Tuberculosis (TB) is an airborne infection caused by the bacterium Mycobacterium tuberculosis. Although TB primarily affects the lungs, other organs and tissues may be affected as well. After decades of decline, the incidence of TB began increasing again in 1985. By 1992, the incidence had increased over 20 percent. Starting in 1992, however, the trend reversed, and the rate began to decline. The estimated decline in the number of reported tuberculosis cases was 34 percent between 1992 and 1999. This has been attributed to improved TB control programs.

It is important to understand that there is a difference between being infected with TB and having TB disease. Someone who is infected with TB has the TB germs, or bacteria, in his/her body. The body's defenses, though, are protecting them from the germs, and they are not sick. Someone with TB disease is sick and, if not properly treated, can spread the disease to other people. A person with symptoms of TB disease or evidence of infection needs to be seen by a physician.

Several symptoms are associated with TB, including prolonged coughing (including coughing up of blood), repeated night sweats, unexplained weight loss, loss of appetite, fever, chills, and general lethargy. Because these signs may be indicative of other diseases as well, a person must consult a physician to determine the cause of these symptoms.

TB is spread by an airborne germ; therefore, someone with TB can spread the germs by coughing, sneezing, laughing, or singing. Repeated exposure to someone with TB disease is generally necessary, however, before a person will become infected. TB germs cannot be spread by touch or the sharing of utensils used by an infected person. Sexual contact by itself cannot spread the germs, unless extrapulmonary tuberculosis of the genital organs is involved.

The simplest way to find out if you have a TB infection is to get a TB skin test, widely available at clinics or at a doctor' s office. A small amount of testing material is injected under the very top layers of skin on the forearm. In 48 to 72 hours the test is read by a trained person, usually a nurse or doctor. If the test is positive, then you probably have TB infection and the doctor will run more tests, such as a chest x-ray, to determine whether you have active TB disease. In some groups, such as the elderly or those with impaired immunity, a simple skin test may not be enough to determine whether they have TB infection. Further evaluation may be necessary for these individuals if they have symptoms or signs of tuberculosis.

Most TB can be cured. There are drugs that can kill the germs that cause TB, but a person must continually take the prescribed medication, usually for six months. Some patients require a year or more for successful treatment.

If a person stops taking the medicine before completing treatment, the germs may come back more resilient than before. Surviving bacteria may become resistant to the drugs used to treat TB, causing multi-drug resistant tuberculosis (MDR TB).

Anyone can get TB. It strikes people of all races, ages, and income levels. Certain groups are at higher risk. These include:

• people who associate with others with active TB disease
• poor and medically underserved
• homeless people
• those who come from countries with high TB incidence rates
• people in congregate settings, such as nursing homes or prisons
• alcoholics and intravenous drug users
• people with medical conditions that impair their immunity, such as HIV or AIDS, or who are undergoing treatments likely to impair their immune systems
• the elderly
• health care workers and others who come in contact with high-risk populations, e.g. prison guards

The 1999 total number of cases of tuberculosis in the United States (17,531), represents the seventh consecutive year the number of reported TB cases has decreased, resulting in the lowest rate for reported TB cases (6.4 per 100,000) since national surveillance began in 1953.

Even though there was a decrease in the number of TB cases among U.S.-born persons, 1999 data shows an increased number of cases among persons born outside of the United States and its territories since 1994. In 1999, 43 percent of reported tuberculosis cases were in foreign-born persons.

In 1999, tuberculosis case rates among American Indians, Hispanics, blacks and Asian/Pacific Islanders were 4,5,6 and 15 times higher, respectively, than among whites.

The AIDS epidemic was considered a major factor in the increase in TB cases. HIV's suppression of the immune system both opens the door to new active infection and permits activation of latent disease. The Centers for Disease Control and Prevention estimates that at least 100,000 people in the U.S. are infected with both TB and HIV.

Each health department should assess the prevalence, incidence, and sociodemographic characteristics of cases and infected persons in their community. On the basis of these data, tuberculin screening programs should be targeted to each community's high-risk groups. It is extremely important that these screening programs undergo regular evaluation of their usefulness.

Tuberculin skin-testing is recommended for diagnostic screening among the following high-risk groups:

• persons with signs, symptoms, and/ or laboratory abnormalities suggestive of clinically active TB
• recent contacts of persons known to have or suspected of having clinically active TB
• those who come from countries with high TB incidence rates
• people in congregate settings, such as nursing homes or prisons
• persons with signs, symptoms, and/ or laboratory abnormalities suggestive of clinically active TB
• recent contacts of persons known to have or suspected of having clinically active TB
• persons with HIV infection
• persons with abnormal chest roentgenograms compatible with past TB
• persons at high risk of infection with M. tuberculosis
• persons who are at risk of spreading disease such as teachers and health care workers

Because it is difficult for some people to successfully complete their tuberculosis treatment, several innovations have been developed. One of these is the use of incentives and enablers, which may be transportation, tokens or food coupons that are given to patients each time they appear at the clinic or doctor's office for treatment. Incentives and enablers are combined with the use of directly observed therapy (DOT). DOT is a system of treatment in which the patient is administered his or her medication by a nurse or health worker and is observed taking the medication.

One recent innovation in TB treatment is the FDA approval of rifater. Rifater is a medication that combines three main drugs (isoniazid, rifampin, and pyrazinamide) used to treat tuberculosis into one pill. This reduces the number of pills a patient has to take each day and makes it impossible for the patient to take only one of the three medications, a common path to the development of multi-drug resistant TB.

In June 1998, the U.S. Food and Drug Administration approved the first new drug for pulmonary tuberculosis in 25 years. The drug, rifapentine (Priftin), is approved for use with other drugs to fight TB. One potential advantage of rifapentine is that it can be taken less often in the final four months of treatment --once a week compared with twice a week for the standard regimen.

Know More - Do More

Tuberculosis is preventable.

Tuberculosis requires persistent diligence to maintain suppression in the United States and worldwide.

Local and state tuberculosis practitioners combat the disease with Directly Observed Therapy (DOT), research and development of innovative diagnosis and treatment, and educational outreach.

More work needs to be done to eliminate tuberculosis in Washington State and worldwide. For more information on tuberculosis or to participate in programs dedicated to eliminating tuberculosis contact:

Local/State

Public Health Seattle/King County
Washington State Department of Health – Tuberculosis Program
Washington State Health Districts
Firland Foundation

National

Centers for Disease Control
Find TB Resources (CDC)
Francis J. Curry National TB Center
New Jersey Medical School National TB Center
Heartland National TB Center
American Thoracic Society (ATS)
National TB Controllers Association

International

International Union Against Tuberculosis And Lung Disease (IUATLD)
Stop TB Initiative
World Health Organization (WHO)
RESULTS
USAID
Gates Foundation