Animals repeatedly infected people with MERS, study suggests
Animals appear to have infected people
with the deadly new MERS virus several
times, researchers report on Thursday,
but people are also infecting one another.
A deep genetic analysis of virus samples
taken from 21 different patients shows
Riyadh, Saudi Arabia as a kind of ground
zero for the ongoing outbreak. So far,
135 people have been diagnosed with
MERS and 61 have died from it.
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Middle East Respiratory Syndrome (MERS)
worries health experts because it’s related
to severe acute respiratory syndrome, or
SARS, which swept around the world in
2003, infecting around 8,000 people and
killing close to 800 before it was stopped.
Both conditions are caused by
coronaviruses, members of a family of
viruses that usually cause common cold
symptoms and which infect a wide range
of mammals.
Both also have been carried around the
world by travelers, who have gone on to
infect others. The United Nations says it
could cause a pandemic.
MERS first showed up last year, and while
it seems to be worst in people who have
underlying conditions such as diabetes or
kidney disease, it has killed people who
were otherwise perfectly healthy.
"All cases have been directly or indirectly
linked to one of four countries in the
Middle East (Saudi Arabia, Jordan, Qatar,
and the United Arab Emirates), with most
cases (90 cases and 44 deaths) reported
from Saudi Arabia,” the team, led by
Matthew Cotten of Britain’s Wellcome
Trust Sanger Institute and Ziad Memish of
the Saudi health ministry wrote in the
Lancet medical journal.
“Human-to-human transmission of MERS
has been documented in England, France,
Tunisia, Italy, and Saudi Arabia.”
Saudi Arabia has several programs for
tracing this virus and others. After an
outbreak in a dialysis clinic, clinics started
keeping track of which chairs patients sat
in and when, so that if someone became
sick they could trace back who else may
have been exposed.
But that won’t always show precisely
when a person became infected, or how.
The genetic analysis shows enough
variation in the viruses taken from the 21
patients to suggest it wasn’t the same
virus circulating around. People appear to
have been infected several times from
different animal sources. Other patients
appear to have been infected directly by
other people.
Bats are one suspected source of MERS,
but scientists say it’s unlikely they are
directly infecting people. Researchers
found a big chunk of the MERS gene in an
Egyptian tomb bat. Camels can also be
infected with coronaviruses and several of
the patients had direct or indirect contact
with camels.
Goats are another potential suspect. U.S.
researchers at Columbia University are
going through a batch of samples from
animals and hope they can find the
reservoir – an animal that is infected with
the virus, without being made sick. With
SARS, the virus was traced to civets –
animals sold in Chinese markets for food.
The results also show several links to
Riyadh. That might mean something in
Riyadh is the source – an animal market
perhaps. Or it just may be because Riyadh
is such a big city and many travelers in
Saudi Arabia pass through it.
Saudi officials are worried that they
haven’t found the definite source for the
virus yet, and the Hajj is coming up. That’s
the mass pilgrimage made by devout
Muslims every year to the Saudi city of
Mecca. This year it’s from October 13 to
18 and it’s expected to attract 3 million
travelers.
Memish has said that Saudi officials are
already cautioning the elderly, people who
have chronic illnesses, pregnant women
and children under 12 should stay away
this year, just to be safe. The U.S. Centers
for Disease Control and Prevention is also
cautioning U.S. muslims.
