Approximately one-third of the world's population is infected with the bacteria - Mycobacterium tuberculosis - that causes tuberculosis.
Although the bacteria is easily spread from person to person, normally through droplet nuclei expelled into the air through coughing, only a small percentage of these people (about eight million each year) will develop active tuberculosis.
This is because most healthy immune systems are able to fight the bacteria that causes the disease. In fact, most people infected with the bacteria will never get sick and will remain unaware that they have latent (or inactive) tuberculosis throughout their lifetime.
People with HIV/AIDS have weakened immune systems and are up to 800 times more likely to contract active tuberculosis because their immune systems are weakened, according to the CDC.
The WHO estimates that the rate of progression to clinical TB is 10-30 times higher among HIV-infected people with TB.
TB is the most common opportunistic infection. In South Africa, a national survey estimated 55% of TB patients were living with HIV in 2002. The WHO estimated 61% in 2003.
Although tuberculosis usually infects the lungs, it can also be found in other organs such as the heart, brain and lymph nodes. HIV-positive people with compromised immune systems are more likely to have extra-pulmonary or non-pulmonary TB (i.e. TB outside of the lungs).
According to the NIH, out of the two billion people worldwide who have the bacteria in their body, about eight million people contract active TB per year. About three million people die from TB every year.
Treating Tuberculosis and HIV
Active tuberculosis is usually curable within six months using a combination of antibiotics. The therapy is more successful when the person takes their medication under supervision.
People who do not take their medication properly run the risk of developing Multi-Drug Resistant TB (MDR-TB), which is far more expensive and difficult to treat. Ordinary TB treatment costs about R310 (in 2002), whereas treatment for MDR-TB can cost over R20,000 per patient to treat, according to the health ministry.
People with both HIV/AIDS and TB require special treatment to combat both the conditions as some anti-HIV drugs and TB drugs interact poorly. The SA National Antiretroviral Treatment Guidelines require a regimen change if the patient is already on ART, or a delay before the commencement of antiretroviral therapy (ART) if the patient hasn't begun treatment.
