Equine Parasite Control Flashcards
What are the goals of equine parasite control programs for neonatal and adults?
- Neonates: limit parasite burdens until young horses develop immunity
- Adults: minimize dz w/o inducing resistance to parasiticides
What are the major internal parasites that affect equines?
- Small Strongyles (Cyathostomes)
- seasonally transmitted
- winter in FL, summer in North
- Large Strongyles
- Anoplocephala perfoliata (Tapeworms)
- Ascarids - Parascaris equorum
- year round infection of young horses
What are minor internal parasites that affect equines?
- Gastrophilus intestinalis (Bots)
- Habronema muscae, Draschia megastoma (Stomach worms)
- Oxyuris equi (Pinworms)
- Strongyloides westeri (Threadworms)
- Dictyocaulus arnfieldi (Lungworms)
Describe small strongyles/cyathostomes
-
most important parasite to manage in adult horses
- sig concern for resistance in these populations
- prepatent period - min 5 wks
- larvae migrate in cecum/colon walls for 4-6 wks (may encyst for months to years)
- mature and encysted cyathostomes are not significant in causing dz if moderate #s
- Emergence of larvae –> intense inflammation –> hemorrhage and edema of cecum and colon –> colic and diarrhea
Describe large strongyles
- S. edentatus, S. equinus, S. vulgaris
- migrate thru abd tissues (liver, pancreas, arteries)
- live in the lumen of the gut
- long prepatent period (6 mo)
- C/S: colic, poor growth, wt loss
Describe parascaris equorum (roundworms)
- Adult horses develop immunity
- Eggs persist in environment for years
- Deadly for young foals
- Parasite lives in SI –> lymphatics –> liver –> lungs –> pharynx –> SI
- 28d to re-enter SI
- 72-80d to produce eggs
What are the clinical signs of an ascarid infection?
- Coughing
- Diarrhea, colic
- “Pot belly”
- Rough hair coat
- Wt loss
Cannot be diagnosed prior to 80-90d of infection by fecal float
How do you diagnose and control an ascarid infection?
- Dx: fecal float
- Tx: perform FECRT when possible, deworm at 60d of age (w/ ivermectin) or q 30d with pyrantel, benzimidizole until 8-12 mo of age
Describe Anoplocephala perfoliata (Tapeworms)
-
live at the ileo-cecal valve
- spasmodic colic
- intussusceptions
- ileal impactions
- Tx: Praziquantel, Pyrantel
- deworm foals prior to weaning, adults 1-2x per year
Describe the treatment for Gastrophilus intestinalis (Botflies)
- remove bot eggs from legs
- ivermectin or moxidectin
Describe Habronema, Drashcia spp (Stomach worms)
- transmitted by stable flies
- no sig internal damage
- cutaneous infections –> granulomas
- eyes, sheath, ventral midline
- tx w/ ivermectin
Describe oxyuris equi (pinworms)
- live in small colon
- female cements eggs to skin of anus
- prepatent period 3.5-5 mo
- dx problems:
- usually found as adult worms
- difficult to find on fecal float
Describe strongyloids westeri (threadworms)
- cause of diarrhea in foals (5d - 4mo)
- infection via milk
- stress of foaling induces larval activation in dam
- parasite resides in SI
- Immunity quickly developed (4-5 mo)
- Prepatent period 5-7d
- Tx mares in late gestation/foaling w/ macrocyclic lactones, tx foals as needed
Describe lungworms (dictocaulus arnfeldi)
- Donkeys can harbor infection w/ no CS
- Horses exposed parasite via donkeys
- cough
- decr performance
- tx w/ ivermectin
What are parasites of concern for the adult horse?
- small and large strongyles
- tapeworms
- gastrophilus
- oxyuris
