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| SARS-CoV-2, a member
of the subfamily Coronavirinae. |
Covid-19
Coronavirus disease 2019 (COVID-19) is an infectious
disease caused by SARS coronavirus 2 (SARS-CoV-2), a
virus closely related to the SARS virus.
The disease is the cause of the COVID-19 pandemic. Those
who get the disease might get a fever, dry cough,
fatigue (tiredness) and shortness of breath. A sore
throat, runny nose or sneezing is less common. In very
bad cases, they can even get a much worse fever, fewer
white blood cells, and loss of appetite. They might
cough up blood, and have kidney failure.
People with this disease can get pneumonia and
multi-organ failure if they are weak, old, or are
already sick. There are people who are called
asymptomatic carriers, which means that they did not
have all or some of the symptoms of the virus. This is
very dangerous since they may not know that they have
the virus and can give it to other people without
knowing it.
The countries with the most sick people are the USA,
Brazil, and India. COVID-19 virus travels from person to
person through the air like the common cold does.
Scientists disagree about whether the virus is able to
hang in the air a long time and go far like the measles
virus does. |
|
Signs and symptoms
According to the United States Centers for Disease
Control and Prevention, COVID-19 makes people feel sick
in different ways, but it usually affects the lungs.
People usually cough and have difficulty breathing. They
often also have a fever, chills, headache, pain in their
muscles, or trouble tasting or smelling things.
According to an April 2020 study by the American
Gastroenterological Association, COVID-19 can make sick
people vomit or have diarrhea but this is rare. They
said about 7.7% of COVID-19 patients threw up, about
7.8% had diarrhea and about 3.6% had pain in their
stomachs.
Name
In February 2020, the World Health Organization
announced they had chosen a name for the disease caused
by SARS-CoV-2: COVID-19, replacing the temporary name
"2019-nCoV." "Co" is for "corona," "Vi" for "virus," and
"D" for "disease," and "19" for the year 2019. They said
they did not want the name to have any person, place, or
animal in it, like "Wuhan," because then people might
blame the disease on that place, person, or animal. They
also wanted the name to be easy to say out loud.
How the virus causes disease
The expanding part of the lungs, pulmonary alveoli, have
two main types of cells. One cell, type I, absorbs from
the air, i.e. gas exchange. The other, type II, produces
surfactants, which help keep the lungs fluid, clean,
infection free, etc. COVID-19 finds a way into a
surfactant producing type II cell, and smothers it by
reproducing COVID-19 virus within it. Each type II cell
which is killed by the virus causes an extreme reaction
in the lungs. Fluids, pus, and dead cell material flood
the lung, causing the coronavirus pulmonary disease.
Lung damage
Scientists looked at the lungs from people who died of
COVID-19. They compared them to lungs from people who
died of influenza A and to lungs from people who died
but not from any problem with their lungs. They saw the
cells that made up the skins of the blood vessels in the
lungs were more badly damaged in the lungs from COVID-19
patients, and there was more blood clotting. The most
important difference the scientists saw was that the
lungs had begun to grow new blood vessels.
Other organs
According to doctors and scientists from Columbia
University, the virus damages the inside of the blood
vessels, which causes blood clotting. The blood clots
travel through the body and can damage the heart,
kidneys and other systems. The virus can also damage
organs by itself. In New York City hospitals, 50% of
COVID-19 patients had kidney failure in some way. The
scientists said that the kidneys have many ACE2
receptors, the same receptor that SARS-CoV-2 uses to
sneak into cells.
Long-term effects
Some scientists, for example Robert Stevens of Johns
Hopkins University in Baltimore, are starting studies to
watch people who have recovered from COVID-19 to see
what long-term effects they have. Scientists think that
people who have COVID-19 and do not die might still have
lung or brain damage for the rest of their lives.
Other scientists saw that SARS-CoV-2 made the body make
less of the male hormone testosterone and considered
that SARS-CoV-2 could cause sterility the way the mumps
and other viruses do. A sterile man cannot father
children naturally.
COVID-19 and pollution
Scientists saw that more people died from COVID-19 in
places with large amounts of air pollution. One team of
scientists from Martin Luther University Halle-Wittenberg
looked at air pollution information from satellites and
statistics on COVID-19 deaths in Italy, France, Germany
and Spain and saw that places with large amounts of
nitrogen dioxide pollution had more people die from
COVID-19. Nitrogen dioxide can damage the lungs. |
|
Transmission and prevention
There are many ways to stop the spread of COVID-19.
Washing hands for 20 seconds or more will help kill the
viruses. Try not to touch your own face - eyes, nose, or
mouth - with unwashed hands.
People should stay away from crowded places if they can,
because being close to big groups of people can easily
spread the virus. In fact, many health organizations say
that people should stay at least two metres from another
person.
Many people wear face masks in public to stop getting
the virus, and it is recommended by countries such as
China, Hong Kong and Thailand. Most face masks work best
to stop you giving the virus to other people. When
people with the virus wear masks they give it to less
people. One study published in Cell showed that wearing
a mask pulled down to cover the mouth but not the nose
was not good. People usually breathe through their noses
and not their mouths. Scientists found that nose cells
were more likely to have virus in them than throat
cells. Because of this, the scientists said, breathing
out through the nose was more likely to spread the virus
than breathing out through the mouth, so people should
wear masks that cover their noses.
One study in China found the virus in semen from men
with COVID-19. The scientists wondered if men could give
COVID-19 to partners in sexual intercourse.
Tests and testing
Experts recommend testing people for COVID-19. Some
people may have SARS-CoV-2 in their bodies but not feel
sick right away. These people can spread the virus to
others.
There are two types of tests. Viral tests show whether a
person has the virus right then. Antibody tests show
whether the person had the virus and has since
recovered.
A group of scientists from Hokkaido University developed
an antibody test that could detect avian flu antibodies
in only 20 minutes. They said their test could be
changed to detect SARS-CoV-2. |
|
Medicines
The virus that causes COVID-19 is new to humans. This
means that there are no medicines that can stop people
from getting COVID-19 or that can treat them if they do
get it. Scientists are working hard to invent and test
new medicines. Some scientists are trying to invent a
new vaccine which would stop people from getting sick
with COVID-19. Other scientists are testing medicines
used for other diseases to see if those medicines make
people get less sick if they do get COVID-19.
Vaccines
In April 2020, the group Coalition for Epidemic
Preparedness Innovations (CEPI) said that scientists
were looking at 115 compounds that could be a vaccine.
Anthony Fauci, director of the U.S. National Institute
of Allergy and Infectious Diseases, says it takes 18
months to test a vaccine to make sure it works and is
safe.
In April 2020, scientists from the University of
Pittsburgh said they had made a vaccine, called
PittCoVacc, and tested it in mice.
Another team of scientists led by Dr. Josef Penninger of
the University of British Columbia invented a medicine
called APN01. They tested APN01 in engineered human
tissue. This is human cells put together to act like
part of the body, but it is not a whole animal or
person. They added a protein called "human recombinant
soluble angiotensin converting enzyme 2" (hrsACE2) and
saw that it stopped the virus from taking over cells.
They named their hrsACE2 APN01.
In late April 2020, a team from Oxford University said
that they had developed a COVID-19 vaccine. The United
States National Institutes of Health tested it in rhesus
monkeys, and it worked. Because they had already been
working on a vaccine against a different coronavirus,
they had a head start working on one for SARS-CoV-2.
They would try to test their vaccine on 6000 people by
the end of May 2020, and that their vaccine could be
ready for people to use in September 2020.
Other scientists are developing vaccines that use
messenger RNA to teach the body to recognize the virus.
They say mRNA vaccines will take less time to develop
and make than protein or whole-virus vaccines.
In mid-May 2020, a company called Moderna said they
tested their mRNA vaccine in forty-five people and eight
of them produced antibodiesbut they did not publish the
specific data or publish an article in a scientific
journal. Anna Durbin of Johns Hopkins University said it
was too soon to tell if people would keep the antibodies
long enough for the vaccine to work. The United States
Food and Drug Administration gave Moderna permission to
test the vaccine again in more people. Moderna's chief
medical officer said the vaccine could be ready in
January 2021.
Antibodies
Some scientists gave SARS and MERS to llamas so the
llamas' immune systems would make antibodies, or natural
medicines, against those viruses, and they found a few
antibodies that worked. In a May 2020 study, the
scientists said this could work with SARS-CoV-2 too. |
|
 Kiddle: Covid-19
Wikipedia: Covid-19 |
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