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Gosselin-Grenet, A.-S.

Publications and source records attributed to Gosselin-Grenet, A.-S..

5 recordsLinked to original sources
bioRxiv2026

Stranger Swings: Temperature-Dependent Upsides and Downsides of a Densovirus in Aedes albopictus

Vector-borne diseases remain a significant global health concern, with the invasive mosquito Aedes albopictus playing a key role in the transmission of arboviruses including dengue, chikungunya, and Zika viruses. As this species expands in novel territories, effective vector control strategies are increasingly critical. Densoviruses (DVs) have emerged as potential biological control agents, either through direct pathogenic effects on mosquito populations or via paratransgenesis. However, the influence of combined environmental factors, such as temperature and densovirus infection on mosquito life-history traits remains largely unexplored. In this study, we investigated the effects of different temperatures (28{degrees}C, 31{degrees}C, and 34{degrees}C) and exposure to the densovirus AalDV2 on the survival of Ae. albopictus and on several mosquito life-history traits including its development time, size and symmetry at adult stage. Larvae were individually reared under controlled conditions and exposed to AalDV2 or a control treatment. Temperature had a strong nonlinear effect on survival, with dramatic mortality increases at 34{degrees}C. Unexpectedly, AalDV2-infected larvae showed significantly higher survival than controls at this extreme temperature, suggesting a protective effect under thermal stress. Across all temperatures, viral infection delayed pupation in a sex-dependent manner, with females experiencing greater delays and reduced adult wing size. Quantitative PCR revealed high infection rates (>96%) across all conditions with a viral load increasing with higher temperature in a sex-dependent manner. Our findings reveal a paradoxical outcome: while AalDV2 imposes fitness costs through delayed development and reduced body size, it confers an unexpected survival advantage at the extreme temperature. This represents the first documentation of temperature-dependent protective effects by an entomopathogenic virus in mosquitoes, challenging conventional assumptions about pathogen impacts. These results have critical implications for vector biocontrol strategies in a warming climate, as densovirus deployment could inadvertently enhance mosquito resilience in heat-stressed regions. Further research is needed to elucidate the underlying mechanisms and assess the impact on mosquito population dynamics.

evolutionary biology↗
bioRxiv2022

Structural variation turnovers and defective genomes: key drivers for the in vitro evolution of the large double-stranded DNA koi herpesvirus (KHV)

AO_SCPLOWBSTRACTC_SCPLOWStructural variations (SVs) constitute a significant source of genetic variability in virus genomes. Yet knowledge about SV variability and contribution to the evolutionary process in large double-stranded (ds)DNA viruses is limited. Cyprinid herpesvirus 3 (CyHV-3), also commonly known as koi herpesvirus (KHV), has the largest dsDNA genome within herpesviruses. This virus has become one of the biggest threats to common carp and koi farming, resulting in high morbidity and mortalities of fishes, serious environmental damage, and severe economic losses. A previous study analyzing CyHV-3 virulence evolution during serial passages onto carp cell cultures suggested that CyHV-3 evolves, at least in vitro, through an assembly of haplotypes that alternatively become dominant or under-represented. The present study investigates the SV diversity and dynamics in CyHV-3 genome during 99 serial passages in cell culture using, for the first time, ultra-deep whole-genome and amplicon-based sequencing. The results indicate that KHV polymorphism mostly involves SVs. These SVs display a wide distribution along the genome and exhibit high turnover dynamics with a clear bias towards inversion and deletion events. Analysis of the pathogenesis-associated ORF150 region in ten intermediate cell passages highlighted mainly deletion, inversion and insertion variations that deeply altered the structure of ORF150. Our findings indicate that SV turnovers and defective genomes represent key drivers in the viral population dynamics and in vitro evolution of KHV. Thus, the present study can contribute to the basic research needed to design safe live-attenuated vaccines, classically obtained by viral attenuation after serial passages in cell culture.

genomics↗
bioRxiv2020

Mosquito densoviruses: the revival of a biological control agent against urban Aedes vectors of arboviruses

Urban Aedes mosquitoes are vectors of many viruses affecting human health such as Dengue, Chikungunya and Zika viruses. Insecticide resistance and environmental toxicity risks hamper the effectiveness of chemical control against these mosquito vectors. Alternative control methods, such as the use of mosquito-specific entomopathogenic viruses should be explored. Numerous studies have focused on evaluating the potential of different densoviruses species as biological control agent. However, knowledge on the extent of inter- and intra-specific variations in the susceptibility of Aedes mosquitoes to infection by different densoviruses remains insufficient. In this study, we compared infection and mortality rates induced by the Aedes albopictus densovirus 2 in different strains of Aedes albopictus and Aedes aegypti mosquitoes. The two Aedes species were different in terms of susceptibility to viral infection. Under laboratory conditions, Aedes albopictus densovirus 2 appeared more virulent for the different strains of Aedes aegypti tested than for those of Aedes albopictus. In addition, we also found significant intra-specific variation in infection and mortality rates. Thus, although even if Aedes albopictus densoviruses could be powerful biocontrol agents used in the management of urban Aedes populations, our results also call into question the use of single viral isolate as biocontrol agents.

microbiology↗
bioRxiv2018

Sharing cells with Wolbachia: the transovarian vertical transmission of Culex pipiens densovirus

Originality-Significance StatementThis contribution provides a window into the study of a densovirus called CpDV infecting Culex pipiens mosquitoes. The originality of the study lies in the fact that CpDV, a DNA virus, was to date almost unstudied, its interaction with its hosts and its transmission mode were unknown. Considering that all Cx. pipiens are infected with Wolbachia, we studied the influence of this bacterial endosymbiont on CpDV density and transmission. Although Wolbachia-RNA virus interactions, especially in non-native Wolbachia-host associations have been widely studied, Wolbachia-DNA virus interactions were rarely investigated.\n\nIn this natural tripartite Cx. pipiens-Wolbachia-CpDV system: O_LIWe revealed the wide prevalence of CpDV, mostly at low densities, in Cx. pipiens laboratory lines.\nC_LIO_LIWe monitored CpDV presence in several cell types in ovaries including the oocytes where they co-exist with the bacterial endosymbiont Wolbachia.\nC_LIO_LIWe demonstrated that CpDV density in ovaries was influenced by Wolbachia presence and strain variations\nC_LIO_LIWe studied CpDV vertical transmission depending on Wolbachia presence and strain variations\nC_LI\n\nWe report for the first time the occurrence of widely distributed covert CpDV infections in Cx. pipiens laboratory colonies. CpDV is maintained by both vertical and horizontal transmission and under the influence of the vertically transmitted bacterial endosymbiont Wolbachia. Taken together our results suggest that CpDV could be very prevalent in nature putatively influencing natural Cx. pipiens populations dynamics.\n\nSUMMARYCulex pipiens densovirus (CpDV), a single stranded DNA virus, has been isolated from Culex pipiens mosquitoes but differs from other mosquito densoviruses in terms of genome structure and sequence identity. Its transmission from host to host, the nature of its interactions with both its host and hosts endosymbiotic bacteria Wolbachia are not known. Here we report the presence of CpDV in the ovaries and eggs of Cx. pipiens mosquitoes in close encounters with Wolbachia. In the ovaries, CpDV quantity significantly differed between mosquito lines harboring different strains of Wolbachia and these differences were not linked to variations in Wolbachia densities. CpDV was vertically transmitted in all laboratory lines to 17%-20% of the offspring. For some females, however, the vertical transmission reached 90%. Antibiotic treatment that cured the host from Wolbachia also significantly affected both CpDV quantity and vertical transmission suggesting an impact of host microbiota, including Wolbachia, on CpDV transmission. Overall our results show that CpDV is transmitted vertically via transovarian path along with Wolbachia with which it shares the same cells. Our results are primordial to understand the dynamics of densovirus infection, their persistence and spread in populations considering their potential use in the regulation of mosquito vector populations.

microbiology↗