Biology subjects

CROVILLE, G.

Publications and source records attributed to CROVILLE, G..

6 recordsLinked to original sources

bioRxiv2026

A novel coronavirus associated with enteritis in broiler chickens, France, 2025

Coronaviruses of the genus Gammacoronavirus cause major poultry diseases, including infectious bronchitis in chickens and enteritis in turkeys and guinea fowl. Until now, no enteric coronavirus distinct from infectious bronchitis virus had been reported in chickens. Between late 2024 and 2025, severe enteritis outbreaks affected broiler farms in southwestern France, causing increased mortality, wet litter, cyanosis, lethargy, ruffled feathers, and high slaughter condemnation rates. Necropsy and histopathology revealed diffuse enteritis and dehydration. Metagenomic sequencing identified abundant coronavirus reads as the only pathogenic viral signal. Whole-genome phylogeny showed a novel gammacoronavirus lineage closely related to guinea fowl coronavirus but distinct from infectious bronchitis virus and turkey coronavirus. Viral RNA was detected in enterocytes by RNAscope in situ hybridization, and electron microscopy revealed coronavirus-like particles. These findings describe a novel enteritis-associated coronavirus in broiler chickens (ChECoV), although the drivers of its host-range expansion into chickens remain to be elucidated.

microbiology↗

bioRxiv2025

Detection and isolation of H5N1 clade 2.3.4.4b high pathogenicity avian influenza virus from ticks (Ornithodoros maritimus) recovered from a naturally infected slender-billed gull (Chroicocephalus genei)

Laridae birds, such as gulls, are known reservoirs of H13 and H16 low pathogenicity avian influenza virus (LPAIV) subtypes. However, during the recent outbreaks linked to the reemergence of high pathogenicity avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b of the Goose/Guangdong lineage, European populations of Laridae birds suffered significant losses. HPAI cases were reported not only along the coastlines but also inland areas, particularly in France and Central Europe. During a diagnostic investigation of a group of Laridae birds, part of a HPAIV outbreak reported in the South of France in 2023, larval stages of Ornithodoros maritimus, a nidicolous soft tick parasitizing seabirds, were recovered from a slender-billed gull (Chroicocephalus genei). Affected birds exhibited gross and histopathological lesions consistent with systemic HPAIV infection. Immunohistochemistry revealed marked neurotropism, oculotropism and multicentric epitheliotropism. Viral isolation and sequencing analysis confirmed the presence of HPAIV H5N1 clade 2.3.4.4b in both the gull and ectoparasites, showing from 99.64% to 100% nucleotide identity across five of eight RNA segments. While additional research is needed to properly assess the vector competence of O. maritimus for HPAIV, ticks may represent an interesting non-invasive surveillance tool for these viruses. This is the first time a HPAIV has been successfully isolated from tick larvae. These findings represent a first step toward understanding the potential role played by ticks in the spread of avian influenza viruses within marine bird colonies and among other ecosystems, considering the occurrence of specific behavioral traits, such as kleptoparasitim and the position of gulls at the interface between wild and domestic species.

microbiology↗

bioRxiv2025

Duck Slurry as a Matrix for Avian Influenza Virus Surveillance and Genetic Characterization in Domestic Flocks

Avian influenza viruses (AIVs) circulate widely in domestic and wild birds and continue to pose major risks to animal and public health, in particular those of high pathogenicity (HP). Ducks play a key role in AIV ecology due to frequent subclinical infections and high viral shedding. Efficient environmental surveillance approaches are needed to complement costly individual testing, especially in the context of large-scale anti-H5 vaccination as implemented in France. We evaluated duck slurry, the wastewater produced in duck fattening units, as a matrix for AIV detection and optimized molecular protocols for sensitive molecular detection and genetic characterization. Slurry samples (n = 172) were collected from 37 duck farms in southwestern France between May 2024 and March 2025. Among several extraction strategies, RNA extraction from the solid fraction using TRIzol LS followed by magnetic bead purification yielded the highest sensitivity. Using this optimized protocol, 82% of samples tested positive for AIV RNA, with 30% of positives being H5-positive; no H7 viruses were detected. Whole-segment RT-PCR and sequencing were successful for shorter genomic segments, enabling subtype determination, although virus isolation consistently failed. These findings demonstrate that slurry is a promising matrix for AIV detection, providing valuable molecular data. Slurry-based surveillance may therefore serve as an effective complement to individual testing and improve early warning capacities for influenza surveillance in a One Health perspective. ImportanceIn France, current surveillance of high pathogenicity avian influenza in ducks relies mainly on individual swabs, which may miss subclinical or transient infections, particularly with low-pathogenicity strains. By targeting slurry, a wastewater generated in duck fattening units, we developed an affordable and practical approach for environmental surveillance. Slurry samples captured high levels of avian influenza RNA and allowed partial genomic characterization despite failed virus isolation. This strategy is directly relevant to monitoring avian influenza viruses dynamics under current anti-H5 vaccination and can be extended to other livestock systems. Duck slurry-based surveillance thus represents an efficient One Health tool to strengthen preparedness against avian influenza outbreaks.

microbiology↗

bioRxiv2025

Real-time genomic pathogen, resistance, and host range characterization from passive water sampling of wetland ecosystems

Wetland ecosystems provide interfaces for the transmission of microbial pathogens and antimicrobial resistances (AMR) between migratory birds, wild and domestic animals, and human populations. The efficient surveillance of wetlands is, however, challenging, since the typically low concentration of pathogens typically requires the sampling of large volumes of water and subsequent targeted detection, which is inherently limited to a few pathogens or AMR genes of interest. Here, we present a holistic, accessible, and cost-efficient framework to characterize the pathogen and resistance load of water sources together with their potential associated hosts by combining passive water sampling through torpedo-shaped devices with nanopore sequencing technology. We used this framework to characterize anthropogenically influenced and natural wetland ecosystems along the East Atlantic Flyway, where we obtained robust assessments of the microbial communities from long-read metagenomic and RNA virome data, and showed that anthropogenically impacted wetland ecosystems consistently exhibited higher relative abundances of pathogens and AMR genes. By focusing on avian influenza viruses (AIV), we finally highlight the additional need for targeted screening and whole-genome sequencing of pathogens of interest; we detected and characterized AIV at a third of the monitored sites, and used environmental DNA (eDNA) to explore potential animal hosts to better understand the role of wetland ecosystems as One Health interfaces. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=191 HEIGHT=200 SRC="FIGDIR/small/674394v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@1a006f2org.highwire.dtl.DTLVardef@12824c2org.highwire.dtl.DTLVardef@8554bdorg.highwire.dtl.DTLVardef@17e800e_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2024

Latest RNA and DNA nanopore sequencing allows for rapid avian influenza profiling

Avian influenza virus (AIV) currently causes a panzootic with extensive mortality in wild birds, poultry, and wild mammals, thus posing a major threat to global health and underscoring the need for efficient monitoring of its distribution and evolution. Here, we utilized a well-defined AIV strain to systematically investigate AIV characterization through rapid, portable nanopore sequencing by (i) benchmarking the performance of fully portable RNA extraction and viral detection; (ii) comparing the latest DNA and RNA nanopore sequencing approaches for in-depth AIV profiling; and (iii) evaluating the performance of various computational pipelines for viral consensus sequence creation and phylogenetic analysis. Our results show that the latest RNA-specific nanopores can accurately genomically profile AIV from native RNA while additionally detecting RNA epigenetic modifications. We further identified an optimal laboratory and bioinformatic pipeline for reconstructing viral consensus genomes from nanopore sequencing data at various rarefaction thresholds, which we validated by application to real-world environmental samples for AIV monitoring in livestock. Author SummaryWe tested portable, rapid, and easy-to-use technology to obtain more information about the potentially zoonotic RNA virus avian influenza virus, or AIV. AIV has spread globally via the migratory paths of wild birds, and endangers domestic birds, mammals, and human populations given past evidence of infections of different animal species. We here used novel genomic technology that is based on nanopores to explore the genomes of the virus; we established optimized ways of creating the viral genome by comparing different laboratory and computational approaches and the performance of nanopores that either sequence the viral RNA directly or the converted DNA. We then applied the optimized protocol to dust samples which were collected from a duck farm in France during an AIV outbreak. We showed that we were able to use the resulting data to reconstruct the relationship between the virus responsible for the outbreak and previously detected AIV. Altogether, we showed how novel easy-to-use genomic technology can support the surveillance of potentially zoonotic pathogens by accurately recreating the viral genomes to better understand evolution and transmission of these pathogens.

genomics↗

bioRxiv2023

An amplicon-based nanopore sequencing workflow for rapid tracking of avian influenza outbreaks, France, 2020-2022

During the recent avian influenza epizootics that occurred in France in 2020/21 and 2021/22, the virus was so contagiousness that it was impossible to control its spread between farms. The preventive slaughter of millions of birds consequently was the only solution available. In an effort to better understand the spread of avian influenza viruses (AIVs) in a rapid and innovative manner, we established an amplicon-based MinION sequencing workflow for the rapid genetic typing of circulating AIV strains. An amplicon-based MinION sequencing workflow based on a set of PCR primers targeting primarily the hemagglutinin gene but also the entire influenza virus genome was developed. Thirty field samples from H5 HPAIV outbreaks in France, including environmental samples, were sequenced using the MinION MK1C. A real-time alignment of the sequences with MinKNOW software allowed the sequencing run to be stopped as soon as enough data were generated. The consensus sequences were then generated and a phylogenetic analysis was conducted to establish links between the outbreaks. The whole sequence of the hemagglutinin gene was obtained for the 30 clinical samples of H5Nx HPAIV belonging to clade 2.3.4.4b. The consensus sequences comparison and the phylogenetic analysis demonstrated links between some outbreaks. While several studies have shown the advantages of MinION for avian influenza virus sequencing, this workflow has been applied exclusively to clinical field samples, without any amplification step on cell cultures or embryonated eggs. As this type of testing pipeline requires only a short amount of time to link outbreaks or demonstrate a new introduction, it could be applied to the real-time management of viral epizootics.

genomics↗