Saturday, October 18, 2014

The Ebola Virus


The Ebola virus is uniquely terrible for many reasons, but it doesn't actually kill you. Your own immune system does.
In its struggle to beat back the virus, your immune system's reaction ravages the rest of your body, leaving your blood vessels weak and leaky.
Soon, blood and plasma start pushing through, sometimes coming out of your pores and every orifice.
But long before the body begins to fail — around the time Ebola first enters the blood — the virus starts tripping up our defenses.
Here's how it kills, how it spreads, and how it can be treated. In every step of the way, this deadly virus is uniquely terrible.

How It Gets In 
Ebola is a filovirus, a type of virus made from a tiny string of proteins that coat a single strand of genetic material. Particles of the virus live in an infected person's blood, saliva, mucous, sweat, and vomit.
When someone is at the height of the illness (typically after five or more days), one-fifth of a teaspoon of that person's blood can carry 10 billion viral Ebola particles, The New York Times reports.
An untreated HIV patient, by comparison, has just 50,000 to 100,000 particles in the same amount of blood; someone with untreated hepatitis C has between 5 million and 20 million.
If those particles find an entry point, like a cut or scrape, or if a person touches his or her nose, mouth, or eyes with fluids that contain them, they get to work quickly.


How It Kills
Once inside the bloodstream, the virus targets a compound called interferon. Interferon, named for its role in "interfering" with the virus' survival process, alerts the rest of the immune system to the presence of a foreign invader. Normally, interferon would deliver its warning message straight to the cell's command center via a special "emergency access lane."
Ebola is too smart for that old trick.
The virus hijacks the delivery process — preventing the immune system from organizing a coordinated attack — by attaching a bulky protein to the messenger. In its misshapen form, the messenger can't enter the cell. The immune system remains unaware of the problem, and the virus gets free range to attack and destroy the rest of the body.
This is when Ebola goes on a replication rampage. Once the virus starts growing, few things can stop it.
The virus starts infecting organs, killing the cells inside and causing them to burst. All of their viral content pours into the blood. By this time, the immune system begins responding to the crisis in turbo mode, but it's far too late. Rather than destroying the virus, our defenses simply rip our own bodies to shreds — from the inside out.
The World Health Organization has said the virus seems to kill about 70% of people infected, though it's hard to know the true numbers while the outbreak is still in progress.

How It Spreads 
Although Ebola spreads less easily than a cold, because it isn't airborne, the Ebola virus is far more persistent.
Like cold germs, Ebola virus particles survive on dry surfaces, like doorknobs and countertops, for several hours. But unlike a cold virus, which primarily infects the respiratory tract, Ebola can also live in bodily fluids like blood and saliva for several days at room temperature.
Doctors have found Ebola in the semen of men who have survived the virus up to three months after they recover.
It's important to remember that someone with Ebola isn't contagious until he or she starts showing symptoms. This happens when enough of a person's cells have been overtaken by the virus, a process that scientists say appears to require a hefty load of viral particles in the body.
There's also the prospect of Ebola mutating into something more deadly. Peter Jahrling, one of the head scientists at the National Institute of Allergy and Infectious Diseases, thinks the virus could already be changing into something more dangerous, Vox reports.
In recent tests with Ebola patients in Liberia, Jahrling has noticed that the infected seem to have more of the virus in their blood, which could presumably make them more contagious.
And even worse, it preys on our human need to touch and care for the sick, which is why much of its spread is to caregivers and healthcare workers.
"The mechanism Ebola exploits is far more insidious," as Benjamin Hale wrote in Slate. "This virus preys on care and love, piggybacking on the deepest, most distinctively human virtues."
That's why the virus strikes children, their parents, families, and communities. All it takes is one small slipup, one uncalculated act of humanity, and the disease spreads even further.

How It Is Treated 
It's tough to believe that anyone could survive Ebola, given its quick and violent progression. But two Americans did, and thousands of people in Guinea, Liberia, and Sierra Leone have as well.
The virus' quick progression makes comprehensive treatment in a well-equipped facility key for raising one's chances of survival. If doctors can keep a person strong enough for long enough, that person's immune system can eventually clear the virus on its own.
In Atlanta, two Americans were nursed back to health with a combination of experimental drugs and traditional treatment. By keeping their patients' organs working with intravenous fluids (to replenish the body with the fluids it is quickly losing), ventilators (to keep the lungs pumping oxygen throughout the body), and drugs to keep blood pressure from dipping dangerously low, they gave them the best chance of survival.
That sort of treatment is pricey, though.
The bill for the average Ebola patient treated in the US is a lofty $1,000 per hour. In West Africa, where that sort of money isn't available, most patients simply go home to die.
To date, no federally approved vaccine or medicine for Ebola exists.


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