Malaria Babesia

Question 1

Explain why P. falciparum causes the most severe disease of
all Plasmodium species and how it can be diagnosed

Answer 1

• cause high % infected RBCs (parasitemia)
• infects all ages of RBCs
• causes cerebral malaria, black water fever, severe anemia

Question 2

WIP Describe the mechanism of pathogenicity for P. falciparum

Question 3

Identify a characteristic of P. vivax and P. ovale which
complicates chemotherapy

Question 4

Identify methods used to diagnose malaria infection

Question 5

Name a problem for the eradication of malaria worldwide

Question 6

Vector of Malaria

Answer 6

Anopheles game is

Question 7

Which area of apicomplexa insects into vector cells ?n

Answer 7

Polar ring
- imagine the sharp tip of an almond

Question 8

4 species of Plasmodium

Answer 8

1. P. Falciparum
2. P. Vivax
3. P. Ovale
4. P. Malariae

Question 9

3 stages of Malaria life cycle

Answer 9

1. Sporogonic (mosquito vector)
   - mosquito vector ingests gametocytes from blood
   - development of oocyst = release of sporozoites
2. Exo-erythrocytic cycle (human vector)
   - mosquito injects sporozoites into blood
   - infects LIVER cell
   - development of schizont = ruptures
3. Erythrocytic (human vector)
   - immature trophozoite (ring stage)
   a). Matures into another schizont = more trophozoites
   b). Forms gametocyte for another mosquito to ingest

Question 10

When is the best time to detect malaria ?

Answer 10

During a fever = collect patient blood
- corresponds to rupture of RBCs/ schizonts released

Question 11

Symptoms of malaria

Answer 11

• Fever (schizonts released from RBCs)
• Anemia (hemolysis)
• Splenomegaly (spleen removes infected RBCs)

Question 12

Which Plasmodium species have a higher risk of splenic rupture ?

Answer 12

• P. vivax
• P. ovale

Question 13

How is malaria detected in the lab ?

Answer 13

• Microscopic; thin and thick smears
• Rapid diagnostic tests; only detect antigens, so not reliant on good immune functioning

Question 14

What are hypnozoites ? Which species have them ?

Answer 14

P. Vivax and P. Ovale remain latent in liver

Question 15

Which Plasmodium species are benign ?

Answer 15

P. Malariae

Question 16

What is Cerebral malaria ?

Answer 16

• complications of P. Falciparum
• metabolic encephalopathy
• sequestration; P. Falciparum binds endothelium in cerebral
• cerebral anoxia associated with increased glucose catabolism/ lactate production by infected sticky RBC clumps

Question 17

What is Blackwater Fever ?

Answer 17

• complication of P. Falciparum
• hemoglobinuria secondary to massive hemolysis

Question 18

WIP How and why do parasites differentiate into gametocyte form ?

Answer 18

• other parasites “tell” other parasites when they should differentiate
• Ensure survival of species
• ## Extracellular vesicles (exosomes) formed by endocytosis of plasma membrane

Question 19

What causes anemia by Malaria ?

Answer 19

• lysis of RBC = increased splenic removal of rosetting RBCs
• release of TNF-a from immune cells = decreases EPO

Question 20

Which treatment is now used for Malaria ? Why ?

Answer 20

• Chloroquinine resistance called for new treatment
• Combination therapy now used (artemisinin based combination therapy — ACT)

Question 21

Why is vaccine development for Malaria difficult ?

Answer 21

Malaria has different stages to target (pre-erythrocytic stage has been most successful)

Question 22

Babesia structure

Answer 22

Apicomplexan

Question 23

Name the major species of babesiosis in the U.S

Answer 23

Ixodes scapularis; tick that cause lime disease

Question 24

Identify the vector for Babesia sp.

Answer 24

Ixodes scapularis; tick in lime disease

Question 25

Describe the pathogenesis

Answer 25

• nymphoid ticks inject sporozites into blood = attach to RBCs
• AMA1 attach to surface proteins
• develop into trophozoites = binary fission into 2-4 merozoites
• RBC release (hemolysis)

AMA1 = apical membrane antigen 1

Question 26

Name diagnostic methods used to identify the
infection

Answer 26

• Giemsa stained blood smear
• PCR
• Serology (blood Ab to Babesia); unreliable bc can be present after infection

Question 27

Understand the clinical significance of Babesia in
mixed infections, in elderly and in
immunocompromised