HUNTING VIRUSES THAT PLAY HIDE AND SEEK
Every year, two
million children die of acute respiratory infections. Among the culprits are
several different viruses, one of which your child almost certainly has had
without you or the doctors ever knowing it.
The good news is that
researchers believe you are most likely immune after having had this virus just
once.
The human
metapneumovirus (hMPV) often appears disguised as a cold. Part of the reason it
has stayed hidden from doctors is that it was only discovered in 2001. A team
of Dutch virus researchers had the thrill of a lifetime when they realized that
they had discovered a new virus. Their joy certainly wasn't lessened by the
fact that the virus they discovered turned out to be one of the most common
viruses in children who are hospitalized due to respiratory complications.
According to the World
Health Organization, two million children die annually from acute respiratory
infections. Even though the hMPV virus has been able to hide from researchers
for a long time, it is not necessarily something you want to experience. Most
people will have symptoms similar to a cold, but for some, the virus causes the
respiratory system to swell and clog with mucus.
In developing
countries, a lot of these children die. In Western countries, infected children
are hospitalized and given treatment to help dislodge the mucus and ease
breathing. In the hunt for the virus or bacteria that is ravaging a sick child,
doctors often find other bacteria. It doesn't take much to prescribe a course
of antibiotics when this happens, just to be on the safe side. The global
increase in antibiotic-resistant bacteria is evidence that this process is
often unnecessary.
There is just no good
way to see if hMPV is the main culprit. At least not yet.
Ingvild Bjellemo
Johnsen, an Outstanding Academic Fellow at The Norwegian University of Science
and Technology (NTNU); is working to discover everything she can about hMPV and
the body's response to it. The goal is to understand this interaction well
enough to develop new vaccines, good diagnostic tools that allow doctors to
more easily find the virus in the body, and new forms of treatment.
This way, more
children in developing countries will survive hMPV infections, and the global
increase in antibiotic-resistant bacteria may be slowed. These are no small
tasks. Luckily, she has been thinking about viruses for the last ten years.
"I like viruses
because they're smart," Bjellemo Johnsen says. "They adjust to our
cells in a way that benefits them."
She is most
preoccupied with how the immune system is alerted when a virus comes to call.
Viruses have one clear goal: to reproduce. To do so successfully, they must be
incredibly good at one thing, namely hiding.
On the inside and on
the surface of our cells, there are "watchdog" organelles that sniff
out viruses and bacteria. They send out warning signals to alert the rest of
the immune system about the intruders, which is set into motion attacking the
offending virus or bacteria.
Many viruses are able
to disrupt or prevent these signals to the point where it results in serious
illness and in the worst case, death. This goes for viruses such as Ebola or
HIV. Our cells are not able to kill the intruders, so the virus is able to
reproduce freely. It is the interaction between viruses and our immune system
that Bjellemo Johnsen is trying to understand down to every last detail.
This is what her
typical work week looks like: On Monday, she prepares tests of different types
of cells from the human body.
On Tuesday, she turns
off a single gene that corresponds to a type of protein in the cells, to see
what role this particular protein plays in dealing with viruses.
On Wednesday, she adds
a virus and lets it infect the samples for 24 hours.
On Thursday and
Friday, she measures the effect of the virus on the samples.
Next week, she does
exactly the same thing again. To ensure the quality of each test, she does this
three times for each gene and each virus.
"This is how I'm
trying to understand the importance of different proteins when this particular
virus enters the body. In a few years, I hope to have a lot more answers,"
says Bjellemo Johnsen. There are an estimated 20,000 -- 25,000 genes in every
cell that can express over 20 million proteins.
"I'm not hunting
blindly. We work based on hypotheses about certain proteins being more
important than others," she says. "As a researcher, you have to
tolerate answers being negative. You just have to start a new week of work,
continue looking."
In addition to being
one of NTNU's Outstanding Academic Fellows, Bjellemo Johnsen is a part of a
interdisciplinary group of researchers from NTNU and St. Olavs Hospital called
CAIR, the Childhood Airway Infections Research Group. The group is comprised of
paediatricians, researchers and microbiologists working with airway infections
and children.
Asthma is a chronic
inflammation. It is the most common cause of hospitalization among children in
Norway, a big problem for those it affects, and resource-intensive for society.
According to the World
Heath Organisation, 235 million people have asthma globally.
"The reasons that
we develop asthma are not very well understood," Bjellemo Johnsen says.
"It looks like
there is some kind of relationship between having a serious respiratory
infection early in life and developing asthma later. I'd like to look more at
this."
She has access to a
solid database of tests from more than 4000 children hospitalized with
respiratory infections at St. Olavs Hospital in Trondheim, Norway. These tests
will be combined with laboratory experiments to uncover potential relationships
between respiratory viruses and the development of asthma.
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