A magnified image of the coronavirus

Covid-19 has spread to every continent on Earth other than Antarctica.

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STANDARDS

NGSS: Core Idea: LS1.A

CCSS: Literacy in Science: 8

TEKS: 6.12D, 7.3B, 8.2E, B.3E, B.4C

Understanding a New Virus

Answers to your pressing questions about the novel coronavirus

AS YOU READ, THINK ABOUT the challenges a population faces when confronted with a new disease.

JIM MCMAHON/MAPMAN®

Last December, people in Wuhan, China, began suffering from a mysterious flu-like illness. Doctors studying them discovered that the patients had contracted a previously unknown virus—a nonliving particle that invades and reproduces in a living cell. Within two months, the disease, now called COVID-19, had reportedly infected more than 75,000 people in China and killed more than 2,000.

The symptoms of COVID-19 include fever, muscle aches, sore throat, dry cough, and shortness of breath. It spreads when a sick person coughs or sneezes, expelling tiny droplets that contain the virus. These airborne particles can enter the mouths and noses of people up to 1.8 meters (6 feet) away. Touching surfaces covered with the droplets and then your face without washing your hands can also cause you to become infected.

Last December, a mysterious illness appeared in Wuhan, China. People began suffering from flu-like symptoms. Doctors studied them and found that the patients had contracted a previously unknown virus. That’s a nonliving particle that invades and reproduces in a living cell. The disease is now called COVID-19. Within two months, it had infected more than 75,000 people in China. More than 2,000 of them died.

The symptoms of COVID-19 include fever, muscle aches, sore throat, dry cough, and shortness of breath. When sick people cough or sneeze, they spray tiny droplets that contain the virus. That’s how it spreads. These airborne particles can enter the mouths and noses of people up to 1.8 meters (6 feet) away. The droplets also land on surfaces. People could touch them and then touch their face without washing their hands. That’s another way to become infected.

ZSOLT CZEGLEDI/AP PHOTO

SCREENING FOR SYMPTOMS: Airport staff in Hungary check the temperature of people returning to the country.

Most people who catch COVID-19 suffer mild symptoms. Children, in particular, seem to be less affected by the disease. But about one in six people with COVID-19 end up becoming extremely ill. In those instances, the infection can lead to life-threatening complications like pneumonia—a buildup of fluid in the lungs. Most severe cases, and resulting deaths, occur in elderly people and those with other serious health conditions or weakened immune systems that are unable to fight off the infection.

In response to the outbreak, China quarantined millions of healthy citizens, preventing them from leaving their homes, to stop the disease from spreading. Countries also restricted people from flying into or out of China. “Governments reacted the way they did partially because it’s a new disease,” says Kurt Williamson, a virologist who studies viruses at the College of William & Mary, in Virginia.

Despite these precautions, COVID-19 spread around the globe. At the time this issue went to press, nearly 890,000 cases of COVID-19 had been reported in 203 countries, resulting in over 44,000 deaths. “Everyone needs to take this seriously and do their part,” says Williamson. “Even if you are healthy and feel fine, you should be limiting your interactions with others through social distancing.” That means avoiding places where large numbers of people gather and increasing the amount of physical space between people to avoid spreading an illness. It’s also important to wash your hands and disinfect frequently-touched surfaces, like doorknobs and railings, much more often than you normally would. Here’s what you need to know about COVID-19.

COVID-19 causes mild symptoms in most people. And children seem less affected by the disease. But about one in six people with COVID-19 becomes extremely ill. In those cases, the infection can lead to dangerous problems like pneumonia. That’s a buildup of fluid in the lungs. Most severe cases and deaths occur in elderly people and those with serious health conditions. Some have weakened immune systems, so they can’t fight off the infection.

Because of the outbreak, China quarantined millions of healthy citizens. They weren’t allowed to leave their homes. This was to stop the disease from spreading. Countries also stopped people from flying into or out of China. “Governments reacted the way they did partially because it’s a new disease,” says Kurt Williamson. He’s a virologist who studies viruses at the College of William & Mary, in Virginia.

But COVID-19 still spread around the globe. At press time, nearly 890,000 cases of COVID-19 had been reported in 203 countries. The virus had caused more than 44,000 deaths. “Everyone needs to be taking this seriously and doing their part,” says Williamson. “Even if you are healthy and feel fine, you should be limiting your interactions with others through social distancing.” That means avoiding places with large numbers of people and leaving more physical space between people. This could keep an illness from spreading. Other actions are also important. Wash your hands and disinfect commonly touched surfaces, including doorknobs and railings. Do this much more often than you normally would. Here’s what you need to know about COVID-19.

MERLIN TUTTLE/SCIENCE SOURCE

Scientists think the new virus originated in bats and spread to humans.

WHERE DID THE VIRUS THAT CAUSES COVID-19 COME FROM?

WHERE DID THE VIRUS THAT CAUSES COVID-19 COME FROM?

COVID-19 is caused by a coronavirus. This family of viruses is responsible for diseases ranging from the common cold to more serious respiratory illnesses, including two diseases you may have heard of called SARS and MERS. Coronaviruses are zoonotic, which means they originate in animals. It’s actually not uncommon for diseases to spread from animals to humans. In fact, several viruses that cause the flu came from pigs and birds. People can catch these viruses if they have direct contact with or consume an infected animal. The virus can then mutate, or change, to spread from person to person.

The first cases of COVID-19 seem to have originated in a live animal market in Wuhan. Since the virus’s discovery in humans late last year, researchers have been studying its genome. Results indicate that the virus’s hereditary material is similar to coronaviruses that came from bats. Interestingly, while these flying mammals might carry the disease, they don’t show signs of illness. “Bats don’t get sick like we do, so they can coexist with many different viruses,” says Williamson.

COVID-19 is caused by a coronavirus. This family of viruses causes many diseases. They include the common cold and more serious respiratory illnesses. You may have heard of two of them, called SARS and MERS. Coronaviruses are zoonotic, meaning they start in animals. It’s not uncommon for diseases to spread from animals to humans. In fact, several flu viruses came from pigs and birds. People might eat or have direct contact with an infected animal. Then they can catch these viruses. After that, the virus can mutate, or change, to spread from person to person.

The first cases of COVID-19 seem to have started in a live animal market in Wuhan. The virus was discovered in humans late last year. Since then, researchers have been studying its genome. Results show that the virus’s hereditary material is like that of coronaviruses from bats. Even though these flying mammals might carry the disease, they don’t show signs of illness. “Bats don’t get sick like we do, so they can coexist with many different viruses,” says Williamson.

DAVID PAUL MORRIS/BLOOMBERG VIA GETTY IMAGES

VIRUS TEST: Medical professionals in San Francisco collect samples from patients at a drive-through testing clinic.

HOW HAVE SCIENTISTS BEEN TRACKING THE SPREAD OF THE VIRUS?

HOW HAVE SCIENTISTS BEEN TRACKING THE SPREAD OF THE VIRUS?

To figure out how a virus like the one that causes COVID-19 spreads, public health scientists called epidemiologists study patterns of infection. For instance, when a patient is diagnosed with COVID-19, an epidemiologist will ask who the patient was in contact with in the 14 days prior to symptoms appearing. This process, called contact tracing, allows doctors to track down others who might be infected.

Early identification of people who’ve contracted the virus is important. If a person knows they have the virus, they can isolate themselves at home away from others. That can prevent new COVID-19 cases and eventually halt the virus’s spread.

Those infected with COVID-19 can be contagious for up to two weeks before showing signs of being ill. That’s why the Centers for Disease Control and Prevention recommended social distancing, where everyone—sick or not— avoids close contact with others. Many state and local governments also advised people to stay home from work, closed schools and businesses, and asked people to avoid large gatherings. Some hard-hit areas took additional steps like sanitizing public spaces, including subways, trains, and buses.

Public health scientists called epidemiologists try to learn how a virus like the one behind COVID-19 spreads. So they study patterns of infection. For example, when a patient is diagnosed with COVID-19, an epidemiologist asks a question. Whom was the patient around in the 14 days before symptoms appeared? This process is called contact tracing. It allows doctors to find others who might be infected.

If people have contracted the virus, it’s important to find out early. If they know they have it, they can isolate themselves at home away from others. That can prevent new COVID-19 cases. Over time, this can stop the virus’s spread.

People can be infected with the new coronavirus and show no signs for up to two weeks. But they can still be contagious. That’s why the Centers for Disease Control and Prevention recommended social distancing. The organization asked everyone, sick or not, to avoid close contact with others. Many state and local governments told people to stay home from work. They also closed schools and businesses and asked people to avoid large gatherings. Some hard-hit areas took even more steps. They disinfected public spaces, including subways, trains, and buses.

MIKE STEWART/AP PHOTO

HOME STUDY: Many schools across the world, including in the U.S., closed, forcing students to learn from home.

ARE THERE TREATMENTS FOR COVID-19?

ARE THERE TREATMENTS FOR COVID-19?

Scientists are working on a vaccine to prevent people from contracting COVID-19. A vaccine is a preventive measure that trains people’s immune systems to recognize a specific virus. If a vaccinated person is then exposed to the same virus later on, their body would be able to fight off the infection. But it will likely take at least a year until a COVID-19 vaccine is deemed safe and ready for the public, says Williamson. And because of how fast viruses mutate, scientists might need to develop new vaccines for COVID-19 each year, as they do for flu vaccines.

In the meantime, scientists are also searching for antivirals that could help treat patients with COVID-19. These medications inhibit viruses’ ability to function so they can no longer infect cells.

Scientists are working on a vaccine. It would prevent people from contracting COVID-19. A vaccine prevents infection by training people’s immune systems to recognize a certain virus. Later, vaccinated people might come across the same virus. But their bodies could fight off the infection. A COVID-19 vaccine must be considered safe and ready for the public. But that will likely take at least a year, says Williamson. And because viruses mutate so fast, scientists might need to develop new vaccines for COVID-19 each year. That’s what they do for flu vaccines.

At the same time, scientists are searching for antivirals to help treat patients with COVID-19. These medications keep viruses from functioning normally. Then they can’t infect more cells.

HOW CAN I REDUCE MY RISK OF GETTING SICK?

HOW CAN I REDUCE MY RISK OF GETTING SICK?

Since there’s currently no vaccine or medication to treat COVID-19, the best defense against the virus is everyday preventive behaviors. Along with social distancing, it’s important to wash your hands more frequently than usual.

Each of the virus particles that cause COVID-19 are surrounded by an envelope, or outer layer, made up of fats. Soap breaks apart this membrane, destroying the virus. That’s why thorough handwashing is one of the best ways to halt the virus in its tracks. It doesn’t matter if you wash your hands in warm or cold water, as long as you lather them up well and scrub all over for at least 20 seconds (see Healthy Handwashing). That’s about the amount of time it would take to sing “Happy Birthday” twice.

For now, it’s hard to know if the virus will disappear once the outbreak ends or whether it will reappear each year, in a way that’s similar to the seasonal flu, says Williamson. Even though that may sound scary, experts say it’s important to stay calm and do what’s necessary to protect one another.

Right now, there’s no vaccine for COVID-19 or medication to treat it. So the best defense against the virus is everyday preventive actions. Social distancing is important. So is washing your hands more often than usual.

An envelope, or outer layer, surrounds each of the virus particles that cause COVID-19. This membrane is made up of fats. Soap breaks it apart and destroys the virus. That’s why good handwashing is one of the best ways to stop the virus. It doesn’t matter if you wash your hands in warm or cold water. Just lather them up well and scrub all over for at least 20 seconds (see Healthy Handwashing). That’s about how long it would take to sing “Happy Birthday” twice.

Will the virus disappear when the outbreak ends? Or will it come back each year, like the seasonal flu? For now, it’s hard to know, says Williamson. That may sound scary. But experts say it’s important to stay calm and do what’s needed to protect one another.

COMMUNICATING INFORMATION: Use what you learned from the article to create a poster explaining how to lower your risk of catching COVID-19.

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