WhyItMatters

TB outbreak at Ang Mo Kio a mystery

Two more Ang Mo Kio residents may have the same strain of tuberculosis (TB) as the six who were identified earlier.

Normally, this would be no cause for alarm since TB is endemic here. Last year, more than 1,400 people were diagnosed with TB and, so far this year, more than 700 people have discovered that they have the bacterial infection, which attacks the lungs.

What makes this outbreak different, and worrying, is the way it has spread to these people.

 

TB is spread through tiny water droplets in the air - such as when a person sneezes or coughs. While contagious, TB does not spread easily, since it usually takes long-term exposure for it to take root.

Of the original six people who had the same strain of TB, three did not know the rest or one another, so the question is: How did they catch the disease?

It is not known if the latest two come from any of the original four households. If they don't, and also have not interacted with the rest, then the mystery deepens. Hopefully, all eight people caught the disease from one source with whom they have had long-term interaction. If that's the case, then there is nothing to worry about, since it then becomes "normal". Otherwise, we are into uncharted waters.

Is this TB strain so virulent it can spread through casual contact - such as by sharing a lift ride where one of the passengers coughs? Or does it spread through means other than water droplets in the air?

If either of the above is true, then has the strain of TB spread beyond Ang Mo Kio? How do people protect themselves when there is no way to identify people who are infectious?

To make matters worse, this particular strain is multi-drug resistant, so it is more expensive and difficult to treat. The only thing that we can do to prevent the further spread of the disease is to practise good hygiene: Cover our mouths when we sneeze or cough so whatever germs we have are not spread to others.

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A version of this article appeared in the print edition of The Straits Times on July 06, 2016, with the headline 'TB outbreak mystery'. Print Edition | Subscribe