Parasitology - Nematodes 5

Question 1

What are the two superfamilies of Spirurida?

Answer 1

Filaroidea
Non-filaroidea

Question 2

While spirurida is a diverse order and quite difficult to find general characteristics, what do all members have?

Answer 2

an arthropod as an intermediate host

Question 3

What do spuririda parasitize?

Answer 3

variety of tissues in vertebrate host

Question 4

Explain the morphology and location of filaroidea

Answer 4

not in GI tract - usually pulmonary arteries
long slender worms

Question 5

What is the direct host and intermediate host of Spirurida?

Answer 5

arthropods - (mosquitoes are intermediate hosts)
dogs are definitive

Question 6

What do Spirurida produce?

Answer 6

ovoviviparous - Microfilariae - pre-L1 stage

Question 7

Explain the lifecycle of heartworm

Answer 7

Mosquito feeds and ingests microfilariae with blood
mosquito matures in infective L3 2 weeks post infection
larvae deposits during subsequent bites
L3 matures into L4 in SC tissue in 1-3 days
L4 larvae migrate through tissues and are sexually immature and migrate to heart and lungs
worms develop to maturity in pulmonary artery

Question 8

What are the 3 main disease components of Dirofilaria immitis?

Answer 8

physical obstruction of vessels
inflammation in vessel wall
progressive fibrosis in vessel

Question 9

What disease does Dirofilaria immitis cause?

Answer 9

heartworm

Question 10

The pathogenesis of Dirofilaria immitis can progress and what happens to the heart?

Answer 10

reduced cardiac output and compensatory right heart enlargement and failure

Question 11

How is Dirofilaria immitis diagnosed?

Answer 11

HWT annually
microfilaria blood sample check

Question 12

Explain the role of Wolbachia in Dirofilaria immitis

Answer 12

filarid parasites have a symbiotic relationship with Wolbachia

Question 13

What medication is being used for treatment of heartworm infection?

Answer 13

Doxycycline

Question 14

Explain Dirofilaria immitis in cats

Answer 14

abnormal host
worms are less successful and cats show less clinical signs as the worms die soon after infection
and more likely to migrate to abnormal sites

Question 15

What types of eggs do non-filaroidea superfamilies produce?

Answer 15

clear, elliptical shaped, smooth, thick shell wall containing a coiled larva

Question 16

What are Habronema and Draschia spp?

Answer 16

live in nodules in equine stomach that causes summer sore a persistent cutaneous granuloma

Question 17

What is the intermediate host of Habronema and Draschia spp?

Answer 17

stable and horse fly

Question 18

Most Enoplida in domestic animals produce what types of eggs? What is unique about the larvae?

Answer 18

eggs with 2 polar plugs with infective larvae develop and remain inside egg

Question 19

What is the worm of Trichuris vulpis

Answer 19

whipworm

Question 20

Where are whipworms found?

Answer 20

large intestine of dogs

Question 21

What is the infective stage of Trichuris vulpis?

Answer 21

embryonated egg

Question 22

How are whipworms detected?

Answer 22

bipolar egg detection in feces

Question 23

What is the pre-patent period of Trichuris vulpis?

Answer 23

3 months

Question 24

What clinical disease is seen with whipworms?

Answer 24

diarrhea +/- blood –> anemia

Question 25

What is Trichinella spp? Explain its life cycle and the important human disease associated with it

Answer 25

adult worms in small intestine of warm blood animals larvae is produced, penetrates gut, and encysts in tissues ingestion of pork leads to trichinosis in humans

Question 26

Where are pinworms found?

Answer 26

small adults in large intestine

Question 27

What species is pinworms found in?

Answer 27

horses, rodents, ruminants, reptiles, people

Question 28

What is the life cycle of pinworms?

Answer 28

direct

Question 29

What do the eggs of pinworms look like?

Answer 29

polar plug with flattened appearance on one side

Question 30

How are pinworms detected?

Answer 30

detection of eggs in perianal swabs

Question 31

What is the common equine pinworm?

Answer 31

Oxyuris equi

Question 32

Explain the life cycle of oxyuris equi

Answer 32

infection from ingestion of eggs fertilized females migrate from LI and rectum onto skin and glue eggs to perianal hairs

Question 33

What does oxyuris equi cause clinically?

Answer 33

pruritis

Question 34

T/F: human pinworm is related to animals

Answer 34

FALSE - transmitted person to person

Question 35

Where are Rhabditida found?

Answer 35

free living in soil

Question 36

Rhabditida is species specific. What is the species that infects Ruminants Horses Dogs

Answer 36

Ruminants - Strongyloides papillosus Horse - westeri dog - stercoralis