Nematodes of the Equine Gut

Question 1

Trichostrongylus axei

Answer 1

hairworm of horses (pigs and ruminants too), live in the stomach, don’t cause very serious disease (diarrhea), seen with cograzing with cattle/ruminants

Question 2

Haebronema muscae

Answer 2

L3 larvae from the muscid fly, no effect in stomach (even though that is where development occurs)< problem is infestation of skin lesions, SUMMER SORES, often surrounded by eosinophils on histopath

Question 3

Habronema majus (microstoma) distribution

Answer 3

infects horses worldwide

Question 4

Draschia megastoma

Answer 4

equids worldwide, causes nodules on fundus of stomach, caseous abscesses

Question 5

Gasterophilus spp.

Answer 5

botflys!
G. intestinalis most common, the little yellow dots on horse are the eggs and they ingest them
rarely clinical but they crazy lookin

Question 6

Parascaris spp.

Answer 6

roundworm in horses (univalens most common, equorum rare), affects foals with worm burden peaking at 5 months, can cause impaction of small intestine, eventually immune system will clear infection (but can stunt growth or cause colic so)

Question 7

Is there correlation between fecal egg count and worm burden?

Answer 7

nope

Question 8

Strongyloides westeri

Answer 8

facultative parasite where only females are needed, causes SI enteritis (ingested) and dermatitis of distal extremities (percutaneous invasion), mild infection overall, mares become immune but are carriers, can be passed in milk

Question 9

3 Equine Cestodes

Answer 9

1. Anoplocephala perfoliata
2. Anaplocephala magna (rare)
3. Anoplocephaloides mamillana (rare)

Question 10

Intermediate host of A. perfoliata?

Answer 10

mites! they carry the cystercoid

Question 11

spasmodic colic

Answer 11

ADR

Question 12

Answer 12

A. perfoliata at the ileocecal valve

Question 13

cyathostomones

Answer 13

small strongyles (less common in US? weird)

Question 14

Can you differentiate small and large strongyles?

Answer 14

nope

Question 15

Strongylus vulgaris

Answer 15

large strongyles, affects horses worldwide, ingested larvae enter walls of cecum and colon and can migrate to the cranial mesenteric artery causing thrombosis/embolisms d/t granulation tissue

Question 16

3 Large Strongyles

Answer 16

1. Strongylus vulgaris
2. S. edentus (liver)
3. S. equinus (rare, peritoneal cavity)

Question 17

Oxyuris equi

Answer 17

pinworms!

females lay eggs around anus of horse (gelatinous gross material), very itchy, this is how horses get the bald tails

Question 18

Dictycaulus arnfieldi

Answer 18

lungworm, common in donkeys more than horses, migrate thru intestinal walls in lungs, secondary pneumonia possible

Question 19

Thelazia lacrymalis

Answer 19

eyeworm affecting horses and cattle, transmitted by face fly, causes excessive tear production and conjunctivitis, can see worms on eye

Question 20

Onchnocerca cervicalis

Answer 20

in bursa of nuchal ligament, can cause fibrosis/mineralization of ligament, and microsensitivity dermatitis

Question 21

culicoides

Answer 21

biting midges