistosomiasis is a disease caused by parasitic Schistosoma (shis-tuh-SO-mah) worms that infect humans when they come into contact with contaminated water. The worms must spend part of their life cycle growing in freshwater snails before they enter and infest humans. Common symptoms include rash, fever, muscle aches, and chills. Years later, if left untreated, schistosomiasis can lead to permanent liver damage or damage to the urinary tract * .
According to the CDC, typhoid (TIE-foyd) fever affects up to 16 million people worldwide each year, although only about 400 cases occur in the United States (and the majority of those contract it while traveling abroad). A person who has contact with water or food contaminated with Salmonella typhi (sal-muh-NEH-luh TIE-fee) bacteria may develop symptoms such as fever, weakness, rash, stomach pain, or headache. Typhoid fever is treatable with antibiotics.
Typhus (TY-fis) is transmitted by the bites of fleas or lice infected with Rickettsiae (rih-KET-see-eye) bacteria. Symptoms of typhus include an extremely high fever, rash, nausea, joint pain, and headache. Patients often become very sick, and without treatment the disease can be life threatening. However, it is treatable with antibiotics.
Viral hemorrhagic fevers
Viral hemorrhagic (heh-muh-RAH-jik) fevers (VHF) are a group of rare but potentially life-threatening viral illnesses that cause symptoms ranging from fever, extreme tiredness, and dizziness to bleeding from the eyes and ears, kidney failure, and seizures. Humans contract VHF after exposure to people or animals that have been infected with one of a variety of viruses. Examples of VHF include Ebola virus infection and Lassa fever.
The yellow fever virus (from the flavivirus group) is transmitted to humans by a mosquito bite. Within a week of being infected, a person may experience fever, muscle aches, nausea, or vomiting. Most people recover within 3 to 4 days, but according to WHO about 15 percent of people with yellow fever go on to develop a more serious form of the disease that can cause bleeding, kidney failure, and death. An effective vaccine is available for yellow fever and is often recommended for travelers who will be visiting areas where the disease is found.
* urinary (YOOR-ih-nair-e) tract is the system of organs and channels that makes urine and removes it from the body. It consists of the urethra, bladder, ureters, and kidneys.
African trypanosomiasis is a parasitic illness commonly known as sleeping sickness. The Trypanosoma (trih-pan-o-SO-mah) parasite is transmitted to humans through a bite from the tsetse fly, after which a person may develop a skin sore, high fever, extreme tiredness, swollen lymph nodes, and swelling around the eyes. The disease is called sleeping sickness because people who have an advanced form of it can have an uncontrollable urge to sleep. If untreated, trypanosomiasis can cause the brain and membranes around the brain to swell and become inflamed. The disease can be treated with hospitalization and medication.
How Can Travelers Protect Themselves
Travelers can take precautions to reduce their risk of contracting a disease while abroad. Experts offer the following tips for staying healthy:
Do not swim, wade, or bathe in freshwater sources, the ocean near beaches that are contaminated with human feces, or pools that are not chlorinated.
- Use only bottled water or water that has been boiled for drinking and brushing teeth.
- Avoid drinks with ice in them, as the ice may be from unsafe water. Canned or bottled beverages are the safest drinks. Carefully wiping the top of the can or bottle before drinking from it may remove disease-causing agents.
- Do not eat raw foods, particularly meat and salad. Avoid raw fruits and vegetables unless you peel them yourself.
- Avoid shellfish and other fish, which can be toxic at certain times of the year even if they have been cooked.
- Do not buy foods from street vendors.
- Avoid unpasteurized milk (milk that has not been processed with heat to kill parasites and bacteria) and dairy products.
- Prevent insect bites by wearing long sleeves and long pants in light colors so the insects can be seen easily.
- Use repellent and sleep under mosquito netting.
- Stay inside at times when biting insects are most active, mostly dawn and dusk.
Certain vaccinations * can help protect against infectious diseases that are common in different geographic areas. Depending on the destination and the length of the planned trip, travelers may receive immunizations for hepatitis, meningococcal infection, typhoid fever, or yellow fever, as well as any vaccinations in the regular immunization schedule that the person may have missed or may need to renew, such as those for diphtheria and tetanus. If someone plans to travel abroad, it is important to discuss travel plans with a doctor so that any necessary vaccinations can be given.
* vaccinations (vak-sih-NAY-shunz), also called immunizations, are the giving of doses of vaccines, which are preparations of killed or weakened germs, or a part of a germ or product it produces, to prevent or lessen the severity of a disease.
U.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton
Road, Atlanta, GA 30333. The CDC maintains the Travelers' Health
Information pages at its website. The Travelers' Health section
offers information about many travel-related infections, where they are
found, and the latest research on how to prevent them.