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.

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.

Molecular Detection of Spotted-Fever Group Rickettsiae in Ticks Collected from Domestic and Wild Animals in Corsica, France.

To obtain a better understanding of the current magnitude of tick-borne rickettsioses in Corsica, we used molecular methods to characterize the occurrence of Rickettsia spp. in ixodid ticks collected from domestic and wild animals. The presence of Rickettsia spp. was evaluated using real-time polymerase chain reaction targeting the gltA gene and by sequencing of gltA and ompA partial genes for species identification and phylogenetic analysis. Infection rates were calculated as the maximum-likelihood estimation (MLE) with 95% confidence intervals (CI). In total, 1117 ticks belonging to four genera (Rhipicephalus, Hyalomma, Ixodes, and Dermacentor) were collected from cattle, sheep, wild boars, and companion animals during July-August 2017 and July 2018-January 2019. Overall, Rickettsia DNA was detected in 208 of 349 pools of ticks (MLE = 25.6%, 95% CI: 22.6-28.8%). The molecular analysis revealed five different rickettsial species of the spotted-fever group (SFG). We highlighted the exclusive detection of Candidatus Ri. barbariae in R. bursa and of Ri. aeschlimanii in H. marginatum. Rickettsia slovaca was detected in D. marginatus collected from wild boars. This study provides the first evidence of the presence of Ri. monacensis in I. ricinus ticks isolated from a dog in Corsica. In conclusion, our data revealed wide dispersal of SFG Rickettsiae and their arthropod hosts in Corsica, highlighting the need for surveillance of the risk of infection for people living and/or working close to infected or infested animals.

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.