Travel-related infections are diseases that tourists and other visitors to foreign countries are at increased risk of contracting.
When Americans travel to other countries, they may be exposed to many bacterial, viral, parasitic, and fungal infections that they would not encounter in the United States. With different climates, sanitation, and hygiene practices (such as bathing and defecating 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 people from developed countries such as those in Europe and North America at higher risk of travel-related infections. One of the most common ailments is traveler's diarrhea (dye-uh-REEuh), which can be caused by a variety of bacterial, parasitic, and viral infections. According to the Centers for Disease Control and Prevention (CDC), between 20 and 50 percent of these travelers experience diarrhea.
Some travel-related infections are spread through the bites of insects such as mosquitoes, which carry malaria and yellow fever; or flies, for example, the tsetse (SET-see) fly, which can carry trypanosomiasis (trihpan-o-so-MY-uh-sis). Other diseases, including schistosomiasis (SHIStuh-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.
Malaria is a disease that is transmitted through a mosquito bite. It is a public health problem throughout many countries and affects 300 to 500 million people 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, including extreme tiredness, muscle aches, nausea (NAW-zee-uh), and chills. The Plasmodium parasite typically invades red blood cells. Many symptoms of the disease are related to the destruction of infected red blood cells and the resulting anemia * . If left untreated, malaria can cause seizures * , kidney * failure, and death. Medications can treat malaria and prevent this disease in travelers. Malarial prophylaxis (pro-fee-LACK-sis, medicine that prevents malaria) is strongly recommended for individuals traveling to endemic * areas. The specific medications to be used vary regionally, depending on the resistance patterns of the parasite. For those residing in malaria hot spots, extensive trials of a potentially effective antimalarial vaccine were initiated in 2008; however, the vaccine is still under development as of 2016.
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 can also 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.
A bite from an infected mosquito can transmit filariasis (fihluh-RYE-uh-sis), a parasitic disease that affects the lymphatic system * . When the infected mosquito feeds, tiny worms pass from it into 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 can also 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 highly 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, including 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 that 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 six 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.
Schistosomiasis is a disease caused by parasitic Schis-tosoma (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 * . In certain areas of the world, the free-swimming larvae of Schistosoma that primarily infect aquatic birds may penetrate the skin of humans and lead to an itchy rash called swimmer's itch. This symptom resolves over a short period of time and does not lead to systemic * infection.
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 occur among individuals who contracted 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. Typhus was a common cause of death in military camps and concentration camps up through the end of World War II in 1945. However, it is treatable with antibiotics and preventable with good personal hygiene.
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 disease and Lassa fever.
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 desire 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.
American trypanosomiasis is found in the Western hemisphere. It is also known as Chagas disease. It is transmitted to humans by the bite of the reduviid bug (kissing bug). The disease is caused by the protozoan parasite Trypanosoma cruzi. WHO estimates that 16 to 18 million persons are infected with T. cruzi every year. Acute infections are usually mild, but repeated infections can lead to damage to the digestive tract or heart, which may appear as much as 20 years after the first infection.
Tuberculosis (TB) reemerged as a major public health problem in the early 2000s. Experts estimate that up to one-third of the world population has been infected by a TB bacterium at some point. The reemergence of this disease is becoming even more troubling because multidrug-resistant strains of TB are also emerging. Therefore, travelers who develop any symptoms suspicious of TB (low-grade fevers, weakness, night sweats, cough, and weight loss) should see a doctor as soon as the symptoms appear.
Avian influenza (also called H5N1) is largely confined to birds such as chickens, ducks, and geese. However, people who have had prolonged close contact with infected birds have developed the disease. As of mid-2016, sustained human-to-human transmission had not occurred.
Although primarily affecting birds, a relatively small number of human cases have been reported. In 2014, 52 cases were reported worldwide. The mortality (death) rate among humans between 2005 and 2015 was approximately 50 percent. Global travel is seen as a major potential factor in the possible spread of this virus, especially with marked increases in travel to the Far East, Indonesia, and the Indian subcontinent.
Travelers can take precautions to reduce their risk of contracting an infectious disease while abroad. Experts offer the following tips for staying healthy:
Prophylaxis * * and prophylaxis. People can also consult the CDC's Yellow Book, which contains detailed health recommendations for travelers and is updated every two years. The 2016 Yellow Book can also be accessed online.
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, including those for diphtheria and tetanus. If someone plans to travel abroad, they should discuss travel plans with a doctor so that any necessary vaccinations can be given.
See also Bacterial Infections • Bites and Stings • Brain Parasites • Chagas Disease • Cholera • Dengue Fever • Diarrhea • Ebola Virus Disease • Elephantiasis • Fever • Filariasis • Fungal Infections • Global Health Issues: Overview • Hepatitis • Influenza • Intestinal Parasites • Malaria • MERS (Middle East Respiratory Syndrome) • Parasitic Diseases: Overview • Plague • Rabies • Severe Acute Respiratory Syndrome (SARS) • Shigellosis (Bacillary Dysentery) • Tetanus (Lockjaw) • Trypanosomiasis • Tuberculosis • Typhoid Fever • Typhus • Vaccines and Immunization • Viral Infections • Yellow Fever • Zika Virus Infection
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* parasite (PAIR-uh-site) is an organism such as a protozoan (one-celled animals), worm, or insect that must live on or inside a human or other organism to survive. An animal or plant harboring a parasite is called its host.
* anemia (uh-NEE-me-uh) is a blood condition in which there is decreased hemoglobin in the blood or a lower than normal number of red blood cells.
* 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.
* endemic (en-DEH-mik) describes a disease or condition that is continually present in a specific population or geographic area.
* gastrointestinal (gas-tro-in-TEStih-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.
* lymphatic system (lim-FAH-tik) 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 nodes (LIMF) are small bean-shaped masses of tissue containing 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, like a very deep sleep. A person in a coma cannot be awakened, and cannot move, see, speak, or hear.
* urinary tract (YOOR-ih-nair-e TRAKT) 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.
* systemic (sis-TEM-ik) is a problem affecting the whole system or whole body, as opposed to a localized problem that affects only one part of the body.
* prophylaxis (pro-fih-LAK-sis) means taking specific measures like using medication or a device to help prevent infection, illness, or pregnancy.
* vaccinations (vak-sih-NAYshunz), 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 the disease that can result if a person is exposed to the germ itself.