November 2022

​Oh deer!

​A white-tail deer from a Northeast Oklahoma farm, was submitted for necropsy to the Oklahoma Diagnostic Laboratory during the month of August 2022. During necropsy the following larva was found on the esophagus. 

Images 1-3: Larva found in the esophagus
Images 4-5: Posterior spiracles of recovered larva

What's your diagnosis?

Hypoderma lineatum, also called heel flies or gadflies. The adult flies deposit eggs on the hair of cattle, deer and sometimes horses. The eggs hatch within a week and migrate through the connective tissues of the host. The larva of H. lineatum accumulate in the esophagus during migration and remain there for about 3 months. After, they migrate to the subcutaneous tissues of the back, forming lumps or warbles and cutting breathing holes in the skin of the host. When the larva emerges from the warble they measure approximately 25 mm long with a light brown color.