Brainscape's Knowledge GenomeTM

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


See full index

DTM&H > African Trypanosomiasis > Flashcards

African Trypanosomiasis Flashcards

1
Q

Which 2 organisms are responsible for African trypanosomiasis in humans?

A

Trypanosoma Brucei Gambiense - T.b.gambiense

Trypanosoma Brucei Rhodesiense - T.b.rhodesiense

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

Are T.b.gambiense and T.b.rhodesiense morphologically different?

A

No - they are morphologically identical

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

What is African trypanosomiasis also known as?

A

Sleeping sickness

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

What proportion of African trypanosomiasis is caused by T.b.gambiense?

A

90%

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

What is the vector of African trypanosomiasis?

A

The Tetse fly

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

What is the incubation period of T.b.gambiense?

A

Months-years

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

What is the incubation period of T.b.rhodesiense?

A

3 days-3 weeks

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

How do T.b.gambiense and T.b.rhodesiense differ in terms of disease progression?

A

Rapidity/progressivity - T.b.rhodesiense causes a more acute disease, whereas T.b.gambiense tends to cause more protracted disease

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

What are the features of the Tetse fly?

A
  1. Wings that fold like scissors
  2. ‘Hatchet Cell’ appearance on folded wings
  3. Preference for biting large objects and moving objects
  4. Painful bite
  5. Preference for dark colours - tend to bite light-skinned individuals through dark clothing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How many new cases of African sleeping sickness are there per year?

A

100,000

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

Where in Africa does T.b.gambiense tend to occur?

A

Mostly the central rift valley of Africa - >70% of cases occurring in the DRC

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

Where in Africa does T.b.rhodesiense tend to occur?

A

Mainly in East Africa - particularly Tanzania and Uganda

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

Which type of Tetse flies tend to be the vector for T.b.gambiense?

A

G (glossina).palpalis
G.tachinoides
G.morsitans

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

Which type of Tetse flies tend to be the vector for T.b.rhodesiense?

A 
G (glossina).morsitans
G.pallidipes
G.fuscipes
G.swynnertoni
G.tachinoides (in SW Ethiopia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the type of trypanosomiasis that only effects domestic wild animals?

A

T.Brucei.Brucei

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

How often do Tetse flies blood feed?

A

Every 2-3 days

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

What is Winterbottom’s Sign?

A

Prominent LNs in the posterior triangle of the neck

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

What is the primary stage of African trypanosomiasis?

A

Trypanosomal chancre - red and inflamed local reaction at site of bite (not a guaranteed sign)

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

African trypanosomiasis caused by which organism is more likely to cause a trypanosomal chancre?

A

T.b.rhodesiense

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

What is the secondary stage of African trypanosomiasis?

A

Blood and LN involvement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the signs and Sx of secondary stage African trypanosomiasis caused by T.b.gambiense?

A 
Low-grade/recurrent fever
Bachkache/headache
Tachycardia
Circinate erythema rash
Transient facial oedema
Cervical lymphadenopathy (more so ++ that T.b.rhodesiense)
Anemia monocytosis
Liver ad spleen enlargement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the signs and Sx of secondary stage African trypanosomiasis caused by T.b.rhodesiense?

A 
High/persistent fever
Chills
Headache
Facial oedema
Serous effusion - pleural/pericardial
Myocarditis
Bone pain
Hepatitis
Purpura
Lymphadenopathy
23
Q

In which stage of the disease does death most often occur in T.b.rhodesiense?

A

Secondary stage

24
Q

What is the most common cause of death in T.b.rhodesiense?

A

Cardiac failure

25
Q

What is the tertiary stage of African trypanosomiasis?

A

CNS involvement

26
Q

How does the parasite gain access to the CNS?

A
  1. Across the choroid plexus

2. Transcytosis across endothelial cells

27
Q

What are the signs and Sx of tertiary African trypanosomiasis caused by T.b.gambiense?

A

Thick, adherent dura
Oedema and dilated ventricles
Generalised leptomeningitis
Progressive encephalitis (accounting for the characteristic affect on sleep/wake pattern)
Dementia
Focal signs uncommon
CSF is turbid with increased cells and protein

28
Q

What are the signs and Sx of tertiary African trypanosomiasis caused by T.b.rhodesiense?

A

Death has usually occurred by this stage

But if CNS involvement does occur, it tends to cause a rapidly progressive encephalitis, coma, followed by death

29
Q

What may happen if Tx is given by the time disease has progressed to CNS involvement, but that treatment is delayed?

A

Persistent intellectual impairment

30
Q

What is a characteristic histological sign of African trypanosomiasis?

A

Presence of moruluar cells in the brain and other organs

31
Q

What may it be important to do before treating African trypanosomiasis?

A

Any co-existing infection/anaemia - many advocate routine use of anti-malarials/anti-helminths before/alongside use of specific treatments

32
Q

Which drug can be used as a prophylactic agent in T.b.gambiense (but NOT T.b.rhodesiense)?

A

Pentamidine

33
Q

What is the 1st line treatment for T.b.gambiense that hasn’t crossed the BBB?

A

Pentamidine IV or IM

34
Q

Why should pentamidine ideally be given IV?

A

To avoid painful local reactions

35
Q

What are the side effects of pentamidine?

A

Syncope
Low BP
Hypoglycaemia

36
Q

What is an alternative treatment for T.b.gambiense?

A

Nifurtimox + eflorinithine

37
Q

What is the 1st line treatment for T.b.rhodesiense that hasn’t crossed the BBB?

A

Suramin IV

38
Q

What are the side effects of suramin?

A

Fever, proteinuria, nausea, idiosyncratic anaphylaxis

39
Q

What drug can be used in T.b.gambiense ONLY when there has been CNS involvement?

A

Eflorinithine IV

40
Q

What drug can be used in both types of African trypanosomiasis?

A

Metarsoprol IV

41
Q

What is metarsoprol and what is it’s side effects?

A

Trivalent arsenic compound - a serious encephalopathy in 2-10% with a fatality rate of approx. 50%

42
Q

What can be done to reduce the risk of developing the serious encephalopathy associated with metarsoprol?

A

Prophylactic steroids

43
Q

Why may using eflorinithine treatment be more preferable to metarsoprol in T.b.gambiense?

A

Much better side effect profile - GI upset and anaemia (but is more expensive)

44
Q

When can full cure assumed?

A

Only when a 2 year F/U has occurred

45
Q

How can African trypanosomiasis be diagnosed?

A
  • Gland puncture
  • Blood film - stained or unstained (more difficult to detect T.b.gambiense in blood in later stages of infection)
  • CSF (in CNS infection ) - either presence of trypanosomoes OR by cells >5mm OR increased protein. LP for CSF should only be taken after a few drug doses to reduce risk of X-infection from blood if infection not already in CSF
  • CATT (circulating antigen agglutination trypanosome test) - 30 minute result, finger-prick test - can only be used in T.b.gambiense
46
Q

What is the host reservoir in T.b.gambiense?

A

Humans

47
Q

What is the host reservoir in T.b.rhodesiense?

A

Antelope types species - esp. bushbucks

48
Q

How do Tetse flies become infective?

A
  • Takes blood meal on infective host that has trypanomastigotes
  • The trypanomastigotes then penetrate the peritrophic tube lining of the Tetse’s fly’s midgut, then the ectoperitrophic space where they multiple by fission, then moving to the proventriculus
  • Then travel to the salivary glands where they becomes epimastigotes
  • 20 days after initial blood meal, trypanomastigotes are present again within the salivary glands, making the Tetse fly infective fo the rest of it’s life (a few months)
49
Q

Why do epidemics of T.b.gambiense tend to occur, but not epidemics of T.b.rhodesiense?

A

T.b.rhodesiense has a more acute progression, leading to death, and therefore there is never a large enough human reservoir to infect Tetse flies, unlike T.b.gambiense which has a chronic course, providing a large reservoir

50
Q

In what habitat do the Tetse flies that act as a vector for T.b.gambiense tend to live?

A

In the shaded protection of forrest tunnels near waterways - why women, more involved in water collection, tend to be more commonly infected in T.b.gambiense

51
Q

In what habitat do Tetse flies that act as a vector for T.b.rhodesiense tend to live?

A

Although they breed in/near water - they traverse the forrest widely up to the fringe of the savannah - in search of the animals on which they feed - why men - hunters or honey collectors, tend to me commonly infected

52
Q

Then how is the T.b.gambiense Tetse fly vector controlled?

A

Clearance of the dense undergrowth of the forrest tunnels (loss of shade)

53
Q

Then how is the T.b.rhodesiense Tetse fly vector controlled?

A

Forrest margin pushed back 1-2km from habitation

54
Q

What are the other vector control methods?

A
  • Use of insecticide (requires knowledge of where Tetse flies settle)
  • Fly trapping methods

DTM&H (8 decks)

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