Crimean-Congo Hemorrhagic Fever Virus in Ticks Collected from Cattle, Corsica, France, 2023.

We report the detection of Crimean-Congo hemorrhagic fever virus (CCHFV) in Corsica, France. We identified CCHFV African genotype I in ticks collected from cattle at 2 different sites in southeastern and central-western Corsica, indicating an established CCHFV circulation. Healthcare professionals and at-risk groups should be alerted to CCHFV circulation in Corsica.

What is the relevancy of a surveillance of mumps without a systematic laboratory confirmation in highly immunized populations? Epidemiology of suspected and biologically confirmed mumps cases seen in general practice in France between 2014 and 2020.

BACKGROUND: In France, mumps surveillance is conducted in primary care by the Sentinelles network, the National Reference Centre for Measles, Mumps and Rubella and Santé publique France. AIM: The objective of this study was to estimate the incidence of suspected mumps in general practice, the proportion of laboratory confirmed cases and the factors associated with a virological confirmation. METHODS: General practitioners (GPs) participating in the Sentinelles network should report all patients with suspected mumps according to a clinical definition in case of parotitis and a serological definition in case of clinical expression without parotitis. All suspected mumps cases reported between January 2014 and December 2020 were included. A sample of these cases were tested by real time reverse transcriptase polymerase chain reaction (RT-PCR) for mumps biological confirmation. RESULTS: A total of 252 individuals with suspected mumps were included in the study. The average annual incidence rate of suspected mumps in general practice in France between 2014 and 2020 was estimated at 11 cases per 100,000 population [CI95%: 6-17]. A mumps confirmation RT-PCR test was performed on 146 cases amongst which 17 (11.5 %) were positive. Age (between 20 and 29 years old), the presence of a clinical complication and an exposure to a suspected mumps case within the 21 days prior the current episode were associated with a mumps biological confirmation. CONCLUSION: If these results confirm the circulation of mumps virus in France, they highlight the limits of a surveillance without a systematic laboratory confirmation in highly immunized populations.

Seroprevalence of anti-HEV IgG in children: very early exposure in young children in a hyperendemic region.

Background and objectives: Hepatitis E virus (HEV) can be considered an emerging zoonotic pathogen and is an important cause of acute viral hepatitis in high-income countries. Corsica has been identified as a hyperendemic region for HEV. We aimed to characterize the prevalence of IgG among children and estimate the annual force of infection of HEV. Methods: From April 2020 to June 2021, we collected 856 "residual sera" in 13 medical biology laboratories. Sera were tested using the Wantaï HEV IgG assay. Data were weighted according to the distribution by sex and age of the real Corsican population. Serocatalytic models were applied to assess the annual force of infection of HEV. Results: The weighted seroprevalence was 30.33% [27.15-34.0]. The seroprevalence was only associated with increasing age (7.25-40.52%; p < 0.001). The annual probability of infection was 5.4% for adults and children above 10-year-old and 2.2% for children under 10 yo. Conclusion: Our study demonstrates that in the hyperendemic island of Corsica, (i) exposure of the population to HEV is homogeneous at the spatial level with no difference between genders; (ii) HEV exposure occurs from birth, resulting in 7.4% seropositivity at the age of 4 years; and (iii) super exposure is observed after the age of 9 years. Accordingly, specific studies should be conducted to determine the breadth of the situation identified in our study. The role of the environment and its contamination by domestic or wild swine excreta should be investigated using a One Health approach.

Eight Months of Serological Follow-Up of Anti-SARS-CoV-2 Antibodies in France: A Study among an Adult Population.

BACKGROUND: Uncertainties remain regarding the nature and durability of the humoral immune response to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). AIM: This study investigated immunoglobulin G response and neutralizing activity to evaluate the mean antibody concentrations and response duration induced by each vaccination regimen in a French adult population. METHODS: A study including blood sampling and questionnaires was carried out from November 2020 to July 2021 with three separate follow-up phases. Spike proteins and neutralizing antibodies were quantified using ELISA and a virus-neutralization test. RESULTS: Overall, 295 participants were included. Seroprevalences were 11.5% (n = 34), 10.5% (n = 31), and 68.1% (n = 201) in phases 1, 2, and 3, respectively. Importantly, 5.8% (n = 17) of participants lost their natural antibodies. Antibody response of participants with only a prior infection was 88.2 BAU/mL, significantly lower than those vaccinated, which was 1909.3 BAU/mL (p = 0.04). Moreover, the antibody response of vaccinated participants with a prior infection was higher (3593.8 BAU/mL) than those vaccinated without prior infection (3402.9 BAU/mL) (p = 0.78). Vaccinated participants with or without prior infection had a higher seroneutralization rate (91.0%) than those unvaccinated with prior infection (65.0%). CONCLUSION: These results demonstrated that single infection does not confer effective protection against SARS-CoV-2.

Is the Alpha Variant of SARS-CoV-2 Associated with a Higher Viral Load than the Historical Strain in Saliva Samples in Patients with Mild to Moderate Symptoms?

During the COVID-19 pandemic, several generic variants emerged, including the Alpha variant, with increased transmissibility compared to historical strains. We aimed to compare the evolution of the viral load between patients infected with the Alpha variant and those infected with the historical SARS-CoV-2 strains, while taking into account the time interval between the onset of symptoms and samples. We used data collected from patients with an acute respiratory infection (mild to moderate symptoms) and seen in consultation in primary care, included in a prospective longitudinal study, COVID-A. Patients performed four salivary samples during the follow-up. All patients who had at least one of the saliva samples test positive for SARS-CoV-2 were included in the analysis. Overall, 118 patients were included: 89 infected by the historical strain and 29 infected by the Alpha variant. Even though we tended to observe a higher viral load in the Alpha variant group, we found no significant difference in the evolution of the viral load in saliva samples between patients infected with the Alpha variant of the SARS-CoV-2 and those infected by historical strains when controlling for the time interval between the onset of symptoms and sampling.

A Cross-Sectional Study of Exposure Factors Associated with Seropositivity for SARS-CoV-2 Antibodies during the Second Epidemic Wave among a Sample of the University of Corsica (France).

This study aimed to estimate the seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection within the staff and student populations of the University of Corsica (France) during the second wave of the epidemic. METHODS: A cross-sectional survey was conducted from 23 November 2020 to 31 January 2021. The participants underwent blood sampling using a fingerstick procedure and completed an anonymized questionnaire. Sera were tested for the presence of anti-SARS-CoV-2 IgG (ELISA-S) and, if positive, with an in-house virus neutralization test (VNT). RESULTS: A total of 418 persons were included in the study. The overall seroprevalence was 12.8% (95% confidence interval (CI), 9.8-16.6%). A total of 15 (31%) of the 49 individuals who had a positive ELISA-S also had a positive VNT. Seropositivity was associated with living at the city campus during the week and on weekends (OR = 3.74 [1.40-12.00]), using public transportation/carpooling (OR = 2.00 [1.01-4.02]), and being in contact with a person who tested positive for SARS-CoV-2 (OR = 2.32 [1.20-4.40]). The main symptoms associated with seropositivity were "having had an acute respiratory infection" (OR = 3.05 [1.43-6.43]) and "experiencing loss of smell" (OR = 16.4 [5.87-50.7]). CONCLUSION: These results could be useful for SARS-CoV-2 prevention and control on university campuses.

Detection of porcine enteric viruses (Kobuvirus, Mamastrovirus and Sapelovirus) in domestic pigs in Corsica, France.

Many enteric viruses are found in pig farms around the world and can cause death of animals or important production losses for breeders. Among the wide spectrum of enteric viral species, porcine Sapelovirus (PSV), porcine Kobuvirus (PKoV) and porcine Astrovirus (PAstV) are frequently found in pig feces. In this study we investigated sixteen pig farms in Corsica, France, to evaluate the circulation of three enteric viruses (PKoV, PAstV-1 and PSV). In addition to the three viruses studied by RT-qPCR (908 pig feces samples), 26 stool samples were tested using the Next Generation Sequencing method (NGS). Our results showed viral RNA detection rates (i) of 62.0% [58.7-65.1] (n = 563/908) for PSV, (ii) of 44.8% [41.5-48.1] (n = 407/908) for PKoV and (iii) of 8.6% [6.8-10.6] (n = 78/908) for PAstV-1. Significant differences were observed for all three viruses according to age (P-value = 2.4e-13 for PAstV-1; 2.4e-12 for PKoV and 0.005 for PSV). The type of breeding was significantly associated with RNA detection only for PAstV-1 (P-value = 9.6e-6). Among the 26 samples tested with NGS method, consensus sequences corresponding to 10 different species of virus were detected. This study provides first insight on the presence of three common porcine enteric viruses in France. We also showed that they are frequently encountered in pigs born and bred in Corsica, which demonstrates endemic local circulation.

Endonuclease-based genotyping of the RBM as a method to track the emergence or evolution of SARS-CoV-2 variants.

Since the beginning of the COVID-19 pandemics, variants have emerged. Some of them display increased transmissibility and/or resistance to immune response. Most of the mutations involved in the functional adaptation are found in the receptor-binding motif (RBM), close to the interface with the receptor ACE2. We thus developed a fast molecular assay to detect mutations in the RBM coding sequence. After amplification, the amplicon is heat-denatured and hybridized with an amplicon of reference. The presence of a mutation can be detected using a mismatch-specific endonuclease and the cleavage pattern is analyzed by capillary electrophoresis. The method was validated on RNA of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants produced in vitro before being implemented for clinical samples. The assay showed 97.8% sensitivity and 97.8% specificity. The procedure can be set up for high-throughput identification of the presence of mutations and serve as a first-line screening to select the samples for full genome sequencing.

Impact of the Second Epidemic Wave of SARS-CoV-2: Increased Exposure of Young People.

We aimed to use serological surveillance based on serial cross-sectional sampling of residual sera obtained from clinical laboratories to compare the differences in age and sex profiles of infected persons in the first and second waves of SARS-CoV-2 in Corsica, France. Residual sera were obtained, including samples from individuals of all ages collected for routine screening or clinical management by clinical laboratories. All the sera collected were tested for the presence of anti-SARS-CoV-2 IgG using a kit for semi-quantitative detection of IgG antibodies against the S1 domain of the viral spike protein (ELISA-S). Samples that were borderline and positive in ELISA-S were tested with an in-house virus neutralization test. During the second-wave period, we collected between 6 November, 2020 and 12 February, 2021, 4,505 sera from patients aged 0-101 years (60.4% women). The overall weighted seroprevalence of residual sera collected during the second-wave period [8.04% (7.87-9.61)] was significantly higher than the overall weighted seroprevalence estimated at the end of the first wave between 16 April and 15 June, 2020 [5.46% (4.37-7.00)] (p-value = 0.00025). Ninety-eight (30.1%) of the 326 samples tested in the VNT assay had a positive neutralization antibody titer. Estimated seroprevalence increased significantly for men [odds ratio (OR) OR = 1.80 (1.30-2.54); p-value = 0.00026] and for people under 30 years of age [OR = 2.17 (1.46-3.28); p-value = 0.000032]. This increase was observed in young adults aged 20-29 years among whom antibody frequencies were around four-fold higher than those observed at the end of the first wave. In conclusion, our seroprevalence estimates, including the proportion of the participants who had produced neutralizing antibodies, indicate that in February, 2021 the population of Corsica was still far from being protected against SARS-Cov-2 by "herd immunity."

Are Posterior Oropharyngeal Saliva Specimens an Acceptable Alternative to Nasopharyngeal Sampling for the Monitoring of SARS-CoV-2 in Primary-Care Settings?

BACKGROUND: The present study was set up to evaluate the efficacy of virological surveillance using posterior oropharyngeal saliva samples to monitor the COVID-19 pandemic in general practice. METHODS: Posterior oropharyngeal saliva samples were collected without restriction on timing or alimentation by general practitioners from patients with acute respiratory infection (ARI) seen in consultation. Saliva samples were tested by real-time reverse transcription polymerase chain reaction for SARS-CoV-2 and 21 other respiratory pathogens. Results for SARS-CoV-2 in saliva samples were compared to results obtained using a nasopharyngeal swab (NPS) collected in a certified medical laboratory before or after the ARI consultation. RESULTS: Overall, 143 ARI patients were enrolled between 6 June 2020, and 19 January 2021. SARS-CoV-2 RNA was detected in 37.0% (n = 53) of saliva samples and in 39.0% (n = 56) of NPS. Both saliva and NPS were positive in 51 patients. Positive and negative results were concordant between saliva samples and NPS in 51 (96.2%) and in 85 (94.4%) patients, respectively, with a Cohen's Kappa coefficient of 0.89 (95% CI 0.82-0.97, p < 0.001). Other respiratory viruses were detected in 28.0% (n = 40) of the 143 saliva samples. CONCLUSIONS: Findings suggest that saliva samples could represent an attractive alternative to NPS for surveillance of SARS-CoV-2 in patients consulting for an ARI in primary care.

Estimation of influenza-attributable burden in primary care from season 2014/2015 to 2018/2019, France.

Influenza viruses cause seasonal epidemics whose intensity varies according to the circulating virus type and subtype. We aim to estimate influenza-like illness (ILI) incidence attributable to influenza viruses in France from October 2014 to May 2019. Physicians participating in the French Sentinelles network reported the number of patients with ILI seen in consultation and performed nasopharyngeal swabs in a sample of these patients. The swabs were tested by RT-PCR for the presence of influenza viruses. These clinical and virological data were combined to estimate ILI incidence attributable to influenza viruses by subtypes and age groups. Influenza incidence rates over seasons ranged from 1.9 (95% CI, 1.9; 2.0) to 3.4% (95% CI, 3.2; 3.6) of the population. Each season, more than half of ILI cases were attributable to influenza. Children under 15 years were the most affected, with influenza incidence rates ranging from 3.0 (95% CI, 2.8;3.3) to 5.7% (95% CI, 5.3;6.1). Co-circulation of several (sub)types of influenza viruses was observed each year, except in 2016/2017 where A(H3N2) viruses accounted for 98.0% of the influenza cases. Weekly ILI incidences attributable to each influenza virus (sub)type were mostly synchronized with ILI incidence, except in 2014/2015 and 2017/2018, where incidence attributable to type B viruses peaked few weeks later. The burden of medically attended influenza among patients with ILI is significant in France, varying considerably across years and age groups. These results show the importance of influenza surveillance in primary care combining clinical and virological data.

Impact of the lockdown on the burden of COVID-19 in outpatient care in France, spring 2020.

BACKGROUND: To limit the spread of SARS-CoV-2 several countries implemented measures to reduce the number of contacts such as a national lockdown. We estimated the impact of the first lockdown on the burden of COVID-19 in the community in France. METHODS: Physicians participating in the French Sentinelles network reported the number of patients with an acute respiratory infection (ARI) seen in consultation and performed nasopharyngeal swabs in a sample of these patients (first patient of the week). The swabs were tested by RT-PCR for the presence of SARS-CoV-2. Clinical and virological data were combined to estimate ARI incidence attributable to SARS-CoV-2 from 17 March to 10 May 2020. RESULTS: The incidence of ARI attributable to COVID-19 decreased after the second week of the lockdown period from 142 (95%CI [101; 183]) to 41 (95%CI [21; 60]) per 100,000 population. A decrease was observed in all areas in metropolitan France. The youngest age groups (<15-years-old) were least affected with a cumulated incidence estimated to 14 per 100,000 population during the study period. CONCLUSIONS: The data collected in primary care suggests that the first lockdown implemented in France during spring 2020 significantly reduced the incidence of acute respiratory infections including COVID-19 in France and limited the geographic spread of SARS-CoV-2.

Seroprevalence of SARS-CoV-2 IgG Antibodies in Corsica (France), April and June 2020.

Our aim was to assess the seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection after the lockdown in a sample of the Corsican population. Between 16 April and 15 June 2020, 2312 residual sera were collected from patients with a blood analysis conducted in one of the participating laboratories. Residual sera obtained from persons of all ages were tested for the presence of anti-SARS-CoV-2 Immunoglobulin G (IgG) using the EUROIMMUN enzyme immunoassay kit for semiquantitative detection of IgG antibodies against the S1 domain of viral spike protein (ELISA-S). Borderline and positive samples in ELISA-S were also tested with an in-house virus neutralization test (VNT). Prevalence values were adjusted for sex and age. A total of 1973 residual sera samples were included in the study. The overall seroprevalence based on ELISA-S was 5.27% (95% confidence interval (CI), 4.33-6.35) and 5.46% (4.51-6.57) after adjustment. Sex was not associated with IgG detection. However, significant differences were observed between age groups (p-value = 1 E-5). The highest values were observed among 10-19, 30-39, and 40-49 year-old age groups, ranging around 8-10%. The prevalence of neutralizing antibody titers ≥40 was 3% (2.28-3.84). In conclusion, the present study showed a low seroprevalence for COVID-19 in Corsica, a finding that is in accordance with values reported for other French regions in which the impact of the pandemic was low.

Epidemiology and Clinical Symptoms Related to Seasonal Coronavirus Identified in Patients with Acute Respiratory Infections Consulting in Primary Care over Six Influenza Seasons (2014-2020) in France.

There is currently debate about human coronavirus (HCoV) seasonality and pathogenicity, as epidemiological data are scarce. Here, we provide epidemiological and clinical features of HCoV patients with acute respiratory infection (ARI) examined in primary care general practice. We also describe HCoV seasonality over six influenza surveillance seasons (week 40 to 15 of each season) from the period 2014/2015 to 2019/2020 in Corsica (France). A sample of patients of all ages presenting for consultation for influenza-like illness (ILI) or ARI was included by physicians of the French Sentinelles Network during this period. Nasopharyngeal samples were tested for the presence of 21 respiratory pathogens by real-time RT-PCR. Among the 1389 ILI/ARI patients, 105 were positive for at least one HCoV (7.5%). On an annual basis, HCoVs circulated from week 48 (November) to weeks 14-15 (May) and peaked in week 6 (February). Overall, among the HCoV-positive patients detected in this study, HCoV-OC43 was the most commonly detected virus, followed by HCoV-NL63, HCoV-HKU1, and HCoV-229E. The HCoV detection rates varied significantly with age (p = 0.00005), with the age group 0-14 years accounting for 28.6% (n = 30) of HCoV-positive patients. Fever and malaise were less frequent in HCoV patients than in influenza patients, while sore throat, dyspnoea, rhinorrhoea, and conjunctivitis were more associated with HCoV positivity. In conclusion, this study demonstrates that HCoV subtypes appear in ARI/ILI patients seen in general practice, with characteristic outbreak patterns primarily in winter. This study also identified symptoms associated with HCoVs in patients with ARI/ILI. Further studies with representative samples should be conducted to provide additional insights into the epidemiology and clinical features of HCoVs.

Seroprevalence Study of Anti-HEV IgG among Different Adult Populations in Corsica, France, 2019.

Hepatitis E virus (HEV) is a major cause of acute hepatitis worldwide. In France, hyperendemic areas including Corsica have an anti-HEV Immunoglobulin G (IgG) prevalence higher than 50%. The aim of this study was to determine the seroprevalence of anti-HEV IgG in three adult populations in Corsica and the risk factors associated with antibody detection. Between 2017 and 2019, a total of 930 individuals, including 467 blood donors, 393 students or university staff members and 70 patients from general practice, were tested for the presence of anti-HEV IgG using the Wantai HEV IgG enzyme immunoassay kit and filled a questionnaire. The association between seropositivity and potential risk factors was tested with univariate and multivariate analyses. Out of the 930 samples, 52.3% (486/930) were seropositive-54.4% (254/467) among blood donors, 47.6% (187/393) among university students and 64.3% (45/70) among patients of general practice. Three main risk factors were identified: (i) skinning and butchering (Adjusted Odds Ratio aOR = 2.76, 95% confidence interval [95% CI] [1.51-5.37]; p-value < 10-3), (ii) consumption of a local pork live raw sausage (fittonu) (aOR = 1.95 95% CI [1.45-2.64]; p-value = 10-5), and (iii) increasing age (p-value = 0.003). Seropositivity rates between the different populations were homogeneous after age stratification. This cross-sectional study indicates a high anti-HEV IgG seroprevalence in the Corsican adult population, not significantly different between women and men and increasing with age. This serosurvey also showed homogeneity regarding the exposure to HEV among three different types of populations. Finally, we confirmed the endemicity of Corsica with respect to HEV and identified a strong association between consumption of figatellu/fittonu and the practice of skinning and butchering with the detection of anti-HEV IgG.

Circulation of Toscana Virus in a Sample Population of Corsica, France.

Sandfly-borne phleboviruses pathogenic to humans, such as Toscana virus (TOSV) and Sandfly Fever Sicilian virus (SFSV), are endemic in the Mediterranean region. In France, several autochthonous cases of TOSV infection have been described, causing either meningitis or encephalitis. The aim of the present study was to investigate the seroprevalence of TOSV and SFSV antibodies in a healthy population from Corsica. In this cross-sectional study, participants were enrolled (i) from a medical staff at the University of Corsica and (ii) from general practitioners of the Corsican Sentinelles Network. The seroprevalence study was based on a virus microneutralization assay. A total of 240 sera were tested. Altogether, 54 sera (22.5%) were confirmed positive for TOSV antibodies, whereas none were positive for SFSV (0/240). The residential district of participants was significantly associated with TOSV seropositivity (p value = 0.005). The rate of the seropositivity against TOSV in our study suggests that the Corsican population is well exposed to the TOSV. These results encourage the implementation of a systematic surveillance system including entomological, microbiological, and medical aspects for the collection of better information on the diseases that are associated with phleboviruses in Corsica and beyond in the regions where these viruses are present.

Drastic decline of hepatitis E virus detection in domestic pigs after the age of 6 months, Corsica, France.

Suidae is an important reservoir of hepatitis E virus (HEV) and a source of transmission to humans (direct contact or via consumption of meat products). Our goal was to characterize the epidemiology of HEV infecting domestic pigs in Corsica Island, a French region hyperendemic for HEV. In Corsica, traditional extensive (or semi-extensive) outdoor pig farming system is common. Sixteen farms were selected according to location and breeding system. Individual pig faeces samples were collected and qRT-PCR for detecting HEV RNA was performed. Nucleic acids from HEV-positive samples were amplified using specific ORF2 genotyping system. The genotype and subtype of the Corsican HEV sequences were determined by phylogenetic analysis. Among the 919 porcine faeces samples tested 9.2% (n = 85) were positive. The presence of viral RNA was correlated with (a) age (>6 months) Adjusted Odd Ratio (AOR) 0.25 [0.068-0.90] p = .032; 3-4 months AOR = 4.94 [2.30-10.62] p = .000043) with the logistic regression model with a random effect at the farm level. Among the 85 positive samples, 83 belonged to genotype 3c and two to genotype 3f. The highest prevalence was observed in the 3-4 months age group and older age (>6 months) was negatively related to HEV infection and this suggests that traditional breeding with a late slaughter age may limit the risk of transmission to humans. A kinetic study of pigs from birth to slaughtering would allow to ensure that the type of traditional breeding reported here is very favourable to the absence of the virus in slaughtered pigs and in pork products.

First detection of Ehrlichia minasensis in Hyalomma marginatum ticks collected from cattle in Corsica, France.

Ehrlichiosis are severe, feverish tick-borne illnesses caused by specific species within the genus Ehrlichia (Anaplasmataceae family). Recent data suggest that ruminants in Corsica area reservoir for several Anaplasmataceae species. The purpose of our study was to determine whether Ehrlichia species could be detected in ticks collected in Corsican ruminants by using molecular methods. Ticks were collected in northern Corsica: (i) in May 2016 from sheep bred in one farm located in a 5000-inhabitants village and (ii) from cattle in June and July 2016 in a slaughterhouse. There sheep and cattle whole skin was inspected and ticks were collected manually. A total of 647 ticks was collected in northern Corsica during this study: 556 (86%) belonged to the Rhipicephalus bursa species and 91 (14%) to Hyalomma marginatum. The 91 H. marginatum ticks were organized in 27 pools, of which one (3.7%) was found positive for the presence of E. minasensis; this pool consisted of six ticks collected from a cow bred and raised northwestern Corsica. Ehrlichial DNA was not detected in R. bursa ticks. The 16S rRNA and groEL gene sequences of Ehrlichia detected in the H. marginatum pool showed 100% (303/303 bp) and 99.8% (555/556) of nucleotide identity with E. minasensis, respectively. Phylogenetic analyses demonstrated the highest closeness with E. minasensis UFMG-EV genotype than to any other E. canis strains. To our knowledge, this is the first report of E. minasensis outside of Brazil, Ethiopia and Canada. This identification of E. minasensis in H. marginatum merits to be further investigated and pleads for translational studies addressing the potential impact of vector-borne diseases of human and veterinary impact through large-scale research and surveillance programmes in Corsica.

Risk factors for seasonal influenza virus detection in stools of patients consulting in general practice for acute respiratory infections in France, 2014-2016.

BACKGROUND: Previous studies reported detection of influenza RNA in stools of patients with seasonal influenza infection. While this detection may have a clinical significance, other factors may influence the stool positivity for influenza viruses. OBJECTIVES: The objective of this study was to investigate demographical, clinical, and microbiological factors which could favor the presence of influenza viral RNA in the stools of patients with laboratory-confirmed influenza infection. METHODS: Acute respiratory infection (ARI) patients were enrolled by general practitioners (GP) during two winter seasons (2014-2016). Nasopharyngeal swabs, stool specimens, and clinical data were collected. Samples were tested for 12 respiratory pathogen groups (nasopharyngeal and stool specimens) and for 12 enteric pathogens (stool specimens). RESULTS: Among the 331 patients with ARI enrolled by GP, 114 (34.4%) presented influenza infection. Influenza RNA was detected in stool samples of 21% (24/114) of the 114 stool specimens analyzed. Hospitalization (adjusted odds ratio (aOR) = 7.8 (95% confidence interval (CI)) [1.7-33.7], P = .02), age between 45 and 64 years (aOR = 4.8 [1.7-14.5], P = .01), consumption of raw shellfish and/or mollusks (aOR = 16.7 [3.6-90.9], P = .00), and use of antibiotics (aOR = 6.4 [2.1-19.8], P = .006) or antiviral treatment (aOR = 7.4 [1.9-29], P = .01) were significantly associated with an increased odds of the detection of influenza RNA in stools. Among the 24 stool samples subjected to viral isolation, no one showed virus growth. CONCLUSIONS: These findings will be useful to studies investigating the dissemination route of influenza viruses to gastrointestinal tract.

Influenza epidemics observed in primary care from 1984 to 2017 in France: A decrease in epidemic size over time.

BACKGROUND: Epidemiological analysis of past influenza epidemics remains essential to understand the evolution of the disease and optimize control and prevention strategies. Here, we aimed to use data collected by a primary care surveillance system over the last three decades to study trends in influenza epidemics and describe epidemic profiles according to circulating influenza viruses. METHODS: Influenza-like illness (ILI) weekly incidences were estimated using cases reported by general practitioners participating in the French Sentinelles network, between 1984 and 2017. Influenza epidemics were detected by applying a periodic regression to this time series. Epidemic (co-)dominant influenza virus (sub)types were determined using French virology data. RESULTS: During the study period, 297 607 ILI cases were reported allowing the detection of 33 influenza epidemics. On average, seasonal epidemics lasted 9 weeks and affected 4.1% of the population (95% CI 3.5; 4.7). Mean age of cases was 29 years. Epidemic size decreased over time by -66 cases per 100 000 population per season on average (95% CI -132; -0.2, P value = 0.049) and epidemic height decreased by -15 cases per 100 000 (95% CI -28; -2, P value = 0.022). Epidemic duration appeared stable over time. Epidemics were mostly dominated by A(H3N2) (n = 17, 52%), associated with larger epidemic size, higher epidemic peak and older age of cases. CONCLUSIONS: The declining trend in influenza epidemic size and height over the last 33 years might be related to several factors like increased vaccine coverage, hygiene improvements or changing in influenza viruses. However, further researches are needed to assess the impact of potential contributing factors to adapt influenza plans.