Coronaviruses in wild birds - A potential and suitable vector for global distribution.

The recurrent appearance of novel coronaviruses (CoVs) and the mortality and morbidity caused by their outbreaks aroused a widespread response among the global science community. Wild birds' high biodiversity, perching and migratory activity, ability to travel long distances and possession of a special adaptive immune system may make them alarming sources of zoonotic CoV-spreading vectors. This review gathers the available evidence on the global spread of CoVs in wild birds to date. The major wild birds associated with different types of CoVs are Anseriformes, Charadriiformes, Columbiformes, Pelecaniformes, Galliformes, Passeriformes, Psittaciformes, Accipitriformes, Ciconiiformes, Gruiformes and so on. However, the main type of CoVs found in wild birds is gammacoronavirus, followed by deltacoronavirus. Consequently, it is imperative to enable thorough research and continuous monitoring to fill the study gap in terms of understanding their role as zoonotic vectors and the frequent appearance of novel CoVs.