Malaria And Babesiosis

Front 1

Malaria is caused by members of the genus ____

Back 1

Plasmodium

Front 2

The Plasmodium spp. belong to Phylum ____

Back 2

Apicomplexa

Front 3

The Plasmodium spp. are (metozoa or protozoa?)

Back 3

Protozoa

Front 4

What is the definitive host of the Plasmodium spp.?

Back 4

Female Anopheles mosquitos

Front 5

How many people are infected with malaria each year? How many die?

Back 5

300,000,000

1-2 million deaths

Front 6

Where do 90% of malaria-related deaths occur?

Back 6

Sub-saharan Africa

Front 7

Where is malaria endemic?

Back 7

Tropical and temperate regions of the world

Front 8

How do US citizens acquire malaria?

Back 8

Travel to endemic areas

Front 9

How many vertebrate hosts does each Plasmodium spp. have?

Back 9

One (human, mouse, etc.)

Front 10

Which Plasmodium spp. cause malaria in humans?

Back 10

P. falciparum

P. vivax

P. ovale

P. malariae

Front 11

Why is malaria only transmitted by female Anopheles mosquitos?

Back 11

Male Anopheles mosquitos feed on nectar, not blood

Front 12

Why must female Anopheles mosquitos feed on blood?

Back 12

Nourishment of eggs

Front 13

How many times will a female Anopheles mosquito lay eggs in its lifetime?

Back 13

4-5 clutches, each requiring a bloodmeal

Front 14

Where do female Anopheles mosquitos lay their eggs?

Back 14

Stagnant water (discarded tires, puddles, ponds)

Front 15

Describe the malaria life cycle

Back 15

1) Mosquito bite releases sporozoites into the bloodstream

2) Sporozoites invade hepatocytes and undergo several cycles of replication

3) Merozoites are released into the bloodstream, where they invade RBCs

4) Once inside RBCs, merozoites develop from the "ring stage" to the trophozoite stage

5) Trophozoites undergo schizogency, resulting in the release of merozoites that attack fresh RBCs

6) Some merozoites become gametes, which remain in RBCs and are taken up by mosquitos during a bloodmeal

7) In the mosquito, the male gamete exflagellates and fertilizes the female gamete, forming the ookinete

8) Ookinetes traverse the midgut wall and develop into oocysts

8) After 10-14 days of maturation, oocysts release sporozoites into the hemolymph

9) Sporozoites travel to the salivary gland to infect the next host during a subsequent bloodmeal

Front 16

Which stage of Plasmodia asexual reproduction (exraerythrocytic or erythrocytic) is symptomatic in humans?

Back 16

Erythrocytic

Front 17

What is the classical method for detecting the erythrocytic stages of malaria?

Back 17

Blood smear

Front 18

What kind of stain is used for a malaria blood smear?

Back 18

Giemsa stain

Front 19

Detection of erythrocytic stages of malaria in the blood is indicative of (active or inactive?) infection

Back 19

Active

Front 20

Appropriate treatment of malaria requires...

Back 20

1) Identification of the species causing the infection (co-infections are possible)

2) Patient history (travel to endemic regions)

3) Knowledge of the drug sensitivity/resistance profile

Front 21

The pre-patent period of a malarial infection is the time between...

Back 21

Time of infection (bite of an infected mosquito) to when the erythrocytic cycle commences

Front 22

What is the basic symptom of erythrocytic malaria?

Back 22

High fever (40-41°C) with a defined periodicity

Front 23

Tertian malaria (Definition)

Back 23

Malaria characterized by a fever with 48 hour periodicity (fever on days 1, 3, 5, etc.)

Front 24

Quartran malaria (Definition)

Back 24

Malaria characterized by a fever with 72 hour periodicity (fever on days 1, 4, 7, etc.)

Front 25

What is the relationship between the number of merozoites released from the liver and severity of disease?

Back 25

The higher the number of merozoites, the more severe the disease

Front 26

Number of merozoites released per hepatocytes for each of the four Plasmodium spp.

Back 26

P. falciparum: 40,000/cell (5-7 days)

P. vivax: 10,000/cell (6-8 days)

P. ovale: 15,000/cell (9 days)

P. malariae: 2,000/cell (2 weeks)

Front 27

What are the steps involved in the erythrocytic cycle of malaria?

Back 27

1) Invasion of the RBC

2) Ring stage

3) Early trophozoite

4) Mature trophozoite (accumulation of Malaria Pigment in the food vacuole)

5) Schizogeny (early shizont, schizont, mature schizont, release of merozoites)

Front 28

From where within RBCs do malarial trophozoites derive the bulk of nutrients required for growth?

Back 28

Hemoglobin

Front 29

How do malarial trophozoites degrade hemoglobin?

Back 29

Endocytosis into the parasite food vacuole

Front 30

What is the toxic end-product of hemoglobin degradation by malaria trophozoites?

Back 30

Heme

Front 31

How do malarial trophozoites detoxify free heme?

Back 31

Polymerization of heme into hemozoin (Malarial Pigment)

Front 32

Besides the degradation of hemoglobin, how else do Plasmodia modify erythrocytes?

Back 32

Membranous projections into the cytosol (Maurer's clefts, tubular vesicular network or TVN)

Surface projections called "knobs"

Front 33

What is the function of the knobs on the surface of infected erythrocytes?

Back 33

They provide erythrocytes with adhesive properties to bind endothelial cells and other RBCs (rosetting)

Front 34

Which Plasmodium spp. is responsible for the vast majority of deaths due to malaria?

Back 34

Plasmodium falciparum

Front 35

What is the geographic distribution of P. falciparum?

Back 35

Africa

South Asia

South east Asia

Brazil

Front 36

F. falciparum causes what type of malaria?

Back 36

Severe malaria, Malaria Tropica, malignant tertian malaria

Front 37

Incubation, pre-patent, and patent periods of P. falciparum

Back 37

Incubation: 8-24 days

Pre-patent: 4-12 days

Patent: 4-6 weeks if treated, 18 months if untreated

Front 38

Relapses of P. falciparum are due mainly to organisms in the (extraerythrocytic or erythrocytic) stage

Back 38

Erythrocytic

Front 39

P. falciparum is a (tertian or quartran) malaria

Back 39

Tertian, but it does not always follow this periodicity

Front 40

Symptoms of P. falciparum malaria

Back 40

High fever that may follow a tertian pattern but may also be continuous

A phase of headache and general abdominal symptoms

Front 41

P. falciparum malaria may progress to...

Back 41

Cerebral malaria

Front 42

Why is it important to begin treatment for cerebral malaria immediately after the onset of symptoms?

Back 42

Coma and death can occur within 24 hours of the onset of symptoms

Front 43

How is P. falciparum malaria diagnosed?

Back 43

Blood smear

Front 44

Which erythrocytes are infected by P. falciparum?

Back 44

Mature erythrocytes

Front 45

What is the typical parasite burden (parasitemia) in P. falciparum malaria?

Back 45

50-500,000 parasites/mL blood

Can be as high as 2.5 million/mL

Front 46

Why is the parasite burden (parasitemia) in P. falciparum malaria so high?

Back 46

P. falciparum infects mature erythrocytes, which is the most abundant group

Front 47

How does P. falciparum cause cerebral malaria?

Back 47

Infected RBCs have adhesive knobs that make them stick to the endothelial lining of blood vessels, which limits blood flow to the brain

Front 48

Which knob protein is responsible for the adhesion of RBCs in P. falciparum malaria?

Back 48

P. falciparum Erythrocyte Membrane Protein 1 (PfEMP-1) a.k.a the Var family

Front 49

How does P. falciparum avoid immune detection?

Back 49

Var proteins exhibit antigenic variation

Front 50

How might P. falciparum affect pregnancy?

Back 50

Adhesive IE (infected erythrocytes) may block placental circulation to the fetus, leading to fetal anoxia, fetal and placental edema, and abortion after the first trimester

Often premature delivery, low birth weight, and anemia in the fetus

Front 51

Does P. falciparum cross the placental barrier?

Back 51

No

Front 52

When is the risk for P. falciparum-related complications during pregnancy the greatest?

Back 52

First pregnancy (and reduces with subsequent pregnancies)

Front 53

How might P. falciparum infection affect the kidneys?

Back 53

Adhesive IE (infected erythrocytes) may occlude the renal tubules, resulting in dark-colored urine, hemoglobinuria, acute renal failure, and mortality (20-30% of cases)

Front 54

What is the name for the renal complications that rarely accompany P. falciparum infection?

Back 54

Blackwater fever

Front 55

What is the most commonly encountered form of malaria?

Back 55

Malaria caused by Plasmodium vivax

Front 56

P. vivax causes what type of malaria?

Back 56

Malaria tertiana, benign tertian malaria

Front 57

Geographic distribution of P. vivax

Back 57

South and south east Asia

Africa

The New World (was endemic in parts of the US, including KY, in the 19th century)

Front 58

Is P. vivax usually fatal?

Back 58

No

Front 59

Describe the fever pattern of P. vivax malaria

Back 59

Highly regular tertian pattern preceded by several hours of intense shivering

Front 60

Incubation, pre-patent, and patent periods of P. vivax

Back 60

Incubation: 12-18 dyas

Pre-patent: 8-17 days

Patent: 5-7 years

Front 61

P. vivax has (high or low?) potential for reactivation. Why?

Back 61

High

Long patent period

Front 62

Reactivation of P. vivax malaria is due mainly to (RBC or liver?) stages of the parasite

Back 62

Liver (hypnozoites)

Front 63

What is the typical parasite burden (parasitemia) in P. vivax malaria?

Back 63

20,000 parsites/mL of blood

Maximum of ~50,000/mL

Front 64

Why is the parasite burden (parasitemia) of P. vivax so much lower than that of P. falciparum?

Back 64

P. vivax preferentially infects young (reticulo-endothelial) erythrocytes, which are fewer in the number than the mature erythrocytes infected by P. falciparum

Front 65

What are some distinctive features of P. vivax erythrocytes?

Back 65

Enlarged erythrocyte

Schuffner's dots

Mature-ring form appears coarse

Front 66

What is the rarest form of malaria?

Back 66

Malaria caused by P. ovale

Front 67

What type of malaria is caused by P. ovale?

Back 67

Malria tertiana (same as P. vivax)

Front 68

What is the mildest form of malaria?

Back 68

Malaria quartana, caused by Plasmodium malariae

Front 69

Describe the characteristic fever caused by P. malariae infection

Back 69

Quartan pattern

Preceded by intense shivers

Front 70

P. malariae preferentially infects ____ erythrocytes

Back 70

Old

Front 71

P. malariae has an extremely (long or short?) patent period

Back 71

Long (up to 30 years)

Front 72

Quartan malaria is often seen in what group of US patients?

Back 72

Vietnam vets

Front 73

What challenges complicate malaria treatment/prevention?

Back 73

Increasing drug resistance (including multiple drug resistance)

Antigenic variation of Var and other immunogenic proteins complicate vaccine development

Vector control (mosquito resistance, environmental concerns)

Political and socioeconomic issues (poverty, civil war/political instability)

Front 74

What genetic disease co-maps with malaria? Why?

Back 74

Sickle cell trait (heterozygotes)

Plasmodia cannot grow in sickle cell RBCs, which greatly reduces the severity of malaria

Front 75

The Babesia spp. belong to Phylum ____

Back 75

Apicomplexa

Front 76

What is the definitive host/vector of the Babesia spp.?

Back 76

Ixodes spp. ticks (same vector as Lyme disease)

Front 77

What is the intermediate host of the Babesia spp.?

Back 77

Mammals, including humans

Front 78

Where do Babesia replicate within humans?

Back 78

Within erythroctes

Front 79

Do Babesia have a liver stage in humans?

Back 79

No

Front 80

How do Babesia reproduce in humans?

Back 80

Binary fission

Front 81

Do Babesia degrade hemoglobin and produce hemozin?

Back 81

No

Front 82

Most Babesia infections in the US are caused by what species?

Back 82

Babesia microti

Front 83

Most Babesia infections are (symptomatic or asymptomatic?)

Back 83

Asymptomatic

Front 84

When are symptoms typically seen with Babesia infection?

Back 84

Heavy infections

Infection of the immunocompromised

Infections in the aged (weaker immune response)

Front 85

Babesia infection is typically fatal in ____ individuals

Back 85

Splenomectomised

Front 86

When are Babesia infections most commonly seen? Why?

Back 86

Between May and September

Coincides with tick biting behavior

Front 87

Main symptoms of babesiosis

Back 87

Continuous fever

Malaise

Abdominal symptoms

Flu-like symptoms

Front 88

Incubation period, pre-patent period, and patent period of Babesia microti

Back 88

Incubation: 1-4 weeks

Pre-patent: 1 week

Patent: 1 year

Front 89

How is babesiosis diagnosed?

Back 89

Giemsa stain of blood smear