To evaluate how avian influenza virus (AIV) circulates among the avifauna of the Antarctic and sub-Antarctic islands, we surveyed 14 species of birds from Marion, Livingston and Gough islands. A competitive enzyme-linked immunosorbent assay was carried out on the sera of 147 birds. Quantitative reverse transcription polymerase chain reaction was used to detect the AIV genome from 113 oropharyngeal and 122 cloacal swabs from these birds. The overall seroprevalence to AIV infection was 4.8%, with the only positive results coming from brown skuas (Catharacta antarctica) (4 out of 18, 22%) and southern giant petrels (Macronectes giganteus) (3 out of 24, 13%). Avian influenza virus antibodies were detected in birds sampled from Marion and Gough islands, with a higher seroprevalence on Marion Island (P = 0.014) and a risk ratio of 11.29 (95% confidence interval: 1.40–91.28) compared to Gough Island. The AIV genome was not detected in any of the birds sampled. These results confirm that AIV strains are uncommon among Antarctic and sub-Antarctic predatory seabirds, but they may suggest that scavenging seabirds are the main avian reservoirs and spreaders of this virus in the Southern Ocean. Further studies are necessary to determine the precise role of these species in the epidemiology of AIV.

The present report provides the first account of the shallow water hydroids of St. Helena, which comprises 17 species, and adds nine new records to the hydrozoan fauna of the Tristan da Cunha group of islands, raising their number to 34. A total of 34 species, belonging to five families of Anthoathecata and eight families of Thecata, are discussed herein. Although distributional data are given for each species, brief diagnoses are provided for the lesser known or unidentifiable species, and the common taxa are occasionally accompanied by succinct remarks. Illustrations are provided for nearly all species in order to justify their identification and to facilitate identification by others. Fiordlandia protecta and Filellum bouvetensis, both from Gough Island, represent the second world records and extend their known area of distribution.