Hong Kong officials said a Chinese pond heron found dead in an area near the border with China´s southern city of Shenzhen was probably infected with a strain of bird flu that killed dozens of people in Asia last year.

The city´s agriculture department will conduct more tests ``to confirm the nature of the virus,´´ the Hong Kong government said in a faxed statement.

If the bird was found to have H5N1, it would be the first time this year a fatal strain of the virus has been detected in Hong Kong, where the virus was initially found to have mutated into a form lethal to humans about seven years ago.

The bird was found in a restricted area in Lok Ma Chau and handed to agriculture officials by a rail worker on Jan. 10, the government said. Agriculture officials checked poultry farms within a 5-kilometer (3.1-mile) radius for other infections yesterday, the government said.

The agriculture official who collected the bird was wearing protective gear and will be under health observation.

The H5N1 strain first crossed species to humans from birds in Hong Kong in 1997 when an outbreak led to six deaths.

The outbreaks have led to the culling of millions of poultry and other birds in the region. A wild falcon was found dead in Hong Kong with the disease in last January.

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Chinese pond heron tests H5N1 positive

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Further tests on the carcass of a Chinese pond heron found in Lok Ma Chau have confirmed that the bird was H5N1 positive, a spokesman for the Agriculture, Fisheries and Conservation Department (AFCD) said today (January 13).

The spokesman stressed that the department would maintain frequent inspections on poultry farms to ensure that proper precautions against avian influenza had been implemented.

"We will continue to monitor the poultry farms closely. There is no abnormal mortality and the chickens show no symptoms of avian influenza," he said.

The department had inspected more than 20 chicken farms within five kilometres of where the Chinese pond heron was found.

The dead bird was collected by an AFCD staff member within a restricted area in Lok Ma Chau on January 10. A post-mortem examination indicated that it was an H5 suspect.

People are reminded to observe good personal hygiene. They should avoid personal contact with wild birds and live poultry and clean their hands thoroughly after coming into contact with them.

Ends/Thursday, January 13, 2005

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OIE report

AVIAN INFLUENZA IN HONG KONG, SPECIAL ADMINISTRATIVE REGION OF THE PEOPLE´S REPUBLIC OF CHINA
in a wild bird

Emergency report

Information received on 14 January 2005 from the Director of the Agriculture, Fisheries and Conservation Department (AFCD), Hong Kong:

Report date: 14 January 2005.

Nature of diagnosis: post-mortem and laboratory.

Date of initial detection of animal health incident: 10 January 2005.

Estimated date of primary infection: between 4 and 8 January 2005.

Outbreaks:

Location	No. of outbreaks
New Territories, ecological mitigation area of the Lok Ma Chau Spur Line Project	1

Description of affected population: a Chinese pond heron (Ardeola bacchus) (migratory bird).

Total number of animals in the outbreak:

species	susceptible	cases	deaths	destroyed	slaughtered
fau	...	1	1	0	0

Diagnosis: the bird was found dead on 10 January 2005 and was submitted for post-mortem and virological examination on the same day.

A. Laboratory where diagnosis was made: Tai Lung Veterinary Laboratory, AFCD.

B. Diagnostic tests used: the following tests were conducted on cloacal and tracheal swabs and lung and brain tissues:

- chick embryo inoculation with haemagglutination inhibition testing using specific reference sera from CVL⁽¹⁾ Weybridge, United Kingdom (OIE Reference Laboratory for avian influenza);

- viral genome detection by real-time RT-PCR⁽²⁾ tests using H5 specific primer sets from the Southeast Poultry Research Laboratory, Atlanta, Georgia, United States of America;

- N1 typing was conducted by conventional RT-PCR⁽²⁾ following procedures from the Department of Microbiology, Hong Kong University (HKU);

Chicken embryos were killed within 48 hours.

Genetic sequencing of the haemagglutinin cleavage site will be conducted at HKU.

C. Causal agent: avian influenza virus subtype H5N1.

Epidemiological details:

- This species of heron is distributed in East and South-East Asia, where it inhabits a wide range of habitats such as marshes, paddy fields, tidal mudflats, estuaries and flood plains. Its main diet consists of fish, worms, molluscs, small frogs and aquatic invertebrates.

- In the winter of 2003-2004, about 200-300 of these birds were recorded in the Deep Bay area of Hong Kong area (including Lok Ma Chau).

- No spread has been detected. All poultry farms within 5 km of where the heron was found have been checked and no unusual mortality or illness were detected.

- Local poultry farms are routinely under a constant monitoring and surveillance programme involving serological and virological testing and have individual farm biosecurity plans which include bird proofing of all sheds. All chicken farms are routinely vaccinated with inactivated H5N2 vaccine and each batch of chickens has 60 unvaccinated individually identified sentinels monitored throughout the production life of the batch.

- Extensive virus culture and surveillance is conducted in wholesale and retail poultry markets and in bird parks and wild bird populations throughout Hong Kong. During 2004, over 13,300 faecal or cloacal/tracheal swabs from poultry farms, 23,900 swabs from wholesale or retail live poultry markets, 4,738 swabs from waterfowl and aviaries in recreational parks, 5,322 swabs from pet bird shops and markets and 7,433 swabs from wild birds were tested in Hong Kong as part of the avian influenza surveillance programme. The only cases of H5N1 infection detected in 2004 were the peregrine falcon reported on 19 January (see Disease Information, 17 [5], 18, dated 30 January 2004) and the grey herons reported on 3 November and 13 December (see Disease Information, 17 [45], 332, dated 5 November 2004, and Disease Information, 17 [51], 382, dated 17 December 2004).

(1) CVL : Central Veterinary Laboratory.

(2) RT-PCR: reverse transcriptase - polymerase chain reaction