Microbes of the blood

Question 1

Malarial diseases

Answer 1

• Plasmodium Falciparum
• Vivax
• Malariae
• Ovale
• Knowlesi

Question 2

What is the primary malarial vector?

Answer 2

• Anolpheles

Question 3

Describe the malaria life cycle

Answer 3

• Mosquito inoculates sporozoites into blood steam
• Invade liver cells and undergo single round of schizogony (7-14 days) releasing merozoites to blood stream
• Merozoites invade RBC and undergo multiple rounds of schizogony (2-3 days)
• Some develop into gametocytes which can then be taken up by mosquitos
• Ovale and Vivax–> hypnozoites in the liver–> relapse

Question 4

What is a histological finding unique to Ovale and vivax?

Answer 4

• Schuffner’s dots

Question 5

How long after inoculation before patient presents with symptoms?

Answer 5

• 2-5 weeks

Question 6

What malarial strain produces severe malaria and why?

Answer 6

• P. falciparum
• 20-30% BC infection
• PfEMP1 and other proteins produced on the surface of the RBC cause clumping and rosetting which allows for immune evasion from spleen.

Question 7

How does rosetting in P. Falciparum contribute to disease?

Answer 7

• Stasis and hypoxia
• Increased cytokine production and cerebral endothelium receptor expression increasing sequestration
• NO and TNF interferes with neuronal signaling

Question 8

What is the diagnostic approach for malaria?

Answer 8

• Microscopy - Thick and thin smears
• Serologic - antibody
• PCR - specific species
• Rapid diagnostics - HRP-2 –> P.F., LDH –> P. F or Vivax

Question 9

What diseases protect against malarial infection?

Answer 9

• Sickle cell
• Duffy blood groups
• Thalassemia
• G6PD deficiency

Question 10

How does sickle cell protect against malaria?

Answer 10

• Resistance to P. Falciparum
• Low O2
• PfEMP1 malformation
• Micro RNA’s inhibit parasite growth
• Heme oxygenase- 1–> antioxidants which inhibit cerebral malaria

Question 11

How does Duffy blood group confer resistance and to which strains?

Answer 11

• P. vivax and knowlesi
• Duffy negative - lack non-specific cytokine glycosylated protein that parasite uses for infection.
• Common in Africans

Question 12

What is the transmission and epidemiology of Babesiosis Microti?

Answer 12

• By Ixodes tick vector
• Blood transfusions
• Summer months
• Symptoms seen in elderly, asplenic or immunocompromised in the north east and upper midwest

Question 13

What is commonly co-infected with Babesiosis?

Answer 13

• Borrelia Burgdorferi, Ehrlichia and Anaplasma

Question 14

How is Babesiosis identified on blood smear?

Answer 14

• Maltese cross ring troph

- Rings appear oval with no hemozoin

Question 15

What are the symptoms of Babesiosis?

Answer 15

• Fever, chills, flu like illness

- Hemolysis and anemia

Question 16

What is the classification of Ehrlichia and Anaplasma?

Answer 16

• Gram negative, intracellular bacteria related to the rickettsia
• Tick borne illness

Question 17

What cells do Ehrlichia infect?

Answer 17

• Monocytes

Question 18

What cells do Anaplasmosis infect?

Answer 18

• Granulocytes

Question 19

How are Erlichia and Anaplasma identified?

Answer 19

• Intracellular morula

Question 20

What tick transmits Anaplama?

Answer 20

• Ixodes tick

- Peromyscus leucopus

Question 21

What tick transmits Ehrlichia?

Answer 21

• Ambloyomma americanum (the lone star tick)

- Deer

Question 22

How are Ehrlichiosis and Anaplasmosis treated?

Answer 22

• Doxycycline

Question 23

How do patients with Ehrlichiosis and Anaplasmosis present?

Answer 23

• Fever, chills, HA, mialgia, malaise

Question 24

Who commonly presents with Ehrlichiosis and Anaplasmosis?

Answer 24

• Elderly in the north east

- Common co-infection with Borrelia, and babesiosis (anaplasmosis)