17. Protozoa (Plasmodium) Flashcards
what is one of the oldest diseases known to man?
Malaria
where does the name “malaria” come from?
the italian words mal’aria meaning bad air
was malaria in canada? where?
yes, in upper and lower canada and out into the prairies
where does malaria rank in “causes of death” for infectious pathogens?
third after HIV/AIDS and tuberculosis
how is malaria transmitted?
from person to person via the bite of a females Anopheles mosquito
in Plasmodium an intracellular or extracellular parasite?
obligate intracellular
what time of day does the female mosquito bite?
dusk and dawn
are all Anopheles species able to transmit the parasite?
no, only about 60 in 380
the accumulation of what spreads the disease?
water
what are the four parasite species that cause malaria in humans?
Plasmodium falciparum
Plasmodium vivax
Plasmodium malariae
Plasmodium ovale
which are the most common parasite species to cause malaria in humans?`
p. falciparum and p. vivax
what are the major features of P. falciparum?
- the most important species, responsible for ~50 of all malaria cases worldwide and nearly all morbidity and mortality from severe malaria
- found in the propics and sub-tropics
what are the major features of P. vivax?
- widest geographical distribution
- seen in tropical and sub-tropical areas, but rare in Africa
- estimated to cause 43% of all malaria cases in the world
what are the major features of P. ovale?
- relatively rarely encountered
- primarily seen in tropical Africa, especially in the west coast, but has been reported in South America and Asia
what are the major features of P. malariae?
- responsible for only 7% of malaria cases
- occurs mainly in sub-tropical climates
what other vertebrates are also infected by Plasmodium parasites?
- non-human primates
- rodents
- birds
- lizards
- ungulates
who is the DH of Plasmodium?
Anopheles mosquito
who is the IH of Plasmodium?
human
what is special about P. vivax and P. ovale?
they have a dormant liver stage: hypnozoite
what Plasmodium stage does the Anopheles mosquito inoculate the human with?
sporozoites
what happens to the sporozoites in the human, in the liver?
they mature into schizonts
what happens to the schizonts?
they rupture and release merozoites
what does the hypnozoite do?
it can persist in the liver and cause relapses by invading the bloodstream weeks or even years later
what is the liver replication stage called?
exo-erythrocytic schizogony