Tuberculosis (TB) - Opportunistic Infections
Tuberculosis (TB) is a serious infection that kills more HIV positive people than any other condition. It accounts for around 15% of AIDS deaths worldwide.
It’s a highly contagious disease caused by the bacteria mycobacterium tuberculosis which is spread through the air when an infected person coughs or sneezes. It can affect any part of the body but usually targets the lungs.
TB doesn’t seem too serious when you consider that an estimated one third of the world’s population is infected with it. Generally a healthy immune system will stop it from becoming “active” and spreading – some people can carry inactive TB throughout their entire lifetime without even knowing about it.
But when someone is infected with the HIV virus their immune system is knocked for six. If they are a TB carrier the immune system is defenseless against it and the bacteria grows and becomes active. This is known as reactive TB and accounts for the majority of cases in people with HIV.
Primary TB occurs in people who have not previously carried the infection.
Tuberculosis and HIV are not a good combination. It’s a very aggressive infection and because of this can make the HIV virus multiple quicker, speeding up the deterioration of the body’s vital immune system.
The number of TB cases worldwide is increasing because of HIV. In the United States 40 times as many people with HIV have TB than those without the virus.
In sub-Saharan Africa (home to the majority of the world’s HIV cases) around 350 people in every 100,000 have tuberculosis. In South East Asia there were three million new cases reported in 2002.
Symptoms of the active disease include a bad cough, bringing up blood, chest pain, general weakness and tiredness, weight loss, sweating, fever and loss of appetite.
It’s usually diagnosed by injecting a protein found in the bacteria into the arm. If the arm goes red then a person is usually infected.
The good thing is it can be cured in about 90% of cases provided it’s diagnosed early enough and the correct treatment is started promptly. In someone with HIV tuberculosis can prove fatal if treatment is delayed.
Inactive TB has no symptoms but is usually treated with the drug isoniazid for at least six months. This drug can also be used as a preventative medication to ward off the infection in people with a severely depressed immune system.
Active Tuberculosis is more difficult to treat because there are a lot of bacteria to be destroyed. A combination of antibiotics is normally used as the bacteria can become resistant to one antibiotic if it’s used in isolation. Again this usually takes about six months.
Worryingly there is a form of the illness called multi drug resistant TB (MDR-TB) in which the bacteria are resistant to more than one drug. It’s a serious problem because it’s a case of trial and error to discover the right combination of effective drugs. More and more case of MDR-TB are now being seen – 79% of these are regarded as “super strains” which don’t respond to three out of the four drugs used to treat tuberculosis.