PBL 2 Flashcards
outline the lifecycle of malaria between human and mosquito?
an infected female mosquito bits a person, injecting plasmodium parasites from their salivary glands into the blood stream. sporozoites pass to the liver where they multiply asexually in the hepatocytes. merozoites are released from hepatocytes In vesicles and move to the lungs where the vesicles eventually disintegrate freeing merozoites into the blood. they invade RBCs and multiply until the cell bursts- this cycle repeats causing fever each time
some merozoites develop into gametocytes that circulate the blood stream
when an uninfected mosquito bites an infected human it ingests gametocytes which will sexually reproduce to form an oocyst. oocysts eventually burst to release sporozoites into the mosquito and they then move to the salivary gland
what are the symptoms of malaria?
period cycles of fever every 48-72 hours headaches muscle aches cough high HR hepatomegaly splenomegaly nausea vomiting jaundice anaemia
outline the stages of the cyclic fever that occurs with malaria?
16-60 minutes of shivering and cold, 2-6 hours of fever flushing dry skin headache nausea and vomiting, 2-4 hour sweating stage as fever drops rapidly
what causes the period fever symptoms of malaria?
fever is cause whenever parasites are released from rupturing cells as they activate pyrogenic cytokines
why does malaria cause jaundice?
liver dysfunction and intravascular haemolysis
how can malaria be transmitted?
bites of infective female mosquitos
blood transfusions
using contaminated needles and syringes
form mother to child
outline the ABCD approach to prophylaxis of malaria?
awareness of risk
bite prevention
checking if you need antimalarials
diagnosis
how can you get partially naturally acquired immunity to malaria?
over years of exposure to infections and acquisitions of anti-malarial antibodies
this can take up to 20 years
what can change the choosing strategy for which antimalarial to give for malaria treatment?
the type of malaria parasite
severity of symptoms
age
pregnancy
what is the first line drug choice to treat malaria?
chloroquine phosphate
why might cloroquine phosphate not be able to be used?
because some areas of the world have malaria strains that have developed resistance
which drug do you give if the malaria strain is chloroquine phosphate resistant?
ACTs
artemisinin-based combination therapies
how does chloroquine phosphate work?
it inhibits heme polymerase which converts toxic heme to non-toxic hemazoin = accumulation of toxic free heme within parasite
how do ACTs work?
they kill the parasite through many steps but free radicals eventually end up damaging susceptible proteins
what is pyrexia?
having a temperature above the normal range due to an increase in the body’s temperature set point
