What is Coronavirus?
Coronaviruses belong to a family known as Coronaviridae, and under an electron microscope they look like spiked rings. They’re named for these spikes, which form a halo or “crown” (corona is Latin for crown) around their viral envelope.
Coronaviruses contain a single strand of RNA (as opposed to DNA, which is double-stranded) within the envelope and, as a virus, can’t reproduce without getting inside living cells and hijacking their machinery. The spikes on the viral envelope help coronaviruses bind to cells, which gives them a way in, like blasting a door open with C4. Once inside, they turn the cell into a virus factory — the RNA and some enzymes use the cell’s molecular machinery to produce more viruses, which are then shipped out of the cell to infect other cells. Thus, the cycle starts anew.
Typically, these types of viruses are found in animals ranging from livestock and household pets to wildlife such as bats. Some are responsible for disease, like the common cold. When they make the jump to humans, they can cause fever, respiratory illness and inflammation in the lungs. In immunocompromised individuals, such as the elderly or those with HIV-AIDS, such viruses can cause severe respiratory illness, resulting in pneumonia and even death.
Extremely pathogenic coronaviruses were behind the diseases SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome) in the last two decades. These viruses were easily transmitted from human to human but were suspected to have passed through different animal intermediaries: SARS was traced to civet cats and MERS to dromedary camels. SARS, which showed up in the early 2000s, infected more than 8,000 people and resulted in nearly 800 deaths. MERS, which appeared in the early 2010s, infected almost 2,500 people and led to more than 850 deaths.
You’re going to be inundated with new terms and phrases you may never have heard before during this pandemic — if you’re finding yourself confused, these might help
What is COVID-19?
In the early days of the outbreak, the media, medical experts and health professionals were referring to “the coronavirus” as a catch-all term to discuss the outbreak of illness. But a coronavirus is a type of virus as we explain in the section above, rather than a disease itself.
To alleviate the confusion and streamline reporting, WHO has named the new disease COVID-19 (for coronavirus disease 2019). “Having a name matters to prevent the use of other names that can be inaccurate or stigmatizing,” said Tedros Adhanom Ghebreyesus, director-general of the WHO. “It also gives us a standard format to use for any future coronavirus outbreaks.”
The Coronavirus Study Group, part of the International Committee on Taxonomy of Viruses, was responsible for naming the novel coronavirus itself. The novel coronavirus — the one that causes the disease — is known as SARS-CoV-2. The group “formally recognizes this virus as a sister to severe acute respiratory syndrome coronaviruses (SARS-CoVs),” the species responsible for the SARS outbreak in 2002-2003.
- The novel coronavirus is officially named SARS-CoV-2.
- The disease caused by SARS-CoV-2 is officially named COVID-19.
What is a pandemic?
“Pandemic is not a word to use lightly or carelessly. It is a word that, if misused, can cause unreasonable fear, or unjustified acceptance that the fight is over, leading to unnecessary suffering and death,” said Tedros Adhanom Ghebreyesus, WHO director-general, at a press briefing.
So what is a pandemic?
Both the CDC and the WHO have different definitions, and if you look in a dictionary, you may find something different again. In the simplest terms, a pandemic can be defined as “a worldwide outbreak of a new disease.”
The “new” is key here, because many diseases persist in the population and spread each year. For example, influenza (the flu) infects a lot of people every year and can be found across the world. Unlike COVID-19, it’s been circulating in the community for many years, there’s some natural immunity to it, and we know so much about it we can protect against it.
Where did the virus come from?
The virus appears to have originated in Wuhan, a Chinese city about 650 miles south of Beijing that has a population of more than 11 million people. The Huanan Seafood Wholesale Market, which sells fish, as well as a panoply of meat from other animals, including bats, snakes and pangolins, was implicated in the spread in early January.
Prestigious medical journal The Lancet published an extensive summary of the clinical features of patients infected with the disease stretching back to Dec. 1, 2019. The very first patient identified had not been exposed to the market, suggesting the virus may have originated elsewhere and been transported to the market, where it was able to thrive or jump from human to animal and back again. Chinese authorities shut down the market on Jan. 1.
“How does the coronavirus spread?
This is one of the major questions researchers are still working hard to answer. The first infections were potentially the result of animal-to-human transmission, but confirmation that human-to-human transmission was obtained in late January. As the virus has spread, local transmission has been seen across the world. Some of the most at-risk people are those that work in healthcare.
“The major concern is hospital outbreaks, which were seen with SARS and MERS coronaviruses,” said Raina MacIntyre, a professor of global biosecurity at the University of New South Wales, Australia. “Meticulous triage and infection control is needed to prevent these outbreaks and protect health workers.”
WHO says the virus can move from person to person via:
- Respiratory droplets — when a person sneezes or coughs.
- Direct contact with infected individuals.
- Contact with contaminated surfaces and objects.
A handful of viruses, including MERS, can survive for periods in the air after being sneezed or coughed from an infected individual. Although recent reports suggest the novel coronavirus may be transmitted in this way, the Chinese Center for Diseases Control and Prevention have reiterated there is no evidence for this. Writing in The Conversation on Feb. 14, virologists Ian Mackay and Katherine Arden explain “no infectious virus has been recovered from captured air samples.”
Further research has shown SARS-CoV-2 may linger in the air for extended periods of time, which is particularly notable for health workers. It’s estimated the virus can stay suspended in the air for a period of about 30 minutes. Social distancing measures become ever more important here because only those close to infected individuals are expected to be exposed to large quantities of the virus in the air.
Why do people keep saying “flatten the curve”?
The idea of “flattening the curve” relates to the way governments and citizens can take measures to prevent a huge spike in confirmed coronavirus cases. We have a full explainer on flattening the curve and social distancing. The critical idea at the heart of the saying is to reduce the load on the health care system by taking a number of steps to limit interactions with other people. In doing so, we can stop the spread of COVID-19 and, hopefully, keep our hospitals from becoming overcrowded.
The coronavirus curve. If we intervene and implement strong social distancing measures, we can prevent the healthcare system from becoming overwhelmed.
Adapted from CDC/Drew Harris (@drewah
How long can the coronavirus survive on surfaces?
There’s still a lot to learn about the hardiness of this particular virus, but similar members of the coronavirus family have been explored in detail, including the coronaviruses responsible for the SARS and MERS outbreaks. Particularly notable is an article published on Feb. 6 in The Journal of Hospital Infection, which looked at a host of previous studies (22 in total) and found coronaviruses may persist on surfaces for up to nine days.
A study in the New England Journal of Medicine on March 17 took a deeper look at how stable the SARS-CoV-2 virus is in the air and on surfaces. There’s a chance the virus survives on cardboard for up to 24 hours, while on copper surfaces it seems to only survive for around four hours. On plastic and steel, it might survive up to 3 days.
A chief concern for the public has been whether global package shipments could help spread the virus. Different materials can keep the virus alive for longer outside the body, but a range of factors needs to be taken into account when evaluating virus survival. The CDC is still investigating this but has come up with numbers for certain surfaces.
The CDC will continue to investigate but believes the risk of contracting coronavirus from packages is still low. The WHO notes it is “very unlikely” you would see the coronavirus persist after being moved, traveled and exposed to different conditions.
Best tip? Wash your hands after handling any packages if you’re concerned (and just wash your hands, a lot, in general).
What are the symptoms?
The new coronavirus causes symptoms similar to those of previously identified disease-causing coronaviruses. In currently identified patients, there seems to be a spectrum of illness: A large number experience mild pneumonia-like symptoms, while others have a much more severe response.
According to the report, patients present with:
- Fever, elevated body temperature
- Dry cough
- Fatigue or muscle pain
- Breathing difficulties
Less common symptoms include:
- Coughing up mucus or blood
- Kidney failure
As the disease progresses, patients also come down with pneumonia, which inflames the lungs and causes them to fill with fluid. This can be detected by an X-ray.