What is the corona virus?
Corona viruses are a family of hundreds of viruses that can cause fever, respiratory problems, and sometimes gastrointestinal symptoms too. The 2019 novel corona virus is one of seven members of this family known to infect humans, and the third in the past three decades to jump from animals to humans. Since emerging in China in December, this new corona virus has caused a global health emergency.
How does it spread?
It’s likely to be transmitted in droplets from coughing or sneezes, and the virus has a two- to 14-day incubation period. That means people could be infectious for quite a while before symptoms like fever, cough, or shortness of breath emerge.
What are the particular symptoms of Covid-19?
In the confirmed cases so far, most people get a fever with a dry cough; smaller numbers of folks might experience shortness of breath, a sore throat, or a headache.
How can I avoid catching the corona virus?
- Wash your hands wash your hands wash your hands wash your hands wash your hands wash your hands wash your hands wash your hands wash your hands wash your hands wash your hands wash your hands wash your hands. You get the point.
- Clean all of your tech equipment. Just like your hands, your smartphone and keyboard and headphones and anything else gets germs on it.
- Are you a health care worker? If not, don’t buy a face mask—that depletes supplies for the health professionals who need them. Same goes for gloves (see: “wash your hands,” above).
- If you’re in a high-risk group (over 60, have preexisting lung disease, heart disease, diabetes, or a weakened immune system) you should seek treatment if you get sick, since it can quickly go from cough to full-blown pneumonia. Call your doctor or clinic first with your suspicions so they can direct you appropriately. If you’re not in a high-risk group, better to self-isolate at home with plenty of fluids and anti-fever med. Odds are you’ll recover, and this way you won’t expose anyone. Still call your doctor, so they know what’s going on—they may be able to direct you to people at the health department who can conduct testing. Don’t go to the ER unless you’re really experiencing life-threatening symptoms.
Q: Is Covid-19 more deadly than the flu?
That remains to be seen. According to preliminary estimates from the Centers for Disease Control and Prevention, the 2019–2020 flu caused 19 million to 25 million illnesses and up to 25,000 deaths. The Covid-19 numbers are harder to calculate because it’s not yet clear how many people are infected. The CDC calculates the death rate at about 2 percent, which is higher than the flu—but the real number might be a lot lower, because less-severe cases may not have been reported. People with more mild cases might not even go to the hospital, and health care workers might have mistaken cases for the flu or for pneumonia. If epidemiologists count only the most severe cases, the death rate will look higher because a higher proportion of those patients die—so that might not offer an accurate reflection of reality.
How do corona viruses even work?
Corona viruses are divided into four groups called genera: alpha, beta, gamma, and delta. These little invaders are zoophytic, meaning they can spread between animals and humans; gamma and delta corona viruses mostly infect birds, while alpha and beta mostly reside in mammals.
Researchers first isolated human corona viruses in the 1960s, and for a long time they were considered pretty mild. Mostly, if you got a corona virus, you’d end up with a cold. But the most famous corona viruses are the ones that jumped from animals to humans.
Corona viruses are made up of one strip of RNA, and that genetic material is surrounded by a membrane studded with little spike proteins. (Under a microscope, those proteins stick up in a ring around the top of the virus, giving it its name—“corona” is Latin for “crown.”) When the virus gets into the body, those spike proteins attach to host cells, and the virus injects that RNA into the cell’s nucleus, hijacking the replication machinery there to make more virus. Infection ensues.
The severity of that infection depends on a couple of factors. One is what part of the body the virus tends to latch onto. Less serious types of corona virus, like the ones that cause the common cold, tend to attach to cells higher up in the respiratory tract—places like your nose or throat. But their more gnarly relatives attach in the lungs and bronchial tubes, causing more serious infections. The MERS virus, for example, binds to a protein found in the lower respiratory tract and the gastrointestinal tract, so that, in addition to causing respiratory problems, the virus often causes kidney failure.
The other thing that contributes to the severity of the infection is the proteins the virus produces. Different genes mean different proteins; more virulent corona viruses may have spike proteins that are better at latching onto human cells. Some corona viruses produce proteins that can fend off the immune system, and when patients have to mount even larger immune responses, they get sicker.
What is this new corona virus, and where did it come from?
Corona viruses are a large family of viruses that typically attack the respiratory system. The name comes from the Latin word corona, for crown,and the ancient Greek korōnè, meaning garland or wreath, because of the spiky fringe encircling these viruses. Most corona viruses infect animals, such as bats, cats, and birds. Only seven, including Covid-19, SARS, and MERS, are known to infect humans.
SARS is thought to have evolved from infecting bats to civet cats to humans in China; MERS evolved from bats to camels to humans in the Middle East. No one knows precisely where Covid-19 came from, though a leading hypothesis is that bats were once again the original source: They spread the virus to another animal species, possibly a paneling, where it jumped to humans.
2) What are the symptoms and death rate?
Two of the seven corona viruses that infect humans, SARS and MERS, can cause severe pneumonia and even death in 10 and more than 30 percent of cases, respectively. But others lead to milder symptoms, like a common cold. The most common symptoms of Covid-19 are fever and dry cough.
No one knows the precise incubation period for the virus, but symptoms can show up anywhere from one day to two weeks after exposure, according to a WHO report on China’s response.
At the moment, we know Covid-19 can cause pneumonia and that it too can kill — but while it seems to be less deadly than SARS and MERS, it’s not yet clear by precisely how much.
Some of the best evidence on the question comes from a February 16 China Center for Disease Control report looking at the outcomes of the first 72,314 patients with confirmed or suspected Covid-19 in mainland China. It’s the largest such analysis to date, and it found an overall case fatality rate of 2.3 percent — lower than both SARS and MERS. (The case fatality rate, or CFR, is the proportion of deaths a disease causes within a group of people who have the disease.)
The researchers also discovered a huge variation in the case fatality rate by age group. In short, the virus appears to be deadlier in people with each passing decade. You can see the trend in this graph:
What should I do if I think I have Covid-19?
If you’re in a high-risk group — over the age of 60 with an underlying health condition — seek medical treatment immediately, and let your hospital or health care provider know you suspect Covid-19 before showing up.
Otherwise, stay at home and call a health professional, Vows Um air Iran explained: “They will work with your local health department and figure out whether you need to get tested or get treatment. Doctors and health officials advise not to go to the emergency room if your symptoms do not appear to be life-threatening.” There’s a good chance you’ll recover with nothing more than rest and fluids. But you will need to self-isolate while sick to avoid spreading the disease to others, including any people in your home. Here’s how to do it.
The CDC and the WHO recommend several basic measures to help prevent the spread of Covid-19:
- Wash your hands often for at least 20 seconds.
- Cover your cough or sneeze with a tissue, then throw the tissue in the trash.
- Clean and disinfect frequently touched objects.
- Stay home when you are sick.
- Contact a health worker if you have symptoms; fever and a dry cough are most common.
- DON’T touch your face.
- DON’T travel if you have a fever and cough.
- DON’T wear a face mask if you are well.
4) How do corona-viruses spread?
We don’t yet know exactly how SARS-CoV-2 — the virus that causes the Covid-19 disease — spreads, but we do have a lot of data on how MERS, SARS, and other respiratory viruses move from person to person. And that’s mainly through exposure to droplets from coughing or sneezing.
How does the new corona virus spread? These new studies offer clues.
So when an infected person coughs or sneezes, they let out a spray, and if these droplets reach the nose, eyes, or mouth of another person, they can pass on the virus, said Jennifer Nuzzle, an infectious disease expert and senior scholar at the Johns Hopkins Center for Health Security. In rarer cases, a person might catch a respiratory disease indirectly, “via touching droplets on surfaces — and then touching mucous membranes” in the mouth, eyes, and nose, she added.
There’s also emerging evidence showing that SARS-CoV-2 may spread through poop — known as the “fecal-oral” route of disease transmission. Researchers are on the lookout for potential airborne transmission, too, and there’s a lot of speculation about whether inanimate objects — like door handles — can pass on the virus.
In the case of airborne transmission, a person would get infected by directly inhaling droplets suspended in the air from an infected individual. With “mites” — objects that can transmit infections — droplets from an infected person would end up on surfaces another person touches. “So far, there is no conclusive evidence of that,” wrote Megan Murray, a Harvard Infectious Disease specialist, in a corona virus explainer, “although that is challenging to prove one way or the other.”
What we do know: More and more research is piling up to suggest people who have only mild symptoms, or no symptoms at all, can test positive for Covid-19 disease. The virus also appears to be present in the body at very high levels early on in an illness, when people are still going to work or traveling.