Serological evidences of influenza A virus infection in Antarctica migratory birds

The possibility of the introduction of infectious agents to Antarctica animal life and its spread from Antarctica to other continents are recognized issues since the signature of the Antarctica Treaty. The migratory birds could be a potential vector for infectious agents The aim of this work was to look for evidences of influenza A infection in different species of migratory birds from Antarctica. The search was done by antibody titration via haemagglutination inhibition test with inactivated antigens prepared with A/Sydney/5/97(H3N2), A/Bayem/7/95(H1N1), A/Texas/36/ 91(H1N1), A/Hong Kong/1073(H9N2), an A (H5) strain and A/Tky/Va/4529/02(H7N2) viruses, with the last three antigens given by the Influenza Branch, CDC, USA. Between December and May 2001 and 2002, 302 sera were collected in Bahia Esperanza, Peninsula Antarctica; Peninsula Potter, Isla 25 de Mayo; Punta Armonia, Isla Nelson, and Islas Shetland del Sur. The sera were treated with RDE and adsorbed with turkey red blood cells. The sampled species were Pygoscelis adeliae, Pygoscelis antarctica, Pygoscelis papua, Macronectes giganteus and Catharacta spp. The 2.3%, 11.6%, 31.4%, 0.00%, 12.25%, 0.3% of the tested birds had an antibody titer higher or equal to 40 for A/Sydney/5/97(H3N2), A/Bayem/7/95(H1N1), A/Texas/36/91(H1N1), A (145) strain, A/Tky/Va/ 4529/02(H7N2) and A/Hong Kong/1073(H9N2) viruses, respectively. The highest titers were found in P. papua and M. giganteus with the A(H1N1) antigens. These results show the infections of the studied birds with influenza A viruses of the subtypes A(H1), A(H3), A(H7) and A(H9). This is the first communication of indirect evidences of influenza A infection in migratory aquatic birds of Southern Shetland Island and Bahia Esperanza, Antarctica. (C) 2004 Elsevier B.V. All rights reserved.