• Plasmodium falciparum
• Plasmodium vivax
• Plasmodium ovale
• Plasmodium malariae

also monkey malaria (Plasmodium knowlesi)

• children (most deaths due to malaria are children below five)
• pregnant women

• mosquito vector
  • Anopheles genus
  • only female ones carry disease
  • they act as definitive host (sexual stage)
  • humans act as intermediate host (asexual stage)
• rarely transmitted via blood transfusion or vertical

1. in hepatocytes (then burst and go into blood stream)
2. in RBC (then burst and go infect other RBC's)

• parasites in liver can go into dormant stage and they can reactivate years later and start the infection (hypnozoite)

Most drugs we give for malaria dont treat this phase in liver

• P. flaciparum- young RBC's
• P. vivax- reticulocytes
• P. ovale- reticulocytes
• P. malariae- old RBC's

• caused by Plasmodium flaciparum
• aka severe malaria
• due to cytoadherance (parasite infected RBC's stick to sides of bv's in brain, other organs)

uncomplicated malaria

complicated malaria

• fever paraxysms (classical periodicity)
  • chills, then fever, then sweats
  • fever can be very high
  • accompanied by headache, nausea, vomitting
  • symptoms coincide with rupturing of RBC's
  • time course
    • every 2 days for P. vivax/ovale (tertian malaria)
    • every 3 days for P malariae (quartan malaria)
    • irregular w/P falciparum

• severe anemia
• cerebral malaria, leads to seizures, coma
• hypoglycemia
• hyperparasitemia
• respiratory distress/pulmonary edema
• renal failure- hemoglobinuria (black water fever due to increased Hb in blood stream giving you black piss)
• acidemia/acidosis
• circulatory failure/shock

rarely, vivax can cause splenic rupture that is fatal

• usually happens in adults
• non cardiogenic
• likely due to sequestration, cytokine rlease, increase capillary permeability, ARDS
• poor prognositc sign

• poor prognositic sign (esp. in kids w/ cerebral malaria)
• mechanism
  • suppress hepatic gluconeogenesis
  • increased tissue consumption
  • hyperinsulinemia from islet cell stimulation
• worsens with treatment with quinidine for severe malaria

• host factors
  • age (young age is risk)
  • genetic factors
  • pregnancy (increased risk)
  • travelers vs. people living in endemic arera (no one ever has full immunity)
• parasite factors
  • P falciparuym causes complicated malaria
• transmission intensity: year round vs. seasonal vs. epidemic

• resistance is incomplete
  • only got immunity to clincal manifestations, NOT infection
  • adults in endemic areas have asymptomatic infections that do not cause disease
• endemic areas resistance to clinical disease comes very slowly with age
  • depends on level of exposure (develops quicker if transmission intensity is higher)

• duffy antigen on RBC's
  • needed for P. vivax to bind and invade RBC's
  • absent in West Africa populations
• sickle cell trait (heterozygous for abnormal gene)
  • protective against P. flaciparum

• lose resisitance to infection, especially in first trimester
  • after subsequent pregnancies, more resistant to infection (EXCEPT in HIV)
• pregnant women more susceptible to malaria
• leading cause of intrauterine growth retardation
• assoc. w/
  • anemia (mom, newborn)
  • prematurity
  • low birth weight
  • intrauterine growth retardation
  • infant mortality

• non immune adults (essentially, they are immunologically a child)
• can develop sever disease
  • resemble infants living in endemic areas in manifestation of infection
  • can see cerebral malaria with P falciparum
  • can result in rapid death

MEDICAL EMERGENCY

• microscopy of blood thin and thick smear
  • capillary blood best (fingerstick) (due to cytoadherence in small bv's)
  • thick smear allows us to better see the parasite
  • high sensitivity, specificity if done by experienced microscopy
  • can establish infecting species and level of infection
  • used to confirm cure after tx
• rapid diagnostic tests (RDT's)- easy to use, but expensive
  • detect parasite Ag in blood
  • immunochromatography
  • Binax now licensed by FDA

Serology has no place in dx of acute infection

• species
  • if ovale, vivax, must treat liver dormant cells to prevent relapze
• severity- complicated vs. uncomplicated
• area of travel- drug resistance

• if severe malaria, IV drugs
• choice of drug depends on endemic area because of spreading drug resistance
• supportive therapy- ICU, IV fluids, anticonvulsants if seizurs, glucose if hypoglycemic
• if high parasitemia, coma, renal failure, ARDS, we do exchange transfusion

• reduce exposure to mosquitos
  • insect repellent (DEET)
  • bednets insecticide treated
  • cover skin
• chemoprophylaxis with antimalarial
  • choice of drug mostly on itinerary
  • there are chloroquine sensitive and resistant areas

• increase drug resistance
• social political change
• environmental change
• HIV/AIDS
• insecticide resistance

• early dx and effective dx (combo therapy recommended by WHO)
• insecticide treated bednets (shown to reduce child mortality and reduce malaria in preg.)
• intermittent prevention tx in pregnancy
• intermittent prevention tx in infants
• vector control (indoor residual spraying)

• re treatment of bednest (every 6-12 mnths)
  • long lasting ITN's have now been developed
• uptake/use
• cost
• insecticide resistance

• drug given more than 2 times in pregnancy to protect against maternal anemia and low birth weight
  • less effective in HIV positive
• recommended in areas of medium to high stable transmission

• increased use of ACT's
• new antimalarial drugs
• new insecticides
• insecticide treated nets
• improved health deleivery systems
  • improved dectection, early tx
  • improve coverage with insecticide treated nets, preventative treatment
• development of malaria vaccines

• its an Apicomplexan parasite (intraRBC protozoa)
• most illness in humans due to Babesia microti

• epidemiology
  • tick born zoonosis (Ixodes scapularis- also causes Lyme disease)
  • requires more than 24 hrs of attachment
  • endemic in coastal southern New England, Wisconsi, Maine
  • reservoir- white footed mouse
  • transmission may occur through blood transfusion
  • cases mostly in summer

• asymp. in 25% (esp. in children)
• incubation: 1-6 weeks
• flu like symptoms- fever, chills, sweats, fatigue
• illness can last weeks to months

• ARDS
• massive hemolysis
• CHF
• renal failure
• death

elderly and asplenic at higher risk (no spleen leads to uncontrolled parasitemia)

• microscopic exam of blood
  • Giemsa stain
  • tetrads rare but pathognomonic
  • maltese cross
• rule out coinfection with Borrelia burgodorferi aka Lyme disease

• infection mostly self limited
• treat severe and symptomatic disease
• if HIV positive, need long term suppressive therapy
• exchange tranfusion if high parasitemia and severe disease