Learning how the coronavirus affects the body offers clues to fight COVID-19


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The devastating damage the new coronavirus inflicts on the human body can trigger inflammatory havoc. As we learn more, doctors are gaining clues to hopefully prevent deaths and improve treatment.

Last December, COVID-19 entered the world stage as a flu-like illness causing fever, a dry cough and a sore throat.

Since then, the list of how the disease can present itself has expanded, and has expanded further, to include gastrointestinal symptoms such as diarrhea, general pain, loss of taste and odor, and serious blood clotting problems, among others.

Of the more than five million infections worldwide to date, 2.4 million have restored.

Most infected people have so few symptoms that they are better off at home. The minority of serious infections in patients – mainly those over the age of 65, although no age group is free – can confuse the healthcare professionals who care for them.

The disease can worsen at a serious stage called acute respiratory distress syndrome, which includes severe inflammation and lung damage. These are often the patients who are admitted to intensive care units and who need ventilation.

Dr. Lynora Saxinger, a doctor specializing in infectious diseases at the University of Alberta, co-chairs a provincial scientific advisory committee examining how COVID-19 manifests and what it means to reduce transmission and extend treatment beyond current care measures.

“The landscape is changing very quickly,” said Saxinger. “We just want to make sure that we don’t miss [what] could spread, because that’s where we’re going to get in trouble. ”

Non-typical clots

As the initial anecdotes about inflammatory effects such as complications of blood clotting came up in a clearer signal of caution, clinicians have adapted their care as scientists sought to understand why this is happening.

Now, Saxinger said there was more evidence of coagulation damage in large and small blood vessels. “This virus does different things in the body. “

A better understanding of how COVID-19 manifests could inform efforts to reduce its transmission. (Lee Jin-man / Associated Press)

Experts say some of these inflammatory effects seem to be unique to this particular coronavirus, known as SARS CoV-2.

Dr. Zain Chagla, associate professor of infectious diseases at McMaster University in Hamilton, Ontario, said the extent of coagulation with this virus differs from other infections, including deadly SARS and MERS coronaviruses. With COVID-19, clots occur in the veins of the legs and lungs, as well as in the arteries that cause stroke and can lead surgeons to resort to amputation of a patient’s limbs.

Medical researchers have also discovered tiny clots that damage body tissue in hospital patients and autopsies.

Chagla said it means that “therapeutically” it might be best to give patients a low dose of heparin, an anticoagulant or an anticoagulant. It is often used before surgery and in various medical conditions to prevent and treat clots.

Researchers in clinical trials are also studying the use of high-dose anticoagulants in carefully selected patients, said Chagla.

This week, Minister of Health Patty Hajdu announced an accelerated route for clinical tests to help find answers to urgent questions about diagnosis, treatment, mitigation or prevention of COVID-19 while ensuring patient safety.

Montserrat Puig of the U.S. Food and Drug Administration and his team released on Friday what they called a road map for effective treatment of COVID-19, based on both reorient existing approved drugs as well as those under development.

The journal, published in Frontiers in Immunology, uncovers the factors leading to the “cytokine storm” that can be unleashed in people with severe COVID-19. Cytokines are small molecules released by the body’s immune system to coordinate the response to an infection or injury, ranging from mild fever to suspected deaths during the 1918 flu pandemic.

Heparin, an anticoagulant or an anticoagulant, is used for a variety of conditions, including, in low doses, COVID-19. (Jeffrey Sauger / Bloomberg / Getty)

Scientists are still working to understand the key events in the body’s cells, tissues and immune system that tip the balance between a normal, protective call, “hey, come help” for backups to an unnecessary call to four alarms that leads to a threatening excessive reaction life.

Puig wrote that potential drugs include those that could prevent the virus from entering our cells in the first place, antivirals to prevent the virus from reproducing, and therapies called monoclonal antibodies that suppress the response of the cytokine sirloin.

Onset of an inflammatory storm

People who develop symptoms of COVID-19 do so within 14 days, and this mainly occurs about five days after exposure.

The subsequent expected waves of the pandemic mean that COVID-19 will not be unique, said Dr. Lynora Saxinger. (Martin Weaver / CBC)

Saxinger said that when patients struggle with congested lungs and poor control of blood pressure, it is often a manifestation of lung inflammation in response to the infection.

She said there was also a storyline in how the disease travels through the body, from initial infection to damage until it heals or dies.

“The initial infection triggers this devastating body-wide response,” said Saxinger. “Then when the infection itself can be brought under control, it’s almost as if you unleash this storm of immune response and inflammation. “

Once the storm has started, doctors say treating the infection is unlikely to help much.

So what could help? As doctors report more symptoms, scientists working in parallel explore why and how the virus replicates so well in certain tissues and organs.

Matthew Miller, associate professor of infectious diseases and immunology at McMaster, tracks scientific progress.

The virus appears to use a receptor called ACE2 to enter human cells. Miller said that many groups of researchers are trying to understand which cells in our body have active proteins where the virus could replicate and cause disease.

“It is very important to know which cells a virus is capable of infecting, because it can help us anticipate what types of diseases or what types of symptoms they can cause,” said Miller.

It is believed that the infectious dose to which a person is exposed, as well as tiny genetic differences in the individual and whether they have underlying health conditions (such as heart disease or diabetes) all play a role in how COVID-19 manifests.

Understanding the virus to guide reopening

At the moment, medical researchers are studying how the acceleration of a beneficial aspect of the immune response that cells normally use to kill a virus could be supplemented by “immune modulators” to reduce excessive reactions. It’s a delicate balance and timing is key.

Miller said that when we learn more about the unique features of SARS-CoV-2, governments and public health officials have been forced to “learn on the fly” and adapt disease control plans. pandemic designed for another respiratory infection: the flu, commonly known as the flu.

“One of the areas that this pandemic has really brought to light is that there is not enough focus on prevention control measures,” he said.

Countries have imposed and eased closings without a clear understanding of what measures work best for this particular virus, leading to worldwide differences and changing recommendations about wearing masks or physical distance.

“I think we all learn that we don’t understand as well as we should,” said Miller.

WATCH | Why we should expect COVID-19 waves:

What mathematical simulations tell us about how the COVID-19 pandemic will unfold in the real world. 5:04

The basic principles of public health such as staying at home in case of illness, washing your hands and the cough label apply to all respiratory pathogens. These are the specifics that are still under construction.

For Saxinger, these knowledge gaps mean that understanding COVID-19 will be a long-term endeavor.

“It won’t just be one, we’re done,” said Saxinger. “We are all going to have to find the best way to manage people and try to give them the best possible results. “

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