Parasites Flashcards
In a protozoa what is the name of the replicating form and the inactive form?
Replicating form is trophozoite
Inactive is cyst
What are the four types of protozoa? How are they classified?
Amoebas, Flagellates, Ciliates, Sporozoans
Classified by locomotion
What parasites covered in class are amoebas?
E. histolytica
What parasites covered in class are flagellates?
Giardia, Trichomonas vaginalis, T. cruzi, Leishmania
What parasites covered in class are sporozoans?
Plasmodium
How are protozoa and helminthes different?
Protozoa are single celled, microscopic, eukaryotes
Helminthes are multicellular, macroscopic and have organ systems and reproductive systems
What are the classes of helminthes? How are they classified?
Cestodes (tapeworms), Nematodes (roundworms),
Classified according to structure
What kind of genetic traits give someone protection from P. falciparum?
HbS and HbC (in heterozygous and homozygous state)
What kind of genetic trait gives some protection to P. vivex? What has this resulted in with the predominant form of malaria?
Lacking a Duffy RBC antigen is resistant to P. vivex infection
Shift to P. falciparum being the predominant form f malaria
What is the vector for plasmodium? What cells are the first to be infected? What happens when these first cells to be infected burst? What cells are infected second?
Mosquito- injects sporozoites when bite
Infect hepatocytes first then burst and release merozoites into the bloodstream. Infect RBC second
What is the malaria paraoxysm? How long does it typically last?
Cold stage, Hot stage, Sweating stage, followed by fatigue- typically lasts 6-10 hours but timing differs by species
What makes P. falciparum more fatal than the other plasmodium?
Can infect RBC of all ages, leads to expression of PfEMP-1 on infected RBC which allows it to bind to endothelium causing blockage and ischemia
During pregnancy what do RBC infected with P. falciparum bind to?
Chondroitin sulfate A (CSA) on the placenta
What is the vector for leishmanias?
Sand fly
What are the three different forms of leishmanias? How long after bite do they appear?
Cutaneous: skin sores, weeks afer bite
Visceral: internal organs, potentially life-threatening, months after bite
Mucosal: less common- can be from same species causing cutaneous
What parasite causes American trypanosomaiasis?
T. cruzi
What vector transmits T. cruzi? What is the mechanism?
Triatomine insects (aka kissing bugs)- get the parasite when mucus membrane, conjunctiva, or breaks in skin get infected with bug poop
What are the symptoms of Chagas disease? What parasite causes Chagas?
Acute: fever/swelling around the site of inoculation- usually eye
Can develop heart problems leading to sudden death, or an enlarged esophagus and colon leading to problems eating; T. cruzi
How are babesia transmitted to humans? Is it direct transmission?
Zoonotic disease- reservoir in one vertebrate that is then transferred to a invertebrate vector before infecting humans
Indirect transmission
What is the vector for babesia? What cells are infected?
Ticks; RBC
What are the symptoms of babesia?
Non-specific, flu-like; if symptomatic