Trypanosoma (Part 2) Flashcards
Where are T. cruzi trypomastigotes found?
Bloodstream PLASMA
Where are T. cruzi amastigotes found?
pseudocysts located in muscle or nerve cells, particularly of the myocardium or myenteric plexus where it replicates via binary fission = predilection site
How would I measure T. cruzi directly in order to make a diagnosis?
- Most sensitivity = xenodiagnosis
- Least sensitivity = thin smear (but can be used to identify species by morphology)
How would I measure T. cruzi indirectly?
Serological tests (ELISA)
- DNA probes
- PCR/DNA
For T. cruzi, sensitivity of serological tests increases as Chagas disease moves from acute to chronic (T/F)
False
-Decreases!!!
What are the hosts for T. b. gambiense?
- Primates
- Domestic pigs and dogs
What are the hosts for T.b. rhodesiense?
- Bushbuck and Hartebeest (Antelope)
What is the intermediate hosts for T.b. gambiense and rhodesiense?
Tsetse fly
Where do trypomastigotes occur for T.b. rhodesiense/gambiense?
- Blood
- Lymphatics
- Cerebrospinal fluid
Geographically, where does T.b. rhodesiense often distributed?
Central and East Africa
Geographically, where is T.b. gambiense often distributed?
West Africa, Zaire, Uganda and southern Sudan.
Where does the amastigote stage occur for T.b. gambiense/rhodesiense?
No tissue (amastigote) stage
Compare the infection time period of T.b gambiense to rhodesiense.
- T.b. rhodesiense readily infects in weeks
- T.b. gambiense infects chronically after months
When and where does the Tsetse fly often bite?
- Behind the ear
- During the day
Besides Tsetse fly bites, how else is T.b. gambiense/rhodesiense transmitted?
- Blood transfusions
- Congenital transmission
- Vertical transmission from mother to child
What are the clinical symptoms of an individual who has been bitten by a Tsetse fly?
- Local lesions
- Intermittent fever
- Weakness
- Anemia
- Progressive meningoencephalitis -> coma “Rhodesian sleeping sickness”
What are the clinical signs of an individual who has been bitten by a Tsetse fly?
- Trypanosomal Chancre
- Enlarged cervical lymph nodes (Winterbottom’s sign)
What are some direct methods for diagnosis of T.b. gambiense/rhodesiense?
- Smear for tryptomastigotes
- Aspirated lymph and CSF
- PCR/DNA probe
What are some indirect methods for diagnosis of T.b. gambiense/rhodesiense?
- Look for parasite products
- Serological tests: (ELISA - IgM)
What is the treatment for trypomastigotes outside the CNS of patients infected with T.b. gambiense/rhodesiense?
- Eflornathine and Suramin (main)
- (Early stages of infection)
What is the treatment given to patients in the late stages infected by T.b. gambiense/rhodesiense
Melarsoprol
treats brain and CNS
Why aren’t insecticides and effective control mechanism against T.b. gambiense/rhodesiense?
Does not kill pupae in soil
What are some methods of controlling T.b. gambiense/rhodesiense?
- Biconical traps with blue and black color attracts tsetse fly
- Reduction of human and animal reservoir by chemotherapy and chemoprophylaxis
