#calonectris

[2706/11080] Cory's shearwater - Calonectris borealis

Note: Clements considers Cory's shearwater to be conspecific with Scopoli's shearwater, C. diomedea.

Order: Procellariiformes (tubenoses) Family: Procellariidae (petrels, prions and shearwaters)

[2062/11056] Cape Verde shearwater - Calonectris edwardsii

Order: Procellariiformes (tubenoses) Family: Procellariidae (petrels, prions and shearwaters)

Cory’s shearwater is able to provide immune protection to its offspring up to six years after being vaccinated

Cory’s shearwater (Calonectris borealis) is a seabird that breeds annually in remote islets and islands. Characterized by long life expectancy, the species reaches sexual maturity after six years and its reproductive rate is very low (one chick per year). “With these characteristics, the consequences of an infection outbreak on a colony of seabirds may be devastating; it may be a threat to the restoration and viability of the affected population,” says Jacob González Solís.

The scientific team has studied seabirds’ immune response to a vaccine against Newcastle disease virus. The researcher Raül Ramos, first author of the article, explains that “the study simulates a viral infection with a vaccine and examines the species’ immune system in order to know how to act in case of real infection.”

Immune response in chicks and females

The study was conducted in a Cory’s shearwater colony in the island of Gran Canaria (Canary Islands) from 2008 to 2013. Authors evaluated the persistence of immunoglobulins or antibodies in mothers through time. The research has extended the results of a previous study developed by the same research team in 2011 which was focused on immunoglobulin persistence during chick growth.

To be exact, in 2008, researchers developed the first vaccination campaign in thirty females. Then, in 2010, they repeated it in a limited number of females to observe if a second exposure to the pathogen generated a quicker and more persistent response.

Chicks are protected six years after the vaccination

Results show that mothers are still able to transfer immunoglobulins to chicks six years after a vaccination, protecting their offspring against the pathogens that might infect the population. “Immunoglobulins are of female origin and maternal antibodies are transferred only when the egg yolk is formed,” points out Raül Ramos. “In the case of chicks, the average lifetime of immunoglobulins is twenty-five days.”

Besides extraordinary antibody persistence in vaccinated females, the study evidences a direct correlation between the amount of antibodies that the mother has when hatching and the amount received by the shearwater chick. In other words, the chick that is born during the year when the mother is vaccinated receives a great amount of antibodies. However, the chick of a female that was vaccinated years ago receives fewer antibodies and they are lost quicker during growth.