Tracheal worms

Infection by tracheal worms often results in respiratory distress due to their location in the trachea or bronchi and their obstruction of the air passage. Infections by these parasitic nematodes or roundworms in waterbirds, primarily ducks, geese, and swans, are usually due to Cyathostoma bronchialis and infection of land birds are usually due to Syngamus trachea. However, both genera infect a variety of species, including both land and waterbirds. Infections with S. trachea have been more extensively studied than infections with Cyathostoma sp. because of its previous importance as a disease-causing parasite of poultry in many parts of the world. Changes in husbandry practices to modern intensive methods for poultry production have essentially eliminated S. trachea as an agent of disease in chickens, but it is an occasional cause of disease in turkeys raised on range.