SINGAPORE - One of the children exposed to the nurse at the National University Hospital (NUH) who has tuberculosis (TB) has been found to have the bug.

The boy, who is four months old now, was in Ward 47 where the nurse worked, from Aug 23 to Sept 5.

The hospital is recalling 178 paediatric patients who had been cared for by the nurse before she discovered she had the disease.

The nurse was diagnosed with TB at the end of last month, and immediately informed the hospital, which swung into action to identify and screen patients who might have caught the bug from her.

The boy is one of more than 80 who have been screened so far, and the only one found to harbour the bacteria.

Associate Professor Daniel Goh, head of paediatrics at NUH, had said there is no urgency of getting all the children screened as the bug does not translate into full blown TB the moment someone gets it.

This is the case with the boy, who was found to have latent TB. This means he has the bacteria in his system, but does not have the disease.

Treatment for latent TB has a greater than 90 per cent chance of preventing the disease. Treatment is also very good for people with full blown TB.

A spokesman for the hospital said treatment has started for the infant for his latent TB.

TB is transmitted through airborne droplets and usually requires significant contact with an infected person.

It is found in the community here and so far this year, 1,252 people have been diagnosed.

Symptoms of TB include persistent cough, fever, fatigue, chills, loss of appetite and weight loss.

However, people with latent TB do not have the disease and have no symptoms.