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WASL Sample Questions : Science

Passage 4

Measles is an extremely contagious viral infection spread by the respiratory route. Figure 1 shows the course of measles from time of exposure to recovery from the infection.

After recovery from measles, the infected individual develops immunity or resistance to reinfection. Figure 1 shows the development of immunity indicated by the antibody level.

Figure 1 adapted from D. M. McLean, Virology in Health Care. ©1980 by Williams and Wilkins.

The number of reported cases of measles from 1950 through 1987 is depicted in Figure 2.

Figure 2 adapted from MMWR, "Summary of Notifiable Diseases." ©1986 Communicable Disease Center.

Following are some WASL sample questions on the above passage:

17. On Day 10 after exposure to measles, one could conclude that the greatest concentration of the measles virus would most likely be found in which of the following locations?
    1. Skin
    2. Mouth
    3. Blood
    4. Throat

    Answer: C

18. The introduction of the measles vaccine had which of the following effects, if any, on the occurrence of measles?
    1. It completely eradicated measles after 1963.
    2. It caused a decrease in the number of measles cases only during 1963.
    3. It caused a gradual decrease from 400,000 measles cases in 1963 to approximately 1,500 in 1983.
    4. The introduction of the measles vaccine had no effect on the occurrence of measles after 1963.

    Answer: C

19. Based on the information presented in the passage and in Figure 1, would it be possible to determine that a person had immunity against the measles virus 6 months after exposure?
    1. Yes; the level of protective antibodies against measles would be elevated 6 months after exposure.
    2. Yes; the virus would still be present in the respiratory tract to protect against reinfection.
    3. No; the level of protective antibodies against measles would be undetectable 6 months after exposure.
    4. No; the virus would no longer be present in the blood to protect against reinfection.

    Answer: A

20. On the basis of Figure 1, one can conclude that there is a rise in the antibody level when the:
    1. fever vanishes.
    2. rash first appears.
    3. cold symptoms are most severe.
    4. virus is present in the blood.

    Answer: A

21. According to Figure 2, the highest number of measles cases between 1981 and 1987 was approximately:
    1. 10.
    2. 100.
    3. 1,000.
    4. 5,000.

    Answer: D