17 - Norovirus

Question 1

About _______ NoV outbreaks occur in Canada each year

Answer 1

300-400

Question 2

Norovirus illness can happen year-round, but outbreaks are more common in _____ and ____ months

Answer 2

fall

winter

Question 3

The illness is easily spread in :

Answer 3

group settings where people are in close contact, like schools, hospitals, ect

Question 4

Noroviruses are found in the _______ or _______ of infected people

Answer 4

stool

vomit

Question 5

T or F: People infected with norovirus can be contagious from the moment they start feeling ill to at least 3 days after they have recovered

Answer 5

T * some people may be contagious for as long as 2-3 weeks after recovery

Question 6

T or F: there’s no specific treatment available for norovirus

Answer 6

T

Question 7

_________ is recommended and _________ may be used to treat the nausea and diarrhea on an as-needed basis

Answer 7

Rest

medications

Question 8

Most (59%) of norovirus outbreaks occur in _____________

Answer 8

long-term care facilities

Question 9

People can become infected with norovirus in 3 ways:

Answer 9

• through direct contact with another infected person
• by touching a surface or objects contaminated with norovirus
• by eating food or drinking water that has been contaminated with norovirus

Question 10

___________ like oysters may be contaminated by sewage in water, before they are harvested

Answer 10

shellfish

Question 11

NoV usually causes symptoms of _______________ within 24-48 hours, but symptoms can start as early as 12 hours after exposure. The illness often begins suddenly

Answer 11

gastroenteritis

Question 12

The main symptoms of norovirus illness are:

Answer 12

• diarrhea
• vomiting (children usually experience more vomiting than adults)
• nausea
• stomach cramps

other less common symptoms include:

• low-grade fever
• headache
• chills
• muscle aches
• fatigue

Question 13

Symptoms generally subside after about ________

Answer 13

3 days

Question 14

NoV characteristics:

Answer 14

• RNA genome
• Non-enveloped virus
• Genome 7500 bp long
• (+) ssRNA
• commonly known as the norwalk virus

Question 15

Noroviruses are genetically classified into 5 different genogroups:

Answer 15

GI
GII
GIII
GIV
GV

Question 16

Genogroup ___ is the most prevalent human genogroup which contains 19 genotypes

Answer 16

II

Question 17

Genotypes __,__ and ___ infect humans

Answer 17

I
II
IV

Question 18

Genotype III infects _________

Answer 18

bovine species

Question 19

Genotype ___ infects mice

Answer 19

V

Question 20

T or F: Because there’s so much different genotypes it is very hard to acquire immunity to NoV

Answer 20

T

Question 21

NoV lifecycle:

Answer 21

• virus binds to the cell via carbohydrate attachment factor binding and other unknown protein receptor
• sends signals to the cell once bound
• enters the cell
• uncoating of the (+) RNA occurs
• RNA (+) is ready for translation
• viral proteins are translated and assembled into the capsid
• polyprocessing proteins start initiation of (-) RNA
• (-) RNA can make more (+) RNA
• (+) RNA is loaded into the capsids and the virus is released when lysis of the infected cell occurs

Question 22

In September 2016 when it was discovered that NoV could be cultured if ________ was added to enterocyte cell culture

Answer 22

human bile

Question 23

How do you detect NoV?

Answer 23

• Like HAV, samples to be tested for NoV are suspended in buffer and the NoV is washed into the buffer
• Various protocols such as PCR or RT-qPCR are then used to detect the presence of NoV
• Newer WGS methods are now becoming available (like extracting WGS from meta-genomic data