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Published Date: 2005-11-04 23:50:00
Subject: PRO/AH/EDR> Avian influenza, human - East Asia (159): China, H5 antibody
Archive Number: 20051104.3231

AVIAN INFLUENZA, HUMAN - EAST ASIA (159): CHINA, H5 ANTIBODY
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[The following information has been provided by
correspondents in response to the request posted
by Colleen McKay-Wharton
<McKayWharton@co.somerset.nj> on Thu 3 Nov 2005
as ProMED-mail post "Avian influenza, human -
East Asia (157): China, RFI 20051103.3214".]

[1]
Date: Fri 4 Nov 2005
From: Debora MacKenzie <d.mackenzie@chello.be-mail>

The source of the information concerning the
prevalence of H5 antibody in the Chinese
population is a paper by Peter Palese entitled
"Influenza: old and new threats" in Nature
Medicine Supplement, Vol 10, No 12, pp 582-587. Dec 2004
(<http://www.nature.com/naturemedicine>). The
following extract (pp 583-584) from this paper
provides the reference for the original data.

"Although H5N1 avian viruses were shown to cause
death in humans in 1997 and more recently in
2004, none of these strains was easily
transmitted from person to person. Also, none of
the H5N1 strains showed evidence of having
acquired genes from circulating human influenza
viruses. Whether this is a necessary requirement
for a pandemic strain to be successful is not
known. It would seem probable that such a
reassortment event between an avian and a human
influenza virus could have happened many times
over, either in humans or in animals. In fact,
seroepidemiological studies conducted among the
rural population in China suggest that millions
of people have been infected with influenza
viruses of the H4-to-H15 subtypes. Specifically,
seroprevalence levels of 2-7 percent for H5
viruses alone have been reported, and the
seropositivity of human sera for H7, H10 and H11
viruses was estimated to be as high as 38, 17 and
15 percent respectively (Shortridge,
1992). These findings predate the recent, highly publicized H5N1 cases".

Reference
---------
Shortridge, K.F. Pandemic influenza: a zoonosis?
Semin. Respir. Infect. 7, 11-25 (1992).

--
Debora MacKenzie
<d.mackenzie@chello.be-mail>

[ProMED-mail acknowledges with thanks the receipt
of similar information from A-Lan Banks
<A-Lan.Banks@thomson.com>, Massimo Battaglia
<Massimo.Battaglia@artov.inmm.cnr.it>, David
Price <dprice_1171@earthlink.net> and Robert B
Norgren <rnorgren@unmc.edu>. - Mod.CP]

******
[2]
Date: Fri 4 Nov 2005
From: A Confidential ProMED-mail source

A Comment from a Correspondent in China
---------------------------------------
Though the number of people involved is large, it
accounts for only about 2.9 percent or less of
the entire Chinese population. From the serum
surveillance reports posted in recent years, I
think it's a fair percentage for poultry workers,
but in the general population, the antibody level
to H5 strains only amounts to 0.48 percent in
Wuxi City and 0.75 percent in Shanghai. The
antibody level against H9 strain is higher. An
investigation in Shantou has found that 33.5
percent of the general population had antibody against H9 in 2004.

--
ProMED-mail
<promed@promedmail.org>

******
[3]
Date: Fri, 04 Nov 2005 09:03:23 +0100
From: Niklas Arnberg <niklas.arnberg@climi.umu.se>

I read your request for information this morning,
and I may have an answer to your question. I did
not attend the conference that you refer to, but
recently a colleague of mine, Dr. Urban Kumlin,
who is an expert in infectious diseases, showed
me a publication authored by Dr Kenneth Francis
Shortridge. Title: Pandemic Influenza: a
zoonosis? In: Seminars in Respiratory Infections. Vol 7. No.1 1992 page 11-25.

In this publication (table 7), there are data
demonstrating that up to 7 percent of the
population in certain areas in China are
seropositive to avian H5 (not H5N1 specifically).
The speaker may have assumed that most, or some,
of the avian H5 seropositives are actually avian H5N1 positive.

I do not know if this clarifies things for you or
for the readers of ProMED-mail. Nevertheless,
this publication does indeed demonstrate that
humans are frequently exposed to avian influenza
virus. The publication also contains data
demonstrating that up to 38 percent (!) of the
population in certain areas of China are seropositive for avian H7.

In a recent publication of ours, we suggested
that there are suitable receptors for avian
influenza virus in the human eye, and based on
analogies with other ocular viruses sharing the
same receptor specificity, we suggested that the
eye may be a portal of entry for avian influenza
virus. The implications of the findings by
Dr.Shortridge are further discussed in relation
to the eye as a possible portal of entry for
avian flu. See: Olofsson et al. The Lancet
Infectious Diseases. 2005. 5:184-188.

--
Niklas Arnberg
Assistant Professor
Department of Virology
Umea University
SE-90185 Umea
Sweden
<niklas.arnberg@climi.umu.se>

[The prevalence of antibodies to avian influenza
viruses, including H5, in the Chinese population
is striking. Significantly there have been no
confirmed human cases of avian H5N1 influenza in
China during the current outbreak in the area.

If this situation is mirrored throughout the
other H5-affected countries in East Asia, it
might explain the apparent absence of disease
among workers in the poultry-rearing and
processing industries in the region, and among
those involved in culling diseased poultry. (The
single confirmed case of H5 infection of a
poultry worker appears to be an asymptomatic case
in Indonesia, diagnosed retrospectively.) It may
be that workers in the poultry industry are
protected by their pre-exposure to avian
influenza viruses (and inadvertent immunization),
in contrast to those in domestic situations
handling diseased birds without prior exposure to
avian influenza viruses. Seroprevalence studies
throughout the whole region should be given highest priority. - Mod.CP]

[Elsevier reference:
Alvarado de la Barrera, Reyes-Terán CG.
Influenza: Forecast for a Pandemic. Archives of
Medical Research. November-December
2005, 36(6):628-636
<http://www.sciencedirect.com/science?_ob=GatewayURL&_origin=SDPROMED&_urlVersion=4&_returnURL=&_method=citationSearch&_version=1&_volkey=01884409%2336%23628%236&md5=d148860841f70fb668161f7fec998274>]

See Also