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. In particular, data for West African countries are extremely scarce. Here, we took advantage of an extensive survey of urban rodents in Niamey, Niger, in order to look for rodent-borne pathogenic[i] Leptospira[/i] species presence and distribution across the city. To do so, we used high throughput bacterial 16S-based metabarcoding, [i]lipL32[/i] gene-targeting RT-PCR, rrs gene sequencing and VNTR typing as well as GIS-based multivariate spatial analysis. Our results show that leptospires seem absent from the core city where usual [i]Leptospira[/i] reservoir rodent species (namely [i]R. rattus[/i] and [i]M. natalensis[/i]) are yet abundant. On the contrary, [i]L. kirschneri[/i] was detected in [i]Arvicanthis niloticus[/i] and [i]Cricetomys gambianus[/i], two rodent species that are restricted to irrigated cultures within the city. Moreover, the VNTR profiles showed that rodent-borne leptospires in Niamey belong to previously undescribed serovars. Altogether, our study points towards the importance of market gardening in maintain and circulation of leptospirosis within Sahelian cities. In Africa, irrigated urban agriculture constitutes a pivotal source of food supply, especially in the context of the ongoing extensive urbanization of the continent. With this in mind, we speculate that leptospirosis may represent a zoonotic disease of concern also in arid regions that would deserve to be more rigorously surveyed, especially in urban agricultural settings

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 (Mus musculus domesticus) 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. Our findings first showed an unexpectedly rapid spread of the house mouse, which reached even remote areas where native species would have been expected to dominate the rodent communities. They also strengthened previous insights suggesting a role of helminths in the invasion success of the house mouse, such as: (i) low infestation rates of invading mice by the exotic nematode Aspiculuris tetraptera at invasion fronts except in a single zone where the establishment of the house mouse could be older than initially thought, which was consistent with the "enemy release" hypothesis; and (ii) higher infection rates by the local cestode Mathevotaenia symmetrica in native rodents with long co-existence history with invasive mice, bringing support to the "spill-back" hypothesis. Therefore, "enemy release" and "spill-back" mechanisms should be seriously considered when explaining the invasion success of the house mouse provided further experimental works demonstrate that involved GIHs affect rodent fitness or exert selective pressures. Next steps should also include evolutionary, immunological, and behavioral perspectives to fully capture the complexity, causes and consequences of GIH variations along these invasion routes

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"). We focused on gastrointestinal helminth communities to determine whether these predictions could explain the ongoing invasion success of the commensal house mouse (Mus musculus domesticus) and black rat (Rattus rattus), as well as the associated decrease in native Mastomys spp., in Senegal. For both invasive species, our results were consistent with the predictions of the enemy release hypothesis. A decrease in overall gastrointestinal helminth prevalence and infracommunity species richness was observed along the invasion gradients as well as lower specific prevalence/abundance (Aspiculuris tetraptera in Mus musculus domesticus, Hymenolepis diminuta in Rattus rattus) on the invasion fronts. Conversely, we did not find strong evidence of GIH spillover or spillback in invasion fronts, where native and invasive rodents co-occurred. Further experimental research is needed to determine whether and how the loss of gastrointestinal helminths and reduced infection levels along invasion routes may result in any advantageous effects on invader fitness and competitive advantage

Testing the 'zero-sum game' hypothesis: An examination of school health policy and practice and inequalities in educational outcomes

Background: There is recognition that health and education are intrinsically linked, through for example the World Health Organizations' Health Promoting Schools' (HPS) framework. Nevertheless, promoting health via schools is seen by some as a 'zero-sum game'; that is, schools have nothing to gain, and in fact may experience detriments to the core business of academic attainment as a result of focussing resources on health. Crucially, there is a paucity of evidence around the impacts of health and well-being policy and practice on attainment, with recent Cochrane reviews highlighting this gap. This study explored the 'zero-sum game' hypothesis among schools with varying levels of deprivation; that is, the role of health and wellbeing interventions in schools in reducing, or widening, socioeconomic inequality in educational attainment. Methods: Wales-wide, school-level survey data on health policies and practices, reflective of the HPS framework, were captured in 2016 using the School Environment Questionnaire (SEQ). SEQ data were linked with routinely collected data on academic attainment. Primary outcomes included attendance and attainment at Key Stages 3 and 4. Interaction terms were fitted to test whether there was an interaction between FSM,overall HPS activity, and outcomes. Linear regression models were constructed separately for high (>15% of pupils) and low (<15%) Free School Meal (FSM) schools, adjusting for confounders. Findings: The final analyses included 48 low and 49 high FSM secondary schools. Significant interactions were observed between FSM and overall HPS for KS3 attainment (b=0.28; 95% CI: 0.09, 0.47) and attendance(b=0.05; 95% CI: 0.02, 0.09), reflecting an association between health improvement activities and education outcomes among high, but not low FSM schools. There was no significant interaction for KS4 attainment (b=0.18; 95% CI: -0.22, 0.57).Interpretation: Our findings did not support the 'zero-sum game' hypothesis; in fact, among more deprived schools, there was a tendency for better attendance and attainment at Key Stage 3. Schools must equip students with the skills required for good physical, mental health and well-being in addition to academic and cognitive skills. The study included a large, nationally representative sample of secondary schools;however, the cross-sectional nature has implications for causality

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. Thus an easy, fast and accurate species identification tool is needed for non-systematicians to correctly identify Praomyini species. In this study we compare the usefulness of three genes (16S, Cytb, CO1) for identifying species of this tribe. A total of 426 specimens representing 40 species (sampled across their geographical range) were sequenced for the three genes. Nearly all of the species included in our study are monophyletic in the neighbour joining trees. The degree of intra-specific variability tends to be lower than the divergence between species, but no barcoding gap is detected. The success rate of the statistical methods of species identification is excellent (up to 99% or 100% for statistical supervised classification methods as the k-Nearest Neighbour or Random Forest). The 16S gene is 2.5 less variable than the Cytb and CO1 genes. As a result its discriminatory power is smaller. To sum up, our results suggest that using DNA markers for identifying species in the Praomyini tribe is a largely valid approach, and that the CO1 and Cytb genes are better DNA markers than the 16S gene. Our results confirm the usefulness of statistical methods such as the Random Forest and the 1-NN methods to assign a sequence to a species, even when the number of species is relatively large. Based on our NJ trees and the distribution of all intraspecific and interspecific pairwise nucleotide distances, we highlight the presence of several potentially new species within the Praomyini tribe that should be subject to corroboration assessments

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

Abstract 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. The specimens were labelled G. gerbillus, G. andersoni, G. nanus, G. amoenus, G. perpallidus and G. pyramidum, and molecular results mostly confirmed these assignations. The close relationship between G. nanus (Asian origin) and G. amoenus (African origin) confirmed that they represent vicariant sibling species which differentiated in allopatry on either side of the Red Sea. In the closely related G. perpallidus and G. pyramidum, specimens considered as belonging to one G. pyramidum subspecies (G. p. floweri) appeared closer to G. perpallidus suggesting that they (G. p. floweri and G. perpallidus) may represent a unique species, distributed on both sides of the Nile River, for which the correct name should be G. floweri. Furthermore, the three other G. pyramidum subspecies grouped together with no apparent genetic structure suggesting that they may not yet represent genetically differentiated lineages. This study confirms the importance of using these methods on museum samples, which can open new perspectives in this particular group as well as in other groups of interest. † William Stanley passed away in October 2015. This paper is dedicated to his memory. RESEARCH ARTICLE Launched to accelerate biodiversity research A peer-reviewed open-access journal Arame Ndiaye et al. / ZooKeys 566: 145-155 (2016) 14

Taxonomic hypotheses regarding the genus <em>Gerbillus</em> (Rodentia, Muridae, Gerbillinae) based on molecular analyses of museum specimens

International audienceMethodological 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. The specimens were labelled G. gerbillus, G. andersoni, G. nanus, G. amoenus, G. perpallidus and G. pyramidum, and molecular results mostly confirmed these assignations. The close relationship between G. nanus (Asian origin) and G. amoenus (African origin) confirmed that they represent vicariant sibling species which differentiated in allopatry on either side of the Red Sea. In the closely related G. perpallidus and G. pyramidum, specimens considered as belonging to one G. pyramidum subspecies (G. p. floweri) appeared closer to G. perpallidus suggesting that they (G. p. floweri and G. perpallidus) may represent a unique species, distributed on both sides of the Nile River, for which the correct name should be G. floweri. Furthermore, the three other G. pyramidum subspecies grouped together with no apparent genetic structure suggesting that they may not yet represent genetically differentiated lineages. This study confirms the importance of using these methods on museum samples, which can open new perspectives in this particular group as well as in other groups of interest

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. Thus, SEOV is a possible emerging zoonotic risk in Africa. Moreover, the range of SEOV could rapidly expand, and transmission to humans could increase because of host switching from the usual brown rat (Rattus norvegicus) species, which is currently invading Africa, to the more widely installed black rat (R. rattus) species. Because of rapid economic development, environmental and climatic changes, and increased international trade, strengthened surveillance is urgently needed to prevent SEOV dissemination among humans in Africa

Patterns and drivers of genetic diversity and structure in the biological control parasitoid Habrobracon hebetor in Niger

International audienceWhen a promising natural enemy of a key pest exists locally, it is a common practice in biological control (BC) to rear and release it for supplementary control in the targeted agroecosystem even though significant knowledge gaps concerning pre/post release may still exist. Incorporating genetic information into BC research fills some of these gaps. Habrobracon hebetor, a parasitoid of many economically important moths that infest stored and field crops worldwide is commonly used, particularly against the millet head miner (MHM), a key pest of millet in Sahelian countries. To advance our knowledge on how H. hebetor that occurs naturally in open-field cropping systems and grain stores as well as being mass-produced and released for MHM control, performs in millet agroecosystems in Niger we evaluated its population genetics using two mitochondrial and 21 microsatellite markers. The field samples were genetically more diverse and displayed heterozygote excess. Very few field samples had faced significant recent demographic bottlenecks. The mating system (i.e. nonrandom mating with complementary sex determination) of this species may be the major driver of these findings rather than bottlenecks caused by the small number of individuals released and the scarcity of hosts during the longlasting dry season in Niger. H. hebetor population structure was represented by several small patches and genetically distinct individuals. Gene flow occurred at local and regional scales through human-mediated and natural short-distance dispersal. These findings highlight the importance of the mating system in the genetic diversity and structure of H. hebetor populations, and contribute to our understanding of its reported efficacy against MHM in pearl millet fields

Lippens_FinalAlignment

Sequence alignment (1793 sequences, 889 bp) of the D-loop control region and flanking tRNA genes, Mus musculus domesticus: 1313 sequences published in Bonhomme et al. (2011), 361 sequences obtained from other studies (Prager et al., 1996, 1998; Gündüz et al., 2000, 2001, 2005; Ihle et al., 2006; Searle et al., 2009a, b; Jones et al., 2010; Linnenbrinck et al., 2013 ; Suzuki et al., 2013; Gabriel et al., 2015; Jones and Searle, 2015), and 119 sequences from house mice sampled in Senegal (this study