Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but TB bacteria can also attack other parts of the body such as the kidney, spine, and brain. If not treated properly, TB disease can be fatal.
Not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist:
- Latent TB Infection: TB bacteria can live in the body without making you sick. This is called latent TB infection. People with latent TB infection do not feel sick and do not have any symptoms. People with latent TB infection are not infectious and cannot spread TB bacteria to others. However, if TB bacteria become active in the body and multiply, the person will go from having latent TB infection to being sick with TB disease. About 10% of those having Latent TB will go on to develop active TB disease.
- Active TB Disease: TB bacteria become active if the immune system can't stop them from growing. When TB bacteria are active (multiplying in your body), this is called TB disease. People with TB disease are sick. They may also be able to spread the bacteria to people they spend time with every day.
Symptoms of Active TB Disease
- A bad cough that lasts three weeks or longer
- Pain in the chest
- Coughing up blood or sputum
- Weakness or fatigue
- Weight loss
- No appetite
- Sweating at night
Complications of TB
Once a person is infected with TB bacteria (LTBI), the chance of developing TB disease is higher if the person:
- Has HIV infection;
- Has been recently infected with TB bacteria (in the last 2 years);
- Has other health problems, like diabetes, that make it hard for the body to fight bacteria;
- Abuses alcohol or uses illegal drugs; or
- Was not treated correctly for TB infection in the past.
Testing for TB
Two tests may be used to detect TB bacteria in the body: a TB skin test (TST) or a TB blood test. At Oregon State, incoming students from high-risk countries will be required to have the TB blood test. If you have a positive reaction to the test, you will be given a chest X-ray to see if you have TB disease.
TB Screening Requirements at Oregon State University
Students from countries identified as high TB risk are required to complete TB screening upon arrival at Oregon State. Students from exempt countries who have lived in a high-risk country for more than six (6) months are advised to complete a TB screening as well. The TB screening will be available through OSU Student Health Services. In many cases, TB screening will be included in the new student orientation schedules as coordinated by INTO-OSU and OSU International Programs. The testing must be completed within the United States, so please do not pursue advance testing in your country prior to your arrival. If you are from one of the high-risk countries, please expect to complete your TB screening upon arrival at OSU.
How TB Spreads
TB is spread through the air from one person to another. The TB bacteria are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, speaks, or sings. People nearby may breathe in these bacteria and become infected.
TB is NOT spread by:
- Shaking someone’s hand
- Sharing food or drink
- Touching bed linens or toilet seats
- Sharing toothbrushes
How TB is Treated
- Treatment for Latent TB Infection: If you have latent TB infection but not TB disease, your health care provider may want you be treated to keep you from developing TB disease. Treatment of latent TB infection is essential to controlling and eliminating TB in the United States. The decision about taking treatment for latent TB infection will be based on your chances of developing TB disease.
- Treatment for Active TB Disease: TB disease can be treated by taking several drugs, usually for six to nine months. It is very important to finish the medicine, and take the drugs exactly as prescribed.
How to Prevent TB
Travelers should avoid close contact or prolonged time with known TB patients in crowded, enclosed environments (for example, clinics, hospitals, prisons, or homeless shelters).
Travelers who will be working in clinics, hospitals, or other health care settings where TB patients are likely to be encountered should consult infection control or occupational health experts. They should ask about administrative and environmental procedures for preventing exposure to TB. Once those procedures are implemented, additional measures could include using personal respiratory protective devices.
If you think you have been exposed to someone with TB disease, contact your health care provider or local health department to see if you should be tested for TB. Be sure to tell the doctor or nurse when you spent time with someone who has TB disease.
Source: Centers for Disease Control and Prevention - www.cdc.gov/tb