Deck 22: Serological and Molecular Diagnosis of Parasitic and Fungal Infections

Question 1

A parasite accesses a target cell in a host,thus hiding its antigens from the host's immune system.This survival strategy is known as:

A) antigenic mimicry.
B) immunologic subversion.
C) antigenic concealment.
D) shedding.

Answer 1

antigenic concealment.

Question 2

Suppose a parasite invades a patient and causes disease.The patient develops an immune response and has some resistance to the parasite but is not cured.This outcome is considered what type of host-parasite interaction?

A) Symbiosis
B) Commensalism
C) Sterilizing immunity
D) Concomitant immunity

Answer 2

Concomitant immunity

Question 3

A 27-year-old female patient who is pregnant is undergoing serological testing as a precaution because of a recent food poisoning episode in which she ate undercooked pork at a picnic.The laboratory tests revealed positive IgG antibodies and negative IgM antibodies to toxoplasmosis.What do these test results indicate?

A) She has an active infection, and there is risk of transmission to the fetus.
B) She does not have an active infection, and there is no risk to the fetus.
C) She has a chronic infection, and there is minimal risk to the fetus.
D) She has an active infection, and there is no risk to the fetus.

Answer 3

She does not have an active infection, and there is no risk to the fetus.

Question 4

A patient has been diagnosed with tapeworm.Identify the type of parasitic organism involved.

A) Protozoa
B) Helminth
C) Ectoparasite
D) Host

Question 5

A patient with candidiasis is considered to have which type of mycotic infection?

A) Subcutaneous
B) Systemic
C) Opportunistic
D) Superficial

Question 6

A complement fixation test for Histoplasma antibodies shows a 1:32 titer.This means the patient is negative for Histoplasma infection.

Question 7

Which statement best describes antigenic variation of a parasite?

A) Parasites can change their antigens or create novel antigens.
B) Parasites do not have any surface antigens.
C) Parasites are ingested by macrophages, and antigens are denatured.
D) Parasites have similar host antigens.

Question 8

Serology assays are useful in the diagnosis of Aspergillus infections from bronchial lavage samples in immunocompromised patients.

Question 9

A patient presents with a fungal infection.Which components of the immune system are activated early in the course of the patient's infection?

A) Macrophages and dendritic cells
B) Natural killer cells and antibodies
C) Polysaccharides and chitins
D) T cells and B cells

Question 10

An example of a fungal organism that commonly causes systemic infections is:

A) Malassezia furfur.
B) Trichophyton species.
C) Cryptococcus neoformans.
D) Candida albicans.

Question 11

A parasite that causes the immune system to increase protein production to distract the immune system is using which survival strategy?

A) Antigen shedding
B) Antigenic mimicry
C) Immunologic subversion
D) Immunologic diversion

Question 12

What approach can be used to decrease the chance of a false-positive result when performing latex agglutination to identify Cryptococcus infections?

A) Mixing the specimen with India ink
B) Pretreating the specimen with heat and pronase
C) Freezing the specimen
D) Waiting for the patient to be symptomatic before testing

Question 13

A patient who has recently traveled to Africa presents to the physician with a possible parasitic infection.The physician orders serological testing.Which of the following conditions is best detected via serological testing?

A) Ascariasis
B) Lyme disease
C) Malaria
D) Toxoplasmosis

Question 14

To correctly determine an infection with toxoplasmosis within the last 12 months,both IgG and IgM should be negative.

Question 15

A patient is diagnosed with coccidioidomycosis.This infection can be classified as:

A) subcutaneous.
B) systemic.
C) opportunistic.
D) superficial.

Question 16

Suppose a parasite invades a patient and causes disease.The patient develops immunity and is ultimately cured.This outcome is considered what type of host-parasite interaction?

A) Symbiosis
B) Commensalism
C) Sterilizing immunity
D) Concomitant immunity

Question 17

Eosinophilia and an increase in which immunoglobulin play a role in the defense against parasites?

A) IgA
B) IgD
C) IgE
D) IgG