A comment on monitoring of aid workers for avian influenza
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The terrible disaster affecting southeast Asia will certainly create
a number of public health challenges in the immediately affected
areas. However, there is the possibility that these events may lead
to a much larger pandemic influenza problem. The relief effort has
brought a number of people from around the globe to a region not only
affected by the tsunami but also affected by avian influenza. It is
possible that the [local] population in the area might have some
innate immunity due to repeated exposure to avian influenza. However,
with the influx of immune-naive foreign aid workers, there seems to
be a potential for spread into people who may be much more
susceptible. It is a safe assumption that hygienic conditions in the
area are going to be lacking for some time. In addition, many of
these workers might almost suspect that they will come down with an
illness because of the circumstances, and may simply shrug off the
1st signs and symptoms. As they return to their countries of origin,
they may unwittingly depart during the prodromal phase of illness
only to act as the index cases of pandemic flu in their countries.

It would be prudent for federal, state, and provincial public health
departments to set up surveillance systems to monitor the health of
individuals who traveled to help with the tsunami recovery efforts.

--
Michael Olesen
Infection Control Practitioner
Abbott-Northwestern Hospital
800 East 28th Street
Minneapolis, MN 55407-3799

It would be prudent for public health departments to set up surveillance systems in Thailand, Indonesia, and Sri Lanka.

Prior to the Tsunami, there were school closings in Thailand because of H5N1 infected pigeons falling from the sky (http://www.flu.org.cn/news/200411204655.htm).  The Tsunami displaced both humans and wildlife.  The case fatality rate for H5N1 in Thailand has been in excess of 70%.  Thus, the virus can clearly cause significant problems in the local population.  Likewise the virus generated infections leading to the deaths of 147 Tigers in a Thai zoo.  The case fatality rate for the tigers exposed to the virus may have been near 100%.  There is no published data suggesting the H5N1 virus has spared a human sub-population in Thailand, and no data indicating tourists or aid workers are more susceptible.

The situation in Indonessia is also cause for concern.  Although there have been no reported human cases, H5N1 has already reappeared this season in Indonesia and has infected poultry in densely populated provinces.  Although H%N1 infections were no reported until the beginning of this year in Indonesia, about half of the H5N1 isolates at GenBank are from 2003 indicating initial infections were well over a year ago in Indonesia.

The situation In Sri Lanka is also unclear.  Initial reports indicated that there was one influenza A and two influenza B cases.  Later reports indicated that the 9 deaths and 75 hospitalizations were related to influenza B outbreaks.  However, a case fatality rate in excess of 10% for human influenza infections is unusual and influenza B cases are usually milder than influenza A.  Concerns were also heightened by the culling and dying of chickens in the area.  Although the general population was told that the spread of infections was reduced, they were also advised to stay away from crowds. 

The death and destruction caused by the Tsunami has created an environment more conducive to spread of infectious diseases, and increased surveillance of all susceptible H5N1 hosts would be warranted.

Henry L. Niman, Ph.D.
President, Founder
Recombinomics, Inc.

Tsunami-related Disease Potential in Relation to Risk of Emergence of
Pandemic Influenza
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I think further discussion is warranted regarding the risk related to
avian influenza in the tsunami-affected areas, and the potential for
the emergence of a pandemic influenza strain.  Not yet remarked on is
that the geographic region affected by the tsunami is not the same as
the region affected by highly pathogenic avian influenza (HPAI)
outbreaks.

In particular:

In Thailand, 5 provinces have been affected by the tsunami: Phuket,
Krabi, Koh Phi Phi, Phang Nga and Koh Lanta.  Of these, only Phang
Nga has reported any HPAI outbreaks, and that was during February
2004.  All other Thai provinces that have reported avian influenza
outbreaks in the past 12 months are outside the area hit by the
tsunami.

In Indonesia, Sumatra was hit by the tsunami, mainly in the north.
Only South Sumatra province has reported HPAI outbreaks, one with
onset around 11 Dec 2003 and one with onset at the end of May 2004.

In Malaysia, the only state to report HPAI outbreaks is Kelatan
State, which is the northeast corner of peninsular Malaysia, i.e.,
the opposite side to that hit by the tsunami.

Other tsunami-affected areas, including Bangladesh, Myanmar, India
and Sri Lanka confirmed to the OIE between February and July 2004
that they are (or were at the time) free of HPAI. (For reference, the
OIE HPAI website is
<http://www.oie.int/downld/AVIAN%20INFLUENZA/A_AI-Asia.htm>.

This geographic observation is important not only in terms of
evaluating the risk of avian influenza infection during the relief
efforts, but also in terms of assessing the likelihood that locals
have some innate immunity against avian influenza due to previous
exposure (as suggested by Michael Olesen in an earlier posting. [see:
Tsunami-related disease potential - Asia (03) 20041229.3436].

Although it is encouraging to see that the affected regions differ,
we cannot dismiss the pandemic influenza concern.  It is possible
that unidentified avian influenza (AI) outbreaks have occurred in the
tsunami-affected regions.  It is also likely that national resources
will be diverted to disaster relief, potentially compromising the
ongoing avian influenza surveillance and control.

I echo the sentiment about the importance of human health
surveillance for relief workers and for local populations.  As well,
we should stress the importance of immunization and protection not
just against the usual suspects (cholera, malaria, etc.) but also
against human influenza.

Such immunization will reduce the risk of co-infections with avian
and human influenza viruses.  Relief workers should, therefore, be
immunized against human influenza as well as against other
travel-related diseases.

--
Aleina Tweed
Epidemiologist
BC Centre for Disease Control
655 West 12th Avenue
Vancouver, British Columbia, Canada

A Comment on Monitoring of Aid Workers for Avian Influenza
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The unsanitary conditions might make human close contact with
infected birds a larger problem, or unnoticed avian outbreaks may
occur as public health resources are overwhelmed in the area. And,
certainly medical aid workers have a higher chance of contact with
persons with respiratory illnesses.

But I would think there has been a larger influx of tourists from
around the world than there will be an influx of aid workers now. If
we were going to see a lack of natural immunity in foreigners,
increasing the risk of potential human avian influenza cases,
wouldn´t we have already seen it?

--
Ginger Switzer, ARNP, COHN-S
EHPEC Employee Health Practitioners, Educators, and Consultants

I write in response to recent ProMED-mail reports on avian influenza
A (H5N1), especially those discussing highly pathogenic avian
influenza in Thailand, which state there is a mechanism by which this
virus could "...acquire the ability to spread easily to and among
people" (see ProMED-mail post: Avian influenza, human - east Asia
(54): risk assessment 20041228.3425).

With the current crisis in devastated areas of Sri Lanka, India,
Thailand, Indonesia and elsewhere, there are at least 500 000 people
with insufficient clean water, food or shelter at immediate risk of
illness and death.  The actually number may grow much larger as teams
continue the grim task of counting the dead and assessing the needs
of survivors.  As dehydration, weight loss from inadequate caloric
intake, and waterborne illnesses take their toll, a population of
unhealthy humans living in difficult and crowded conditions will
develop.

If avian influenza A (H5N1) jumps into this population, there is the
potential for rapid evolution and amplification and then
dissemination of a virus capable of causing a human pandemic.  The
pandemic may not initially be detected due to the inability to
clinically identify influenza among a population with limited medical
access -- who will likely battle many different febrile illnesses.
In addition, detection of avian influenza A (H5N1) in domesticated
and wild birds will not be a priority.

We need immediate surveillance for avian influenza A (H5N1) in sick
people in this region as well as in domesticated and wild birds.
Teams must be mobilized quickly by appropriate public health
organizations and sent to sites in and around the disaster areas.

--
Wm. Chris Woodward, D.O.
Regional Medical Director, Midwest
Antiviral Global Project Team
Abbott Laboratories
5800 Sugar Creek Pike
Nicholasville, KY 40356