6

Question 1

Tapeworm. The most common tapeworm in horses is in the genus

Answer 1

Anoplocephala.

Question 2

, is called the “large horse tapeworm” and occurs most often in the
small intestine. It also is found in the stomach and sometimes in the cecum.

Answer 2

Anoplocephala magna

Question 3

Stomach Worms
The habronemas, which consist of

Answer 3

consist of Habronema muscae, H. majus, and H. megastoma (Draschia
megastoma), are the equine stomach worms

Question 4

equine stomach worms that cause two rather distinct diseases in horses:

Answer 4

gastric and
cutaneous habronemiasis

Question 5

have indirect life cycles, with house and stable flies serving as
intermediate hosts.

Answer 5

Habronemas

Question 6

is the horse ascarid.

Answer 6

Parascaris equorum

Question 7

is the horse ascarid.

Answer 7

Parascaris equorum

Question 8

is the horse ascarid.

Answer 8

Parascaris equorum

Question 9

Horses, like people and unlike dogs, can have pinworms. Two kinds of pinworms occur in horses.
A rather large one, the females of which can be up to 63 millimeters long, is_________________The minute
horse pinworm, ____________ is only about 2 millimeters long and is of little consequence.

Answer 9

Oxyuris equi.

Probstmayria sp.

Question 10

is a protozoan disease occurring in horses, mules,
and donkeys.

Answer 10

Equine piroplasmosis, or equine babesiosis,

Question 11

Two species of Babesia

Answer 11

B. caballi and B. equi

Question 12

The tropical horse tick

Answer 12

(Dermacentor nitens) serves as intermediate host

Question 13

The brown dog tick__________ may be able to serve as an intermediate host for B. equi..

Answer 13

_(Rhipicephulus sanguineus)

Question 14

probably occurs throughout North America, affecting male and female horses equally.
Thoroughbreds and Standardbreds are affected more frequently. Signs can appear at any age, but most
cases occur in horses under 4 years old.

Answer 14

Equine Protozoal Myeloencephalitis (EPM)

Question 15

probably occurs throughout North America, affecting male and female horses equally.
Thoroughbreds and Standardbreds are affected more frequently. Signs can appear at any age, but most
cases occur in horses under 4 years old.

Answer 15

Equine Protozoal Myeloencephalitis (EPM)

Question 16

Most likely the protozoan ___________________ causes
EPM

Answer 16

Sarcocystis neurona

Question 17

Most likely the protozoan ___________________ causes
EPM

Answer 17

Sarcocystis neurona

Question 18

species are nematodes that occur as adults in connective tissue of horses, mules, and
donkeys. They are fairly common parasites.

Answer 18

Onchocerca species

Question 19

, is about 19 millimeters long and lives in the tear duct
and conjunctival sac of the horse’s eye.

Answer 19

Thelazia lacrymalis

Question 20

develops in the eye and causes damage.
Normally, these nematode parasites, which use mosquitoes as intermediate hosts, occursin the abdominal
cavity and are of little or no consequence.

Answer 20

Setaria equina

Question 21

External parasites of horses include

Answer 21

ticks, mites, chiggers, and lice

Question 22

The winter tick,_____________has become widely distributed because horses now are
commonly transported from one part of the country to another. Although this tick occurs primarily on
the horse, it is found on other farm animals, such as cattle, sheep, and goats, so these animals can also be
involved in its spread.

Answer 22

Dermacentor albipictus

Question 23

The Pacific coast tick,____________________ is found chiefly
in coastal areas of the West. Unlike the winter tick, this tick drops off the
host to lay its eggs, and the larvae and nymphs feed on small mammals
before becoming adults and parasitizing horses.

Answer 23

Dennacentor occidentalis

Question 24

The ear tick, _________________like Dermacentor albipictus, is a one-host tick. It is common on
horses but is also found in the ears of cattle, sheep, dogs, cats, and, occasionally, people. These ticks,
however, do not occur on the horse in their adult stage: only the larvae and nymphs are found in the
horse’s ears. Adults have nonfunctional mouth parts but may survive for 2 years on the ground.

Answer 24

Otobius megnini

Question 25

are ectoparasites that are closely related to ticks and cause a skin condition called mange.
The entire life cycle of mange mites occurs on the horse. Mating occurs on the skin or in burrows the
mites make in the skin. The eggs hatch on the host after about 4 days and are mature, egg-laying adults
12 to 15 days later.

Answer 25

Mites

Question 26

causes lesions usually found on the
neck, shoulders, head, chest, and flanks of horses. These mites burrow
under the skin and cause severe irritation and itching.

Answer 26

Sarcoptic mange (Sarcoptes)

Question 27

produces lesions like sarcoptic
mange, but since the mites occur more commonly on the lower
extremities, it often is called foot mange.

Answer 27

Chorioptic mange (Chorioptes)

Question 28

occurs primarily on the poll or the tail. This mange mite (Psoroptes) also causes
intense itching, with hair loss and scabs if the horse traumatizes itself extensively.
Mange mites can live off the host for a short time and can be transferred from one host to another
on combs, blankets, and so forth. In the past, mange has been extremely difficult to control; but with the
new ivermectins, mange should become a less-se1ious problem.

Answer 28

Psoroptic mange

Question 29

occurs primarily on the poll or the tail. This mange mite (Psoroptes) also causes
intense itching, with hair loss and scabs if the horse traumatizes itself extensively.
Mange mites can live off the host for a short time and can be transferred from one host to another
on combs, blankets, and so forth. In the past, mange has been extremely difficult to control; but with the
new ivermectins, mange should become a less-se1ious problem.

Answer 29

Psoroptic mange

Question 30

_________affect horses in much the same way they affect people. _________
are the larval stage of harvest mites (Trombicula) that affect horses’ feet and
muzzles as they walk and feed on infested pastures.

Answer 30

Chiggers

Question 31

Lice can be a very serious problem in horses. There are two kinds of lice:

Answer 31

biting lice (Damalinia), which feed on skin and hair, and sucking lice
(Haematopinus), which pierce the skin and suck blood and tissue fluids

Question 32

very often cause
intense itching and attendant lesions in horses’ ears, although they will bite other thin-skinned areas of
the horse as well.

Answer 32

Black flies and “no-see-ums”

Question 33

are fly larvae that are parasites in the stomach of horses.

Answer 33

Bot

Question 34

are the two common botflies found in this country.

Answer 34

Gastrophilus intestinalis, the
common horse bot, and
G. nasalis, the throat botfly