There are about 10 million cases of active TB in the world every year and about 2 million deaths, with much of this activity being in sub-Saharan Africa and other low-income areas.
About 1/3 of the world's people have been infected with the TB bacillus - that is about 2 Billion (with a B) people!!!! But, being "infected" (having the germ in one's body) does not necessarily mean active "disease", thankfully!!
TB is transmitted when an infected person coughs or sneezes. When the bacteria is inhaled, there are several possible outcomes. It can be immediately cleared by the immune system or, on the other hand, can cause immediate active disease. Or, as happens most often, the bacteria can be contained in the lungs by the immune system and lay dormant, also called being latent or asleep. Of those with dormant/latent TB, only 5-10% go on to develop active TB. Anything that depresses the immune system can increase the risk of developing active disease - HIV, malnutrition, poverty, cancer, old age, use of steroids to name a few. ....any new TB patient is routinely tested to see if they are HIV positive since TB and HIV are so often associated.
When your doctors in a developed country like the US do a TB skin test, they are looking to see if you have a dormant infection (ie you are "infected but not diseased"). If you do, in most cases, 6-9 months of an anti-TB med is prescribed to limit the risk of your developing active disease.
But things are different in developing countries like Niger, where the public health infrastructure is much less developed and primary attention is given to treating the many active cases. Active TB patients often present with chronic cough, sputum that can be blood-tinged, fever, sweats, and wasting (in the old days, TB was called "consumption"). An x-ray may show cavities or abnormal infiltrates. There can be disease in virtually any organ - fluid around the heart or in the abdomen, lymph node involvement in the neck ("scrofula"), meningitis, or a spine with collapse of vertebral bones and pain.
(Side note: In developing countries with a moderate to high incidence of TB like Niger, the World Health Organization advises that all newborns receive a vaccination with BCG, which is a "live attenuated vaccine" of a bacteria related to TB. This vaccination confers about 80% protection for 15 years or so and then the effect wanes. Revaccination is not very effective nor is vaccination of adults.)
When we see a patient here with any of the symptoms listed or an abnormal x-ray, we think of TB. Usually, we request that several sputum samples be stained and searched for the TB bacteria. In some cases, though, especially if clinical suspicion is high, we just go ahead and begin treatment. Treatment is 4 drugs for 2 months followed by 2 drugs for 4 months. The drugs are provided free by the government and there is a TB officer here at Galmi who monitors the patients and gives a month of drugs at a time. In addition to curing the patient and restoring them to well being, a major public health goal is to prevent transmission to other people.
...This middle aged woman complained of chronic cough, fever, and weight loss. She appeared very wasted and concern was raised for HIV but the test was negative. Her chest x ray showed a large right lung infiltrate and lesser infiltrate on the left. Her sputum samples returned positive for TB.
...this was a young man who came in critically ill with extreme shortness of breath. He had no breath sounds on the left side of his chest and his chest x-ray showed a marked shift of the heart to the right side of his chest. The left side of his chest showed that the cause was contained air and pus under pressure, a "tension pyo-pneumothorax". I called the surgeons who saw him urgently and placed a chest tube which decompressed his chest and gave immediate relief. In a case like this, TB is the cause until proven otherwise and a 4-drug regimen will be started.
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