Tuberculosis is an airborne disease ("Mystery over how 6 patients ended up with same TB strain"; June 16).

Many people cough or sneeze in public with their mouths wide open, making no attempt whatsoever to cover their mouths or turn away from passers-by.

Such uncovered, open-mouth coughing or sneezing in public places such as MRT trains, taxi stands, coffee shops, shopping malls or supermarkets can spread infectious respiratory diseases such as TB.

Given Singapore's history with the severe acute respiratory syndrome, which resulted in 238 people being infected and 33 deaths here, it is incredible that such uncovered, open-mouth coughing continues without any campaign to educate the public about the dangers or to encourage people to cover their mouths and turn away.

There have been many occasions - in malls and on trains - when people coughed in my direction, or in the direction of people near them, without covering their mouths. This is how infectious diseases such as TB can be spread.

It is high time we addressed this public health issue.

Eric J. Brooks