Veterinary advice should be sought from your local veterinarian before applying any treatment or vaccine. Not sure who to use? Look up veterinarians who specialize in poultry using our directory listing. Find me a Vet



Gapeworm infection (a common name for syngamiasis) is a parasitic disease caused by the common nematode parasite,Syngamus trachea (otherwise known as the gapeworm). S. trachea attach themselves within the duck's trachea, where they feed on their blood and reproduce.

The severity of the infection depends on the duck's age and size, and number of S. trachea present in the trachea. Younger ducks and smaller duck breeds are usually more severely affected then large duck breeds and older, adult ducks. This is related to them having a more narrower tracheal opening---meaning a smaller number of S. trachea can be present and still cause the duck to suffocate.

The presence of S. trachea in the duck's trachea causes clinical signs related to mild to extensive blocking of airflow. Ducks are most commonly seen:
  • 'Snicking', whihch is a combination of sneezing, coughing, and sideways flicking of their heads.
  • Gasping or 'gaping', in which they are seen extending their necks outward and gasping for breath through their opened bills.
  • Some may produce a hissing noise at the same time.

How Ducks are Infected

S. trachea can have a direct or indirect life cycle. Direct meaning that it reinfects the hosts themselves (other ducks, poultry, and even wild birds), and indirect meaning it can also be found within certain mollusc species (slugs, snails, and earthworms). Ducks become infected either by consuming one of the species of mollusc containing S. trachea, or by ingesting their eggs from the environment when an infected bird has coughed them up. Wild birds often act as reservoirs of S. trachea--pheasants, ruffed grouse, partridges, wild turkeys, magpies, meadowlarks, robins, grackles, jays, jackdaws, rooks, starlings and crows.


Emitting a hissing sound
Extending neck outward
Head shaking
Weight loss
Reduced egg laying


  • History
  • Clinical signs
  • Physical exam
  • Smears from the proventriculus, small intestine, and cecum


MethodMethod Summary
Fenbendazole5-20 mg/kg of body weight, administered orally, once a day for 5 days
Thiabendazole100 mg/kg of body weight, administered by mouth SID for 7-10 days

Reported Cases

  • Case 1: Gapeworm infection in a Macaw An adult, 900g female Ara ararauna from a project for the rehabilitation of the Brazilian fauna was kept in a collective nursery together with 12 specimens of the same species. Their diet was composed of typical fruits of the region, which were offered twice a day, and water ad libitum. The macaws had no previous history of anthelmintic treatment. The specimen evaluated presented progressive weight loss, constant sneezing, and reduced appetite for seven days. During physical examination the animal presented apathy, lethargy, spiked feathers, body condition score of 1/4, frequent sneezing, and inspiratory dyspnea. After this examination, the bird died, and the necropsy was performed. The postmortem findings were pale periocular, oral, and cloacal mucosae, cachexia, and presence of parasites of round shape, reddish color, with length of approximately 0.5 cm, in the proximal portion of the trachea. Another parasite with the same characteristics, but smaller in size, showing Y shape was found in the body. The trachea also showed colorless mucus and petechial hemorrhages in the proximal and middle portions of the mucosa. These parasites were subjected to morphological analysis in the Laboratory of Microscopy of the University Center of Triângulo and were identified as Syngamus trachea. Ref


  • Tilling the soil in the pens at the end of the growing season helps to reduce the residual infection.
  • Treating the soil to eliminate earthworms, snails and slugs
  • Administering a wormer at 15 to 30-day intervals
  • Including a drug at low levels continuously beginning 15 days after birds are placed in the infected pens



Risk Factors

  • Crowding of birds
  • Unsanitary living conditions
  • Access to snails, earthworms, and slugs

Also Consider