How Long Does Tuberculosis Last?

Tuberculosis is a disease caused by mycobacterium. The bacteria can infect any part of the body, including the bones, joints, skin, lymph nodes and nervous system; however, it most commonly infects the lungs. Tuberculosis spreads easily from person to person, but not everyone who inhales the bacteria will actually develop the disease. Since the bacteria have the ability to remain latent in the body, the infection can last a lifetime.

Cause

• There are three main types of tubercle bacteria that can infect humans. Mycobacterium tuberculosis is the most common and it is spread human to human through contact. There is also a bovine strain called mycobacterium bovis that is spread to humans through infected cattle. Infections caused by this strain are very rare since the introduction of pasteurization and strict regulations on farmers. The third strain is an avian, or bird, strain called mycobacterium avis, which can spread from infected birds to humans.
  The mycobacterium can live outside a host, in the air and dust, for quite some time. Since the infection is spread through inhalation, this makes it even more infectious.

Diagnosis

• The best way to diagnose if a patient has been exposed to tuberculosis is through a tuberculin skin test, also known as a TB test. Patients that have the bacteria present in their body will test positive. This confirms infection, and to test for disease an X-ray can be taken. Since tuberculosis is most commonly an infection of the lungs, an X-ray of the lungs will reveal if the disease is present.

Tuberculosis Infection

• Most people who come into contact with the bacteria will become infected. Some of those infected will develop the disease soon after infection, however, in most their immune system will fight the bacteria, causing them to stop growing and become inactive. Those with tuberculosis infection will test positive on the TB skin test, but will not have symptoms, do not feel sick and cannot spread the disease to others. Those infected should take preventive therapy as soon as they learn of the infection or else they may develop the disease later in life.

Tuberculosis Disease

• Tuberculosis disease happens when the body's immune system cannot fight off the bacteria once infected. For some it develops right away, for others it can be years after infection when their immune system is compromised for some reason. Those with the disease will develop a bad cough lasting more than three weeks, feel pain in their chest and may even cough up blood or sputum. Other symptoms include fatigue, weight loss, chills, fever and night sweats. Those with the disease must undergo a rigorous course of antituberculosis drugs right away to prevent further growth of the bacteria and the possibility of promoting drug-resistant bacteria.

Treatment

• Even those infected but not suffering from the disease should take a course of antituberculosis drugs, including rifampin, pyrazinamide and ethambutol. These drugs must be taken for six to 12 months. Since many of those infected do not have the disease and therefore do not have symptoms, they choose to abandon the preventive treatment prematurely. The problem with this is that it promotes the growth of drug-resistant bacteria, because if at a later date their immune system becomes compromised, the bacteria can become active and grow, and will not respond to treatment. This drug-resistant form of tuberculosis is especially life-threatening. There is a preventative available called the BCG vaccine, which is regularly administered to children in countries where tuberculosis is still prevalent, but the vaccine is found to be effective in only about 50 percent of those treated.

Incidence

• Many in the United States believe that tuberculosis no longer presents a threat, but that is not exactly true. Tuberculosis is still prevalent in many countries and is therefore a global threat. The United States welcomes many immigrants each and every day. Since tuberculosis infection can remain dormant for an indefinite period of time there could be thousands of people allowed into the country each month that still have the potential to develop the disease, which can then be spread.