Advisory Council on Food and Environmental Hygiene

A Report on the Recent Avian Flu Incident

Purpose

This paper provides a report on the avian flu incident that occurred in May-June 2001 and the improvement measures that the Government has and will put into place to minimize the risk of recurrence.

The Incident

2. At the last meeting of the Advisory Council on Food and Environmental Hygiene held on 17 May 2001, Members were informed of the action taken by the Government on 16 May 2001 to close and disinfect the poultry stalls of the Yeung Uk Road Market, Fa Yuen Street Market and Smithfield Market and destroy the live poultry there to prevent the spread of H5N1 virus amongst the chicken population. The action was based on the fact that there were signs of re-assortment of the goose-type H5N1 virus isolated from samples collected from the Yeung Uk Road Market and Fa Yuen Street Market, that there was an extraordinary number of chicken deaths in these markets, and that the chickens had died of avian flu as revealed by post-mortem examinations.

3. On 17 May 2001, an extraordinary number of chicken deaths was reported in the Tai Shing Market at Wong Tai Sin. The same happened in the Pei Ho Street Market at Shumshuipo on 18 May 2001. Post mortem of dead chickens from these two markets and from five other markets found that avian flu was the cause of death.

4. Although there was no evidence that this H5N1 virus would affect human health, we could not rule out the possibility that the virus would further re-assort and develop into a strain of virus that could affect human health. We therefore decided on 18 May to close all retail outlets of live poultry and thoroughly disinfect and cleanse the outlets. The operation was completed on 20 May.

5. Although there was no sign of infection of avian flu virus among poultry in wholesale markets and local farms, poultry in the wholesale markets and marketable poultry in local farms could not be released for sale due to the closure of all retail outlets. They would become too old for sale if kept there until the re-opening of the retail outlets. Thus, with the consent of their owners, we destroyed the poultry in the wholesale markets on 19 May and the marketable poultry in local farms between 21 May and 30 May.

6. In all, we destroyed 235 000 birds in poultry retail outlets, 66 000 birds in wholesale markets and 952 000 birds in local farms. We also seized 119 000 dressed poultry from the retail and wholesale markets.

7. During the closure period of retail poultry outlets, thorough cleansing and disinfection of all these outlets were carried out. We also placed sentinel chickens in 13 markets to test for the presence of avian flu virus. These chickens all tested negative for the virus. We reopened the Cheung Sha Wan Temporary Wholesale Poultry Market on 15 June and the supply of imported and local live chickens resumed on that day. The sale of live poultry in retail outlets resumed on 16 June.

8. Experts in the Special Investigation Group on Influenza agreed that the recent avian flu incident was caused by infection of genetically re-assorted H5N1 goose-type viruses amongst chickens. They were of the view that the virus could have infected chickens through a number of means and it was not possible to identify one single route through which the virus had passed to chickens.

Improvement Measures

9. As the H5N1 virus could have infected chickens by different means, we have critically examined the entire supply flow of live poultry and reviewed the whole H5N1 prevention and surveillance programme. We have devised a series of improvement measures as elaborated in the paragraphs below.

(a) Handling of ducks and geese

10. Ducks and geese are natural carriers of avian flu viruses. The recent avian flu incident was caused by a goose-type H5N1 virus that showed signs of re-assortment. We have therefore put in place the following measures to ensure complete segregation of live ducks and geese from live chickens -

  1. Live geese have been transported directly by boat to the Western Wholesale Market for destroy since 1998. Starting from 10 June 2001, live ducks are transported to Hong Kong by dedicated vehicles. At the same time, measures have been put in place to ensure that cages used for the transportation of ducks would not be used for the transportation of chickens; and

  2. We are amending the subsidiary legislation of the Public Health and Municipal Services Ordinance (Cap 132) to require separate packing of carcass and offal of ducks and geese for sale at retail outlets.

(b) Rest Day for Cleansing

11. To break the cycle of any avian flu viruses that might exist, we decided to specify a rest day every month - the 25th day of the month - for cleansing poultry wholesale markets and retail outlets. On the rest days, traders should suspend the sale of live poultry and vacate their stalls for thorough cleansing and disinfection. The first "rest day for cleansing" following the reopening of retail outlets will fall on 25 July. We have agreed with the trade over the other rest days in the coming six months.

12. Before the recent avian flu incident, the Cheung Sha Wan Temporary Wholesale Poultry Market already had three rest days per month. This arrangement will continue. As regards the Western Wholesale Market for geese and ducks, we shall also specify a "rest day for cleansing" every month to carry out thorough cleansing.

(c) Measures to Improve the Hygiene Condition of Markets

13. Prior to the reopening of retail outlets, we had taken the following actions to improve the overall hygiene condition of markets -

  1. Poultry stalls operators had completed three rounds of cleansing and disinfection under the supervision of the Food and Environmental Hygiene Department (FEHD). The hygiene condition of the stalls was found satisfactory;

  2. During the closure period, the ventilation systems of all the poultry stalls in markets were thoroughly cleansed and some scalding rooms had additional exhaust fans installed. Some small-scale improvement works at poultry stalls and scalding rooms, including the replacement and repairing of damaged floor tiles, wall tiles and grating covers of culverts, were also completed; and

  3. FEHD organised hygiene seminars to remind workers of poultry stalls the proper ways of delivering, storing, scalding and handling live poultry, as well as the hygiene standard of poultry stalls.

14. We have also formulated new conditions for tenancy agreement/ licence and new hygiene guidelines for retail poultry outlets. These include -

  1. specifying the number of chickens that can be kept in each cage in accordance with the density recommended by veterinary surgeons;

  2. requiring stall operators to avoid stacking up too many cages at their stalls;

  3. requiring stall operators to report the number of chicken deaths to FEHD every day;

  4. requiring stall operators to use handcarts with bottom plates in moving poultry and cages to keep market passageways clean; and

  5. requiring cages for chickens to be sent back to the wholesale market for cleansing soon after the chickens are unloaded.

In addition to the existing staff stationed in markets, FEHD will deploy more Health Inspectors to inspect markets to ensure compliance with the conditions. The Health Inspectors will also supervise the thorough cleansing by stall operators on rest days to maintain the hygiene standard of markets.

(d) Wholesale Markets

15. Before the recent avian flu incident, cage cleansing service was provided by trade associations and monitored by AFCD at the Cheung Sha Wan Temporary Wholesale Poultry Market. Upon the reopening of the Wholesale Market, AFCD has engaged a contractor to provide cage cleansing service so that the Department can directly supervise the cleansing process.

(e) Farms

16. Although we did not find avian flu virus in local farms in the recent incident, we will step up publicity to inform farmers of the importance of preventing bird diseases and maintaining the hygiene standard of farms. We will also amend livestock keeping licensing conditions to prohibit the return of unsold chickens from markets to farms. We will consult farmers on the new licensing condition with a view to bringing it into effect as soon as possible.

(f) Avian Flu Surveillance System

17. We have conducted a review after the incident to identify areas where this can be enhanced. We have decided to -

  1. increase the number of blood samples taken from chickens at the border;

  2. take additional blood samples, from chickens in wholesale markets for testing;

  3. take swabs from dead chickens at wholesale markets for testing on a regular basis;

  4. take swabs from dead chickens at retail markets for testing on a regular basis; and

  5. enhance the reporting mechanism on death of chickens in markets and if any increase in number of deaths occurs to ensure samples are collected for virus detection.

Conclusion

18. We believe that the implementation of the above measures will reduce the risk of H5 viruses becoming established in markets and will improve our ability to monitor these viruses effectively.

19. Members are invited to note this paper for information.

Environment and Food Bureau
June 2001

 

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