Centre for Health Protection Controller Dr Thomas Tsang says the three recent serious infections of children are not from the same source, adding chances are slim for new viruses or bacteria to develop in Hong Kong.

Dr Tsang told reporters today more tests will be conducted to find the cause of the infections, adding the centre has enhanced surveillance.

On average, 15 to 20 children aged nine or below die in Hong Kong yearly from probable infective causes. The more common manifestations include: myocarditis - inflammation and swelling of the heart muscle, usually caused by a viral infection; encephalitis - acute inflammation of the brain; pneumonia - inflammation of the lung; and septicaemia - blood poisoning. In many cases of encephalitis and myocarditis, the original cause cannot be identified.

Expecting sporadic cases to occur in Hong Kong Dr Tsang said the centre will closely monitor the situation.

Parents should pay special attention to their children's personal hygiene and seek treatment if they develop symptoms such as persistent fever, vomiting, cramps and unconsciousness.