Exam 4 (MLS) - (CH 29) Clinical Virology Textbook Review Questions

Question 1

Which of the following statements is true of most viral infection detection?
A. The sensitivity of viral culture increases 3 days after the acute onset of symptoms.
B. Culture test methods are least susceptible to the impact of contamination.
C. Ideal specimens with the highest viral load will be in the earliest stage of infection.
D. Viral shedding is highest at the end of the infection; therefore, ideal specimens are collected at this time.

Answer 1

C. Ideal specimens with the highest viral load will be in the earliest stage of infection.

Question 2

Many viruses produce distinctive and characteristic visual changes in infected cells referred to
A. cytopathic effect.
B. neoplastic changes.
C. dysplasia.
D. Bethesda effect.

Answer 2

A. cytopathic effect.

Question 3

Which of the following are characteristics of primary cell cultures?
A. They are obtained from tissue removed from an animal.
B. Minimal cell division occurs.
C. They only be passaged a few times.
D. All of the above.

Answer 3

D. All of the above.

Question 4

These are giant multinucleated cells resulting from cell fusion as a consequence of viral infection.
A. Hemagglutination
B. Syncytia
C. Morulae
D. Papilla

Answer 4

B. Syncytia

Question 5

In which of the following is the cytomegalovirus shed?
A. Saliva
B. Vomit
C. Respiratory droplets
D. All of the above

Answer 5

A. Saliva

Question 6

The arenaviruses infect ___, and humans are exposed to the disease by zoonotic transmission.
A. Bats
B. Pigs
C. Rodents
D. Fish

Answer 6

C. Rodents

Question 7

The arenaviruses infect ___, and humans are exposed to the disease by zoonotic transmission.
A. Bats
B. Pigs
C. Rodents
D. Fish

Answer 7

C. Rodents

Question 8

Which of the following viruses cause hemorrhagic fever with renal syndrome?
A. Adenovirus
B. Hantaan virus
C. Ebola virus
D. Norovirus

Answer 8

B. Hantaan virus

Question 9

Rift Valley fever virus targets the
A. brain and liver.
B. kidneys.
C. spleen and colon.
D. All of the above.

Answer 9

A. brain and liver.

Question 10

Dengue virus has the nickname
A. capillariasis.
B. river blindness.
C. breakbone fever.
D. bad air disease.

Answer 10

C. breakbone fever.

Question 11

An abrupt, drastic change that can result in a new influenza H or N antigen is most accurately described as a(n)
A. antigenic drift.
B. antigenic shift.
C. plasmid-mediated translocation.
D. genetic reassortment.

Answer 11

B. antigenic shift.

Question 12

Which opportunistic infections or conditions are used as indicators of acquired immunodeficiency syndrome (AIDS)?

Answer 12

Some opportunistic infections and conditions associated with AIDS include candidiasis, cryptococcal meningitis, cryptosporidiosis, histoplasmosis, persistent HSV infections, mycobacterial infections, recurrent pneumonia, and Kaposi sarcoma.

Question 13

Which immunologic markers are used to diagnose human immunodeficiency virus (HIV) infection?

Answer 13

Testing for HIV-specific antigens and antibodies is important in the diagnosis of HIV infection, including antibodies to viral antigens p24, p31, gp41, and gp120/ 160.

Question 14

What disease does Epstein-Barr virus (EBV) produce? What complications may result from EBV infections?

Answer 14

EBV causes infectious mononucleosis. EBV has been associated with Burkitt lymphoma, nasopharyngeal carcinoma, and the development of B-cell lymphoproliferative disorder or lymphoma. Other EBV complications include splenic hemorrhage, hepatitis, thrombocytopenia purpura with hemolytic anemia, Reye syndrome, and encephalitis.

Question 15

How is acute hepatitis B virus (HBV) infection differentiated from chronic infection? Which markers indicate resolution of the infection?

Answer 15

Signs and symptoms of acute HBV infection include fever, anorexia, and hepatic tenderness, with jaundice occurring in 30% to 50% of infected older children and adults. The immune response slowly clears HBV from the body, and most patients become noninfectious. Some patients become HBV carriers for longer than 6 months, and these patients are very likely to carry the virus for much longer. Chronic hepatitis patients have a higher risk of cirrhosis or hepatic carcinoma. Acute hepatitis resolves as HBsAg clears, and anti-HBs can be detected. As infection resolves, HBeAg fades, and anti-HBe appears. In chronic hepatitis patients, HBsAg persists, and the corresponding antibody cannot be detected. Similarly, HBeAg can persist.

Question 16

What are the differences between classic dengue fever and dengue hemorrhagic fever?

Answer 16

Dengue fever (DF) is a fairly mild, self-limiting disease, with patients experiencing fever, headache, myalgia, and bone pain. Dengue hemorrhagic fever is a serious infection, and these patients develop the symptoms of classic DF, along with thrombocytopenia, hemorrhage, and shock. Death can result from the infection.

Question 17

What are the methods commonly used to diagnosis rabies?

Answer 17

One of the classic methods for the diagnosis of rabies is to detect Negri bodies, eosinophilic cytoplasmic inclusions, in neurons. However, fluorescent antibody and ELISA methods are available for the rapid detection of rabies in brain tissue and are the preferred methods.

Question 18

What is fifth disease? What is the cause of this disease?

Answer 18

Erythema infectiosum is also termed fifth disease because it is the fifth childhood viral rash after rubeola, rubella, varicella, and exanthem subitum. The causative agent of fifth disease is parvovirus B19.

Question 19

Following the administration of the vaccine for HBV, which of the following serologic markers should be positive?

a. HBeAg
b. HBcAg
c. Anti-HBs
d. Anti-HBc

Answer 19

c. Anti-HBs

Question 20

Rotavirus is most often associated with:

a. Infant diarrhea
b. Paralysis in children
c. Infant respiratory infections
d. Infectious mononucleosis– like symptoms in young adults

Answer 20

a. Infant diarrhea

Question 21

Which types of infections are caused by human papillomavirus (HPV)?

Answer 21

Many human papillomaviruses (HPVs) cause plantar, common, and genital warts. Some strains are associated with a rare autosomal disease called epidermodysplasia verruciformis, and some are associated with cervical cancer. There is now a vaccine available (Gardasil) for some of the strains associated with cervical cancer.

Question 22

Which viruses have the potential for latency?

Answer 22

The viruses most noted for latency are the herpesviruses.

Question 23

Why are vaccines for influenza not always effective?

Answer 23

Influenza viruses mutate often as a result of replication errors. These mutations cause antigenic drift, ensuring antigenic variability of strains each year. Recombination events of the influenza A genome result in a major antigenic change called antigenic shift. Health care agencies predict the most likely strains that will predominate in the next season. Trivalent influenza vaccines are available prior to the start of the influenza season. Although this process is extremely successful, occasionally an unexpected strain will predominate, and the vaccine may not provide total coverage for that strain. Even with this known possibility, it is still advised that all persons be vaccinated because some protection is better than no protection at all.

Question 24

Points to Remember

Answer 24

■ Clinical virology services can consist of simple and rapid antigen or antibody detection kits, or they can be more sophisticated, with cell culture capability and nucleic acid amplification methods.
■ Clinically significant viruses can be isolated from patients with signs and symptoms commonly thought to be associated with bacterial infections, including pneumonia, GI disorders, cutaneous lesions, sexually transmitted infections, and sepsis.
■ Members of the family Herpesviridae produce life-long latent infections.
■ Most cases of cervical cancer are linked to HPV, the causative agent of genital warts.
■ Some viruses mutate rapidly, resulting in new strains, which can be challenging to contain or treat.
■ Retroviruses (e.g., HIV) replicate with the enzyme reverse transcriptase, which uses viral RNA as a template to make a complementary DNA strand.
■ Arboviruses are those viruses transmitted by the bite of arthropods, such as mosquitoes.
■ Many emerging infections are caused by viral agents that are unexpectedly transplanted into a susceptible human population.
■ The hepatitis viruses are a diverse collection of viruses grouped together because they all infect primarily the liver. Laboratory diagnosis is based on serologic markers.
■ Antiviral compounds can treat numerous viral infections, but resistance has been seen.