A 22-year-old merchant seaman developed weakness, chills and fever while on board ship which had departed two weeks previously from a west African port. In the 4 days following the initial symptoms, he became acutely ill with headache, fever (l03F), severe diarrhea, abdominal cramps and dyspnea.
Question 1 - Single Best Answer
Does the acute illness on board ship and recent departure from west Africa specifically indicate any of the diagnoses listed?
A) A viral hemorrhagic fever, as yellow fever
B) Typhus
C) Malaria
D) Typhoid fever
E) It could be any of the above
He was treated by the ship's doctor with a tetracycline and later penicillin but continued to have daily fevers up to l06F. He also had persistent diarrhea and became extremely weak. Five days after onset of acute disease, the ship arrived in the USA and he was immediately hospitalized.
Question 2 - Single Best Answer
Why was he treated with penicillin and tetracycline?
A) the doctor thought he had hemorrhagic fever
B) the doctor thought he had amebiasis
C) the doctor thought he had typhoid fever
D) the doctor thought he had traveller's diarrhea
E) the doctor didn't have any specific means of diagnosis, but thought it might be a bacterial infection
Physical examination on admission showed an agitated, dehydrated, hypotensive white male with tachycardia, an enlarged spleen and a temperature of l00F. A series of tests were ordered, but within 8 hours the patient complained of severe headache, became severely disoriented and developed a marked hyperthermia (l08F); this was quickly followed by aspiration of vomitus and respiratory arrest. Attempts at resuscitation failed.
Question 3 - Single Best Answer
In this case the immediate cause of death was respiratory arrest following aspiration but secondary to a severe disease process. Diagnostic tests were not completed but a blood smear was taken before death and subsequently examined. The stained blood smear, as shown, clearly established which diagnosis?
A) Falciparum malaria (malignant tertian malaria)
B) Vivax malaria ( benign tertian malaria)
C) Babesiosis
D) African trypanosomiasis
E) None of the above
Question 4 - Single Best Answer
Who else in the hospital is now at risk for this disease?
A) the doctors
B) the technicians that drew the blood following universal precautions
C) any patients with whom the seaman had casual contact
D) no one else is at risk
Question 5 - Single Best Answer
In falciparum malaria?
A) An acute, severe febrile illness with no pattern of recurrent fever and a fatal outcome are rare.
B) The symptoms and fatal result could have been induced by infection with any of the Plasmodia which cause malaria.
C) If the seaman had been taking the usual malarial prophylaxis (chloroquine) infection would have been prevented.
D) The failure to consider the possibility of malaria at the onset of symptoms was a major error.
E) It is understandable that malaria was not considered because it is a decreasing problem in tropical areas and infection requires a prolonged stay in an endemic area.
Falciparum malaria is life threatening in non-immune individuals and the diagnosis and initiation of treatment are emergency procedures. It is critical to determine if the patient is infected with P. falciparum rather than one of the less virulent malarial species and to consider the geographic area of exposure to determine if treatment for drug resistant (chloroquine resistant) malaria should be initiated.
The diagnosis of malaria is made routinely from a stained smear of peripheral blood and the species of Plasmodium identified by the morphologic features of the erythrocytic stages. Diagrams comparing the diagnostic stages of the 3 most common malarial species are pictured: Plasmodium vivax, Plasmodium malariae and Plasmodium falciparum.
Trophozoites: Top horizontal row is P. vivax, middle row is P. malariae and bottom row is P. falciparum.
Schizonts: Top row is P. vivax, 2nd row P. malariae, and bottom P. falciparum. NB schizonts of P. falciparum are rarely seen in a peripheral blood smear.
Gametocytes: Top row is P. vivax, 2nd row P. malariae, bottom row P. falciparum.
Question 6 - Single Best Answer
In the blood smear from the present case, which are NOT important differentiating features of falciparum malaria?
A) Numerous RBC infected, frequently 2 parasites (rings) per RBC and applique forms ( parasite appears applied to surface of RBC).
B) Infected RBC not enlarged.
C) Ring stage small, no large trophozoites or schizonts (dividing stages) seen.
D) None of the above
Question 7 - Single Best Answer
For the diagnosis of malaria, examination of a thick blood smear and a thin smear are routine procedures. The thick smear permits a larger volume of blood to be examined and is more efficient in detecting infection than a thin smear but does not show the morphologic detail and changes in the infected RBC useful in species differentiation. 
A microscopic examination ( l000X) of a thick smear is shown. Can a specific diagnosis be made?
A) Yes. Falciparum malaria
B) Yes. Vivax malaria
C) No. It is malaria but it can't be speciated
D) No. Nothing diagnostic on the slide
E) I don't know
Question 8 - Single Best Answer
Two weeks after the seaman died, a farmer from a neighboring community came down with similar symptoms. What is the likelihood that he could have gotten malaria from the seaman?
A) it is impossible
B) it is highly likely
C) it is likely only if he had been in the same community as the seaman outside the hospital