Brainscape's Knowledge GenomeTM

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


See full index

Y3 Parasitology > Toxoplasma gondii > Flashcards

Toxoplasma gondii Flashcards

1
Q

Toxoplasma gondii is the main cause of?

A

Abortion in sheep

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

What are the end results of asexual and sexual reproduction?

A

Asexual = multiplication of parasite numbers

Sexual reproduction = recombination of genetic material

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

What are some characteristics of an apical complex?

A
  • involved in host cell invasion
  • single celled
  • distinguishable by the conoid at the end of the parasite
  • contains: dense cell granules, microneme, rhoptry
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name the 3 stages of growth of the toxoplasma gondii parasite

A
  • Tachyzoite
  • Bradyzoite
  • Oocyst
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe a tachyzoite

A
  • Intracellular
  • Rapidly dividing
  • Crescent shaped - 2-6um
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe a bradyziote

A
  • Within a bradyzoite cyst
  • Neural or muscle tissue
  • Slow growing
  • Persistant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe an oocyst

A
  • Unsporulated oocyst passed in faeces
  • 12um
  • Sporulated oocyst => two sporocysts => 4 sporozoites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the definitive host of Toxoplasma gondii?

A

Cat

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

How do cats become infected with Toxoplasma?

A

Ingesting bradyzoite cysts in the tissues of prey

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the life cycle of Toxoplasma inside the definitive host

A
  • sexual cycle occurs in the small intestine

- unsporulated oocysts shed in faeces

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

How does infection of the intermediate host with toxoplasma occur?

A
  • Oocysts sporulate to two sporocysts and then to four sporozoites
  • these contaminate the environment before being ingested by any warm blooded mammal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the life cycle of Toxoplasma inside the intermediate host

A
  • sporozoite’s released and travel across the gut wall
  • develop into tachyzoites which replicate rapidly
  • differentiate into bradyzoites which form cysts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe toxoplasmosis in sheep

A
  • Transmission by ingestion of infective sporulated oocysts
  • Oocysts from cats that contaminate the pasture
  • No direct sheep-sheep transmission
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How many oocysts can be out put from a cat?

A

more than 10,000

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

How many oocysts does it take to cause abortion in a sheep?

A

1000

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

Do sheep show clinical signs of a toxoplasma infection?

A

No

17
Q

What are the clinical manifestations of toxoplasma in a pregnant sheep

A
  • Still births
  • Abortions
  • Mummifications
  • White, discrete lesions on cotyledons
18
Q

What are the consequences for the foetus and mother if toxoplasma infection occurs in the first 40 days of pregnancy?

A

Foetal death and reabsorption

Infertile ewe

19
Q

What are the consequences for the foetus and mother if toxoplasma infection occurs between day 40 and 110 of pregnancy?

A

Parasite becomes established in the placenta and foetus causing abortion

20
Q

What are the consequences for the foetus and mother if toxoplasma infection occurs from day 110 of pregnancy?

A

Parasite becomes established damaging the placenta and cotyledons
Congenital infection - brain damage and birth defects

21
Q

Describe how you would use serology to diagnose ovine toxoplasmosis

A

Antibody detection in serum or foetal fluids

  • Immunofluorescence antibody test (IFAT)
  • Agglutination tests
  • Dye test
22
Q

Describe how you would use histology to diagnose ovine toxoplasmosis

A
  • Cotyledons
  • Brain tissue
  • Non-suppurative inflammation: Infiltration of leukocytes, macrophages and monocytes which gives an indication of protozoal infection
23
Q

What management techniques can be implemented to control Toxoplasma-associated abortion in sheep?

A
  • Infection with Toxoplasma induces strong immunity
  • Introduce new stock well before tupping
  • Protect feedstuffs from access by cats
24
Q

How can you treat toxoplasma in sheep?

A
  • No way of treating infection
  • Dispose dead lambs and infected placentas
  • Disinfect contaminated pens
25
Q

Is there a vaccine available for Toxoplasma gondii?

A

Yes - Toxovax - vaccine to protect sheep against Toxoplasma abortion

26
Q

What is the main source of Toxoplasma infection for ewe

A

Oocysts shed by cats, contaminating pasture or feed.

27
Q

What advice would you give to a pregnant woman wanting to

(a) vaccinate ewes with Toxovax and
(b) around lambing?

A

(a) don’t administer the vaccine as there is a risk of accidental self-injection that could harm her baby
(b) avoid the lambing shed as a small risk of contracting infection through contaminated foetuses/placentae at lambing.

Y3 Parasitology (13 decks)

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