V Goulet

Increasing incidence of listeriosis in France and other European countries

The cause of an increase among persons >60 years of age in France is unknown.

Listeriosis Outbreak Associated with the Consumption of Rillettes in France in 1993

An outbreak of listeriosis involving 38 patients occurred in France between 18 June and 5 October 1993. The epidemic clone was characterized by serovar 4b, phagovar 2671:108:312, and DNA macrorestriction patterns 12 and 13. Thirty-one case-patients were materno-neonatal patients and 7 patients were nonpregnant adults. Preliminary analysis of a case-control study implicated a pork product, rillettes, of a particular brand (odds ratio, 18; 95% confidence interval, 2.2-208) as the vehicle of infection. Rillettes is a ready-to-eat food prepared with ham meat cooked with grease. The implicated lots of rillettes were recalled in mid-August, and the French authorities issued a warning to the general public. Microbiologic analysis of unopened plastic cans of rillettes confirmed the results of the case-control study 3 weeks after the recall. Final analysis showed that the rillettes was the major vehicle of the outbreak but suggested that other brand A meat products could also have been involved.

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.

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) β-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.

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.

What is the incubation period for listeriosis

BackgroundListeriosis 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.MethodsWe 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.ResultsWe 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.ConclusionsThis 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.

Toxoplasmosis among pregnant women in France: risk factors and change of prevalence between 1995 and 2003.

BACKGROUND Congenital toxoplasmosis may affect any organ, produce severe complications such as hydrocephalus and lead to ocular lesions which can appear late after birth. Fetal outcome can be fatal. During pregnancy, the mother can become infected, particularly by eating undercooked meat or poorly washed raw fruits and vegetables. In France, prevention of congenital toxoplasmosis is based on serial serology tests, performed repeatedly until delivery for pregnant women who remain negative then at the first prenatal visit. METHODS We used toxoplasmosis serology data collected during national perinatal surveys conducted in 1995 and 2003 to estimate toxoplasmosis prevalence, assess risk factors and ascertain time trends in prevalence. In each survey, socioeconomic variables as well as the serological status for toxoplasmosis were collected for all pregnant women who had terminated a pregnancy during a given week period. RESULTS In 2003, 15,108 pregnant women were included; the prevalence of Toxoplasma infection was 43.8% (95% CI: 43.0-44.6). Prevalence increased with age and was greater for those who lived in the Southwest of France, the greater Paris area and in overseas districts. In 2003, as in 1995, prevalence increased with education level, occupational status of the household and number of pregnancies. Prevalence decreased 19% between 1995 and 2003. The decrease was significantly greater for pregnant women aged less than 30 years than for those aged more or equal to 30 years. CONCLUSION Although it decreased over time, toxoplasmosis prevalence remained higher in France than in other European countries. With more than one out of two women in France susceptible of having Toxoplasma infection, it is important to promote preventive measures to avoid infection during pregnancy.

Incidence and prevalence of Toxoplasma gondii infection in women in France, 1980-2020: model-based estimation.

Toxoplasmosis is a worldwide zoonosis due to Toxoplasma gondii, a ubiquitous protozoan parasite of warm-blooded animals including humans. In pregnant women, primary infection can cause congenital toxoplasmosis resulting in severe malformations in the newborn. Since 1978, public health authorities in France have implemented a congenital toxoplasmosis prevention programme, including monthly serological screening of all seronegative pregnant women, and treatment in case of seroconversion. However, this programme does not produce systematic surveillance data on incidence and prevalence. Our objective was to estimate the incidence and prevalence of T. gondii infection, and the incidence of seroconversion during pregnancy in women in France. We used a catalytic model to estimate incidence and prevalence of Toxoplasma infection between 1980 and 2020 in women of childbearing age. We used age- and time-specific seroprevalence data obtained from the National Perinatal Surveys (NPS) conducted in 1995, 2003 and 2010. We assumed that incidence depends both on age and calendar time, and can be expressed as the product of two unknown functions. We also estimated incidence of seroconversion during pregnancy in 2010 from the NPS and the National Surveillance of Congenital Toxoplasmosis (ToxoSurv). We combined data of 42208 women aged 15-45 years with serology available from the three NPS. For women aged 30 years the modelled incidence decreased from 7·5/1000 susceptible women in 1980 to 3·5/1000 in 2000. In 2010 the incidence was 2·4/1000. The predicted incidence and prevalence for 2020 was 1·6/1000 and 27%, respectively. The incidence of seroconversion during pregnancy in 2010 was estimated at 2·1/1000 susceptible pregnant women (95% CI 1·3-3·1) from the NPS and 1·9 (95% CI 1·8-2·1) from ToxoSurv. Incidence and prevalence of Toxoplasma infection has decreased markedly during the last 30 years. This decrease may be explained by a lower exposure to the parasite by changes in food habits and by improved hygiene practices in meat production. Modelled estimations were consistent with estimates observed in other studies conducted previously in France. The catalytic modelling provides reliable estimates of incidence and prevalence of Toxoplasma infection over time. This approach might be useful for evaluating preventive programme for toxoplasmosis.

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, France.

To the Editor: Lymphogranuloma venereum (LGV), a sexually transmitted disease (STD) caused by Chlamydia trachomatis serovars L1, L2, or L3, is prevalent in tropical areas but occurs sporadically in the western world, where most cases are imported (1). LVG commonly causes inflammation and swelling of the inguinal lymph nodes, but it can also involve the rectum and cause acute proctitis, particularly among men who have sex with men. However, LGV serovars of C. trachomatis remain a rare cause of acute proctitis, which is most frequently caused by Neisseria gonorrhoeae or by non-LGV C. trachomatis (2). In 1981, in a group of 96 men who have sex with men with symptoms suggestive of proctitis in the United States, Quinn et al. found that 3 of 14 C. trachomatis infections were caused by LGV serovar L2 (3). In France, 2 cases of rectal LGV were reported in an STD clinic in Paris from 1981 to 1986 (4). In 2003, an outbreak of 15 rectal LGV cases was reported among men who have sex with men in Rotterdam; 13 were HIV-infected, and all reported unprotected sex in neighboring countries, including Belgium, France, and the United Kingdom (5). At the same time, a rise in C. trachomatis proctitis (diagnosed by using polymerase chain reaction [PCR]; [Cobas Amplicor Roche Diagnostic System, Meylan, France]) was detected in 3 laboratories in Paris and in the C. trachomatis national reference center located in Bordeaux. To identify the serovars of these C. trachomatis spp., all stored rectal specimens were analyzed by using a nested omp1 PCR-restriction fragment length polymorphism assay. The amplified DNA product was digested by restriction enzymes. Analysis of digested DNA was performed by electrophoresis. Patterns were compared visually with reference patterns (6). From January 1, 2003, to March 31, 2004, a total of 44 of 124 male rectal swabs were positive for C. trachomatis. Of those, 38 were identified as belonging to the L2 serotype, which confirms the diagnosis of rectal LGV. Epidemiologic information was retrospectively obtained by clinicians through review of medical records, telephone interview, or both. A complete history was available for 14 of the 38 cases. All 14 men reported unprotected anal sex with anonymous male sex partners in France, and none reported a stay in an LGV-endemic area. Their mean age was 40 years (31–50); 8 were HIV-infected, and 9 had another concomitant STD. The mean duration of symptoms before LGV diagnosis was 50 days (range 11–120 days). All 14 patients had symptoms of acute proctitis, including rectal pain, discharge, and tenesmus, and 3 (all HIV-infected) had fever. Deep, extended rectal ulcerations were reported in 8 patients, 3 of whom were HIV-infected and had lesions suggestive of rectal carcinoma. In 1 patient in whom a late diagnosis was made 4 months after the onset of symptoms, a rectal tumorlike stricture was observed. All 14 patients were treated with tetracycline for a mean duration of 16 days (range 10–60 days). An information campaign among microbiologists and clinicians and a sentinel LGV surveillance system were launched in April 2004. Subsequently, LGV was diagnosed in 65 additional male patients, some retrospectively. In total, rectal LGV was diagnosed in 103 patients from July 2002 to August 2004 (Figure). Figure Number of rectal lymphogranuloma venereum cases diagnosed in men in France, July 2002–August 2004. Prompt diagnosis and treatment is indeed paramount to prevention and control. Diagnosis may be further hampered because rectal LGV may mimic other conditions such as rectal carcinoma or Crohn disease. Treatment duration should be no shorter than 21 days, and follow-up examinations should be conducted until all signs and symptoms have resolved (7,8). If left untreated, rectal LGV could lead to serious complications such as rectal stricture (1). If recently exposed to infection, sexual contacts should receive prophylactic treatment to prevent reinfection and to eliminate a potential reservoir. The emergence of rectal LGV, characterized by deep mucosal ulcerations and frequently occurring in HIV-infected men who have sex with men, is a serious concern for the gay community in Europe.