Parasitology - Malaria

Front 1

T/F: the parasites that cause malaria are all intracellular protozoa

Back 1

True.

Front 2

Definitive host of Plasmodium

Back 2

Anopheles mosquito

Front 3

Life cycle of malaria parasites

Back 3

Mosquito injects SPOROZOITES into human --> sporozoites enter liver parenchyma and become MEROZOITES --> merozoites are released into circulation and infect red blood cells --> replication of merozoites within rbc's: RING STAGE --> cytoplasm synthesis --> nuclear replication --> cytoplasm division --> rbc lyses and releases metrozoites --> metrozoites differentiate into GAMETOCYTES --> gametocyte is taken up by mosquito --> gametocyte becomes GAMETES in the mosquito --> male (flagellated) and female gametes form zygote which produces SPOROZOITES that migrate to salivary gland

Front 4

Origin, target and progeny of sporozoite

Back 4

Comes from mosquito, infects liver cells, and progeny becomes merozoites

Front 5

Origin, target and progeny of merozoites

Back 5

Comes from liver cells or red cells, infects other red cells, and progeny is merozoites or gametocytes

Front 6

Origin, target and progeny of gametocytes

Back 6

Comes from red cells, infects mosquito, and progeny becomes sporozoites (following a number of intermediate stages, including gamete and zygote)

Front 7

This is the asymptomatic stage of Plasmodium infection

Back 7

Liver stage; sporozoites enter parenchymal cells of the liver. Asymptomatic bc one sporozoite infects just one hepatocyte.

Front 8

This is the symptomatic stage of Plasmodium infection

Back 8

Erythrocytic stage; merozoites enter red cells

Front 9

First stage that Plasmodium merozoite enters when it infects a red cell

Back 9

Ring stage

Front 10

This stage in the Plasmodium life cycle synthesizes a large volume of cytoplasm but remains uninuclear

Back 10

Ring stage as it undergoes cytoplasm synthesis

Front 11

When do we see multinucleate red cells?

Back 11

In plasmodium infection (merozoite in red cell), when cytoplasm synthesis is complete and multiple replications of the nucleus takes place

Front 12

How do merozoites replicate in red cells?

Back 12

First they enter a red cell, then enter a ring stage that synthesizes the cytoplasm of the future merozoites, then replicates its nuclei which will become the nuclei of the future metrozoites. Basically a soup of cytoplasm and nuclei is made, and these then divide off to become new metrozoites.

Front 13

Diagnostic stage of Plasmodium

Back 13

Erythrocytic forms observed in blood smears.

Front 14

Incubation period of malaria

Back 14

Typically 10-40 days. Up to 6-12 months in P. vivax. Up to years or decades in P. malariae (chronic asymptomatic erythrocytic phase).

Front 15

This disease is often misdiagnosed as influenza in non-endemic regions

Back 15

Malaria

Front 16

This disease causes anemia due to red blood cell destruction

Back 16

Malaria

Front 17

In the setting of chronic reinfection, this disease can result in splenomegaly

Back 17

Malaria

Front 18

Prodromal symptoms of malaria

Back 18

Headache, anorexia, fever, joint pain

Front 19

Symptoms of primary attack of malaria

Back 19

1 hour of shaking chills followed by a longer hot stage with headache and n/v. The cycle ends with a heavy sweat, which recurs with characteristic periodicity as blood stages become synchronized

Front 20

Why don't travelers with malaria present with characteristic periodic fevers?

Back 20

Because synchronous growth in the blood stage has not yet been established

Front 21

This species of malaria produces the most serious disease

Back 21

Plasmodium falciparum

Front 22

Incubation period of P. falciparum

Back 22

~2 weeks

Front 23

This species of Plasmodium infects red cells of all ages

Back 23

Plasmodium falciparum

Front 24

This species of Plasmodium preferentially infects reticulocyte (young red cells)

Back 24

Plasmodium vivax

Front 25

This species of Plasmodium preferentially infects ages red cells

Back 25

Plasmodium malariae

Front 26

Infection by this Plasmodium results in fever spikes every second day, then subsides in 3 weeks to low parasitemia; relapse with lower parasitemia may take place over next few months

Back 26

Plasmodium falciparum

Front 27

Microinfarcts are seen in infection with this parasite

Back 27

Plasmodium falciparum. Specific parasite proteins form "knobs" on the infected red cell membrane, binding endothelial cells and blocking capillaries.

Front 28

This parasite can cause cerebral disease (HA, coma, paralysis, death), intestinal hemorrhage, or tubular necrosis

Back 28

Plasmodium falciparum

Front 29

This species of malaria has no mechanism for relapse or delayed disease, thus it cannot survive mosquito-less winters of temperate zones.

Back 29

Plasmodium falciparum

Front 30

Diagnostic features of P. falciparum

Back 30

Only early forms (ring stages); later forms are not seen in peripheral blood because the knobs cause trapping in small vessels. Banana-shaped gametocytes.

Front 31

Banana-shaped gametocytes are pathognomonic for infection with this

Back 31

Plasmodium falciparum

Front 32

Alternative pathways for infection by malaria parasites

Back 32

Blood transfusion; perinatal, transplacental (rare)

Front 33

These parasites cause fever that spikes every second day

Back 33

P. falciparum, P. vivax

Front 34

T/F: all malaria can present with anemia

Back 34

True (due to rbc destruction)

Front 35

Hypnozoite

Back 35

Dormant stage of P. vivax

Front 36

This is the most common malaria of temperate zones

Back 36

P. vivax

Front 37

Schuffner's dots

Back 37

Prominent in late-stage infected cells of P. vivax; dots in other species of malaria are smaller and less distinct

Front 38

This is the most important feature of P. vivax on blood smear

Back 38

Schuffner's dots

Front 39

This parasite causes fever that spikes every third day

Back 39

P. malariae

Front 40

Incubation period of P. malariae

Back 40

(Longer than others) 5 weeks

Front 41

This malaria parasite can cause persistent infection decades-long (10-30 years)

Back 41

P. malariae

Front 42

This is a distinguishing feature of P. malariae on blood smear

Back 42

Band forms

Front 43

This is the most important feature of P. malariae on blood smear

Back 43

Yellow-brown malarial pigment

Front 44

This malaria parasite causes the lowest parasitemia

Back 44

P. malariae (just 6,000; vs. 300,000 and 20,000 in P. falciparum and P. vivax, respectively)

Front 45

Time before relapse for P. falciparum, vivax and malariae

Back 45

Weeks (f), months (v), years (m)

Front 46

This malaria parasite has the highest rates of resistance--chloroquine is useless against it

Back 46

Plasmodium falciparum

Front 47

This drug is used to eradicate the hypnozoite of P. vivax

Back 47

Primaquine

Front 48

This drug cannot be used in patients with a G-6-P dehydrogenase deficiency

Back 48

Primaquine

Front 49

T/F: malaria is a self-limiting disease

Back 49

True. Immunity is slow to arise, and requires repeat infections, but it is a self-limiting disease

Front 50

This is a non-malaria erythrocytic infection

Back 50

Babesiosis (Babesia microti)

Front 51

This disease has an endemic focus on Nantucket Island and elsewhere in the coastal northeast US

Back 51

Babesiosis (Babesia microti)

Front 52

This parasite can be mistaken for malaria on blood films because it has a similar ring stage

Back 52

Babesia

Front 53

These diseases are transmitted by dear ticks

Back 53

Lyme disease, Babesiosis

Front 54

Definitive host of Babesia

Back 54

Tick

Front 55

Infective stage of Babesia

Back 55

Parasites in salivary glands of tick

Front 56

Diagnostic stage of Babesia

Back 56

Trophozoites in stained blood film

Front 57

This parasite appears as tetrads of parasites in cross configurations on blood film

Back 57

Babesia

Front 58

Asplenia, old age and immunosuppression is a risk factor for this otherwise subclinical disease

Back 58

Babesiosis (Babesia microti)

Front 59

Symptoms of Babesiosis

Back 59

Hemolytic anemia, fevers, chills; severe complications are very rare

Front 60

This is why it is important to distinguish between Babesiosis and Malaria

Back 60

Chemotherapy differs. Babesiosis is also a less severe disease, whereas malaria can quickly progress to coma and death.

Front 61

5-20% of New Englanders are seropositive for this

Back 61

Babesiosis (Babesia microti)