Science Interviews

Interview

Sun, 5th Apr 2009

Tackling Tuberculosis

Valerie Corfield, University of Stellenbosch

Listen Now    Download as mp3 from the show SciFest Africa Special

Valerie - Itís a rather mean, sneaky disease. Itís a bug, itís a bacterium. TB likes to get inside the body. Bodies are nice and warm, a comfortable sort of place. It likes to hang out there. It doesnít really want to do any damage but the trouble is while itís hanging out there is does cause some damage.

Mycobacterium TuberculosisMeera - What damage does it do to your body?

Valerie - Well, it needs to live. Because itís a nice warm comfortable place it tends to divide and divide and make more of itself. In doing that it needs some food and it needs space. Itís gradually pushing itself around in the lungs, pushing lung tissue out of the way Ė actually making holes in the lung.

Meera - What bacteria is it that causes this?

Valerie - Weíre talking about a bacterium called mycobacterium tuberculosis Ė MTB for short.

Meera - What are the symptoms once it kicks in?

Valerie - Coughingís the main thing. Thatís what people notice. If oneís coughed for more than two weeks one should actually go to a clinic and get tested for it. If it gets as far as coughing and spitting up blood thatís very bad news. At the same time the patient will feel tired. They might have some chest pain, night sweats maybe loss of appetite, fever. Any of those symptoms and those symptoms in combination but coughing  is the real one that will tell you thereís something wrong with your lungs.

Meera - how do people catch it?

Valerie - They catch it mostly because other people who are infected cough. When we cough we spray out a tremendous amount of little droplets. We canít even see them. The reason we have this big face here Ė Mr Coughit. Heís a model and when he coughs he sprays these fine droplets of water out into the air. If he was a person who had TB and he had TB in his lungs when he sprayed this liquid out into the air in a big cough heíd also be spraying out lots of the MTB, the germ and then other people may breathe that in, get into their lungs, settle down in their lungs and start growing.

TB PosterMeera - Can you show me Mr Coughit in action then?

Valerie - Here he goes..

<coughing sounds>

Meera - Nice sound effects there. Essentially Mr Coughit is actually a face mask with a water spray bottle attached under him. This mist is going quite far actually. Itís going about a metre away.

Valerie - I believe that really oneís coughing goes farther than that because our lungs are more powerful than this spray bottle. Really powerful cough; one could be sending it 2 metres or more through the air. People for a long way around could be infected as theyíre innocently going about their business.

Meera - How serious a disease is it? How badly can it affect your body and also is there a treatment for it?

Valerie - It depends on the person and how susceptible they are. One third of people in the world have got MTB in their body. Usually itís been encapsulated, itís in a little prison in their body and itís sleeping. Itís dormant/latent. Itís not doing any harm. Sometimes a person may be down at that particular time, their immune system is not working so well, they could be depressed, they could be under stress, they could be malnourished. In South Africa one of the problems is they may be infected with HIV. They may have AIDS which will depress their immune system. Under those circumstances the MTB bug can get a hold quicker and het going quicker. Itís not only found in the lungs. Thatís where we see the symptoms initially and thatís where the first point of treatment is but it can also spread. It can be a bone disease. It can go to the lining of the brain. It can affect the heart. It can be in the lymph nodes. When itís been diagnosed the treatment is antibiotics but unlike other antibiotics, say for a sore throat the TB bug lives for a long time in the body. Itís very hard to get those antibiotics right in there. The antibiotics have to be taken for six months.

Meera - Thatís a long time.

Valerie - Yeah thatís a long time and thatís what causes one of the problems. A person will begin to feel better from the effect of the TB, their breathing will be easier, theyíll not have the night sweats. They may begin to get their appetite back, start eating, feel a lot better. Theyíll think alright, itís gone Ė Iíll not take my medication any more.

Meera - How prevalent is it?

Valerie - In Europe in the 19th century it was quite a problem during the industrial revolution. With increasing knowledge about the bug, antibiotics, better sanitation, better living spaces the disease was conquered. Right now itís spreading again. Itís actually a problem throughout the world.

Meera - There is a vaccination available to protect people against TB.

Valerie - yeah, thereís BCG and BCGs usually given to kids quite early on in their lives. In places like South Africa itís not working very well. Itís a very old vaccination. Nothing new has been developed and I think the biggest problem now is no new antibiotics have been developed, the TB bug is acquiring a resistance.

Meera - How big a problem is it here in South Africa?

Valerie - Weíve got a big problem in South Africa. Thereís a lack of understanding with whatís going on in TB. People stop taking their medication. They stop taking it too early. Thereís still TB in their system and those TB bugs may have acquired little changes, theyíre a type of mutant. They become resistant to the antibiotics. They become resistant to the first line antibiotics. Once theyíve got resistant to more than two antibiotics theyíre called multidrug resistant. Then a new lot of antibiotics have to be brought in. The trouble is now multidrug resistant TB may acquire another mutation which makes them extremely drug resistant TB. Presently there are no antibiotics that effectively kill XTB.

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