Since September 1995 the results of this communicable disease
surveillance have been available on a worldwide web site called
Sentiweb (http://www.b3e.jussieu.fr/sentiweb). Sentiweb also
provides an electronic version of our quarterly paper bulletin
Sentinelles , which is currently distributed to 60 000
doctors in France. Sentiweb can also be accessed from several important
health related web sites (such as those of the World Health
Organisation, Communicable Disease Surveillance Centre, Karolinska
Institute, and Centers for Disease Control and
Prevention).
Sentiweb provides a way to interactively consult the database.
Two kinds of outputs may be requested: time series of incidences of
cases and spatial spread of communicable diseases incidences in France.
The data can be visualised as maps or curves of incidences within a
selected range of time or space (fig 1). Maps may be produced
either by means of a classic fill in method based on administrative
contours or by a " kriging" fill in method based on iso-incidence
contours.( 3) The system allows a user to request as
many as 25 000 different maps and 10 000 graphs of time series. An
image is built in 3-15 seconds (excluding transmission time) depending
on the complexity of the request. Since its opening, Sentiweb has
provided about 9000 maps and time series.
Misuse of information
There is an unavoidable conflict between freedom of access to
information and the risk of spurious interpretation of this
information, leading in the worst case to a false alert. This is
particularly true when searches are made in units of space or time that
are too small, leading to analyses that are statistically meaningless.
The open philosophy of the Internet brings this problem into the public
arena. But do we have any alternative? How do we decide which of the
maps or curves are not suitable for public view? Information on small
numbers of cases is regularly published on many epidemiological
bulletins, and this may be also used spuriously.
We therefore consider that, instead of censoring material, we should
train users of the Internet to ask the appropriate questions of such a
database. We have posted warnings about inappropriate use of
information that appear when any requests for data are made, and users
can send email requests for epidemiological help. We also maintain a
weekly updated electronic report, written by epidemiologists in simple
words, to guide users in their interactive queries on the most recent
data. Moreover, the site provides links to other expert information
classified by topics (such influenza, diarrhoea) or by organisations
(such WHO, CDSC). Thus, users have the opportunity to extend their
expertise by comparing our data with those of other sources.
We thank the sentinel general practitioners who
collected these data. The Sentinel system was developed at lNSERM
(national institute of health and medical research) U.444 in
collaboration with the R|feseau National de Sant|fe Publique (public
health network) and the Direction G|fen|ferale de la Sant|fe (national
department of health).
Funding: The Sentinel system is supported by grants from
R|feseau National de Sant|fe Publique and Direction G|fen|ferale de la
Sant|fe.
Conflict of interest: None.
INSERM U.444,
Institut federatif Saint-Antoine de
Recherches sur la Sante
(ISARS), 27 rue Chaligny,
75571 Paris cedex12,
France
E Boussard,
computer scientist
A Flahault,
head of Sentinel system
J-F Vibert,
maitre de conferences des universites-practicien hopitalier
A-J Valleron,
director of epidemiology and
information sciences
INSERM unit
Correspondence
to:Dr Boussard (email boussard@b3e.jussieu.fr).
REFERENCES
1 Valleron A-J, Garnerin P. Computer networking as a
tool for public health surveillance: the French experiment. MMWR
Morb Mortal Wkly Rep 1993;41 :101-10.
2 Garnerin P, Saidi Y, Vallerron A-J. The French communicable
diseases computer network, a seven-year experiment. Ann NY Acad
Sci 1992;670 :29-42.
3 Carrat F, Valleron A-J. Epidemiologic mapping using the
" kriging" method. Application to an influenza-like illness epidemic
in France. Am J Epidemiol 1992;135 :1293-300.
(Accepted 7 November 1996)
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