Question 1

Which of the following best describes the primary mechanism by which HIV evades the host immune system?

Accepted Answer

HIV mutates rapidly, leading to antigenic variation and escape from immune detection.

Question 2

A patient presents with a persistent cough and fever. Laboratory tests reveal the presence of Mycobacterium tuberculosis. Which phase of HIV infection is most likely to be associated with the development of tuberculosis as an opportunistic infection?

Accepted Answer

Phase 3: AIDS (severe immunodeficiency)

Question 3

Which cell surface receptor is essential for HIV entry into CD4+ T cells?

Accepted Answer

CD4

Question 4

A researcher is studying the effect of antiretroviral therapy (ART) on HIV replication. Which class of drugs inhibits the reverse transcription of viral RNA into DNA?

Accepted Answer

Nucleoside reverse transcriptase inhibitors (NRTIs)

Question 5

Which equation best represents the exponential decline of CD4+ T cell count over time in untreated HIV infection?

Accepted Answer

$$N(t) = N_0$ e$$^{-kt}$$

Question 6

Which of the following is a major challenge in developing an effective HIV vaccine?

Accepted Answer

HIV mutates rapidly, resulting in high antigenic variability.

Question 7

A patient exposed to rabies receives post-exposure prophylaxis (PEP). What is the primary goal of PEP in rabies infection?

Accepted Answer

To stimulate the immune system before the virus reaches the nervous system.

Question 8

Which of the following statements about the influenza virus is correct?

Accepted Answer

Influenza virus undergoes antigenic drift and shift, leading to new strains.

Question 9

A child presents with a sore throat and red, swollen tonsils. Streptococcus pyogenes is isolated from the throat swab. Which disease is most likely?

Accepted Answer

Streptococcal pharyngitis (strep throat)

Question 10

Which of the following best explains why HIV-infected individuals are at increased risk for fungal infections such as Pneumocystis pneumonia?

Accepted Answer

HIV destroys CD4+ T cells, impairing cell-mediated immunity.

Question 11

Which diagnostic method is most commonly used for initial screening of HIV infection?

Accepted Answer

Enzyme-linked immunosorbent assay (ELISA) for HIV antibodies

Question 12

A patient with AIDS develops Kaposi's sarcoma. Which pathogen is most likely responsible for this condition?

Accepted Answer

Human herpesvirus 8 (HHV-8)

Question 13

Which of the following is a key difference between latent and active HIV infection in macrophages?

Accepted Answer

Active infection leads to production and release of new virions.

Question 14

Which of the following best describes the role of the CCR5 co-receptor in HIV infection?

Accepted Answer

CCR5 acts as a co-receptor facilitating HIV entry into CD4+ T cells.

Question 15

A patient with influenza is treated with oseltamivir (Tamiflu). What is the mechanism of action of this drug?

Accepted Answer

Inhibits neuraminidase, preventing viral release from host cells

Question 16

Which of the following equations correctly models the basic reproductive number ($$R_0) $$for an infectious disease?

Accepted Answer

$$R_0$$ = \frac{\beta}{\gamma}$$

Question 17

Which of the following is the most common route of HIV transmission worldwide?

Accepted Answer

Heterosexual intercourse

Question 18

A patient with AIDS is found to have a CD4+ T cell count of 180 cells/mm³. According to the progression chart, which phase of HIV infection is this patient most likely in?

Accepted Answer

Phase 3: AIDS

Question 19

Which of the following best explains why rabies infection is almost always fatal once symptoms appear?

Accepted Answer

Rabies virus infects the central nervous system, leading to irreversible damage.

Question 20

Which of the following is a major reason for the emergence of new influenza strains each year?

Accepted Answer

Influenza virus undergoes frequent genetic reassortment.

Theme 12

Study Guide - Practice Questions

Study Guide - Flashcards