Other equine parasites

Question 1

Tapeworms belong to which family?

Answer 1

Anoplocephalide

Question 2

Name the tapeworm spp of horses

Answer 2

Anoplocephala perfoliata

Question 3

Where are adult Anoplocephala perfoliata found in the horse?

Answer 3

Ileo-caecal junction

Question 4

Describe the eggs of Anoplocephala perfoliata?

Answer 4

• 60-80um
• D-shaped
• Onchosphere supported by pyriform apparatus

Question 5

Describe the morphology of Anoplocephala perfoliata

Answer 5

• Short, broad segments – not long tapeworms

- Lappets behind each of four suckers

Question 6

Describe the life cycle of Anoplocephala perfoliata

Answer 6

• Adult at ileo-caecal junction
• Proglottids passed in faeces which release eggs
• Eggs ingested by free living oribatid mites
• Infected mites ingested by horse

Question 7

How long does it take from ingestion by the horse to the presence of an adult tapeworm?

Answer 7

2 months

Question 8

Describe the pathology of disease with Anoplocephala perfoliata

Answer 8

Spasmodic colic, intussusception, ileal impaction, rupture

Question 9

What are the clinical signs of Anoplocephala perfoliata infection?

Answer 9

• Ulceration and pathological changes in intestine
• Unthriftiness – dull coat/appearance, underweight
• Enteritis
• Colic

Question 10

How is Anoplocephala perfoliata diagnosed?

Answer 10

• Eggs in faeces – FEC (~60% sensitivity)

- ELISA to detect circulating antigen (68% sensitivity, 95% specificity)

Question 11

How is Anoplocephala perfoliata treated?

Answer 11

• Double dose pyrantel

- Praziquantel

Question 12

What are some of the main features of ascarid nematodes in horses?

Answer 12

• Large, white roundworms
• Adults in small intestine
• Direct life cycle
• Hepato-tracheal migration
• Eggs are highly resistant – thick surrounding wall which allows L2 to develop inside and protects them for years

Question 13

What is the infective stage of ascarid nematodes?

Answer 13

L2 in the egg

Question 14

Describe the life cycle of Parascaris equorum

Answer 14

• Eggs passed in faeces
• Develop on the ground – temp dependent ~4 weeks
• Egg (containing L2) eaten by horse
• L2 migrates to liver, then to the lung (L2-L3)
• Coughed up, swallowed, L4-L5 (adult) in small intestine

Question 15

What is the PPP of Parascaris equorum?

Answer 15

12 weeks

Question 16

Describe the disease of Parascaris equorum and its signs

Answer 16

• Typically affects foals
• Transient cough
• Poor weight gain, unthrifty
• No diarrhoea
• Possible obstruction in heavily infected individuals

Question 17

How can Parascaris equorum be controlled and treated?

Answer 17

• Foal to foal infection
• Adults immune
• Eggs are resistant and long lived
• Anthelmintic treatment = Fenbendazole or pyrantel

Question 18

What is the name given to the horse pinworm?

Answer 18

Oxyuris equi

Question 19

Describe the morphology of Oxyuris equi adults

Answer 19

• Pointed tails
• 1-10cm
  • Females larger
  • Males – 1cm

Question 20

Describe the morphology of Oxyuris equi eggs

Answer 20

Eggs - 80μm

Have a single mucoid plug at one end

Question 21

How does Oxyuris equi cause ‘anal rust’?

Answer 21

Females lay their eggs around the anus in a sticky fluid to adhere them

Question 22

Describe the life cycle of Oxyuris equi

Answer 22

• Direct
• Female lays eggs on peri-anal skin
• Eggs fall to the ground
• Develop to L3 in the egg
• Ingested
• Larvae develop in mucosal crypts in large intestine
• Adults in lumen of large intestine

Question 23

What is the PPP of Oxyuris equi?

Answer 23

5 months

Question 24

What are the clinical signs of Oxyuris equi?

Answer 24

Pruritis

excoriation (tail)

Question 25

How can Oxyuris equi be diagnosed?

Answer 25

• Eggs on peri-anal area

- Sellotape/Scotchtape test

Question 26

How can Oxyuris equi be controlled?

Answer 26

• Anthelmintics- but can be a challenge due to lack of efficacy/rapid reinfection
• High hygiene environments reduces transmission
• Wash around the anus 2x a day