Horse (some cow) Parasites

Question 1

trichostrongylus axei in horses causes what

Answer 1

chronic gastritis

Question 2

this is the egg of what parasite found in foals?

Answer 2

Strongyloides westeri

prevent this by treating the mom with ivermectin since it is passed via the milk

Question 3

explain life cycle of hypoderma/warble flies

Answer 3

adults do not live on the animal. females lay eggs on the hair of cows, larva hatch and penetrate the skin, and migrate into tissues for winter. in late winter they migrate to the subQ tissues of the back and perforate thru the skin, then they drop to the ground and mutate

Question 4

you see a horse with this lesion. it is the summer time and you think it might be habroemiasis. what else could this be?

Answer 4

infectious granuloma, eosiniphilic granuloma, SCC, sarcoid, proud flesh

Question 5

summer sores often resolve by the end of summer, but what is the best way to prevent it next summer?

Answer 5

regular deworming with ivermectin or moxidectin. fly control and removal of manure also helps

Question 6

a horse rescue calls you in July because many of their horses have “big red sores” on them. When you ask where the sores are, they tell you there are sores in many places: the corners of the eyes, the nostrils, the vulva, the teats, and the corners of the mouth. You ask if the horses are itchy and they say two of the 10 horses affected seem very itchy. ddx? how do you want to diagnose this?

Answer 6

habronemiasis

diagnose: deep scraping or smears from the tissues, or a biopsy

Question 7

describe the life cycle of screw worm

Answer 7

female fly lays eggs in moist environments or lacerations, including umbillicus of calves/foals, castration sites, etc. Larva hatch and eat the live tissue. this can be fatal

Question 8

this is the egg of what parasite found in foals?

Answer 8

Parascaris equorum, this causes colic via intestinal impaction.

Question 9

“bull’s eye”” lesion on top of the head of a horse is

Answer 9

onchocera

Question 10

gastrophilus intestinalis is

Answer 10

the horse stomach botfly

Question 11

reguarding horse parasites, 50 years ago the main wrom of concern was _____, but now the main worm of concern is _____

Answer 11

50yrs ago: large strongyles (strongylus vulgaris)

now: small strongyles (cyathastomins

Question 12

what is the main internal parasite we need to worry about when it comes to adult horses?

Answer 12

small strongyles/cyathastomins

Question 13

which room hangs out in the root of the cranial mesenteric artery and causes a thromboembolism and colic?

Answer 13

strongylus vulgaris

Question 14

anoplocephala perfoliata is what kind of worm in the horse?

Answer 14

tapeworm

Question 15

large roundworms in foals (parascaris univalens) live where?

Answer 15

in the small intestine (portal and lung migration), and they are quite large so can cause colic

Question 16

Now a days, what is the main worm of concern for adult horses?

Answer 16

small strongyles (cyathostomins)

Question 17

Onchocerca cervicalis is spread via

Answer 17

culicoides midges

Question 18

50 years ago the main worm of concern for adult horses was ____ and for foals was _____

Answer 18

adults: large strongyles, strongylus vulgaris
foals: parascaris

Question 19

ascarids (parascaris equorum/univalens) are probably an issue for which group of horses?

Answer 19

foals (adults have immunity)

Question 20

briefly describe the life cycle of cyathostomins (small strongyles)

Answer 20

adults in large intestine, eggs pooped out, L3 ingested from pasture, larva penetrate mucosa, can be dormant, emerge from the walls as adults

Question 21

“warbles” is what disease

Answer 21

hypoderma

Question 22

describe the life cycle of habronemiasis

Answer 22

adult worms in the stomach, eggs and larva are pooped out, the maggots of flies ingest the larva in the horse poop, (usually house fly or stable fly), larvae grow up to L3 in the fly, flies then go to moist areas and deposit L3 into tissue and they migrate locally. the horse then ingests them, either by itching or by flies depositing larva near the mouth

Question 23

moroccan leather of the abomasum happens due to what parasite

Answer 23

ostertagia

Question 24

a horse rescue calls you because some horses have alopecia, crusting, itchy lesions along ventral midline and around the neck. you suspect ??? and want to do a ??? to confirm

Answer 24

onchocera, biopsy

Question 25

“summer sores” is the dumb man term for

Answer 25

habronemiasis

Question 26

what is the main internal parasite we need to worry about when it comes to foals and yearlings?

Answer 26

parascaris univalens/large roundworms

oxyuris equi: pinworms (can happen in adults too)

strongyloides westeri/threadworms for foals less than 6 months of age

Question 27

explain difference between ostertagi type I and ostertagi type II disease

Answer 27

type I: grazing calves eat L3 and they burrow into glands in abomasum then emerge as adults, usually late summer/fall
type II: when the larvas freeze in the L4 stage and hang out all winter long and in Feb-May they all resuke their deveopment at the same time

Question 28

explain a brief life cycle for Onchocerca cervicalis

Answer 28

adult worms live in nuchal ligament, females produce larva which migrate thru the skin of the face or ventral midline. midges then bite the skin and the larva develop into L3 inside the midge. when the midge bites the horse again is when the L3 infective larvae enter the horse again.

Question 29

warble flies are significant because they

Answer 29

cause hide damage

Question 30

what is “acute larval cyathostominosis”

Answer 30

mass emergence of inhibited larva