Surveillance system integration: reporting the results of a global multicountry survey

OBJECTIVES

Currently, there is no comprehensive picture of the global surveillance landscape. This survey examines the current state of surveillance systems, levels of integration, barriers and opportunities for the integration of surveillance systems at the country level, and the role of national public health institutes (NPHIs).

STUDY DESIGN

This was a cross-sectional survey of NPHIs.

METHODS

A web-based survey questionnaire was disseminated to 110 NPHIs in 95 countries between July and August 2022. Data were descriptively analysed, stratified by World Health Organization region, World Bank Income Group, and self-reported Integrated Disease Surveillance (IDS) maturity status.

RESULTS

Sixty-five NPHIs responded. Systems exist to monitor notifiable diseases and vaccination coverage, but less so for private, pharmaceutical, and food safety sectors. While Ministries of Health usually lead surveillance, in many countries, NPHIs are also involved. Most countries report having partially developed IDS. Surveillance data are frequently inaccessible to the lead public health agency and seldomly integrated into a national public health surveillance system. Common challenges to establishing IDS include information technology system issues, financial constraints, data sharing and ownership limitations, workforce capacity gaps, and data availability.

CONCLUSIONS

Public health surveillance systems across the globe, although built on similar principles, are at different levels of maturity but face similar developmental challenges. Leadership, ownership and governance, supporting legal mandates and regulations, as well as adherence to mandates, and enforcement of regulations are critical components of effective surveillance. In many countries, NPHIs play a significant role in integrated disease surveillance.

The French national Global Burden of Disease (GBD) evaluation project

As in many countries, there is an urgent need to prioritize the issues in public health care and prevention in France. The French GBD project aims to offer a unique set of combined morbidity and mortality estimates to inform health policy makers in France, at the national level. However, because of the variability in health status and risk factors across geographical areas, policy makers need comparable estimates at the regional and local levels to target specific populations and to implement actions to improve health. Besides, although the accuracy of the indicators provided by the GBD has not been evaluated in the French context, it would be likely improved by enhancing and enriching the French data used as input.

The French national health data system is one of the largest healthcare claims database in Europe. Based on these data, the French National Health Insurance (Cnam) and Santé publique France (SpFrance), in collaboration with clinicians and researchers, have developed a set of algorithms to identify diseases based on health care reimbursements, which could improve GBD estimates.

Cnam and SpFrance both contribute to the definition, prioritization and evaluation of health policies in France and have therefore decided to pool their strengths and mutualize their resources to build a common rationale and provide consistent French Burden of Diseases estimates. A collaboration with the Institute of Health Metrics and Evaluation (IHME) has also been initiated, to allow Cnam and SpFrance benefiting from IHME's infrastructure and expertise and together seek to improve the estimates of the indicators using comparable methods at local and national levels, and consistent with the overall Global Burden of Disease project.

Finally, beyond the ongoing production of the GBD metrics, another objective is the knowledge transfer to Cnam and SpFrance as learning organizations.

The project has started with a framework between the three parties and the expression of interest.

A preliminary estimation of the reproduction ratio for new influenza A(H1N1) from the outbreak in Mexico, March-April 2009

As of 12 May 2009, 5,251 cases of the new influenza A(H1N1) have been officially reported to the World Health Organization (WHO) from 30 countries, with most of the identified cases exported from Mexico where a local epidemic has been going on for the last two months. Sustained human-to-human transmission is necessary to trigger influenza pandemic and estimating the reproduction ratio (average number of secondary cases per primary case) is necessary for forecasting the spread of infection. We use two methods to estimate the reproduction ratio from the epidemic curve in Mexico using three plausible generation intervals (the time between primary and secondary case infection). As expected, the reproduction ratio estimates were highly sensitive to assumptions regarding the generation interval, which remains to be estimated for the current epidemic. Here, we suggest that the reproduction ratio was less than 2.2 - 3.1 in Mexico, depending on the generation interval. Monitoring and updating the reproduction ratio estimate as the epidemic spreads outside Mexico into different settings should remain a priority for assessing the situation and helping to plan public health interventions.

International travels and fever screening during epidemics: a literature review on the effectiveness and potential use of non-contact infrared thermometers

Several countries plan to introduce non-contact infrared thermometers (NCIT) at international airports in order to detect febrile passengers, thus to delay the introduction of a novel influenza strain. We reviewed the existing studies on fever screening by NCIT to estimate their efficacy under the hypothesis of pandemic influenza. Three Severe Acute Respiratory Syndrome (SARS) or dengue fever interventions in airports were excluded because of insufficient information. Six fever screening studies in other gathering areas, mainly hospitals, were included (N= 176 to 72,327 persons; fever prevalence= 1.2% to 16.9%). Sensitivity varied from 4.0% to 89.6%, specificity from 75.4% to 99.6%, positive predictive value (PPV) from 0.9% to 76.0% and negative predictive value (NPV) from 86.1% to 99.7%. When we fixed fever prevalence at 1% in all studies to allow comparisons, the derived PPV varied from 3.5% to 65.4% and NPV was >=99%. The low PPV suggests limited efficacy of NCIT to detect symptomatic passengers at the early stages of a pandemic influenza, when fever prevalence among passengers would be =<1%. External factors can also impair the screening strategy: passengers can hide their symptoms or cross borders before symptoms occur. These limits should be considered when setting up border control measures to delay the pandemic progression.

International travels and fever screening during epidemics: a literature review on the effectiveness and potential use of non-contact infrared thermometers

Several countries plan to introduce non-contact infrared thermometers (NCIT) at international airports in order to detect febrile passengers, thus to delay the introduction of a novel influenza strain. We reviewed the existing studies on fever screening by NCIT to estimate their efficacy under the hypothesis of pandemic influenza. Three Severe Acute Respiratory Syndrome (SARS) or dengue fever interventions in airports were excluded because of insufficient information. Six fever screening studies in other gathering areas, mainly hospitals, were included (N= 176 to 72,327 persons; fever prevalence= 1.2% to 16.9%). Sensitivity varied from 4.0% to 89.6%, specificity from 75.4% to 99.6%, positive predictive value (PPV) from 0.9% to 76.0% and negative predictive value (NPV) from 86.1% to 99.7%. When we fixed fever prevalence at 1% in all studies to allow comparisons, the derived PPV varied from 3.5% to 65.4% and NPV was >or=99%. The low PPV suggests limited efficacy of NCIT to detect symptomatic passengers at the early stages of a pandemic influenza, when fever prevalence among passengers would be =or<1%. External factors can also impair the screening strategy: passengers can hide their symptoms or cross borders before symptoms occur. These limits should be considered when setting up border control measures to delay the pandemic progression.

Reported cases of congenital syphilis in the French national hospital database

In France, the resurgence of syphilis infection since the beginning of the 2000s, with cases reported among women of reproductive age is a reason for concern considering the possible occurrence of congenital syphilis (CS). Using the French national private and public hospital database, we investigated the number of children with a diagnosis of CS born in France in 2004. Six cases less than one year old were identified as probable CS in the database. Two of these cases were adopted children from outside Europe, whereas the other four were born in France. The mothers of these last four infants tested positive for syphilis during the third trimester of pregnancy, two of them during premature delivery. Three of the four mothers were born abroad. Specific socio-cultural conditions may have been responsible for a lack of antenatal care responsible for the disease. Since CS is a preventable disease and the treatment of syphilis infection is cost-effective, we conclude that surveillance of CS cases and assessment of syphilis screening practises during pregnancy should be performed to prevent the occurrence of CS cases in France.

Principles and uses of HIV incidence estimation from recent infection testing - a review

Since the 1990s, the development of laboratory-based methods has allowed to estimate incidence of human immunodeficiency virus (HIV) infections on single samples. The tests aim to differentiate recent from established HIV infection. Incidence estimates are obtained by using the relationship between prevalence, incidence and duration of recent infection. We describe the principle of the methods and typical uses of these tests to characterise recent infection and derive incidence. We discuss the challenges in interpreting estimates and we consider the implications for surveillance systems. Overall, these methods can add remarkable value to surveillance systems based on prevalence surveys as well as HIV case reporting. The assumptions that must be fulfilled to correctly interpret the estimates are mostly similar to those required in prevalence measurement. However, further research on the specific aspect of window period estimation is needed in order to generalise these methods in various population settings.

Four years of surveillance of recent HIV infections at country level, France, mid 2003 – 2006: Experience and perspectives

New systems of surveillance to better monitor the dynamics of HIV are needed. A national surveillance of new HIV diagnoses which included the collection of dried serum spots (DSS) to identify recent infections (<6 months) using an EIA-RI assay was implemented in 2003 in France. The collection of DSS is based on the voluntary participation by both patients and microbiologists. Multivariate analysis was used to identify factors associated with recent infection (RI). Between July 2003 and December 2006, 14,155 cases newly diagnosed for HIV were reported. A minority of patients refused the collection of DSS (3.3%) and the rate of participation of laboratories was 80%. The test was performed for 10,855 newly diagnosed HIV cases, the overall proportion of RI was 23.1% (95% CI, 22.3%-23.9%). The proportion of RI was higher among men who have sex with men (MSM) (42.8%) than among heterosexuals (16.3%). Among heterosexuals, it varied by current nationality: 27% among French versus 8.4% among Africans. The risk of RI was greater for MSM (aOR=1.8), those of French nationality (aOR=3.9), those with high-economic status (aOR=1.2), those tested after a risk exposure (aOR=1.4), those tested for HIV three or more times during their lifetime (aOR=2.5). The risk of RI decreased with age. A nation-wide implementation of RI monitoring is feasible. The information on RI is very useful for renewing prevention messages, particularly among population in which HIV transmission is on going, such as MSM.

Principles and uses of HIV incidence estimation from recent infection testing--a review

Since the 1990s, the development of laboratory-based methods has allowed to estimate incidence of human immunodeficiency virus (HIV) infections on single samples. The tests aim to differentiate recent from established HIV infection. Incidence estimates are obtained by using the relationship between prevalence, incidence and duration of recent infection. We describe the principle of the methods and typical uses of these tests to characterise recent infection and derive incidence. We discuss the challenges in interpreting estimates and we consider the implications for surveillance systems. Overall, these methods can add remarkable value to surveillance systems based on prevalence surveys as well as HIV case reporting.The assumptions that must be fulfilled to correctly interpret the estimates are mostly similar to those required in prevalence measurement. However, further research on the specific aspect of window period estimation is needed in order to generalise these methods in various population settings.

Stopping TB in Europe: some progress but still not there

Overview of the epidemiological situation in 2006. The latest available information from countries in the World Health Organization (WHO) European Region carries important signals about the tuberculosis (TB) situation in this part of the world [1]. The total number of TB cases reported in the Region was slightly lower in 2006 than in 2005 (422,830 versus 426,457), reflecting a decrease in three-fourths of the reporting countries. Most TB cases in 2006 (73%) were reported by 12 former Soviet Union republics in the East, 21% by the European Union and West (EU and West) and 6% by the remaining countries in the Balkans (Table 1; for the composition of geographical areas see Box). National TB notification rates ranged from 4 to 282 per 100,000 population. The total TB notification rate for the whole Region has increased very slightly between 2002 and 2006, from 46 to 48 cases per 100,000, although rates of previously untreated TB cases appear to be on the decrease in both the East and West (Figure 1). We describe the main epidemiological features of TB cases notified in each of the abovementioned areas using surveillance data reported by the countries themselves.

A large multi-pathogen waterborne community outbreak linked to faecal contamination of a groundwater system, France, 2000

A large waterborne outbreak of infection that occurred during August 2000 in a local community in France was investigated initially via a rapid survey of visits to local physicians. A retrospective cohort study was then conducted on a random cluster sample of residents. Of 709 residents interviewed, 202 (28.5%) were definite cases (at least three liquid stools/day or vomiting) and 62 (8.7%) were probable cases (less than three liquid stools/day or abdominal pain). Those who had drunk tap water had a three-fold increased risk for illness (95% CI 2.4-4.0). The risk increased with the amount of water consumed (chi-square trend: p < 0.0001). Bacteriological analyses of stools were performed for 35 patients and virological analyses for 24 patients. Campylobacter coli, group A rotavirus and norovirus were detected in 31.5%, 71.0% and 21% of samples, respectively. An extensive environmental investigation concluded that a groundwater source to this community had probably been contaminated by agricultural run-off, and a failure in the chlorination system was identified. This is the first documented waterborne outbreak of infection involving human C. coli infections. A better understanding of the factors influencing campylobacter transmission between hosts is required.

Eurosurveillance comes of age and moves to ECDC

Eurosurveillance was created in 1995 to support exchange and dissemination of authoritative scientific information within the part of public health community involved in the field of infectious disease surveillance and control, at a time when European surveillance networks were at an early stage of growth. Now part of a large network, the publication is entering a new stage: the editorial function will now be hosted at the European Centre for Disease Prevention and Control (ECDC) in Stockholm. This will strengthen the platform for the next stage in Eurosurveillance’s development as the major home of peer-reviewed European information on infectious disease surveillance and control.

Are there ‘new’ and ‘old’ ways to track infectious diseases hazards and outbreaks?

In May 2005 the World Health Assembly approved an innovative and ambitious revision of the International Health Regulations, known as IHR(2005), in order to detect and control, in a timely manner, all public health events that may have a serious international impact. It represents a dramatic move from administrative notification by Member States (MS) to the World Health Organization (WHO) of cases of a limited list of diseases to a systematic analysis of health events of international concern, infectious or not [1]. The analysis of the public health events will take into account severity, unexpectedness, potential for international spread, and interference with international movement of people and goods. National focal points are to be identified in each MS to interact with WHO. The philosophy behind the new IHR is to promote early dialogue between MS and WHO, leading to early mutual risk assessment of events which may not necessarily have to be notified, depending on the results of the assessment and measures taken. WHO can also use informal sources to detect earlier events of international concern and then, together with the national focal point, conduct verification, risk assessment and implement appropriate measures.

Emergence of Clostridium difficile toxinotype III, PCR-ribotype 027-associated disease, France, 2006

On 27 March 2006, the Institut de Veille Sanitaire (InVS) was alerted to a cluster of Clostridium difficile associated disease (CDAD) in a healthcare facility in northern France

Rectal lymphogranuloma venereum surveillance in France 2004-2005

Lymphogranuloma venereum (LGV) is a sexually transmitted infection (STI) caused by Chlamydia trachomatis strains belonging to the L1, L2 or L3 genotype. An alert about an outbreak of LGV among MSM in the Netherlands was published in January 2004. The first cases of rectal LGV in France were retrospectively diagnosed in March 2004 and sentinel surveillance for LGV was implemented in April 2004. Most of the participating centres were located in the cities of Paris and Bordeaux. Only confirmed rectal LGV cases were included in the surveillance. Rectal specimens from men that were found to be positive for C trachomatis by PCR were sent to the National Reference Centre for Chlamydia infection for genotyping. Simple epidemiological data provided by clinicians and genotyping results were sent to the Institut de Veille Sanitaire (InVS) where data were anonymously recorded. A total of 328 C. trachomatis rectal strains isolated in men were genotyped by the end of December 2005. Of these, 244 (74%) were LGV strains belonging to the L2 genotype. No L1 or L3 C. trachomatis genotype was found. Diagnosis was made retrospectively for 46 cases. The median age of patients with LGV was 39 years. HIV status was known for 96 patients: 82/96 (85%) were HIV-infected. Most LGV cases were diagnosed in the Paris area (92%). Among the remaining 26% C. trachomatis strains, genotypes Da and G were the most frequent. As with syphilis in recent years, the emergence of LGV in Europe is mainly affecting HIV-infected MSM. The screening and treatment of STIs should be included in the clinical follow-up of all HIV-infected MSM.

Rectal lymphogranuloma venereum surveillance in France 2004-2005

Lymphogranuloma venereum (LGV) is a sexually transmitted infection (STI) caused by Chlamydia trachomatis strains belonging to the L1, L2 or L3 genotype. An alert about an outbreak of LGV among MSM in the Netherlands was published in January 2004. The first cases of rectal LGV in France were retrospectively diagnosed in March 2004 and sentinel surveillance for LGV was implemented in April 2004. Most of the participating centres were located in the cities of Paris and Bordeaux. Only confirmed rectal LGV cases were included in the surveillance. Rectal specimens from men that were found to be positive for C trachomatis by PCR were sent to the National Reference Centre for Chlamydia infection for genotyping. Simple epidemiological data provided by clinicians and genotyping results were sent to the Institut de Veille Sanitaire (InVS) where data were anonymously recorded. A total of 328 C. trachomatis rectal strains isolated in men were genotyped by the end of December 2005. Of these, 244 (74%) were LGV strains belonging to the L2 genotype. No L1 or L3 C. trachomatis genotype was found. Diagnosis was made retrospectively for 46 cases. The median age of patients with LGV was 39 years. HIV status was known for 96 patients: 82/96 (85%) were HIV-infected. Most LGV cases were diagnosed in the Paris area (92%). Among the remaining 26% C. trachomatis strains, genotypes Da and G were the most frequent. As with syphilis in recent years, the emergence of LGV in Europe is mainly affecting HIV-infected MSM. The screening and treatment of STIs should be included in the clinical follow-up of all HIV-infected MSM.

[Incidence and risk factors of HCV infection in a cohort of intravenous drug users in the North and East of France]

BACKGROUND

In order to evaluate the incidence and risk factors of infection by hepatitis C virus (HCV) among intravenous drug users we conducted a prospective cohort study of HCV and HIV negative IVDU in the North and East of France.

METHODS

Two hundred and thirty-one IVDU who had injected drug at least once in their lifetime and were negative for anti-HCV and anti-HIV were followed-up every three months over a 12-month period. Serum anti-HCV and anti-HIV antibodies were tested at inclusion in the study and at the end of the follow-up. Data on injection practices and behaviours were collected at inclusion and at each visit, and a test for anti-HCV antibodies was performed on a saliva sample. When this proved positive, an ELISA test for serum anti-HCV antibodies was carried out.

RESULTS

Of the 231 participants included, 165 (71.4%) underwent a final HCV and HIV serum test. The incidence was nil for HIV infection and 9% (95% CI: 4.6-13.4) person-years for HCV infection. Among IVDU who injected at least once during the last 6 months HCV infection incidence was 11% (95% CI: 4.7-17.1) person-years. The multivariate analysis carried out on the inclusion data found female sex alone to be an independent predictive factor of HCV seroconversion. In a Cox proportional hazard multivariate analysis that took into account time-dependent exposures and covariates, we found that syringe and cotton sharing were, after adjusting for other covariates, the only independent predictive factors of HCV seroconversion: hazard ratio: 6.3 [corrected] (95% CI: 1.1-35.4; [corrected] p<0.05) and 16.4 (95% CI: 1.4-190.6; [corrected] p<0.05), respectively.

CONCLUSION

The transmission of the HCV virus persists among French IVDU despite an ongoing national harm reduction program. Injecting material and cotton sharing are the two major determinants of transmission in this cohort.

[Modes of hepatitis C virus transmission: methodological approaches]

Since the mid-1990s, hepatitis C virus (HCV) transmission through blood transfusion has become very rare in western countries. Better understanding of the current modes of transmission is needed. However, risk factors have been mainly estimated on prevalent HCV infections. In this paper we describe the methods of the main case-control studies and their contribution to the knowledge on modes of HCV transmission. We also report the results of a case-control study of incident HCV infections recently carried out in France which confirms the continuing major role of IV drug use and suggests that transmission related to invasive care remained a potential source of new HCV infection between 1995 and 2001.

[Limited impact of the harm-reduction policy on HCV among drug-users. The ANRS-Coquelicot survey example]

BACKGROUND

In France, a harm-reduction policy was implemented in the late 1980s with the aim of reducing the prevalence of HIV and hepatitis C virus infection among drug users. The ANRS-Coquelicot survey was designed to measure the prevalence of HIV and HCV infection among drug users, and to examine determinants of at-risk behaviors.

METHODS

In 2002, information was collected from 166 drug users recruited in all types of services specializing in drug use and harm reduction in Marseille, France. Self-reported HIV and HCV serostatus was compared with the results of serological tests done on capillary blood collected on filter paper.

RESULTS

The self-reported and biologically documented prevalence rates of HIV infection were identical (22 %). In contrast, the self-reported prevalence of HCV infection was 52 %, while the biologically documented prevalence was 73 %. Overall, 30 % of HCV-infected drug users were unaware of their status. Forty-four per cent of drug users under 30 years of age were HCV-seropositive, suggesting that they had been infected early during drug use.

CONCLUSION

The harm-reduction policy seems to have had a marked impact on HIV transmission among drug users, but a much more limited impact on HCV transmission.

[Risk factors for hepatitis C virus transmission to Health Care Workers after occupational exposure: a European case-control study]

BACKGROUND

Factors that influence the risk for HCV infection after occupational exposure to hepatitis C virus (HCV) have not yet been determined. The objective of this study was to assess potential risk factors for Hepatitis C seroconversion after occupational exposure to HCV.

METHODS

We conducted a European matched case-control study from 01/01/1991 through 31/12/ 2002. Cases were Health Care Workers (HCWs) who were HCV seronegative at the time of exposure, sustained a documented exposure to HCV, and present documented HCV seroconversion temporally associated with the exposure. Controls-HCWs had a documented exposure to HCV, were HCV seronegative at the time of exposure, and remained so at least 6 months later. Controls were matched to cases for the center and the time period of the exposure occurrence.

RESULTS

60 cases and 204 controls were included. All cases were exposed to HCV-infected materials through percutaneous injuries. Those for whom information was available (61.6%) were exposed to viremic source patients. Multivariate conditional logistic regression analysis, in which HCV viral load was not introduced because of missing values, identified needle placed in the source patient's vein or artery (Odds Ratio [OR]=100.1; 95% Confidence Interval [CI]=7.3-1365.7), deep injury (OR=155.2; 95%CI=7.1-3417.2), and HCW's gender (M vs. F: OR=3.1; 95%CI=1.0-10.0) as risk factors for HCV infection. In univariate unmatched analysis the risk of HCV transmission was increased 11-fold (C195%=1.1-114.1) in HCWs exposed to sources with a viral load>6 log10 copies/mL when compared to sources with a HCV viral load<4 log10 copies/mL.

CONCLUSION

The risk of HCV transmission after percutaneous exposure increases with a larger volume of blood, and, a higher titer of HCV in the source patient's blood. The role of HCW's gender need to be further investigated. The results of this study have important implications for counselling and follow-up of HCWs after exposure.

World TB day: European countries report over 400,000 tuberculosis cases in 2004

In 2004, 414 163 tuberculosis cases were notified by 51 of the 52 countries of the World Health Organization European Region, representing 8% of notifications to WHO worldwide in the same year. Seventy per cent of all TB cases in the region were in the 12 countries of the Former Soviet Union

Absence of infection in asymptomatic contacts of index SARS case in France

The first case of severe acute respiratory syndrome (SARS) in France was diagnosed in March 2003. We conducted a serological survey to assess whether or not asymptomatic persons who had been in contact with this patient during his infectious stage had been infected. They were interviewed and asked to provide a blood sample for SARS coronavirus immunoglobulin G antibody testing. Despite the likely high infectivity of the SARS patient, no asymptomatic SARS infection was found in any of the 37 contacts included. These findings support a SARS case definition that is essentially based on clinical and epidemiological assessment, should SARS re-emerge.

Absence of infection in asymptomatic contacts of index SARS case in France

The first case of severe acute respiratory syndrome (SARS) in France was diagnosed in March 2003. We conducted a serological survey to assess whether or not asymptomatic persons who had been in contact with this patient during his infectious stage had been infected. They were interviewed and asked to provide a blood sample for SARS coronavirus immunoglobulin G antibody testing. Despite the likely high infectivity of the SARS patient, no asymptomatic SARS infection was found in any of the 37 contacts included. These findings support a SARS case definition that is essentially based on clinical and epidemiological assessment, should SARS re-emerge.

Association between indicators of cattle density and incidence of paediatric haemolytic-uraemic syndrome (HUS) in children under 15 years of age in France between 1996 and 2001: an ecological study

Over the past years Shiga-like toxin-producing Escherichia coli (STEC) O157:H7 emerged as an important cause of severe gastrointestinal illnesses and haemolytic-uraemic syndrome (HUS) with up to 10% of children infected with STEC developing HUS. We conducted a geographical ecological study using the district as the statistical unit. For each district, we estimated the incidence of HUS among children <15 years for the period 1996-2001 from national HUS surveillance data and data obtained on cattle density. We used multivariate Poisson regression to quantify the relation, adjusted for covariates, between paediatric HUS incidence and exposure to cattle. In univariate analysis, a positive association was observed between several cattle-density indicators and HUS incidence. In multivariate analysis, HUS paediatric incidence was associated with dairy cattle density and the ratio of calves to children <15 years (P<0.001). Our findings are consistent with previous studies in other countries and support the recommendation to limit exposure of children to dairy cattle and manure to reduce the risk of STEC infection.

Risk factors for hepatitis C virus transmission to health care workers after occupational exposure: a European case-control study

BACKGROUND

Additional studies are required to identify risk factors for hepatitis C virus (HCV) transmission to health care workers after occupational exposure to HCV.

METHODS

We conducted a matched case-control study in 5 European countries from 1 January 1991 through 31 December 2002. Case patients were health care workers who experienced seroconversion after percutaneous or mucocutaneous exposure to HCV. Control subjects were HCV-exposed health care workers who did not experience seroconversion and were matched with case patients for center and period of exposure.

RESULTS

Sixty case patients and 204 control subjects were included in the study. All case patients were exposed to HCV-infected fluids through percutaneous injuries. The 37 case patients for whom information was available were exposed to viremic source patients. As risk factors for HCV infection, multivariate analysis identified needle placement in a source patient's vein or artery (odds ratio [OR], 100.1; 95% confidence interval [CI], 7.3-1365.7), deep injury (OR, 155.2; 95% CI, 7.1-3417.2), and sex of the health care worker (OR for male vs. female, 3.1; 95% CI, 1.0-10.0). Source patient HCV load was not introduced in the multivariate model. In unmatched univariate analysis, the risk of HCV transmission increased 11-fold for health care workers exposed to source patients with a viral load >6 log(10) copies/mL (95% CI, 1.1-114.1), compared with exposures to source patients with a viral load < or =4 log10 copies/mL.

CONCLUSION

In this study, HCV occupational transmission was found to occur after percutaneous exposures. The risk of HCV transmission after percutaneous exposure increased with deep injuries and procedures involving hollow-bore needle placement in the source patient's vein or artery. These results highlight the need for widespread adoption of needlestick-prevention devices in health care settings, together with other preventive measures.

Surveillance of listeria infections in Europe

In addition to the economic consequences and threats associated with outbreaks, listeriosis remains of great public health concern, as it has one of the highest case fatality rates of all the foodborne infections (20%-30%), and has common source epidemic potential. Changes in the way food is produced, distributed and stored have created the potential for diffuse and widespread outbreaks involving many countries. In 2002, a survey was carried out to assess the need for and the feasibility of a European network on listeria infections in humans. Data on surveillance systems and laboratory methods were collected through two postal surveys sent to the national Centres for communicable disease surveillance and to the listeria reference laboratories. Surveillance systems for listeria infections were in operation in 16 out of the 17 countries surveyed, and 16 countries had a national reference laboratory (NRL). All countries based their case definition of listeriosis on the isolation of Listeria monocytogenes. Fourteen NRLs performed at least one typing method on human strains. At least 13 countries already carried out or expressed willingness to carry out characterisation of isolates by pulsed field gel electrophoresis (PFGE) of L. monocytogenes strains isolated from human cases following a standard protocol. The participants concluded that there was a clear added value to having a European surveillance network for listeria infections, particularly for outbreak detection and investigation, and that a surveillance network based on the existing national surveillance systems was feasible.

Surveillance of listeria infections in Europe

In addition to the economic consequences and threats associated with outbreaks, listeriosis remains of great public health concern, as it has one of the highest case fatality rates of all the foodborne infections (20%-30%), and has common source epidemic potential. Changes in the way food is produced, distributed and stored have created the potential for diffuse and widespread outbreaks involving many countries. In 2002, a survey was carried out to assess the need for and the feasibility of a European network on listeria infections in humans. Data on surveillance systems and laboratory methods were collected through two postal surveys sent to the national Centres for communicable disease surveillance and to the listeria reference laboratories. Surveillance systems for listeria infections were in operation in 16 out of the 17 countries surveyed, and 16 countries had a national reference laboratory (NRL). All countries based their case definition of listeriosis on the isolation of Listeria monocytogenes. Fourteen NRLs performed at least one typing method on human strains. At least 13 countries already carried out or expressed willingness to carry out characterisation of isolates by pulsed field gel electrophoresis (PFGE) of L. monocytogenes strains isolated from human cases following a standard protocol. The participants concluded that there was a clear added value to having a European surveillance network for listeria infections, particularly for outbreak detection and investigation, and that a surveillance network based on the existing national surveillance systems was feasible.

Foodborne Infections in France

To quantify the impact of foodborne diseases on health, and set priorities for data collection, prevention and control of these diseases, we compiled and analyzed information from surveillance systems and other sources on the morbidity and mortality due to foodborne infectious diseases in mainland France in the last decade of the 20th century. Illness due to 13 bacteria, two viruses, and eight parasites were studied. The number of foodborne infections, hospitalizations, and deaths were estimated from multiple data sources. For each agent, several estimates were derived from the different sources. Estimates were ranked according to their plausibility, based on an assessment of the validity of the data source, and are presented as a "plausible interval" consisting of a low and high estimate. We estimate that these pathogens caused 10,200-17,800 hospitalizations per year. Salmonella is the most frequent cause (5,700-10,200 cases), followed by Campylobacter (2,600-3,500 cases) and Listeria (304 cases). Toxoplasmosis accounts for the majority of hospitalizations (426 cases) attributable to the studied parasitic infections. The number of deaths related to foodborne infection was estimated between 228 and 691. Bacterial pathogens account for the majority (191 to 652) of deaths of which 92 to 535 are attributable to salmonellosis, ranking as the first cause of death, and 78 to listeriosis, the second cause. Salmonella, Campylobacter, and Listeria are the main causes of severe foodborne illness in France. For several pathogens, data are insufficient to derive exact estimates of the disease burden. Nevertheless, it has been possible to derive plausible estimates for the majority, and to rank them according to their impact on public health.

Acute hepatitis C infection in HIV positive men who have sex with men in Paris, France, 2001-2004

In mid-2004, three Parisian hospital wards informed the Institut de veille sanitaire of recent acute hepatitis C in HIV-infected (HIV+) men who had sex with men (MSM). These cases for whom none of the usual bloodborne routes for hepatitis C (HCV) transmission was found, reported having had unprotected sex. In October 2004, we conducted a retrospective investigation in Parisian hospital wards to explore HCV modes of transmission in recent acute hepatitis C in HIV+ MSM. Patient demographics, clinical and biological status of HIV infection, reasons for HCV testing, sexual behaviour and risk factors for HCV transmission within the 6 months before hepatitis onset were collected from medical records. An anonymous self-administered questionnaire on sexual behaviour within the six months before hepatitis onset was also offered to all cases. We identified 29 cases of acute hepatitis C in HIV+ MSM with onset from April 2001 to October 2004. HIV infection was asymptomatic for 76%. Median age at hepatitis C onset was 40 (28-54) years. In all records, were noted unprotected anal sex, fisting in 21% and a concomitant sexually transmitted infection (STI) in 41%. Median time between HIV diagnosis and HCV infection was 6.5 years (0-22). From the 11 self-administered questionnaires completed, 10 reported an STI, 8 'hard' sexual practices, 6 bleeding during sex and 5 fisting. HCV transmission probably occurred through bleeding during unprotected traumatic anal sex among HIV+ MSM and may be facilitated by STI mucosal lesions. This report stresses the continuous need to strongly advocate safer sex to MSM.

Preliminary results from the new HIV surveillance system in France

In addition to AIDS surveillance, data on HIV infection are necessary to better follow the dynamics of the epidemic. We report the first results of France's mandatory anonymous HIV notification system, which is linked to a virological surveillance of recent HIV infections and of circulating HIV types, groups and subtypes. HIV notifications are initiated by microbiologists who create an anonymous code of patient's identity. Clinicians complete the notification form with epidemiological and clinical data. Notifications are sent to the local health authorities and passed to the Institut de Veille Sanitaire (InVS). Laboratories voluntarily send sera from newly diagnosed HIV infected persons on dried blood spots to the national HIV reference laboratory where an immunoassay for recent infection (< or = 6 months) and a serotyping assay for the determination of group and subtype are done. The virological results are then merged at the InVS with the information from the mandatory reporting. Of the first 1301 new HIV diagnoses reported in 2003, 43% were in women, and overall, 53% were in heterosexuals, of whom 47% were of sub-Saharan African origin. MSM accounted for 36% of male notifications. A dried blood spot was available for 64% of new HIV diagnoses. Evidence of recent infection was found for 38%, ranging from 22% in IDUs to 58% in MSM. Twenty-six percent of infections in sub-Saharan migrants were recent infections. HIV-1 accounted for 98% of all notifications: 48% of these were non-B subtypes. The first results of the HIV notification system indicate that heterosexual transmission is the predominant mode of transmission and that persons originating from sub-Saharan Africa are particularly affected. Over half of infections shown to be recently acquired were in MSM; this may indicate an increased HIV incidence in this population.

Preliminary results from the new HIV surveillance system in France

In addition to AIDS surveillance, data on HIV infection are necessary to better follow the dynamics of the epidemic. We report the first results of France's mandatory anonymous HIV notification system, which is linked to a virological surveillance of recent HIV infections and of circulating HIV types, groups and subtypes. HIV notifications are initiated by microbiologists who create an anonymous code of patient's identity. Clinicians complete the notification form with epidemiological and clinical data. Notifications are sent to the local health authorities and passed to the Institut de Veille Sanitaire (InVS).

Incidence and risk factors of HCV and HIV infections in a cohort of intravenous drug users in the North and East of France

In order to evaluate the incidence and risk factors of infection by hepatitis C virus (HCV) among injecting drug users (IDUs), we conducted a prospective cohort study of HCV- and human immunodeficiency virus (HIV)-negative IDUs in the North and East of France. A total of 231 HCV and HIV IDUs who had injected drugs at least once in their lifetime were followed up every 3 months over a 12-month period. Serum anti-HCV and anti-HIV were tested at inclusion in the study and at the end of the follow-up. Data on injecting practices were collected at inclusion and at each visit. Of the 231 participants included, 165 (71.4%) underwent a final HCV and HIV serum test. The incidence was nil for HIV infection and 9/100 person-years (95% CI 4.6-13.4) for HCV infection. In a multivariable analysis, we found that syringe and cotton sharing were the only independent predictive factors of HCV seroconversion.

The use of the case-crossover design in a continuous common source food-borne outbreak

When applicable, case-crossover studies may be quicker and cheaper to complete than case-control studies. Because time is a major issue in outbreak investigations, we evaluated the interest of this design during a continuous common source food-borne outbreak of salmonellosis for which the vehicle (hamburgers) was also implicated by environmental and laboratory investigations. Seventeen of the 35 cases identified in the outbreak were included in the study according to the availability of menu records with detailed information on food consumed at each meal. Food exposures during a 3-day risk period before onset of illness were compared to those of a control time-interval of the same duration that preceded the risk period by two days. Seventy-seven per cent of the cases (13/17) had consumed hamburgers in the three days preceding onset of illness compared with 29% (5/17) during the control period (P = 0.04, odds ratio = 5, 95% CI: 1.1-46.9). In this investigation the case-crossover design proved to be a useful and efficient alternative to the case-control approach. However, further evaluation of this design in outbreak investigation is needed.

Le poids médico-économique des gastro-entérites aiguës de l’enfant : l’éclairage du Programme de Médicalisation des Systèmes d’Information (PMSI)

OBJECTIVES

To estimate the burden of hospitalized infectious gastroenteritis of children younger than 5 years of age and associated costs.

METHODS

We analyzed 1997 hospital discharges with a primary diagnosis of gastroenteritis or a secondary diagnosis of gastroenteritis with gastroenteritis symptoms or complications as primary diagnosis and compared the deaths with those of the national mortality data.

RESULTS

Gastroenteritis was associated with 51,125 hospitalizations which accounted for 11.4% of hospitalization discharges for this age group and an annual rate of 1,385 per 100,000 children <5-year-old. Most gastroenteritis (56%) were registered as "probably infectious", 36% as "viral" (43% of which were coded "rotavirus") and 8% as "bacterial" (of which 60% were coded "Salmonella"). The seasonal peak was winter for rotaviral, viral and "probably infectious" gastroenteritis, summer for those related to salmonellosis. Incidence increased inversely with age: 3606/100,000 infants <1-year-old, 257/100,000 4-year-old children. Complications (especially dehydration) were observed in 21% of viral gastroenteritis and 17% of bacterial gastroenteritis. At least, 14 deaths were found in both hospital discharge and mortality data. The mean duration of stay (3.2 days) was significantly higher in infants <1-year-old, viral etiology, association with complications or bronchiolitis. The costs of hospitalization could be estimated to 62 million Euros.

DISCUSSION

Our results are similar to those obtained in other developed countries. Despite variations in encoding the discharge reports, data has proven to be effective to describe national trends for this health event. Our study indicates that the public health burden and economic impact of prevention and control measures can be monitored through hospital discharge surveillance.

Repeat capture-recapture studies as part of the evaluation of the surveillance of Legionnaires' disease in France

We evaluated improvements made to the mandatory notification surveillance system for Legionnaires' disease in France by estimating its sensitivity in 1995 and 1998 using a repeat capture-recapture method. A case of Legionnaires' disease was defined as a person treated for pneumonia in whom legionella had been detected. Patient details were collected from (1) mandatory notifications; (2) the National Reference Centre for Legionella; (3) a postal survey of all hospital laboratories. The three sources were cross-matched and 715 individual cases were identified. A log-linear model, which included an interaction term between mandatory notifications and both the National Reference Centre and Laboratory sources, provided an estimated total of 1124 cases (95% CI 973-1275) in 1998, a twofold increase compared with 1995. The sensitivity of the surveillance system improved from 10% in 1995 to 33% (95% CI 29-38%) in 1998. Capture-recapture methods are important tools in the evaluation of surveillance systems.

Sporadic cases of community acquired legionnaires' disease: an ecological study to identify new sources of contamination

STUDY OBJECTIVE

To explore the relation between incidence of sporadic and community acquired legionnaires' disease and exposure to potentially contaminated industrial aerosols.

DESIGN

Geographical ecological approach using the postcode as the statistical unit. A multivariate Poisson regression model was used to model the relation between exposure to industrial aerosols and legionnaires' disease.

SETTING

Metropolitan France.

MAIN RESULTS

More than 1000 sources of industrial exposure (aerosol and plume of smoke) were identified in 42 French departments. After adjusting for confounding factors, there was a statistically increased incidence of legionnaires' disease in postcodes with plume of smoke in comparison with postcodes without (RR=1.45, 95% CI=1.12 to 1.87), and in postcodes with more than one aerosol in comparison with postcodes without (RR=1.37, 95% CI=1.04 to 1.79).

CONCLUSION

These findings highlight that any industrial systems generating water aerosols should be regarded as potential sources of contamination for legionnaires' disease.

[The capture-recapture applied to epidemiology: principles, limits and application]

By matching several sources of information coming from the same population, the capture-recapture method allows, if matches between sources can be identified, to estimate the number of cases not identified by any of the sources, the total number (N) of cases in the population and the sensitivity of each source. Used first in zoology and demography, this technique has been increasingly applied to epidemiology in the last two decades. However, six conditions need to be satisfied: all cases identified by each source are true cases; occurred during the time and the geographical area studied; the study population is closed; all matches are true matches; sources are independent and there is no heterogeneous catchability within sources. It is possible to assess and take into account dependence between sources when 3 or more sources are used, in particular by log linear modelling. However interactions of maximal order cannot be adjusted for. In case of a biased estimation because of the non respect of the conditions, it is recommended to apply a method of correction. The complete application of the methods is illustrated in the study of estimating the number of Salmonella infectious foodborne outbreak. As capture-recapture studies often use data collected for other purposes, this technique should be regarded as exploratory or be used to validate an estimate of a number of cases obtained by another method. It should not replace population sampling methods only because of its low cost. Otherwise it is a very informative approach to evaluate the sensitivity and representativeness of surveillance systems and registries.

[Food-borne infections: do we need further data collection for public health action and research]

The data needed for controlling and preventing food-borne infectious diseases relied so far on surveillance of the main food-borne infections (Salmonella and listeria infections) to follow trends over time and detect outbreak. However, this systematic continuous data collection was not always sensitive enough to timely detect community outbreaks and did not take into account sporadic cases of food-borne infections which represent the majority of patients (such as Campylobacter infection for example). Therefore, the true burden of food-borne infections, including morbidity, mortality and the social and economic cost could not be assessed. As the issue of food-borne infections got more social attention, the need of further epidemiological data has increased including the implementation of large population studies (active surveillance and follow up studies) associated with analytical studies in the United States (Foodnet) and in some European countries (United Kingdom, The Netherlands, Denmark.). Meanwhile surveillance and detection of outbreaks have substantially improved through the use of new typing scheme, particularly those based on molecular techniques. Their routine use, now, allows an early identification of the clonal spread of food-borne bacteria. The application of automatic detection algorithm to surveillance data base has also improved the performance of outbreak detection and changes of trends. Furthermore, food-borne infection surveillance has become European which allows, by pooling of national database, to identify emergence that did not get noticed in any country. To foster the prevention of sporadic cases, the use of analytical epidemiology has become more and more frequent and has improved the knowledge of food vehicles and risk factors. The risk assessment approach has also been applied to the microbial contamination of food to answer to the increasing needs of expertise, particularly at the international level. This approach, however, needs further methodological development and the collection of extra information on the food chain. Last, but not the least, a wider public health research approach must also be considered, particularly on the social perception of food-borne risks and the cost-effectiveness analysis of the prevention measures that are taken.

Two consecutive nationwide outbreaks of Listeriosis in France, October 1999-February 2000

In France, listeriosis surveillance is based on mandatory notification of all culture-confirmed cases, with systematic typing of isolates and routine collection of the patient's food history. From October 1999 to March 2000, two outbreaks of listeriosis were detected through this enhanced surveillance system. In outbreak 1, analysis of the food histories of cases suggested brand X "rillettes," a pâté-like meat product, as the vehicle of infection, and the outbreak strain of Listeria monocytogenes was subsequently isolated from the incriminated rillettes. In outbreak 2, a case-control study showed that consumption of jellied pork tongue was strongly associated with infection with the outbreak strain (odds ratio = 75.5, 95% confidence interval: 4.7, 1,216.0). However, trace-back results did not permit incrimination of any particular manufacturer of jellied pork tongue, and the outbreak strain was not isolated from the incriminated food or from any production sites. Consumption of jellied pork tongue was discouraged on epidemiologic evidence alone. The consecutive occurrence of these two outbreaks confirms the epidemic potential of listeriosis, even in a context of decreasing incidence, and underlines the importance of timely case-reporting and systematic typing of human L. monocytogenes strains to allow early detection and separate investigation of different clusters.

Hepatitis C in a ward for cystic fibrosis and diabetic patients: possible transmission by spring-loaded finger-stick devices for self-monitoring of capillary blood glucose

OBJECTIVE

To identify the routes of transmission in a nosocomial outbreak of hepatitis C virus (HCV) infection.

DESIGN

Epidemiological investigation, including screening for HCV of hospitalized patients, and a retrospective cohort study, review of hygiene and medical practices, and molecular comparison of HCV isolates.

SETTING

A specialized care unit for cystic fibrosis (CF) and diabetic patients at an acute-care facility in the south of France.

RESULTS

Of the 57 CF patients (age in 1995: 2-28 years), 38 (66.7%) were tested and 22 (57.9%) were anti-HCV positive. Eight (50%) of 16 patients with anti-HCV antibody tested by polymerase chain reaction were viremic. No patients had received blood products or had any history of intravenous drug use. All 18 (100%) patients with CF who had ever undergone self-monitoring of capillary blood glucose in the unit were anti-HCV positive, compared to 4 (20%) of 20 who had not (relative risk, 5.0; 95% confidence interval, 2.1-12.0). Seventy (39.5%) of the patients with diabetes were screened for anti-HCV; 12 (18.8%) tested positive, with 3 (25%) positive for HCV-RNA. Patients with diabetes had routine capillary blood glucose monitoring while hospitalized and shared with CF patients the same spring-triggered devices for capillary blood glucose monitoring. The disposable platform of the devices was not changed between patient use. All HCV isolates belonged to the type 1, subtype b, and phylogenetic analysis showed a close homology by sequencing of NS5b and E2/HVR regions.

CONCLUSION

As reported earlier for the hepatitis B virus, shared spring-triggered devices for capillary blood glucose monitoring by finger puncture may transmit HCV. Strict application of Standard Precautions procedures is warranted in any healthcare setting.

[Meningococcal W135 infection epidemics associated with pilgrimage to Mecca in 2000]

OBJECTIVES

On April 3 and 7, 2000, four cases of Neisseria meningitidis serogroup W135 infection were diagnosed in France in Raj pilgrims and their close relatives. Two cases were fatal. Due to the rarity of this strain in France, a strain belonging to a clonal complex implicated in several epidemics in Europe and North America, and it high mortality observed, The French General Direction of Heal issued recommendations on April 8th for rifampicin chemotherapy for all pilgrims and relatives living in their home. The national disease watch (Institut de Veille Sanitaire, InVS) conducted an investigation to describe the epidemic and follow the diffusion of the strain in the population and assess the impact of preventive measures taken as well as need for other specific measures.

METHODS

A case was considered to be confirmed when the strain isolated from usually sterile media after March 22 was found to be identical to the epidemic strain (W135, 2a: P1-2.5--clonal complex ET37). A case was considered probable when a pilgrim or in a person in contact with a pilgrim had clinical meningitis (purulent cerebrospinal fluid or purpura fulminans) or when the identified strain was in the W135 serogroup but could not be further identified. A standardized questionnaire developed in collaboration with the European countries concerned by the epidemic was filled out.

RESULTS

By November 20, 2000, 25 confirmed and 2 probable cases were identified; 85% of the cases occurred during the first 7 weeks of the epidemic. Mortality was 18%. Patients aged over 50 years accounted for 66% of the cases (6/9) occurring before April 9, 2000 and 17% of the cases (3/18) observed after this data. Four patients had single-joint arthritis. No cluster cases could be identified. Four cases occurred among 19,100 pilgrims (attack rate 21/100,000), 9 among persons living with pilgrims, 7 among subjects in direct contact with pilgrims but not living with them, and 7 among persons who had no identifiable contact with pilgrims. These last 7 cases occurred after the 3rd week of the epidemic. No cases occurred among persons who had taken rifampicin chemoprophylaxis. Eighteen cases occurred after diffusion of the prophylaxis recommendations including 5 in a population directly concerned by the recommendations.

CONCLUSIONS

These data suggest that the epidemic strain is not different from other strains in terms of virulence and transmissibility. Eight months after the Raj, the number of cases related to the epidemic remained limited in France. The characteristics of the most recent cases do however suggest an epidemic clone persists in the general population. The Direction of Health recommends vaccination using the quadrivalent A,C,W135,Y vaccine for the 2001 Raj.

Vaccine preventable diseases: a regional surveillance can help improve data comparability between countries

The way that surveillance of a given disease is undertaken in European countries varies greatly. Each study that has been undertaken on this subject so far has come to this conclusion, the variation between countries being related to many factors among which the organisation of the health care delivery plays a major role. This rule applies to vaccine preventable diseases and vaccine coverage surveillance as this Eurosurveillance issue shows. However, as the surveys undertaken for measles and pertussis indicate, there is a lot of common information gathered by each EU member state for both diseases. Therefore the definition of a minimal data set of pertinent variables common to most countries may be defined and is a way to initiate common EU data base. Whether this will be enough to effectively monitor timeliness and to compare the incidence in countries with different immunisation strategies and coverage needs to be further evaluated.

Effect of prevention measures on incidence of human listeriosis, France, 1987-1997

To assess the impact of preventive measures by the food industry, we analyzed food monitoring data as well as trends in the incidence of listeriosis estimated through three independent sources: the National Reference Center of Listeriosis; a laboratory-based active surveillance network; and two consecutive nationwide surveys of public hospital laboratories. From 1987 to 1997, the incidence of listeriosis decreased by an estimated 68%. A substantial reduction in the proportion of Listeria monocytogenes-contaminated products was observed at the retail level. The temporal relationship between prevention measures by the food industry, reduction in L. monocytogenes-contaminated foodstuffs, and reduction in listeriosis incidence suggests a causal relationship and indicates that a substantial part of the reduction in illness is related to prevention efforts.

Investigation of concurrent outbreaks of gastroenteritis and typhoid fever following a party on a floating restaurant, France, March 1998

A retrospective cohort study was carried out to investigate concurrent outbreaks of gastroenteritis and typhoid fever that occurred among guests of a supper on a floating restaurant in France in March 1998. A total of 133 guests (attack rate = 90%) reported gastroenteritis within 12 days of the supper. Twenty-seven guests developed typhoid fever (attack rate = 18%) of whom 15 were confirmed by stool or blood culture. All patients with typhoid fever had had an initial gastroenteritis. The results suggest that the same food items served during the supper, chicken and rice, were the vehicles of both gastroenteritis and typhoid fever, but the authors could not determine the specific source of infection. Initial gastroenteritis has been described as a clinical manifestation of typhoid fever but whether or not these two syndromes (gastroenteritis and typhoid fever) were due to the same etiology remains unclear in this outbreak.

Risk factors for the occurrence of sporadic Salmonella enterica serotype typhimurium infections in children in France: a national case-control study

To determine risk factors for the occurrence of sporadic Salmonella typhimurium infections among children in France, we conducted a matched case-control study. Cases were identified between 15 June and 30 September 1996. We interviewed 101 pairs of case patients and control subjects, matched for age and place of residence. The risk of illness was greater for children who ate undercooked ground beef than for those who did not (odds ratio [OR], 5.0; 95% confidence interval [CI], 1.9-13.1). Case patients were more likely than control subjects to have taken antibiotics during the month before onset of disease (OR, 2.2; 95% CI, 1.0-4.9). Case patients <5 years of age were more likely to have been in contact with a household member with diarrhea 3-10 days before onset (P=.05). Consumption of undercooked ground beef is a risk factor for the sporadic occurrence of S. typhimurium infection among children, and antibiotics may facilitate the occurrence of illness. The possibility of person-to-person transmission among young children needs to be considered.

How many foodborne outbreaks of Salmonella infection occurred in France in 1995? Application of the capture-recapture method to three surveillance systems

Despite control measures, foodborne outbreaks of non-typhi Salmonella infection continue to occur in developed countries. The authors aimed to assess the number of foodborne Salmonella outbreaks that occurred in France in 1995 using a capture-recapture approach. Data from three sources--the National Public Health Network (NPHN), the Ministry of Agriculture (MA), which receives mandatory notification, and the National Salmonella and Shigella Reference Center (NRC)-were collected. Matching algorithms permitted identification of matched outbreaks. The total number of outbreaks was estimated by log-linear modeling taking into account source dependencies and the variable catchability. The final estimate was adjusted for the positive predictive value (66%) of the NRC case definition. The dependence between the NPHN and the MA was also evaluated by means of a qualitative survey. A total of 716 foodborne Salmonella outbreaks were reported to the three sources, and 108 matches were identified. The best-fitting model, taking into account a positive dependence between the NPHN and MA sources, gave an estimate of 757 outbreaks. The sensitivity was 15% for the NPHN, 10% for the MA, and 50% for the NRC. In France, routine mandatory reporting of foodborne Salmonella outbreaks is very incomplete, and it is not representative of the serotype and the type of outbreak.

Risk factors of acute diarrhoea in summer--a nation-wide French case-control study

The aim of this study was to identify risk factors for acute diarrhoea (AD) during the summer in France. A matched case-control study was conducted at a national level among patients of 500 general practitioners (GPs). From July to September 1996, 468 case-control pairs were included. Cases were more likely than controls (i) to live away from their main residence (OR 3.0; 95% CI 1.6-5.7), (ii) to have returned from a country at high risk of AD (OR 4.6; CI 0.9-23.1), and (iii) to have been in contact with a case of AD (OR 2.0; CI 1.3-3.1). A significantly decreased risk of AD was found for consumption of well-cooked chicken (OR 0.5; CI 0.3-0.8) and raw or undercooked home-made egg-containing products (OR 0.6; CI 0.4-0.8). These findings suggest that travel to high-risk areas, or travel within France, and being in contact with a case of AD, are risk factors for the occurrence of AD in summer in France.