Worldwide pandemics of @entity1 @entity683 virus caused extensive morbidity and mortality around the world had been documented in the 20th century. However, the mechanisms involved in the emergence of novel @entity683 virus and the epidemiological factors leading to pandemics are unpredictable. Southern China is postulated as the epicentre of @entity683 epidemics due to its agricultural-based communities and high population density. Pandemic @entity683 viruses are through to arise from avian viruses through genetic reassortment among @entity683 viruses. An @entity683 virus (H5N1) known to infect only birds previously was found to infect @entity1 causing disease and @entity204 in Hong Knog in 1997 and the outbreak involved 18 @entity1 with six deaths. Prior to the @entity1 outbreak, the H5N1 virus was found to cause extensive @entity204 in @entity1573 in three farms in Hong Kong. The significance of this outbreak raised worldwide concern on the possibilities that such an @entity683 virus may become the next @entity683 pandemic strain. Investigations were initiated to find the source of the virus. In addition the extend of spread in individuals in contact with the index case and infected poultry was studied by H5-specific serology. Results demonstrated that individuals in close contact with the index case or with exposure to poultry were at risk of being infected. Out of the 18 cases of @entity1 @entity281 , eleven had severe @entity281 with symptoms of @entity55 and @entity881 . All severe cases presented with lower @entity1729 and @entity2905 and six eventually died. Case-fatality ratio was high among @entity1 over 12 years of age (five out of nine). Control measures aimed at reducing exposure of @entity1 to potential H5-positive poultry were instituted which included culling of all poultry in Hong Kong, the segregation of water fowls and @entity1573 , and the introduction of import control measures for @entity1573 . Such measures had successfully controlled the outbreak and continuous surveillance of the poultry in Hong Kong of H5N1 @entity281 is maintained to minimize future @entity1 exposure.

XXXX (H5N1) in Hong Kong: an overview.

@entity1 :: ('9606', 'Species') :: ['human', 'patients'] @entity55 :: ('MESH:D011014', 'Disease') :: ['pneumonia'] @entity2905 :: ('MESH:D008231', 'Disease') :: ['lymphopenia'] @entity683 :: ('MESH:D007251', 'Disease') :: ['influenza'] @entity1573 :: ('9031', 'Species') :: ['chickens', 'chicken'] @entity281 :: ('MESH:D007239', 'Disease') :: ['infection'] @entity1729 :: ('MESH:D012141', 'Disease') :: ['respiratory infection'] @entity881 :: ('MESH:D009102', 'Disease') :: ['multi-organ failure'] @entity204 :: ('MESH:D003643', 'Disease') :: ['death']
@entity683 :: (MESH:D007251,Disease) :: ['Influenza A']
