BackgroundMany soldiers in Napoleon’s Grand Army died of infectious diseases during its retreat from Russia. Because soldiers were commonly infested

Plague is characterized by geographical foci from which it re-emerges after decades of silence, a fact currently explained by enzootic and epizootic cycles between plague-susceptible and plague-resistant rodents. To assess the potential role of soil in plague epidemiology, we experimentally investigated whether Yersinia pestis could persist alive and virulent in soil. Sterilized soil inoculated with virulent Y. pestis biotype Orientalis was regularly sampled for 40 weeks in duplicate. Each sample was observed by acridine orange staining and immunofluorescence using an anti-Y. pestis polyclonal antibody, and DNA was extracted for PCR amplification and sequencing of the Y. pestis ureD, caf1 and pla genes. All samples were inoculated onto selective agar, and samples from soil that had been incubated for 10, 60, 165, 210 and 280 days were also inoculated into each of two BALB/c female mice. The mouse experiment was performed in triplicate. Non-inoculated, sterilized soil samples were used as negative controls. Micro-organisms fluorescing orange and detected by immunofluorescence were identified as Y. pestis in all samples. They were recovered in pure agar cultures for up to 30 weeks but thereafter were contaminated with Pseudomonas spp. Soil that had been inoculated with Y. pestis proved to be fully virulent in mice, which died with Y. pestis septicaemia and multiple organ involvement. Negative control mice showed no signs of disease. These data indicate that Y. pestis biotype Orientalis can remain viable and fully virulent after 40 weeks in soil. This study is a first step on which to base further investigations of a potential telluric reservoir for Y. pestis, which could represent an alternative mechanism for the maintenance of plague foci.

Yersinia pestis has been found in human body lice during plague outbreaks. To evaluate the role that the human body louse plays as a vector of plague

One thousand one hundred and nineteen cases of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) Omicron variant cases have been diagnosed at the Institut Hospitalo‐Universitaire Méditerranée Infection, Marseille, France, between November 28, 2021, and December 31, 2021. Among the 825 patients with known vaccination status, 383 (46.4%) were vaccinated, of whom 91.9% had received at least two doses of the vaccine. Interestingly, 26.3% of cases developed SARS‐CoV‐2 infection within 21 days following the last dose of vaccine suggesting possible early production of anti‐SARS‐CoV‐2 facilitating antibodies. Twenty‐one patients have been hospitalized, one patient required intensive care, and another patient who received a vaccine booster dose died.

We aimed to investigate the first Omicron cases detected in France in order to assess case characteristics and provide supporting information on the possible impact of this variant on the healthcare system. A standardized questionnaire was used to collect information from confirmed and probable Omicron cases. Median age of 468 investigated cases was 35 years, 376 were symptomatic (89%); 64% were vaccinated with two doses and 7% had received three doses. Loss of smell and taste were reported by 8.3% and 9% of cases, respectively. Seven cases were hospitalized, three of those were unvaccinated (including two with reported precondition). No admissions to intensive care and no deaths were reported. Our results confirm a mild clinical presentation among the first Omicron cases detected in France and highlight the importance for the national COVID-19 surveillance system to quickly detect and adapt to the emergence of a new variant.