MLT GlobeVirology: Herpesviruses – page 2
36 Virology MCQs on Herpesviruses with answers and explanations.
Ganciclovir is a guanosine analogue used for CMV disease. Which drug is it structurally closest to?
Ganciclovir differs from acyclovir by one hydroxymethyl group; both need phosphorylation, by UL97 kinase for ganciclovir in CMV. Vidarabine is an adenosine analogue.
Kaposi sarcoma in a person with advanced HIV disease is caused by which virus?
HHV-8 (Kaposi sarcoma-associated herpesvirus) causes Kaposi sarcoma, primary effusion lymphoma and multicentric Castleman disease, mostly in immunosuppressed patients.
Epstein-Barr virus persists for life after infectious mononucleosis. In which cells is it latent?
EBV enters B cells via CD21 and remains latent in memory B cells; this underlies its role in B-cell lymphomas. HSV and VZV are latent in sensory ganglia.
A teenager has fever, fatigue and atypical lymphocytes, but the heterophil test and EBV serology are negative. Which virus is the most common cause?
CMV is the leading cause of heterophil-negative mononucleosis; confirmation is by CMV IgM with low IgG avidity or PCR. Toxoplasma and acute HIV are also considered.
Endemic Burkitt lymphoma in African children, with a t(8;14) MYC translocation, is associated with which virus?
Nearly all endemic Burkitt lymphomas carry EBV, with malaria as a co-factor; high antibody to EBV early antigen (restricted pattern) is characteristic.
In southern China, screening for nasopharyngeal carcinoma uses serum IgA against which virus antigen (VCA/EBNA1)?
Undifferentiated nasopharyngeal carcinoma is EBV-associated; IgA anti-VCA/EBNA1 and plasma EBV DNA are used for screening and monitoring.
A newborn has limb hypoplasia, zig-zag skin scarring and eye defects after maternal infection at 15 weeks' gestation. Which virus is responsible?
Congenital varicella syndrome follows maternal chickenpox in the first half of pregnancy, with cicatricial skin lesions and limb hypoplasia. Neonatal HSV is usually acquired at delivery.
A kidney transplant recipient is monitored for cytomegalovirus reactivation. Which specimen is used for quantitative CMV PCR?
CMV viral load in plasma or whole blood guides pre-emptive therapy in transplant recipients. Urine or saliva is used instead for congenital CMV in newborns.
Which patient poses the greatest risk of spreading CMV to hospital staff?
Infants with congenital CMV shed large amounts of virus in urine and saliva for months, so standard precautions and hand hygiene are important.
A Tzanck smear from a vesicle shows multinucleated giant cells. Which statement is correct?
HSV-1, HSV-2 and VZV all produce multinucleated giant cells with nuclear molding. PCR or specific antigen tests are needed to identify the virus.
A 3-year-old has fever, pharyngitis and atypical lymphocytes, but the heterophile antibody test is negative. Which test is best next?
Young children often do not make heterophile antibodies during EBV infection. EBV-specific VCA IgM shows acute infection.
EBV serology shows VCA IgG positive, VCA IgM negative and EBNA IgG positive. This indicates:
Antibody to EBNA appears weeks to months after infection and persists for life. With negative VCA IgM, the pattern shows past infection.
Which laboratory method is most sensitive for confirming varicella-zoster virus in a vesicular skin lesion?
PCR of vesicle material is the most sensitive and specific test and distinguishes VZV from HSV. VZV is labile and grows poorly in culture, and the Tzanck smear cannot tell VZV from HSV.
Human herpesvirus 4 (HHV-4) is the formal name of:
HHV-1 and 2 are HSV, HHV-3 is VZV, HHV-4 is EBV and HHV-5 is CMV.
To prevent transfusion-transmitted cytomegalovirus in a low-birth-weight neonate, the blood bank supplies red cells that are:
CMV is carried in white cells, so CMV-negative or leucoreduced components reduce transmission; irradiation prevents graft-versus-host disease, not CMV.
In the shell vial culture method for CMV, the virus is detected within 24–48 hours by:
Centrifugation enhances infection of cells on a coverslip, and fluorescent antibodies detect early antigen before cytopathic effect appears. Conventional CMV culture may take up to 3 weeks.