Biology subjects

Boue, F.

Publications and source records attributed to Boue, F..

5 recordsLinked to original sources

bioRxiv2024

Infectious potential and circulation of SARS-CoV-2 in wild rats

Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, a wide range of animal species (pets, mink...) have been naturally infected with this betacoronavirus. The emergence of new variants has increased the ability of SARS-CoV-2 to infect species that were not susceptible to the "original" SARS-CoV-2, such as mice and rats. This work attempted to evaluate the role of urban rats in the SARS-CoV-2 transmission by combining surveillance studies of rat populations in urban environments, in vivo experimental inoculation of SARS-CoV-2 and comparative viral-receptor interaction in silico analyses. We studied the circulation of SARS-CoV-2 in wild Rattus norvegicus (n=401) captured in urban areas and sewage systems of several French cities. Except for 3 inconclusive samples (2/75 from Bordeaux and 1/261 from Lyon) none of the 353 sera tested showed anti-SARS-CoV-2 antibodies by microsphere immunoassay. However, the 3 inconclusive sera samples were negative by virus neutralisation assay. No SARS-CoV-2 viral RNA was detected in all lungs collected from the 401 captured urban brown rats. In complement, four rat groups (two wild-type colonies, Rattus norvegicus and Rattus rattus, and two laboratory strains, Sprague-Dawley and Wistar) were inoculated with the SARS-CoV-2 Omicron BA.5. At 4 days post-inoculation, no infectious viral particles were detected in the lungs and upper respiratory tract (URT) while viral RNA was detected at a low level only in the URT of all groups. In addition, seroconversion was observed 14 days after inoculation in the four groups. By molecular modelling, the Omicron BA.5 receptor binding domain (RBD) had lower affinities for Rattus norvegicus and Rattus rattus ACE2 than Homo sapiens ACE2. Based on these results the SARS-CoV-2 Omicron BA.5 was unable to infect laboratory and wild type rats. In addition, Rattus norvegicus collected for this study in different areas of France were not infected with SARS-CoV-2.

microbiology↗

bioRxiv2024

Detection of Echinococcus spp. and other taeniid species in lettuces and berries: two international multicenter studies from the MEmE project

Cystic and alveolar echinococcosis are severe zoonotic diseases characterized by long asymptomatic periods lasting months or years. Viable Echinococcus eggs released into the environment through the feces of canids can infect humans through accidental ingestion via hand-to-mouth contact or consumption of contaminated food or water. Both Echinococcus multilocularis and Echinococcus granulosus sensu lato are considered as foodborne parasites. However, when considering possible pathways of human infection, it appears that food and water-borne related variables do not significantly increase the risk of infection. Providing evidence-based data for the presence of DNA and, potentially, eggs in fresh produce is crucial in understanding foodborne transmission of Echinococcus spp. to humans. Two multicenter and multicountry studies were conducted within the One Health EJP framework to estimate the proportion of lettuces and berries contaminated by E. multilocularis, E. granulosus s.l., and other taeniid DNAs from 12 European countries, Tunisia and Pakistan. A total of 1,117 lettuces, 300 strawberries and 130 blueberries samples were collected and analyzed by washing, sequential sieving and real-time PCRs. Echinococcus multilocularis DNA was detected in 1.2% (7/570) of samples tested from the seven European endemic areas and in 2% (2/100) from Pakistan. In the five European endemic countries for E. granulosus s.l., E. granulosus sensu stricto DNA was identified in 1.3% of lettuces (9/695). The proportion of lettuces contaminated by E. granulosus sensu stricto DNA was 12% (9/75) in Tunisia and 4% (4/100) in Pakistan. Regarding berries, E. multilocularis DNA was detected in 5.4% of strawberries (n=11/202), 7.3% of blueberries (6/82) from the seven European endemic countries and 56% of blueberries (14/25) from Pakistan. High contamination rates of E. granulosus s.s were found outside of Europe, with 12.0% in blueberries (3/25) from Pakistan and 81.3%. DNA in strawberries (13/16) from Tunisia. The total contamination rate of all taeniid species DNA in lettuces (5.3%; 59/1,117) and berries (12.1%; 58/480) suggests that the transfer of taeniid eggs from carnivore feces to food is not uncommon. Although we assume that eggs are the source of the DNA detected in this study, the viability of such eggs is unknown. The detection of Echinococcus species in lettuces and berries suggests a potential risk of foodborne human infection. The relative contribution of this risk remains to be estimated. Further studies on food and environmental contamination are necessary to cover different epidemiological contexts and social habits, leading to a better understanding of human infections by Echinococcus eggs.

microbiology↗

bioRxiv2023

Investigations on SARS-CoV-2 and other coronaviruses in mink farms in France at the end of the first year of COVID-19 pandemic

Soon after the beginning of the COVID-19 pandemic in early 2020, the Betacoronavirus SARS-CoV-2 infection of several mink farms breeding American minks (Neovison vison) for fur was detected in several countries of Europe. The risk of a new reservoir formation and of a reverse zoonosis from minks was then a major concern. The aim of this study was to investigate the four French mink farms for the circulation of SARS-CoV-2 at the end of 2020. The investigations took place during the slaughtering period thus facilitating different types of sampling (swabs and blood). In one of the four mink farms, 96.6% of serum samples were positive in SARS-CoV-2 ELISA coated with purified N protein recombinant antigen and 54 out of 162 (33%) pharyngo-tracheal swabs were positive by RT-qPCR. The genetic variability among 12 SARS-CoV-2 genomes sequenced in this farm indicated the co-circulation of several lineages at the time of sampling. All SARS-CoV-2 genomes detected were nested within the 20A clade (Nextclade), together with SARS-CoV-2 genomes from humans sampled at the same period. The percentage of SARS-CoV-2 seropositivity by ELISA varied between 0.5 and 1.2% in the three other farms. Interestingly, among these three farms, 11 pharyngo-tracheal swabs and 3 fecal pools from two farms were positive by end-point RT-PCR for an Alphacoronavirus highly similar to a mink coronavirus sequence observed in Danish farms in 2015. In addition, a mink Caliciviridae was identified in one of the two positive farms for Alphacoronavirus. The clinical impact of these unapparent viral infections is not known. The co-infection of SARS-CoV-2 with other viruses in mink farms could contribute to explain the diversity of clinical symptoms noted in different infected farms in Europe. In addition, the co-circulation of an Alphacoronavirus and SARS-CoV-2 within a mink farm would increase potentially the risk of viral recombination between alpha and betacoronaviruses already suggested in wild and domestic animals, as well as in humans. Author summaryFrance is not a country of major mink fur production. Following the SARS-CoV-2 contamination of mink farms in Denmark and the Netherlands, the question arose for the four French farms. The investigation conducted at the same time in the four farms revealed the contamination of one of them by a variant different from the one circulating at the same time in Denmark and the Netherlands mink farms. Investigation of three other farms free of SARS-CoV-2 contamination revealed the circulation of other viruses including a mink Alphacoronavirus and Caliciviridae, which could modify the symptomatology of SARS-CoV-2 infection in minks.

microbiology↗

bioRxiv2021

Intranasal type I interferon treatment is beneficial only when administered before clinical signs onset in the SARS-CoV-2 hamster model

Impaired type I interferons (IFNs) production or signaling have been associated with severe COVID-19, further promoting the evaluation of recombinant type I IFNs as therapeutics against SARS-CoV-2 infection. In the Syrian hamster model, we show that intranasal administration of IFN- starting one day pre-infection or one day post-infection limited weight loss and decreased viral lung titers. By contrast, intranasal administration of IFN- starting at the onset of symptoms three days post-infection had no impact on the clinical course of SARS-CoV-2 infection. Our results provide evidence that early type I IFN treatments are beneficial, while late interventions are ineffective, although not associated with signs of enhanced disease. One Sentence SummaryThe timing of type I interferon treatment is a critical determinant of its efficacy against SARS-CoV-2 infection.

microbiology↗

bioRxiv2020

Hamster and ferret experimental infection with intranasal low dose of a single strain of SARS-CoV-2

Understanding the pathogenesis of the SARS-CoV-2 infection is key to develop preventive and therapeutic strategies against COVID-19, in the case of severe illness but also when the disease is mild. The use of appropriate experimental animal models remains central in the in-vivo exploration of the physiopathology of infection and antiviral strategies. This study describes SARS-CoV-2 intra-nasal infection in ferrets and hamsters with low doses of low-passage SARS-CoV-2 clinical French isolate UCN19, describing infection levels, excretion, immune responses and pathological patterns in both animal species. Individual infection with 103 pfu SARS-CoV-2 induced a more severe disease in hamsters than in ferrets. Viral RNA was detected in the lungs of hamsters but not of ferrets and in the brain (olfactive and/or spinal bulbs) of both species. Overall, the clinical disease remained mild, with serological responses detected from 7 days and 10 days post inoculation in hamsters and ferrets respectively. Virus became undetectable and pathology resolved within 14 days. The kinetics and levels of infection can be used in ferrets and hamsters as experimental models for understanding the pathogenicity of SARS-CoV-2, and testing the protective effect of drugs.

microbiology↗