Mongolia combines a near absence of domestic poultry, with an abundance of migratory waterbirds, to create an ideal location to study the epidemiology of highly pathogenic avian influenza virus (HPAIV) in a purely wild bird system. Here we present the findings of active and passive surveillance for HPAIV subtype H5N1 in Mongolia from 2005–2011, together with the results of five outbreak investigations. In total eight HPAIV outbreaks were confirmed in Mongolia during this period. Of these, one was detected during active surveillance employed by this project, three by active surveillance performed by Mongolian government agencies, and four through passive surveillance. A further three outbreaks were recorded in the neighbouring Tyva Republic of Russia on a lake that bisects the international border. No HPAIV was isolated (cultured) from 7,855 environmental fecal samples (primarily from ducks), or from 2,765 live, clinically healthy birds captured during active surveillance (primarily shelducks, geese and swans), while four HPAIVs were isolated from 141 clinically ill or dead birds located through active surveillance. Two low pathogenic avian influenza viruses (LPAIV) were cultured from ill or dead birds during active surveillance, while environmental feces and live healthy birds yielded 56 and 1 LPAIV respectively. All Mongolian outbreaks occurred in 2005 and 2006 (clade 2.2), or 2009 and 2010 (clade 2.3.2.1); all years in which spring HPAIV outbreaks were reported in Tibet and/or Qinghai provinces in China. The occurrence of outbreaks in areas deficient in domestic poultry is strong evidence that wild birds can carry HPAIV over at least moderate distances. However, failure to detect further outbreaks of clade 2.2 after June 2006, and clade 2.3.2.1 after June 2010 suggests that wild birds migrating to and from Mongolia may not be competent as indefinite reservoirs of HPAIV, or that HPAIV did not reach susceptible populations during our study.

SummaryEastern Mongolia supports one of the most important breeding populations of the White-naped Crane Antigone vipio (WNC), which is classified as ‘Vulnerable’ by the IUCN. Large numbers of WNCs were found to be breeding at high densities within the Ulz River basin during surveys conducted in 2000 and 2001, along a 270 km section of the river. Following these surveys, an extended drought continuing for at least a decade has threatened wetland ecosystems throughout Eastern Mongolia. This study reports the findings of surveys conducted in 2010 and 2011 along the same section of the Ulz River surveyed a decade earlier, as well as a generalised survey of other sites where breeding WNCs had previously been recorded. Along the Ulz River, populations declined from 42 territorial pairs in 2001 to 17 in 2011. Estimates of detection probability using distance sampling and occupancy methods at two locations gave consistent results of 23%–27% detectability. With a minimum population of 234 WNCs observed across all sites in 2011, these detection probabilities suggest that the areas surveyed support the majority of breeding WNCs in the western population. Although we cannot exclude the movement of WNCs beyond the survey area, these findings also suggest that the population has declined between 2001 and 2011. Exploration of key habitat variables using occupancy models and generalized linear mixed models found that WNCs favoured areas of high wet vegetation (estimated as ‘wet meadow’ coverage and using normalized difference vegetation index), and low grazing pressure. Given the importance of water resources to WNCs and nomadic herding communities, use of wetland habitat must be carefully managed to balance the needs of cranes and people, particularly during periods of drought.

SummaryPallas’s Fish Eagle Haliaeetus leucoryphus (PFE) is sparsely distributed across a vast swathe of central, eastern and southern Asia, and is classified as ‘Vulnerable’ by IUCN on the basis of population size and reports of declines in many areas. Mongolia has long been considered a breeding stronghold for the species, but evidence to support this is unclear. Our objective was to assess the current distribution and status of the PFE in Mongolia to enable a more accurate assessment of the species’ conservation status, through collation of existing information from the historical literature, and a contemporary survey of historical sites and potential PFE breeding habitat. Thirty-four traceable locations were identified in the historical literature, of which breeding activity had been recorded in seven. Field surveys were conducted at a total of 77 sites throughout the study period (2005–2011) between April and October, including 21 of the historical PFE locations. PFE were observed at eight sites, all of which were historical PFEs locations, and no evidence of breeding activity was recorded. These findings suggest that Mongolia is not (and may never have been) a breeding stronghold for the PFE. The lack of eagles at 13 of 21 historical sites surveyed, coupled with a lack of sightings of birds at alternative locations is suggestive of a decline in site occupancy. Observations of juvenile eagles within one month of the spring thaw suggests that at least a proportion of Mongolian PFEs are breeding at southern latitudes, and future studies to establish these migratory linkages are warranted. These findings, coupled with evidence of declines in other parts of the PFE range indicate a need to re-evaluate the species’ conservation status, and in particular to determine the number of mature PFEs present in suitable habitat in the Indian Subcontinent and Myanmar between November and March.

Mongolia combines a near absence of domestic poultry, with an abundance of migratory waterbirds, to create an ideal location to study the epidemiology of highly pathogenic avian influenza virus (HPAIV) in a purely wild bird system. Here we present the findings of active and passive surveillance for HPAIV subtype H5N1 in Mongolia from 2005-2011, together with the results of five outbreak investigations. In total eight HPAIV outbreaks were confirmed in Mongolia during this period. Of these, one was detected during active surveillance employed by this project, three by active surveillance performed by Mongolian government agencies, and four through passive surveillance. A further three outbreaks were recorded in the neighbouring Tyva Republic of Russia on a lake that bisects the international border. No HPAIV was isolated (cultured) from 7,855 environmental fecal samples (primarily from ducks), or from 2,765 live, clinically healthy birds captured during active surveillance (primarily shelducks, geese and swans), while four HPAIVs were isolated from 141 clinically ill or dead birds located through active surveillance. Two low pathogenic avian influenza viruses (LPAIV) were cultured from ill or dead birds during active surveillance, while environmental feces and live healthy birds yielded 56 and 1 LPAIV respectively. All Mongolian outbreaks occurred in 2005 and 2006 (clade 2.2), or 2009 and 2010 (clade 2.3.2.1); all years in which spring HPAIV outbreaks were reported in Tibet and/or Qinghai provinces in China. The occurrence of outbreaks in areas deficient in domestic poultry is strong evidence that wild birds can carry HPAIV over at least moderate distances. However, failure to detect further outbreaks of clade 2.2 after June 2006, and clade 2.3.2.1 after June 2010 suggests that wild birds migrating to and from Mongolia may not be competent as indefinite reservoirs of HPAIV, or that HPAIV did not reach susceptible populations during our study.

Background: Since 2005, highly pathogenic avian influenza A H5N1 viruses (Goose/Guangdong/1/96-H5 lineage) have spread from Asia to Africa and Europe, infecting poultry, humans and wild birds. Subsequently, avian influenza surveillance has increased worldwide. Mongolia is a good location to study influenza viruses in wild birds within Asia because the country has very low densities of domestic poultry and supports large concentrations of migratory water birds. We conducted avian influenza surveillance in Mongolia over two time periods from 2009 to 2018, utilizing environmental fecal sampling.Methods: Fresh fecal samples were collected in areas where wild water birds, including orders Anseriformes and Charadriiformes, congregated. Hemagglutinin (HA) and neuraminidase (NA) subtypes of positive samples were identified through viral isolation or molecular assays, with pathogenicity determined by HA subtype or sequencing the HA cleavage site.Results: A total of 10,222 samples were collected and tested for avian influenza virus. Of these, 7,025 fecal samples were collected from 2009-2013, and 3,197 fecal samples were collected from 2016-2018 period. Testing revealed 175 (1.7%) positive samples for low pathogenicity influenza A, including 118 samples from 2009-2013 (1.7%) and 57 samples from 2016-2018 (1.8%). Over the period and locations of surveillance no influenza A viruses were detected in association with a wild bird mortality event. HA and NA subtyping of all positives identified eleven subtypes of HA (H1-H8; H10-H12) and nine subtypes of NA (N1-N9) in 29 different combinations. Within periods, viruses were detected more frequently during the fall season (August to October, 2.5%; 95% CI 2.1-2.9%; 146/5,750) than the early summer (April to July, 0.6%; 95% CI 0.4-0.9%; 29/4,472).Conclusion: Mongolia is an important location for wild birds and is positioned as a crossroad of multiple migratory bird flyways. Breeding birds from Mongolia and further north pass through the country to wintering areas as widespread as southern Africa, the Indian Subcontinent, Southeast Asia and Australasia. Our work demonstrates the feasibility of using an affordable environmental fecal sampling approach for avian influenza surveillance and contributes to understanding the prevalence and ecology of low pathogenicity avian influenza viruses in this important location, where birds from multiple flyways mix.