Other Equine Parasites Flashcards
What cestodes affect horses?
Anoplocephala perforliata
Anocephala magne
Paranplocephala mamillana
What are the characteristics of tapeworms?
Adult parasites found in small intestines
Indirect life cycle- in this case involves an oribatid mite (free living forage mite) as the intermediate host
Metacestode stage found in the intermediate host is a cysticercoid
What is the most common, significant species of tapeworm?
Anocephala perfoliata
Describe the appearance of anocephala perforliata?
Adults found at the ileo-caecal junction
Short, broad segments
Lappets behind each of four suckers
How can you distinguish between A. perforliata, A. Magna and P. mamillana?
A. perforliata- lappets behind each of four suckers
A. magna- no lappets
P. mamillana- two suckers
Describe the life cycle of A. perforliata
- Adult tapeworm at ileo-caecal junction
- Proglottids passed in faeces, disintegrate and eggs release
- Eggs ingested by free-living orbatid mites and develop to cysticercoid
- Infected mite ingested by horse
- 2 months from ingestion of mite to presence of tapeworm
Where are orbitatid mites- carriers of cysticeroids of A. perforliata found?
Found in soil, shavings, hay
Common, ubiquitous
Microscopic
What does this image show?
Egg of A. perfoliata (right) compared to a strongyle egg (left)
Eggs of A. perfoliata irregularly shaped (D-shaped)
Oncoshpere supported by pyriform apparatus
Describe the pathogenesis of A. perfoliata
Adults at the ileo-caecal junction
Causes-
Spasmodic colic, intussusception, ileal impaction, rupture
What are the clinical signs of A. perfoliata infection?
Ulceration and pathological changes in intestine
Unthriftiness
Enteritis
Colic
What ages of horse are affected by A. perfoliata and when does the infection level peak?
All ages infected- highest in <3yo
Peaks in autumn/winter- always possible
How is A. perfoliata diagnosed and controlled?
Eggs in faeces- FEC
ELISA for circulating antigen- IgG
EquiSal saliva test
Treatment/control- Double dose pyrantel, Praziquantel
What families of nematodes affect horses?
Stronglyes
Parascaris equorum
Oxyuris equi
Describe the general appearence and location of ascarid nematodes?
Large, white roundworms
Adults in small intestine
What are the general features of ascarid nematodes?
- Females lay large numbers of eggs
- Eggs are highly resistant
- L2 larvae develop in egg
- L2 in egg is infective stage
- Direct life cycle
- Hepato-tracheal migration
- Migrating larvae stimulate inflammatory response
- Adult worms browse on intestinal contents
- Adult worms can cause blockage
- No damage to mucosa
What species of ascarid nematodes affects horses and donkeys and describe their life cycle
Parascaris equorum-
Eggs passed in faces
Develop on ground- temp dependent
Egg containing L2 eaten
L2 migrates to liver- lung- L2-L3
Coughed up, swallowed, L4-L5 in SI
PPP- 12 weeks
What age of horse does Parascaris equorum affect and what are the symptoms?
Typically foals
Transient cough
Poor weight gain
No diarrhoea
Possible obstruction in heavily infected individuals
How is Parascaris equorum (carbonara) controlled?
Foal to foal infection- adults immune
Eggs resistant- anthelmintic resistance
Drug resistance reported to- Ivermectin and moxidectin
What parasite and egg is shown in this image?
What is its name and common name?
Oxyuris equi
Horse pinworm
Describe the appearance of oxyuris equi and what is an infection commonly refered to as?
Adult worms are 1-10 com and have pointed tails
‘Anal rust’
Describe the life cycle of Oxyuris equi and what is the PPP?
- Direct
- Female lay eggs on peri-anal skin
- Eggs fall to ground
Develop to L3 in egg - Ingested
- Larve develop in mucosap crytpes in LI
- Adults in lumen of LI
PPP- 5 months
Oxyuris equi- What are the clinical signs, how is it diagnosed and controlled?
Clinical signs- prutitis, excoration (tail) [urge to constantly itch]
Diagnosis- eggs on peri-anal area, sellotape test
Control-
Anthelmintics- but can be a challenge due to lack of efficacy/rapid reinfecton
High hyigene environments reduces transmission
