Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

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
What is the common name of *Strongyloides* spp.?
Intestinal or minute thread worm
26
Which sex of *Strongyloides* spp. is parasitic?
Only females
27
Which phase of the life cycle is found inside in freshly-laid *Strongyloides* spp. eggs?
L1 (Except in *Strongyloides stercoralis*, in which the eggs hatch in the intestine and the L1 is shed in the feces)
28
What is unique about the *Strongyloides* spp. life cycle?
Has both free-living and parasitic generations
29
Describe the esophagus of an adult parasitic *Strongyloides* female.
Filariform esophagus (note that these worms are still rhabditids, but adult parasitic females do not have a rhabditiform esophagus)
30
What is the term for the parasitic generation of *Strongyloides* spp.?
Homogonic
31
In the homogonic phase of *Strongyloides* spp., where does the adult live within the host? (Recall that homogonic is the parasitic generation)
Small intestinal mucosa
32
Parthenogenetic *Strongyloides* spp. in the host lay eggs, which are deposited in the feces. What life phase is contained within the eggs?
Rhabditiform L1
33
What happens to the rhabditiform L1 of *Strongyloides* spp. once it is shed in the feces? (2 options)
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
What is the term for the free-living generation of *Strongyloides* spp.?
Heterogonic
35
Is the heterogonic generation of *Strongyloides* sp. sexual or parthenogenetic?
Sexual Rhabditiform males and females reproduce sexually to produce eggs with rhabditiform L1's. (Recall that adult parasitic females are parthenogenetic)
36
What are the two sources of infective filariform L3's in the *Strongyloides* sp. life cycle?
Eggs from parasitic parthogenetic females Eggs from sexual free-living adults
37
This is the egg of *Strongyloides* sp. - What phase is present in the egg? - Which is the infective phase?
- Egg: rhabditiform L1 - Infective: filariform L3
38
This larva was found in the fresh feces of a dog. - What kind of larva is it? - Which species is most likely?
- Rhabditiform L1 - *Strongyloides stercoralis* In this species, the egg hatches inside the host, and L1 larvae are shed in the feces.
39
Describe the tail of the L3 of *Strongyloides* spp.
Notched tail. (Looks like something took a bite out of it.)
40
List the modes of infection for *Strongyloides* spp.
Skin penetration by L3 in the environment Ingestion of L3 in environment (minor mode of infection) Transmammary transmission of L3
41
Can *Strongyloides* spp. go hypobiotic in dogs?
NO Note that *Strongyloides* spp. can be hypobiotic in other species. This is an important source of transmammary infections.
42
What will happen to a *Strongyloides* spp. L3 once it has been swallowed (either from the contaminated environment of from the colostrum)?
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
What will happen to the L3 larva of *Strongyloides* spp. once it penetrates the skin?
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
In which *Strongyloides* species will you see L1 larvae instead of larvated eggs in fresh feces?
*Strongyloides stercoralis* Found in humans and dogs \*Note that because the eggs hatch inside the body, autoinfection is possible.
45
Describe how autoinfection occurs in *Strongyloides stercoralis*.
* 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
In which host demographics are you most likely to find *Strongyloides* infections?
Young animals (transmammary transmission) Immunocompromised hosts
47
What is the name of the feline *Strongyloides* species? Where does it live?
* -Strongyloides tumefaciens* * -*Lives in large intestine (all other *Strongyloides* species live in the small intestine)
48
Which *Strongyloides* species infects primates, dogs, and rarely cats?
*Strongyloides stercoralis*

serpent taming (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions