NEMATODES: Rhabditoidea spp.

Question 1

Which of the following characteristics is not associated with the Superfamily Rhabditoidea?
A) Direct life cycles, but a potential for paratenic hosts
B) Infectious L3 larval stages
C) Reduced in length and size
D) Free-living
E) Two of the above
F) None of the above

Answer 1

F) None of the above

Question 2

What causes the conversion of non=parasitic rhabditoid larvae to become infectious?

Answer 2

Harsh environmental conditions, or other hazardous factors

Question 3

In genus Strongyloides, describe the parasites.

Answer 3

Adults are small, only adult females are found in the small intestine of the host, have long filariform esophagus

Question 4

Describe the homogenic life cycle of Strongyloides spp.

Answer 4

Parthenogenic
1 adult = 1 offspring
- Parasitic female in SI, ova hatches in SI.
- L1 shed in feces (stercoralis) or ova shed in feces (other)
- L1-L2 free-living/ L3 infective transmission by skin/oral mucosa penetration, tissue migration to trachea/lungs (some somatic migration)
- Cough up L3 and reingest, maturation to parasitic female in SI

Question 5

Describe the heterogenic life cycle of Strongyloides spp.

Answer 5

Sexual reproduction increases the number of offspring

• Parasitic female in SI, ova hatches in SI
• L1 shed in feces (stercoralis) or ova shed in feces (other)
• L1-L4 free-living adult or L1-L2 free-living/L3 infective penetrate skin/oral mucosa, leading to tissue migration to trachea/lungs (plus some somatic migration)
• L3’s are coughed up and re-ingested. with maturation to parasitic female in SI

Question 6

What methods of transmission are associated with Strongyloides spp.

Answer 6

PO, percutaneous, transmammary, prenatal/ transplacental

Question 7

What common name is associated with Strongyloides spp.?

Answer 7

Threadworm

Question 8

What diagnostic test would be associated with Strongyloides spp. infections?

Answer 8

Baerman for L1 larvae (only S. stercoralis) or Fecal flotation for L1 larvae (S. papilosus, S. ransomi, S. westeri)

Question 9

What stage is infectious for Strongyloides spp.?

Answer 9

L3

Question 10

Where will L3 larvae migrate to in infected species?

Answer 10

The lungs

Question 11

What is the PPP of the Strongyloides spp.

Answer 11

8 - 14 days ( 1 - 2 weeks)

Question 12

What clinical signs are associated with Strongyloides spp. infections?

Answer 12

Enteritis, diarrhea, anorexia and weight loss; erythematous reaction and urticaria (skin infection as a direct result from strongyloides spp migrations)

Question 13

What is the primary mode of infection associated with strongyloides spp.?

Answer 13

Transmammary

Question 14

While immunity development is associated with Strongyloides spp. infections, what age of animals is more severely afflicted?

Answer 14

Younger

Question 15

Who are the DH’s for Strongyloides stercoralis?

Answer 15

Dogs and cats

Question 16

What Strongyloides spp. are zoonotic?

Answer 16

Strongyloides stercoralis

Question 17

Who are the DH’s for Strongyloides westeri?

Answer 17

Equids

Question 18

True or False: Control is only achieved during treatments for other parasites, as S. westeri is unlikely to be treated for specifically on its own.

Answer 18

True, adult equids over 5 months of age develop strong immunity to S. westeri

Question 19

Who are the DH’s for Strongyloides papillosus?

Answer 19

Large and small ruminants

Question 20

Who are the DH’s for Strongyloides ransomi?

Answer 20

Swine

Question 21

While infection results in strong immunity for adults, neonatal pigs and piglets are highly susceptible to dying due to a reduced PPP. What is the least amount of days that it takes for egg production by adults to occur for S. ransomi?

Answer 21

2 days

Question 22

Define parthenogenetic reproduction.

Answer 22

A form of reproduction in which an egg can develop into an embryo without being fertilized by a sperm