Foot-and-mouth disease: susceptibility of domestic poultry and free-living birds to infection and to disease--a review of the historical and current literature concerning the role of birds in spread of foot-and-mouth disease viruses.
Ruminants and pigs are the dominant natural hosts of food-and-mouth disease (FMD) viruses. Approximately 70 additional mammalian species are found to be susceptible under natural or experimental conditions. Reptilia, amphibia, and fish are probably naturally resistant to infection. According to the reviewed literature, domestic birds (chickens, turkeys, guinea fowl, ducks and geese) have been experimentally infected with some strains of FMD viruses and may develop lesions suggestive of FMD such as vesicular lesions on the comb, wattles, eye lids, and feet. Since chickens are to some extent coprophagous, chickens get infected by ingestion of virus under conditions of natural exposure or their plumage gets contaminated in an infectious environment. Thus, domestic birds kept in free-run systems may serve as virus vectors for short distances. Free-living birds, especially starlings (Sturnus vulgaris), sea gulls (Larus canus), house-sparrows (Passer domesticus) have been successfully experimentally infected and developed vesicular lesions on the skin and mucosal membranes of the mouth. During epizootics of FMD the plumage of these free-living birds can be contaminated with FMD viruses and the virus is spread over long distances during migration periods in spring and autumn. Thus migrating birds may assume an active role in long distance dissemination of FMD viruses.