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Dr. Phan Xuan Trung
MEDIC Medical Center
254, Hoa Hao Street, District 10
Ho Chi Minh City
Webmaster, ykhoanet.com
Email:
phanxuantrung@gmail.com
Dr. Jean-Marc Olive
Chief Representative of WHO in Vietnam
63 Tran Hung Dao
Ha Noi
Email:
who@vtn.wpro.who.int
Re: Enquiry of cholera outbreak data
Dear Dr. Olive,
We are a group
of non-government doctors and epidemiologists based in Ho Chi
Minh city who are interested in public health issues in
Vietnam. We understand that you have been involved in the
monitoring of the recent outbreak, and we are writing to kindly
ask whether you could please share with us some scientific
information concerning the outbreak.
We have just
read your comment reported in Bloomberg.com (23/4/2008) in which
you state that dog meat was linked to the cholera outbreak.
According to the news service, you also state that
eating dog meat or other
food from dog-meat based outlets “is linked to a 20-fold
increase” in the risk of the disease. This is an important and
interesting fact, which we would like to enquire for more
information. In fact, we are surprised by the word “link” which
is considered too strong in the epidemiologic parlance.
We have
searched in PubMed for the evidence of the association between
dog meat and cholera, but we could not locate any such
evidence. Presumably, you and your colleagues have conducted a
study on the association between dog meat and cholera, but you
have not published the results. In that case we are concerned
that the Ingelfinger Rule has been violated.
If you have
conducted such a study, could you please share with us the
results, methodology, and interpretation. We specifically would
like to know what was the study design, how many individuals had
participated in the study, how long were they followed up, what
bacterium were tested in dog meat, what were the relative risk,
and how could you establish the cause-effect relationship that
you state in the media. We highly appreciate your help in
sharing with us those information.
We would like
to share with you some of our opinions as follows. Although
everything is possible, we -- non dog-meat eaters -- consider
that dog meat is unlikely linked to cholera. This is so,
because the meat must be well cooked before serving, and in such
a high temperature it is impossible for V. cholerae or
indeed any known diarrhea-causing bacteria to survive.
Dog meat is
often served with vegetables and shrimp sauce. We now know that
there is no V. cholerae bacteria in shrimp sauce. Indeed, 194
samples of the sauce have been tested and none was positive for
the V. cholerae bacteria. This is entirely expected because
shrimp sauce is a salt-preserved food, and it is well-known that
V. cholera can neither survive nor grow in such a NaCl
concentration condition (the salt concentration in Vietnamese
shrimp sauce is around 13-25%). Nevertheless, vegetable can be
infected with diarrhea-causing bacterium, because the way the
vegetable is grown and used in some parts of north Vietnam
(e.g., the use of human excrement as fertilizer, unwashed
vegetables, or washing vegetables with bacterium-infected
water) can be a source of transmission of diarrhea related
bacteirum.
We should also
point out that last October when the cholera outbreak occurred,
some Vietnamese health officials announced that shrimp sauce was
the cause of the outbreak, but in subsequent
investigations this was not the case.
As you know,
although dog meat is not popular in Vietnam, a section of the
community still considers it a delicacy (just as in Korea,
China, the Philippines, Laos, Cambodia, and Thailand).
Restaurants that serve dog meat and their related services
represent an industry, in which several people livelihood and
income are dependent on. Therefore, we are concerned that your
statement that dog meat is linked to cholera is not based on
scientific fact and can potentially cause serious difficulty to
the industry and its workers.
In any case, we
would be grateful if you could provide us with scientific
information on the association between dog meat and cholera
risk. We thank you in advance for your help.
We look forward
to hearing from you soon.
Yours
sincerely,
Dr. Phan Xuan Trung
Dr. Nguyen Dinh Nguyen
Dr. Nguyen Van Tuan
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