Pneumonia during the prepatent phase may cause signs of dyspnea and depression, whereas the adult worms and excess mucous in the trachea lead to signs of asphyxia and suffocation with the bird gasping for air [5, 6,7]. Otherwise we can say blockage of the bronchi and trachea with worms and mucus will cause infected birds to gasp for air. An infected bird often may give its head aconvulsiveshake and cough in an attempt to remove the obstruction from the trachea so that normal breathing may be resumed. The characteristic signs of ‘gapes’ are those of dyspnea and asphyxia, occurring in spasms on account of accumulation of mucus in the trachea. The bird shakes and tosses its head about and it may cough, or it extends the neck, opens the beak and performs gaping movements. They stretch out their necks, open their mouths and gasp for air producing a hissing noise as they do so. This “gaping” posture has given rise to the common term "gapeworm" to describeSyngamus trachea [5, 6]. Death resultsfrom asphyxia during such an attack or from progressive emaciation, anaemia and weakness caused by the parasite.Afore mentioned clinical signs first appear approximately 1-2 weeks after infection. Birds infected with gapeworms show signs of weakness andemaciation, usually spending much of their time with eyes closed and head drawn back against the body. Severely affected birds, particularly young ones, will deteriorate rapidly; they stop drinking and becomeanorexic. At this stage, death is the usual outcome. Adult birds are usually less severely affected and may only show an occasionalcoughor even no obvious clinical signs.EpidemiologyEggs may survive for up to 9 months in soil and L3for years within the earthworm or other transport host. Larval abundance was significantly and positively associated with temperature and relative humidity [8]. Disease is seen most frequently in breeding and rearing establishments where outdoor pens, such as are used for breeding pheasants. Infection may be initiated by eggs, passed by wild birds such as rocks and blackbirds, these may also infect earthworms. Heavy burdens may occur in turkeys kept in straw yards. They may, however, be dangerous carriers of the disease, from which other birds acquire infection. Hen-chicks, goslings and artificially reared game birds, especially pheasants, suffer mostly from the parasites [7].The effects of S. trachea are most severe in young birds especially in game chicks and turkey poults. Adult hens are not usually infected and guinea-fowl are little affected at any age. Turkeys are susceptible to infection at any age and some consider them to be the natural hosts of S. tracheahence adults often acting as carriers. Pheasants appear to be chiefly susceptible to infections ensuing in highmortality rates during outbreaks [5, 6]. The rapidly growing worms almost immediately obstruct thelumenof the trachea, causing suffocation. Turkey poults, baby chicks and pheasant chicks are most susceptible to infection. Turkey poults usually develop gapeworm signs earlier and begin to die sooner after infection than young chickens.Earthworm transport hosts are important factors in the transmission ofS. tracheawhen poultry andgame birdsare reared on soil. The longevity of infective third stage larvae
after reading this I'd think your duck would already be dead from sufficating if it was gape worms. If this has been going on 3 months.
