Parasitic Protozoa II Flashcards
Toxoplasmosis
- Caused by toxoplasma gondii
- Widespread infection causing flu-like symptoms
- Reactivated in immunocompromised
- Transplacental transmission leads to serious problems
- Intracellular parasite that can infect any cell
Transmission of toxo among animals
- Transmission from contaminating oocysts (cats) - come from birds or rats getting eaten by cats who get the tissue cysts, and then comes out as a fecal oocyst
- Eating improperly cooked meat, transfusions, etc.
Essentially you can either get the tissue cysts or fecal oocysts
If someone is seropositive for toxo long before getting pregnant, is the baby at risk for toxo?
No you should have immunity against toxo, and so the baby should be protected.
If the maternal infection of toxo is
Probably not, the risk is pretty high
If maternal infection of toxo occurs during the first trimester, what disease of the neonate is possible?
- miscarriage
- stillborn
- chorioretinitis, hydrocephalus, intracranial calcifications, hepatosplenomegaly, jaundice, fever, anemia
If maternal infection of toxo occurs during 3rd trimester, what might happen?
- baby will be asymptomatic at birth but may have more learning disabilities and neurological sequelae
Can you directly identify toxo?
No, it’s pretty difficult. Do serology and PCR
Prevention of toxo
- No vaccine
- Change litter daily if you own a cat
- Keep cat indoors
- Dont eat undercooked meat
Tachyzoites vs. Bradyyzoites
- Tachy = dividing forms in a cell
- Brady = dormant forms in a cell
Chagas disease
- Infection that causes an acute and chronic phase
- Caused by trypanosoma cruzi
- There is a blood and tissue form
- Transmission = via kissing bug bite, congenital, blood transfusion, organ transplant
Life cycle of Chcagas
- You or dog is infected
- Bloodstream form gets transmitted to kissing bug
- Kissing bug feeds on human - bites you and then poops so that when it itches and you scratch, you scratch the parasites into the open wound (almost all other vectors use saliva)
- Gets into blood - travels to muscle cells (heart and intestine are its favorites)
Acute Chagas presentation
Initially mild symptoms at site of inoculation and in blood phase (often asymptomatic)
Chronic Chagas presentation
Asymptomatic tissue phase in most, but 20-30% will develop heart abnormalities and dilated esophagus or colon (die of heart attack)
Triatomine
Kissing bug
What’s the problem with a serological test for Chagas?
Doesn’t tell you if you are actively infected, or if you have any of the muscle form.
Why is chronic Chagas harder to diagnose?
Trypomastigotes are not found in blood and so you have to do a biopsy or some faulty serology