Excerpt (1 of 4 articles in this post]:
[4] Saudi Arabia outbreak investigation follow-up - newswire
Date: Wed 19 Jun 2013
Source: Metro News Canada, The Canadian Press report [edited]
http://metronews.ca/health/712340/saudi-mers-outbreak-showed-sars-like-features/
A
long-awaited report on a large and possibly still ongoing outbreak of
MERS coronavirus (MERS-CoV) in Saudi Arabia reveals the virus spreads
easily within hospitals, at one point passing in a person-to-person
chain that encompassed at least 5 generations of spread.
The
study, co-written by Toronto SARS expert Dr. Allison McGeer, also hints
there may have been a superspreader in this outbreak, with one person
infecting at least 7 others.
The study lays out what is known
about an outbreak of MERS that erupted this spring [2013] in 4 hospitals
in the Eastern [Ash Sharqiyah] Region of Saudi Arabia, in an area whose
name translated into English can be spelled Al-Ahsa or Al-Hasa (the
study uses the 2nd version). It was reported online on Wednesday [19 Jun
2013] by the New England Journal of Medicine [NEJM].
Superspreaders
played a key role amplifying SARS cases during the 2003 outbreak. That,
combined with the symptoms patients manifest when they become sick and
the long and varied incubation period, paint a picture that is
reminiscent of SARS for the authors, several of whom, like McGeer,
worked in Toronto to contain that coronavirus.
"This virus is
closer to SARS than anything else," McGeer, an infection control expert
at Toronto's Mount Sinai Hospital, said in an interview from Cairo,
where she was attending a World Health Organization meeting on MERS on
Wednesday [19 Jun 2013]. She travelled to Al-Hasa to help investigate
the outbreak in May [2013] and was on a WHO mission to Saudi Arabia
earlier this month [June 2013].
"If you want to think about how
you're going to prevent and manage hospital outbreaks, SARS is the place
that all of us would start."
The 2003 SARS outbreak infected
more than 8400 people in 31 countries, killing at least 916. In the main
it was an outbreak of hospitals, wreaking its devastation on staff,
patients and visitors of facilities in which it spread. MERS and SARS
are members of the same viral family.
McGeer said there are some
fortunate distinctions -- few health-care workers appear to be getting
infected with MERS -- as well as some worrisome ones. The high attack
rate among patients was "pretty unnerving," she said, as is the fact
that it appears people are infectious earlier in their illness than SARS
patients were.
SARS cases were contagious mainly late in their
illness, which gave health authorities a chance to diagnose and isolate
patients before they could make others sick. If MERS is contagious
earlier in the course of illness, "that's not good," McGeer said. "If
it's true, it's a real challenge because identifying cases early with
either SARS or MERS is really difficult."
Others too could see similarities to SARS based on the findings of the study.
"Clearly,
like with SARS, the health-care environment is a significant risk
factor for ongoing transmission," Michael Osterholm, an infectious
diseases expert who has been following MERS closely, said after reading
the paper. He was not involved in the work.
"It means that unless
the index of suspicion is very high and patients are immediately
handled with the highest level of infection control, you could surely
expect that you're going to see additional episodes outside of the
Middle East like are being seen in the Middle East."
Osterholm,
who is director of the Center for Infectious Diseases Research and
Policy at the University of Minnesota, said when cases have arrived
undiagnosed in European countries, hospitals there have been relatively
quick to figure out what they have on their hands and take measures to
protect against spread.
Still, imported cases triggered onward
spread in Britain, Italy, Tunisia and France, where transmission took
place in a hospital. In all those countries, transmission events ended
after a generation or 2 of spread because of measures taken to isolate
patients.
"The issue that we all worry about is what happens if
this gets into a country that doesn't have the same level of infection
control capability in a health-care setting, and what does that mean?"
noted Osterholm.
Saudi Arabia, which is one of 4 countries from
which MERS has spread and which has recorded the lion's share of cases,
draws millions of religious pilgrims each year from around the Muslim
world. The kingdom is also host to many guest workers, people from
poorer countries drawn to Saudi Arabia for work. Experts have worried
that both those patterns of movement could disseminate MERS to parts of
the world that might be ill-equipped to battle it.
The study
gives details of the 1st 23 cases in the Al-Hasa outbreak, infections
that date from [1 Apr 2013 to 23 May 2013]. It does not say whether the
outbreak in Al-Hasa has ended.
However, in the weeks since [23
May 2013], the kingdom's health ministry has announced 16 additional
cases of MERS. The ministry statements suggest at least 11 of the new
cases were from the Eastern [Ash Sharqiyah] Region.
The
statements do not say if these new infections are part of the outbreak
in the hospitals. Other possibilities are that they are people who
caught the virus from its still-unknown source in nature or,
potentially, from other infected people outside hospital settings.
McGeer
said she does not know if any of the cases reported since [23 May 2013]
are part of the Al-Hasa outbreak. She also does not know if the
outbreak is over, but warned with a disease that has an incubation
period as long as MERS -- out to nearly 15 days in some cases -- it can
take a long time to be confident that transmission has been stopped.
She
could not rule out the possibility that the chains of transmission in
this outbreak might now stretch beyond 5 generations, saying only that
it is possible they extend longer. That type of sustained spread
suggests the virus has no difficulty going from person to person, at
least in the right settings.
Dr. Trish Perl, another author who went with McGeer to Saudi Arabia, says this virus is capable of sustained spread.
"I
think that's one of the more important things that we show, is that
there really is ongoing human-to-human transmission. This is not a
single generation," said Perl, an infection control expert at Johns
Hopkins University in Baltimore, Maryland.
McGeer, Perl and their
fellow authors acknowledged this outbreak may actually have been
substantially larger than what it appears to be based on the confirmed
cases. Nearly a dozen [12] people were identified as probable cases,
based on their exposure histories and their symptoms. They tested
negative, but it has been seen elsewhere that some patients only test
positive after repeated testing.
"I'm not sure that we
effectively identified all of the probable cases outside of the
hospital," McGeer said. "I don't think it was twice the size. But it was
probably larger."
And some were not tested at all because the
hospitals were using the WHO's case definition, which requires
pneumonia. So people who were sick with respiratory symptoms and who had
had contact with MERS cases but who didn't have pneumonia were not
investigated as possible cases.
Perl said it may be time to amend the WHO definition, to encourage broader testing in situations like Al-Hasa.
The data in the study is the 1st large-scale revelation of what is happening in Saudi Arabia with MERS.
[Byline: Helen Branswell]
http://www.promedmail.org/direct.php?id=20130622.1787065
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