Parascaris equorum

(ascarid) roundworm of horses

*eggs are laid in small intestine-eggs are passed in feces-in soil infective larvae develop in the eggs in about 2 weeks- host ingests infective eggs-eggs hatch, larvae follow tracheal migration (liver-lungs-pharynx-reswallowed) and mature to adult stage in small intestine in about 2.5 months after infection.

Parascaris equorum

roundworm of horses

egg 

Strongyle egg

horse/or ruminant 

Strongyle adult

host: horses/ruminants

*adult nematodes live in cecum and large intestine-eggs are laid/passed in feces-eggs hatch and larvae develop to infective 3rd stage in soil and feces-host ingests infective larvae

*small stongyles=mature in large intestine

*large strongyle larvae penetrate the intestine and migrate extensively before maturing to adult stage 

Oxyuris equi

roundworm (pinworm) of horses 

*adult nematodes live in large intestine-female move to perianal area-eggs are deposited in clusters around the anus-larvae develop to infective stage in eggs in less then a week and may drop into food, bedding, or water-host ingests infective eggs- eggs hatch, release to the small intestine-and larvae mature to adult stage after migrating to the cecum and colon

*horses, rodents, and primates 

Oxyuris equi egg

pinworm of horses (rodents+primates) 

Gasterophilus spp. larvae

horse botflies 

*(nose bot fly(most damage), throat bot fly, and common bot fly)

*female attaches eggs to hairs-eggs hatch-larvae enter host via mouth and migrate to stomach-larvae attach to mucosa and grow-larvae detach and pass out in feces- pupae form in loose soil- adults emerge from pupae-adult flies copulate(do not feed)-cycle continues