Unit 3 Parasites

Gasterophilus intestinalis common name:

Common horse bot

Gasterophilus intestinalis phylum/class:

Arthropod/ Insect

Location of Gasterophilus intestinalis:

-Eggs on skin (forelegs, belly, flank)

-3rd instar in stomach

Gasterophilus intestinalis life cycle:

-Adult fly lays eggs on horse’s hair

-Horse licks eggs or eggs hatch and burrow into tongue or gingiva and mature

-Larvae migrate to stomach and overwinter 

-Bots passed in feces in spring where they pupate

-Adults emerge 3-10 weeks later

Gasterophilus intestinalis clinical signs:

Sores in mouth, GI hemorrhage/ulceration, anorexia, colic, or no signs

Gasterophilus intestinalis diagnosis:

Necropsy, observe eggs on hair, ulcers in mouth

Gasterophilus intestinalis treatment:

Ivermectins or remove eggs from hair 

Is Gasterophilus intestinalis zoonotic:

No

Gasterophilus nasalis common name:

Chin/throat bot

Gasterophilus nasalis phylum/class:

Arthropod/ Insect

Location of Gasterophilus nasalis:

Eggs on skin (under chin), 3rd instar in stomach

Gasterophilus nasalis lifecycle:

-Adult fly lays eggs on horse’s hair

-Horse licks eggs or eggs hatch and burrow into tongue or gingiva and mature

-Larvae migrate to stomach and overwinter 

-Bots passed in feces in spring where they pupate

-Adults emerge 3-10 weeks later

Gasterophilus nasalis clinical signs:

Sores in mouth, GI hemorrhage/ulceration, anorexia, colic, or no clinical signs

Gasterophilus nasalis diagnosis:

Necropsy, observe eggs on hair, ulcers in the mouth

Gasterophilus nasalis treatment:

Ivermectins or remove eggs from hair

Is Gasterophilus nasalis zoonotic:

No

Gasterophilus hemorrhoidalis common name:

Chin/ throat bot 

Gasterophilus hemorrhoidalis phylum/class:

Athropod/ insect

Location of Gasterophilus hemorrhoidalis:

Eggs on skin (around lips/nose), 3rd instar in the stomach

Gasterophilus hemorrhoidalis life cycle:

-Adult fly lays eggs on horse’s hair

-Horse licks eggs or eggs hatch and burrow into tongue or gingiva and mature

-Larvae migrate to stomach and overwinter 

-Bots passed in feces in spring where they pupate

-Adults emerge 3-10 weeks later

Gasterophilus hemorrhoidalis clinical signs:

Sores in mouth, GI hemorrhage/ulceration, anorexia, colic, or no clinical signs

Gasterophilus hemorrhoidalis diagnosis:

Necropsy, observe eggs on hair, ulcers in mouth 

Is Gasterophilus hemorrhoidalis zoonotic:

No

Gasterophilus hemorrhoidalis treatments:

Ivermectins or remove eggs from hair

Habronema spp. common name:

-Summer sores

-Bursati

-Granular dermatitis

Habronema spp. phylum:

Nematode

Location of adult: Habronema spp.

Skin or stomach

Habronema spp. life cycle:

-Flies eat larvae

-Larvae develop and move to fly mouthparts and get deposited on lips, nostrils, or wounds

-Larvae move to stomach and produce fibrous tumors or enter skin and create chronic draining sores

Habronema spp. clinical signs:

Minimal, but can obstruct GI outflow or itchy, hemorrhagic wounds

Habronema spp. diagnosis:

Necropsy or biopsy of wounds

Habronema spp. treatment:

-Ivermectins for skin issues

-Difficult to treat gastric tumors

Is Habronema spp. zoonotic:

No

Strongyloides westeri common name:

Equine Threadworm

Strongyloides westeri phylum:

Nematode

Location of Strongyloides westeri:

Small intestine

Strongyloides westeri life cycle:

-L3 penetrate skin

-Passed in milk or eaten

-Then tracheal or mucosal migration to small intestine

Strongyloides westeri clinical signs:

Generally in young foals, diarrhea as young as 9 days of age

Strongyloides westeri diagnosis:

Larvae in mare’s milk or embryonated eggs in fresh feces of foal

Strongyloides westeri treatment:

Ivermectin and FenbendazoleI

Is Strongyloides westeri zoonotic:

No

Parascaris equorum common name:

Equine ascarids/roundworms

Parascaris equorum phylum:

Nematode

Location of Parascaris equorum:

Small intestine

Parascaris equorum life cycle:

-Eggs passed in feces and consumed

-Tracheal migration 

-Get to small intestine and produce eggs

Parascaris equorum clinical signs:

Respiratory signs in young foals before PPP, colic, dull hair coat, undersized after PPP

Parascaris equorum diagnosis:

ID eggs in fecal float

Parascaris equorum treatment:

Benzimidazoles, Pyrantel, Ivermectin

Is Parascaris equorum zoonotic:

No

Stongylus vulgaris/ S. edentatus/ S. equinus common name:

Large Strongyles 

Stongylus vulgaris/ S. edentatus/ S. equinus phylum:

Nematode

Location of Stongylus vulgaris/ S. edentatus/ S. equinus:

Cecum and colond

Stongylus vulgaris/ S. edentatus/ S. equinus life cycle:

-L3 ingested and penetrate SI wall molt and penetrate arterioles

-Migrate to cranial mesenteric artery

-Migrate to submucosa of cecum and colon

-Pass strongyle type eggs

Stongylus vulgaris/ S. edentatus/ S. equinus clinical signs:

Colic, diarrhea, exercise intolerance, thromboembolic colic, rear-limb weakness, death

Stongylus vulgaris/ S. edentatus/ S. equinus diagnosis:

ID eggs in fecal float, Baermann to ID larvae, necropsy

Stongylus vulgaris/ S. edentatus/ S. equinus treatment:

Ivermectin

Is Stongylus vulgaris/ S. edentatus/ S. equinus zoonotic:

No

Cyathostomes common name:

Small Strongyles

Cyathostomes phylum:

Nematode

Location of Cyathostomes:

Small intestine, large intestine, cecum

Cyathostomes life cycle:

-L3 ingested and penetrate intestinal mucosa or encyst

-Move to intestinal mucosa

-Eggs passed in feces

Cyathostomes clinical signs:

Diarrhea, colic, weight loss, death

Cyathostomes diagnosis:

ID eggs in fecal float, Baermann to ID larvae

Cyathostomes treatment:

Avermectins, manage pastures 

Is Cyathostomes zoonotic:

No

Anoplocephala perfoliata common name:

Medium horse tapeworm

Anoplocephala perfoliata phylum/class:

Platyhelminth/ cestode

Location of Anoplocephala perfoliata:

Small intestine, cecum, colon

Anoplocephala perfoliata life cycle:

-Proglottids passed in feces and ingested by orbatid mite

-Horse eats mite

-Tapeworm develops in horse

Anoplocephala perfoliata clinical signs:

None to death depending on parasite load

Anoplocephala perfoliata diagnosis:

ID eggs in fecal float, necropsy, physical exam

Anoplocephala perfoliata treatment:

Praziquantel

Is Anoplocephala perfoliata zoonotic:

No

Anoplocephala magna common name:

Large horse tapeworm

Anoplocephala magna phylum/ class:

Platyhelminth/ cestode

Anoplocephala magna life cycle:

-Progllottids passed in feces and ingest by orbatid mite

-Horse eats mite

-Tapeworm develops in horse

Anoplocephala magna clinical signs:

None to death depending on parasite load

Anoplocephala magna diagnosis:

ID eggs in fecal float, necropsy, physical exam

Anoplocephala magna treatment:

Praziquantel 

Is Anoplocephala magna zoonotic:

No

Paranoplocephala mamillana common name:

Dwarf tapeworm of the horse

Paranoplocephala mamillana phylum/ class:

Platyhelminth/ cestode

Location of Paranoplocephala mamillana:

Small intestine, cecum, colon

Paranoplocephala mamillana life cycle:

-Proglottids passed in feces and ingested by orbatid mite

-Horse eats mite

-Tapeworm develops in horse

Paranoplocephala mamillana clinical signs:

None to death depending on the parasite load

Paranoplocephala mamillana diagnosis:

ID eggs in fecal float, necropsy, physical exam

Paranoplocephala mamillana treatment:

Praziquantel

Is Paranoplocephala mamillana zoonotic:

No

Oxyuris equi common name:

Pinworm/ Oxyurids

Oxyuris equi phylum:

Nematode

Location of Oxyuris equi:

Cecum, colon, rectum

Oxyuris equi life cycle:

-Horse eats egg

-Mucosal migration

-Female worm migrate to anus and lays eggs on perianal skin

Oxyuris equi clinical signs:

Rat tail, off feed, restless, sometimes no clinical signs

Oxyuris equi diagnosis:

Physical exam. cellophane tape test

Oxyuris equi treatment:

Pyrantel

Is Oxyuris equi zoonotic:

No

Dictyocaulus arnfieldi common name:

Equine Lungworm

Dictyocaulus arnfieldi phylum:

Nematode

Location of Dictyocaulus arnfieldi:

Bronchi

Dictyocaulus arnfieldi life cycle:

-Horse eats larvae

-Migration to lungs occurs via lymph and blood systems to bronchi

-Adult lays eggs that are coughed up and swallowed

Dictyocaulus arnfieldi clinical signs:

Increased RR, nasal discharge, coughing