Practice Questions for Test 2

1. Explain the difference between a virus and a cell. From a public health standpoint, explain the difference in consequences for treatment of viral and cellular pathgenic infections.

2. How do viruses replicate? How do we count the number of viruses in a sample? What are some problems that arise with counting the number of influenza virions? HIV virions?

3. Compare and contrast the structure of viruses poliovirus, influenza virus, and HIV. Explain how their structures relate to their effects on the host.

4. What does "H1N1" mean? What is the significance of the H and N numbers for predicting virulence of a flu strain? How does chromosome sequence analysis lead to predictions of virulence?

5. Compare and contrast the infection and transmission mechanisms of polio, influenza, and HIV. Explain the relationship between incubation/infection times and transmission.

6. The following data represent HIV-positive diagnoses; AIDS diagnoses; and AIDS deaths in the UK:

Explain what the graph shows is happening, in terms of HIV infections, AIDS, and the interconnections. Explain the most likely reasons for the changes seen.

7. Compare and contrast the approaches to polio prophylaxis in the USA and in developing countries such as India. Include the roles of the different types of vaccine (Sabin versus Salk).

8. What public health measures are taken today to control the spread of H1N1 flu? If influenza virus today were to reach mortality levels comparable to 1918, how would our current public health measures have to change?

9. What public health measures are taken today to control the spread of AIDS? How have public health measures against AIDS changed over the past decade, and why? How has the demographic of AIDS and HIV-infection changed, and why?