April 8, 1999
The Government Virus Unit of Hong Kong Department of Health (DH) had isolated, in collaboration with local and international experts, a new strain of influenza A virus (H9N2) from two patients recently in April 1999.
The two patients were girls aged one and four. The four-year-old girl had history of asthma and eczema on regular steroid inhalation and salbutamol inhalation. The one-year-old girl had history of failure to thrive still under investigation. Both of them were hospitalised in early March 1999 due to influenza-like illnesses with fever 39 - 40 oC. Their initial clinical presentations were similar to those of typical influenza, with fever of acute onset, sore throat, vomiting and headache. Both of them had no complication and recovered fully.
Influenza A (H9N2) viruses have been isolated in birds for many years. They may cause very mild illness in birds like turkey, chicken and duck. They were isolated for the first time in humans in Hong Kong. The Department of Health is working closely with local and overseas experts to ascertain the mode of transmission of the virus and determine its public health impact.
The information gathered so far suggests that influenza A (H9N2) has similar clinical presentation as other influenza viruses. The appropriate management should consist of adequate rest, fluid replacement and antipyretic as necessary. Aspirin should be avoided in children. If there are signs of complications such as pneumonia, the patient should be hospitalised. The H9N2 virus is sensitive to amantadine and rimantadine.
Appropriate counselling on prevention of influenza should be given to patients and members of general public. Important messages include a balanced diet, regular exercise, adequate rest to maintain body immunity and no smoking. Observation of good personal hygiene and maintaining good ventilation are also useful. Members of the public are also advised to wash their hands after handling poultry or the birds' excreta.