African schistosomes in small mammal communities: Perspectives from a spatio-temporal survey in the vicinity of Lake Guiers, Senegal.

Schistosomiasis is a neglected tropical disease of public health significance. In view of its elimination as a public health problem by 2030, adopting a One Health approach is necessary, considering its multidimensional nature. Animal reservoirs, in particular, pose a significant threat to schistosomiasis control in Africa and beyond.

Prevalence, genetic diversity and eco-epidemiology of pathogenic Leptospira species in small mammal communities in urban parks Lyon city, France.

Rodents are recognized as the main reservoirs of Leptospira spp. Rats, in particular, serve as hosts for the widely predominant Leptospira interrogans serovar Icterohaemorrhagiae, found worldwide. Several studies have shown the importance of other reservoirs, such as mice or hedgehogs, which harbor other leptospires' serovars.

Puumala orthohantavirus circulation in its wild reservoir, the bank vole, during the 2021 outbreak of hemorrhagic fever with renal syndrome in Jura, France.

Objective: A large and unprecedented outbreak of an attenuated form of hemorrhagic fever with renal syndrome called nephropathia epidemica (NE) and caused by Puumala virus (PUUV) occurred in 2021 in the southern Jura Mountains (France) leading to numerous hospitalizations. The aim of this study was to investigate the circulation of PUUV in its animal reservoir at the time of this outbreak.

Methods: We conjointly surveyed bank vole relative abundance, small mammal community composition, and PUUV circulation in bank voles (seroprevalence and genetic diversity) in the Jura NE epidemic area, between 2020 and 2022.

Role of Seaports and Imported Rats in Seoul Hantavirus Circulation, Africa.

Seoul orthohantavirus (SEOV) is not considered a major public health threat on the continent of Africa. However, Africa is exposed to rodentborne SEOV introduction events through maritime traffic after exponential growth of trade with the rest of the world. Serologic studies have already detected hantavirus antibodies in human populations, and recent investigations have confirmed circulation of hantavirus, including SEOV, in rat populations.

Same Invasion, Different Routes: Helminth Assemblages May Favor the Invasion Success of the House Mouse in Senegal.

Previous field-based studies have evidenced patterns in gastrointestinal helminth (GIH) assemblages of rodent communities that are consistent with "enemy release" and "spill-back" hypotheses, suggesting a role of parasites in the ongoing invasion success of the exotic house mouse () in Senegal (West Africa). However, these findings came from a single invasion route, thus preventing to ascertain that they did not result from stochastic and/or selective processes that could differ across invasion pathways. In the present study, we investigated the distribution of rodent communities and their GIH assemblages in three distinct zones of Northern Senegal, which corresponded to independent house mouse invasion fronts.

Isolation and Genetic Characterization of Puumala Orthohantavirus Strains from France.

Puumala orthohantavirus (PUUV) causes a mild form of haemorrhagic fever with renal syndrome (HFRS) called nephropathia epidemica (NE), regularly diagnosed in Europe. France represents the western frontier of the expansion of NE in Europe with two distinct areas: an endemic area (north-eastern France) where PUUV circulates in rodent populations, with the detection of many human NE cases, and a non-endemic area (south-western France) where the virus is not detected, with only a few human cases being reported. In this study, we describe the different stages of the isolation of two PUUV strains from two distinct French geographical areas: Ardennes (endemic area) and Loiret (non-endemic area).

Differential immune gene expression associated with contemporary range expansion in two invasive rodents in Senegal.

Biological invasions are major anthropogenic changes associated with threats to biodiversity and health. However, what determines the successful establishment and spread of introduced populations remains unclear. Here, we explore several hypotheses linking invasion success and immune phenotype traits, including those based on the evolution of increased competitive ability concept.

How Bank Vole-PUUV Interactions Influence the Eco-Evolutionary Processes Driving Nephropathia Epidemica Epidemiology-An Experimental and Genomic Approach.

In Europe, Puumala virus (PUUV) is responsible for nephropathia epidemica (NE), a mild form of hemorrhagic fever with renal syndrome (HFRS). Despite the presence of its reservoir, the bank vole, on most of French territory, the geographic distribution of NE cases is heterogeneous and NE endemic and non-endemic areas have been reported. In this study we analyzed whether bank vole-PUUV interactions could partly shape these epidemiological differences.

Detection and Genetic Characterization of Puumala Orthohantavirus S-Segment in Areas of France Non-Endemic for Nephropathia Epidemica.

Puumala virus (PUUV) in Europe causes nephropathia epidemica (NE), a mild form of hemorrhagic fever with renal syndrome (HFRS). The incidence of NE is highly heterogeneous spatially, whereas the geographic distribution of the wild reservoir of PUUV, the bank vole, is essentially homogeneous. Our understanding of the processes driving this heterogeneity remains incomplete due to gaps in knowledge.

Leishmania major and Trypanosoma lewisi infection in invasive and native rodents in Senegal.

Bioinvasion is a major public health issue because it can lead to the introduction of pathogens in new areas and favours the emergence of zoonotic diseases. Rodents are prominent invasive species, and act as reservoirs in many zoonotic infectious diseases. The aim of this study was to determine the link between the distribution and spread of two parasite taxa (Leishmania spp.

Ecological and sanitary impacts of bacterial communities associated to biological invasions in African commensal rodent communities.

Changes in host-parasite ecological interactions during biological invasion events may affect both the outcome of invasions and the dynamics of exotic and/or endemic infections. We tested these hypotheses, by investigating ongoing house mouse (Mus musculus domesticus) and black rat (Rattus rattus) invasions in Senegal (West Africa). We used a 16S gene rRNA amplicon sequencing approach to study potentially zoonotic bacterial communities in invasive and native rodents sampled along two well-defined independent invasion routes.

Whipworm diversity in West African rodents: a molecular approach and the description of Trichuris duplantieri n. sp. (Nematoda: Trichuridae).

Whipworms were collected from rodents (Muridae) from six West African countries: Burkina-Faso, the Islamic Republic of Mauritania, and the Republics of Benin, Guinea, Mali and Senegal. Molecular sequences (ITS-1, 5.8S and ITS-2 of the ribosomal DNA gene) and morphometric characters were analysed in Trichuris (Nematoda: Trichuridae) specimens found in seven host species: Arvicanthis niloticus, Gerbilliscus gambianus, Gerbillus gerbillus, G.

16S rRNA Amplicon Sequencing for Epidemiological Surveys of Bacteria in Wildlife.

The human impact on natural habitats is increasing the complexity of human-wildlife interactions and leading to the emergence of infectious diseases worldwide. Highly successful synanthropic wildlife species, such as rodents, will undoubtedly play an increasingly important role in transmitting zoonotic diseases. We investigated the potential for recent developments in 16S rRNA amplicon sequencing to facilitate the multiplexing of the large numbers of samples needed to improve our understanding of the risk of zoonotic disease transmission posed by urban rodents in West Africa.

Parasites and invasions: changes in gastrointestinal helminth assemblages in invasive and native rodents in Senegal.

Understanding why some exotic species become widespread and abundant in their colonised range is a fundamental issue that still needs to be addressed. Among many hypotheses, newly established host populations may benefit from a parasite loss ("enemy release" hypothesis) through impoverishment of their original parasite communities or reduced infection levels. Moreover, the fitness of competing native hosts may be negatively affected by the acquisition of exotic taxa from invaders ("parasite spillover") and/or by an increased transmission risk of native parasites due to their amplification by invaders ("parasite spillback").

Taxonomic hypotheses regarding the genus Gerbillus (Rodentia, Muridae, Gerbillinae) based on molecular analyses of museum specimens.

Methodological improvements now allow routine analyses of highly degraded DNA samples as found in museum specimens. Using these methods could be useful in studying such groups as rodents of the genus Gerbillus for which i) the taxonomy is still highly debated, ii) collection of fresh specimens may prove difficult. Here we address precise taxonomic questions using a small portion of the cytochrome b gene obtained from 45 dry skin/skull museum samples (from 1913 to 1974) originating from two African and three Asian countries.

Urban Market Gardening and Rodent-Borne Pathogenic Leptospira in Arid Zones: A Case Study in Niamey, Niger.

Leptospirosis essentially affects human following contact with rodent urine-contaminated water. As such, it was mainly found associated with rice culture, recreational activities and flooding. This is also the reason why it has mainly been investigated in temperate as well as warm and humid regions, while arid zones have been only very occasionally monitored for this disease.

Epidemiology of leptospira transmitted by rodents in southeast Asia.

Background: Leptospirosis is the most common bacterial zoonoses and has been identified as an important emerging global public health problem in Southeast Asia. Rodents are important reservoirs for human leptospirosis, but epidemiological data is lacking.

Methodology/principal Findings: We sampled rodents living in different habitats from seven localities distributed across Southeast Asia (Thailand, Lao PDR and Cambodia), between 2009 to 2010.

Mitochondrial and nuclear genes-based phylogeography of Arvicanthis niloticus (Murinae) and sub-Saharan open habitats pleistocene history.

A phylogeographic study was conducted on the Nile grass rat, Arvicanthis niloticus, a rodent species that is tightly associated with open grasslands from the Sudano-Sahelian regions. Using one mitochondrial (cytochrome b) and one nuclear (intron 7 of Beta Fibrinogen) gene, robust patterns were retrieved that clearly show that (i) the species originated in East Africa concomitantly with expanding grasslands some 2 Ma, and (ii) four parapatric and genetically well-defined lineages differentiated essentially from East to West following Pleistocene bioclimatic cycles. This strongly points towards allopatric genetic divergence within savannah refuges during humid episodes, then dispersal during arid ones; secondary contact zones would have then stabilized around geographic barriers, namely, Niger River and Lake Chad basins.

Invasion genetics of the introduced black rat (Rattus rattus) in Senegal, West Africa.

An understanding of the evolutionary history and dynamics of invasive species is required for the construction of predictive models of future spread and the design of biological management measures. The black rat (Rattus rattus) is a major vertebrate invader with a worldwide distribution. Despite the severe ecological, economic and health impacts of this species, its evolutionary history has been little studied.

Assessment of three mitochondrial genes (16S, Cytb, CO1) for identifying species in the Praomyini tribe (Rodentia: Muridae).

The Praomyini tribe is one of the most diverse and abundant groups of Old World rodents. Several species are known to be involved in crop damage and in the epidemiology of several human and cattle diseases. Due to the existence of sibling species their identification is often problematic.

Host cell/Orientia tsutsugamushi interactions: evolution and expression of syndecan-4 in Asian rodents (Rodentia, Muridae).

Scrub typhus is an acute febrile zoonotic disease and worldwide more than a billion people may be at risk for infection. Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular bacterium. Rodents are reported to be the primary reservoir hosts of the disease and according to the most recent surveys, all species within the Rattus sensu lato complex of the tribe Rattini are carriers of scrub typhus.

Molecular survey of rodent-borne Trypanosoma in Niger with special emphasis on T. lewisi imported by invasive black rats.

Invading rodent species can harbor parasites with potential transmission to native rodents and/or humans. To investigate trypanosomes prevalence in rodents, the spleen of 76 rodents from Niger identified by their karyotype was used as a DNA source for Trypanosoma detection using a newly developed qPCR assay. Of the invasive black rat, Rattus rattus, 71% (10/14) were PCR positive as well as 6% (4/62) of native African rodents.

Rodent host cell/Lassa virus interactions: evolution and expression of α-Dystroglycan, LARGE-1 and LARGE-2 genes, with special emphasis on the Mastomys genus.

Arenaviruses are usually rodent-borne viruses that constitute a major threat for human health. Among them, Lassa Fever Virus (LFV) occurs in Western Africa where it infects hundreds of thousands of people annually. According to the most recent surveys, LFV is hosted by one of the multimammate rats, Mastomys natalensis, but has never been detected in its sibling and sometimes sympatric species Mastomys erythroleucus.

Mitochondrial and chromosomal insights into karyotypic evolution of the pygmy mouse, Mus minutoides, in South Africa.

The African pygmy mouse, Mus minutoides, displays extensive Robertsonian (Rb) diversity. The two extremes of the karyotypic range are found in South Africa, with populations carrying 2n = 34 and 2n = 18. In order to reconstruct the scenario of chromosomal evolution of M.