No abstract

Although West Nile Virus (WNV) has not been reported in Hawai'i, eventual introduction appears unavoidable with potential adverse effects on avian species. Nēnē (Branta sandvicensis) are endemic endangered Hawaiian geese that are susceptible to WNV. We demonstrate that a vaccine developed against WNV for humans (WN-80E) is also highly immunogenic in Nēnē and does not produce adverse biologic effects. Six captive, nonbreeding Nēnē were immunized with two 10-μg doses (4 wk apart) of the WN-80E recombinant protein adjuvanted with Montanide ISA720. Two Nēnē were similarly injected with "mock" preparation as controls. Blood samples were collected before the first dose, then 2 wk and 6 mo after the second dose. WNV-specific antibody titers were determined by an endpoint enzyme-linked immunosorbent assay. An unpaired t-test demonstrated significantly higher geometric mean titers for immunized vs. control groups 2 wk after dose 2 (4,129 and 100, respectively, P=0.010) and 6 mo after dose 2 (246 and 63, respectively, P=0.002). Daily observations revealed no swelling at the site of injection and no serious adverse biological effects from the immunization. The vaccine containing the WN-80E and Montanide ISA720 adjuvant appears to be safe and immunogenic in Nēnē. This protein-based WNV vaccine may be safer for use in Hawai'i than killed virus and live chimeric or recombinant canarypox-vectored vaccines because it cannot cause disease.

Feral cats (Felis catus) have long been implicated as nest predators of endangered ‘Ua‘u (Hawaiian Petrel; Pterodroma sandwichensis) on Hawai‘i Island, but until recently, visual confirmation has been limited by available technology. ‘Ua‘u nest out of view, deep inside small cavities, on alpine lava flows. During the breeding seasons of 2007 and 2008, we monitored known burrows within Hawai‘i Volcanoes National Park. Digital infrared video cameras assisted in determining the breeding behaviour and nesting success at the most isolated of burrows. With 7 cameras, we collected a total of 819 videos and 89 still photographs of adult and nestling ‘Ua‘u at 14 burrows. Videos also confirmed the presence of rats (Rattus spp.) at 2 burrows, ‘Ôma‘o (Myadestes obscurus) at 8 burrows, and feral cats at 6 burrows. A sequence of videos showed a feral cat taking a downy ‘Ua‘u chick from its burrow, representing the first direct evidence of ‘Ua‘u depredation by feral cat in Hawai‘i. This technique provides greater understanding of feral cat behaviour in ‘Ua’u colonies, which may assist in the development of more targeted management strategies to reduce nest predation on endangered insular bird species.

Millions of birds in the United States die annually due to vehicle collisions on roads. Collisions may be of particular interest for species of conservation concern, such as the endangered Hawaiian goose (Nēnē), which is endemic to Hawai‘i. Using a nearly 40-year dataset of Nēnē road mortality in and around Hawai‘i Volcanoes National Park, we sought to answer the following research questions: 1) has Nēnē mortality changed over time? 2) are there times of the year in which mortality is greatest and does it relate to specific events in the species’ lifecycle? 3) does age at mortality differ over time, space, or sex? 4) given that existing mortalities appear to occur only in certain locations, do the number of mortality events differ across these locations; 5) does mortality rate show any density dependence? and, 6) are mortality rates related to numbers of visitors or vehicles? Between 1977 and 2014, a total of 92 Nēnē died from vehicle collisions; while absolute mortality increased over this time, the mortality rate remained the same. Similarly, average age of mortality increased over time, but did not differ by location or sex. Between 1995 and 2014, Nēnē population size and mortality rates were not correlated. Mortality was greatest in November and December (breeding season) and lowest in June. Most of the mortality occurred along just three stretches of road in and around the park, with the number of mortalities split about evenly inside and outside of the park. Furthermore, Nēnē mortality was unrelated to the number of visitors or traffic volume in the park. These findings suggest vehicle collisions are a growing concern for Nēnē, but that management actions to reduce mortality can be targeted at specific road segments and times of the year.

While West Nile Virus (WNV) has not yet been reported in Hawaii, eventual introduction appears unavoidable. Nene are endemic, endangered Hawaiian geese, and are susceptible to WNV. The goal of this study is to demonstrate that a vaccine developed against WNV for humans (WN-80E) is also highly immunogenic in Nene, and does not produce adverse biological effects. Six captive, non-breeding Nene were immunized with two 10 µg doses (four weeks apart) of the WN-80E recombinant protein adjuvanted with Montanide ISA720. Two Nene were similarly injected with mock preparation as controls. Blood samples were collected prior to the first dose, at two weeks and six months after the second dose. Detailed observations were noted for 48 hours post injection, followed by daily observations of health status to monitor for adverse biological effects. WNV-specific antibody titers were determined by an endpoint ELISA. An unpaired t-test demonstrated significantly higher geometric mean titers for immunized vs. control groups at two weeks post dose two (4129 and 100, respectively, p = 0.0096) and at 6 months post dose two (246 and 63, respectively, p = 0.0023). No swelling was reported at any time during the study at the site of injection. No serious adverse biological effects were observed directly due to the immunization. The vaccine containing the WN-80E and Montanide ISA720 adjuvant appears to be safe and effective in Nene, and should be considered for widespread use in Hawaii.