Few population-based studies have been carried out in France to investigate the level of anxiety generated by epidemic risk in the general population. The main objectives of this cross-sectional survey were to evaluate: i) extent of anxiety of epidemic risk; ii) knowledge level about infectious diseases; iii) reactions in the event of an epidemic or pandemic; and iv) confidence level in various sources of information.
Recruitment by the quota method enabled the selection of a representative sample, but the sample size was relatively small and limited to one region. Larger national studies are warranted to gain a broader understanding of the knowledge and anxiety pertaining to epidemic risk in the French population.
The study was carried out four months after the avian influenza epizootic occurred in France, providing the opportunity to evaluate the short- and medium-term impact of an epidemic on individual behaviours. About one quarter of the study population was concerned by epidemics, probably because of the public's overall confidence in the healthcare system and in its ability to handle such situations. Indeed, as soon as suspicion of avian influenza in a poultry breeding, surveillance measures including confiscation of the breeding, and controls of all movements (people, other animals, etc) in the suspected area were set up to limit the propagation of the infection. Relative powerlessness in the face of such a large event could also be a contributing factor. Similar arguments have been reported in a qualitative survey conducted in the U.K. and the Netherlands . Moreover, the majority of human epidemics reported by media have occurred in foreign countries (avian influenza and SARS in Asia, cholera, and hemorrhagic fever in Africa). Severe cases of infections such as the outbreak of legionnaire's disease reported by the media in France are rather sporadic. Pursuant to the present study, an outbreak of Clostridium difficile type 027 occurred in Northern France . However, to our knowledge, no data on worries and concerns of the general population have been published for this disease.
The higher reported concerns for cancers, unemployment and meningitis, reported also by other French studies  may be due to their higher prevalence and strong mediatisation in France.
In February 2006, the highly pathogenic avian influenza (HPAI) H5N1 virus was isolated in the Ain district, an important migration and wintering waterfowl area of the Rhône-Alpes region. The epizootic lasted two months and may explain why subjects living in this area were well informed about the disease. France was the first European Union country where non-wild birds had been implicated. After the epizootic, extensive media attention led to a decrease in visits to this area, particularly to a public bird park located in the district. These results emphasize the importance of implementing effective communication strategies for the general public. In the early phase of an outbreak, communication is usually targeted at a segment of the population considered at risk. In the rest of the population, this could create a feeling of complacency and lead to stigmatization and discrimination against the population labelled to be potentially at risk. Such attitudes have been reported during SARS epidemics [9, 11–14]. Another striking example is provided by AIDS. The earliest education and prevention campaigns were mainly directed at men who have sex with men and at young people. This approach may have contributed to an increase in the incidence of AIDS among heterosexuals and higher age categories [15–19].
Less than 20% of respondents with adequate knowledge of avian influenza reported avoiding travel to at-risk countries, but the percentage was higher among older subjects. Similar results have been obtained in a recent survey conducted among Finnish tourists in Asia during the avian influenza outbreak .
With the exception of SARS, the majority of respondents believed they had adequate information about other infectious diseases. The lower level of knowledge about SARS in the study population may be related to the absence of cases in France. The mean knowledge score of SARS was 1.2 in Europe and 1.7 in Asia (p < 0.0001) in an international survey involving over 3,000 respondents in five European and three Asian countries . The knowledge level about nosocomial infections and AIDS was substantially different between age categories. Younger people felt they were more at risk of acquiring a sexually-transmitted disease than they were of an infection during hospitalization and were, therefore, more likely to be informed about the former. They may associate hospital infections with old age and, for this reason, may be less concerned about nosocomial infections.
A civic-minded attitude emerged from answers under the scenario of the occurrence of a highly infectious disease. The population said it would follow advice given by public authorities and would agree to be quarantined, to wash their hands several times a day and wear a face mask. However, we should exercise caution in extrapolating the observed feeling of relative complacency towards epidemics in real situations. During serious outbreaks of disease, the population would probably move from a phase of calm and serenity to a phase of major panic without going through an intermediate stage. The SARS epidemic was an excellent example of this situation . Compliance with advice could also reflect anxiety and psychological distress . A positive dose-response gradient between self-protection and level of anxiety has been reported by a longitudinal telephone survey in Hong Kong . It is noteworthy that panic caused by local outbreaks may lead to worldwide reactions because the spread of pathogenic agents in modern societies is facilitated by extensive air travel.
Effective public health action is feasible by taking into consideration the public's knowledge of epidemics, their fears, psychological responses and compliance level with public health measures. International collaboration aimed at improving the understanding of these factors would alleviate public apprehension and enhance preparedness for and control of epidemic crises.
The results of the current survey showed that a large majority of respondents would not trust politicians and the media but would follow the advices of their physicians. Native population of two other European countries reported also most confidence in their physicians while foreign media and family/friends were the most trusted sources of information among Asian communities living in these countries . Identifying the communities' trusted sources of information would help authorities to effectively present preventive and educational messages. Governments should proactively reassure the population by becoming more involved in this public health issue. Suitable communications would reassure the population and improve control of the epidemic situation.
Some limitations of the study should be addressed. Because of the use of a phone survey, the questionnaire had a limited number of items. Content questions to validate the actual self-reported knowledge of infectious diseases were primarily focussed on avian influenza. However, with the exception of SARS, other cited infectious diseases were well-known prevalent and/or mediatised diseases. The results of this exploratory study could be the basis for more elaborated and comprehensive studies on risk perception in the French population.
The recent H1N1 flu pandemic alert  is a real time situation in which the public's risk perception could be explored. Population-based surveys become critical in the current context of the recent transmission of swine influenza viruses to humans. Unlike avian influenza, inter-human transmission of this pathogenic virus has been established . Furthermore, it has spread quickly across countries and borders, with several countries reporting laboratory- confirmed cases of the disease. Since the first case was identified in Mexico in early April 2009, various national and international health and governmental bodies have made plans to monitor and control this new outbreak. However, to better coordinate such plans, they must acquire information about the population's knowledge level of the disease, their feelings about it, the acceptability of a possible vaccine program, etc.