For many years past, Syngamus has been recognised as a serious trouble in both avian and mammalian hosts, and the course of the disease has been closely followed in several birds of economic importance. The symptoms are well known and have often been cited. Clinically the first symptom to appear is a characteristic sneezing and coughing in the affected bird. This is followed later by the best known symptom—the actual gaping—when the bird stretches its neck and opens its beak widely in its endeavour to ease respiration. There are minor signs such as a general debility with ruffled feathers but these are secondary and not specific to this disease. Internally in the trachea there is an increase in the secretion of mucus, which coupled with the presence of the gapeworms is sufficient to cause asphyxiation and the bird dies.