Publications by authors named "Maude Jacquot"
Article Synopsis
- * The pathogen's impact on oyster aquaculture in Europe worsened after its re-emergence in 2012, prompting a study on mollusc diseases across European national labs.
- * Through genomic analysis of 54 Vibrio aestuarianus strains, researchers discovered that the pathogenic subspecies has a distinct epidemic structure and identified a genetic island that provides copper resistance, aiding its adaptation and persistence in oyster populations.
The cross-species transmission (CST) of pathogens can have dramatic consequences, as highlighted by recent disease emergence events affecting human, animal and plant health. Understanding the ecological and evolutionary factors that increase the likelihood of disease agents infecting and establishing in a novel host is therefore an important research area. Previous work across different pathogens, including rabies virus (RABV), found that increased evolutionary distance between hosts reduces the frequency of cross-species transmission and of permanent host shifts.
View Article and Find Full Text PDFWhole-genome sequencing is widely used to better understand the transmission dynamics, the evolution and the emergence of new variants of viral pathogens. This can bring crucial information to stakeholders for disease management. Unfortunately, aquatic virus genomes are usually difficult to characterize because most of these viruses cannot be easily propagated .
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- The study investigates the genetic diversity of Ostreid herpesvirus 1 (OsHV-1), which causes Pacific oyster mortality syndrome, across major oyster-farming regions in France.
- Using ultra-deep sequencing and advanced bioinformatics, researchers assembled 21 new OsHV-1 genomes to analyze their genetic variations and evolutionary relationships.
- The findings indicate that the Marennes-Oléron Bay is the main source of OsHV-1 diversity, highlighting the impact of oyster transfer practices on viral dispersion and demonstrating the applicability of phylodynamic methods to DNA viruses.
Ixodes ricinus ticks (Acari: Ixodidae) are the most important vector for Lyme borreliosis in Europe. As climate change might affect their distributions and activities, this study aimed to determine the effects of environmental factors, i.e.
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- Virus outbreaks are often unpredictable, especially for DNA viruses with low mutation rates, but whole-genome sequencing can help track genetic changes over time.
- This study focuses on the Ostreid herpesvirus 1 (OsHV-1), a virus that has caused significant economic and ecological damage in Europe since its new variant emerged in 2008.
- The analysis shows enough genetic diversity and evolution in OsHV-1 over the last 30 years, with evidence of selective pressures affecting certain genomic regions and variant genotypes found within individual hosts.
Article Synopsis
- Recurrent outbreaks of bluetongue and Schmallenberg viruses have been observed in Europe, transmitted by Culicoides midges affecting livestock and wildlife.
- The study analyzed 348 Culicoides obsoletus individuals from 46 locations in France to assess genetic flow in relation to environmental factors, finding low genetic variation and a notable north-south pattern.
- Results indicate that cattle density influences the gene flow of C. obsoletus, suggesting a need for better strategies in managing vector-borne diseases due to their strong dispersal abilities.
Article Synopsis
- Virus emergence mechanisms are often unclear, making outbreaks unpredictable, as seen with the Bluetongue virus serotype 8 (BTV-8) outbreaks in Europe, which began in 2006 and re-emerged in 2015 despite prior control efforts.
- Phylogenetic analysis of 164 BTV-8 genomes revealed minimal evolutionary change between the two outbreaks, suggesting that the virus did not replicate for several years during this period.
- The researchers propose that the second outbreak may have been triggered by livestock exposure to frozen virus-contaminated materials from the earlier outbreak, underlining the need for improved disease surveillance in livestock and demonstrating the value of genomic studies in understanding infectious diseases.
Article Synopsis
- Reassortment in segmented viruses allows co-infecting strains to exchange genetic segments, leading to new virus genotypes, but its effects on transmission and diversity are not well understood.
- The study focused on the bluetongue virus (BTV), analyzing 92 genomes from India over four decades, revealing frequent reassortment and selective pressures acting on the virus.
- Findings showed a recent selective sweep on segment 5's NS1 protein driving a single variant's dominance, while diversifying selection maintained genetic diversity in other essential surface protein genes, supporting the idea that reassortment contributes to rapid changes in virus traits.
Pathogens are embedded in a complex network of microparasites that can collectively or individually alter disease dynamics and outcomes. Endemic pathogens that infect an individual in the first years of life, for example, can either facilitate or compete with subsequent pathogens thereby exacerbating or ameliorating morbidity and mortality. Pathogen associations are ubiquitous but poorly understood, particularly in wild populations.
View Article and Find Full Text PDFSpatio-temporal patterns of the spread of infectious diseases are commonly driven by environmental and ecological factors. This is particularly true for vector-borne diseases because vector populations can be strongly affected by host distribution as well as by climatic and landscape variables. Here, we aim to identify environmental drivers for bluetongue virus (BTV), the causative agent of a major vector-borne disease of ruminants that has emerged multiple times in Europe in recent decades.
View Article and Find Full Text PDFHeterogeneity within pathogen species can have important consequences for how pathogens transmit across landscapes; however, discerning different transmission routes is challenging. Here, we apply both phylodynamic and phylogenetic community ecology techniques to examine the consequences of pathogen heterogeneity on transmission by assessing subtype-specific transmission pathways in a social carnivore. We use comprehensive social and spatial network data to examine transmission pathways for three subtypes of feline immunodeficiency virus (FIV ) in African lions (Panthera leo) at multiple scales in the Serengeti National Park, Tanzania.
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- Many pathogens have multiple host species and strains, making it difficult to understand how diseases spread and how to manage risks effectively.
- The research focuses on Borrelia burgdorferi, the bacteria behind Lyme disease, by examining 488 infected ticks in France and comparing their genotypes with those from small mammals.
- The study identifies four distinct transmission cycles, with chipmunks and birds playing major roles, while native bank voles contribute minimally, highlighting significant public health implications from certain genotypes associated with Lyme disease.
Article Synopsis
- Lyme borreliosis, a common zoonotic disease in the Northern Hemisphere caused by Borrelia burgdorferi bacteria, is spread by ticks from wildlife like small mammals and birds, making it an interesting subject for studying disease patterns.
- Researchers isolated 63 strains from questing ticks in Alsace, France, where Lyme disease is prevalent, to analyze genetic isolation and found significant differences in recombination rates between species.
- The findings suggest that population genomic data can give insights into epidemiological factors, revealing higher population sizes and migration rates in B. garinii (associated with birds) compared to B. burgdorferi, which may indicate shared hosts between these lineages.
Article Synopsis
- Lyme disease is caused by Borrelia burgdorferi bacteria and is transmitted by ticks, infecting various rodent host species.
- Researchers studied the genetic variants of these bacteria from over 200 wild-caught rodents to see if certain variants are limited to specific hosts or can spread widely.
- The study found significant genetic differences among the bacterial populations in different host species, highlighting the complexity of Lyme disease transmission and the benefits of advanced sequencing techniques in understanding it.