Captive Rearing and Release of Bar-headed Geese (Anser indicus) in China: A Possible HPAI H5N1 Virus Infection Route to Wild Birds

Abstract

In April–June 2005, more than 6,000 birds, including more than 3,000 Barheaded Geese Anser indicus, died at Lake Qinghai, northern China, during an outbreak of highly pathogenic avian influenza (HPAI) H5N1 (Chen et al., 2006). In spring 2006, more waterbirds, again mainly Bar-headed Geese (939 recorded at three Qinghai sites but not counted at others), died at four sites in Qinghai province and three in Tibet. Two virus isolations, from a Bar-headed Goose and a Great Black-headed Gull (Larus ichthyaetus), were reported from Lake Qinghai in 2007 (Li et al., 2010) and in May 2009, more wild birds (species not recorded) died at two sites in Qinghai province (Wang et al., 2008; World Organisation for Animal Health [OIE], 2010). In May 2010, dead wild birds, including Barheaded Geese, were reported from Nagqu province, Tibet (OIE, 2010). In 2005, 2006, 2009, and 2010 outbreaks on the Qinghai-Tibet plateau were contemporaneous with or followed by outbreaks in wild birds in Mongolia and southern Russia (OIE, 2010). Virus isolation from dead wild birds at Lake Qinghai in 2005 revealed a new strain of HPAI H5N1, designated Clade 2.2 (World Health Organization/World Organisation for Animal Health/Food and Agriculture Organization, 2008), which has subsequently spread to Europe and Asia (Feare, 2007). Although there had been outbreaks in poultry in Lanzhou, approximately 300 km from Lake Qinghai, and in the vicinity of Lhasa, Tibet (OIE, 2010), the evolution of HPAI H5N1 viruses was not studied in northern China (Smith et al., 2006), and the origin of the Qinghai stain remains a mystery. After the 2005 HPAI H5N1 outbreak at Lake Qinghai, one of the authors (T.K.) discovered Chinese-language internet media bulletins that described captive rearing of Bar-headed Geese on China’s central high plateau. These reports lack detail but describe practices that promote contact between captive-bred geese and domesticated and wild birds. Our aim here is to summarize the salient information from these reports because they present a possible scenario for emergence of the Qinghai Clade 2.2 viruses and its occurrence in wild birds. Captive breeding of Bar-headed Geese began in 2003 at Yamzho Yumco Lake, about 100 km south of Lhasa, Tibet, by the ‘‘Lhasa Nida Natural Ecology Development Bar-headed Goose Artificial Breeding Company.’’ Several hundred abandoned Bar-headed Goose eggs were collected from a declining colony, claimed to comprise 30,000 birds, at the lake and were artificially incubated, with 99% reared to fledging. The enterprise was extended to Xaina County, Nagqu Prefecture (about 300 km NE of Lhasa), where 500 Bar-headed Geese were successfully raised ‘‘to meet market demand.’’ The company also contracted production to a villager in Gonggar (Meldrogonkar) County, south of Lhasa. In 2006 another breeding unit was established in the same town, at a wetland and reservoir suitable