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Case Study 3: Arachnids in Small Animals

Itchy-Eared Rufus

Rufus is an adult mix-breed dog that has been exhibiting intermittent symptoms of otitis. He frequently shakes his head and paws at his ears. On examining Rufus, you detect a significant amount of a flakey brown material inside the pinna of each ear. Perceptive veterinarian that you are, you use a swab moistened with mineral oil to pick up the specimens seen at the case study station (see photo below) from Rufus' external ear canal and from the hair coat on the back of his head.

Otodectes cyanotis


1. What is your diagnosis of the cause of Rufus' otitis?

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2. What is the most likely route through which Rufus acquired this infestation?

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3. Does the finding of specimens outside the ear contradict your diagnosis?

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4. What drugs are approved by the FDA for therapy in this case? (Give the chemical [generic] name of the active compounds.)

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5. Is this parasite a threat to Fluffy (a cat) that shares the house with Rufus?

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6. Is this parasite a threat to Rufus' owners?

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Copyright © 2006 - University of Pennsylvania School of Veterinary Medicine, All rights reserved.
Faculty: Dr. Thomas Nolan
Students: Molly Church V'09, Diana Knight V'08, Douglas Gilson V'05, Chris Dykhouse V'04, Kimberly Mah V'00

Comments or Questions contact Dr. Tom Nolan at: