July 2012
Ticks in horses' ears
A seven-year-old Quarter Horse presented with head shaking and obvious duress. Examination of the ears under sedationrevealed these organisms. What is this parasite?
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Answer:
Otobius megnini, the spinose ear tick, is found in the ears of horses, cattle, dogs, cats, and occasionally people in the southwestern United States. These soft ticks are readily recognized by the presence of prominent spines on the cuticle, which are understandably irritating to the host. In severe infestations, neurologic signs may result. Only the larval and nymphal stages are parasitic; adults are free-living in the environment.
Otobius megnini, the spinose ear tick, is found in the ears of horses, cattle, dogs, cats, and occasionally people in the southwestern United States. These soft ticks are readily recognized by the presence of prominent spines on the cuticle, which are understandably irritating to the host. In severe infestations, neurologic signs may result. Only the larval and nymphal stages are parasitic; adults are free-living in the environment.