Cochlosomiasis ( Cochlosoma anatis ) in Turkeys and Ducks
By light microscopy, Cochlosoma anatis is 6–12 micrometers (mcm) long and 4–7 mcm wide, with a characteristic adhesive disc on the anteroventral surface of its pyriform body. It moves in a jerking motion. This protozoan has a single nucleus and uses flagella for movement. Lateral transmission has been observed with turkeys, but direct contact of the birds was necessary for infection. PCR has detected C anatis on house flies, but no studies have demonstrated them as carrying live trophozoites.
There is a debate on the pathogenicity of C anatis in avian species. The exact role of this parasite is unknown, because coinfection of viruses, bacteria and other protozoans with C anatis has led to gastrointestinal distress whereas infection with this protozoan alone does not always lead to clinical signs. Scanning electron microscopy has shown C anatis attaching to intestinal mucosa; however, no visual changes in the intestines have been observed under light microscopy with the protozoan present.
Wild birds, small rodents, and multi-aged flocks have been identified as carriers of C anatis. Proper biosecurity prevents the entry of this parasite to poultry flocks. Disinfection of housing facilities after an outbreak is necessary to prevent contamination of future flocks. Nitroimidazole and nitarsone have been proven as successful treatments for C anatis, but unfortunately these products are not approved in commercial poultry.