16 January 1998
INFLUENZA A(H5N1) VIRUS FOUND IN DUCKS, GEESE
Influenza type A(H5N1) virus has been isolated in ducks and geese in Hong Kong, Special Administrative Region of China, according to results released yesterday by a joint World Health Organization (WHO)/Hong Kong University team of scientists. Influenza A(H5N1) had formerly been found only in chickens in Hong Kong.
The positive culture samples were taken from wild and domestic ducks and wild geese collected at markets in Hong Kong before the slaughter of approximately 1.6 million chickens and other birds in early January.
The number of ducks and geese which have tested positive for H5N1 or other, yet to be specified, H5 subtypes is small: so far, only 10 duck and goose cultures have tested positive. It is likely that at least a few more of the samples will be found positive for H5 virus when all retesting procedures have been completed. The total number of samples tested is more than 1 800, covering a wide range of species.
These results do not yet allow for a definitive determination of the initial source of the H5N1 virus. They also do not indicate, to date, that domestic ducks being raised on farms in Hong Kong have been infected with the H5N1 virus.
Given the current situation, the acting Chief Secretary for Administration of Hong Kong s regional government, Mr. Michael Suen, said on Wednesday, 14 January, that, "a preliminary conclusion [from our discussions is] that no killing of ducks at local farms is necessary at this stage."
In order to protect public health, the Government in Hong Kong is considering a number of options to ensure that live chickens and ducks are handled separately at all times. One option is to allow live chickens to reach retail outlets for slaughtering on purchase, but to kill ducks before they reach retail outlets.
"Because ducks and geese may occasionally carry influenza A viruses and not appear ill, consideration of separate handling for the marketing of such birds, as opposed to chickens, is prudent for the protection of public health," according to Dr Klaus Stohr of WHO s Division of Emerging and other Communicable Diseases Surveillance and Control (EMC).
WHO has been active in veterinary epidemiological investigations in Hong Kong. Two experts helped organize the sampling activities between 26 December 1997 and 9 January 1998. WHO has also been providing financial support, through its Collaborating Centre for Studies in the Ecology of Influenza in Animals at St Jude s Research Hospital in Memphis, Tennessee, USA, for the ongoing study of influenza reservoirs in animals and bird species in Hong Kong.
WHO is continuing to strengthen its surveillance activities for influenza in humans, birds and other animals in Hong Kong, Special Administrative Region of China, and other countries. AWHO-organized team of experts will be arriving on 16 January 1998 in Guangdong Province, China, to collaborate with the national authorities in their efforts to review ongoing influenza surveillance activities in Guangdong and Hong Kong.
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