Biology subjects

Mavingui, P.

Publications and source records attributed to Mavingui, P..

10 recordsLinked to original sources

bioRxiv2025

Bat things come in threes: within-host dynamics of herpesvirus triple infection in bats

Understanding viral community ecology in bats is essential for elucidating shedding patterns and the drivers of co-infections. In this study, we explore the genetic diversity and within-host dynamics of herpesviruses (HSV) in Mormopterus francoismoutoui, a tropical insectivorous bat endemic to Reunion Island. Over three consecutive years, we collected saliva samples from seven roosts, including repeated samples from recaptured individuals. Illumina sequencing of HSV PCR-positive samples revealed a high diversity of strains (n = 20), belonging to alpha, beta and gamma-HSV subfamilies. Co-infection was frequent, with 44% of bats shedding strains from all three subfamilies. While most shedding patterns with different subfamilies appeared random, our results suggested a negative influence of gamma-HSV occurrence of the probability of co-shedding alpha-HSV. We also demonstrated a lower HSV diversity in juveniles as compared to adult bats, while pregnancy appeared to increase viral diversity--although this requires further confirmation. Longitudinal recaptures of bats revealed an accumulation of multiple HSV latent-infections over life, as the probability to be infected with a new subfamily increased with time interval between recaptures. Within-host strain dynamics were highly variable, with 79% of bats showing fluctuations in strain diversity over time--either gaining or losing strains--consistent with latency and reactivation mechanisms. These findings provide new insights into the ecological and evolutionary dynamics of herpesviruses in wild bat populations.

evolutionary biology↗

bioRxiv2024

Development of the Incompatible Insect Technique targeting Aedes albopictus: introgression of a wild nuclear background restores the performance of males artificially infected with Wolbachia

The bacterium Wolbachia pipientis is increasingly studied for its potential use in controlling insect vectors or pests due to its ability to induce Cytoplasmic Incompatibility (CI). CI can be exploited by establishing an opportunistic Wolbachia infection in a targeted insect species through trans-infection and then releasing the infected males into the environment as sterilizing agents. Several host life history traits (LHT) have been reported to be negatively affected by artificial Wolbachia infection. Wolbachia is often considered as the causative agent of these detrimental effects, and the importance of the hosts genetic origins in the outcome of trans-infection is generally overlooked. In this study, we investigated the impact of host genetic background using an Aedes albopictus line recently trans-infected with wPip from Culex pipiens mosquito, which exhibited some fitness costs. We measured several LHTs including fecundity, egg hatch rate and male mating competitiveness in the incompatible line after four rounds of introgression aiming at restoring genetic diversity in the nuclear genome. Our results show that introgression with a wild genetic background restored most fitness traits and conferred mating competitiveness comparable to that of wild males. Finally, we show that introgression leads to faster and stronger population suppression under laboratory conditions. Overall, our data support that host genome plays a decisive role in determining the fitness of Wolbachia infected incompatible males. ImportanceThe bacterium Wolbachia pipientis is increasingly used to control insect vectors and pests through the Incompatible Insect Technique (IIT) inducing a form of conditional sterility when a Wolbachia-infected male mates with an uninfected or differently infected female. Wolbachia artificial trans-infection has been repeatedly reported to affect mosquitoes LHTs, which may in turn compromise the efficiency of IIT. Using a tiger mosquito (Aedes albopictus) line recently trans-infected with a Wolbachia strain from Culex pipiens and displaying reduced fitness, we show that restoring genetic diversity through introgression significantly mitigated the fitness costs associated with Wolbachia trans-infection. This was further demonstrated through experimental population suppression, showing that introgression is required to achieve mosquito population suppression under laboratory conditions. These findings are significant for the implementation of IIT programs, as an increase in female fecundity and male performance improves mass rearing productivity as well as the sterilizing capacity of released males.

bioengineering↗

bioRxiv2024

Role of individual and population heterogeneity in shaping dynamics of multi-pathogen excretion in an island endemic bat

Understanding processes driving pathogen transmission in bats is critical to prevent spillovers and emergence events. Although substantial research has addressed this topic, few studies have directly examined shedding dynamics (as opposed to serological studies) and co-infection patterns using fine-scale spatio-temporal datasets. Here, based on the monitoring of 5,714 Reunion free-tailed bats (Mormopterus francoismoutoui) in 17 roosts over 24 months, we studied the co-shedding dynamics of paramyxoviruses (PMV) and Leptospira bacteria (LEPTO) in urine, and herpesviruses (HSV) in saliva. We evidenced all year long shedding with high prevalence of all three infectious agents (37% - 87%), as well as an exceptionally high level of co-shedding (59%), with both positive and negative interactions between infectious agents. Shedding patterns displayed temporal synchrony among roosts, with a peak during summer months, but were not influenced by roost size. Repeated shedding in recaptured bats supports within-host persistence, though underlying mechanisms remain to be identified. Our results also showed rapid HSV infection of juveniles (< 6 months), and suggest longer protection of juveniles by maternal antibodies for PMV and LEPTO. Reproductive individuals (both during the pregnancy and mating) were associated to increased PMV and LEPTO shedding, which can result from tradeoffs between reproduction and infection in both sexes, and/or an age-related bias with the progressive infection of older juveniles during reproductive periods. This study highlights the significance of persistent shedding of multiple pathogens, including bacteria, and their intricate interactions within bat populations. Understanding how human-driven ecological changes may disrupt within-host processes and influence pathogen shedding in bats will help assessing the risk of pathogen spillover from bats to other species, including humans. Author summaryUnderstanding risks of bat-borne pathogen spillover is challenging because of the difficulty in studying shedding dynamics in wild bat populations. Here, we used an original island-endemic bat species to build up a fine-scale spatio-temporal shedding analysis of two viruses (paramyxoviruses and herpesviruses) and a bacterium (Leptospira) at both population- (roost) and individual- (through recaptured bats) levels. Shedding patterns are driven by the age of bats and associated to the reproductive periods in both females and males. Results also suggest that persistence, as well as interactions between infectious agents, are important within-host processes that contribute to the transmission of infections in bat populations. More research is essential to understand how human activities may influence these co-shedding patterns and the risk of cross- species transmission.

evolutionary biology↗

bioRxiv2023

Stuck on a small tropical island: wide in-situ diversification of an urban-dwelling bat

Bats are often the only mammals naturally colonizing isolated islands and are thus an excellent model to study evolutionary processes of insular ecosystems. Here, we studied the Reunion free-tailed bat (Mormopterus francoismoutoui), an endemic species to Reunion Island that has adapted to urban settings. At regional scale, we investigated the evolutionary history of Mormopterus species, as well as on Reunion Island sex-specific and seasonal patterns of genetic structure. We used an extensive spatio-temporal sampling including 1,136 individuals from 18 roosts and three biological seasons (non-reproductive/winter, pregnancy/summer, and mating), with additional samples from Mormopterus species from neighbouring islands (M. jugularis of Madagascar and M. acetabulosus of Mauritius). Complementary information gathered from both microsatellite and mitochondrial markers revealed a high genetic diversity but no signal of spatial genetic structure and weak evidence of female philopatry. Regional analysis suggests a single colonization event for M. francoismoutoui, dated around 175,000 years ago, and followed by in-situ diversification and the evolution of divergent ancestral lineages, which today form a large metapopulation. Population expansion was relatively ancient (55,000 years ago) and thus not linked to human colonization of the island and the availability of new anthropic day-roost sites. Discordant structure between mitochondrial and microsatellite markers suggests the presence of yet-unknown mating sites, or the recent evolution of putative ecological adaptations. Our study illustrates how understanding mechanisms involved in speciation can be challenging and the importance of both mitochondrial and nuclear DNA in resolving the wide in-situ diversification of an urban-dwelling bat, endemic to a small island.

genetics↗

bioRxiv2022

Synchronicity of viral shedding in molossid bat maternity colonies

Infection dynamics in vertebrates are driven by biological and ecological processes. For bats, population structure and reproductive cycles have major effects on RNA virus transmission. On Reunion Island, previous studies have shown that parturition of pregnant females and aggregation of juvenile Reunion free-tailed bats (Mormopterus francoismoutoui) are associated to major increase in the prevalence of bats shedding viruses. The synchronicity of such shedding pulses, however, is yet to be assessed, between viruses but also maternity colonies. Based on 3422 fresh faeces collected every two to five weeks during four consecutive birthing seasons, we report the prevalence of bats shedding astroviruses (AstVs), coronaviruses (CoVs), and paramyxoviruses (PMVs) in two maternity colonies on Reunion Island. We found that the proportion of bats shedding viruses is highly influenced by sampling collection dates, and therefore by the seasonality of parturition. We highlight that virus shedding patterns are reproducible among years and colonies for CoVs and at a lesser extent for PMVs, but not for AstVs. We also report 1% of bats harbouring double infections, mostly CoVs and PMVs, but none shedding simultaneously AstVs, CoVs and PMVs.

ecology↗

bioRxiv2021

Tracking animal reservoirs of pathogenic Leptospira: the right test for the right claim.

Leptospirosis, caused by a pathogenic Leptospira bacteria, is the most prevalent zoonosis worldwide and in this context has been extensively investigated through a One Health framework. Diagnosis of human leptospirosis includes molecular and serological tools, with serological Microscopic Agglutination Test (MAT) still being considered as a gold standard. Mammals considered as biological reservoirs include species or populations that are able to maintain chronic infection and shed the bacteria via their urine in the environment. Leptospira bacteria are often investigated using the same diagnosis tool, serological MAT. However, MAT testing of putative animal reservoirs can lead to mis-interpretations as it can signal previous infection and not necessarily bring in robust information regarding the capacity of such sero-positive animals to maintain chronic infection. We use previously published data and present new results on introduced and endemic small mammals to show that MAT should not be used for the identification of reservoirs. By contrast, serological data are informative on the level of exposure of animals occupying a specific environment. Finally, we present a sequential methodology to investigate human leptospirosis in a One Health framework that associates molecular detection in humans and animals, together with MAT of human samples using Leptospira isolates obtained from reservoir animals occurring in the same environment.

microbiology↗

bioRxiv2020

Partial RdRp sequences offer a robust method for Coronavirus subgenus classification

The recent reclassification of the Riboviria, and the introduction of multiple new taxonomic categories including both subfamilies and subgenera for coronaviruses (family Coronaviridae, subfamily Orthocoronavirinae) represents a major shift in how official classifications are used to designate specific viral lineages. While the newly defined subgenera provide much-needed standardisation for commonly cited viruses of public health importance, no method has been proposed for the assignment of subgenus based on partial sequence data, or for sequences that are divergent from the designated holotype reference genomes. Here, we describe the genetic variation of a partial region of the coronavirus RNA-dependent RNA polymerase (RdRp), which is one of the most used partial sequence loci for both detection and classification of coronaviruses in molecular epidemiology. We infer Bayesian phylogenies from more than 7000 publicly available coronavirus sequences and examine clade groupings relative to all subgenus holotype sequences. Our phylogenetic analyses are largely coherent with genome-scale analyses based on designated holotype members for each subgenus. Distance measures between sequences form discrete clusters between taxa, offering logical threshold boundaries that can attribute subgenus or indicate sequences that are likely to belong to unclassified subgenera both accurately and robustly. We thus propose that partial RdRp sequence data of coronaviruses is sufficient for the attribution of subgenus-level taxonomic classifications and we supply the R package, "MyCoV", which provides a method for attributing subgenus and assessing the reliability of the attribution. Importance StatementThe analysis of polymerase chain reaction amplicons derived from biological samples is the most common modern method for detection and classification of infecting viral agents, such as Coronaviruses. Recent updates to the official standard for taxonomic classification of Coronaviruses, however, may leave researchers unsure as to whether the viral sequences they obtain by these methods can be classified into specific viral taxa due to variations in the sequences when compared to type strains. Here, we present a plausible method for defining genetic dissimilarity cut-offs that will allow researchers to state which taxon their virus belongs to and with what level of certainty. To assist in this, we also provide the R package MyCoV which classifies user generated sequences.

evolutionary biology↗

bioRxiv2019

Astrovirus in Reunion Free-tailed Bat (Mormopterus francoismoutoui)

Astroviruses (AstVs) are RNA viruses infecting of a large diversity of avian and mammalian species, including bats, livestock, and humans. We investigated AstV infection in a free-tailed bat species, Mormopterus francoismoutoui, endemic to Reunion Island. A total of 380 guano samples were collected in a maternity colony during 38 different sampling sessions, from June 21st 2016 to September 4th 2018. Each sample was tested for the presence of the AstV RNA-dependent RNA-polymerase (RdRp) gene using a pan-AstV semi-nested polymerase chain reaction assay. In total, 27 guano samples (7.1%) tested positive, with high genetic diversity of the partial RdRp gene sequences among positive samples. A phylogenetic analysis further revealed that the detected viruses were genetically related to AstVs reported in rats, reptiles, dogs, and pigs, but did not cluster with AstVs commonly found in bats. Although more investigations need to be conducted to assess the prevalence of infected bats in the studied population, our findings show that Reunion free-tailed bats are exposed to AstVs, and suggest that cross-species transmission may occur with other hosts sharing the same habitat.

ecology↗

bioRxiv2019

Bat coronavirus phylogeography in the western Indian Ocean

Bats provide key ecosystem services such as crop pest regulation, pollination, seed dispersal, and soil fertilization. Bats are also major hosts for biological agents responsible for zoonoses, such as coronaviruses (CoVs). The islands of the Western Indian Ocean are identified as a major biodiversity hotspot, with more than 50 bat species. In this study, we tested 1,013 bats belonging to 36 species from Mozambique, Madagascar, Mauritius, Mayotte, Reunion Island and Seychelles, based on molecular screening and partial sequencing of the RNA-dependent RNA polymerase gene. In total, 88 bats (8.7%) tested positive for coronaviruses, with higher prevalence in Mozambican bats (20.5% {+/-} 4.9%) as compared to those sampled on islands (4.5% {+/-} 1.5%). Phylogenetic analyses revealed a large diversity of - and {beta}-CoVs and a strong signal of co-evolution between CoVs and their bat host species, with limited evidence for host-switching, except for bat species sharing day roost sites. ImportanceThis is the first study to report the presence of coronaviruses (CoVs) in bats in Mayotte, Mozambique and Reunion Island, and in insectivorous bats in Madagascar. Eight percent of the tested bats were positive for CoVs, with higher prevalence in continental Africa than on islands. A high genetic diversity of - and {beta}-CoVs was found, with strong association between bat host and virus phylogenies, supporting a long history of co-evolution between bats and their associated CoVs in the Western Indian Ocean. These results highlight that strong variation between islands does exist and is associated with the composition of the bat species community on each island. Future studies should investigate whether CoVs detected in these bats have a potential for spillover in other hosts.

evolutionary biology↗

bioRxiv2018

Construction of a Genetic Sexing Strain for Aedes albopictus: a promising tool for the development of sterilizing insect control strategies targeting the tiger mosquito

BackgroundAedes albopictus is an invasive mosquito species of global medical concern as its distribution has recently expanded to Africa, the Americas and Europe. In the absence of prophylaxis protecting human populations from emerging arboviruses transmitted by this mosquito species, the most straightforward control measures rely on the suppression or manipulation of vector natural populations. A number of environmental-friendly methods using innundative releases of sterilizing males are currently under development. However, these strategies are still lacking an efficient sexing method required for mass production of males.\n\nResultsWe present the first Genetic Sexing Strain (GSS) in Ae. albopictus, hereafter referred as TiCoq, obtained by sex linkage of rdl gene conferring dieldrin resistance. Hatching rate, larval survival and sex ratio were followed during twelve generations. The use of dieldrin at third larval stage allowed selecting 98% of males on average.\n\nConclusionA good production rate of TiCoq males makes this GSS suitable for any control method based on mass production of Ae. albopictus sterilizing males. Despite limitations resulting from affected egg hatch as well as the nature of the used insecticide, the construction of this GSS paves the way for industrial sex separation of Ae. albopictus.

genetics↗