Malaria Flashcards
2022 Malaria cases/deaths, most prevalent continent
247 million cases worldwide (2022)
619,000 estimated deaths
Africa accounts for 95% of cases and 96% of deaths
children <5 estimated 80% of all deaths in Africa
what are the 5 different plasmodium spp
falciparum - Africa, Asia, south America
vivax - Asia, SE Asia, South America
ovale - W Africa
malariae - worldwide
knowlesi - SE Asia
Malaria life cycle - two stages
Liver stage - mos injects parasite - sporozoites to the liver, marazoites go to the blood stage. then to trophozite, make changes to RBC membranes - sexual stage- gametozytes - then ingested by mosquito during feeding and continues
erythrocytic schizogony
RBC(mature schizont) ruptures>8-24 merozoites and debris enter bloodstream
debris - parasites +malaria toxin = inflammatory cytokine release > fever
schizogony timing by species
q 24h - P.knowlesi >Quotidian fever
q 48h - P.falcip, vivax, ovale > Tertian fever
q 72h - P.malariae > Quartan fever
*Due to synchronized release of parasites from the RBCs
falciparum clinical
can be severe, fatality rate up to 20%
rings and gametocytes in perph circ., normal RBC size.
prepatent 9-11 days
incubation 9-14 days
vivax clinica
parasitemia < 2%
dormant hypnozoites in liver > weeks to mos after infection
relapse timing is geographically variable and strain dependent
immature RBCs requires Duffy agn to bind
prepatent period: 11-13 d
incubation period 12-12 d and up to 6-12 mos
travel related malaria infection annually
~30,000
transmission risk
depends on temp, humidity, rainfall
temp 20-33 C
doesn’t occur in all parts of endemic countries
No transmission above 2500 m, during cold seasons, in deserts and in areas where transm is interrupted through control/elimination
generally - closer to equator, more likely to be year-round
determine risk for malaria
where
when
style and duration of travel
who (increased risk, pregnant, VFR, child, etc)
nighttime exposure and resistance patterns
% travelers who got malaria
57% did not have a travel visit
68% of VFRs did not have a visit
80% of children wer VFRs
pregnant or plan to become pregnant with malaria risk area for travel
1 - advise to avoid travel if possible
2 - chemoproph very important - mefloquine or chloroquine
how long does it take for malaria “immunity to wain?
6 months
mosquito repellents
DEET 30-35%
Picardin 20%
mosquito insecticide
Permethrin - treat clothing, tents, nets, etc
mosquito spatial repellents
aerosol spray, vaporizer device or smoldering coil-pyrethroid (eg metofluthrin or allethrin)
mosquito product not for <3 years old
oil of lemon eucalyptus
main goal of malaria prophylaxis
prevent death from P falciparum
P falciparum chloroquine resistance is everywhere except…
Caribbean, Central America(west of Panama Canal) and some countries in the Middle East
P falciparum mefloquine resistance areas
border Thailand with Burma and Cambodia
Western provinces of Cambodia
Eastern states of Burma and Burma-China border
Borders of Laos and Burma and adjacent Thai-Cambodian border and Southern Vietnam
P vivax chloroquine resistance
Papua New Guinea and Indonesia
malarone
> 98% efficacy
SE: abd pain, N,V, HA, mouth sores, rash
not for pregnant or kids < 5kg (11lb), or severe renal dz with creatinine < 30mL/min
warfarin dosing may need adjustment d/t proguanil
chloroquine and hydrochloroquine
weekly, at least a week prior and 4 weeks after
okay for pregnancy- all trimesters
SE: GI, HA, dizzy, blurred vision, pruritis
take with food
doxy
SE: GI - take with food, sit upright
esophageal ulceration, sun sens, candida vag.
not for pregnancy or children under 8yo
Mefloquine
efficacy PF, PV >90%
discontinuation rates 1-5%
okay for pregnancy
SE: GI, insomnia, abnormal dreams, depression, anxiety
severe neuropsych disorders leading to motor neuropathies- agitation, restless, mood changes, panic attacks
occasionally psych sxs continue for long time after d/c
mefloquine contraindications
active or recent hx depression, GAD, psychosis, schizophrenia or other major psyc disorders or seizures
also do not use with cardiac conduction abnromalities
moderate 1/200, severe 1/10,000
malaria med mode of action
malarone and primaquine are hepatic schizontacides
primaquine works on the hepatic hypnozoites
malarone, doxy, mefloquine act blood stage schizontacides
primaquine
Must check G6PD deficiency
no pregnancy
P vivax primary prophy or antirelapse tx (terminal prophy)
primary - 1-2 days before, daily and 7 d after
PART - for 14 days after leaving the area
tafenoquine
adults >16
primary prev- 3 days before leaving malaria area, then weekly until 1 wk after leaving the area
PART - presumptive antirelapse - 1 300 mg dose after leaving the malaria area
not for G6PD, pregnancy, nursing, keratopathy, not for psychotic disorder
stand by malaria treatment
reliable - consider for longer trips in case they are diagnosed with malaria
preferred are malarone or artemether-lumefantrine
hold chemoproph during SBET, resume after
malaria sxs
fever 6-10 hrs, HA, nausea, vomiting, abdominal pain, myalgia, tachycardia,
severe malaria mortality rate
20% even with good treatment
clinical: impaired consciousness
resp distress, circulatory collapse, convulsions,
pulm edema, abn bleeding, jaundice, hemoglobinuria
Lab: severe anemia, hypoglyc, acidosis, renal imp, hypercactemia, hyperprasitemia
severe malaria - early dx imperative
fever in returning travel is malaria until proven otherwise
thick and thin smears and a rapid test
repeat within 24 hours if negative
dx - falciparum vs non falciparum
get percent parasitemia
sever/complicated? then parental therapy and ICU
malaria treatments
oral: malarone, quinine +doxy and artemether/lumefantrine
parenteral: IV artesunate, IV quinine
no benefit to steroids
