Life cycle Trypanosoma cruzi Flashcards
What is the classification of Trypanosoma cruzi?
Protozoa in the category trypomastigotes
How is Trypanosoma cruzi transmitted?
Through a vector of a Triatomine bug (kissing bug). These are active during the night. The triatomine bug bites and leaves urine on the skin. The parasite resides in the urine and goes into the body through the bite of the bug when the human smears this urine in when scratching.
What are the steps of the Trypanosoma cruzi lifecycle in the human host?
- Triatomine bug takes a blood meal in vertebrae’s (humans) and passes metacyclic trypomastigotes in feces, trypomastigotes enter bite wound or mucosal membrane, such as the conjunctiva (eye).
- Metacyclic trypomastigotes penetrate various cells at bite wound site. Inside cells they transform into amastigotes.
- Amastigotes multiply by binary fission in cells (asexual) of infected tissues.
- The new intracellular transform into trypomastigotes and burst out of the cell and enter back into the bloodstream. Here It can infect other cells and transform into intracellular amastigotes in new infection sides or continue the life cycle outside of the human host
What are the lifecycle steps of Trypanosoma cruzi lifecycle in the triatomine bug?
- The triatomine bug takes a blood meal and trypomastigotes are ingested by the triatomine bug.
- Trypomatsigotes are broken down in the stomach of the bug. The surviving trypomastigotes transform into epimastigotes and arrive to the midgut
- In the midgut of the bug they multiply
- In the midgut the transformation from non infective epimastigotes to infective metacyclic trypomastigotes takes place. After this process they can bite new hosts and infect them again.
What type of life cycle does Trypanosoma cruzi have?
Indirect lifecycle
What are the definitive host and or intermediate host host for Trypanosoma Cruzi?
Human is the intermediate host
Triatomine bug is the intermediate host
What is the reservoir for Trypanosoma Cruzi?
Armadillos possums racoons woodrats other rodents and domestic dogs.
What are the symptoms of the acute phase of Trypanosoma cruzi infection?
often asymptomatic but symptoms can be fatigue, fever, body ache, diarrhea, vomiting, Romana’s sign (swelling of the eyelid at the side of the bite). High number of parasites in the blood
It’s not self-limiting so without treatment it will become chronic
What are the symptoms of the chronic phase of Trypanosoma Cruzi infection?
often asymptomatic, but symptoms can be gastrointestinal complication, cardiac complications.
Where is trypanosoma cruzi endemic?
Middle and south-america
How is Trypanosoma cruzi diagnosed during the acute phase?
Detect parasites in the bloodstream via microscopy, molecular diagnosis and PCR
How is Trypanosoma Cruzi diagnosed during the chronic phase?
detect antibodies against the parasite via serological tests like enzyme immunoassay, immunoblot and IFA
The standard approach is to use 2 or more different tests that looks at multiple antibodies or antigens. You can look for trypomastigotes in the bloodstream or intracellular amastigotes.
