INDEPTH: HEALTH
Tuberculosis: Anatomy of a killer
CBC News Online | Updated March 23, 2005
Ever heard of White Plague? What about Pott's disease? Lupus Vulgaris? King's evil? No? OK then, surely you've heard of consumption. All of these diseases are actually the same disease, better known today as tuberculosis or TB for short.
TB bacterium, from lung.ca
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Tuberculosis is a disease caused by a germ called Mycobacterium tuberculosis. What makes TB such a health threat is that it is not only contagious, it spreads through the air. So when an infected person coughs, sneezes, spits or even just talks, they're spreading the bacteria. Other people become infected when they breathe in the now air-borne bacteria.
This is why the World Health Organization reports that about one per cent of the world's population becomes newly infected each year. Once infected, the bacteria can lie dormant inside the body for years.
Most people don't even realize they were infected. They don't feel sick and they don't show any symptoms. In fact, most people who get infected, about 90 to 95 per cent, never get sick.
It's the other five to 10 per cent who have to worry. These are people who have weaker-than-normal immune system, such as children, the elderly or people with immune deficiency diseases like HIV.
When the bacteria become active, they can attack any part of the body although they commonly go for the lungs. Once there, the bacteria begin to grow and move through the blood to other parts of the body such as the kidney, spine and brain.
Tuberculosis in the lungs may cause a bad cough that lasts longer than two weeks, chest pain and make the patient cough up of blood and phlegm. Other symptoms include weight loss, fatigue, a lack of appetite, chills, and fever.
Tuberculosis has been around for a long time. Tissue samples from grave sites and the examination of an Egyptian mummy suggest people were infected by tuberculosis as far back as 5,400 years ago, but scientists believe the bacteria is probably three times as old.
Documentation of TB goes back to the Ancient Greeks who identified what they called "phthisis" as the most widespread disease of the time, one that was almost always fatal.
But it wasn't until 1546 that the first book to explain that TB was contagious was written. And it took almost another 200 years before scientists realized that it didn't only attack people who had certain physical attributes.
Then in 1882, a German bacteriologist named Robert Koch made an important discovery. He identified the tuberculosis bacillus, the bacteria at the root of the disease. Koch's work won him the Nobel Prize in physiology or medicine in 1905.
Luckily, the research over the years has helped in the development of effective treatments during the 20th century. Now people with active tuberculosis can be treated and cured if medical help is accessible and infected people who aren't sick can take medicine to avoid developing TB disease.
1942 fluograph (X-Ray)
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People who think they may have caught TB can get a TB skin test, in which a health care worker injects a small amount of testing fluid just under the skin on an arm. After a couple of days, the spot where the needle was injected is examined for a positive or negative reaction to the test.
If the person tests positive, usually meaning he or she has TB, the person can get medicine that will kill the bacteria before they become active. One such drug is called "isoniazid" which most people usually have to take for at least six months.
There is also a vaccine called BCG(COMMA)which is often used to prevent children from getting tuberculosis, although it's not always effective.
People who develop a TB disease can almost always be cured provided the proper medical treatment is available. Unfortunately this is not the case in many countries where TB is killing thousands.
Overall, Canada is doing pretty well in its fight against tuberculosis. The rate of the disease has dropped from about 120 cases per 100,000 people in the 1940s to 5.2 cases per 100,000 people in 2002.
Of the 1,634 cases reported in 2002, 115 were reported to have died, but only 68 of the deaths were linked to TB.
Not bad for a population of 30 million but not quite the elimination of the disease that was predicted to be achieved by the year 2000.
The Canadian Lung Association (formerly the Canadian Tuberculosis Association) says there are three reasons why Canada hasn't managed to shake the disease. The first is that because tuberculosis bacterium is a living organism, it is in a constant fight to survive in its changing environment. This is why new strains of the bacteria adapt to resist drugs.
The second reason is that, due to the nature of the Canada's population - with people immigrating from all of the world - the disease is brought over from countries where drug treatments for TB are not readily available.
And lastly, there exists a reservoir for TB among people considered "high risk" for infection - those with weak immune systems or living in communities that lack the proper health services.
The World Health Organization announced its Stop TB initiative in 2000, with the goal of reducing tuberculosis deaths by 50 per cent by 2010.
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