- Tuberculosis (TB) is a bacterial infection that occurs worldwide and is acquired through inhalation of airborne droplets from an infected person.
- Risk is low for most travelers but increases sharply in people with HIV or a weakened immune system, malnutrition, diabetes, and in tobacco smokers.
- Symptoms include fever, night sweats, weight loss, fatigue, cough (with or without blood), and chest pain.
- Consequences of infection include inflammation of the membranes of the lungs, brain, and spinal cord.
- Prevention for travelers to the highest-risk destinations includes TB screening tests for long-stay travelers, health care workers (HCWs), and those with anticipated exposure in prisons, homeless shelters, refugee camps, or shanty towns. Travelers should avoid public transportation and crowded public places whenever possible at these destinations.
- Bacille Calmette-Guérin (BCG) vaccine should be considered for healthy children younger than 5 years who will be living for more than 1 year in highly endemic areas. Tuberculin-negative health care workers planning to work where TB is common (especially multidrug-resistant TB), may consider vaccination with BCG; however, its effectiveness in adults is unproven and not recommended by most authorities.
TB is a bacterial infection caused by Mycobacterium tuberculosis and is strongly associated with poverty, overcrowding, and malnutrition. Drug-resistant TB (which includes multidrug-resistant TB [MDR-TB] and extensively drug-resistant TB [XDR-TB]) is caused by bacteria that do not respond to powerful medicines against this infection. TB is present in almost all countries. Over 95% of cases and deaths occur in developing countries. The lungs are frequently affected by TB, but any organ of the body can be affected. A vaccine to prevent TB has not yet been developed; however, measures to control TB do exist.
TB occurs worldwide. High TB burden occurs in Afghanistan, Bangladesh, Brazil, Burma, Cambodia, China, Democratic Republic of the Congo, Ethiopia, India, Indonesia, Kenya, Mozambique, Nigeria, Pakistan, Philippines, Russia, South Africa, Tanzania, Thailand, Uganda, Vietnam, and Zimbabwe. One-third of the world's population is infected with latent TB (i.e., the patient is infected but does not have active TB) and is at risk of developing the disease. TB causes one-third of all deaths in HIV-infected persons. Most MDR-TB patients live in Eastern Europe, India, South Africa, or China.
TB is transmitted from person-to-person through inhalation of airborne droplets. It has also been spread from an open wound or contaminated equipment, albeit rarely. In most instances, transmission involves patients with extensive lung disease and sputum smears that show the presence of TB bacteria.
The risk of acquiring TB is low in otherwise healthy people but increases sharply in people with HIV or other causes of a weakened immune system, malnutrition, or diabetes, and in tobacco smokers. Kidney disease, silicosis (lung disease caused by inhaling silica dust), age less than 5 years, prolonged corticosteroid use, and cancer are also associated with the risk of developing active TB.
Once infected and after a positive skin or blood test, if active TB is to develop it usually will be within the first 2 years after initial infection.
For most travelers, the risk of TB infection is low even in high-risk countries. Risk increases with endemicity of TB in the area visited, duration of travel, and activity. MDR-TB presents an extra risk in India, China, Central Asia, Eastern Europe, and Russia.
Activities that put travelers most at risk of contracting TB include:
- Closely interacting with the local population
- Visiting friends and relatives
- Working in high-risk situations (e.g., HCWs and those with anticipated exposure in prisons, homeless shelters, refugee camps, or shanty towns)
- Utilizing public transportation
- Frequenting crowded public places where infected persons may be coughing
- Employing domestic help (TB screening is recommended)
- Eating or drinking unpasteurized milk and milk products (from infected cattle)
On aircraft, a very low risk of infection exists for travelers sitting within a 2-seat range behind, in front of, or beside an infectious traveler.
Patients with TB usually have no symptoms following the initial infection, and the only marker is a positive TB test result. Symptoms may develop later. Primary TB (which is the infection acquired by a person with no history of TB) is uncommon, and mostly occurs in children younger than 5 years and in severely immunocompromised persons.
TB symptoms include fever, night sweats, weight loss, fatigue, cough (with or without blood), and chest pain.
Consequences of Infection
TB can spread to other parts of the body causing inflammation of the membranes of the lungs, brain, and spinal cord.
Need for Medical Assistance
Individuals with a known exposure to an infective case should be screened to identify those who might benefit from treatment. Screening is recommended 8 weeks after the exposure period or later. Some tests may not convert earlier than 8 weeks postexposure.
Persons who develop symptoms (see above) of TB should see their health care provider.
Only persons who are or will be at increased risk for TB infection should be tested for TB prior to travel to establish any baseline exposure or infection with TB. Travelers to areas of the world where TB is highly or moderately endemic should be considered for screening, especially:
- Those who plan to stay more than 3 months
- HCWs who stay longer than 1 month
- Individuals with anticipated exposure in prisons, homeless shelters, refugee camps, or shanty towns
Domestic helpers assisting long-stay residents in high-risk countries should be screened for TB.
Because the greatest risk of developing active TB is within the first 2 years of infection, travelers should have repeat screening conducted at 1- to 2-year intervals if risk continues.
Bacille Calmette-Guérin (BCG) vaccine is used in many developing countries to reduce serious consequences of TB in newborns. BCG vaccine is also recommended by some industrialized countries for long-stay travelers to TB-endemic areas; however, its effectiveness in adults is unproven and not recommended by most authorities.
In North America, pre- and posttravel TB screening tests are recommended rather than BCG vaccine. However, BCG vaccine should be considered for healthy children younger than 5 years who will be living for more than 1 year in highly endemic areas. BCG vaccine might also be considered on an individual basis for tuberculin-negative HCWs planning to work in areas where TB (especially MDR-TB) is common and comprehensive infection-control precautions are not readily available.
Travelers should avoid public transportation and crowded public places in high-risk destinations whenever possible.