A patients' rights group is trying to contact parents whose babies are suffering from an intestinal illness in Queen Mary Hospital with a view to possibly suing the Hospital Authority. Tim Pang Hung-cheong, a spokesman for the Patients' Rights Association, said the authority owed the families an explanation about the cause of the outbreak. 'With more pressure from the affected families, we hope the hospital will give a clear and thorough explanation to the parents. Moreover, it also needs to tell the public why this happened so that similar incidents can be prevented in the future.' The Hospital Authority said yesterday the outbreak at Queen Mary's neonatal intensive-care ward had not been repeated at any of its other facilities. This month's outbreak affected eight premature babies, of which one has died. The other seven babies have been treated in an isolation unit and all are in a stable condition. The authority's chief executive, William Ho Shiu-wei, said yesterday the cause of the outbreak remained unclear. 'Very often we are unable to identify the cause because it's not a conventional type of infectious disease where the illness is spread from one patient to another,' he said. 'There may be other reasons [for the infection] because the premature babies have other deficiencies. Usually, there is more than one single reason that causes the infection. Our staff are looking into the matter, but there's no guarantee we will identify the cause.' Dr Ho said the authority had contacted the infected babies' parents but had not said whether the hospital would apologise. However, Mr Pang said even though intestinal illnesses were common among premature babies, there was still a possibility of negligence.