Right up until his final show
on February 6, Jay Leno was making jokes about norovirus outbreaks on cruise ships. I watched Jay often enough to know that this was a very frequent topic of his one-liners.
This made me wonder...
What is norovirus?
What makes it so successful?
And what are we able to do about it?
It’s called Winter Vomiting Bug in Britain. So, if you were to contract norovirus, you already know that it is no joke. You might experience symptoms such as cramping, nausea, vomiting, and diarrhea. And even if you started off being healthy, these symptoms could last three days. According to the Centers for Disease Control and Prevention
(CDC) there is no vaccine and there are no drugs to treat this disease.
What makes this virus successful?
I began writing down a list of rules for a successful virus. Then it occurred to me that using anthropomorphism to explain biological or chemical phenomena could be interpreted to imply design, and we already had the Bill Nye/Ken Ham debate
this past week.
So let’s instead just look at the attributes of norovirus that make it such a successful virus:
•Be annoying and debilitating without killing your host.
•Facilitate spread through air or water by causing vomiting and diarrhea.
•Continue to spread by remaining contagious for several days after host apparently feels better.
•Persist for long periods of time on surfaces at ambient temperatures, months on solid surfaces, years in water.
•But, don’t form an envelope by incorporating any host cell membrane, since a lipid-based envelope is susceptible to alcohol-type sanitizers.
“Norovirus can spread quickly from person to person in crowded, closed places like nursing homes, daycare centers, schools, hotels, and cruise ships. Noroviruses can also be a major cause of outbreaks in restaurants and catered-meal settings if contaminated food is served
We are barely into 2014 and we have already heard of 3 major cruise ship outbreaks
. Last summer, an outbreak in a Victoria B.C. seniors’ complex
made more than 150 persons ill and lead to the death of nine.
So why don’t we have a vaccine for norovirus?
Norovirus, the common cold virus, and the flu virus are all RNA viruses and they are spread by aerosol. Antibiotics have no effect on any of these.
It is virtually impossible to make a vaccine against the common cold. There are so many antigen variations that it is not feasible to make antibodies. On the other hand, the influenza vaccine is made up for 3 or 4 common and possible antigens. These are tweaked each year to anticipate what form of the flu virus will be present in the coming flu season. Flu vaccination has been so successful that there can be line-ups in flu season to get the shot.
The norovirus genome is a single strand of RNA that codes for only a few proteins: an RNA-dependent RNA polymerase, and several viral capsid proteins. Through modern biotechnology some progress towards a vaccine for norovirus has been made.
One research group has designed a vaccine with virus-like particles
to mimic the antigens of the norovirus. The initial results were promising but not sufficient
for the scientists to feel they have finished development. Another group has been working with modified tobacco-mosaic virus
producing self-assembling norovirus capsid protein. This virus protein minus the RNA may serve as an antigen in the development of a vaccine.
Finally, how exciting is this! Apparently copper alloys are effective antimicrobial surfaces
. Amazingly, brass and stainless steel have no effect. It seems that copper messes with the viral genome, thus reducing the infectivity of norovirus. Is it possible that in the future cruise ships, seniors’ centres and even schools will have more copper features to reduce the spread of infectious diseases, including norovirus?
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