13 August 2004
Dear Doctors,
H5 influenza infection in Vietnam
We would like to draw your attention to the three fatal cases due to H5 influenza infection in Vietnam reported on 12 August 2004 by WHO. The three cases were among a group of patients admitted to hospitals in Vietnam between 19 July and 8 August. Two of these fatal cases occurred in the northern Ha Tay Province. The third one was in the southern province of Hau Giang. These came after the reports that new outbreaks have been occurring in poultry populations in Vietnam since July this year. Further details can be found at the WHO website: http://www.who.int/csr/don/2004_08_12/en/ .
Avian influenza (A/H5N1) has been known to infect humans in 1997 while 18 cases including 6 deaths were identified in Hong Kong. From January to March 2004, WHO recorded 34 laboratory-confirmed human infections, including 23 fatal cases, of influenza A (H5N1) in Vietnam and Thailand. These human cases coincided with the period when there were outbreaks of highly pathogenic avian influenza found in the poultry population. So far, the available investigations suggested that the main mode of transmission is from bird-to-man. Man-to-man transmission remains inefficient and rare.
In view of the human cases of avian influenza H5 in Vietnam, you may wish to consider this as a differential diagnosis for patients with acute respiratory illness, characterized by fever (temperature >38°C) and cough and/or sore throat, and have visited poultry farms in Vietnam. Please also advise patients who are travelling : (a) to avoid contact with live poultry/birds; (b) to wash hands thoroughly after contact with live poultry/birds, and (c) to consult a doctor if they develop symptoms of influenza during or after travelling.
Influenza A (H5) has been a statutorily notifiable disease in Hong Kong since 30 January 2004. (Case definitions and reporting criteria as attached) Please send your notification on cases meeting the reporting criteria to the Central Notification Office of Centre for Health Protection at Fax: 24772770 and Tel: 24772772 .
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Yours sincerely,
(Dr Teresa CHOI)
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