Equine- Large Strongyles, Small Strongyles and Filarioidea

Question 1

What is Dictyocaulus arnfieldi Hosts?

Answer 1

Donkeys

In horses adults do not reach sexual maturity and patency

Question 2

What is Dictyocaulus arnfieldi Identification?

Answer 2

Slender nematodes in bronchi 8 cm long

Question 3

What is Dictyocaulus arnfieldi Site(s) of infection?

Answer 3

Lungs

Question 4

What is Dictyocaulus arnfieldi Life cycle?

Answer 4

Adult stages in bronchi lay eggs containing L1
Eggs hatch in lungs and in feces; eggs and L1 found in feces
Develop to L3, migrate from feces to herbage where ingested

Question 5

What is Dictyocaulus arnfieldi Pathogenesis and lesions?

Answer 5

Horses: damage to pulmonary tissue

Question 6

What is Dictyocaulus arnfieldi Clinical signs?

Answer 6

No clinical signs in donkeys

Horses: chronic, productive cough

Question 7

What is Dictyocaulus arnfieldi Diagnosis?

Answer 7

L1 recovered in fresh feces and lung washings

Adults in lungs at necropsy

Question 8

What is Dictyocaulus arnfieldi Treatment and prevention?

Answer 8

In endemic areas do not pasture horses and donkeys together

Question 9

What is Subfamily Strongylinae Common name?

Answer 9

large strongyles

Question 10

What is Subfamily Strongylinae Examples?

Answer 10

Strongylus vulgaris
Strongylus edentatus
Strongylus equinus

Question 11

What is Subfamily Cyathostominae Common name?

Answer 11

small strongyles

cyathostomins

Question 12

Large Strongyles were the main problem causing parasite.
•MCLs and other anthelmintics effectively controlled them.
•Now Small Strongyles (cyathostomins) are the main problem causing parasite.

Answer 12

.

Question 13

Large Strongyles
•3 species to be discussed
•Larvae migrate in organs; colic
•Adults bloodsuckers/plugfeeders; anemia Cyathostomins
•>50 species
•Larvae damage large intestine mucosa = colic; diarrhea
•Resistance

Answer 13

.

Question 14

What is Large Strongyles Identification?

Answer 14

Adult mouth capsule
All eggs the same
L3 can be distinguished

Question 15

What is Large Strongyles Site of infection?

Answer 15

Adults large intestine

L3/L4 location species dependent

Question 16

What is Strongylus vulgaris Identification?

Answer 16

Adult 1-2 cm

Question 17

What is Strongylus vulgaris Life Cycle?

Answer 17

PPP 6 mo
Larvae migrate in arterial vessels of intestine
Larval stages in cranial mesenteric, ileocolic arteries and other arteries to intestine

Question 18

What is Strongylus vulgaris Pathogenesis and lesions?

Answer 18

Larvae cause arteritis, marked thickening, thrombus, infarction, death
Aberrant larvae migration
Adults are bloodsuckers; remove plugs of mucosa

Question 19

What is Strongylus vulgaris Clinical signs?

Answer 19

Larvae: thrombo-embolus; colic
Adults: anemia in heavy infections

Question 20

What is Strongylus edentatus Identification?

Answer 20

Adults 3-4 cm

Question 21

What is Strongylus edentatus Life Cycle?

Answer 21

PPP 11 mo
Larval stages in liver and abdominal
tissues (flanks)

Question 22

What is Strongylus edentatus Clinical Signs/Diagnosis?

Answer 22

Acute (larvae): fever, anorexia
Chronic (larvae): intermittent colic
Adults: anemia in heavy infections

Question 23

What is Strongylus equinus Identification?

Answer 23

Adults 3-4 cm

Question 24

What is Strongylus equinus Life Cycle?

Answer 24

9 mo

Question 25

What is Strongylus equinus Site of Infection

Answer 25

Larvae in liver

Question 26

What is Strongylus equinus Clinical Signs/Diagnosis?

Answer 26

Larvae form hemorrhagic tracts | Adults: anemia in heavy infections

Question 27

What is Large Strongyles Clinical signs?

Answer 27

Colic most typical Fever, anorexia, constipation, etc. Adults, in heavy infections, anemia

Question 28

What is Large Strongyles Diagnosis?

Answer 28

Eggs in fecal exam and identification of L3 Can not differentiate the eggs of the cyathostomins from the large strongyles Ultrasound, arteriography, etc for migrating larvae Necropsy

Question 29

What is Cyathostomins Identification?

Answer 29

Adults normally < 1.5 cm Mouth capsule rectangular or square Egg typical strongyle Over 51 species

Question 30

What is Cyathostomins Life cycle?

Answer 30

``` PPP: 6 wk to 2-4 mo Arrested development (up 2 ½ y) ```

Question 31

What is Cyathostomins Site(s) of infection?

Answer 31

Larvae throughout large intestine mucosa | Adults in intestinal lumen (large intestine)

Question 32

What is Cyathostomins Pathogenesis and lesions?

Answer 32

Larval cyathostominosis Lymphocytic and eosinophilic infiltration Catarrhal colitis Protein losing enteropathy

Question 33

What is Cyathostomins Clinical signs?

Answer 33

``` Primarily clinical signs associated with emergence of L4 Primarily young animals, older possible Chronic diarrhea; colic Seasonality Severe weight loss, edema ```

Question 34

What is Cyathostomins Diagnosis?

Answer 34

Eggs in fecal examination (McMaster) Distinguish cyathstomin L3 from large strongyle L3 Eggs in feces of foals (< 6 wk) due to coprophagia

Question 35

What is Cyathostomins Epidemiology: Northern temperate climate?

Answer 35

Larvae arrest during winter Emerge, adults spring Egg counts increase in spring

Question 36

What is Cyathostomins Epidemiology: Southern temperate climates?

Answer 36

Larvae encysts during summer | Transmission occurs during winter

Question 37

What is Cyathostomins Epidemiology: | History of horses with syndrome?

Answer 37

Inadequate trtmt during the preceding grazing season Over-stocked, highly infective pastures These circumstances result in accumulation of late large burdens of encysted larvae

Question 38

What is Cyathostomins Epidemiology:

Answer 38

Mare origin of infection | Each horse has own supply of mucosal larvae to become next season’s adults

Question 39

What is Cyathostomins Treatment?

Answer 39

Some BZs and MCLs for mucosal larval stages BZs, MCLs and others for adults Resistance to all drug classes

Question 40

What is Cyathostomins Resistance?

Answer 40

Survive treatment with an antiparasitic drug that is generally effective against the same parasite species at the same dose and against the same stage of infection. Tolerate the approved dose of an antiparasitic drug to which they were previously susceptible due to genetic mutations.

Question 41

What is Cyathostomins Prevention/management?

Answer 41

``` Accurate diagnosis required Culture eggs; identify L3 Manage pasture Treat animals contaminating the pasture Clean up feces Mixed grazing Do not overstock ```

Question 42

What is Superfamily Filarioidea Characteristics?

Answer 42

Indirect life cycle; all depend on insect vectors Females lay eggs or larvae (mff) which develop to L3 Mff taken up by parasitic insects feeding on blood and tissue fluids Mff circulate in blood of definitive host (e.g. Setaria, Dirofilaria, Acanthocheilonema) Mff accumulate in dermal connective tissues (e.g. Onchocerca)

Question 43

What is Setaria equina Identification?

Answer 43

.Long slender worms 12 cm

Question 44

What is Setaria equina Life cycle?

Answer 44

Mff in blood; Mff to L3 in Mosquito; L3 infective; L3 migrates, 2 molts to adult

Question 45

What is Setaria equina Site(s) of infection?

Answer 45

Adults in peritoneal cavity Microfilariae in blood Nematodes are not pathogenic Noted during abdominal surgery or at necropsy

Question 46

What is Onchocerca cervicalis Identification?

Answer 46

lender nematodes up to 6

Question 47

What is Onchocerca cervicalis Life cycle?

Answer 47

Mff in tissue spaces of skin; Mff to L3 in Culicoides spp; L3 infective; L3 migrates, 2 molts to adult

Question 48

What is Onchocerca cervicalis Site(s) of infection?

Answer 48

Adults coiled in tissue nodules in deep connective tissue (ligamentum nuchae)

Question 49

What is Onchocerca cervicalis Other?

Answer 49

Fibrous tissue; dermatitis; purulent lesions?