A 32-year-old Hispanic male died suddenly at home. He had been at work and was apparently well the previous day. Little medical history was available, but he was known to have emigrated to the USA from a rural area of Brazil 3 years ago, and to have a long standing heart arrythmia.
Question 1 - Single Best Answer
Could an infectious disease have been responsible for this man's death, or do you suspect he just had a sudden heart attack?
A) infectious disease
B) only heart attack
Question 2 - Single Best Answer
What infectious disease(s) can cause heart problems and might be the underlying cause of this death?
A) Diphtheria, gonorrhea, tuberculosis, Chagas' disease
B) Streptococcus pyogenes infection/rheumatic heart disease, syphilis, tuberculosis, Chagas' disease
C) Infection of the heart by Streptococcus viridans, Staphylococcus epidermidis, or Staphylococcus aureus
D) Coxsackie virus infection, syphilis, diphtheria, pertussis
Autopsy revealed an enlarged, thin-walled heart with an apical left ventricular aneurysm. This apical aneurism is clearly visible in the photograph. The cause of death was listed as cardiac arrest. Question 3 - Single Best Answer
The pathology seen is most consistent with?
A) rheumatic fever
B) syphilis
C) diphtheria
D) Chagas'' disease
E) none of the above
Examination of histologic sections of the myocardium revealed inflammatory reactions, primarily mononuclear cell infiltrates, and nests or aggregates (arrow, right image) within muscle cells of tightly packed, nucleated, ovoid bodies, each 2-5 microns in diameter. Photos of the sections are shown. Other sections showed marked fibrosis of the myocardium.
Question 4 - Single Best Answer
This histologic examination demonstrated infection by?
A) Treponema pallidum
B) Histoplasma capsulatum
C) Trypanosoma cruzi
D) Streptococcus pyogenes
E) Leishmania donovani
Question 5 - Single Best Answer
In this case it was a postmortem histologic examination that established infection by T. cruzi. What test or tests is/are used to detect T. cruzi infections at an earlier stage than in this unfortunate individual?
A) serology
B) blood smear
C) xenodiagnosis
D) culture
E) all of the above
The history of chronic cardiac disease and prior residence in an endemic area such as rural Brazil should raise the suspicion of Chagas' disease. Based on serologic studies Trypanosoma cruzi was estimated to infect 10-20 million people in Central and South America of which 10% to 30% would be expected to develop clinical disease. Cardiac disease is the principal cause of death in Chagas' disease and sudden death is frequently due to cardiac arrest.
Question 6 - Single Best Answer
Pathogenesis of cardiac disease in T. cruzi infection includes?
A) inflammatory reactions
B) autoimmunity
C) differences in disease dependent upon the infecting strain of T. cruzi
D) an initial acute systemic phase with clinical evidence of heart damage in most people
E) A, B, C
Question 7 - Single Best Answer
What manifestations of Trypanosoma cruzi infection may be present in addition to those attributed to cardiac damage?
A) enlarged colon and/or esophagus (megacolon and/or megaesophagus)
B) premature birth, still birth, or neonatal death
C) fever, lymphadenopathy
D) unilateral eye (orbital) edema
E) all of the above
Question 8 - Single Best Answer
How is Chagas' disease transmitted?
A) mosquitoes and ticks
B) kissing
C) kissing bugs
D) blood transfusion
E) C and D
Question 9 - Single Best Answer
What is the reservoir of infection?
A) humans only
B) bugs only -- they pass the parasite transovarially
C) wild and domestic animals
Question 10 - Single Best Answer
Which of the following statements are applicable to the successful transmission and/or persistence of American trypanosomiasis in endemic areas?
A) the ability of the bugs to inject the infective stage into the saliva when they kiss you, from where they are swallowed and invade through the intestinal tract
B) the ability of the bugs to inject the infective stage directly into the blood stream
C) the ability of the parasite to invade and replicate in most types of nucleated cells
D) the resistance of trypanosomes to lysosomal products in the phagolysosome
E) antigenic variation in the circulating trypanosomes
Question 11 - Single Best Answer
The control of Chagas' disease is a major public health concern in endemic areas of Latin America. Several effective control programs have been introduced and dramatic reduction of transmission has been acheived in Brazil. Which of the following has NOT been a good approach to control?
A) vector control
B) improved housing
C) blood screening and treatment
D) reducing vertical transmission
E) mass treatment in hyperendemic areas
Question 12 - Single Best Answer
In the USA, Chagas' disease is important because of the large number of immigrants from endemic areas. At present, which of the following is considered of the LEAST medical or public health concern?
A) it could become a significant endemic infection
B) the blood supply could become contaminated
C) AIDS can cause the disease to be severe, requiring prolonged, expensive treatment
D) drugs are not highly effective and have dangerous side effects
E) all of the above are MAJOR concerns