Trypanosoma brucei

Question 1

Subspecies

Answer 1

• Trypanosoma brucei gambiense
• Trypanosoma brucei rhodiense
• Trypanosoma brucei brucei: affects animals

Question 2

Other names of T. brucei

Answer 2

• Human African Sleeping Sickness

• Human African Trypanosomiasis (HAT)

Question 3

Forms:

Answer 3

– Epimastigote

– Trypomastigote

Question 4

Tissues Affected:

Answer 4

Blood
lymph
spleen
CSF

Question 5

Multiplication

– Longitudinal binary fission:

Answer 5

Trypomastigote
Epimastigote

Question 6

Mode of Transmission

– Majority:

–

Answer 6

Vector borne

Blood transfusion
needle-prick
transplacental
organ transplantation

Question 7

• Infective Stage:

• Diagnostic Stage:

Answer 7

Metacyclic Trypomastigote

Trypomastigote

Question 8

Vector:

Answer 8

Tsetse Fly (Genus Glossina)

Question 9

T brucei gambiense:

– Western and Central Regions of Sub-Saharan Africa

– Primarily affects_____;

– Chronic type (95%)

– Reservoir Hosts: (3)

Answer 9

humans

dogs, pigs and sheep

Question 10

– Western and Central Regions of Sub-Saharan Africa

– Primarily affects humans;

– Chronic type (95%)

– Reservoir Hosts: dogs, pigs and sheep

Answer 10

T brucei gambiense

Question 11

– East Africa

– Primarily affects cattles and wild animals (Antelopes)

– Humans as accidental host

– Acute type and rapidly fatal (5%)

Answer 11

T brucei rhodesiense:

Question 12

• One wing rests directly on top of the other over their abdomen when resting

• Long proboscis extends directly forward

• Large thorax and abdomen that are shorter than wings

Answer 12

Tsetse Fly (Genus Glossina)

Question 13

Forms in the Life Cycle of Trypanosoma brucei

• Human:

–_______

• Vector:
________
________
________

Answer 13

Trypomastigote

– Procyclic Trypomastigote
– Epimastigote
– Metacyclic Trypomastigote

Question 14

• Polymorphic: slender or short stumpy form
• Flattened, fusiform shape
• Body: tapers anteriorly, blunt posteriorly

• Nucleus: centrally located with large central karyosome
• Kinetoplast: posterior end
• Undulating membrane with single flagellum

Answer 14

Trypomastigote

Question 15

• Body: tapers anteriorly, blunt posteriorly
• Nucleus: centrally located
• Kinetoplast: anterior to nucleus

Answer 15

Epimastigote

Question 16

When an infected fly bites a human or an animal, the_________ multiply rapidly into the blood and tissues (spleen, lymph nodes and CSF)

Answer 16

metacyclic trypomastigote

Question 17

Blood trypomastigote is ingested by the vector, it undergoes transformation in the midgut and are called__________

Answer 17

procyclic trypomastigotes

Question 18

After 15-20 days, the procyclic trypomastigotes transform into______&raquo_space;> migrate to the foregut then into the salivary glands

Answer 18

Epimastigotes

Question 19

The epimastigotes multiply in the salivary glands&raquo_space;> transform into the

Answer 19

Metacyclic Trypomastigotes

Question 20

Acute HAT:

manifest few weeks after the exposure to the vector

Answer 20

T. brucei rhodiense

Question 21

Chronic HAT:

manifest months or years after the exposure to the vector

Answer 21

T. brucei gambiense

Question 22

: long term persistence of parasites without clinical features

Answer 22

Trypanotolerance

Question 23

• Local, painful, pruritic, erythematous chancre located at the bite site progressing into eschar that spontaneously resolves within 23 weeks

– More common in Gambian sleeping sickness but can still occur in Rhodesian sleeping sickness

Answer 23

Initial Lesion

Question 24

Early Stage

• 1-6 months

•______________

– Parasite is proliferating in the blood and lymphatics

– Trypanids: circinate or serpiginous rashes on trunk and proximal extremities

•________ causing tissue damage

– Irregular and remittent fever, headache, joint pain, muscle pain, fatigue, malaise

– RARE: Disseminated intravascular coagulopathy, anemia, myocardial inflammation, renal insufficiency

Answer 24

Hemolymphatic Phase

Toxin is released

Question 25

EARLY STAGE

– Gambian trypanosomiasis

– Enlarged, nontender, rubbery posterior cervical lymphadenopathy (sometimes in axillary and supraclavicular region)

Answer 25

Winterbottom’s Sign

Question 26

Late Phase

•_______\

• Involvement of CNS: brain, meninges

• Gambian: 3-10 months after initial infection

• Rhodesian: few weeks after initial infection

• Neurologic Symptoms: seizures, behavioral changes, apathy, headache, sleeping disturbances (daytime somnolence, nighttime insomnia), tremors, defect in speech/reflexes and even paralysis

Answer 26

Meningoencephalitic Phase

Question 27

Late Phase

•_______

– deep delayed hyperesthesia after a slight blow on a bony projection of the body (delayed bilateral pain out of proportion to extent of injury)

Answer 27

Kerandel’s Sign

Question 28

Late Phase

• In later stages, somnolence manifests followed by a deep coma then death

• Affected areas: frontal lobes, pons, medulla, perivascular areas

• Trypanosomes can evade the immune system through______

Answer 28

antigenic variation

Question 29

Progression of african tryponomiasis

Answer 29

Blood
Lymphatics
CNS

Death

Question 30

• Stages in Diagnosis:

________
• Immunologic (serologic) method
• Card Agglutination Test for Trypanosomiasis (CARD): preferred
________
• Direct visualization of trypomastigote in the blood or lymph (cervical node), Microhematocrit method,
________
• CSF Examination by lumbar puncture

Answer 30

1. Screening Test
2. Confirmatory Test
3. Staging

Question 31

• Particles coated with variant antigen of T. brucei complex PLUS Patient Blood = Agglutination

Answer 31

Card Agglutination Test for Trypanosomiasis (CATT)

Question 32

Confirmatory Test

• Demonstration of the______ in the blood, chancre, lymph node aspirate and CSF

– Usually done during the early stage

Answer 32

Trypomastigotes

Question 33

Other Tests in the Acute Phase

Answer 33

• Concentration Method: Microhematocrit

Question 34

Staging

•_______: recommended to all suspected cases of HAT

– Definitive: Trypanosomes in the CSF

– Pathognomonic: High IgM level (quantitative or qualitative test)

– Others:

• Increase cell count: >5/uL
• Increase opening pressure

– PCR

Answer 34

CSF Examination