17 - Norovirus Flashcards
About _______ NoV outbreaks occur in Canada each year
300-400
Norovirus illness can happen year-round, but outbreaks are more common in _____ and ____ months
fall
winter
The illness is easily spread in :
group settings where people are in close contact, like schools, hospitals, ect
Noroviruses are found in the _______ or _______ of infected people
stool
vomit
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
T * some people may be contagious for as long as 2-3 weeks after recovery
T or F: there’s no specific treatment available for norovirus
T
_________ is recommended and _________ may be used to treat the nausea and diarrhea on an as-needed basis
Rest
medications
Most (59%) of norovirus outbreaks occur in _____________
long-term care facilities
People can become infected with norovirus in 3 ways:
- 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
___________ like oysters may be contaminated by sewage in water, before they are harvested
shellfish
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
gastroenteritis
The main symptoms of norovirus illness are:
- 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
Symptoms generally subside after about ________
3 days
NoV characteristics:
- RNA genome
- Non-enveloped virus
- Genome 7500 bp long
- (+) ssRNA
- commonly known as the norwalk virus
Noroviruses are genetically classified into 5 different genogroups:
GI GII GIII GIV GV
Genogroup ___ is the most prevalent human genogroup which contains 19 genotypes
II
Genotypes __,__ and ___ infect humans
I
II
IV
Genotype III infects _________
bovine species
Genotype ___ infects mice
V
T or F: Because there’s so much different genotypes it is very hard to acquire immunity to NoV
T
NoV lifecycle:
- 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
In September 2016 when it was discovered that NoV could be cultured if ________ was added to enterocyte cell culture
human bile
How do you detect NoV?
- 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
