Dictyocaulus arnfieldi is not known to be zoonotic.
The closest relatives of D. arnfieldi are the lungworms D. viviparus of cattle and D. filiaria of sheep, all of which have similar life cycles.
Adult D. arnfieldi measure up to approximately 3.5 cm (males) and 6.0 cm (females) in length. The males have a distinct copulatory bursa and short, thick spicules.
The larvated eggs of D. arnfieldi (the stage passed in feces) measure up to approximately 100 μm by 60 µm, and contain a first-stage larva when freshly passed.
Host range and geographic distribution
Life cycle - direct
Life Cycle: Dictyocaulus arnfieldi
Pathology and clinical signs
Treatment and control
No products are approved in Canada for treatment of Dictyocaulus arnfieldi in horses or donkeys, but extralabel ivermectin and possibly fenbendazole may be effective.
Additional information on the product mentioned is available from the Compendium of Veterinary Products (Twelfth Edition, 2011), or from the manufacturers.
Control of D. arnfieldi in horses depends most importantly on preventing contact at pasture between horses and donkeys and other hosts in which the parasite may be patent.