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30 terms

Malaria

STUDY
PLAY
_______cases/year; ______ deaths/yr
300-500 million; 1-2 million
majority of cases/deaths
Sub-Saharan Africa
symptoms
fever, chills, flu-like, dizziness, coma, jaundice, renal failure
what causes malaria?
a bite for the Anopheles mosquito transmits the infection (Plasmodium)
Plasmodium
species that causes malaria; 4 types
P. falciparum
causes severe malaria and has a mortality rate of 20%
describe the life cycle of the Plasmodium parasite
Anopheles mosquito bites human and passes sporozoites of the malaria parasite - the sporozoites travel via blood to the liver where they infect liver cells & release morozoites into blood and they infect RBCs - infected RBCs lyse, more are infected and merozoites develop into gemetocytes that are ingested when another mosquito comes along - inside mosquitos gut gametocytes become gametes which are fertilized and zygote forms - meiosis - oocyst - oocyst releases sporozoites and cycle repeats
sporozoite
cell form of Plasmodium when it infects humans and enters the liver
merozoite
formed by sporozoites in host; turn into gametocytes
gametocytes
become gametes
what causes the malarial symptoms and peaks in fever
the merosoties entering circulation
why is studying mosquito evolution important?
studying mosquito evolution is important because it helps us understand and deal with the emergence of insecticide resistance
Sickle Cell Anemia
HbS heterozygotes are less prone to infection which causes balanced polymorphism b/c it causes incs in homozygotes for HbS do to its heterozygote advantage
what causes sickle cell anemia
codon change w/in beta-globin gene from GAG to GTG (glutamine to valine) which causes the RBCs to "sickle"
how can sickle cell anemia cause arterial damage
the sickled cells bind to and activate vessel lining which attracts other cells that build up in vessel, this can lead to an obstruction which causes O2 starvation (i.e. stroke)
Thallassemia
blood disorder; like sickle cell creates balanced polymorphism because people with this disease have some resistance to malaria
stagnant water
mosquitos like to breed in/near stagnant water
what steps were taken to eradicate malaria in the United States?
draining and oiling breeding areas, treating lg. pops w/quinines, screen installation, building dams to isolate mosquitos, improving cycle of poverty, and DDT
DDT
insecticide, freed 1/3 of victims worlwide from malaria by 1970; was eventually banned do to environmental concerns
Treatment
diff drugs and drug combos for diff plasmodium species and diff stages of the disease; most drugs contain some type of quinine derivative however many strains have become resistant; also the symptoms can be treated via liquids, sponge bath with cool h2o, etc
True/False: most deaths occur in women
False; most deaths occur in young children
bed nets
important for prevention, esp in Subsaharan Africa;
vaccination
current vaccine targets include 3 basic stages: sporo/merzoitc and gametocyte; there are also current clinical trials on prophylatic treatment (treating before it strikes)
fungus
current studies on treating the mosquitos with fungus so they cannot infect humans with plasmodium
how can plasmodium make humans more attractive to mosquitos?
by triggering changes in breath and body odors
what is the most common species in Subsharan Africa
Anopheles gambia
global warming and malaria
global warming may inc prevalence of malaria and cause outbreaks in previously eradicated areas
T/F: mosquitos are attracted to CO2
true
current goal is to reduce deaths by ____ by _____
1/2; 2015
Bill and Melinda Gates
campaign/goal for eradication; countries w/ wide use treated bed nets have seen great reductions in malaria deaths