Large Animal Internal Parasites- Equine

Parascaris equorum- Common Name

Roundworm
of horses

Parascaris equorum- Definitive Host

Horse

Parascaris equorum- Life Cycle

Direct=> Eggs pass in feces=> second stage within egg => ingested by horse in food or water/licking=> eggs hatch release larvae to undergo tracheal migration=> penetrate intestinal wall=> migrate through portal vein to liver and lungs=> coughed and swallo

Parascaris equorum- Location in host

cranial portion of small intestine- duodenum

Parascaris equorum- Infective Stage

embryonated eggs

Parascaris equorum- Diagnostic Stage

eggs in feces/ adult worms in feces

Strongylus edentatus, S. equinus, S. vulgaris- Common Name

Large Strongyles or Strongyles

Strongylus edentatus, S. equinus, S. vulgaris- Definitive Host

Horses and Donkeys

Strongylus edentatus, S. equinus, S. vulgaris- Prepatent Period

8-10 months

Strongylus edentatus, S. equinus, S. vulgaris- Life Cycle

Eggs hatch 1-2 days=> L2 molts in one week=> L3 infects via ingestion during grazing => L3 in stomach and penetrates gut wall=> molts to L4=> L4 migrates for months until attaching to wall of cecum and large intestine

Strongylus edentatus, S. equinus, S. vulgaris- Diagnostic Stage

Eggs in feces, contains 20 cells

Strongylus edentatus, S. equinus, S. vulgaris- Infective Stage

L3 on vegetation

Strongylus edentatus, S. equinus, S. vulgaris- Location in Host

Cecum and large intestine- blood sucking

Small Strongyles- Definitive Host

Horse and Donkey

Small Strongyles- Life Cycle

eggs pass in feces=> hatch=> develop to third stage=> migrate up grass=> ingested by horse=> L3 infective in stomach and forms nodules=> enters cecum and colon=>develop and molt => return to lumen as L5

Small Strongyles- Infective Stage

L3 on vegetation

Small Strongyles- Prepatent Period

4 weeks - 4 months

Small Strongyles- Diagnostic Stage

Eggs in feces

Oxyuris Equi- Common Name

pinworm

Oxyuris Equi- Definitive Host

Horse and Donkey

Oxyuris Equi- Prepatent Period

4-5 months

Oxyuris Equi- Life Cycle

eggs from perianal region=> rubbed off=> direct host ingests=> small intestine=> cecum and feed on mucosa

Oxyuris Equi- Infective Stage

eggs containing larvae

Oxyuris Equi- Diagnostic Stage

Scotchtape test around anus

Strongyloides westeri- Common Name

Threadworm

Strongyloides westeri- Definitive Host

Horse and Donkey

Strongyloides westeri- Life Cycle

L3 enters host via penetration of skin=> larvae migrate through tissues=> include alveoli of lungs=> reach intestine by ascending trachea=> swallowed and travel to GI tract=> intestine the juveniles migrate to the mucosa where they develop to adults

Strongyloides westeri- Diagnostic Stage

Embryonated eggs and larvae

Strongyloides westeri- Infective Stage

L3 penetrate skin

Anoplocephala magna, A. perfoliata, Paranophocephala mammillana- Common Name

Tapeworm

Anoplocephala magna, A. perfoliata, Paranophocephala mammillana- Definitive Host

Horse and Donkey

Anoplocephala magna, A. perfoliata, Paranophocephala mammillana- Life Cycle

Indirect-
Embryonated eggs hatch in orbatid mites=> develop into cysticercoid when horses engest mites=>

Anoplocephala magna, A. perfoliata, Paranophocephala mammillana- Diagnostic Stage

embryonated eggs

Anoplocephala magna, A. perfoliata, Paranophocephala mammillana- Infective Stage

cysticercoids in infected folage, usually through the mite on grass

Equine Cestodes

Anoplocephala magna,
A. perfoliata,
Paranophocephala mammillana

Eimeria leukart- Definitive Host

Horse and Donkey

Eimeria leukart- Life Cycle

Direct

Eimeria leukart- Diagnostic Stage

oocyst in feces
very large for coccidia, brwn thick walled with openings on narrow end

Eimeria leukart- Diagnostic Test

Fecal Sedimentation or Fecal Flotation- sugar flotation solution required

Eimeria leukart- Infective Stage

sporulated oocyst

Protozoan of Horses and Donkeys

Eimeria leukart