title: Serological evidence of transmission of human influenza A and B viruses to Caspian seals (Phoca caspica).
abstract: Seroepidemiological surveillance of influenza in Caspian seals (Phoca caspica) was conducted. Antibodies to influenza A virus were detected in 54% (7/13), 57% (4/7), 40% (6/15) and 26% (11/42) of the serum samples collected in 1993, 1997, 1998 and 2000 by enzyme-linked immunosorbent assay (ELISA). In an hemagglutination-inhibition (HI) test using H1-H15 reference influenza A viruses as antigens, more than half of the examined ELISA-positive sera reacted with an H3N2 prototype strain A/Aichi/2/68. These sera were then examined by HI test with a series of naturally occurring antigenic variants of human H3N2 virus, and H3 viruses of swine, duck, and equine origin. The sera reacted strongly with the A/Bangkok/1/79 (H3N2) strain, which was prevalent in humans in 1979-1981. The present results indicate that human A/Bangkok/1/79-like virus was transmitted to Caspian seals probably in the early 1980s, and was circulated in the population. Antibodies to influenza B virus were detected by ELISA in 14% (1/7) and 10% (4/42) serum samples collected from Caspian seals in 1997 and 2000, respectively. Our findings indicate that seal might be a reservoir of both influenza A and B viruses originated from humans.
authors.affiliation: Otsuchi Marine Research Center, Ocean Research Institute, University of Tokyo, Iwate, Japan. cie20910@syd.odn.ne.jp
authors.forename: Kazue
authors.initials: K
authors.lastname: Ohishi
authors.forename: Ai
authors.initials: A
authors.lastname: Ninomiya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kida
authors.forename: Chun-Ho
authors.initials: CH
authors.lastname: Park
authors.forename: Tadashi
authors.initials: T
authors.lastname: Maruyama
authors.forename: Takaomi
authors.initials: T
authors.lastname: Arai
authors.forename: Etsuko
authors.initials: E
authors.lastname: Katsumata
authors.forename: Teruo
authors.initials: T
authors.lastname: Tobayama
authors.forename: Andrei N
authors.initials: AN
authors.lastname: Boltunov
authors.forename: Lev S
authors.initials: LS
authors.lastname: Khuraskin
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Miyazaki
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006385:Hemagglutination Inhibition Tests / Q000379:methods; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D006801:Humans; D009980:Influenza A virus / Q000145:classification / Q000235:genetics / Q000276:immunology*; D009981:Influenza B virus / Q000145:classification / Q000235:genetics / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology / Q000635:transmission / Q000662:veterinary*; D008297:Male; D009792:Oceans and Seas; D046048:Seals, Earless / Q000821:virology*
chemical_list: D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus