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Flashcards in Microbes of the blood Deck (24)
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1

Malarial diseases

- Plasmodium Falciparum
- Vivax
- Malariae
- Ovale
- Knowlesi

2

What is the primary malarial vector?

- Anolpheles

3

Describe the malaria life cycle

- 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

4

What is a histological finding unique to Ovale and vivax?

- Schuffner's dots

5

How long after inoculation before patient presents with symptoms?

- 2-5 weeks

6

What malarial strain produces severe malaria and why?

- 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.

7

How does rosetting in P. Falciparum contribute to disease?

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

8

What is the diagnostic approach for malaria?

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

9

What diseases protect against malarial infection?

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

10

How does sickle cell protect against malaria?

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

11

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

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

12

What is the transmission and epidemiology of Babesiosis Microti?

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

13

What is commonly co-infected with Babesiosis?

- Borrelia Burgdorferi, Ehrlichia and Anaplasma

14

How is Babesiosis identified on blood smear?

- Maltese cross ring troph
- Rings appear oval with no hemozoin

15

What are the symptoms of Babesiosis?

- Fever, chills, flu like illness
- Hemolysis and anemia

16

What is the classification of Ehrlichia and Anaplasma?

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

17

What cells do Ehrlichia infect?

- Monocytes

18

What cells do Anaplasmosis infect?

- Granulocytes

19

How are Erlichia and Anaplasma identified?

- Intracellular morula

20

What tick transmits Anaplama?

- Ixodes tick
- Peromyscus leucopus

21

What tick transmits Ehrlichia?

- Ambloyomma americanum (the lone star tick)
- Deer

22

How are Ehrlichiosis and Anaplasmosis treated?

- Doxycycline

23

How do patients with Ehrlichiosis and Anaplasmosis present?

- Fever, chills, HA, mialgia, malaise

24

Who commonly presents with Ehrlichiosis and Anaplasmosis?

- Elderly in the north east
- Common co-infection with Borrelia, and babesiosis (anaplasmosis)