1.A 37-week-old infant was delivered by cesarean section and discharged from a Connecticut hospital when he was 10 days old. Two days later he was lethargic and had a fever. When he was readmitted to the hospital, he had multiple brain abscesses caused by Citrobacter diversus. After a prolonged illness, the baby died. A second infant with a normal pregnancy and delivery died of C. diversus meningitis after a short illness. Nine infants in the hospital nursery had umbilical cord colonization by C. diversus. Environmental cultures were negative for hospital equipment.
a. What is the normal habitat of this gram-negative, facultatively anaerobic, non-endospore-forming, lactose-positive rod? b.Provide a plan for identifying the source of infection and preventing further infection. (30 points)
2) Salmonella heidelberg gastroenteritis occurred on three cruises aboard the T.S.S. Festivale. Figure 14.4 shows on-board clinic visits for diarrheal illness between February 10 and March 3.
a. Explain the incidence pattern shown on the graph. b. What are probable modes of transmission? c.. What changes would you recommend before the ship books more cruises after March 3?(30 points)
3. A 56-year-old Army officer received a smallpox vaccination at a military vaccination clinic. Within 2 weeks, a painful ulcer was noted at the vaccination site. Because of the appearance of an increasing number of peripheral lesions and because of continued enlargement of the initial ulcer, he was treated. Eventual recovery was complicated by Pseudomonas sepsis and the need for a skin graft at the vaccination site. What was the cause of the ulcer and lesions, and what were the treatments? What caused the Pseudomonas infection? (30 points)
4. In the West Branch Study what are your thoughts on how the investigation was done? It is a classic study. (10 Points)