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Modern poultry production methods have diminished the incidence of fluke infections, although the parasites persist in poultry allowed contact with snails or other hosts, and in some wild birds.
Prosthogonimus macrorchis, the oviduct fluke of poultry, infects birds after they consume infective metacercariae in developing or mature dragonflies, the secondary host. The piriform fluke matures in ~2 wk in the bursa of Fabricius or, in gallinaceous birds without a functional bursa (eg, chickens, turkeys, pheasants), in the oviduct.
Light infections without clinical signs appear in ducks and other birds with a functional bursa. In gallinaceous birds, heavy infections in the oviduct cause inappetence, droopiness, weight loss, calcareous cloacal discharge, and depressed egg production (the eggs being soft-shelled). Lesions range from mild inflammation to distention or rupture of the oviduct due to exudate and egg components; death may result. Diagnosis by fecal examination is unreliable because fluke eggs are not consistently present. Adult flukes may appear in the bird's eggs or be found in the oviduct on necropsy.
To prevent fluke transmission, birds must be kept from feeding on dragonflies. There is no effective treatment approved for use in poultry. Carbon tetrachloride, is highly toxic to birds, especially chickens.
Collyriclum faba appear as subcutaneous cysts 4-6 mm in diameter (usually containing 2 adults) anywhere on the body but more frequently near the vent in turkeys, chickens, and other birds. The cysts ooze exudate, which attracts flies and predisposes to bacterial infection. Signs in young birds include locomotor difficulty and inappetence; death may result in heavy infections. The parasites can be removed surgically. The life cycle is unknown but probably involves snails and insects such as dragonflies or mayflies. Prevention of infection requires restricting birds from areas frequented by aquatic insects.
See Also:
Ascites Syndrome
Breast Blisters
Cannibalism
Gout
Pendulous Crop
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