Public health is main concern during closure of bird reserves

PUBLISHED : Saturday, 15 May, 2010, 12:00am
UPDATED : Saturday, 15 May, 2010, 12:00am

I refer to the letter by Eric Bohm, CEO of WWF-Hong Kong ('Inconsistent responses over bird flu hurt nature reserve's finances', May 10) and would like to provide some information about the precautionary measures against avian influenza.

The Mai Po Nature Reserve, being part of the Mai Po Inner Deep Bay Ramsar Site, is an important roosting and refuelling site for migratory birds.

It regularly supports more than 100,000 wild birds for the whole year and some 80,000 water birds in midwinter. Public health was our overriding concern behind closing the site when a dead bird within a three-kilometre radius of the nature reserve was found to harbour the H5 virus on March 30. According to the reserve's annual report, the site attracted a total of 26,000 visitors in 2009. The closure was therefore a precautionary measure to contain the possible spread of the avian influenza (AI) risk by minimising human contact with wild birds and their faecal droppings. Relevant guidelines were endorsed in 2006 by Legco's panel on food safety and environmental hygiene. There is no inconsistency in applying the guidelines as far as AI risk control is concerned.

The government has adopted the same precautionary measures for other government facilities that have a large number of wild birds, or birds in captivity, that may come into close contact with humans, namely the outdoor section of the Hong Kong Wetland Park and the walk-in aviaries owned or managed by the government.

Similar to the Mai Po reserve, the walk-in aviaries of Ocean Park were temporarily closed to visitors for 21 days in January 2008 after an H5-infected black-crowned night heron was found in the park. Unlike Mai Po reserve, Tai Po Kau Nature Reserve is not a place with a high congregation of wild birds and so the above measure does not apply.

However, upon discovery of any dead bird with the H5N1 virus, the government will arrange for thorough cleaning and disinfection, and step up surveillance.

As regards the treatment of wet markets, upon detecting H5N1 virus in a live bird, or an environmental swab sample in a wet market, all live poultry in that market will be culled and all poultry stalls there will be closed for 21 days. Surveillance in all other wet markets will be stepped up.

Moreover, since 2006 the government has been conducting surveillance of local wild birds, which includes the collection of dead birds throughout Hong Kong as well as faecal samples of wild birds in Mai Po reserve. To combat AI, the government has also carried out a series of enhanced measures such as banning the keeping of backyard poultry and strengthening bio-security requirements.

The government is conducting a review of the overall risk of AI in Hong Kong and will also review the associated guidelines for handling H5N1 detection from time to time. We thank WWF-HK's support in our work to safeguard public health and will continue to work closely with them on this front.

Dr Mary Chow, for director of agriculture, fisheries and conservation