A Disease of Poverty: Tuberculosis

Tubercolosis, also known as MTB or TB, is an infectious disease which is often associated with poverty. It is spread through the air when people who have active MTB infection cough, sneeze, or spit.

Causes

The cause of TB is primarily a small aerobic non-motile bacillus. It divides every 16 to 20 hours, an extremely slow rate compared with other bacteria, which usually divide in less than an hour. MTB can withstand weak disinfectants and survive in a dry state for weeks. In nature, the bacterium can grow only within the cells of a host organism, but tuberculosis can be cultured in vitro.

There are various risk factors which come into play:

• Persons with silicosis have an approximately 30-fold greater risk for developing TB. Possible indoor sources of silica include concrete, cement and paint.
• Persons with diabetes mellitus have a risk for developing active TB that is two to four times greater than persons without diabetes mellitus, and this risk is likely greater in persons with insulin-dependent or poorly controlled diabetes. The correlation between diabetes mellitus and TB is concerning for public health because it shows a distinct connection between a contagious disease and a chronic disease.
• Low body weight is associated with risk of tuberculosis. A body mass index (BMI) below 18.5 increases the risk by 2—3 times. On the other hand, an increase in body weight lowers the risk.
• Another condition that increases the risk is the sharing of needles among IV drug users.

Symptoms
Symptoms include chest pain, coughing up blood, and a productive, prolonged cough for more than three weeks. Systemic symptoms include fever, chills, night sweats, appetite loss, weight loss, pallor, and fatigue.


Treatments
Treatment for TB uses antibiotics to kill the bacteria. Effective TB treatment is difficult, due to the unusual structure and chemical composition of the mycobacterial cell wall, which makes many antibiotics ineffective and hinders the entry of drugs. The two antibiotics most commonly used are isoniazid and rifampicin.TB can either be latent or active. Latent TB treatment usually uses a single antibiotic, while active TB disease is best treated with combinations of several antibiotics, to reduce the risk of the bacteria developing antibiotic resistance. People with latent infections are treated to prevent them from progressing to active TB disease later in life.