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Lecture 9

Lecture 9 notes: Malaria and AIDS orphans in Africa LECTURE NOTES AND SUPPLEMENTARY READING NOTES


Department
Health Studies
Course Code
HLTC23H3
Professor
Jason Ramsay
Lecture
9

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Lecture 9: Malaria and AIDS orphans in Africa
July 16, 2012
-most dangerous animals in perspective:
-venomous snakes @ 250,000 fatalities/year
-scorpions @ 2000 fatalities/year
-big cats @ 800 fatalities/year
-crocodiles @ 800 fatalities/year
-mosquitos @ 1-3 million fatalities/year
-plasmodium falciparum:
-strain of malaria that is particularly virulent
-appears to directly affect the central nervous system
-can cause neurological sequelae and epilepsy
-sequelae = a condition that is the consequence of a previous disease or injury
-most common form of malaria occurs 85% in sub-Saharan Africa
-malaria in context:
-350-500 million infections in humans
-one to three million deaths annually
-has killed more people than all wars and other plagues combined
-transmitted by Anopheles mosquitos
-vaccination efforts have failed
-famous author Wilbur Smith: I WAS BORN OF BRITISH STOCK ON JANUARY 9, 1933 IN NORTHERN
RHODESIA, NOW ZAMBIA, IN CENTRAL AFRICA. As an infant of eighteen months I was struck down by
cerebral malaria, delirious for ten days. The doctors told my parents that it was probably better if I died,
because if I survived I would be brain damaged. Despite the primitive medical facilities available in Africa
in those days, their prognosis proved correct; I survived and am now only mildly crazy.”
-pathogenesis:
-the Protozoan parasites live inside cells, where they are largely hidden from the immune
response
-infection has a profound effect on the immune system and can cause immune suppression
-dendritic cells suffer a maturation defect following interaction with infected erythrocytes and
become unable to induce protective liver-stage immunity

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-endemic areas for malaria (found esp. around equator):
-treatment:
-malaria is now tolerant of older treatments:
-quinine-based (gin and tonic)
-sulfadoxine pyrimetharine
-artimisinin (China) is now widely used
-7-day course is recommended and followup and monitoring recommended
-malaria in kids:
-CNS manifestations:
-severe infection + cerebral malaria
-severe infection + hypoglycemia
-hypoglycemia is induced by quinine
-severe anemia
-high fever
-drug induced behavioural changes
-neurocognitive morbidity of malaria:
-previously, malaria was considered mainly in terms of mortalityor how many people it killed
each year
-now research shows that besides mortality, it also has a high rate of morbidity

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-morbidity is an epidemiological word that is used to describe the burden of a disease on the
person infected with it
-so why has it taken so long to find out that malaria has a high morbidity, and that it has neurocognitive
sequelae?
-90-10 problem: (90% of research funding is spent on 10% of the diseases in the world
-or 90% is spent on 10% of the world’s population
-research has been spotty and poorly conducted
-the neurocognitive impairment study:
-authors estimate that approximately 188.6 million children in exposure/transmission zones for
cerebral malaria (CM)
-case fatalities, even under ideal clinical management are very high
-an estimated rate of children within easy reach of a hospital is less than 1/1000
-prom complex computations, they estimate that approx. 59-66,000 survivors of CM per year
-gross swelling and vascular constriction leading to severe hypertension
-systematic review:
-the authors conducted a systematic review of published papers to gain insights into the
neurocognitive sequelae of CM
-systematic review is special means of identifying trends from analysing results of many datasets
-what were the admitting symptoms:
-severe anemia, respiratory distress, recurrent convulsions, loss of consciousness
-how many have neurological sequelae?
-estimated that @ 10% of neurological problems following discharge
-some are seen at the time of discharge, others appear much later
-however, they could deduce the following:
-4.4 odds that there were epileptic symptoms
-24% had at least one impairment
-this places the estimated # of survivors with persistent neurological impairment @
1300-7500 per year
-limitations of the studies:
1) differences in definitions of neurological sequelae
2) differences in clinical complications
3) selection bias: studies are selective about who they enroll
4) differences in assessment: hinges on the ability of researchers to identity
5) confounding factors:
-premorbid condition of the child
-concurrent factors, such as iron deficiency
-changes with time in presentation of symptoms
-so what do we know?
-in Africa, there is a little accurate data to estimate the burden of neurocognitive impairment
caused by malaria
-based on data, approximately 1000 children per year are left with neurological sequelae
-this means that CM sequelae may be one of the most important causes of acquired disability in
Africa
-what does all this mean?
-there is a highly preventable epidemic of a chronic disease that occurs early in life and may
manifest throughout life
-treatment is relatively costly:$20-$30 US per year (something like $2000-3000 for Canadians)
-these children with motor impairment are unlikely to attend school
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