Malaria

1. See Also
   1. Malaria Chemoprohylaxis
   2. Vector-Borne Infection
   3. Prevention of Vector-borne Infection
2. Etiology
   1. Plasmodium vivax
   2. Plasmodium ovale
   3. Plasmodium falciparum
   4. Plasmodium malariae
3. Pathophysiology
   1. See Vector-Borne Infection
   2. Transmitted by bite of anopheline Mosquito
      1. Usually bites between dusk and dawn
      2. Injects Malaria protozoa from Salivary Glands
   3. Species of Malaria
      1. Plasmodium falciparum
      2. Plasmodium vivax
      3. Plasmodium malariae
      4. Plasmodium ovale
   4. Life cycle of Malaria
      1. Injected from Mosquito as sporozoite
      2. Sporozoites invade hepatocytes
      3. Released into blood stream as merozoites
      4. Merozoites invade erythrocytes and circulate freely
      5. Sporozoites may lie dormant in liver (hypnozoites)
         1. Occurs with Plasmodium vivax and Plasmodium ovale
         2. Symptoms recur when reactivates in months to years
      6. Circulating merozoites differentiate into Gametocytes
         1. Gametocytes are the sexual form of plasmodium
         2. Mosquito ingests gametocytes from infected host
         3. Mosquito infects next human host with bite
4. Epidemiology
   1. Incidence
      1. Most common life threatening disease for travelers
      2. European, North American traveler cases: 30,000/year
      3. Cases reported to CDC per year: 1500
      4. Worldwide Infections: 300 million per year
      5. Worldwide Mortality: 1-3 million deaths per year
   2. Regions
      1. Endemic to tropical and subtropical world
      2. Highest Risk
         1. Sub-Saharan Africa
         2. Papua New Guinea
         3. Solomon Islands
         4. Vanuatu
      3. Intermediate Risk
         1. Haiti
         2. Indian subcontinent
      4. Low Risk
         1. Southeast Asia
         2. Latin America
5. Symptoms
   1. Initial prodrome
      1. Headache
      2. Malaise
   2. Soon later
      1. Fever
      2. Shaking chills
   3. Soon later
      1. Drowsiness
      2. Lethargy
6. Signs
   1. Fever for 1-8 hours
   2. Fever recurs
      1. Plasmodium vivax: 48 hours
      2. Plasmodium malariae: 72 hours
      3. Plasmodium falciparum: Variable
   3. Tender Splenomegaly
7. Labs
   1. Complete Blood Count (CBC)
      1. Hemoglobin or Hematocrit consistent with Anemia
   2. Urinalysis
      1. Urobilinogen positive
8. Diagnosis
   1. Peripheral blood smear with Giemsa or Wright stain
      1. Gold standard for diagnosis
      2. Examine new smear every 12-24 hours for 3 days
      3. Sample is best obtained when patient is febrile
      4. Image
         1. 
   2. Rapid blood dipstick testing (when smear not available)
      1. HRP-2 detection (only detects P. falciparum)
      2. LDH detection (detects all 4 Malaria types)
9. Management
   1. Chemoprophylaxis
      1. See Malaria Chemoprophylaxis
   2. Treatment (see specific medications for dosing)
      1. Mefloquine
      2. Pyrimethamine with sulfadoxine (Fansidar)
      3. Primaquine
10. Prevention
    1. See Prevention of Vector-borne Infection
    2. Stay in air conditioned or well screened rooms
    3. Reduce nighttime outdoor activity (Dusk until dawn)
    4. Apply DEET (30%) to skin every 3-4 hours
    5. Spray clothing and bed nets with Permethrin
    6. Wear long sleeve shirt and pants
    7. Use insecticide aerosols at dusk in living areas
    8. Use a strong fan at bedside
    9. Use Mosquito bed netting even in hotel rooms
       1. Mosquito net pre-treated with Permethrin
       2. Reapply Permethrin every 6 months
11. Prognosis
    1. Plasmodium falciparum Mortality: 4% (20% severe cases)
12. Resources
    1. See Travel Resources
    2. Malaria Foundation International
       1. http://www.malaria.org
    3. CDC Malaria hotline
       1. Phone: 770-488-7788
13. References
    1. Baird (1999) Med Clin North Am 83(4):923-44
    2. Croft (2000) BMJ 321(7254):154-60
    3. Lo Re (2003) Am Fam Physician 68(3):509-16