African Trypanosomiasis

Question 1

What are the two species of African trypanosomiasis?

Answer 1

T.Gambiense
T.Rhodisiense

Cannot differentiate the 2 species and also cannot differentiate from typansoma Cruzi.

Question 2

How do you Rx for T.Gambiense?

Answer 2

If not CNS disease: phexinidazole
If CNS involvement (>100WCC on LP): Eflornithene or nifurimox

Question 3

How do you Rx T.Rhodisiense?

Answer 3

CNS: melasoprol
Non CNS: suramin/pentadimine

Question 4

Overarching name for species causing African sleeping sickness?

Answer 4

Trypanosoma Brucei

Question 5

Infective stage?

Answer 5

Trypomastigote

Question 6

Vector for T. Brucei?

Answer 6

Tsetse flies

Question 7

Difference in presentation between he 2 species causing African sleeping sickness?

Answer 7

Gambiense: chronic CNS disease
Rhodesiense: acute disease

Question 8

infective stage of HAT?

Answer 8

trypomastigotes

Question 9

Most endemic area for T.Gambiense

Answer 9

DRC

Question 10

Most endemic areas for T.Rhodesiense

Answer 10

Uganda, Tanzania, Zambia, Malawi

Question 11

Clinical features of HAT

Answer 11

Initial: Trypanosomal chancre - very common in T.b.R (not really in T.b.G)
Early: Haemolymphatic
Late: Menigioencephalitic

Question 12

Incubation period for T.b.R?

Answer 12

10 days

Question 13

If bitten by a Tsetse fly, what proportion of people will be infected with T.b.R?

Answer 13

1%

Question 14

Diagnosis?

Answer 14

Trypanosoma Rhodesiense chancre

Question 15

T.b.Gambiense - clinical presentation?

Answer 15

Slowly progressive neurological disease!
1st stage:
Low-grade, intermittent fever, gradual onset
Winterbottom sign
Facial oedema, malnutrition
Pruritus
Rash - trypanid rash - rare
2nd stage: encephalitis

Question 16

T.b.Rhodesiense - clinical presentation?

Answer 16

Rapidly progressive
1st stage
Acute high fever
Lymphadenopathies
Edema
Rash, petechiae
Multi-organ failur

2nd stage: encephalitis

Question 17

What is this?

Answer 17

Winterbottoms sign
A posterior chain lymphadenopathy
T.b.Gambiense

Question 18

T.Gambiense - pattern of fever and illness?

Answer 18

Waxing and waning - cyclic partial clearance of the parasite burden

Question 19

Which species gets more meningoencephalitis?

Answer 19

Gambiense - chronic
Rhodisiense - acute
Pattern: global encephalitis

Question 20

CSF criteria for diagnosis of HAT?

Answer 20

Presence of tryps in CSF
Presence of > 5 leukocytes/μL (with confirmed trypanosomiasis from blood)

Soft criteria:
- high protein in CSF
- Mott cells

Question 21

Investigation of choice to differentiate between clinical stages of HAT?

Answer 21

Lumbar puncture

Question 22

Diagnosis of T. b. gambiense?

Answer 22

Serology (including CATT - rapid test)
If positive - blood smear, LN aspirate, CSF, concentration methods

Question 23

Diagnosis of T.b.Rhodesiense?

Answer 23

Positive blood smear - very sensitive (high parasite load)

Question 24

Agglutination test/lateral flow to diagnose Gambiense - sens and spec?

Answer 24

95%

Question 25

Time of diagnosis between two species?

Answer 25

Rhodesiense - stage 1, usually first 10 days
Gambiense - stage 2, up to 1 year until diagnosis

Question 26

Treatment of non CNS R.Gambiense - first stage?

Answer 26

Pentamidine IM 10/7
New guideline: Fexinidazole 10 days oral (not if <6 yrs old, trials not done)

Question 27

Treatment of CNS R.Gambiense - 2nd stage?

Answer 27

Eflornitine IV + Nifurtimox
Logistically difficult to administer - 4x a day

OR

Oral fexinidazole 10 days orally (New)

Question 28

What is NECT? When it is preferred?

Answer 28

Nifurtimox/Eflornitine combination therapy
T.b.Gambiense

If WCC in CSF >100 - give NECT

Question 29

Monitoring of response to Rx in Gambiense?

Answer 29

LP after 6 months

Question 30

Treatment of Rhodesiense first stage?

Answer 30

Suramin
Test dose (anaphylaxis big risk)

Question 31

Treatment of Rhodesiense

Answer 31

Melarsoprol plus prednisolone
Very toxic - arsenic - causes encephalitis