August 2017

Meet Virginia

An opossum was found dead in eastern Oklahoma and submitted for necropsy. Several of these nematodes were present in the cecum (see below).​​​

Additionally, a fecal flotation was performed on fecal material collected from the colon. See the photomicrograph of the flotation below. The egg of interest is marked by a blue star:  

What is your diagnosis?

Many thanks to Kathryn Duncan, 4th year veterinary student at the University of Tennessee for providing case content and photographs.

Answer

This is Cruzia americana, the pinworm of Virginia opossums (Didelphis virginiana). A common parasite of opossums, this nematode normally resides in the cecum but can migrate to other regions of the intestinal tract once the host dies. In large numbers, this parasite can cause diarrhea, malabsorption, and debilitation. Similar to the horse pinworm, Oxyuris equi, adult C. americana have a long tapering tail and an esophageal bulb. Cruzia americana eggs measure 110 by 66 micrometers, and they can be found in dog feces if the dog ingests an infected opossum or its feces; pinworms are host specific so this would be considered a spurious parasite if found in dog feces