* Camels had virus in Qatari barn linked to people with MERS
* Study can't say if camels infected humans, or vice versa
* MERS has killed 71 people since emerging last year
By Kate Kelland
LONDON, Dec 17 Scientists have proved for the
first time that the Middle East respiratory syndrome (MERS)
virus that has killed 71 people can also infect camels,
strengthening suspicions the animals may be a source of the
Researchers from the Netherlands and Qatar used
gene-sequencing techniques to show that three dromedary, or
one-humped camels, on a farm in Qatar where two people had
contracted the MERS coronavirus (CoV) were also infected.
The study, published in the Lancet Infectious Diseases
journal on Tuesday, confirms preliminary findings released by
Qatari health officials last month. Camels are
used in the region for meat, milk, transport and racing.
But the researchers cautioned it is too early to say whether
the camels were definitely the source of the two human cases -
in a 61-year-old man and then in a 23-year-old male employee of
the farm - and more research is needed.
"This is definitive proof that camels can be infected with
MERS-CoV, but based on the current data we cannot conclude
whether the humans on the farm were infected by the camels or
vice versa," said Bart Haagmans of Rotterdam's Erasmus Medical
Centre, who led the study with other Dutch and Qatari
He said a further possibility is that humans and camels
could have been infected "from a third as yet unknown source".
"The big unknown is the exact timing of infections, both in
the persons and in the camels," he added. Both the men infected
in Qatar recovered.
Scientists around the world have been searching for the
animal source, or reservoir, of MERS virus infections ever since
the first human cases were confirmed in September 2012.
Globally to date, the World Health Organisation (WHO) says
there have been 163 laboratory-confirmed human cases of MERS,
including 71 deaths. The WHO is also aware of around a dozen
other probable but unconfirmed MERS cases in people.
CASES AROUND THE WORLD
In humans, MERS cause coughing, fever and pneumonia, which
can be fatal. Cases have so far been reported in Saudi Arabia,
Qatar, Kuwait, Jordan, United Arab Emirates, Oman, Tunisia,
France, Germany, Spain, Italy and Britain.
British researchers who conducted some of the first genetic
analyses on MERS last September said the virus, which is from
the same family as Severe Acute Respiratory Syndrome, or SARS,
is also related to a virus found in bats.
In the Qatar study, researchers collected clinical samples -
including nasal swabs, blood and rectal swabs, as well as stool
samples - from 14 dromedary camels living in a barn in Qatar
where in the previous week, the 61-year-old owner of the barn
had been diagnosed with MERS infection.
The samples were sent to laboratories in the Netherlands for
genetic analysis and antibody testing, which confirmed the
presence of MERS in three of the animals.
Researchers said the virus gene sequences were very similar
- although not identical - to those identified in the two people
from the same site.
They also noted that all 14 of the camels tested had
antibodies to MERS, suggesting the virus might have been
circulating among the animals for some time, allowing most of
them to build up immune protection against infection.
Since they were not able to say definitely whether the virus
had passed from the camels to humans, or the other way, the
researchers stressed they also could not rule out that other
common livestock species, like cattle, sheep and goats, or other
animals, may be involved in the spread of MERS.
To help find more answers, they said, researchers should aim
to plot detailed case histories of all human cases of MERS,
including any exposure to animals or animal products as well as
links with other infected people.
(Editing by Alister Doyle)