Trypanosoma (Part 2)

Question 1

Where are T. cruzi trypomastigotes found?

Answer 1

Bloodstream PLASMA

Question 2

Where are T. cruzi amastigotes found?

Answer 2

pseudocysts located in muscle or nerve cells, particularly of the myocardium or myenteric plexus where it replicates via binary fission = predilection site

Question 3

How would I measure T. cruzi directly in order to make a diagnosis?

Answer 3

• Most sensitivity = xenodiagnosis

- Least sensitivity = thin smear (but can be used to identify species by morphology)

Question 4

How would I measure T. cruzi indirectly?

Answer 4

Serological tests (ELISA)

• DNA probes
• PCR/DNA

Question 5

For T. cruzi, sensitivity of serological tests increases as Chagas disease moves from acute to chronic (T/F)

Answer 5

False

-Decreases!!!

Question 6

What are the hosts for T. b. gambiense?

Answer 6

• Primates

- Domestic pigs and dogs

Question 7

What are the hosts for T.b. rhodesiense?

Answer 7

• Bushbuck and Hartebeest (Antelope)

Question 8

What is the intermediate hosts for T.b. gambiense and rhodesiense?

Answer 8

Tsetse fly

Question 9

Where do trypomastigotes occur for T.b. rhodesiense/gambiense?

Answer 9

• Blood
• Lymphatics
• Cerebrospinal fluid

Question 10

Geographically, where does T.b. rhodesiense often distributed?

Answer 10

Central and East Africa

Question 11

Geographically, where is T.b. gambiense often distributed?

Answer 11

West Africa, Zaire, Uganda and southern Sudan.

Question 12

Where does the amastigote stage occur for T.b. gambiense/rhodesiense?

Answer 12

No tissue (amastigote) stage

Question 13

Compare the infection time period of T.b gambiense to rhodesiense.

Answer 13

• T.b. rhodesiense readily infects in weeks

- T.b. gambiense infects chronically after months

Question 14

When and where does the Tsetse fly often bite?

Answer 14

• Behind the ear

- During the day

Question 15

Besides Tsetse fly bites, how else is T.b. gambiense/rhodesiense transmitted?

Answer 15

• Blood transfusions
• Congenital transmission
• Vertical transmission from mother to child

Question 16

What are the clinical symptoms of an individual who has been bitten by a Tsetse fly?

Answer 16

• Local lesions
• Intermittent fever
• Weakness
• Anemia
• Progressive meningoencephalitis -> coma “Rhodesian sleeping sickness”

Question 17

What are the clinical signs of an individual who has been bitten by a Tsetse fly?

Answer 17

• Trypanosomal Chancre

- Enlarged cervical lymph nodes (Winterbottom’s sign)

Question 18

What are some direct methods for diagnosis of T.b. gambiense/rhodesiense?

Answer 18

• Smear for tryptomastigotes
• Aspirated lymph and CSF
• PCR/DNA probe

Question 19

What are some indirect methods for diagnosis of T.b. gambiense/rhodesiense?

Answer 19

• Look for parasite products

- Serological tests: (ELISA - IgM)

Question 20

What is the treatment for trypomastigotes outside the CNS of patients infected with T.b. gambiense/rhodesiense?

Answer 20

• Eflornathine and Suramin (main)

- (Early stages of infection)

Question 21

What is the treatment given to patients in the late stages infected by T.b. gambiense/rhodesiense

Answer 21

Melarsoprol

treats brain and CNS

Question 22

Why aren’t insecticides and effective control mechanism against T.b. gambiense/rhodesiense?

Answer 22

Does not kill pupae in soil

Question 23

What are some methods of controlling T.b. gambiense/rhodesiense?

Answer 23

• Biconical traps with blue and black color attracts tsetse fly
• Reduction of human and animal reservoir by chemotherapy and chemoprophylaxis