MLT GlobeVirology: Enteric & other viruses
63 Virology MCQs on Enteric & other viruses with answers and explanations.
Enteroviruses cause all of these conditions EXCEPT one. Which condition is NOT an enteroviral disease?
Post-infectious glomerulonephritis follows group A streptococcal infection. Enteroviruses cause aseptic meningitis, paralysis (polio) and pleurodynia (coxsackie B).
Which statement about poliovirus is INCORRECT?
Both inactivated (IPV, Salk) and oral live attenuated (OPV, Sabin) polio vaccines exist. Most infections are subclinical, and virus is shed in throat and stool.
Picornaviruses cause many diseases. Which of these is NOT caused by a picornavirus?
Infectious mononucleosis is caused by EBV, a herpesvirus. HAV (a hepatovirus) and enteroviruses (herpangina, myocarditis) are picornaviruses.
Which virus is NOT a member of the family Picornaviridae?
Rabies virus is an enveloped, bullet-shaped rhabdovirus. Coxsackie, echo, polio and rhinoviruses are small naked picornaviruses.
A young man has sudden sharp chest pain worse on breathing (Bornholm disease) and later develops myocarditis. Which virus is most likely?
Group B coxsackieviruses cause epidemic pleurodynia (Bornholm disease), myocarditis and pericarditis. Group A strains cause herpangina and hand-foot-mouth disease.
An outbreak of vomiting and diarrhoea on a cruise ship spreads rapidly. Which virus (formerly Norwalk virus) is the most likely cause?
Noroviruses, first identified as Norwalk virus, are the leading cause of gastroenteritis outbreaks in closed settings; they have a low infectious dose and resist many disinfectants.
Which virus has a genome of segmented double-stranded RNA?
Rotavirus carries 11 dsRNA segments within a triple-layered capsid. Parvovirus is ssDNA; HAV and rubella are non-segmented ssRNA.
What kind of genome does poliovirus carry?
Poliovirus, a picornavirus, has +ssRNA that acts directly as mRNA and is translated into one polyprotein.
A child with sickle cell disease suddenly becomes profoundly anaemic with near-zero reticulocytes after a mild febrile rash illness. Which virus is responsible?
Parvovirus B19 infects erythroid progenitors, briefly halting red cell production. Healthy children get fifth disease, but patients with shortened red cell survival develop transient aplastic crisis.
Echoviruses were named "enteric cytopathic human orphan" viruses. Which site do they primarily infect?
Echoviruses are enteroviruses that replicate in the gut and are shed in feces, though they can spread to cause meningitis or rash.
Bovine spongiform encephalopathy and sheep scrapie are caused by which kind of agent?
Prions are misfolded host PrP proteins that convert normal PrP, causing spongiform brain degeneration. BSE in cattle is linked to variant CJD in humans.
Which virus is spread mainly by the fecal-oral route rather than by an arthropod?
Coxsackieviruses are enteroviruses shed in stool. Dengue and yellow fever are mosquito-borne, and Colorado tick fever is tick-borne.
Before vaccination became widespread, which virus was the leading cause of severe dehydrating diarrhoea in children under 5?
Rotavirus is the classic cause of severe infant gastroenteritis worldwide; rotavirus vaccines have greatly reduced hospitalisations. Rhinovirus is acid-labile and respiratory.
A 6-year-old has bright red cheeks followed by a lacy rash on the limbs, and feels well. Which virus causes this fifth disease?
Erythema infectiosum ("slapped cheek") is caused by parvovirus B19; the rash appears as the child becomes non-infectious.
The name "reovirus" is an acronym. What does it stand for?
Reoviruses were isolated from respiratory and enteric tracts but not linked to any disease, hence "orphan".
Which virus causes German measles, a mild rash illness dangerous mainly in early pregnancy?
German measles is rubella; infection in the first trimester can cause congenital rubella syndrome. "Measles" proper (rubeola) is a morbillivirus.
Human papillomavirus types 6 and 11 are the usual cause of which lesion?
Low-risk HPV 6 and 11 cause genital warts; high-risk types 16 and 18 cause cervical and other anogenital cancers. HCC is linked to HBV/HCV.
What is the main clinical effect of astrovirus infection in young children?
Astroviruses infect intestinal epithelium, causing watery diarrhoea, usually milder than rotavirus, sometimes with vomiting.
Common warts are unsightly, and some related types cause cervical cancer. Which virus group is responsible?
HPV types cause skin warts (e.g. 1, 2, 4), genital warts (6, 11) and cervical cancer (16, 18 and other high-risk types).
For detecting high-risk human papillomavirus in cervical screening, which specimen is used?
HPV infects cervical epithelium; testing uses cervical cells in liquid-based cytology medium or biopsy tissue. HPV does not circulate in blood.