Norovirus (28) Flashcards
What is correct about viral gastroenteritis?
a. 15% of infectious diarrhoea is caused by viruses
b. All viruses found in the gut cause gastroenteritis
c. Rotavirus and coronavirus cause systemic and invasive infections
d. It is a major killer or undernourished children in developing countries
d. It is a major killer or undernourished children in developing countries
What is NOT a feature of norovirus?
a. It is a small calicivirus
b. It is responsible for 20% of gastroenteritis cases
c. It can survive stomach acid due to its capsid protein and hardy envelope
d. It can infect humans, like Sapovirus
c. It can survive stomach acid due to its capsid protein and hardy envelope
What is a feature of the epidemiology of norovirus?
a. Pandemics are rare in developed countries
b. It causes 1-2million deaths in Australia each year
c. Most people are seropositive by 4 years of age
d. Transmission occurs from fomites only
c. Most people are seropositive by 4 years of age
Pandemic norovirus:
a. Is often causes by norovirus genotype GI.6
b. Often results from recombination at ORF1/2 overlap, ORF2/3 overlap or within ORF2 where the capsid is encoded
c. Can only be spread amongst children younger than 4years as most adults are already seropositive
d. Is rarely causes by recombination events
b. Often results from recombination at ORF1/2 overlap, ORF2/3 overlap or within ORF2 where the capsid is encoded
How is norovirus considered a class B bioterrorism agent?
a. It is very contagious
b. It has a long incubation period and large infectious dose
c. It is unstable in the environment
d. Illness is short lasting
a. It is very contagious
How can norovirus be transmitted via food?
a. Secondary transmission via contaminated foods before harvest
b. Primary transmission in the form of infected food handler
c. Secondary transmission during processing, storage or distribution
d. Primary transmission due to contaminated kitchen equipment
c. Secondary transmission during processing, storage or distribution
In order to detect human norovirus:
a. The virus is usually cultured in macrophages
b. Environmental swabs of food are the gold standard for detection
c. RT-PCR cannot be used as it is a DNA virus
d. Serology can be used to aid epidemiological studies
d. Serology can be used to aid epidemiological studies
Where does mouse norovirus replicate?
a. In dendritic cells and macrophages
b. Within granulocytes
c. In B lymphocytes
d. Within M cells, Goblet cells and Peyer’s patches
a. In dendritic cells and macrophages
What is NOT a feature of the MNV genome?
a. It is 7.5kb of ssRNA
b. ORF1 encodes non-structural proteins (NS6, NS7) that localise with the replication complex
c. A host protease is used to process the polyprotein into individual NS proteins
d. ORF encodes a virulence factor (VF1)
c. A host protease is used to process the polyprotein into individual NS proteins
What is true about the innate immune response to MNV?
a. The dsRNA intermediate can interact with MDA5 or RIG1
b. Cells deficient in MDA5 will not produce cytokines in response to MNV
c. Stat-1 aids the immune response, but is not required to control infection
d. MNV cannot be contained by IFN-λ
b. Cells deficient in MDA5 will not produce cytokines in response to MNV
How can MNV interact with Peyer’s Patches and other regions of the intestine?
a. It can cause Paneth cell dysfunction which can result in IBD like Crohn’s Disease
b. It passes through Peyer’s patches by transcytosis in order to cross the intestinal epithelium
c. Like poliovirus, MNV causes apoptosis of peyer’s patches and M cells
d. MNV causes vomiting by inhibiting ion channels in peyer’s patches
a. It can cause Paneth cell dysfunction which can result in IBD like Crohn’s Disease
• Most viral infections in the GIT are acute infections.
T
• Individuals infected with norovirus secrete the virus 4-6 weeks after infection.
T
• Antiperistalsis agents are the preferred treatment method for norovirus infection.
F
• Most of what we know about human norovirus has been discovered by culturing the virus under laboratory conditions.
F
