A 24-year-old male Pakistani medical resident was seen in the emergency department at midnight, he was acutely ill with weakness, fever, abdominal pain, and diarrhea. He had visited relatives in Pakistan several months earlier. He had recently lost 20 lb inexplicably. Physical examination revealed hepatomegaly, splenomegaly, and lymphadenopathy. The patient had darkened areas of skin on his forehead and around his mouth. Based on the patient's symptoms and travel history, blood tests were ordered to rule out infection with a hemoflagellate, Laboratory tests, including routine hematology tests, revealed that the patient was anemic, with a hemoglobin level of 10 g/di. He also suffered from leukopenia and thrombocytopenia. Liver enzyme levels were slightly elevated. Giemsa-stained buffy coat smears were prepared and revealed a few macrophages containing oval, nonflagellated protozoan forms, about 2 to 3 um long. A large nucleus, a small kinetoplast, and an axoneme were visible in several parasites. 2. Name the three species belonging to this complex. In which parts of the world are these species located? 3. Which vectors are responsible for the transmission of this infection? 4. List four forms of infection caused by this genus of hemoflagellates. How does this patient's infection differ from the other three? 5. How is the diagnosis of this infection made? 6. What is the significance of the time of day (midnight) at which the patient was.

1. A 24-year-old male Pakistani medical resident was seen in the emergency department at
midnight, he was acutely ill with weakness, fever, abdominal pain, and diarrhea. He had visited
relatives in Pakistan several months earlier. He had recently lost 20 lb inexplicably. Physical
examination revealed hepatomegaly, splenomegaly, and lymphadenopathy. The patient had
darkened areas of skin on his forehead and around his mouth. Based on the patient's symptoms
and travel history, blood tests were ordered to rule out infection with a hemoflagellate,
Laboratory tests, including routine hematology tests, revealed that the patient was anemic, with a
hemoglobin level of 10 g/di. He also suffered from leukopenia and thrombocytopenia. Liver
enzyme levels were slightly elevated. Giemsa-stained buffy coat smears were prepared and
revealed a few macrophages containing oval, nonflagellated protozoan forms, about 2 to 3 um
long. A large nucleus, a small kinetoplast, and an axoneme were visible in several parasites. 2.
Name the three species belonging to this complex. In which parts of the world are these species
located? 3. Which vectors are responsible for the transmission of this infection? 4. List four
forms of infection caused by this genus of hemoflagellates. How does this patient's infection
differ from the other three? 5. How is the diagnosis of this infection made? 6. What is the
significance of the time of day (midnight) at which the patient was