January 26, 2000
The influenza surveillance system of the Department of Health (DH) has detected the circulation of another type of influenza virus, H1N1 (New Caledonia), in Hong Kong.
Announcing the news at a media briefing, Consultant (Community Medicine), Dr K.H. Mak, said however that despite the detection, the predominant strain was Sydney flu virus (H3N2).
"The outbreaks of influenza due to New Caledonia strain were reported in New Caledonia during the period May to June,1999. According to reports available, the strain causes relatively mild illness. Moreover, H1N1 viruses have been circulated in Hong Kong since 1977, people previously exposed would have some protection against the present H1N1 viruses. Hence, while there may be further cases of H1N1 (New Caledonia), there is no need for undue panic." Dr Mak said.
He added that DH would continue to monitor the activity of the disease locally as well as in other countries.
Dr Mak said that to prevent influenza, it is important to:
"The young, the elderly and those suffering from chronic diseases should seek medical advice promptly should they develop influenza-like symptoms"
Dr Mak said that influenza vaccine is recommended for people at increased risk of influenza complications, such as residents of institutions for the elderly.
DH had completed its annual influenza vaccination for residents of homes for the elderly where a good coverage rate of more than 80 per cent was attained.
The influenza vaccine currently in use in Hong Kong does offer some cross-protection to the present strain of H1N1 virus, Dr Mak said.
Reviewing the trend of infectious diseases last year, Dr Mak said that the number notified to DH increased to 20,398 in 1999 from 9,825 in the preceding year. The increase was largely due to chickenpox (10,895) which became notifiable in February, 1999.
Dr Mak said that there has been a decline however in food borne illnesses, in particular bacillary dysentery, food poisoning and cholera.
"This was partly due to a natural fall after the higher level of foodborne disease activities detected in the previous year and partly to our efforts in promoting food, personal and environmental hygiene," he said.
For vaccine preventable diseases, Hong Kong remained free from poliomyelitis and diphtheria. Notifications of measles, mumps, rubella, hepatitis B and whooping cough were on the low side, thanks to the childhood immunization programme.
Increase was however noted in vector borne diseases, particularly typhus fever.
Stressing the need to heighten surveillance and to further strengthen the vector control programme, Dr Mak appealed to the public to keep their home and work environment free of rodents and mosquitoes and to apply insect repellants to exposed body parts or wear long-sleeved clothing and trousers while carrying out outdoor activities.
He went on to say that in the latter part of 1999, Norwalk-like virus infection had caused several outbreaks in institutions. The major mode of transmission was through aerosal and person-to-person spread while food borne mechanism was responsible in the few cases.
"DH has issued guidelines to kindergartens and nurseries on how to handle infectious diseases in such settings, in particular, to dispose of vomits properly and disinfect contaminated surfaces.
"We should keep up our efforts and continue to be on the alert. We will work with various parties to promote food and environmental hygiene, strengthen our vector control program as well as our monitoring of other infectious diseases like influenza, enterovirus infection and antibiotic resistance pattern through the sentinel surveillance system."