The disease-stricken chief of the Hospital Authority, William Ho Shiu-wei, last night sent out an open letter from his hospital bed as a second top official was diagnosed with atypical pneumonia. Dr Ho, 44, who was admitted to the Queen Mary Hospital on Sunday, wrote in his letter yesterday that he was deeply impressed by the 'world-class'' medical service provided by his fellow Hospital Authority staff. His letter came as his colleague Fung Hong, the chief executive of the Prince of Wales Hospital, site of the worst outbreak of the virus, developed atypical pneumonia symptoms. Dr Fung, 45, who is also the chief executive of the New Territories East hospital cluster, was admitted to the Prince of Wales Hospital on Thursday after he developed fever and other atypical pneumonia symptoms. A Hospital Authority statement yesterday said Dr Fung was in a stable condition. In his letter, Dr Ho wrote: 'Under the care of my public hospital colleagues and their outstanding clinical skills, I am very relieved and impressed by the world-class medical services provided by the Hospital Authority. 'I am sure all other patients also enjoy such a quality service. In the pneumonia incident, the staff of all hospitals have gained respect and praise from different sectors and all people in Hong Kong for their highly professional performance and spirit.' The Hospital Authority chief said he had been told to stay in hospital for two more weeks. Dr Ho claimed he had taken all precautions, including preventive personal hygiene such as washing hands regularly, before he was struck down with the virus. 'It is difficult to conclude how I contracted the virus when I visited high-risk areas such as the observation ward and the intensive care unit at the Prince of Wales Hospital,' he wrote. 'At that moment, before I came down with the disease, I felt my colleagues at the Prince of Wales Hospital felt worried, and even had the feeling of being deserted. So I hoped it would encourage them when I showed up at the hospital.' Meanwhile, the Hospital Authority announced yesterday Princess Margaret Hospital will receive patients with symptoms of atypical pneumonia referred from other hospitals. A spokesman for the authority said visitors would not be allowed in areas where atypical pneumonia patients were being treated. The authority also appealed to the general public not to visit hospitals. As a result of the arrangements, accident and emergency services at the Princess Margaret Hospital were suspended at midnight last night.