Elaeophora schneideri

Elaeophora schneideri is a roundworm that normally infects Mule and White-tailed Deer in the Southern United States and Rocky Mountain regions. It is also found in Europe, Africa, and Asia. Abnormal hosts include sheep, elk, moose, and goats.

Morphology
This is a slender worm. The female adults can be 60-120 mm and males are 55-85 mm long. The microfilaria are 239-279 micrometre μm and they are sheathed with a blunt tail.

Life cycle
The microfilaria are ingested by the tabanid fly during feeding. The L3 develop, then are released into the bite wound when the fly is feeding on the host. Worms develop and mature in carotid arteries and produce microfilariae in 4-6 months after infection. The adult worms embed in the blood vessel walls and live about 3-4 years.

Clinical signs
The worms do not cause any clinical signs in the normal hosts, however in the abnormal hosts there is facial dermatitis, lower limb dermatitis, horn deformities, necrosis of the muzzle, ears, and optic nerves, blindness, and death.

Diagnosis and treatment
Typical skin lesions, history, and location in an endemic area increase suspicion of E. schneideri. Upon necropsy, adult worms can be found in the carotid arteries.

Repeated administration of diethylcarbamazine, risk of fatality from presence of dead worms in the arteries.