Advisory Council on Food and Environmental Hygiene 

Avian influenza outbreaks in South Korea, Vietnam and Japan

 

Purpose

 

              This paper briefs Members of the current H5 avian influenza outbreaks in South Korea, Vietnam and Japan and the measures implemented in Hong Kong to prevent occurrence of similar outbreaks.

 

Avian influenza outbreak in South Korea

 

2.                             The Ministry of Agriculture and Forestry (MAF) of the Republic of Korea (South Korea) reported to the Office International des Epizooties (OIE) on 12 December 2003 that an H5 highly pathogenic avian influenza (HPAI) outbreak occurred in a chicken farm in Chungcheong-buk-do province, about 80 km south east of Seoul.  According to epidemiological investigation, the avian flu virus might have come from migratory birds. Many migratory birds inhabited in ponds near the index farm.

 

3.                             The strategy being used by South Korea to control the outbreak includes (i) a stamping out policy of infected farms; (ii) quarantine measures on suspected farms; and (iii) movement restrictions within 10 km radius of affected farm.  Vaccination is not adopted.

 

4.                             According to the information available to us, infection had been confirmed at 16 farms by mid January 2004, and about 16 farms were under investigation.  In one case, the disease was also found in a quail farm.  According to media reports, by end December 2003, more than 1.2 million birds had been killed to contain the disease and the MFA was planning to destroy 2.5 million chickens and 150,000 ducks to stop the outbreak. 

5.                             No human cases have been reported so far in connection with the South Korean outbreak.

 

6.                             We do not import any live poultry and birds from South Korea.  In the first ten months of 2003, Hong Kong imported about 540 tonnes of such products from South Korea, accounting for less than 1% of the total volume of poultry meat imported to Hong Kong.

 

 

Avian influenza outbreak in Vietnam

 

7.                             The Department of Animal Health of the Ministry of Agriculture and Rural Development of Vietnam reported to the OIE on 8 January 2004 that an H5 HPAI outbreak occurred in three chicken farms in the Long An Province and the Tien Giang Province, both in the Southern part of the country.  The estimated date of first infection was reported to be 27 December 2003.  It was reported that 40,000 birds had died and 30,000 birds had been destroyed. 

 

8.                             The strategy being used by Vietnam to control the outbreak includes (i) control of wildlife reservoirs of avian influenza viruses; (ii) quarantine restrictions; (iii) movement control of poultry from the affected provinces; (iv) destruction and disposal of dead and affected birds; and (v) screening of poultry. 

 

9.                             On 13 January 2004, the World Health Organization (WHO) announced that it had received laboratory confirmation of three cases of H5N1 avian influenza in humans in the Hanoi region of Vietnam.  The samples came from two children and one adult who have since died.  Since October 2003, a total of 14 cases of severe respiratory disease have been identified in Hanoi and surrounding provinces. Thirteen of these cases are in children and one in an adult.  To date, 11 of these children and the adult have died.  However, there is so far no evidence that all these cases are caused by avian influenza.  Some of the cases have involved family members, but investigators are exploring the possibility that those who fell ill may have been exposed to a common source in poultry.  Four of the five families that have so far been interviewed reportedly recalled chickens dying in their villages.  According to the WHO, the evidence to date suggests that there is no sign of human-to-human transmission.

 

10.                         We did not import any live poultry and poultry meat from Vietnam in the past four years.

 

 

Avian influenza outbreak in Japan

 

11.                         The Ministry of Agriculture, Forestry and Fisheries of Japan reported to the OIE on 12 January 2004 that an H5 HPAI outbreak occurred in one layer flock in a farm in Yamaguchi Prefecture.  It was reported that about 6,000 chickens were found dead on the farm and another 30,000 chickens on the farm were killed. 

 

12.                         The strategy being used by Japan to control the outbreak includes (i) a stamping out policy of the affected farm; (ii) movement control of poultry within the country; and (iii) screening of poultry. 

 

13.                         In the first ten months of 2003, about 3,000 tonnes of poultry meat were imported from Japan accounting for less than 1% of the total volume of poultry meat imported to Hong Kong.  The only imports of live birds from Japan in the past 12 months were two birds imported to a zoo in December.  Both birds have completed their post arrival quarantine and are healthy. 

 

14.                         No human cases have been reported so far in connection with the Japanese outbreak.

 

 

Measures implemented in Hong Kong

 

15.                         The Government has approached the relevant authorities in South Korea, Vietnam and Japan to obtain more information on the situation in these countries.  As a precautionary measure, we have temporarily suspended the importation of live birds and poultry meat from these places.  We will continue to closely monitor the situation of the outbreaks in these places. 

 

16.                         In the light of the H5 avian influenza outbreaks in South Korea, Vietnam and Japan, we have stepped up our monitoring and surveillance efforts to minimize the risk of recurrence of avian influenza outbreaks in Hong Kong.  A meeting chaired by the Secretary for Health, Welfare and Food was held with the Director of Agriculture, Fisheries and Conservation and the Director of Food and Environmental Hygiene on 12 January 2004 to map out a strategy for preventing avian influenza outbreaks in Hong Kong.

 

17.                         At the farm level, biosecurity measures have been imposed to prevent the introduction of avian influenza viruses to farms.  In particular, to prevent infection from wild birds, bird proofing has been implemented on all local farms.  A territory-wide H5 vaccination programme has also been implemented since June 2003 in all local chicken farms as a supplementary measure to prevent the recurrence of an outbreak.  The Agriculture, Fisheries and Conservation Department (AFCD) will step up inspection of all local farms to monitor if any abnormal circumstances occur and if all biosecurity requirements are strictly observed.

 

18.                         To ensure similar levels of protection to both imported Mainland chickens and locally produced chickens, we have also reached agreement with the Mainland authorities on the vaccination of chickens for export to Hong Kong.  By 15 January 2004,  all live chickens available in the local market has been vaccinated.  The Food and Environmental Hygiene Department (FEHD) will conduct testing on the imported chickens to ensure that the immunity status of imported chickens is at a satisfactory level. 

 

19.                         The wholesale and retail markets are also thoroughly cleansed on a regular basis to maintain good hygiene standards.  All transport cages and vehicles are required to be cleansed and disinfected before being used for transporting chickens.  Since March 2003, the Government has implemented two rest days per month at retail outlets to reduce the viral load there, if any.  Poultry stall operators have to surrender all live poultry for disposal on detection of even one dead bird with H5 virus isolated.  AFCD and FEHD will step up monitoring of the wholesale market and retail outlets respectively to ensure that no abnormal circumstances occur. 

 

20.                         The Government has put in place a comprehensive and sensitive avian influenza surveillance programme covering local chicken farms, imported chickens, the wholesale market and retail outlets.  To detect the presence of any avian influenza viruses in the environment and the possible re-assortment of the viruses, the surveillance programme has been extended to cover wild birds, waterfowl in recreational parks and pet birds in the market.  This enables the Government to take responsive measures at an early stage to prevent the recurrence of outbreaks.  In 2003, a total of 17,409 samples were tested, among which 887 were samples from wild birds and recreational parks.  The last time that H5 virus was isolated was November 2003.

 

21.                         Hong Kong has an intensive surveillance system for human influenza.  At this time, human influenza activity in Hong Kong remains within historical limits and no H5N1 isolate has been detected.  The Department of Health will continue to closely monitor the human influenza activity. 

 

22.                         To maintain an effective strategy to address the avian influenza problem, we will review our control measures regularly to ensure that they have not outlived their usefulness and explore new options to resolve the problem in light of the changing circumstances.  In particular, we will remain vigilant in keeping our guard against any mutation or re-assortment of the virus that may have an impact on human health.

 

 

Health, Welfare and Food Bureau

Agriculture, Fisheries and Conservation Department

Food and Environmental Hygiene Department

Department of Health

January 2004

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