Nr503 EPIDEMIOLOGY FINAL EXAM

Which of the following is a condition which may occur during the incubation period? Chicken pox is a highly communicable disease. It may be transmitted by direct contact with a person infected with the varicella-zoster virus (VZV). The typical incubation time is between 10 to 20 days. A boy started school 2 weeks after showing symptoms of chicken pox including mild fever, skin rash, and fluid-filled blisters. One month after the boy returned to school, none of his classmates had been infected by VZV. The main reason was: Contact was after infectious period The ability of a single person to remain free of clinical illness following exposure to an infectious agent is known as: Which of the following is characteristic of a single-exposure, common-vehicle outbreak? What is the diarrhea attack rate in persons who ate both ice cream and pizza? What is the overall attack rate in persons who did not eat ice cream? Nr503 EPIDEMIOLOGY FINAL EXAM EPIDEMIOLOGY Ice cream only • They were directly exposed to persons who did eat the infective food item • Diarrhea is a general symptom consistent with a number of illnesses • There may have been an inaccurate recall of which foods were eaten (all of the above) Which of the food items (or combination of items) is most likely to be the infective item(s)? Which of the following reasons can explain why a person who did not consume the infective food item got sick? An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty- seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p.m. on September 24 and 8 p.m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. Calculate the attack rate among all students at the boarding school. The answer is found by dividing the total number of cases (57) by the total number of students (846). This equals 6.7%. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty- seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p.m. on September 24 and 8 p.m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. Calculate the attack rates for boys and girls separately. For boys, the attack rate includes all cases (40 + 3) divided by the total number of students who are boys (380 + 46). The attack rate is 10.1%. For girls, the attack rate includes all cases (12 + 2) divided by the total number of students who are girls (343 + 77). The attack rate is 3.3%. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty- seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p.m. on September 24 and 8 p.m. on September 25. The ill students lived in dormitories Nr503 EPIDEMIOLOGY FINAL EXAM EPIDEMIOLOGY that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. What is the proportion of total cases occurring in boys? The proportion of cases occurring in boys is equal to the number of cases in boys divided by the total number of cases (43/57). This equals 75.4%. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty- seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p.m. on September 24 and 8 p.m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. What is the proportion of total cases occurring in students who live in dormitories?