Title Highly Pathogenic Avian Influenza Virus among Wild Birds inMongolia

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. Citation: Gilbert M, Jambal L, Karesh WB, Fine A, Shiilegdamba E, et al. (2012) Highly Pathogenic Avian Influenza Virus among Wild Birds in Mongolia. PLoS ONE 7(9): e44097. doi:10.1371/journal.pone. 0044097 Editor: Gavin J D. Smith, Duke-NUS Graduate Medical School, Singapore Received February 26, 2012; Accepted July 30, 2012; Published September 11, 2012 This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication. Funding: Support for this project was provided by the National Institute of Allergy and Infectious Disease, National Institutes of Health, Department of Health and Human Services (Contracts HHSN266200700007C, HHSN266200700009C, and HHSN266200700005C), the United States Agency for International Development (USAID), the World Bank, and the Food and Agriculture Organization of the United Nations. DOJ was supported by generous funding from the Dunemere private foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: DOJ was supported by generous funding from the Dunemere private foundation. This does not alter the authors’ adherence to all the PLoS ONE policies on sharing data and materials. * E-mail: mgilbert@wcs.org