title: Antibody survey on avian influenza viruses using egg yolks of ducks in Hanoi between 2010 and 2012.
abstract: In Vietnam, numerous surveillance programs are conducted to monitor the prevalence of avian influenza (AI) viruses. Three serological methods-the agar-gel immunodiffusion test, hemagglutination inhibition (HI) test, and enzyme-linked immunosorbent assay-are well established for detection of AI virus antibodies in poultry sera. Several recent reports have validated egg yolk as an alternative source for detection of AI virus antibodies. In this study, we investigated AI virus antibodies in ducks by HI testing using egg yolk. Ten duck eggs were collected every month from 10 randomly selected markets in Hanoi from April 2010 to March 2012. The HI test was performed using low pathogenic avian influenza (LPAI) viruses (H3, H4, H6, H7, H9, and H11 subtypes) and highly pathogenic avian influenza (HPAI) viruses (H5N1 clade 2.3.4 and 2.3.2.1) as antigens. HI testing for H3, H6, and H9 was 29% positive in November 2010, 50% positive in October and November 2010, and 12% positive in June 2011. These results indicated that several epidemics of LPAI viruses had occurred during the study period. In addition, antibodies against H7 were negative. The results of HI testing for H5N1 showed that the reactivity of the dominant HI antibody shifted from H5N1 clade 2.3.4 to clade 2.3.2.1. In conclusion, egg yolk is useful for long term monitoring of AI virus antibodies and the use of egg-based antibody detection may contribute to improvements in animal welfare.
authors.affiliation: Center for Infectious Disease Research in Asia and Africa, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan. kozue@nagasaki-u.ac.jp
authors.forename: Kozue
authors.initials: K
authors.lastname: Hotta
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takakuwa
authors.forename: Toshiyo
authors.initials: T
authors.lastname: Yabuta
authors.forename: Trang T H
authors.initials: TT
authors.lastname: Ung
authors.forename: Tatsufumi
authors.initials: T
authors.lastname: Usui
authors.forename: Hang L K
authors.initials: HL
authors.lastname: Nguyen
authors.forename: Thanh T
authors.initials: TT
authors.lastname: Le
authors.forename: Mai Q
authors.initials: MQ
authors.lastname: Le
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Koichi
authors.initials: K
authors.lastname: Otsuki
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Ito
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Murase
authors.forename: Tetsu
authors.initials: T
authors.lastname: Yamashiro
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D004372:Ducks / Q000276:immunology* / Q000821:virology; D004530:Egg Yolk / Q000276:immunology* / Q000821:virology; D006385:Hemagglutination Inhibition Tests; D009980:Influenza A virus / Q000145:classification / Q000235:genetics / Q000276:immunology*; D005585:Influenza in Birds / Q000453:epidemiology / Q000276:immunology* / Q000821:virology; D011201:Poultry Diseases / Q000453:epidemiology / Q000276:immunology* / Q000821:virology; D018571:Sentinel Surveillance / Q000662:veterinary; D014744:Vietnam / Q000453:epidemiology
chemical_list: D000914:Antibodies, Viral
keywords: Avian influenza virus; Egg yolk; Hemagglutination inhibition test