Dr. Libman -- Parasitology 2: Malaria Flashcards Preview

Block G -- Infection > Dr. Libman -- Parasitology 2: Malaria > Flashcards

Flashcards in Dr. Libman -- Parasitology 2: Malaria Deck (49)
1

Describe the epidemiology of malaria

  • 500 million febrile episdoes per year
  • Millions of deaths per year
  • Extremely widespread until 20th C
  • Exceptions include Sub-saharan africa (resurgent disease since 1980's - 1990's)

2

3 causes of sub-saharan africa having resurgent malaria since 1980-1990's

  1. Emergent drug resistance
  2. Few affordable alternatives
  3. Failed mosquito control

3

Organism responsible for malaria

Plasmodium spp. protozoan

4

Malaria vector

Anopheles mosquito

5

Only reservoir of malaria

Humans

6

Describe the distribution of malaria (5 locations)

  • Central America
  • Tropical South America
  • Sub-Saharan Africa
  • South Asia
  • South-east Asia

7

6 organisms that are a part of phylum apicomplexa

  1. Plasmodium spp.
  2. Toxoplasma gondii
  3. Cryptosoporium parvum
  4. Isospora belli
  5. Cyclospora cayatenensis
  6. Babesia microti

8

5 organisms belonging to Plasmodium spp.

  1. Plasmodium falciparum
  2. Plasmodium vivax
  3. Plasmodium ovale
  4. Plasmodium malariae
  5. Plasmodium knowlesi

9

Compare P. knowlesi to its familial counterparts

  • Same morphology as P. malariae
  • High parasitemia and mortlaity like P. falciparum

10

Give a general overview of the lifecycle of malaria (9 steps and 1 aside)

  1. Human has malaria
  2. Mosquito takes blood
  3. Mosquito bites someone else --> malaria in that person
  4. Rapid intake to liver (developmental phase)
  5. Enter blood
  6. Invade RBCs
  7. Mulitplication of organism
  8. Red cell rupture
  9. More red cells infected

NOTE: a few become gametocytes instead --> mosquito eats --> mate in mosquito to become another malaria infection to be transmitted

11

Protozoa that is NOT a zoonosis

Entamoeba histolytica

12

What is a sporozoite

Form of malaria transmitted by the mosquito, which enters the liver

13

What is a schizont?

Form of malaria that infects the red blood cells to multiply after having developed in the liver

14

RBC receptor for P. vivax

Duffy/Antigen

15

Area of the world that is Duffy AG negative and what this means

West Africa = immune to vivax (but has evolved to become a different type of plasmodium)

16

11 symptoms of malaria

  1. Chills
  2. Rigors
  3. Fever
  4. Perspiration
  5. Fatigue
  6. Headache
  7. Delirium
  8. Confusion
  9. Coma
  10. Shortness of breath
  11. Jaundice

17

2 signs of malaria

  1. Anemia
  2. Splenomegaly

18

Describe the fever pattern of malaria

  • Vivax = tertiant (every second day)
  • Malariae = Quartent (every third day)
  • Falciparum = Quotidian (daily spikes of fever that persist for a few days and occasionally break every couple of days)

19

How does a fever pattern occur with malaria?

Synchronized parasites

20

What is the cause of a fever coming back from the tropics?

Malaria until proven otherwise

21

7 reasons for death due to malaria, starting with the most common cause

  1. Cerebral malaria (50%)
  2. ARDS (46%)
  3. Renal failure (40%)
  4. Hematological (13%)
  5. Shock (10%)
  6. Sepsis (5%)
  7. Ruptured spleen (5%)

22

Reason for sepsis due to malaria

Leaky blood vessels and ischemia in the gut

23

General timeline of fatality from onset of symptoms (fever) in malaria

A week

24

What is black water fever?

Malaria with hemolysis producing blackened urine (quinine can aggravate)

25

Why must you not underestimate the results of venous blood samples when testing for malaria?

Deformed red cells express malaria antigen and get sequestered into small blood vessels (microcirculation) so cannot detect in blood sample

26

Pathophysiology of cerebral malaria (4 points)

  1. Sticky RBC knobs
  2. High TNF levels
  3. Poor deformability of infected RBCs
  4. Increased endothelial permiability

27

2 effects of high TNF levels in cerebral malaria

  1. Vascular endothelial adhesiveness
  2. Direct CNS effects

28

3 types of modulators of clinical severity of ARDS in malaria

  1. Transmission intensity
  2. Co-infections
  3. Host polymorphisms

29

What does an EBV co-infection in infancy lead to?

Burkitt's lymphoma

30

Effect of hemoglobinopathy on risk of malaria infection

Decrease

31

What is a reliable indicator of malaria in a regoin where malaria is not apparent in adults?

Measurement of kids' spleen sizes

32

Why might a region seem unaffected by malaria?

Adults have developed a partial immunity to malaria due to constant re-infection, so symptoms may be very minimal despite high transmission rates

33

2 types of north american mosquitoes that can act as a vector of malaria

  1. Anopheles freeborni
  2. Anopheles quadrimaculatus

34

How was malaria diagnosied in 1849

Fever chart

35

6 lab findings of malaria

  1. CBC
    • Thrombocytopenia
    • Leukopenia
  2. LFT = high liver enzymes
  3. Prothrombin time = increased
  4. Glucose = decreased
  5. Serum K+ = increased
  6. Creatinine = increased

36

Antimalarial treatment in a chloroquine sensitive area

Chloroquine phosphate 250 mg tabs:

  1. 1,000 mg STAT
  2. 500 mg 6 hours later
  3. 500 mg daily for 2 days

37

Antimalarial prophylaxis in chloroquin sensitive area (2)

  • Chloroquine
  • Daraprim
  • + all chloroquine resistant regions' drugs

38

Antimalarial treatment in chloroquine resistant area (5)

  1. Quinine + tetracycline OR clindamycin OR Fansidar (sulfadoxine and pyrimathamine)
  2. Artesunate combination therapy
  3. Doxycycline
  4. Malarone (atovaquone/proguanil)
  5. Mefloquine (a quinoline methanol)

39

6 antimalarial prophylaxis in chloroquine resistant area

  1. Mefloquine (250 mg weekly)
  2. Atovaquone/proguanil (Malarone) daily
  3. Doxycycline 100 mg daily
  4. Primaquine 30 mg base daily
  5. Chloroquine 500 mg weekly and paludrine 200 mg daily
  6. Permethrin treated bednet nightly

40

3 ways drugs used for malaria prophylaxis can work

  1. Kill parasites in liver (causal prophylaxis)
  2. Kill asexual parasites in RBCs (suppressive prophylaxis)
  3. Kill sexual parasites (gametocytes) in RBCs (gametocytocidal prophylaxis)

41

Chloroquine sensitive areas (5)

  1. Central America
  2. Argentina
  3. Most of the Middle East
  4. Southeast China
  5. Dominican Republic/Haiti

42

Reason for using combination therapy in chloroquine resistant malaria

  • Drug 1 brings down malaria quickly, but is poor at eradicating it
  • Drug 2 acts more slowly, but eradicates malaria from the body

43

Mefloquine and chloroquine resistant regions

  • Northwest Thailand (bordering Myanmar)
  • Northwest Cambodia and around Thailand border

44

When to use exchange transfusion as a treatment of severe malaria (2 cases with 6 sub-points)

  1. 10% + parasitemia
  2. 5% + parasitemia
    • With complications of shock
    • Abnormal levels of consciousness
    • Pulmonary edema
    • Renal failure
    • Cardiac dysfunction
    • High volume diarrhea or vomiting

45

3 types of measures to prevent malaria

  1. Mosquito avoidance
  2. Mosquito killing
  3. Plasmodium killling

46

6 ways to avoid mosquitoes

  • Understand evening and night behavior
  • Mosquito nets
  • Air conditioning
  • Screens
  • Mosquito repellents
  • Pyrethrum coils

47

3 ways to kill mosquitoes

  • Destroy breeding sites
  • Fog spraying
  • Residual spraying

48

48 hour cycle of the life of a mosquito (6)

  1. Adult bites at night
  2. Adult female rests (on inside wall)
  3. Lay eggs (water surface)
  4. Larva (wter surface)
  5. Pupa (water surface
  6. Adult searches for blood meal

49

3 antimalarials that are derived from plants

  • Artesunate
  • Pyrethroids
  • Quinine