Re: Concerns arise over symptomless Egypt bird flu cases
AVIAN INFLUENZA, HUMAN (72): EGYPT, VIRULENCE
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A ProMED-mail post
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International Society for Infectious Diseases
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Date: Sun 12 Apr 2009
Source: The Independent online [edited]
<
http://www.independent.co.uk/news/science/new-bird-flu-cases-suggest-the-danger-of-pandemic-is-rising-1667526.html>
Infections in Egypt raise scientists' fears that the virus will be
spread by humans. This paradox -- emerging from Egypt, the most
recent epicentre of the disease -- threatens to increase the
disease's ability to spread from person to person by helping it
achieve the crucial mutation in the virus which could turn it into
the greatest plague to hit Britain since the Black Death. Last year
[2009], the government identified the bird-flu virus H5N1 as the
biggest threat facing the country, with the potential to kill up to
750 000 Britons.
The World Health Organization (WHO) is to back an investigation into
a change in the pattern of the disease in Egypt, the most seriously
affected country outside Asia. Although infections have been on the
rise this year [2009], with 3 more reported last week, they have
almost all been in children under the age of 3, while 12 months ago,
it was mainly adults and older children who were affected. And the
infections have been much milder than usual; the disease normally
kills more than half of those affected; all of the 11 Egyptians so
far infected this year are still alive.
Experts say that these developments make it more likely that the
virus will spread. Ironically, its very virulence has provided an
important safeguard. It did not get much chance to infect other
people when it killed its victims swiftly, but now it has much more
of a chance to mutate and be passed on. The WHO fears that this
year's [2009] rise in infections among small children, without
similar cases being seen in older people, raises questions about
whether adults are being infected but not falling ill, so acting as
symptomless carriers of the disease. Its investigation, due to start
this summer, will see whether this is happening by testing the blood
of people who may have been in contact with infected birds but who
have not themselves become sick.
John Jabbour, who works with WHO in Cairo, told Reuters last week:
"There is something strange happening in Egypt. Why in children now
and not in adults? We need to see if there are sub-clinical cases in
the community." He added that if the research did find such cases,
they would be the 1st to be discovered anywhere in the world. Though
he stressed that there was still no evidence of the disease passing
from person to person, other experts are also becoming alarmed.
Professor Robert Webster, of St Jude Children's Research Hospital in
Memphis, Tennessee -- who is the world's leading authority on the
disease -- told The Independent on Sunday [12 Apr 2009] that, while
he himself had not seen firm data, the WHO in Egypt was raising "a
very, very important issue" which should receive "maximum attention."
He added: "I hope to hell they are wrong. If this **** thing becomes
less pathogenic, it will become more transmissible." And Professor
John Oxford, of Queen Mary, University of London, said that any
evidence that H5N1 was becoming less deadly would be serious, as the
greatest cause for concern was the disease's ability to spread. Even
a much less virulent strain of the virus could result in a
devastating pandemic. Studies show that an outbreak that killed as
few as 5 percent of those it infected could still cause hundreds of
millions of deaths around the world.
[Byline: Geoffrey Lean]
--
Communicated by:
Dr.med Martin Dirksen-Fischer
Hamburg, Germany
<
MartinDirksenFischer@gmx.de>
[As of 5 Apr 2009, it remained true that there had been no deaths
among patients in Egypt with confirmed avian H5N1 influenza virus
infections since the resurgence of the illness in Egypt in late 2008.
11 of these 13 patients have been children 6 years of age or younger.
These data do indeed suggest that there may have been a reduction in
the virulence of the outbreak strain, and there is a perceived risk
of progression of the virus to less a virulent but more transmissible
form.
On the other hand, all the patients had exposure to diseased or dead
poultry, and they likely contracted infection from that source and
not from human carriers. Furthermore, there has been no evidence of
onward transmission of infection to family members.
Several of the children are still in critical condition, and all may
not survive. Another relevant factor in evaluation of the Egyptian
situation is the immediate resort to treatment with the influenza
virus neuraminidase inhibitor Tamiflu.
The proposed WHO study is an important initiative in attempts to
define properties of avian influenza virus that may convert it into a
human pathogen. - Mod.CP]
[see also;
Avian influenza, human (71): Egypt, Viet Nam, WHO
20090408.1359
Avian influenza, human (70): Egypt (QL), 63rd case
20090406.1336
Avian influenza, human (69): Egypt (BH) 62nd case
20090404.1299
Avian influenza, human (66): Egypt (BH)
20090402.1271
Avian influenza, human (59): Viet Nam (ST) NOT
20090325.1162
Avian influenza, human (56): Viet Nam (DT) NOT, (ST) susp.
20090321.1128
Avian influenza, human (55): Egypt (AT), Viet Nam (DT)
20090320.1118
2006
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Avian influenza (208): NS1 virulence determinant
20061106.3183]
......................................................cp/msp/jw
