If you've been paying attention to the news recently, you've probably
heard that several countries in western Africa are currently contending
with the world's deadliest Ebola outbreak.
In developments that hit a bit closer to home, over the past week,
three hospitals in New York City have isolated and tested patients
suspected of potential Ebola infection, the most recent case at Mount
Sinai Hospital in Manhattan making the news yesterday.
The patients all presented with potential Ebola-like symptoms (such as
fever, gastrointestinal distress, headache), and several of them had
traveled recently in western African countries. Fortunately, the New York Times reports
that, so far, no new Ebola cases have been confirmed in the United
States. According to a press release from Mount Sinai, the CDC is
conducting tests on a specimen from the patient, who is currently in
isolation, but "stable and in good spirits." Experts expect that he will
not test positive for the disease, and that the isolation treatment is
due to an abundance of caution.
Nevertheless, the unsettling news of suspected Ebola patients in
Manhattan comes during the same week that two American aid workers, both
infected with the virus after treating Ebola patients at a missionary
clinic in Liberia, are receiving treatment at Emory University in
Atlanta, Georgia. The first aid worker, Dr. Kent Brantly, 33, arrived in
Atlanta two days ago; the second, Nancy Writebol, 59, who works with
the international aid group SIM USA, arrived via jet in Atlanta today,
reports the
Charlotte Observer.
In light of the recent developments, we reached out to two experts:
Chris Basler, Ph.D., a virologist specializing in Ebola at the Icahn
School of Medicine at Mount Sinai in New York City; and Tim Lahey, M.D.,
an infectious disease specialist and associate professor of both
medicine and microbiology and immunology at Dartmouth’s Geisel School of
Medicine. Here’s what they had to say. (Note: In some instances, their
answers have been edited for length and clarity.)
WH: First things first. How is Ebola spread? Dr. Basler: All
the available information is that it spreads from person to person
through contact with bodily fluids from an infected individual. It
doesn’t seem to spread by being in close proximity, or by casual
contact. The recommendations are that you avoid contact with infected
individuals’ blood, feces, or other bodily fluids.
Dr. Lahey:Even sitting next to a person with
Ebola is thought not to be enough to transmit the disease, you need
contact with body fluids. If that person sneezes on you, or bleeds on
you, or a lot of sweat gets on you, then there is risk of transmission
because body fluids have transferred from one person to the other, but
Ebola is not airborn. So it requires those visibly obvious things to
happen for transmission to occur.
That’s also why Ebola doesn’t typically spread like wildfire through
communities, because how many people do you have that kind of contact
with?
WH: When you say “contact with body fluids,”
what exactly does that mean? If the fluids get on your skin? Or do they
have to go into a cut or a mucus membrane, like into your eyes or
something?Dr. Lahey:That’s the big
concern, is getting a splash to the eyes is the big thing you worry
about. I actually have not seen specific data on whether someone with
Ebola whose body fluids get on completely intact skin, compared to a
wound. I haven’t seen that type of direct comparison. The precautions
that the CDC gives out say that providers should use gowns regardless of
whether they have a wound or not. The safe option is to presume that
any contact with body fluids confers some risk of transmission. But I
think we’d all be most worried about contact that involves mucus
membranes like mouth or eyes.
WH: So it takes anywhere between two and 21 days from the
time of exposure until you start seeing symptoms. Are you contagious
during that time? Dr. Lahey:No, its generally believed that you’re not contagious until you start showing symptoms.
WH: I’m envisioning a scenario where someone sneezes on the
subway and suddenly everyone who rides the 7 train (like I do) becomes
infected.Dr. Basler: The idea that it can be spread on the subway by a sneeze is relatively unlikely.
Dr. Lahey: It’s a difficult question to answer,
because how do you put it? There is conceivable risk there, but the risk
in reality is just incredibly small. What’s the likelihood that someone
with Ebola is going to be sitting in a New York City subway? First, how
many cases of Ebola are there? Around 900 in the world today. And then
you say almost all of those cases, with the exception of the few cases
we’ve heard about in Nigeria and the United States, are in Sierra Leone,
Guinea, Liberia, where most of the people are not international
jetsetters. These aren’t people who just hop on a plane easily. The vast
majority of people infected with Ebola are very unlikely to leave their
region.
So let’s say there is someone… an aid worker who was not known to
have Ebola and traveled to the United States, when he was asymptomatic,
and then later became symptomatic after arriving. That’s the person you
should worry about. British Airways is no longer flying to a couple of
those countries to minimize that risk.
In any case, if someone like that was to become symptomatic and sick
with Ebola and for whatever crazy reason was also not telling people or
seeking help, and was also out on the subway, then… I guess it would be
possible to transmit on the subway, via throwing up or sneezing. Those
are conceivable risks. How likely? Hard to say. It’s conceivable. But
all these things have to line up perfectly for it to be possible. And
then on top of that, you'd have to have direct contact with his body
fluids. [
Editor's note: So if he sneezes on one end of the car, you'll be perfectly fine if you're not in his immediate proximity.]
Let me put it this way: There are way more common infections that
we’re much more likely to be exposed to that are much greater cause for
concern.
Or another way: We all worry about the serial killer coming and
killing us, but in actuality the real risks in our lives are the
trampolines in our backyards, swimming, sports, driving a car drunk…
those are the things that actually kill us.
WH: If you have Ebola, is it in your saliva?Dr. Lahey: I think so, yes. Sweat, vomit, semen, breast milk, saliva… basically all bodily fluids.
WH: So it can be sexually transmitted also?Dr. Basler: There’s
some evidence that there can be sexual transmission of the virus for a
substantial period of time after at least some individuals have
recovered from infection. So they clinically seem better, but they can
still detect the virus in semen, and there’s at least one example of
that.
Dr. Lahey:There was a lab worker who was working
with Ebola and got infected. So this was someone very amenable to being
studied, and after he recovered from Ebola, which typically runs its
course in a couple of weeks, he allowed researchers to perform studies
on him. 61 days after initial infection or initial symptoms, he still
had detectable Ebola in semen.
WH: So he was clinically “recovered,” but it was still detectable in his semen.Dr. Lahey:Yes. If you’re lucky enough to survive Ebola, celebrate with a condom.
WH: How long does it take for someone to clinically “recover” from the virus?Dr. Lahey:Couple
weeks. Usually the easy way to remember it is on average it takes 2
weeks from exposure to develop symptoms, and from the time you develop
symptoms, death will occur within a couple of weeks, or you’ll survive.
Something like 40 percent of people survive.
WH: What’s the actual fatality rate? I’ve heard between 60 and 90 percent. Is that accurate?Dr. Lahey:I
suspect the death rates we’re hearing quoted are probably not as
applicable in the United States or Europe. The thing that causes death
from Ebola is organ failure and sepsis, and that is very difficult to
treat in Sierra Leone, for instance. But in the United States we have
great ICU care, and are much better equipped to prevent that. If
someone’s blood pressure is low, I can give them medicines to make it go
higher. If their kidney is failing I can give them dialysis until their
kidneys heal.
The next question of course is, well, what is the number? And nobody knows.
WH: So the way Ebola actually kills you is through organ failure… not the bleeding?Dr. Basler:Right.
The bleeding doesn’t happen in all patients. Even in a significant
number of fatal patients, you don’t see obvious signs of hemorrhage. So
this Hollywood picture that you’re bleeding from every orifice is not
particularly accurate. And even when there are manifestations of
bleeding, it’s usually not copious. When people die of Ebola, blood loss
is not a significant contributing factor.
Dr. Lahey:That’s right, it’s not like the
bleeding is so excessive that the patients become anemic or anything
like that. It’s distressing and causes risk of transmission, but just
like any infection, with Ebola virus, the blood pressure can fall, and
that causes bad blood flow to the organs, like the kidney, causing
kidney failure. It’s the same sort of thing that happens with staph
infections.
WH: Does that mean it manifests the way a staph infection would?Dr. Lahey:In
the end, it’s called sepsis. You have a profound inflammatory response
to an infection, and you lose the ability to deliver the blood as a
result. Sepsis from staph looks the same as sepsis from Ebola. As with
any infection there are different grades of severity. You get a little
touch of it, get a little extra fluid, that’s fine. Other people can be
in the ICU for a long time. It kind of looks the same depending on the
type of infection it is. Ebola stands out because of the rapidity with
which it comes on, the frequency of death, the hemorrhagic symptoms.
But if you have a serious infection from any bug, the final common
pathway is sepsis. That kind of looks the same with subtle variations
from bug to bug to bug. But the whole low blood pressure and organ
failure if untreated piece is really similar.
WH: I was listening to the radio this weekend and heard a
bunch of people calling in to say that the American aid workers who
contracted Ebola shouldn’t be allowed back in the country. What are your
thoughts on that?Dr. Basler:The
message from the CDC, which makes a lot of sense, is that any hospital
in the United States is able to house and treat an Ebola virus patient
safely. So there would be no reason to say that we shouldn’t bring back
an American with the disease to treat them under optimal healthcare
conditions. Within a hospital setting, the likelihood that a virus
transmits to another individual is extremely low, so I think there’s
very little to fear bringing these patients to the US.
WH: Ebola is a serious and terrifying public health issue in
several countries in western Africa. If people start contracting the
disease here in America, can we expect to see the same sort of
situation?Dr. Basler:The big
difference is that we have much better healthcare infrastructure and
medical facilities. So if an individual is shown to be infected with
Ebola virus, we could likely identify the people they’ve been in contact
with relatively ease, and monitor them for signs of infection.
Basically, the idea is that the virus is transmitted through close
contact from the individual to other people, so if you can identify
people who are potentially infected, the contacts of people who are
known to have infection, then you can monitor them and isolate them so
that they’re less likely to pass it to other individuals. That’s much
easier to achieve in developed countries, as opposed to less developed
countries.
WH: Many of the people contacting Ebola in Africa are doctors and aid workers. Why is that?Dr. Basler:I’m
not there at the site of the outbreak, but I’d assume this reflects
that these are people with frequent close contact with people who have
frequent ongoing infections. I don’t know the circumstances in which all
these healthcare professionals are interacting with the
patients—whether they have the protective equipment available to them,
or if they are well trained in protecting themselves—that would increase
the likelihood of them getting infected.
The standard precautions that medical personnel take in the United
States are likely sufficient to prevent them from becoming infected.
WH: What exactly are those precautions?Dr. Lahey:So
if you had a patient who had suggestive symptoms and also came from the
right area of the world, had exposure to a contact, then you have to
wear special personal protective equipment that nearly all hospitals
have. Those include face shields, masks, gloves and gowns. And one easy
way to do this that you’ve seen in the news is you can use that
full-body suit that includes the face shield and gloves, that’s one way
to do it.
WH: Most American hospitals are equipped with this sort of protective gear?Dr. Lahey:Yeah.
The really challenging part here in the United States isn’t typically
about having the equipment that’s needed to protect caregivers, but
having the thought process to think of using it. Symptoms of Ebola are
sort of nonspecific in the beginning. You can get in the situation where
you don’t think of it, you don’t take the precautions until you’ve
already been exposed.
The Mount Sinai case was a good example where they heard some very
general symptoms: fever, gastrointenstical symptoms, and if they hadn’t
heard of the western African virology, they might not have thought
anything of it. But because they knew what was going on in Guinea and
Liberia and Sierra Leone, and they knew this patient had recently
traveled in the area, they took precautions and put the patient in
isolation, just in case.
WH: What happens to a patient who is put in isolation?Dr. Lahey:For
the patient it’s relatively simple. Since Ebola is transmitted through
body fluids, all the patient needs is to be in a private room with a
door closed. That’s enough. Some things, like Tuberculosis, measles,
chicken pox, you need to modify the airflow in the room and it’s more
complicated. For Ebola, it’s not so easy to transmit, so it’s just a
room with a door closed, and everyone who comes and sees them has to
take those precautions, but the patient doesn’t have to do much.
WH: Is there anything else you think our readers should know?Dr. Lahey:I
think the big thing to focus on is that people are naturally curious
about this, it’s exotic, it’s new, it’s concerning, it’s getting a lot
of media play. Knowing that there are in fact incredibly low odds of
this causing any problems in the United States or developed world, and
even if it does, the likely scope of this is going to be small. Which is
why it’s important for us to keep our eye on the real global health
ball: There are millions of people dying every year of things like
malaria, HIV, diarrheal illnesses. I hope the coverage puts it in that
context. Ebola is novel and unusual, but a very small impact compared to
malaria, HIV, and TB.
