Plasmodium Introduction Flashcards
What characteristics do members of the phylum Apicomplexa share?
- all parasitic
- apical complex
- complex life cycles
What is the function of each of the components of the apical complex?
rhoptries & micronemes - secretory organelles penetrating host cells
conoid & polar rings - structural
Worldwide, how many people are infected with & how many die from Plasmodium?
~200 million cases
~650,000 deaths
What are the 4 species of Plasmodium which infect humans?
- P. vivax
- P. ovale
- P. mlariae
- P. falciparaum
What species of mosquito transmits malaria?
Anophels
Is the mosquito male or female?
female
What stage of the parasite is infective to humans?
sporozoites
Why do sporozoites invade hepatocytes and no other cells?
binds specifically to receptors on hepatocytes
What is the exoerythrocytic cycle?
trophozoite feeds on host cell cytoplasm
schizogony - asexual reproduction
merozoites burst out of hepatocyte
How does the mosquito transmit the parasite to the human host?
takes a blood meal
Once the sporozoite invades the hepatocyte, it transforms into a __.
trophozoite
This stage feeds for approximately one week and then undergoes a process of asexual reproduction known as ___.
schizogony
What occurs in the two steps of schizogony?
- nuclear division
2. cytoplasmic division
This stage leaves the liver, enters the blood and initiates which cycle?
merozoite
Erythrocytic cycle
What is the function of MSP-1?
binds to proteins on RBC surface & orients apical complex to RBC membrane
How does the apical complex function during the invasion of a RBC?
secretions from apical complex push merozoite into RBC membrane forming a pit
creates parasitophorous vacuole
How did the signet ring stage get its name?
large food vacuole is main characteristic
What is hemozoin?
end product of trophooite’s digestion of host Hb
Does schizogony occur during the erythrocytic cycle?
yes
What is released when an infected RBC ruptures?
merozoites & hemozoine
What does synchrony mean in a malaria infection? How is this related to the fevers associated with infection?
in an infected individual merozoites develop at the same time & released of merozoites & hemozoin is at the same time
causes fever & chills
What is the fate of micro- and macrogametocytes?
ingested by mosquito
What stage of Plasmodium is infective to the vector?
gametocyte
What happens to the marcogametocyte in the vector?
nucleus shifts
macrogametocyte = female
Name and explain the process which the microgametocyte undergoes in the vector.
exflagellation - nucleus divides 8 daughter cells each develops member & flagellum 8 microgametes (males)
What 2 cells join during fertilization & which stage is produced?
microgamete + macrogamete = ookinete
Where does the ookinete go?
penetrates stomach wall
attaches to hemocoel side
Ookinete transforms into a(n) ___ on the hemocoel side of the mosquito stomach.
oocyst
How many sporozoites develop in one oocyst?
> 10,000
How do the sporozoites get to the salivary glands?
migrate
How does feeding behavoir change in an infected mosquito?
feeds more frequently
PITT
