Foreign Travel

Travelers should be current on all routine immunizations Overview of Immunization Immunity can be achieved Actively by using antigens (eg, vaccines, toxoids) Passively by using antibodies (eg, immune globulins, antitoxins) A toxoid is a bacterial toxin that has been modified... read more , including COVID-19 COVID-19 COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. Prevention is by vaccination and infection control precautions (eg, face masks, handwashing... read more . Some countries require specific vaccinations (see table Vaccines for International Travel Vaccines for International Travel*, † ). The Centers for Disease Control and Prevention (CDC) website provides general travel and up-to-date immunization information, travel information related to COVID-19, and malaria chemoprophylaxis requirements (also available from the CDC's malaria hotline: 855-856-4713).

The COVID-19 COVID-19 COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. Prevention is by vaccination and infection control precautions (eg, face masks, handwashing... read more pandemic has necessitated limitation of travel to and from various countries. Entry requirements (eg, testing, vaccination, quarantine) change frequently, and patients should be advised to check the website of their nation's health agency (eg, CDC in the US) as well as the destination countries for current recommendations.

Dengue fever Dengue Dengue is a mosquito-borne disease caused by a flavivirus. Dengue fever usually results in abrupt onset of high fever, headache, myalgias, arthralgias, and generalized lymphadenopathy, followed... read more is a mosquito-borne viral infection endemic to the tropical regions of the world in latitudes from about 35° north to 35° south. Outbreaks are most prevalent in Southeast Asia but also occur in the Caribbean, including Puerto Rico and the US Virgin Islands, Oceania, and the Indian subcontinent; more recently, dengue incidence has increased in Central and South America.

A vaccine for dengue is approved in several countries outside the US, but efficacy is only moderate and varies by dengue immune status, serotype, and patient age; studies are ongoing.

People traveling to endemic areas should try to prevent mosquito bites. Effective personal protection measures include applying DEET or picaridin to exposed skin, applying permethrin to clothing, and sleeping under a permethrin-treated mosquito net if sleeping quarters are not air conditioned (see CDC: Prevent Mosquito Bites). These measures also offer protection from other insect-transmitted diseases including Zika Zika Virus (ZV) Infections The Zika virus is a mosquito-borne flavivirus that is antigenically and structurally similar to the viruses that cause dengue, yellow fever, and West Nile virus. Zika virus infection is typically... read more and chikungunya Chikungunya Disease Chikungunya disease is transmitted by the Aedes mosquito. Chikungunya disease usually presents with acute fever. Chronic polyarthritis can persist and be disabling. Diagnosis is confirmed... read more .

Influenza Influenza Influenza is a viral respiratory infection causing fever, coryza, cough, headache, and malaise. Mortality is possible during seasonal epidemics, particularly among high-risk patients (eg, those... read more is common in international travelers; hence annual influenza vaccines Influenza vaccines Influenza is a viral respiratory infection causing fever, coryza, cough, headache, and malaise. Mortality is possible during seasonal epidemics, particularly among high-risk patients (eg, those... read more are indicated for all travelers.

Malaria Malaria Malaria is infection with Plasmodium species. Symptoms and signs include fever (which may be periodic), chills, rigors, sweating, diarrhea, abdominal pain, respiratory distress, confusion... read more is endemic in much of Africa, Asia, Latin America, and other regions. The CDC provides information about specific countries where malaria is transmitted (see Yellow Fever and Malaria Information, by Country), types of malaria, and resistance patterns.

Travelers to endemic regions should take preventive measures for malaria Prevention Malaria is infection with Plasmodium species. Symptoms and signs include fever (which may be periodic), chills, rigors, sweating, diarrhea, abdominal pain, respiratory distress, confusion... read more , including chemoprophylaxis . Although the RTS,S/AS01 (RTS,S) malaria vaccine is recommended for children living in regions with moderate to high Plasmodium falciparum malaria transmission, this vaccine is not recommended for travelers to those regions.

Schistosomiasis Schistosomiasis Schistosomiasis is infection with blood flukes of the genus Schistosoma, which are acquired transcutaneously by swimming or wading in contaminated freshwater. The organisms infect the... read more is common and is caused by exposure to contaminated freshwater in Africa, Southeast Asia, China, and eastern South America. Risk of schistosomiasis can be reduced by avoiding freshwater activities in areas where schistosomiasis is common. Asymptomatic travelers with freshwater exposure in endemic regions should be screened by serologic testing for antibody to the adult worm at 6 to 8 weeks following their most recent exposure. Alternately, travelers may elect to presumptively treat a potential exposure with praziquantel, at 6 to 8 weeks after the most recent potential exposure: 20 mg/kg orally twice per day for one day (Schistosoma mansoni, S. haematobium, S. intercalatum) or 20 mg/kg 3 times per day for one day (S. japonicum, S. mekongi).

Traveler’s diarrhea Traveler’s Diarrhea Traveler’s diarrhea is gastroenteritis that is usually caused by bacteria endemic to local water. Symptoms include vomiting and diarrhea. Diagnosis is mainly clinical. Treatment is with replacement... read more (TD) is the most common health problem among international travelers. TD is usually self-limited, typically resolving in 5 days; however, 3 to 10% of travelers with TD may have symptoms lasting > 2 weeks, and up to 3% of travelers have TD lasting > 30 days. TD lasting < 1 week requires no testing. For persistent TD, laboratory testing Testing Stool is 60 to 90% water. In Western society, stool amount is 100 to 200 g/day in healthy adults and 10 g/kg/day in infants, depending on the amount of unabsorbable dietary material (mainly... read more is done.

Self-initiated treatment is indicated for moderate to severe symptoms, especially if vomiting, fever, abdominal cramps, or blood in the stool are present. Treatment of traveler's diarrhea Treatment Traveler’s diarrhea is gastroenteritis that is usually caused by bacteria endemic to local water. Symptoms include vomiting and diarrhea. Diagnosis is mainly clinical. Treatment is with replacement... read more is with an appropriate antibiotic (eg, azithromycin, 500 mg or one gram once, or 500 mg once a day for 1 to 3 days). Additional measures include loperamide (except in patients with fever, bloody stools, or abdominal pain and in children < 2 years); replacement of fluids; and, in older people and small children, electrolytes (eg, oral rehydration solution).

Measures that may decrease the risk of TD include

Prophylactic antibiotics are effective in preventing diarrhea, but because of concerns about adverse effects and development of resistance, they should probably be reserved for immunocompromised patients. One option is rifaximin, 200 mg once or twice a day.

Road traffic crashes are the most frequent cause of death of international travelers, with the exception of older adults. Travelers should at all times use a seat belt in vehicles and a helmet when cycling. Travelers should avoid motorcycles and mopeds and avoid riding on bus roofs or in open truck beds.

Drowning is another common cause of death while abroad. Travelers should avoid beaches with turbulent surf and avoid swimming after drinking alcoholic beverages.

The most common medical problem after travel is

The most common potentially serious diseases are

People can also acquire lice Lice Lice can infect the scalp, body, pubis, and eyelashes. Head lice are transmitted by close contact; body lice are transmitted in cramped, crowded conditions; and pubic lice are transmitted by... read more and scabies Scabies Scabies is an infestation of the skin with the mite Sarcoptes scabiei. Scabies causes intensely pruritic lesions with erythematous papules and burrows in web spaces, wrists, waistline... read more after being in crowded living conditions or places where hygienic measures are poor.

Some diseases become evident months after a traveler has returned home; a travel history with exposure risks is a useful diagnostic clue when patients present with a puzzling illness. The International Society of Travel Medicine (www.istm.org) has lists of travel clinics. Many of these clinics specialize in assisting travelers who are ill after their return home. For health care practitioners, the Centers for Disease Control provides assistance and information to help patients returning from travel abroad.