Attempted rescue of a great blue heron in Oklahoma
A great blue heron was brought into the Oklahoma State University Center for Veterinary Sciences Avian, Exotics and Zoo Medicine Department because it appeared extremely emaciated. While performing a general physical examination, the veterinarian discovered these organisms in the oral cavity.
Also, eggs of this type were recovered by fecal sedimentation (600X total magnification).
The bird was humanely euthanatized due to multiple health problems.
The organism was identified as Clinostomum marginatum based on host, where the adult worms were located, and morphology. This trematode, commonly called the “yellow grub”, is found in many freshwater fish in North America, which serve as the second intermediate host (the first intermediate host is the Helisoma sp. snail). Many aquatic bird species including herons can become infected by ingesting infected freshwater fish. Yellow grub adults parasitize the mouths and throats of birds. Fluke eggs are swallowed and passed in the feces of infected birds.
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