New Year's fun findingA 2-year-old female mule deer (Odocoileus hemionus) from western Oklahoma was submitted to the Oklahoma Animal Diseases Diagnostic Laboratory, for necropsy. During examination the following specimens were recovered from the cervical region.  Image 1: Adult nematode recovered from the cervical region of a deer Eleaphora shneideri female (F) and male (M), not associated to the cause of death in this case. (Image 2 and Image 3)
Image 2: Anterior end
Image 3: Posterior end of male nematode with cuticular thickenings (red arrow) and spicules (black arrow) These nematodes are common parasites of mule deer and deer in the US. Adults live in the carotid arteries or their branches; females measure an average of 10 cm and males 7 cm.
E. shneideri are transmitted by Tabanid flies considered cyclodevelopmental hosts. Infective larvae migrate to the leptomeningeal arteries where they develop into young adults and further migrate to the carotid or maxillary arteries where they become adults, releasing microfilariae (average 250 µm in length) into the bloodstream. (Images 4-6). In mule deer E. shneideri is often asymptomatic, in sheep it can cause dermatitis of the head as a reaction to the microfilariae in the skin, also referred as “sore head”. In other atypical hosts such as moose or elk they can develop clinical eleaphorosis, characterized by obstructed blood flow, thrombosis and endothelial damage. Image 4: Microfilaria Image 5: Anterior end of microfilaria Image 6: Posterior end of microfilaria |
