Vaccination protects endangered albatross chicks against avian cholera

Abstract

Global change is contributing to unprecedented expansions of infectious diseases in wildlife. Recurrent avian cholera outbreaks are causing dramatic chick mortality and population decline in endangered albatross colonies on Amsterdam Island, a critical seabird breeding ground in the Southern Indian Ocean. We manufactured a killed vaccine using a Pasteurella multocida strain isolated from a dead albatross in the field.We used this same bacterial strain to establish a serological assay allowing the monitoring of antibody levels following bird vaccination. Using this vaccine on chicks 2 weeks posthatching caused 100% seroconversion and reduced the death risk by a factor exceeding 2.5, raising fledging probability from 14% to 46%. These results suggest that using a specifically tailored vaccine could be a key tool to effectively protect endangered seabirds from disease outbreaks threatening them with extinction.

Exploring the infection dynamics of a bacterial pathogen on a remote oceanic island reveals annual epizootics impacting an albatross population

“…Infection rates were high overall, but varied among and within seasons, reaching high levels at the time when massive nestling die-offs were recorded, while adults had already left the colony. As expected considering the virulence of Pm [7,9,14], very few nestlings (≤ 20%) fledged in 2014/2015, 2015/2016 and 2016/2017, corresponding to the years with highest Pm prevalence. In contrast, in 2013/2014, prevalence was minimal, but non-null, and nestling survival exceeded 50%.…”

“…Nestlings are then mostly on their own in their nest until fledging in April, except during feeding visits by their parents [9]. We surveyed a naturally-delineated subcolony of approximately 250 albatross pairs where bird exposure to Pm has been monitored since the 2013/2014 breeding season [14]. Monitored nests were georeferenced and marked with alphanumeric tags to individually identify the nestlings within a breeding season.…”

“…Survival monitoring was focused on the sampled nestlings, in addition to up to 30 un-manipulated ( i.e , visually monitored without any handling) nestlings each year. Because sampling of the nestlings appeared to have no detectable effect on their survival [14], the two groups (sampled and un-manipulated) were pooled together in the survival analyses. In addition, tissue samples were collected from dead birds found on the colony.…”

“…Isolation and genotyping of the etiological agent from several hosts on Amsterdam Island supported the hypothesis of clonal infection, suggesting recent introduction of this agent [9]. The causal link between Pm infection and nestling mortality has been further addressed through experimental vaccination, which significantly increased nestling survival during avian cholera outbreaks [14].…”

Food supplementation protects Magnificent frigatebird chicks against a fatal viral disease

“…There is growing recognition that infectious diseases impact negatively wildlife (Smith, Sax, & Lafferty, 2006). Much effort has been dedicated to emphasize the role of infections in species endangerment (Smith et al, 2006) and to develop protective procedures against pathogens (Bourret et al, 2018). Yet, outbreaks of infectious diseases are occurring at an unprecedented rate due to global changes (Altizer, Ostfeld, Johnson, Kutz, & Harvell, 2013;Cunningham, Daszak, & Wood, 2017).…”