A recent review cited by ProMED Mail emphasized the role of Laridae the Family comprising gulls and terns in intercontinental and regional dissemination of avian influenza viruses.

The article noted, “For physiological and ecological reasons, airborne transmission may occur more frequently in Laridae than in Anatidae (ducks, geese and swans) that would favor the evolution of taxon-specific strains.”  The ProMED commentator noted that Laridae generally live longer than Anatidae and accordingly, have evolved stronger and new responses that could lead to different levels of infection.  Isolates from Laridae demonstrated reassortment among AIV strains, including incorporation of Eurasian genes that appeared in the 2022 North American epornitic.

The authors of the review stress the need for epidemiologic investigations to define the role of gulls and terns in introduction of AIV into coastal and inland areas through contact with endemic wild birds, migratory waterfowl, marine and terrestrial mammals. Common terns (Sterna hirundo) were suggested as a reservoir of avian influenza following extensive mortality in this species along the southeastern coast of South Africa in 1961. It is noted that H5N1 Avian Influenza was diagnosed in clinically affected gulls in Labrador in late December 2021 at the onset of the 2022 H5N1 epornitic.  Sea birds may be associated with infection of seals along the coast of Maine with mortality recorded since Spring of this year.  Gulls are extending inland and are well adapted to landfills and shopping centers with open dumpsters in addition to lakes and ponds in suburban areas.