Prosthogonimus macrorchis

Prosthogonimus macrorchis, commonly referred to as the oviduct fluke, is a type of flatworm parasite that invades the bird's oviduct. They are found in chickens, geese, ducks, turkey, and other domestic and wild birds. They are widespread and found often in humid environments such as wetlands, swamps and marshes. The disease caused by Prosthogonimus flukes is called prosthogonimiasis. These parasites can be very harmful for free range flocks that live in humid environments. P. macrorchis can cause severe infections in hens, as they damage the bird's oviduct tissues which can result in inflammation, often leading to peritonitis and/or secondary invasion with bacteria that can worsen the infection.

P. macrorchis produces small, oval eggs that are less than 15x25 micrometers.

Life cycle
P. macrorchis has a complex, indirect life cycle, which uses two intermediate hosts---the freshwater snail and dragonflies. Birds become infected by consuming both the contaminated dragonflies or snails.

Signs of infection include
  • Bright green colored droppings, which sometimes may contain flukes
  • Pasting (soiling) of vent feathers
  • Loss of appetite
  • Restlessness
  • Increased thirst
  • Difficulty breathing
  • Walk abnormally
  • Tense and hot abdomen

Treatment options
There are reports that praziquantel (5 to 10 mg/kg) and mebendazole (10 to 50 mg/kg) may be effective.


  • chickens
  • ducks
  • turkeys
  • wild birds
  • geese

Associated Diseases