Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

serpent taming > Rhabditids > Flashcards

Rhabditids Flashcards

1
Q

True or False:

Most rhabditids are free-living nematodes.

A

TRUE

Only a few are facultative parasites.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the characteristic morphological feature of the rhabditids?

A

Rhabditiform esophagus

(rhabditiform = barbell-shaped)

3 regions:

corpus, isthmus, bulb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Identify this structure and the regions pointed to by the arrows.

A

Rhabditiform esophagus

Top arrow: corpus

Middle arrow: isthmus

Bottom arrow: bulb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name a famous free-living rhabditid nematode.

A

Caenorhabditis elegans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where does Rhabditis strongyloides normally live?

A

Free-living in decaying organic matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Can Rhabditis strongyloides complete its life cycle in host skin?

A

NO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

List some risk factors for an animal becoming infected with Rhabditis strongyloides.

A

Wet, dirty bedding

Animal is sick/recumbent (i.e. hanging out close to the ground)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

List some of the signs associated with “rhabditic dermatitis”

A

Alopecia

Serum exudate

Pruritis

Erythema

Pustules

Secondary bacterial infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

This lesion is from an animal that way laying down in moist bedding for a prolonged period.

  • What parasite might you suspect?
  • How can you confirm your diagnosis?
A
  • Rhabditis strongyloides
  • -*Biopsy and histopathology
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

True or False:

The lesions from Rhabditis strongyloides are typically limited to areas contacting the ground.

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

This is Rhabditis strongyloides found on a biopsy. Where does this worm live in the host?

A

Skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

This is an adult Rhabditis (Pelodera) strongyloides. How would you characterize its esophagus?

A

Rhabditiform

*Note: all stages of Rhabditis have a rhabditiform esophagus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In the skin, where do you usually find R. strongyloides larvae?

A

Hair follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How would you treat an infection with R. strongyloides?

A

Ivermectin

Antibiotics for secondary bacterial infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which host is most often infected by Halicephalobus gingivalis?

A

Equines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

True or False:

Humans usually survive Halicephalobus gingivalis infections

A

FALSE

Always fatal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Unlike Rhabditis, Halicephalobus probably can’t penetrate skin all on its own. How does it gain access to the host?

A

Ingestion

Inhalation

Hematogenous spread

(lactogenic transmission?)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where is Halicephalobus gingivalis usually found in the host?

A

CNS

Kidneys

Heart

Maxilla

Nasal cavity

Prepuce

Mammary gland

Bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What kind of host response is elicited by Halicephalobus?

A

Granulomatous inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Adult Halicephalobus gingivalis females are parthenogenetic. You’ve totally been studying and know what this word means.

Define parthogenetic.

A

Parthogenetic - eggs develop without fertilization from a male.

21
Q

Describe the male of Halicephalobus gingivalis.

A

No male has ever been described.

All infecting Halicephalobus are parthenogenetic females.

22
Q

You find these nodules in a kidney. On histopath, you find a worm with a rhabditiform esophagus. What species do you suspect?

A

Halicephalobus gingivalis

23
Q

Describe the reproductive tract of Halicephalobus gingivalis.

A

Dorsoflexed ovaries

Single egg in uterus

24
Q

Describe the treatment for Halicephalobus gingivalis

A

Surgical resection of affected tissue

Anthelmintics

Low success rate

25
Q

What is the common name of Strongyloides spp.?

A

Intestinal or minute thread worm

26
Q

Which sex of Strongyloides spp. is parasitic?

A

Only females

27
Q

Which phase of the life cycle is found inside in freshly-laid Strongyloides spp. eggs?

A

L1

(Except in Strongyloides stercoralis, in which the eggs hatch in the intestine and the L1 is shed in the feces)

28
Q

What is unique about the Strongyloides spp. life cycle?

A

Has both free-living and parasitic generations

29
Q

Describe the esophagus of an adult parasitic Strongyloides female.

A

Filariform esophagus

(note that these worms are still rhabditids, but adult parasitic females do not have a rhabditiform esophagus)

30
Q

What is the term for the parasitic generation of Strongyloides spp.?

A

Homogonic

31
Q

In the homogonic phase of Strongyloides spp., where does the adult live within the host?

(Recall that homogonic is the parasitic generation)

A

Small intestinal mucosa

32
Q

Parthenogenetic Strongyloides spp. in the host lay eggs, which are deposited in the feces. What life phase is contained within the eggs?

A

Rhabditiform L1

33
Q

What happens to the rhabditiform L1 of Strongyloides spp. once it is shed in the feces? (2 options)

A

Develops into an infective filariform L3, which can infect a host and develop into an adult parasitic female

or

Develops into free-living rhabditiform adult males and females

34
Q

What is the term for the free-living generation of Strongyloides spp.?

A

Heterogonic

35
Q

Is the heterogonic generation of Strongyloides sp. sexual or parthenogenetic?

A

Sexual

Rhabditiform males and females reproduce sexually to produce eggs with rhabditiform L1’s.

(Recall that adult parasitic females are parthenogenetic)

36
Q

What are the two sources of infective filariform L3’s in the Strongyloides sp. life cycle?

A

Eggs from parasitic parthogenetic females

Eggs from sexual free-living adults

37
Q

This is the egg of Strongyloides sp.

  • What phase is present in the egg?
  • Which is the infective phase?
A
  • Egg: rhabditiform L1
  • Infective: filariform L3
38
Q

This larva was found in the fresh feces of a dog.

  • What kind of larva is it?
  • Which species is most likely?
A
  • Rhabditiform L1
  • Strongyloides stercoralis

In this species, the egg hatches inside the host, and L1 larvae are shed in the feces.

39
Q

Describe the tail of the L3 of Strongyloides spp.

A

Notched tail.

(Looks like something took a bite out of it.)

40
Q

List the modes of infection for Strongyloides spp.

A

Skin penetration by L3 in the environment

Ingestion of L3 in environment (minor mode of infection)

Transmammary transmission of L3

41
Q

Can Strongyloides spp. go hypobiotic in dogs?

A

NO

Note that Strongyloides spp. can be hypobiotic in other species. This is an important source of transmammary infections.

42
Q

What will happen to a Strongyloides spp. L3 once it has been swallowed (either from the contaminated environment of from the colostrum)?

A

Penetrates mucosa, enters blood stream, moves to the lungs.

  • Penetrates alveoli, coughed up, swallowed.
  • Can also stay in blood to go hypobiotic in the tissues (except in dogs)

Adult parthenogenetic females live in the small intestine.

43
Q

What will happen to the L3 larva of Strongyloides spp. once it penetrates the skin?

A

Enters blood stream, moves to lungs.

Penetrates alveoli, coughed up, swallowed.

-Can also stay in blood to go hypobiotic in the tissues (except in dogs)

Adult parthenogenetic females live in the small intestine.

44
Q

In which Strongyloides species will you see L1 larvae instead of larvated eggs in fresh feces?

A

Strongyloides stercoralis

Found in humans and dogs

*Note that because the eggs hatch inside the body, autoinfection is possible.

45
Q

Describe how autoinfection occurs in Strongyloides stercoralis.

A
  • Female lays egg in host small intestine
  • Egg hatches in host and releases rhabditiform L1 (unique amongst the Strongyloides species)
  • Rhabditiform L1 develops into filariform L3 in host small intestine.
  • L3 penetrates mucosa, undergoes blood-lung migration, is swallowed, and develops into an adult female.
46
Q

In which host demographics are you most likely to find Strongyloides infections?

A

Young animals (transmammary transmission)

Immunocompromised hosts

47
Q

What is the name of the feline Strongyloides species?

Where does it live?

A
  • -Strongyloides tumefaciens*
  • -*Lives in large intestine

(all other Strongyloides species live in the small intestine)

48
Q

Which Strongyloides species infects primates, dogs, and rarely cats?

A

Strongyloides stercoralis

serpent taming (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions