Lecture 28 - Intro to parasitology Flashcards
(40 cards)
what are protozoa?
single celled eukaryotes
are protozoa more like us or bacteria and fungi?
us
true or false, there are a lot of protozoal diseases
false, there arent many when compared to bacteria
describe Giardia lamblia
infects the gut of animals that drank contaminated water
surface infection of enterocytes called giardiasis
what are the symptoms of giardia lamblia infection?
watery diarrhoea, minimal systemic upset (no fever or lethargy)
true or false, giardia lamblia infects the inside of the enterocytes
false, it causes a surface infection of the enterocytes, so not inside the cell
how does giardia lamblia infect the surface of enterocytes
they are ingested as a cyst, sheds the cyst, trophozoites graze on the microvilli in the gut and are excreted in feces and forms a cyst again for protection
true or false, giardia lamblia infect the large intestine and cause diarrhoea
false, they only work in the small intestine
what is the diagnosis treatment for giardia?
diagnosis: observation of cysts in a stained sample under microscope
treatment: metronidazole at 500mg orally for 7 days normally clears infection
true or false, antibiotics are given to people infected with giardia lamblia
true, such as metronidazole
describe toxoplasma gondii
source: oocysts excreted in cat feces (all cat types, lions)
transmission: ingestion of feces or tissues (muscle) with bradyzoites or tachyzoites
cause tissue infection with bradyzoites and tachyzoites
how do cats get infected with toxoplasma gondii
by eating tissues with bradyzoites or tachyzoites
why do expeecting mothers have to be aware of toxoplasma gondii?
because it is one of the few infections that the tachyzoites can cross the placenta and infect the fetus in the uterus
when is a mother more likely to infect her fetus with toxoplasma gondii?
when she has never encountered toxoplasma gondii before, so more is circulating in blood
describe the toxoplasmosis disease
30% of people infected, usually acquired in childhood, minor symptoms, ends up as a persistent asymptomatic lifelong infection
when can toxoplasmosis cause severe infection
in fetus if the mothers primary maternal infection is during pregnancy
true or false, toxoplasma gondii can reactivate and cause illness when there is immunosupression
true, such as toxoplasma brain abscesses in people with AIDS
what is retinal toxoplasmosis?
from a congenital infection of toxoplasma gondii, where there is scarred retinal tissue from a toxoplasma gondii infection during pregnancy
how do we diagnose toxoplasmosis?
serology showing IgM or IgG antibodies positive for toxoplasma gondii
- PCR for DNA in CSF
- radiology
- Opthalmoscopy appearances
what does it mean if we are diagnosing toxoplasmosis and the patient binds either IgM or IgG
IgM = acute infection
IgG = chronic infection
what is the treatment for toxoplasmosis of a healthy person?
none for an acute infection
what is the treatment for toxoplasmosis brain abscesses in AIDS?
sulphadiazine + pyramethamine
when are mothers at most risk of passing toxoplasma gondii onto their children?
when there is an acute infection, so IgM presence in her blood.
- new infection
what is the most problematic protozoa in the world?
plasmodium falciparum
plasmodium vivax
- causes malaria
