Question

35. New York city population is 8.6 million. Currently they report a total of 25,398 covid 19 cases. What is the current prevalence of covid 19 in NYC? a. 0.295% b. 2.95% c. 5% d. 0.01% e. 7%

36. A hypothetical example. In city A, with a population of 100,000 people, the weekly number of new cases of covid 19 was 100 while in city B, with a population 1,000,000, the reported weekly number of new cases was 1000. The news reported that city B experiences a major epidemic while conditions in city A are under control. What is the problem (if there is a problem) with this statement.

a. There is no problem because city B indeed has more cases

b. This is a fallacy, because the reporters did not adjust for population size

c. This is a fallacy, because the reporters should have calculated the prevalence of the disease

d. This is a fallacy, because the reporters should have calculated the fatality rate of the disease e. None of the above

37. Calculate and compare the incidence rates (IC) of the two cities a. IC(A) > IC(B) b. IC(A) < IC(B) c. IC(A) = IC(B)

38. Of the 1000 reported sick in city B, 20 died. Calculate the case fatality rate a. 0.2% b. 2% c. 20% d. 2 new cases per day e. 5 new cases per day 39. However, if there are many minor cases that don’t report to the hospital, how should that bias the estimate of the case fatality rate?

a. It would not bias the estimate

b. It would over-estimate it because they overestimate the denominator

c. It would over-estimate it because they underestimate the denominator

d. It would under-estimate it because they overestimate the denominator

e. It would under-estimate it because they underestimate the denominator

40. Calculate R0 for a sexually transmitted diseases based on the following parameter values: B=0.03 (infections/day) y=0.01 S = 100 (hint - use your notes to figure out which correct formulation of R0 to use) a. 300 b. 30 c. 3 d. 0.3 e. 2.5

41. Can this pathogen invade into this population? a. Pathogen can invade such a population and cause an epidemic b. Pathogen can invade such a population but not cause an epidemic rather will maintain a constant endemic level of infection c. Pathogen cannot invade such a population and would die out.

42. What is the contact structure for such a disease? a. Random b. Directed c. Environmental

43. What is the mode of transmission for vector-borne diseases? a. Density-dependent transmission b. Frequency-dependent transmission c. None of the above

44. Global warming is expected to ____ R0 of vector-borne diseases a. Decrease b. Increase c. Not affect

45. Global warming could impact which parameter of R0 for vector-borne diseases’ a. Biting rate b. Pathogen external incubation rate c. Host recovery rate d. Biting rate and Pathogen external incubation rate e. Host recovery rate and Pathogen external incubation rate

46. The dilution effect hypothesis posits that a. R0 should increase with species number in the community b. R0 should decrease with species number in the community c. R0 should not be affected species number in the community

47. Using the metapopulation analogy at the individual host level a. Host recovery is analogous to transmission while transmission is equivalent to host recovery b. Host recovery is analogous to pathogen local population extinction while transmission is equivalent to migration and recolonization

48. What is a problem with this analogy? a. Following migration, habitat patches cannot go extinct b. Following extinction due to host recovery, habitat patches (hosts) become uninhabitable (for a while) c. Following extinction due to pathogen transmission, further transmission is not possible d. There is no problem with this analogy

49. “Given enough time a state of peaceful coexistence eventually becomes established between any host and parasites”. What is the problem with this statement (choose the best answer)? a. There is no problem, because parasites should always evolve to become benign because killing their host would prevent their transmission b. Maximizing transmission rates causes increase in virulence as a biproduct. Therefore, a benign pathogen is expected to be outcompeted by a more virulent strain because the latter is more transmissible. c. A highly virulent strain will be outcompeted by a more benign strain because the latter would have a longer infectious period.

50. From a Darwinian medicine perspective, taking a pill to reduce your fever would be a. a good idea because fever makes you feel bad b. a bad idea because fever is a protective mechanism against pathogens c. a bad idea because pills are chemicals, and we should only use herbal products

Answer 1

35.

New york city population → 9.6 millons · Number of covid cases → 25,398. Prevalence of covid-19 in NYC 7 25.398 100 = 2.95% 8.b xide

Option B is the right one.

36.

City A has 100,000 people and new covid cases reported are 100

City B has population 1,000,000 has covid cases reported 1000.

In both populations, new cases reported is 0.1.

Option B is the right one. The population size needs to adjusted while reporting.

37.

The incidence rate is same in both populations.

Option C is the right one.

38.

Fatality rate is ---

  

90x100 = 2. סטט

OPtion B is right option.