Deck 23: Spirochete Diseases

Question 1

Viral load testing is of most clinical utility in all of the following situations EXCEPT:

A) initial diagnosis of HIV infection when antibody tests are positive
B) monitoring patients during antiretroviral therapy
C) setting a baseline before antiretroviral therapy has begun
D) investigating a patient's sudden drop in T-cell count

Answer 1

initial diagnosis of HIV infection when antibody tests are positive

Question 2

Which is most likely a positive Western blot result for infection with HIV?

A) band at p24
B) band at gp60
C) bands at p24 and p31
D) bands at p24 and gp120

Answer 2

bands at p24 and gp120

Question 3

A 22-year-old male sees his physician for an annual checkup.He reported having flu-like symptoms including fever,sore throat,and lymphadenopathy several months ago.He has lost about 10 pounds but otherwise feels fine.Since he reports that a former girlfriend told him she is HIV positive,the physician recommends testing.An ELISA test is positive,a Western blot is positive,and a CD4+ T-cell count is 500/ $\mu$ L.What do these results indicate?

A) He has AIDS.
B) He has recovered from HIV infection.
C) He is HIV positive but in a latent stage.
D) He has an opportunistic infection and not HIV.

Answer 3

He is HIV positive but in a latent stage.

Question 4

All of the following body fluids are considered to be possible routes of transmission for HIV even if there is no visible sign of blood EXCEPT:

A) spinal fluid
B) semen
C) urine
D) vaginal secretions

Question 5

What is the main mechanism of action of nucleoside analogue drugs such as zidovudine?

A) inhibiting the action of reverse transcriptase
B) blocking entry of HIV into host cells
C) acting as protease inhibitors
D) preventing release of HIV particles

Question 6

Which test would be most reliable in detecting HIV infection in an infant younger than 18 months of age?

A) ELISA test for antibody
B) testing for p24 antigen
C) Western blot
D) DNA PCR testing

Question 7

Which technique is most widely used for the confirmation of a positive serologic assay for antibodies against HIV?

A) enzyme-linked immunosorbent assay (ELISA)
B) complement fixation
C) Western blot assay
D) polymerase chain reaction

Question 8

What is different about the replication cycle of HIV that separates it from many other RNA viruses?

A) Viral RNA is used to make cDNA.
B) Viral RNA replicates itself directly to make new RNA.
C) The virus reproduces only in B cells.
D) Proviral DNA makes new viral particles immediately.

Question 9

A 25-year-old male presents to the public health clinic complaining of flu-like symptoms.The man has been an IV drug user and prostitute for the last 5 years.HIV antibody screening is positive.Subsequently,antibodies are found to have specificity for p24,gp120,p31,and gp41.This patient has:

A) current HIV infection
B) indeterminate HIV infection
C) lack of HIV infection
D) infection with some other virus

Question 10

A patient has serum tested for HIV antibodies by ELISA,and the test is positive.The patient's serum is retested in duplicate with two more positive results.What should be done next?

A) Patient is diagnosed with acute HIV infection.
B) Serum is tested for antibodies against hepatitis C virus.
C) HIV Western blot assay is performed on patient's serum.
D) Results mean that patient had HIV in the past but not now.

Question 11

The HIV p24 protein encodes:

A) group-specific antigen (GAG)
B) the receptor for host cells (ENV)
C) reverse transcriptase (POL)
D) none of these

Question 12

Which of the following HIV-encoded proteins/glycoproteins is the receptor for host cells?

A) p24
B) gp120
C) gp41
D) p31

Question 13

All of the following conditions would indicate AIDS EXCEPT:

A) a CD4+ count of less than 200 cells/ $\mu$ L
B) Kaposi's sarcoma
C) esophageal candidiasis
D) infectious mononucleosis

Question 14

The Western blot test used to confirm HIV is an example of which of the following?

A) immunofixation
B) immunoelectrophoresis
C) double diffusion
D) passive agglutination