Google Plus:
Evidence is mounting against camels as leading suspects in a deadly mystery that's claimed more than
100 lives in the Middle East.
The biological
supervillain is the virus causing MERS-coV, short for Middle East Respiratory
Syndrome, a type of coronavirus.
Since the first documented
cases in spring 2012, MERS has sickened at least 339 people in Saudi Arabia
alone and killed nearly a third of them, according to the country's Ministry of
Health.
A recent surge in reported
cases -- including 26 new ones this past weekend -- has fanned concern the
outbreak might be shifting into a more dangerous phase.
Saudi officials see spike in MERS virus
With any newly recognized
virus, disease detectives start with a few key questions. What kind of illness
does it cause? How is it spread? And where does it come from?
Killer coronavirus in the Middle East WHO
tracks new coronavirus to Middle East Health workers infected with coronavirus
With regard to that last
question, a new paper leaves little doubt that at least one answer is camels.
Researchers from Columbia
University, King Saud University and the New York-based EcoHealth Alliance
managed to isolate live MERS virus from two single-humped camels, known as
dromedaries.
Should I be concerned
about new virus?
A genetic analysis found
numerous substrains in the camel viruses, including one that perfectly matches
a substrain isolated from a human patient. The findings are published in mBio,
the open-access journal of the American Society for Microbiology.
The attention on camels
isn't new; in February, the same group published a finding that nearly
three-quarters of camels in Saudi Arabia tested positive for past exposure to
the MERS coronavirus.
The new paper still leaves
many questions unanswered: For example, what other animals might harbor the
virus? Could it be bats, as some have suggested?
"There might be
another animal, but we don't know," says Dr. Ian Lipkin, who organized the
research as director of the Center for Infection and Immunity at Columbia's
Mailman School of Public Health. "We need more in terms of
surveillance."
Does the virus make camels
sick? Researchers don't know, says Peter Daszak, another study author and
president of the EcoHealth Alliance, which researches links between animal
health and human disease.
Perhaps most urgent: Has
something recently changed to make MERS-coV more dangerous?
Here, some of the evidence
is reassuring. Any avid mystery reader knows that a watchdog who doesn't bark
can be an important clue. With MERS, there is a lack of alarm bells from the
laboratory; so far there is no evidence that the virus is changing to attack
people more aggressively or to spread more easily.
There isn't enough
evidence to draw a firm conclusion, says Dr. Mark Denison, a leading expert on
coronaviruses and a professor of pediatrics at Vanderbilt University. It also
remains to be seen whether humans are being infected by more than one of the substrains
found in camels. "There's a lot more work that would need to be done"
to prove it, he says.
Those who study MERS-coV say
it's crucial to pin down just how the virus is transmitted.
"We need to know what
people are most at risk," Daszak says. "We don't know if they're
involved in camel racing, camel breeding, camel slaughter -- that's really
critical right now."
Lipkin says the virus
likely spreads in a variety of ways, but he'd like to see more aggressive steps
taken to prevent the possibility of people being infected by eating camel meat
or drinking raw, unpasteurized camel milk -- both of which are common in Saudi
Arabia.
He says the Saudis will
face special concerns again this fall when millions descend on the holy cities
of Mecca and Medina for the Hajj pilgrimage. As part of the ritual, animals are
sacrificed, and their meat shipped all over the world to help feed the hungry.
Saudis: More deaths from
respiratory syndrome
"The butchery will
begin in three or four months' time, and we have to have measures in place to
ensure that the animals aren't infected," Lipkin says. For example, he
says, officials could decide to forbid the slaughter of young camels for food
since younger animals are more likely to carry the MERS virus.
Dr. David Swerdlow, who
heads the team responsible for tracking MERS at the U.S. Centers for Disease
Control and Prevention, says the Saudi government took steps to discourage the
spread of the virus during last year's Hajj, including posting warnings to
discourage people older than 65, pregnant women or those who were
immune-compromised from making the pilgrimage.
Health authorities have
not yet decided what steps to take this year, Swerdlow says, but the United
States is watching the situation closely.
"Any time you have an
emerging infection that has a high case fatality rate, that's been around for
over a year, that has caused illness in multiple countries, that's caused
illness in travelers and health care workers, and for which there is no
treatment or vaccine, we're concerned. We've been concerned for a year and a
half, and we remain concerned."
No comments:
Post a Comment