How the spiky coronavirus attacks your cells and makes them into little virus factories – Houston Chronicle

Coronavirus, novel coronavirus, COVID-19. Theres a lot of information and misinformation around the new virus thats affecting all corners of the world. Its tricky to understand why its so devastating without understanding how it attacks the human body. So were going to explain it.

First off, why does this affliction have so many names?

Lets start with the term coronavirus. Think of that as a family name. Some members of the coronavirus family are commonly spread among people and can cause more mild illnesses, like the common cold. Other coronaviruses infect animals. And sometimes, though its rare, coronaviruses that infect animals evolve and then infect people. This is what is suspected to have happened with the SARS-CoV-2 coronavirus, according to the Centers for Disease Control and Prevention.

COVID-19 is the name of the disease caused by this new, or novel, coronavirus, which was first identified in Wuhan, China, in December.

Now, back to the family of coronaviruses. They all have one important thing in common: crown-like spikes on their surface.

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Why should I care that the virus has spikes?

This is key to how it infiltrates the body.

When people infected with the new coronavirus cough, sneeze or simply speak, they send respiratory droplets into the air. People nearby, within roughly six feet (hence the signs in grocery stores), can inhale those droplets and bring the virus into their bodies. This is thought to be the main way the virus spreads, though a person touching an infected surface and then touching his or her eyes, mouth or nose might also get sick.

The virus can infect the upper respiratory tract the nose and throat, for instance or travel down into the lungs, including alveoli air sacs that bring oxygen into the bloodstream and expel carbon dioxide.

The virus then uses its spikes to attach to cells. Once attached, the virus inserts its genetic material, RNA. Thats used to create particles that are assembled to create more of the virus. Those are ejected from the cell and become attached to other cells, replicating the virus in the respiratory tract.

A virus cannot live by itself. It has to have a living cell in order to continue reproducing, said Dr. Laila E. Woc-Colburn, an associate professor and director of medical education for the National School of Tropical Medicine at Baylor College of Medicine. The cell serves as a little factory to produce more of them.

How does the body respond?

Each cell has its own internal defense system. Much like a home alarm would go off, the cell activates its own defenses and then calls for help from the immune system. Cytokine proteins bring in white blood cells to help fight the virus.

The release of cytokine proteins causes inflammation, which prompts symptoms such as fever, body aches and feeling tired. The dry cough associated with COVID-19 could be caused by inflammation or injury in the respiratory tract.

For many people, the bodys response will succeed in killing the virus over time. But for some, the release of cytokines can be too aggressive of a response, leading to acute respiratory distress syndrome and other respiratory issues that require a breathing tube.

It might even lead to shock, when organs dont receive adequate blood supply and oxygen, and organ failure.

Your immune response can overreact and cause more damage than the virus itself is causing, said Vineet D. Menachery, assistant professor in the Department of Microbiology & Immunology at the University of Texas Medical Branch, and this is particularly pronounced in older people and people with health issues.

How long am I contagious for?

Some people can be contagious before showing symptoms. And that contributes to the virus spreading because its hard to identify people who are sick.

By the time you figure out somebody is infectious, they probably have already transferred the disease to other people, said Dr. Howard J. Huang, medical director of lung transplantation at Houston Methodist Hospital.

People are thought to be most contagious when they are the sickest, and they can remain contagious for weeks after their symptoms disappear, with the exact timeframe unknown.

Am I immune to COVID-19 if I survive?

Yes, at least in the short term.

The body creates antibodies to help ward off future attacks. But since the new coronavirus has only been found in humans since December, its not yet known how long the immune system will remember this virus. Some viruses, like those that cause the flu, require a vaccine every year.

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Is this new coronavirus more prone to mutate?

No. Huang said it is mutating at a slower rate than influenza, with the latest data showing at least eight strains circulating worldwide.

They have proofreading enzymes that keep mutations lower than most RNA viruses, added Menachery. Therefore, they are more stable than other viruses like influenza.

Is there a vaccine?

Not yet, but a variety of research is underway to help treat or prevent COVID-19.

andrea.leinfelder@chron.com

twitter.com/a_leinfelder

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How the spiky coronavirus attacks your cells and makes them into little virus factories - Houston Chronicle

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