In Asia, Taiwan, Vietnam, and South Korea have recorded new outbreaks of highly pathogenic avian influenza (HPAI) to the World Organisation for Animal Health (OIE) in the past week. There have also been cases in poultry in the western African state of Niger.
Research from Hong Kong sheds new light on the apparent rise in China of human cases of H7N9 influenza, which have been linked to exposure to sick poultry.
More than 138,000 Taiwanese poultry succumb to HPAI
Taiwan has been battling to control HPAI of the H5N2 variant in poultry for more than two years.
According to the animal health agency’s latest report to the OIE, there were a further eight outbreaks of the disease in the week starting March 31. Affected were seven flocks of native chickens and one of geese, and more than 138,000 birds died or were destroyed as a result. Five of the outbreaks were in the county of Yunlin, two in Chiayi, and one at a slaughterhouse in the city of Kaohsiung.
New avian flu cases reported in Vietnam, South Korea, Hong Kong
According to a recent veterinary authority report to the OIE, there have been four new outbreaks of HPAI in Vietnam, all involving what is described as “backyard flocks.” Two outbreaks involving the loss of 6,500 birds were caused by the H5N6 virus in the same district in the central province of Thua Thien-Hue. A further 3,670 died or were destroyed as a result of the H5N1 virus variant in two other outbreaks in the southern province of Vinh Long, and Quang Ninh in the north east, bordering China.
The H5N6 HPAI virus was first detected in poultry in South Korea in November of 2016. Nine outbreaks that started during that month have been reported to the OIE by the national animal health agency in the last week. More than 305,000 poultry died or were destroyed as a result. Eight of the outbreaks were in duck flocks in North Chungcheong province, and the other affected flock included more than 231,000 chickens in Gyonggi-do, which surrounds the capital city, Seoul, in the northwestern part of the country.
Hong Kong’s veterinary authority has informed the OIE about its first detection of the H5N6 HPAI virus. A common Passerine songbird, found dead in Kowloon city, tested positive for the virus in the first week of April.
Avian flu returns to poultry in Niger
Having detected a small number of HPAI outbreaks caused by the H5N1 virus in Tillaberi region around the turn of this year, the H5N8 virus has recently been detected in a backyard flock in the same region of Niger. According to the official report to the OIE, 40 birds were lost to the disease in the third week of January this year.
New research reveals cause of China’s H7N9 flu spike in humans
Scientists at Hong Kong University (HKU) have identified a mutation in the H7N9 avian influenza A virus, which allows it to infect humans more easily, while still circulating effectively within the poultry population. It appears these abilities of the virus are conferred by a mutation in the form of a unique nucleotide substitution in a previously undefined section of the virus RNA.
Medical experts had been seeking to understand the unusual pattern in human infections with the H7N9 virus in China. The first cases were in the east of the country in 2013, and numerous human infections have been confirmed each year since then. However, there has been a spike in new infections this year, with 121 deaths among the more than 380 human cases in the first three months of 2017. This was despite the closure of live poultry markets in Chinese cities since 2013.
The latest findings will help scientists to monitor for any similar mutations in this and other avian influenza viruses in future, and they offer new hope in the development of drugs to control the virus.
Conducted at the HKU’s State Key Laboratory for Emerging Infectious Diseases and Department of Microbiology at the Li Ka Shing Faculty of Medicine, the research was published last month in the journal, Nature Communications.
