What is the microorganism?

[Belleza156]

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A previously healthy 36-year-old man comes to
the emergency department 12 hours after the
sudden onset of increasingly severe abdominal
pain. He recently returned from a 3-week sailing
trip around Central America and several
Caribbean islands. His temperature is 38.3°C
(100.9°F), pulse is 96/min, respirations are
18/min, and blood pressure is 130/72 mm Hg.
Abdominal examination shows right lower
quadrant tenderness. His leukocyte count is
12,200/mm3 (70% segmented neutrophils, 6%
bands, 1% eosinophils, 20% lymphocytes, and
3% monocytes).

Exploratory laparotomy and an
appendectomy are done. Examination of the
appendix shows multiple mucosal ulcers.
Unicellular microorganisms are seen within the
exudates at the base of the ulcers. Some of the
microorganisms contain erythrocytes. Which of
the following is the most likely source of this
patient's infection?


(A) Being bitten by a sand fly
(B) Infection from a sexual partner
(C) Mosquito bite
(D) Undercooked freshwater fish
(E) Undercooked saltwater fish
(F) Water contaminated by human feces
(G) Water contaminated by infected snails

 

[Boardz]

A previously healthy 36-year-old man comes to
the emergency department 12 hours after the
sudden onset of increasingly severe abdominal
pain. He recently returned from a 3-week sailing
trip around Central America and several
Caribbean islands. His temperature is 38.3°C
(100.9°F), pulse is 96/min, respirations are
18/min, and blood pressure is 130/72 mm Hg.
Abdominal examination shows right lower
quadrant tenderness. His leukocyte count is
12,200/mm3 (70% segmented neutrophils, 6%
bands, 1% eosinophils, 20% lymphocytes, and
3% monocytes).

Exploratory laparotomy and an
appendectomy are done. Examination of the
appendix shows multiple mucosal ulcers.
Unicellular microorganisms are seen within the
exudates at the base of the ulcers. Some of the
microorganisms contain erythrocytes. Which of
the following is the most likely source of this
patient's infection?


(A) Being bitten by a sand fly
(B) Infection from a sexual partner
(C) Mosquito bite
(D) Undercooked freshwater fish
(E) Undercooked saltwater fish
(F) Water contaminated by human feces
(G) Water contaminated by infected snails

I would say F. rbcs in anything is usually a dead giveaway for entamoeba histolytica.

 

[Belleza156]

Yes! I couldn't remember which one it was that Goljan said you would see the erythrocytes in. Thanks!