Parasites

Question 1

Gasterophilus intestinalis

Answer 1

Horse GI

-Bot fly larvae; stomach bot

-Yellowish eggs on medial aspect forelimb cannon b

CS: usually none, +/- gastritis or stomach rupture

Tx: ivermectin in early summer and fall

Question 2

Oxycuris equi

Answer 2

Equine GI pinworm

CS: anal pruritus, tail rubbing, alopecia in perianal region

• F worms crawl out of anus and cement eggs to perineal region, larvae hatch –> discomfort

Dx: scotch tape prep

Question 3

Parascaris equorum

Answer 3

Eq roundworm (ascarid) (GI)

CS: respiratory signs (bc migrate thru lungs, predisposes to infection), weight loss, D, colic (intestinal impaction) in foals, immune mediated HS in adults

tx - anthelmintic - kill off slow - will cause massive die off and impaction

• likely cause if horse has colic and recently dewormed

Question 4

strongylus vulgaris

Answer 4

Equine GI parasite

Thrombosis or arteritis of cranial mesenteric artery

-Migration to cranial mesenteric aa and corresponding immune response can result in thrombosis of cranial mesenteric a and leads to colic (cut off blood supply) and bowel infarct

Question 5

Strongylus edentatus and Strongylus equinus

Answer 5

Eq GI parasites

Migrate thru portal vein and into liver, through peritoneum and retroperitoneal space, then after a few mo return to gut - could be found in liver, pancreas, perirenal

tx - ivermectin, fenbendazole, oxibendazole

Question 6

strongyloides westerni

Answer 6

Eq GI parasite

CS - D in foals - transmit parasite in milk, env contamination

tx - ivermectin or oxibendazole - give ivermectin to preggo mare to prevent dz in foal

Question 7

anoplocephala magna, A. perfliata, paranoplocephala mamillana

Answer 7

Eq GI tapeworm

CS - GI disturbances and ulceration, unthriftiness, anemia, colic - esp young

• Hits ileocecal junction

Tx - praziquantel, pyrantel effective against anoplocephala

Question 8

Trichostrongylus axei

Answer 8

Equine small stomach worm (hairworm)

CS: chronic gastritis, weight loss - penetrate mucosa causing ulceration and thickening. can also affect ruminants, see in horses housed near cattle

Tx - benzimidazole, ivermectin

Question 9

Ascaris suum

Answer 9

Porcine roundworm

Migrates through liver – causing milk spots, migrates through lungs – causing thumps (cough) Animal may sporadically die d/t intestinal impaction, but usually not very many clinical signs

Necropsy = “milk spots” in liver (condemnation of meat), 20-40cm worms in intestines

tx - fenbendazole

Question 10

Haematopinus suis

Answer 10

swine lice

indicates poor management

• can transmit swine pox

CS: pruritus, anemia, poor growing

Dx - visible

Tx - avermectin, same as mange

Question 11

isospora suis

Answer 11

swine coccidiosis

D+ in nursing & weaning pigs – HIGH morbidity – usually affects confined 1-3 week old pigs o Watery D+, ill thrift, failure to gain weight, dehydration – other DDx for this age & signs = E. coli o To differentiate – coccidia will not respond to antibiotics!

tx - amprolium, IMPROVE sanitation

Question 12

metastrongylus

Answer 12

swine lungworm

Transmission: earthworms are intermediate host = prevent access to soil that contains earthworms.

CS - coughing, unthriftiness, may acquire secondary pneumonia

Question 13

Sarcoptes scabei var suis

Answer 13

ZOONOTIC
- young nursery or growers
-CS: intense pruritus, thickened skin, poorp production, susceptible to other dz. Adults burrow top layers of skin - ears, face, neck, shoulders

Dx: CS + skin scape behind ears/ear canal

Tx - avermectin

Question 14

Stephanarus dentatus

Answer 14

Swine Kidney worm
Transmission: earthworm intermediate host, prevent access to soil w/ worms
CS: unthriftiness, slow growth, death - posterior ataxia/paralysis dt migrating larvae at SC
Dx - UA, on nx find worms in kidneys, ureters, perirenal fat

Question 15

Strongyloides randomi

Answer 15

Swine threadworm
Transmission: transcolostrally - worms reside in SI of suckling piglets
CS - heavy infestations see D, anemia, emaciation, death
Tx - ivermectin, benzimidazole

Question 16

Trichinella spiralis

Answer 16

Swine
Can affect most mammals
Transmission: ingest encysted larvae in muscle, inf in pigs d/t eating garbage
Prevent pigs from getting it by cooking their food, prevent cannibalism
ZOONOTIC - eating undercooked pork

Question 17

Taenia solium

Answer 17

Swine tapeworm
ZOONOTIC - cysticercosis when eating undercooked pork
Pigs act as intermediate host by eating infected human feces - cysticerci then form in pigs cardiac/skeletal mm - humans eat meat that contain cysts and adult tapeworms

Question 18

trichuris suis

Answer 18

Swine whipworm
Mucohemorrhagic D (large bowel) - affects all ages, usually weaned pigs
Dx - double operculated egg on fecal float, nx find eggs in cecum and colon
Px - give anthelmintic a week before farrowing, move to clean pasture

Question 19

Eimeria

Answer 19

Coccidiosis in ruminants (isospora in carnivores)
Calf dz - nervous coccidiosis in cattle <1y (>21d), see D (bloody, tenesmus) followed by neuro signs
tx w/amprolium (monensin, sulfa-drugs)

Question 20

Haemonchus contortus

Answer 20

Anemia and hypoproteinemia (NOT D) in sheep/goats, blood sucker of abomasum
CS: chronic weight loss, doing poorly, no D, pale mm
tx w fenbendazole

Question 21

Monezia

Answer 21

Ruminant tapeworm
Rectangular (or triangular), usually non-pathogenic, can cause intestinal stasis
Intermed host - masture mite

Question 22

Nematodirus

Answer 22

Ruminants
CS: young animals w/profuse watery D, anorexia, weight loss, dehydration
Coincides with coccidiosis season in spring
Elliptical appearance w/sharply curved poles & 2-8 blastomeres surrounded by fluid filled cavity

Question 23

Ostertagia ostertagii

Answer 23

Ruminant roundworm
Type 1:
-Acute weight loss (anorexia/poor growth) and D (naive cows)
-D in <2y on pasture - chronic dz
-occurs summer/fall - infection w/L3, egg counts high, not associated with large numbers of larvae with few adults in abomasum

type 2:
- chronic weight loss, D - older cows
- occurs in spring - low egg counts
-Lots of inhibited L4 that rapidly emerge and see thousands of larvae in abomasum (Moroccan leather)

tx - ivermectin (all life stages) or fenbendazole

Question 24

strongyloides spp

Answer 24

Intestinal threadworm (ruminant)
Migrate through oral mucosa or skin, enter bloodstream, head for heart, travel thru lungs/trachea where coughed/swallowed and enter GI

Question 25

Trichuris ovis, T. discolor

Answer 25

sheep and cattle whipworm, same as other whipworm spp

Question 26

Chorioptes equi

Answer 26

Equine mange mite
Lesions near foot and fetlock (esp drafts) - pruritic dermatitis
Ivermectin

Question 27

Culicoides hypersensitivity (Sweet itch)

Answer 27

Saliva of gnat causes type I HS - very pruritic diffuse lesions
Vector for bluetongue and Onchocerca
Common in warm months - seasonal
Worsens with age
tx - dec exposure, steroids

Question 28

demodectic mange

Answer 28

Rare in horses - not pruritic, see on head, neck, withers - only form of mange

Question 29

Habronema muscae

Answer 29

Equine stomach worm aka summer sores
-Larvae of worm migrate and emerge, creating granulomatous lesions (eyes, genitalia, lower extremities) - inside lesions will find calcified larvae
- Gastritis, eosinophilic granuloma (summer sore)
Vector: Stomoxys calcitrans (houseflyy)

Question 30

Haematobia irritans

Answer 30

Horn/face fly of cattle
Bigger problem in cattle (repro in cattle feces), but affects horses (when housed near cattle)
CS: Ventral midline dermatitis, focal lesions w/wheals and crusts on ventral midline that is NON-pruritic

Question 31

Hypoderma lineatum, H bovis

Answer 31

Cattle grub, heel fly, warble fly
F attaches eggs to hairs on feet, L1 hatch and burrow into skin
- H. bovis migrates to epidural fat in SC
- H lineatum migrates to esophagus
They become L2 –> migrate to SQ tissue in back –> become L3 –> nodules on dorsum w/pore on top (breathing hole)

tx - ivermectin early fall, emerge from back in spring but crucial to tx in fall

Huge economic loss dt hide damage

Question 32

melophagus ovinus

Answer 32

Sheep ked
Have 6 legs - wingless flies and adults feed on blood
CS: pruritus, stained wool, potentially anemia

Question 33

Onchocerca cercivalis

Answer 33

Vector - culicoides
CS: dermatitis dt HSE of dying microfilariaa, rare in horses <2y
Diamond shaped lesions (Bulls eye lesion) on head, ocular lesions (uveitis, conjunctivitis, keratitis) dt aberrant migration of MF, ventral midline dermatitis
Non-seasonal and non-pruritic
tx - ivermectin for microfilaria, none for adults

Question 34

sarcoptes scabei

Answer 34

sarcoptic mange
Most economically important in swine - severely pruritic, hyperkeratotic ear lesions
-head/neck/ears in horses
CS: Dec growth, dec milk production, hide damage
ZOONOTIC and REPORTABLE - skin lesions in humans
Ivermectin

Question 35

Thazia lacrymalis

Answer 35

Eye worm
Vector: Musca autumnalis (face fly of horse)
tx - remove manually and add 10% levamisole drops

Question 36

fasciola hepatica & F magna

Answer 36

aquatic snails + vegetation = IH
young - liver parenchyma, adults - bile duct
CS: acute hepatitis/death (weakness, anemia, bottle jaw); chronic bile duct stenosis
Dx - nx, sediment, CS
tx w cloruson (seasonality - spring and fall)

Question 37

Hematopinus

Answer 37

Blood sucking lice on cows
CS - severe anemia in calves 2-7m - become susceptible to pneumonia
dx skin scrape - lice have 6 legs

Question 37

Dictyocaulus arnfeldi

Answer 37

Horse lungworm
Definitive host: donkey - see in horses near donkeys
dx - Baermann (detect L1 that hatch in feces), transtracheal wash

Question 37

Dictyocaulus filarial

Answer 37

goat lungworm
Bronchitis in goats

Question 37

Dictyocaulus viviparous

Answer 37

Horse lungworm
Ingest L3 - hatch in SI, migrate via lymphatics to lungs, molt to L4, grow to adults, cough and swallow eggs, molt in intestine, molt on ground after being defecated
dx - tracheal wash, Baermann
Fenbendazole, ivermectin, levamisole, albendazole

Question 38

Neospora caninum

Answer 38

ABORTION (4-6m) in cattle - may see dog on farm that is suffering from diffuse mm atrophy, trouble ambulating in hind limb (dogs have neuro/mm abn)
-Dog is definitive host
-Most other abortions occur later in gestation (Brucella, listeria, lepto)
-Usually see autolysis of fetus w/granulomas in brain

Question 39

oestrus ovis

Answer 39

Sheep
Fly deposits larvae at nostrils and they migrate into nose where they develop
CS - sneeze, head shaking, nose rubbing, nasal DC, stridor (heavy inf - HSE Response)
dx - cytology of nasal DC - eos and mast cells
tx w/ivermectin

Question 40

sarcocystis

Answer 40

S. hirsuta (cat), S hominis (human), s cruzi (dog) - all affect cattle as intermediate host
carnivore eats cow w/cyst in mm –> cyst forms sporocysts, shed in feces, eaten by cow, sporocysts hatch and eventually invade mm (10w)
cows CS: fever, anorexia, salivation, weakness, mm fasciculations, weight loss, sporadic abortions
px - prevent carnivore feces

Question 41

cochliomyia homonivorax

Answer 41

Screwworm
eradicated from US (reportable)
Released from sterile males, may see metallic blue/green fly leaving wound
CS: myiasis, eggs on wounds, maggots feed on flesh that create large wound

Question 42

Trypanosoma cruzi

Answer 42

Reduvid beetle, vector for Chagas dz (zoonotic)
CS - general febrile dz. chronic - cardiac dz, NS, GI
Present in South America and some parts Africa

Question 43

SA coccidia

Answer 43

Eimeria: 4 sporocysts, from eating rabbit feces - parasite in birds/reptiles/herbivores - no tx

Isospora tx/sulfadimethoxine (Albon)

Cryptosporidium - round and slightly smaller than RBC, acid-fast or IFA stain, resistant to disinfections. Tx - clindamycin, azithromycin, tylosin

Question 44

Ancylostoma

Answer 44

Dog hookworm
dx - fecal float
Puppies/kittens most affected
ZOONOTIC - cutaneous larval migrans
A. caninum (dogs): GI signs, anemia, lethargy, melena, weight loss, chill in SI. Transmammary and transplacental transmission, eating poo, L3 penetrates skin

A. tubaeforme (cats): Same CS - no transmammary/transplacental, only eating poo/L3 penetration

A braziliense in dogs/cats

tx - not praziquantel (pretty much everything else)

Question 45

Toxocara

Answer 45

Dog roundworm
dx - fecal float, larvae: liver –> lungs –> up MCE, cough –> swallow –> develop in SI
ZOONOTIC: visceral and ocular larval migrans

T. canis (dogs): can be asymptomatic, GI signs, more severe in puppies/kittens - no weight gain, unthrifty, pot bellied, coughing (transplacental/transuterine transmission most common, eating poo, transmammary)

T. cati - cats, same CS (transmammary, eating poo)

T leonina - dogs and cats, no migration out of GIT; transmission only eating poo

Tx with fenbendazole, milbemycin, pyrantel

Question 46

Anticestodal (tapeworms)

Answer 46

Praziquantel
- Droncit (Praziquantel) - dogs/cats
- Drontal (Praziquantel + Pyrantel) - dogs/cats, tapes/hooks/rounds
- Drontal + (Praziquantel + pyrantel + febantel) = dogs, tapes/hooks/rounds/whips/giardia
- intercepter plus (Praziquantel + milbemycin oxime) - dogs, tapes/hooks/rounds/whips/demodex/HWP
-Profender (Praziquantel + emoodepside) - cats, tapes/hooks/rounds