Purpose
This paper sets out the preventive and contingency measures implemented/devised by the Administration and the Hospital Authority to handle a possible outbreak of avian influenza (AI) in Hong Kong.

Summary of Recent AI Cases Outside Hong Kong

2. Since early December 2003, a total of ten countries or places in Asia have reported outbreaks of AI. These countries and places include South Korea, Japan, Vietnam, Thailand, Taiwan, Cambodia, the Mainland, Laos, Indonesia and Pakistan. We have taken immediate steps to suspend temporarily the processing of applications for importation of live birds and poultry meat from the infected places. Such suspension is in line with the recommendations of the Office International des Epizooties (OIE), which is the international authority on animal heath and disease, in dealing with an outbreak situation and also has taken into consideration the evolving situation in the region.
   
3. On 7 February 2004, there were media reports of an outbreak of AI in a poultry farm in the State of Delaware in the United States. According to the available information, the farm was infected by H7 AI virus, which was thought to be a low pathogenic AI. As a precautionary measure, we temporarily suspended the processing of applications for importation of live birds and poultry meat from the State of Delaware, pending further confirmation from the relevant authorities on the pathogenicity of the AI virus.
   
4. As of 10 February 2004, a total of 23 cases of H5N1 human infections have been confirmed in Thailand and Vietnam, of whom 18 have died.

Measures to Prevent the Recurrence of AI Outbreaks in Hong Kong

5. Hong Kong has experienced four H5N1 AI outbreaks in poultry since 1997. Throughout the years, we have put in place a series of preventive measures to guard against possible outbreaks targeting in particular the sources of the virus and potential carriers, i.e. live poultry and wild birds. These measures include:

• Vaccination – Following a trial scheme launched from late 2002 to early 2003, we have introduced a vaccination programme in June 2003 to cover all chicken farms. An agreement has also been reached with the Mainland to vaccinate all chickens for export to Hong Kong. From 15 January 2004, all imported and local chickens in the market have to be vaccinated to ensure their immunity status is maintained at a satisfactory level.
  
• Regulation of local farms including tightened biosecurity measures – In view of possible transmission from wild birds and migratory birds, the installation of bird-proof facilities is required. To detect if local farms are infected, sentinel chickens (i.e. unvaccinated chickens) are placed in each batch of vaccinated chickens. Through monitoring the health conditions of the sentinels together with testing on antibody level of vaccinated chickens, the effectiveness of the vaccine in protecting the chickens can be constantly checked.
  
• Import control – All imported chickens from the Mainland must come from registered farms recognised by the Mainland authority. A health certificate must accompany each consignment of imported chickens. Other import control measures include inspection of every consignment of imported chickens, testing of antibody level of imported chickens, dead and sick bird monitoring and random screening tests of infection as appropriate.
  
• Segregation policy – As waterfowls are natural carriers of AI viruses, all waterfowls in Hong Kong must be centrally slaughtered and no live waterfowls are allowed to be sold in retail outlets. In addition, we require that waterfowl’s offal be separately and individually packed to prevent cross-contamination. To prevent the mixing of different types of AI viruses that may result in reassortment into deadly viruses, a segregation policy based on risk assessment has been implemented. All live quails must be segregated from live chickens from farms to retail outlets. No live quails are sold in our retail outlets.
  
• Market rest days – At the wholesale and retail levels, we have market rest days to break the virus cycle and reduce the viral load there, if any. There are four rest days for the wholesalers and two matching rest days for the retailers. Trading activities must cease on the rest days and all live poultry in the retail outlet must be slaughtered. The premises must be thoroughly cleansed and disinfected.
  
• Hygiene requirements on wholesale market and retail outlets – We have imposed stringent hygiene requirements on these premises. In addition, poultry retailers are required to surrender all live poultry for disposal on detection of even one dead bird with H5 virus isolated. The concerned outlets should then be thoroughly cleansed and disinfected.
  
• Surveillance – A comprehensive surveillance programme on both human influenza and avian influenza have been put in place to monitor human influenza activity and detect the presence of all types of avian influenza viruses in the environment. The human surveillance programme covers a network of clinics, hospitals and laboratories in the public and private sectors. Since 1998, an avian influenza surveillance programme, targeting at poultry at all levels from farms, imports, wholesale to retail outlets, has been implemented for early detection of abnormalities. This programme has been extended in 2003 to cover wild birds, waterfowls in recreational parks and pet birds available for sale in the market.