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

Gizzard Worm Infection

Stomach Worm Infection, Amidostomiasis, Venticular Nematodiasis

Gizzard worm infection is a parasitic disease caused by a specific type of roundworm (nematode), called gizzard worms ( Amidostomum spp. and Epimidiostomum spp.). Gizzard worms are quite common in ducks and other waterfowl that are kept unsanitary conditions in which there is a large accumulation of feces concentrated in the environment where the birds are kept. The severity of the infection depends on the number of nematodes present, age, and overall immune status of the bird. Adult ducks are often subclinically infected (infected without showing clinical signs of disease). Ducklings are more likely to suffer from severe, heavy infections with corresponding clinical signs. Gizzard worms cause the most damage to the gizzard, resulting in erosion, haemorrhaging, and catarrhal inflammation of the gizzard lining, ulceration of the gizzard epithelium, degeneration of the koilin layer, and necrotic granulomas of the gizzard muscle.

Large infestations can interfere with the duck's digestive system and can cause weakness, weight loss and retarded growth. Sometimes the worm eggs can be seen in the duck's feces by the naked eye, but they more often require identification by conducting a fecal test.

Ducks become infected with gizzard worms through direct or indirect (through infected earthworms) ingestion of the nematodes.


Loss of appetite
Eggs found in feces
Stunted growth
Weight loss


  • History
  • Clinical signs
  • Fecal test
  • Necropsy


MethodMethod Summary
Management changesThe birds will just continue to get reinfected unless they are relocated to an alternate, non-contaminated site and better sanitary practices (such as daily cleaning) are conducted in order to reduce fecal build up.
Ivermectin0.2 mg/kg administered once orally as a single dose or subcutaneous injection
Flubendazole0.24 mg/kg feed administered in feed daily


  • Maintaining a clean habitat for waterfowl to live in
  • Avoid overcrowding
  • Routinely clean up bird feces



Risk Factors

  • Overcrowding
  • Poor sanitation
  • Unbalanced diet
  • Swans and geese are particularly susceptible

Also Consider