Parasite III

Question 1

4 malaria species that infect humans

Answer 1

plasmodium falciparum
plasmodium malariae
plasmodium vivax
plasmodium ovale

Question 2

which one of the malaria species are RBCs not enlarged

Answer 2

p. falciparum and p. malariae

Question 3

which malaria species have hypnozoites in the liver and what does it do?

Answer 3

p. vivax and p. ovale
they are sleeping sporozoites that go into the liver and remain dormant for 20-30 years and then reactivate causing malaria recurrence

Question 4

cycle in anophele

Answer 4

mosquito ingests blood meal with gametocytes (only stage transmissible to vector) –> in gut of anophele, it takes 5 days to convert gametocyte to sporozoites –> sporozoites migrate to salivary gland of anophele where it bites a human at night and inoculates them with sporozoites –> migrates to liver where it takes 8 days to become hypnozoite –> released as merozoites from liver into RBC to become trophozoite –> becomes erythrocytic schizont in 36 hours –> released as gametocyte

Question 5

describe plasmodium vivax

Answer 5

developing and thick (signet) ring form; enlarged RBCs

Question 6

what are the three symptom stage in malaria

Answer 6

cold stage: skin dry, pale and cold, rapid pulse and low volume, lasts 1 hr

hot stage: temp high, pulse rapid, last 2-6 hours

sweating: last 2-4 hrs

Question 7

specific symptoms for plasmodium falciparum

Answer 7

microcirculatory arrest, cerebral malaria –> retinal hemorrhages, coma, coma with eyes open but unseeing, decerebrate and decorticate rigidity, dysconjugate gaze

Question 8

why do we get cerebral malaria in plasmodium falciparum

Answer 8

P. falciparum schizonts adhere to endothelial endothelium of brain

Question 9

population more susceptible to malaria

Answer 9

pregnant women because mosquitoes are really attracted to them

Question 10

treatment for plasmodium falciparum

Answer 10

• quinine or quinadine (IV quinine): used as a reserve drug and treats all blood stages
• artemether/lumefantrine
• those that are chloroquine resistant you will use combination drug of –> sulfadoxine/pyramethamine/meflaquine

Question 11

treatment for plasmodium malariae

Answer 11

chloroquine

Question 12

treament for plasmodium vivax/ovale

Answer 12

chloroquine for the blood stages which it destroys all of

primaquine for the hypnozoites in the liver

Question 13

prophylactic drug for malaria

Answer 13

meflaquine (lariam), doxycycline, chloroquine (aralen), malarone (atavaquone and proguanil)

Question 14

how does the heterozygote for sickle cell anemia lead to survival advantage against malaria

Answer 14

infected RBCs sequestered deep in the RES – exposed to low O2 tension permits K+ loss –> leads to low pH which inhibits parasite growth