The Council of Agriculture confirmed yesterday an outbreak of a lesser strain of the bird flu virus H5N2 at a chicken farm in Kaohsiung County’s Luchu Township (路竹).
“The problem has been resolved. Starting in October, the farm was disinfected and we monitored the situation as if it were a highly pathogenic virus. The affected chickens were culled on Nov. 14,” Agriculture Minister Chen Wu-hsiung (陳武雄) told a press conference yesterday.
Chen said the results of a second round of samples from the affected chicken farm were confirmed by a panel of experts to be a low-pathogenic strain of H5N2.
Avian influenza has many different subtypes, including H5N1 and H5N2. The H5N1 subtype is highly pathogenic and can cause fever, coughing, sore throat, muscle ache, pneumonia or death when transmitted from birds to humans. There are no reports of H5N2 transmission to humans.
News of the outbreak were first made public by the council at a press conference on Wednesday, during which Deputy Minister Hu Sing-hwa (胡興華) said the council suspected an outbreak had occurred at a Kaohsiung chicken farm, adding that an investigation had been launched on Oct. 21.
Asked why it had taken so long for the test results to be made public, Animal Health Research Institute deputy director Lee Shu-hui (李淑慧) said “the examination requires careful work and is a complex process.”
“Our first results on Nov. 12 showed what looked like a high-pathogenic strain of H5N2, but as less than 3 percent of chickens in the population died, the result did not agree with the lab test,” Lee said.
To ensure they did not miss a potential threat, Lee said her team decided to do a second examination while seeking to avoid causing a panic. She said that as soon as the lab had the slightest evidence that there may have been a bird flu outbreak in October, she informed the council’s Bureau of Animal and Plant Health Inspection and Quarantine to initiate epidemic prevention mechanisms.
While the affected farm was thoroughly disinfected, farms within a radius of 3km have also been monitored since October, she said.
“After viral separation and cultivation, second results showed that the chickens had a H5N2 Intravenous Pathogenicity Index [IVPI] of 0.89, which makes it low-pathogenic,” she said.
An IVPI over 1.2 would be high-pathogenic.
Responding to comments by former minister of health Twu Shiing-jer (�?�) that testing for avian flu would only take one to two days, Lee said that what Twu was referred to was identifying H5N1 contamination in humans.
“I can also have results within two days, but my results may show a negative while a longer cultivation time may show a positive result,” she said.
Regarding the risk to humans, Animal and Plant Health Inspection and Quarantine Director-General Watson Sung (宋華聰) said there were no known cases of H5N2 mutating into the H5N1 strain, which can affect humans.
This was the only instance of bird flu in Taiwan, Soong said, adding that “high” or “low” pathogenic referred to chickens, not humans.
“On Nov. 14, the farm owner voluntarily culled all the chickens as a precautionary measure,” Chen said. “Now that we have confirmed the results, we will report the case to the World Organization for Animal Health. We will also continue to monitor the 76 chicken farms around the affected farm for three months before applying for poultry exportation to Japan.”