Micro: Blood parasites

Question 1

Vector for all Malaria parasites.

Answer 1

Anopheles mosquito

Question 2

Describe the steps (5-ish) in the malaria life cycle.

Answer 2

1. Infected mosquito bites host
2. Sporozoite form migrates to the liver and replicate
3. Merozoite form migrates from the liver and infects RBCs and replicates forming gametocytes (falciparum only)
4. Lysis of RBCs causes symptoms and releases new parasites into the blood
5. New parasites can spread to mosquitos that bite the host

Question 3

Why does Plasmodium vivax cause a relapsing malaria infection?

Answer 3

Forms a unique stage in its lifecycle called Hypnozoites. This stage can remain dormant in the liver for months to years and is resistant to standard anti-malaria meds.

Question 4

What is hemozoin?

Answer 4

Toxic metabolite of heme degradation formed with enzymes from blood parasites. Normally it is detoxified by the parasite and used for protein synthesis, however, when the RBC is lysed by the parasite some of the hemozoin is released in the circulation without being detoxified.

It is then phagocytosed by host WBCs altering blood cell and platelet formation (leading to low WBC and platelet counts) and causing production of ROS which damage RBCs (leading to hemolysis and symptoms).

Question 5

Characteristic of RBCs viewed on blood smear indicating P. vivax infection.

Answer 5

Schuffner dots

Question 6

Charactertic of RBCs viewed on blood smear indicating P falciparum infection

Answer 6

Boomerang gametocyte (or sausage or banana)

Question 7

Genetic disease most commonly associated with malaria resistance.

Answer 7

Sickle Cell Disease or Trait

Question 8

DOC for non-severe malaria or areas with resistance.

Answer 8

Chloroquine

Question 9

DOC for severe malaria cases.

Answer 9

Quinine/Quinidine

can cause renal or ototoxicity

Question 10

DOC for P. vivax infection.

Answer 10

Chloroquine + Primaquine

primaquine works on the hypnozoite form in the liver to prevent relapse

Question 11

Anti-malarial MOA of quinolones. (chloroquine, quinine, mefloquine)

Answer 11

Inhibit Heme polymerase preventing metabolism of heme to hemozoin

Question 12

2 most common side effects of chloroquine.

Answer 12

1. Pruritis

2. Retinopathy

Question 13

Primary indication for mefloquine.

Answer 13

Malaria prophylaxis

Question 14

Major side effect of mefloquine.

Answer 14

Psychiatric disorders from prolonged use

Question 15

MOA of Primaquine.

Answer 15

Inhibits electron transport chain in P. vivax.

Question 16

2 contraindications for using Primaquine.

Answer 16

Glucose-6-phosphate dehydrogenase deficiency patients and pregnant patients.

Will cause hemolytic anemia.

Question 17

Main toxicity of folic acid antagonists.

Answer 17

Bone marrow depression

Question 18

MOA of doxycycline as an anti-malaria agent.

Answer 18

Prevents apicoplast function (some thing found in the parasite)

This drug is mainly used as a prophylaxis.

Question 19

What is the contraindication for doxycycline use?

Answer 19

Not in children younger than 8 or pregnant women as it can lead to bone and teeth malformation

Question 20

What is Malarone?

Answer 20

Anti-malarial combination of Atovaquone (electron transport inhibitor) and Proguanil (antifolate). Mainly used for prophylaxis

Question 21

MOA of the Sesquiterpenes: artemether and artesunate.

Answer 21

Bind to the iron in heme to prevent metabolism to hemozoin.

Question 22

Babesosis is often a co-infection with what other disease?

Answer 22

Lyme Disease

Question 23

What are symptoms of Babesiosis?

Answer 23

Similar to malaria; nausea, night sweats, weight loss, hematuria, ARDS

Question 24

What is the vector and reservoir for B. microti?

Answer 24

Black legged ticks are the vector. White-footed mice are the reservoir.

(humans can be a reservoir but unlike malaria where mosquitos can bite an infected human and become a vector for malaria to be transmitted to other humans, ticks rarely bite an infected human and then transmit to another human. The normally bite an infected mouse and then bite a human.)

Question 25

Main blood smear characteristic indicative of B microti infection.

Answer 25

Maltese cross

also has a ring form

Question 26

What is the treatment for Babesiosis?

Answer 26

Usually treated for Lyme Disease first with doxycycline or amoxicillin.

Then a combination is needed for babesiosis.
-clindamycin plus quinine
or
-atovaquone plus azithromycin

Question 27

Microbe and vector that causes African Sleeping Sickness.

Answer 27

Trypanosoma brucei

Vector: Tsetse fly

Question 28

Symptoms of African sleeping sickness.

Answer 28

Pruritis at the fly bite site along with fever and lymphadenopathy.

If the parasite reaches the brain the patient is tired during the day and restless at night.

Question 29

Microbe and vector that causes Chagas Disease.

Answer 29

Trrpanosoma cruzi

Vector: Reduviid bug

Question 30

Term given to the form of T. cruzi when it is in the tissue that causes the immune response in the host.

Answer 30

Amastigote form

Question 31

What symptom occurs in acute stages unique to T. cruzi infection?

Answer 31

Romana sign

unilateral periorbital edema

Question 32

Most serious and lethal symptom of chronic chagas disease.

Answer 32

Myocarditis (T cruzi is #1 cause in the world)

Question 33

Bug and vector that causes mucocutaneous Leishmaniasis.

Answer 33

Leishmania braailiensis

Vector: sandflies

Question 34

Bug and vector that causes visceral Leishmaniasis.

Answer 34

Leishmania donovani

Vector: sandflies

Question 35

Name two filarial worms that can cause retinopathy.

Answer 35

Onchocerca volvulus

Loa loa

Question 36

Microbe responsible for elephantiasis

Answer 36

AKA Lymphatic filariasis

Wuchereria bancrofti

Question 37

1 cause of bladder cancer worldwide.

Answer 37

Schistosoma haematobium

Question 38

How can S. haematobium and mansoni be diagnosed?

Answer 38

Symptoms and viewing eggs on microscopy.
haematobium: hematuria, terminal spine eggs in urine

mansoni: bloody diarrhea, lateral spine eggs in feces