High Proportion of Asymptomatic Infections in an Outbreak of Hepatitis E Associated With a Spit-Roasted Piglet, France, 2013.

BACKGROUND: On 11 December 2013, 3 clustered cases of hepatitis E were reported on a French coastal island. Individuals had taken part in a wedding meal that included a spit-roasted piglet. The piglet had been stuffed with a raw stuffing partly made from the liver. Investigations were carried out to identify the vehicle of contamination and evaluate the dispersion of the hepatitis E virus (HEV) in the environment. METHODS: A questionnaire was administered to 98 wedding participants who were asked to give a blood sample. Cases were identified by reverse transcription-polymerase chain reaction and serological tests. A retrospective cohort study was conducted among 38 blood-sampled participants after the exclusion of 14 participants with evidence of past HEV infection. Relative risks (RR) and 95% confidence intervals were calculated based on food consumed at the wedding meal using univariate and multivariable Poisson regressions. Phylogenetic analyses were performed to compare the clinical HEV strains. Strains were detected in the liquid manure sampled at the farm where the piglet was born and in the untreated island wastewater. RESULTS: Seventeen cases were identified, 70.6% were asymptomatic. Acute HEV infection was independently associated with piglet stuffing consumption (RR = 1.69 [1.04-2.73], P = .03). Of clinical strains from the index cases, veterinary and environmental HEV strains were identical. CONCLUSIONS: Our investigation attributed this large HEV outbreak to the consumption of an undercooked pig liver-based stuffing. After infection, the cases became a temporary reservoir for HEV, which was detected in the island's untreated wastewater.

Community Incidence of Campylobacteriosis and Nontyphoidal Salmonellosis, France, 2008-2013.

Community incidence estimates are necessary to assess the burden and impact of infections on health and to set priorities for surveillance, research, prevention, and control strategies. The current study was performed to estimate the community incidence of campylobacteriosis and nontyphoidal salmonellosis in France from the number of laboratory-confirmed cases reported to the national reference center (NRC). The probabilities of a case in the community visiting a doctor, having a stool sample requested, having a positive laboratory test, and having the case reported to the NRC were estimated using data of national surveillance systems, national hospitalization and health insurance databases, and specific surveys informing about these parameters. Credible intervals (CrI) were calculated using Monte Carlo simulation. In addition, we estimated the number of hospitalizations for both infections in France. The annual community incidence rate in France is estimated at 842 cases per 100,000 (90%CrI 525-1690) for campylobacteriosis and 307 cases per 100,000 (90%CrI 173-611) for salmonellosis. The annual number of hospitalizations is estimated at 5182 for campylobacteriosis and 4305 for salmonellosis. The multiplication factors between cases ascertained by the surveillance system and cases in the community were 115 for campylobacteriosis and 20 for salmonellosis. They are consistent with estimates reported in other countries, indicating a high community incidence of campylobacteriosis and salmonellosis in France.

Acute diarrhea in adults consulting a general practitioner in France during winter: incidence, clinical characteristics, management and risk factors.

BACKGROUND: Data describing the epidemiology and management of viral acute diarrhea (AD) in adults are scant. The objective of this study was to identify the incidence, clinical characteristics, management and risk factors of winter viral AD in adults. METHODS: The incidence of AD in adults during two consecutive winters (from December 2010 to April 2011 and from December 2011 to April 2012) was estimated from the French Sentinelles network. During these two winters, a subset of Sentinelles general practitioners (GPs) identified and included adult patients who presented with AD and who filled out a questionnaire and returned a stool specimen for virological examination. All stool specimens were tested for astrovirus, group A rotavirus, human enteric adenovirus, and norovirus of genogroup I and genogroup II. Age- and sex-matched controls were included to permit a case-control analysis with the aim of identifying risk factors for viral AD. RESULTS: During the studied winters, the average incidence of AD in adults was estimated to be 3,158 per 100,000 French adults (95% CI [2,321 - 3,997]). The most reported clinical signs were abdominal pain (91.1%), watery diarrhea (88.5%), and nausea (83.3%). GPs prescribed a treatment in 95% of the patients with AD, and 80% of the working patients with AD could not go to work. Stool examinations were positive for at least one enteric virus in 65% (95% CI [57 - 73]) of patients with AD with a predominance of noroviruses (49%). Having been in contact with a person who has suffered from AD in the last 7 days, whether within or outside the household, and having a job (or being a student) were risk factors significantly associated with acquiring viral AD. CONCLUSIONS: During the winter, AD of viral origin is a frequent disease in adults, and noroviruses are most often the cause. No preventable risk factor was identified other than contact with a person with AD. Thus, at the present time, reinforcement of education related to hand hygiene remains the only way to reduce the burden of disease.

What is the incubation period for listeriosis?

BACKGROUND: Listeriosis is a foodborne infection with a low incidence but a high case fatality rate. Unlike common foodborne diseases, the incubation period can be long. The first incubation periods were documented during a large listeriosis outbreak published in 1987 by Linnan and al. in the New England Journal of Medicine (range: 3 days to 70 days). Data on the incubation period of listeriosis are scarce. Our study aim was to estimate precisely the incubation period of listeriosis using available data since 1987. METHODS: We estimated the incubation period of listeriosis using available published data and data from outbreak investigations carried out by the French National Institute for Public Health Surveillance. We selected cases with an incubation period calculated when a patient had a single exposure to a confirmed food source contaminated by Listeria monocytogenes. RESULTS: We identified 37 cases of invasive listeriosis (10 cases with central nervous system involvement (CNS cases), 15 bacteraemia cases and 12 pregnancy-associated cases) and 9 outbreaks with gastroenteritis. The overall median incubation period of invasive listeriosis was 8 days (range: 1-67 days) and differed significantly by clinical form of the disease (p<0.0001). A longer incubation period was observed for pregnancy-associated cases (median: 27.5 days; range: 17-67 days) than for CNS cases (median: 9 days; range: 1-14 days) and for bacteraemia cases (median: 2 days; range: 1-12 days). For gastroenteritis cases, the median incubation period was 24 hours with variation from 6 to 240 hours. CONCLUSIONS: This information has implications for the investigation of food borne listeriosis outbreaks as the incubation period is used to determine the time period for which a food history is collected. We believe that, for listeriosis outbreaks, adapting the exposure window for documenting patients' food histories in accordance with the clinical form of infection will facilitate the identification of food products as the source of contamination. We therefore propose to take an exposure window of 14 days before the diagnosis for CNS and bacteraemia cases, and of 6 weeks before the diagnosis, for pregnancy-associated cases.

Burden of influenza, healthcare seeking behaviour and hygiene measures during the A(H1N1)2009 pandemic in France: a population based study.

BACKGROUND: Influenza surveillance systems do not allow the identification of the true burden of illness caused by influenza in the community because they are restricted to consulting cases. A study was conducted to estimate the incidence and the burden of self-defined influenza, and to describe healthcare seeking behavior for self-defined influenza during the A(H1N1)2009 pandemic in the French population. METHODS: We conducted a random-based retrospective cross-sectional telephone survey between May 2009 and April 2010 among a random sample of the French population. RESULTS: For the 10 076 people included, 107 episodes of self-defined influenza were reported. The annual incidence of self-defined influenza was estimated at 13 942 cases per 100 000 inhabitants (CI95% 10 947 - 16 961), 62.1% (CI95% 50.5 - 72.5) of cases consulted a physician and 11.3% (CI95% 5.5 - 21.7) used a face mask. Following recommendations, 37.5% (CI95% 35.5 - 39.5) of people in the survey reported washing their hands more often during the pandemic season, and there was a positive association with being vaccinated against A(H1N1)2009 influenza, being a women, being a child (< 15 years) or living in a big city (≥ 100 000 inhabitants). CONCLUSIONS: Self-defined influenza causes a significant burden of illness in the French population and is a frequent cause for consultation. These results allow a more accurate interpretation of influenza surveillance data and an opportunity to adapt future health education messages.

Simultaneous investigation of influenza and enteric viruses in the stools of adult patients consulting in general practice for acute diarrhea.

BACKGROUND: Gastrointestinal symptoms are not an uncommon manifestation of an influenza virus infection. In the present study, we aimed to investigate the presence of influenza viruses in the stools of adult patients consulting their general practitioner for uncomplicated acute diarrhea (AD) and the proportion of concurrent infections by enteric and influenza viruses. METHOD: A case-control study was conducted from December 2010 to April 2011. Stool specimens were collected and tested for influenza viruses A (seasonal A/H3N2 and pandemic A/H1N1) and B, and for four enteric viruses (astrovirus, group A rotavirus, human enteric adenovirus, norovirus of genogroups I - NoVGI - and genogroup II - NoVGII). RESULTS: General practitioners enrolled 138 cases and 93 controls. Of the 138 stool specimens collected, 92 (66.7%) were positive for at least one of the four enteric viruses analysed and 10 (7.2%) tested positive for one influenza virus. None of these 10 influenza positive patients reported respiratory symptoms. In five influenza-positive patients (3.6%), we also detected one enteric virus, with 4 of them being positive for influenza B (2 had co-detection with NoVGI, 1 with NoVGII, and 1 with astrovirus). None of the 93 controls tested positive for one of the enteric and/or other influenza viruses we investigated. CONCLUSIONS: In this study we showed that the simultaneous detection of influenza and enteric viruses is not a rare event. We have also reported, for the first time in general practice, the presence of seasonal and pandemic influenza viruses in the stools of adult patients consulting for uncomplicated AD. A simultaneous investigation of enteric and influenza viruses in patients complaining of gastrointestinal symptoms could be useful for future studies to better identify the agents responsible for AD.

Long-term outcome of patients presenting with acute infectious encephalitis of various causes in France.

BACKGROUND: A prospective study of infectious encephalitis was conducted in France in 2007. In total, 253 patients were enrolled with a proven etiological diagnosis for 52%. The cohort of surviving patients with encephalitis was assessed for sequelae and impairment 3 years after enrollment. METHODS: Patients, their family, and general practitioners (GPs) were interviewed by phone to document persisting symptoms, return to work, and past and current leisure activities, with standardized questionnaires. The IQCODE (Informant Questionnaire on Cognitive Decline in the Elderly) was completed with relatives. The global outcome was determined in all patients with the Glasgow outcome scale. RESULTS: In 2010, 20 patients (10%) were unavailable for follow-up, 2 (1%) were excluded, and 18 (9%) had died since hospital discharge. Data were available for 167 survivors and 9 patients whose death was related to the encephalitis. The outcome was favorable in 108 of 176 patients (61%) (71 with complete resolution), 31 (18%) were mildly impaired, 25 (14%) were severely impaired, and 3 (1%) were in a vegetative state. The most frequent symptoms were difficulty concentrating (42%), behavioral disorders (27%), speech disorders (20%), and memory loss (19%). Fifteen of 63 patients (24%) previously employed were still unable to resume work. Long-term outcome was significantly associated with comorbid conditions, age, level of education, and the causative agent of encephalitis. CONCLUSIONS: Most patients with encephalitis experienced a favorable outcome 3 years after hospital discharge. However, minor to severe disability persists in a high number of cases with consequences for everyday life. Physical and mental impairment should be evaluated in all patients with encephalitis, and neuropsychological rehabilitation implemented whenever needed.

Outbreak of Shiga toxin-producing Escherichia coli O104:H4 associated with organic fenugreek sprouts, France, June 2011.

BACKGROUND: On 22 June 2011, 8 patients with hemolytic uremic syndrome (HUS) or bloody diarrhea were reported in France. All 8 were attendees of a community center event on 8 June near Bordeaux. Three Escherichia coli cases were confirmed by isolation of Shiga toxin-producing E. coli O104:H4 stx2 aggR producing a cefotaximase (CTX-M) ß-lactamase (STEC O104:H4); the same rare serotype caused the outbreak in Germany in May-July 2011. An investigation was initiated to describe the outbreak, identify the vehicle for infection, and guide control measures. METHODS: We conducted a retrospective cohort study among all adults attending the event, including food handlers. A standardized questionnaire was administered to participants. A case was an attendee who developed HUS or diarrhea between 8 and 24 June. Cases were confirmed by isolation of STEC O104:H4 or O104 serology. Relative risks (RRs) and 95% confidence intervals (CIs) by exposure were calculated using a Poisson regression model. RESULTS: Twenty-four cases were identified (14% attack rate). Of these, 18 (75%) were women, 22 (92%) were adults, 7 (29%) developed HUS, 5 (21%) developed bloody diarrhea, and 12 (50%) developed diarrhea. Ten (42%) cases were confirmed. Fenugreek was the only sprout type with an independent association to illness (RR, 5.1; 95% CI, 2.3-11.1) in multivariable analysis. CONCLUSIONS: This investigation identified a point-source STEC O104:H4 outbreak associated with consumption of fenugreek sprouts. Comparison of results from French and German STEC O104:H4 outbreak investigations enabled identification of a common food vehicle, fenugreek sprouts, and resulted in implementation of Europe-wide control measures in July 2011.

Impaired quality of life after chikungunya virus infection: a 2-year follow-up study.

OBJECTIVES: To measure the frequency of and risk factors for rheumatic manifestations after chikungunya virus (CHIKV) infection and to assess their impact on quality of life (QoL). METHODS: In a cohort study among 509 cases diagnosed in France, demographic and clinical characteristics were collected at baseline, and QoL status by 36-item short-form health survey (SF-36), a short form of the Arthritis Impact Measurement Scales 2 (AIMS2-SF) and General Health Questionnaire (GHQ-12) at follow-up. SF-36 scores were compared with population norms. Factors associated with QoL were identified in multivariate linear regression models. RESULTS: A total of 391 (77%) patients participated (53.5% female, mean age 50.2 years). Median time from onset at follow-up was 23.4 months. Among 176 recovered patients, a shorter duration of symptoms was observed in younger age groups and male patients. The probability of full recovery at 1 year was 0.39. Those not recovered were older, had more comorbidities and a longer acute stage with joint swelling. Scores of physical and mental components of the SF-36 and GHQ-12 were low. The AIMS2-SF was affected mainly in symptoms, psychological and social dimensions. Recovered patients did not differ significantly from age- and gender-matched population SF-36 norms. Older age (P = 0.01-0.002) was associated with lower SF-36 scores. Other factors associated with lower SF-36, lower GHQ12 scores and higher AIMS2-SF dimensions were lack of recovery (P = 0.017 to <0.0001), presence of comorbidity (P = 0.005 to <0.0001) and a longer duration of acute stage (P = 0.047 to <0.0001). CONCLUSION: Medical follow-up with special attention to comorbidity providing information on possible chronic symptoms and giving support for potential depression and anxiety are recommended.

[Foodborne infections in France]. / Les infections d'origine alimentaire en France.

Prevention and control measures implemented along the human food chain in recent decades have been largely successful, as shown by the dramatic decrease in the incidence of listeriosis and certain Salmonella serotypes. However, foodborne illness continues to be a serious public health threat, due mainly to Salmonella, Listeria monocytogenes and Campylobacter. Infections caused by less frequent micro-organisms such as shigatoxin-producing E. coli are also a concern, because of their serious health consequences and epidemic potential. Surveillance of foodborne illness has revealed several important trends, including a substantial recent increase in infections by monophasic variants of Salmonella typhimurium, a continuing increase in the incidence of Campylobacter infections, and a rapid increase in the frequency and antibiotic resistance of Salmonella and Campylobacter isolates. These developments highlight the importance of epidemiological and microbiological surveillance of humain foodborne infections; as well as the need for very close collaboration among all those responsible for the surveillance of animal health and the human foodchain.

Incidence of listeriosis and related mortality among groups at risk of acquiring listeriosis.

BACKGROUND: Listeriosis is a foodborne disease of significant public health concern that primarily affects persons with recognized underlying conditions or diseases that impair cell-mediated immunity. The degree of risk posed by the different underlying conditions is crucial to prioritize prevention programs that target the highest risk populations. METHODS: We reviewed cases of listeriosis reported in France from 2001 to 2008. Numbers of cases and deaths were tabulated by age and underlying condition. Measures of the impact of specific underlying conditions on the occurrence of listeriosis were calculated. For estimating the total number of persons living with specific diseases, we applied prevalence estimates of these diseases to the French population. Underlying conditions were ranked by the degree to which they increased the risk of listeriosis. RESULTS: From 2001 to 2008, 1959 cases of listeriosis were reported in France (mean annual incidence 0.39 per 100,000 residents). Compared with persons <65 years with no underlying conditions, those with chronic lymphocytic leukemia had a >1000-fold increased risk of acquiring listeriosis, and those with liver cancer; myeoloproliferative disorder; multiple myeloma; acute leukemia; giant cell arteritis; dialysis; esophageal, stomach, pancreas, lung, and brain cancer; cirrhosis; organ transplantation; and pregnancy had a 100-1000-fold increased risk of listeriosis. CONCLUSIONS: To be effective and acceptable to physicians and patients, listeriosis prevention strategies should be targeted based on evidence of increased risk. Stringent dietary guidance, to avoid specific foods with a high risk for Listeria contamination, should be targeted to pregnant women and to others at highest risk of listeriosis.

Preclinical sporadic Creutzfeldt-Jakob disease in French blood donors: an epidemiologic model-based study.

BACKGROUND: A recent case-control study showed that transfusion recipients were at an increased risk of developing sporadic Creutzfeldt-Jakob disease (sCJD), suggesting that blood donors with silent preclinical sCJD could transmit the sCJD agent. We therefore estimated the annual number of French blood donors expected to have preclinical sCJD at the time of donation. STUDY DESIGN AND METHODS: We developed a mathematical model to estimate the number of blood donors who would subsequently develop sCJD, under various assumptions about how long their blood might be infective before clinical onset. The model used distributions by age group and sex for sCJD cases, blood donor population, French general population, and mortality in the general population. RESULTS: Using 1999 to 2008 data, modeling showed that, each year, a mean of 1.1 (standard deviation [SD], 0.3) donors were within 1 year of sCJD onset at the time of blood donation, 6.9 (SD, 0.5) donors were within 5 years, 18.0 (SD, 0.6) were within 10 years, and 33.4 (SD, 1.1) were within 15 years. CONCLUSION: Few donors are expected to be in the late preclinical stage of sCJD at the time of blood donation. This result and that of the worldwide absence of any epidemic increase in sCJD over the years indicate that this risk of transfusion-transmitted sCJD, if any, is likely to be very low.

Can mortality data provide reliable indicators for Creutzfeldt-Jakob disease surveillance? A study in France from 2000 to 2008.

BACKGROUND: Surveillance of Creutzfeldt-Jakob disease (CJD) is still an important issue because of the variant CJD epidemic, which is in decline and also because of the emergence of novel forms of animal transmissible spongiform encephalopathy with zoonotic potential and the risk of nosocomial and blood transfusion-related transmission. Active surveillance has been implemented in most European countries and requires important human resources and funding. Here, we studied whether national mortality and morbidity statistics can be used as reliable indicators. METHODS: CJD data collected by the French national CJD surveillance centre were compared with data registered in the national mortality statistics. RESULTS: From 2000 to 2008, the two sources reported fairly similar numbers of CJD deaths. However, analysis of individual data showed important between-sources disagreement. Nearly 24% of CJD reported by the mortality register were false-positive diagnoses and 21.6% of the CJD cases diagnosed by the surveillance centre were not registered as CJD in the national mortality statistics. One out of 22 variant CJD cases was not reported as having any type of CJD in the mortality statistics. CONCLUSIONS: These findings raise doubt about the possibility of a reliable CJD surveillance only based on mortality data.

Influenza vaccination coverage against seasonal and pandemic influenza and their determinants in France: a cross-sectional survey.

BACKGROUND: Following the emergence of the influenza A(H1N1)2009 virus, the French ministry of health decided to offer free vaccination against pandemic influenza to the entire French population. Groups of people were defined and prioritised for vaccination. METHODS: We took a random sample of the population of mainland France and conducted a retrospective cross-sectional telephone survey to estimate vaccination coverage against seasonal and pandemic influenza and to identify determinants of these vaccinations. RESULTS: 10,091 people were included in the survey. Overall seasonal influenza vaccination coverage (IVC) remained stable in the population from the 2008-2009 season to the 2009-2010 season reaching 20.6% and 20.8% respectively. Overall pandemic IVC in the French population is estimated to be 11.1% (CI95%: 9.8 - 12.4). The highest pandemic IVC was observed in the 0-4 years age group. For individuals with health conditions associated with higher risk of influenza, pandemic IVC was estimated to be 12.2% (CI95%: 9.8 - 15.1). The main determinants associated with pandemic influenza vaccine uptake were: living in a household with a child < 5 years ORadj: 2.0 (CI95%: 1.3 - 3.1) or with two children < 5 years or more, ORadj: 2.7 (CI95%: 1.4 - 5.1), living in a household where the head of the family is university graduate (>2 years), ORadj: 2.5 (CI95%: 1.5 - 4.1), or has a higher professional and managerial occupation, ORadj: 3.0 (CI95%: 1.5 - 5.5) and being vaccinated against seasonal influenza, ORadj: 7.1 (CI95%: 5.1 - 10.0). Being an individual with higher risk for influenza was not a determinant for pandemic influenza vaccine uptake. These determinants are not the same as those for seasonal influenza vaccination. CONCLUSIONS: Overall A(H1N1)2009 influenza vaccine uptake remained low, particularly among individuals with higher risk for influenza and was lower than that observed for seasonal influenza. The reasons behind people's reluctance to be vaccinated need to be investigated further.

Undercooked ground beef and person-to-person transmission as major risk factors for sporadic hemolytic uremic syndrome related to Shiga-toxin producing Escherchia coli infections in children in France.

In a prospective matched case-control study of sporadic pediatric hemolytic uremic syndrome related to Shiga-toxin producing Escherichia coli infection in France, eating undercooked ground beef, contact with a person with diarrhea, and drinking well water during the summer period were identified as risk factors. Prevention efforts in France should focus on reducing not only food-borne but also person-to-person transmission.

Outbreak of Salmonella enterica serotype Montevideo infections in France linked to consumption of cheese made from raw milk.

In 2006, an outbreak of Salmonella enterica serotype Montevideo infections occurred in France. A matched case-control study and microbiological, environmental, and veterinary investigations were conducted to determine the source of this outbreak. A case was defined as a resident of France in whom Salmonella Montevideo was isolated from a stool or blood specimen between October 16, 2006, and January 6, 2007. Patients were interviewed using a standardized questionnaire. Salmonella Montevideo food isolates collected in 2006 by the nonhuman Salmonella surveillance system were reviewed, and a trace-back investigation was carried out. Salmonella strains isolated in case-patients and in suspected food were subtyped by pulsed-field gel electrophoresis (PFGE). Twenty-three cases were identified. Ten (63%) of the 16 interviewed cases against only 11 (35%) of the 31 controls reported eating a soft cheese made with raw milk from cows. Contaminated cheese was traced to a single processing plant that had faced an episode of Salmonella Montevideo contamination in September-October 2006. At that time, the distribution of batches of cheese found contaminated by Salmonella Montevideo was blocked. Microbiological investigation indicated that 70% (16/23) of strains isolated from case-patients and 93% (28/30) of strains isolated from cheese produced by the incriminated plant shared indistinguishable PFGE patterns. Comparing the onset of illness of cases and cheese production time in the incriminated plant, we concluded that this Salmonella outbreak was caused by raw-milk cheese in which low-level contamination had gone undetected.

Surveillance of hemolytic uremic syndrome in children less than 15 years of age, a system to monitor O157 and non-O157 Shiga toxin-producing Escherichia coli infections in France, 1996-2006.

BACKGROUND: Since the 1980s, Shiga toxin-producing Escherichia coli (STEC), especially E. coli O157:H7, has been an important cause of food borne disease in industrial countries. In France, as there was no routine screening for STEC in clinical laboratories, enhanced surveillance of hemolytic uremic syndrome (HUS) in children less than 15 years of age was established in 1996 to monitor trends in the incidence of STEC infections. METHODS: The surveillance system was based on a voluntary national network of pediatricians of 31 pediatric nephrology units in public hospitals. RESULTS: From 1996 to 2006, the mean annual incidence of HUS was 0.71 cases per 100,000 children less than 15 years of age and 1.87 cases per 100,000 children less than 5 years of age. STEC infections were confirmed in 66% of patients; STEC O157 was the most common serogroup identified in STEC-related HUS (83%). In this 11-year period, 96% of HUS cases were sporadic and only 2 outbreaks caused by STEC O157 and by a dual infection of STEC O26 and O80 were detected. CONCLUSIONS: An evaluation of the surveillance of pediatric HUS showed that it is a simple and useful system for monitoring trends in STEC infections in France. It provides the information needed to measure the impact of new and changing vehicles of STEC transmission, and evaluate the effectiveness of prevention measures.