© 2017 SpatioEpi.com
Map created by CUHK SpatioEpi Group
As of 10 March 2017, 21 human cases of avian influenza H7N9 have been reported in Hong Kong. All were imported cases from China, as the patients had history of travelling to Mainland China and some had possible exposure to poultry. The map shows the suspected infection locations of these cases (yellow dots) in China. In retrospect, the first human case of H7N9 was reported in China in March 2013. Globally over 1300 cases have been reported. The geographic distribution of all cumulative cases by province (as of 10 March 2017) is shown in graduated colour. The spatiotemporal relationship between H7N9 cases in Hong Kong and Guangdong is a cause for concern. This also suggests that the future occurrence of H7N9 in Hong Kong would depend largely on the control of avian influenza outbreaks in Guangdong Province. Data for the map were obtained from multiple media sources derived from reports in different health authorities.
What is avian influenza? 什麼是禽流感?
Is human susceptible? 人會感染禽流感嗎?
Vaccine? Prevention? 如何預防？
Influenza is a respiratory infection caused by the influenza virus, different forms of which are normally circulating in not just human beings but pigs and birds. All influenza viruses are divided into A, B and C, and further distinguished by their H and N antigens. There are currently 18 H (standing for haemagglutinin) and 11 N (standing for neuraminidase) antigens. Epidemics occurred when novel viruses are introduced to the human population. Pandemic influenza A (H1N1), previously referred as Swine flu, was an example causing worldwide outbreaks in 2009. The genetic structure of this influenza virus contains segments from pig, bird and human, reflecting the occurrence of reassortment. Studies suggested a case fatality rate of 0.4% for the novel infection, and a higher tendency for causing disease in young people compared to other forms of seasonal flu. Since 2009, the same virus has continued to cause outbreaks in different populations at different timepoints.
Hong Kong Government has implemented a number of preventive measures to reduce the risk of avian influenza outbreaks in the territory. For example, backyard poultry keeping is prohibited and local poultry farms are inspected on a regular basis. For chickens in local farms and imported chickens, vaccination is required and virological testing for H5 antigen is enhanced. At retail level, live poultry is not allowed to be kept overnight, and two 'rest days' per month have been introduced to all poultry stalls in public markets and fresh provision shops selling live poultry for thorough cleansing.
In addition, poultry workers and cullers are also invited to be vaccinated against seasonal influenza, so the chance of genetic reassortment between human and avian influenza viruses can be minimized.
Further information 詳細資料