american trypanosomes Flashcards
What is the scientific name of the american trypanosome?
Trypanosoma cruzi
what transmits T. cruzi?
reduviid bug (kisssing bug)
What disease is associated with T. cruzi?
Chagas disease.
What is the story relating the discovery of chagas disease?
carlos chagas was a brazilian medical student that discovered the disease in 1910. He had been sent to work on an antimalarial campaign and discovered it. He is the only researcher that completely described the disease (pathogen, vector, host, clinical manifestations and epidemiology)
How does T. cruzi differ from african trypanosomes.
have amastigote stage in human.
What can T. cruzi infect?
nearly all species of mammals native to south and central america
What are some of the other ways to get infected? (instead of getting bitten)
consuming uncooked food contaminated with feces from the reduviid bug. Congenital transmission Blood transfusion organ transplantation accidental lab exposure.
Who is at risk at getting chagas disease? how many people have it?
100 million people in south and central america in 21 countries
16-18 million people have it
Where do the metacyclic trypomastigotes develop in the kissing bug?
hind gut
Describe the symptoms of chagas disease.
Primary lesion: bite consists of raised, flat plaque.
Acute stage: appears 7-14 days after bite. restlessness, sleeplessness, malaise, exhaustion, chills, fever and bone/muscle pains, romanas sign, rash/petechiae. sometimes accompanied by serious pericarditis and endocarditis. usually not recognized and resolves.
Chronic: alternating periods of relapse. abnormal function of hollow organs particularly heart, esophagus, and colon. leads to megaesophagus and megacolon.
What is ramanas sign?
swelling on one eye.
What causes megacolon and megaesophagus?
damage usually done by amastigotes. They release a neurotoxin affecting the cells ability to contract. affects the myenteric plexus which results in loss of muslce tone and enlargement.
Why isnt treatment very effective?
most early stage infections are asymptomatic and by the time someone develops chronic chagas treatment is no longer effective. also treatment is expensive.
What is the most effective way to combat chagas?
control of the vector.
What are the 2 drugs used to treat chagas?
Nifurtimox and benznidazole.
problem with them is that they only treat early infections not chronic infections. both increase oxidative stress of the parasite which leads to death or inhibition of growth.
