First detection of avian influenza virus (H4N7) in Giant Petrel monitored by geolocators in the Antarctic region

Abstract

This study presents the results of the virologic analysis and year-round movements of a Southern Giant Petrel that tested positive for avian influenza virus. Data were collected in two areas of Antarctica, where 299 Southern Giant Petrel adults and chicks were sampled. One-step real-time RT-PCR detected the presence of the avian influenza A virus in only one individual of the total Southern Giant Petrel sampled. The H4N7 subtype detected was compared to other H4N7 virus sequences and results suggest that segments of E96/H4N7 were closely related to avian influenza viruses of Anseriformes and Charadriiformes from North America. The geolocator that reported the year-round movements of the infected Southern Giant Petrel was retrieved. It was observed that this infected individual visited areas close to the Antarctic Peninsula during summer/spring and migrated to northern areas near South America and the Falkland Islands during the non-breeding season. Our results point out the first evidence of avian influenza virus H4N7 in Giant Petrels. Furthermore, the genetic similarity of the sequenced virus provides evidence of viral connections between North America and the Antarctic Peninsula. The migratory routes of several species in which avian influenza virus has been detected are coincident with the non-breeding area frequented by this single Southern Giant Petrel. Thus, movements of Southern Giant Petrel should be monitored to enable the determination of potential points of contact with other coastal seabird species along with the assessment of the dispersal routes of viruses.