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51 Cards in this Set
- Front
- Back
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What causes Chagas disease?
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Trypanosoma cruzi
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Where does Chagas disease occur?
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Central and South America
Also southern United States Occurs mostly in rural areas and poor suburbs |
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What is the reservoir of chagas?
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Domestic animals
Rodents Bats Armadillos |
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What form of Tryp cruzi was found in the cone-nosed bugs?
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Epimastigote
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What causes Chagas disease?
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Trypanosoma cruzi
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Where does Chagas disease occur?
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Central and South America
Also southern United States Occurs mostly in rural areas and poor suburbs |
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What is the reservoir of chagas?
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Domestic animals
Rodents Bats Armadillos |
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What form of Tryp cruzi was found in the cone-nosed bugs?
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Epimastigote
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What are the different forms Tryp can be found in?
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Amastigote
Epimastigote Trypomastigote Metracyclic trypomastigote |
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Describe the amastigote
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Very round
Nucleus near the side Has a biephoroplast |
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Describe the amastigote
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Very round
Nucleus near the side Has a biephoroplast |
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Describe the epimastigote
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More elongates
Nucleus still on one side Small flagella starts to develop |
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Describe the tripomastigote
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Larger than the epimastigote
Nucleus more centeres Flagella gets longer |
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Describe the metracyclic trypomastigote
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Elongated and curved
Nucleus centeres Have an ondulated mb Fully-formed flagella Flagella at the head |
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Why is the flagella at the head of the parasite?
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So that the parasite can be pulled
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How many cases of T. cruzi exist?
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At least 9 million (Latin America)
Many ppl don't know they're infected 100 million ppl are at risk |
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Compare and contrast T. brucei and T cruzi:
Origin |
Brucei: Africa
Cruzi: America |
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Compare and contrast T. brucei and T cruzi:
Form |
Brucei: stumpy-slender
Cruzi: slender |
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Compare and contrast T. brucei and T cruzi:
Posterior end |
B: Round-pointed
C: Pointed |
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Compare and contrast T. brucei and T cruzi:
Kinetoplast |
B: Small, terminal
C: Large, sub-terminal |
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Compare and contrast T. brucei and T cruzi:
Undulating mb |
B: 5-6 undulations
C: 2-3 undulations |
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Compare and contrast T. brucei and T cruzi:
Flagella |
B: Long
C: Short |
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Compare and contrast T. brucei and T cruzi:
Amastigote form |
B: none
C: Yes, when intracellular |
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Compare and contrast T. brucei and T cruzi:
Transmission |
B: Salivaria
C: Stercoraria |
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Is T. brucei ever intracellular?
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No, always extracellular
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Describe the life cycle of T. curzi
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Bug takes a blood meal
Puts feces into the wound it leaves, but this isn't a very efficient more of transmission, because the parasite has to get into the wound, so it can take many bites Parasite migrates once its in the blood as a trypomastigote Infects Macrophages Parasite becomes an amastigote Transforms in the mac and then escapes and gets into the tissue |
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What is the vector of this parasite?
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Redivid bugs (kissing bugs)
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What kind of bugs are reduviid bugs?
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Triatoma
Rhodnius |
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How does T. cruzi get into a non-phagocytic cell (i.e Fibroblast)?
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Recuits lytic enz so that the cell becomes fluid
Parasite can get into the surrounding phagocytic cell by destroying the mb |
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How does t. cruzi infect phagocytic cells?
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Modulating the receptor on the phagocytic cell surface
-->Entry is receptor-mediated |
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What is the incubation period of this parasite in humans?
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20 days
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What acute diseases does this parasite cause?
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Oedema
Anemia Local inflammation (Chagoma) adenopathies Fever Splenolomegaly Myocarditis -Possibly death (in 3-4 weeks, particularly for children under 5) |
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How long does it take to develop chronic and severe pathologies?
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10-20 years
Mainly found in adults |
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What are the chronic pathologies this parasite causes?
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Ventricular hypertrophy
Global cardiac failure (70% cardiac death in young adults of endemic areas) Megaoesophagos and Megacolon (fatal when patient can't swallow or accumulated feces) Flabbiness of organs |
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What is the most dangerous form of this parasite?
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Acute form
In Chagona, get a lot of inflammation If parasite load too high, parasite can go everywhere like the heart |
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What happens in Chagas's cardiopathy?
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Marked reduction of nerve fiber
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What can trypanosoma do if it gets to brain tissue?
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form Pseudocysts
Not all strains of T. cruzi can go into the brain though |
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What are the stages of Chagasic Oesophagopathy?
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Normal
Hypertrophy and dilatation Megaoesophagus |
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how does T. cruzi exploit host cell fct?
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Modulates NO production
Favors escape of trypomastigotes from macrophages |
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What does the parasite do to IFN-y?
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Exacerbates it and inactivates it
.: Inactivates immunoproteasome formation This helps parasite to escape the mac and infect other cells |
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What is the result of IFN-y inactivation?
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Inhibit Ag presentation a bit
Infected cells have a reduced production of important cytokines/subunits |
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What is the result of inhibiting MHV-1 dependent AP?
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Avoid activation of CD8+ cells
Also inhibits activation of CTL-mediated killing |
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Why would the parasite want to favor IFN-y production?
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Inc the amount of NO, so that it can escape
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What diagnostic can be used in the acute phase of parasite infection?
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1) Search for parasite in the blood:
-Thick blood slide -Hemoculture -Culture in NNN media -Inoculation to mouse 2) Xenodiagnostic |
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What diagnostic can be used for parasites in the chronic infection stage?
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1) Serology: immunofluorescence
2) PCR: molecular diagnostic 3) Histology: immunofluorescence |
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What chemotherapeutic treatment can be used in the acute phase?
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Nifurtimox
Benznidazole Possibly Amphotericin B |
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Describe Nifurtimox
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Can be Lampit or Radanil
Discontinued in 1991, because of poor response to treatment Could only kill extracellular parasites |
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Describe Benznidazole
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Rochagan
Drug of choice Has some side effects |
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Why would amphotericin B be used?
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Can target intracellular parasites
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Are there any chenotherapeutic treatments for intermediate and chronic phases of parasite infection?
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Yes, but they are controversial and only used if the person is symptomatic
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How can this parasitic infection be prevented?
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Bug control with insecticides (Pyretroids)
Screen blood for transfusion, mix blood with gentian violet to kill the parasite Organ tranplantation well monitored for parasite Detection and treatment of congenital transmission Better housing using modern material No vaccine yet |
