Marguerite Sprague: Coronavirus: Crowned but not royalty
The current coronavirus outbreak that began in Wuhan, China has everyone concerned. Viruses are not a simple subject: there are more than we can count, and the details get confusing quickly.
We all know people “catch” viruses, but there are also some that animals catch (e.g., Parvo virus in dogs) and still others that plants can catch (e.g., tobacco mosaic virus), and a few that have migrated from animals to people. It is at once fascinating and worrisome.
A virus — any virus — is a strand of genetic material, DNA or RNA, wrapped in a protein coat.
There are gazillions of viruses out there, with a gazillion differences, but they all have a few characteristics in common:
They’re tiny, less than 200 nanometers across. That’s 0.0002 millimeters or 0.0000078740157 inches. The head of a pin is 2 millimeters which is 10,000 times larger than a virus. Unsurprisingly, they can’t be seen with the naked eye.
They can’t replicate (reproduce themselves) outside of a host cell. That means they can’t replicate on Kleenex or toilet seats, but they can try to survive long enough to infect a host cell, where they can start replicating. Viruses have different lifespans outside of a host. Some only live a few hours, others live much longer. Some noroviruses (stomach bugs) have survived for a few weeks on hard surfaces (so clean up well!). Viruses get into host cells in different ways: by air (coughing and sneezing), via carriers such as mosquitoes, or through bodily fluids (saliva, blood or semen).
They don’t have ribosomes, cell structures that make protein for various important cellular functions.
There are families of viruses. The Wuhan virus is a coronavirus, a family of viruses that have been known since the 1960s and typically cause upper respiratory infections in people. They are named for their physical appearance: their crown-like shape comes from protein spikes that stick out of their outer coats.
In people, coronaviruses usually cause upper respiratory infections that can range from being like the common cold — annoying but rarely deadly — all the way to the current virus from Wuhan that has people concerned. Coronaviruses are “zoonotic” or transmissible from animals to people. Other recent coronaviruses include SARS-CoV, which went from civet cats to people, and MERS-CoV, which went from dromedary camels to people. Other coronaviruses that are found in animals have not as of yet infected people. This particular coronavirus that’s making all the headlines is called, for the moment, “2019 n-CoV.” It’s not a snappy name, but they try to avoid giving viruses names that people may misinterpret or find upsetting; after all, no one in our area would appreciate a “Tahoe flu” even if it originated here.
Some people wonder why antibiotics are useless against this bug. That’s because antibiotics kill bacteria, but not viruses. That’s part of what makes viruses challenging for doctors — and patients.
Experts are still trying to pinpoint the virus’s incubation period, which is how long it takes to get sick after being exposed to it. Current estimates from the CDC are from 2 to 14 days. They’d like to get a firmer picture, but that’s what’s turned up so far. The symptoms include fever, dry cough and shortness of breath, but those “flu-like” symptoms also fit the description of a number of other bugs, including common colds, so there’s no reason to panic if you turn up with them. That, and the fact that unless you’ve been visiting Wuhan City in China recently, it’s extremely unlikely that you’ve been exposed to this celebrity coronavirus.
Good hygiene is the best preventive: Wash your hands, particularly before handling food and after going to the bathroom, or coughing, sneezing or blowing your nose. A new hint is to wash them for as long as it takes you to sing the ABC song from childhood. Throw used tissues in the trash.
For more information about the Wuhan, China coronavirus, please check the U.S. Center for Disease Control website at https://www.cdc.gov/coronavirus/2019-ncov/summary.html, and the World Health Organization website at https://www.who.int/health-topics/coronavirus.
Marguerite Sprague lives in Tahoe City.