Parasites Flashcards
What are protozoa?
Unicellular eukaryotes.
What is the cyst form of a protozoa?
Tough protective layer outside plasma membrane to protect against inhospitable environments.
What is the trophozoite form of a protozoa?
Growing form without a cyst wall.
What do we call the cyst form of a protozoa when it is a sexually reproducing organism?
Oocyst.
What is a characteristic symptom of Entamoeba histolytica?
Bloody diarrhea.
Does Entamoeba histolytica have a cyst form?
Yes.
The cyst/oocyst form of some parasites have a high degree of ________ resistance. Why is this especially problematic?
chlorine.
Our drinking water is usually treated with chlorine so they can exist comfortably in tap water.
Why can some parasites (Entamoeba histolytica, Giardia lamblia, Trichomonas vaginalis) be treated with metronidazole (an antibiotic)?
They are anaerobic parasites and the antibiotic targets anaerobic organisms.
What is a major sign of giadiasis (“Beaver fever”, caused by Giardia lamblia)?
Flatulence (gas) & diarrhea.
Does Giardia lamblia have a cyst form?
Yes.
Giardia lambia can be found in _____ because it has a ________.
water, flagella.
Does Trichomonas vaginalis (“trich”) have a cyst form?
No.
How is Trichomonas vaginalis spread?
Person-to-person via sexual transmission.
Where can Trichomonas vaginalis be found?
In the vagina & male urethra.
What are symptoms of Trichomonas vaginalis?
Itching & inflammation of tissues.
Acanthamoeba are trophozoites in _____ and cysts in ____.
water, dust.
Acanthamoeba are often found in the ___, which is why they are often problematic for those who wear ______ ______.
eye, contact lenses.
What is the outcome of Acanthamoeba infection?
Vision or eye loss.
Cryptosporidium parvum reproduces ________, which means they have _______.
sexually, oocysts.
Where do we usually find Cytosporidium parvum?
Animals like cows, rats, dogs & cats.
How do people usually get Cytosporidium parvum?
Water contaminated with animal manure.
What is a characteristic symptom of infection by Cytosporidium parvum?
Chronic diarrhea.
Toxoplasma gondii is _________ reproducing, so they have an ______ form.
sexually, oocyst.
Where is Toxoplasma gondii usually found?
Cat feces.
How is Toxoplasma gondii usually acquired?
Eating uncooked meat with tissue cysts or contact with cat feces.
Which demographic of people is Toxoplasma gondii particularly dangerous for?
Pregnant women.
Trypanosoma are _____ parasites.
blood
How is Trypanosoma usually transmitted?
vectors - bugs.
What are the two types of Trypanosoma we need to know and to where are they endemic?
T. brucei gambienese/rhodesience in Africa.
T. cruzi in South America.
What is the vector of transmission for Leishmania?
The sandfly.
Describe the 3 different degrees of infection for Leishmania from most to least serious?
Visceral: affects internal organs.
Mucocutaneous: parasite eats cartilage.
Cutaneous: sores on skin.
How does Leishmania grow & avoid destruction by macrophages?
They live & develop in macrophages and affect the macrophage’s killing ability so they can grow safely.
Plasmodium species is the cause of _______.
malaria.
What are the 5 types of Plasmodium that we have to know?
- P. falciparum.
- P. malariae.
- P. ovale.
- P. vivax.
- P. knowlesii (new).
What is the most dangerous type of Plasmodium and why?
P. falciparum because it targets all ages of RBCs.
Why are symptoms of infection by P. falciparum?
Fevers & chills (toxic breakdown products of RBC destruction). Cerebral malaria (sequestration of parasites & RBCs blocking blood vessels & causing organ death). Anemia (due to lysis of RBCs). Kidney failure (too many Hemoglobin breakdown products).
Where is the focus of infection for Plasmodium?
The liver.
When do we take blood to test for Plasmodium?
Fever - highest chance of finding it at that time.
What are metazoa?
Multicellular organisms (helminths)
What are the 3 major groups of worms causing human infection?
Nematodes, trematodes & cestodes.
What are 2 characteristics of nematodes?
Round, have a complete digestive system.
What are the 2 categories of nematodes & nematode infection?
Eggs as the infective stage.
Larva as the infective stage.
Enterobius vermicularis is also known as _______.
Pinworm.
Pinworm has ____ as the infectious stage.
eggs.
Where do pinworms live?
Large intestine.
Where & when do female pinworms go to lay eggs?
The external skin of the anus at night.