Question

please help answer these 2 questions, it is microbiology. thank you.

9. List four measures that can be taken to prevent arboviral infections. 10. What feature of the life cycle of Trypanosoma brucei makes it difficult to develop a successful vaccine?

Answer 1

Trypanosoma brucei - African Sleeping Sickness

-trophozoites are flagella spindle-shaped cells

1. Tsetse fly has T. brucei in its salivary gland

2. vector transmission Tsetse fly bites human and injects trophozoite into blood (portal of entry)

3. Trophozoite replicates and moves into lymph and spinal fluid (extracellular)

4. Tsetse fly bites human and picks up T. brucei along with blood meal (portal of exit)

5. Develops into 2nd tophozoite stage in gut of fly

6. moves to salivary gland

7. Develop into trophozoite stage transmitted to humans

-symptoms - nervous system damage, sleep disorders, seizures, paralysis, slurred speech, coma and death (1 mo.)

-evades immune system by changing antigens so we can't develop antibodies - 2nd infection common

Vaccinations for Trypanosoma and Plasmodium are difficult to develop because there are changing antigens - can't develop antibodies and there are so many stages in the life cycle - natural immune response isn't great (hard to make memory cells)

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