Trypanasomes Flashcards
What disease is caused by trypanasoma cruzi, and what is the vector?
Chagas disease, which is transmitted by triatomine bug
Summarise T. cruzi life cycle
Ingestion into mouth of bug from mammal blood Replicates in the bug, and leaves via defecation Mammal is infected via defecation, which is allowed to entrance through opening made during feeding Invades mammalian host cells
What are the two ways in which T. cruzi invades mammalian cells?
Passive- taken up during phagocytosis, and in the phage they can replicate and eventually burst the phage
Active- active invasion of mammalian cells
How does antigenic variation compare in mammals vs insects for Trypanasoma?
Much more antigen variation in mammal form compared to form in insects
What disease is caused by T. brucei, and what is the vector?
Human African trypanasomiasis (sleeping sickness), and it is transmitted by tsetse fly
Summarise T. brucei life cycle
Ingestion into bug from blood Not excreted (like cruzi)- after differentiation in fly, they move back into mouth Infection to mammal is via bite during feeding of fly
How does T brucei invade host cells?
It doesn’t! It is not intracellular; T brucei never enter host cells
What causes late stage disease of T brucei?
Entry of T brucei into the central nervous system- why it does this is unknown; it cannot transmit to other hosts when in brain due to thick skull
Main differences between cruzi and brucei
Disease- chagas vs trypanasomiasis Vector- triatomine bug vs tseste fly
Life cycle- reinfection through feces vs mouth
Cellular- intracellular vs exclusively extracellular
Late stage effects- autoimmunity, heart/digestive track vs CNS perturbation
