Deck 48: Blood and Tissue Protozoa

Question 1

Resistance to chloroquine and mefloquine has been identified in which Plasmodium spp.?

A) P. ovale
B) P. vivax
C) P. falciparum
D) P. malariae

Answer 1

C
Chloroquine-resistant P.falciparum is present in almost all endemic areas other than Central America and the Caribbean.Increasing resistance to sulfadoxine-pyrimethamine and mefloquine has also been identified in P.falciparum.Therefore treatment with artemisinin combination treatments (ACTs), including artesunate-mefloquine, artemether-lumefantrine (Coartem), and artesunate-amodiaquine, has been instituted against P.falciparum.

Question 2

A thick ring, large nucleus, and bands across the cell and 6 to 12 merozoites in a mature schizont are all characteristics of which Plasmodium spp.?

A) P. vivax
B) P. ovale
C) P. falciparum
D) P. malariae

Answer 2

D

Question 3

The most frequent clinical signs of chronic Chagas disease involve the enlargement of which organ?

A) Heart
B) Liver
C) Spleen
D) Lung

Answer 3

A
Chronic Chagas disease may develop years after undetected infection or after the diagnosis of acute disease.Approximately 30% of patients may develop chronic Chagas disease, including cardiac changes and an enlargement of the colon and esophagus.Megacolon results in constipation, abdominal pain, and the inability to discharge feces.An acute obstruction may lead to perforation, septicemia, and death.However, the most frequent clinical signs of chronic Chagas disease involve the heart, in which enlargement of the heart and conduction changes are commonly seen.

Question 4

In cases of malaria, the primary exoerythrocytic cycle occurs in the:

A) blood.
B) lung.
C) liver.
D) lymph nodes.

Question 5

Match the vector with the organism it infects. Answers may be used more than once.a.Anopheles mosquito
b.Tsetse fly
c.Sandfly
d.Reduviid bug
Trypanosoma cruzi

Question 6

Cerebral malaria is considered to be the most serious complication and major cause of death with which species of Plasmodium spp.?

A) P. vivax
B) P. falciparum
C) P. ovale
D) P. malariae

Question 7

Ring forms and a "Maltese cross" were observed in a blood smear.The vector that transmits this disease is a(n):

A) tick.
B) tsetse fly.
C) anopheles mosquito.
D) sandfly.

Question 8

Match the vector with the organism it infects. Answers may be used more than once.a.Anopheles mosquito
b.Tsetse fly
c.Sandfly
d.Reduviid bug
T.brucei rhodesiense

Question 9

Stage I of trypanosomiasis characteristically involves systemic trypanosomiasis infection without central nervous system (CNS)involvement.Lymphadenopathy is also a feature of this disease.The trypomastigotes of which protozoa are involved?

A) Trypanosoma cruzi
B) T. rangeli
C) T. brucei rhodesiense
D) T. brucei gambiense

Question 10

MATCHING
Match the size and shape of the parasitized RBCs as they appear in Giemsa-stained thin blood smears. Answers may be used more than once.a.Normal shape and size
b.Normal shape; size may be normal or slightly smaller
c.1.5 to 2.0 times larger than normal; oval to normal
d.60% of cells are larger than normal and oval
Plasmodium vivax

Question 11

MATCHING
Match the size and shape of the parasitized RBCs as they appear in Giemsa-stained thin blood smears. Answers may be used more than once.a.Normal shape and size
b.Normal shape; size may be normal or slightly smaller
c.1.5 to 2.0 times larger than normal; oval to normal
d.60% of cells are larger than normal and oval
P.knowlesi

Question 12

MATCHING
Match the size and shape of the parasitized RBCs as they appear in Giemsa-stained thin blood smears. Answers may be used more than once.a.Normal shape and size
b.Normal shape; size may be normal or slightly smaller
c.1.5 to 2.0 times larger than normal; oval to normal
d.60% of cells are larger than normal and oval
P.malariae

Question 13

Chagas disease is caused by:

A) Trypanosoma rangeli.
B) T. cruzi.
C) T. brucei rhodesiense.
D) T. brucei gambiense.

Question 14

MATCHING
Match the size and shape of the parasitized RBCs as they appear in Giemsa-stained thin blood smears. Answers may be used more than once.a.Normal shape and size
b.Normal shape; size may be normal or slightly smaller
c.1.5 to 2.0 times larger than normal; oval to normal
d.60% of cells are larger than normal and oval
P.falciparum

Question 15

MATCHING
Match the size and shape of the parasitized RBCs as they appear in Giemsa-stained thin blood smears. Answers may be used more than once.a.Normal shape and size
b.Normal shape; size may be normal or slightly smaller
c.1.5 to 2.0 times larger than normal; oval to normal
d.60% of cells are larger than normal and oval
P.ovale

Question 16

Plasmodium vivax is suspected in a patient who has been traveling for months in the tropics.Blood was collected in a lavender top tube; however, the slide was not prepared for examination until the next day because the specimen came in on the night shift.Once the slide was prepared and examined, Schüffner dots were not visible.Which one of the following statements explains this discrepancy?

A) Schüffner dots are not characteristic of P. vivax infections.
B) The blood film was most likely incorrectly prepared.
C) The blood should have been collected in a red top tube.
D) The blood remained in the tube too long, yielding false-negative results.

Question 17

Humans contract Chagas disease when the reduviid bug defecates while taking a blood meal and the parasites in the feces are rubbed or scratched into the bite wound or onto mucosal surfaces.Which stage in the blood infects the host cells?

A) Amastigote
B) Epimastigote
C) Trypomastigote
D) Promastigote

Question 18

The vector Glossina palpalis group transmits the Trypanosoma brucei gambiense organism.The diagnostic stage is the:

A) amastigote.
B) epimastigote.
C) trypomastigote.
D) promastigote.

Question 19

Delicate ring forms and crescent-shaped gametocytes are the only forms normally observed in the peripheral blood of which Plasmodium spp.?

A) P. vivax
B) P. malariae
C) P. falciparum
D) P. ovale

Question 20

In Trypanosoma brucei rhodesiense trypanosomiasis infections, CNS invasion occurs early.The disease progresses rapidly, and death may occur before extensive CNS involvement.Inflammation of which organ is more common and severe with this disease form?

A) Kidney
B) Lungs
C) Liver
D) Heart

Question 21

Match the vector with the organism it infects. Answers may be used more than once.a.Anopheles mosquito
b.Tsetse fly
c.Sandfly
d.Reduviid bug
T.brucei gambiense

Question 22

Match the vector with the organism it infects. Answers may be used more than once.a.Anopheles mosquito
b.Tsetse fly
c.Sandfly
d.Reduviid bug
T.rangeli