Nematodes VI: Strongyloides

Question 1

What do the Strongyloides free living stages (L1 and L2) have?

Answer 1

Rhabditiform esophagus

Question 2

What makes up the rhabditiform esophagus?

Answer 2

Bulb
Isthmus
Corpus

Question 3

Describe the heterogonic life cycle

Answer 3

Free living life cycle
L1 in eggs passed in feces
L1 and L2 in feces
Filariform larvae (L3) in contaminated soil
Free-living male and female adults

Question 4

Describe the homogonic life cycle

Answer 4

Filariform larvae (L3) are in contaminated soil and penetrate skin
—Infective L3 larvae
Parthogenesis
—parasitic females only (parasitic males do not exist)
—Clones of eggs

Question 5

What is the percutaneous transmission route?

Answer 5

L3s penetrate skin –> circulatory –> lymphatic systems –> lungs –> alveoli –> migrate or coughed up and swallowed –> mature in SI

Question 6

What is the peroral transmission route?

Answer 6

Penetrate oral mucosa and migrate as they do in percutaneous OR
Ingest infective L3; go directly to SI

Question 7

What is the host of ransomi?

Answer 7

Swine

Question 8

What is the route of infection for ransomi? What is the PPP for each?

Answer 8

Percutaneous* (7-10)
Peroral (7-10)
Transmammary** (4)
Transplacental (4)

Question 9

Describe the percutaneous or peroral Strongyloides ransomi transmission route

Answer 9

Filariform larvae

Tracheal migration to maturation

Question 10

Describe somatic migration of Strongyloides ransomi

Answer 10

Accumulate as arrested larvae

—Adipose tissues, especially mammary tissues

Question 11

Where do mature gilts store Strongyloides ransomi larvae?

Answer 11

Adipose tissues

Question 12

Where do mature gilts shed Strongyloides ransomi larvae?

Answer 12

Colostrum and milk

Question 13

What is the key to epidemiology in swine with Strogyloides ransomi?

Answer 13

Transmammary

Question 14

What is necessary to diminish larval development as well as multiplication of free-living generations of Strongyloide ransomi?

Answer 14

A high level of hygiene

Question 15

What is the host of Strongyloides westeri?

Answer 15

Equids

Question 16

What is the route of infection for Strongyloides weteri? What is the PPP of each?

Answer 16

Percutaneous (7-10)
Peroral (7-10)
Transmammary** (4)

Question 17

What is the most important route of transmission for Strongyloides westeri?

Answer 17

Transmammary

Question 18

When do foals shed Strongyloides westeri eggs?

Answer 18

10 to 14 days after birth

Question 19

What are clinical signs of Strongyloides westeri?

Answer 19

Diarrhea (foal-heat)

Question 20

What is the zoonotic potential of Strongyloides westeri?

Answer 20

Creeping eruption

—Allergic response to free-living L3 in humans

Question 21

What is the host of Strogyloides papillosus?

Answer 21

Ruminants

Question 22

What is the route of infection for Strongyloides papillosus? What is the PPP for each?

Answer 22

Percutaneous: primary route for sheep/goats (7-10)
Transmammary: primary route for cattle (6)

Question 23

What is the technique of choice for diagnosing Strongyloides ransomi, westeri, and papillosus?

Answer 23

Fecal flotation

Question 24

What are the adults of Strongyloides ransomi, westeri, and papillosus like?

Answer 24

Small (3-10 mm)
Embedded in SI mucosa
Generally need skin scraping of mucosa

Question 25

How can you control Strongyloides ransomi, westeri, and papillosus?

Answer 25

Maintain clean, dry envrionment

Question 26

What is the host of Strongyloides stercoralis?

Answer 26

Canids

Question 27

What is the route of infection for Strongyloide stercoralis? What is the PPP?

Answer 27

Percutaneous (7-10)

Question 28

Describe autoinfection with Strongyloides stercoralis

Answer 28

Rare Tends to happen only if bitch is infected while lactating Hyperinfection, or uncontrolled autoinfection is also rare

Question 29

What are the different Strongyloides stercoralis third stage larvae?

Answer 29

Auto-infective third stage larvae (L3a) | Infective third stage larvae (L3i)

Question 30

Describe L3a

Answer 30

Develop within intestine of dog | Invade dog through wall of large intestine

Question 31

Describe L3i

Answer 31

Develop in environment | Invade dog through skin

Question 32

How can you diagnose Strongyloide stercoralis?

Answer 32

L3a in lung of host Blood filling alveolar space L1 in feces of infected host Technique of choice: Baermann

Question 33

How can you diagnose Strongyloides sterocoralis adults?

Answer 33

``` Mucosal scraping Parasitic female (long esophagus) ```

Question 34

What king of problem does strongyloides stercoralis tend to be?

Answer 34

Kennel problem | ---Summer with hot/humid weather

Question 35

What is the zoonotic potential of Stronglyoides stercoralis?

Answer 35

Cutaneous larva migrans

Question 36

How can you control Strongyloides stercoralis?

Answer 36

Maintain clean, dry environment

Question 37

What is the host of Strongyloides tumefaciens?

Answer 37

Felids

Question 38

What is the route of infections for Strongyloides tumefaciens?

Answer 38

Percutaneous and Peroral | Life cycle is unknown

Question 39

What is the clinical sign for Strongyloides tumefaciens?

Answer 39

Grossly visible tumor-like nodules in large intestine