African rodents of the genus Arvicanthis are presently restricted to sub-Saharan savannas and to the Nile Valley. In contrast, their distribution during the Quaternary included most of northern Africa, leading to the emergence of local fossil species. To date, there have been no comprehensive studies of Arvicanthis populations in northern Africa, neither to clarify their taxonomy nor their paleoecology. The present study aims to explore both morphology and diet of modern and fossil Arvicanthis species using geometric morphometric and dental microwear analyses on first upper molars. The geometric morphometric analysis efficiently discriminates the studied extant and fossil Arvicanthis species and allowed for the identification of probable geographical variations within the A. niloticus group. Although all extant species of the genus Arvicanthis are predominantly grass-eaters, microwear analyses also highlighted diet differences in various modern populations of A. niloticus, as well as paleodiet inferences in the A. arambourgi fossil species, but no clear link between molar size or shape and diet can be established. This work helps set the stage for a complete revision of the fossil remains of Arvicanthis from northern African Quaternary deposits, and for a better understanding of the geographical and temporal morphological variability of this genus in Africa.

In this paper we re-describe Trichuris muris based on morphological data following isolation from two commensal rodent species, Mus musculus from Mexico and Rattus rattus from Argentina. Furthermore, we provide a molecular characterization based on mitochondrial (cytochrome c oxidase subunit 1 mitochondrial gene) and nuclear (internal transcribed spacer 2 region) markers in order to support the taxonomic identification of the studied specimens of T. muris from M. musculus. We distinguished T. muris from 29 species of Trichuris found in American rodents based on morphological and biometrical features, such as the presence of a spicular tube, length of spicule, size of proximal and distal cloacal tube and non-protrusive vulva. We suggest that spicular tube patterns can be used to classify Trichuris species in three groups. Considering that the diagnosis among the species of this genus is mainly based on morphometry, this proposal represents a relevant contribution. We provide molecular studies on two markers, making this the first contribution for T. muris in the Americas. This study makes an important contribution to the integrative taxonomy of cosmopolitan nematode species, and its correct determination from the parasitological study of commensal rodents.

Soil-transmitted nematodes (STNs) place a tremendous burden on health and economics worldwide with an estimate of at least 1.5 billion people, or 24% of the population, being infected with at least 1 STN globally. Children and pregnant women carry the heavier pathological burden, and disease caused by the blood-feeding worm in the intestine can result in anaemia and delays in physical and intellectual development. These parasites are capable of infecting and reproducing in various host species, but what determines host specificity remains unanswered. Identifying the molecular determinants of host specificity would provide a crucial breakthrough towards understanding the biology of parasitism and could provide attractive targets for intervention. To investigate specificity mechanisms, members of the hookworm genus Ancylostoma provide a powerful system as they range from strict specialists to generalists. Using transcriptomics, differentially expressed genes (DEGs) in permissive (hamster) and non-permissive (mouse) hosts at different early time points during infection with A. ceylanicum were examined. Analysis of the data has identified unique immune responses in mice, as well as potential permissive signals in hamsters. Specifically, immune pathways associated with resistance to infection are upregulated in the non-permissive host, providing a possible protection mechanism that is absent in the permissive host. Furthermore, unique signatures of host specificity that may inform the parasite that it has invaded a permissive host were identified. These data provide novel insight into the tissue-specific gene expression differences between permissive and non-permissive hosts in response to hookworm infection.

Using morphological and molecular studies, the life cycle of Versteria cuja (Cestoda: Taeniidae) was elucidated, involving subterranean rodents (Ctenomyidae) as intermediate hosts, and the lesser grison, Galictis cuja (Mustelidae), as definitive host. Metacestodes (cysticerci and polycephalic larvae) were found mainly in the liver but also in spleen, pancreas, lungs and small intestine of 2 species of tuco-tucos (Ctenomys spp.) from Chubut, Argentina. Identity of the metacestodes with the adult was based primarily on the number, size and shape of rostellar hooks: 40–48 hooks in 2 rows, particularly small (10–16 μm total length by 6–10 μm wide), composed of handle, blade and guard with characteristic shapes. Genetic analysis (cox1 gen mtDNA) performed on metacestodes from both intermediate hosts corroborated their conspecificity with adults of V. cuja from lesser grisons in the same locality. Histopathological study showed the hepatic parenchyma altered by the presence of cysts containing larvae, each surrounded by a capsule of connective tissue with inflammatory infiltrate, atrophied hepatocytes and an increase of bile ducts. In the lung, in addition to the cysts, dilated alveoli, oedema and hyperaemic blood vessels were observed. This is the first report of a natural life cycle of a Versteria species from South America. It shows strong similarities with that described for a North American zoonotic lineage of Versteria, confirming a close relationship between V. cuja and this North American lineage, as previously demonstrated by molecular studies. Consequently, the zoonotic potential of V. cuja should not be disregarded.

Standard cages for laboratory animals are often small, minimalist and barren. Such cages can compromise animal welfare, indicating that there are welfare-based reasons for improving their designs. However, a second issue, that is, whether animals from standard laboratory housing and husbandry conditions provide valid research data, also indicates that cage designs and husbandry methods need to be improved. This paper reviews various influences of standard laboratory cage design and husbandry. These include their effects on the repeatability of studies, models of neuro-degenerative disease, sensory development, physiology, and behaviour, the effects of standard social housing and standard handling, and the effects of maternal experience on the responses of offspring. These studies show that the development and responses of animals from standard laboratory housing and husbandry conditions are often unrepresentative and idiosyncratic, indicating that data are likely to have reduced external validity. An underlying question is whether animals from standard, barren laboratory cages are ‘abnormal’ and therefore might not provide valid baseline data. In terms of animal welfare, these studies indicate that standard laboratory housing may sometimes be associated both with reduced welfare and with reduced benefits gained from research. It is suggested that in a similar manner to the use of production measures when assessing cages for production animals, laboratory cages could be assessed in terms of their suitability to provide valid research data.

The neighbouring sites of Berești and Mălușteni (Eastern Carpathian Foreland, eastern Romania) have yielded the most abundant and taxonomically diverse Pliocene vertebrate assemblages described so far from the entire country. Some of the small mammals found here were described as new taxa, and occasionally reassessed during the past one hundred years, but most of the material collected initially remained unrevised. Here, we provide a taxonomic revision of all the small mammal material (insectivores, rodents, and lagomorphs) that could be found in three main collections. The studied specimens were assigned to the insectivore families Desmanidae (Desmana verestchagini and Talpa sp.), and Erinaceidae (Erinaceus sp.); to the rodent families Muridae (Mimomys sp. or Promimomys sp.; Allocricetus sp.), Sciuridae (Spermophilus cf. nogaici), Spalacidae (Pliospalax macoveii), and Castoridae (Trogontherium minus, Castor fiber); and to the lagomorph families Leporidae (Trischizolagus dumitrescuae) and Ochotonidae (Ochotona ursui). Compared to the faunal assemblages described from Central-Eastern Europe, the identified taxa (some confirmed, others reassessed as synonyms) support an Early Pliocene age for the vertebrate assemblages from Berești and Mălușteni. Both faunal assemblages are assigned to the Ruscinian, with the faunas from Berești being considered geologically slightly older than the ones from Mălușteni.

The welfare of laboratory rats and mice is sought to be optimised through adjustment of a variety of environmental factors, including light intensity and photoperiodicity. However, the fact that rodents are able to perceive ultraviolet (UV) light tends to be ignored. The importance of being able — as a rodent — to utilise this part of the visual spectrum has not been studied in great detail, but suggestions, based on the evolutionary success of this trait, indicate that the deprivation of ultraviolet light in mice and rats could perhaps impact negatively on the welfare of these animals. Further research into the importance of having a UV light source available to rats and mice should be encouraged.

Regulation by government can act as a constraint to improving the humaneness of rodent control, or it can be used to support improvements. How do we make sure it does one and not the other? Societal support and understanding, economic impacts and current knowledge can all ‘make or break’ progress towards improved rodent control. This is also true in the development of regulations to support this improvement. Moreover, the development of regulations can itself slow progress towards better rodent control. There are many ways that governments, working in a national co-ordination role and as research funders, animal pest managers and regulators, can support a move towards improved rodent control. Progress will depend on finding ways that meet the need to control the impacts of rodents as pests and that are acceptable to citizens and budgets.

Research on the gut microbiome has gained high popularity and almost every disease has meanwhile been linked to alterations in microbiome composition. Typically assessed via stool samples, the microbiome displays a huge diversity with a multitude of environmental parameters already identified as contributing to its character. Despite impressive scientific progress, normal microbiome diversity remains largely unexplained and it is tempting to speculate some of the yet unexplained variance is hidden in normal gut physiology. Although a few genome/phenome-wide associations studies have recently highlighted physiological parameters such as stool frequency,known as contributing to microbiome diversity, there is a large knowledge base from decades of basic research on gut functions that can be explored for possible links to stool features and microbiome characteristics. And, when extrapolating findings from faecal samples to the biology in the intestinal lumen or the mucosal microenvironment, gut anatomy and physiology features need to be considered. Similarly, differences in anatomy and physiology between rodents and humans need attention when discussing findings in animals in relation to human physiology and nutrition.

Daily heterothermy is a strategy employed by endothermic birds and mammals to reduce their energetic costs by lowering their metabolic rate. We recorded nocturnal and diurnal rectal temperatures in three Moroccan Gerbillus rodent species to determine the level of heterothermy. A decrease in body temperature from night to day was observed by an average (±SD) of 8.7 (±4.2) in G. gerbillus, 11.1 (±3.0) in G. amoenus, and 7.7 (±3.3)°C in G. sp.1, the first records of heterothermy in the three species. The findings support a prediction that daily heterothermy is found in mammals from arid and semi-arid regions, contributing to further knowledge of thermoregulation in desert rodents.

Rodentolepis (sensu lato) asymmetrica (Janicki, 1904) is redescribed on the basis of materials from Microtus agrestis, Microtus arvalis and Myodes glareolus from Eastern Europe (Belarus, Lithuania, Latvia, Estonia, Ukraine and the north-eastern part of Russia). A new genus, Kontrimavichusia n. g., is proposed for it based on morphological and molecular evidence. The unique morphological diagnostic characters of this currently monotypic genus include the presence of an armature on the suckers, ventral osmoregulatory canals connected with irregularly spaced transverse anastomoses, an internal seminal vesicle with circular musculature and uterus with numerous diverticula, situated dorsally to the genital ducts, extending bilaterally beyond the longitudinal osmoregulatory canals. In addition, the new genus differs from morphologically related genera of the Rodentolepis clade by the structure of its vagina. The copulatory part of the vagina in specimens of Kontrimavichusia n. g. is surrounded by circular musculature and covered externally by a dense layer of intensely-stained cells; the conductive part of the vagina is clearly distinguishable from the seminal receptacle. Molecular analysis of the partial 28S rRNA gene fully supports the erection of Kontrimavichusia n. g. as a distinct lineage.

The mdx mouse is an experimental model of Duchenne muscular dystrophy, a genetic disorder characterized by progressive muscular degeneration which affects the oral cavity musculature, and promotes difficulty in swallowing. This study aimed to describe morphological, structural, and ultrastructural changes in the tongue mucosa and musculature of mdx mice. Forty six-month-old mice were divided into two groups: Control C57bl/10 (n = 20) and mdx C57bl/10mdx (n = 20). The tongue was dissected and analyzed with light microscopy, scanning electron microscopy, and transmission electron microscopy techniques. Our results showed conical and triangular filiform, fungiform, foliate, and vallate papillae, and their connective tissue cores. The epithelium layers identified were corneum, granulosum, spinosum, and basale. The mdx group had a thicker epithelium. Lamina propria was composed of reddish and greenish collagen. In mdx, collagen was present in the musculature of the tongue's body and in the muscular tissue between mucous and serous glands of the caudal region. Musculature was also characterized by a shorter length of sarcoplasmic invaginations, myocytolysis in mitochondrial groupings, and inflammatory focus. In conclusion, the tongue of 6-month-old mdx mice had morphology, structure, and ultrastructure revealed, showing higher wear of filiform papillae indirect reflex from the muscular degeneration process.

Urban rodents are associated with parasites and pathogens, which present health risks for humans, but information on factors related to parasite and pathogen infection in rodents in cities of Latin America is scarce. This study analyzes the hosts, host community structure and environmental characteristics of parasite and pathogen fauna present in the three species of urban rodents in an urban area of South America. Rodents were captured seasonally in seven different neighborhoods. Digestive tracts were dissected under stereoscopic microscopy and feces were processed using a sedimentation technique. Protozoa and bacteria were detected through polymerase chain reaction and indirect immunofluorescence techniques. In Rattus norvegicus, Rattus rattus and Mus musculus, ten helminths, three protozoa and two bacteria were found. Six were zoonotic: Toxoplasma gondii; Hymenolepis diminuta; Rodentolepis nana; Strobilocercus fasciolaris; Leptospira borgpetersenii; and Leptospira interrogans. The parasite and pathogen infections were influenced by the host species, the host community structure, the season, and the presence of streams in the neighborhood. Urban rodents may be the infection source of many zoonotic diseases and it is important to generate public policies for this problem. This study is one example of the situation of many cities of Latin America, where peripheral neighborhoods are growing dramatically.

Epidemiologically, metabolic disorders have garnered much attention, perhaps due to the predominance of obesity. The early postnatal life represents a critical period for programming multifactorial metabolic disorders of adult life. Though altricial rodents are prime subjects for investigating neonatal programming, there is still no sufficiently generalised literature on their usage and methodology. This review focuses on establishing five approach-based models of neonatal rodents adopted for studying metabolic phenotypes. Here, some modelled interventions that currently exist to avoid or prevent metabolic disorders are also highlighted. We also bring forth recommendations, guidelines and considerations to aid research on neonatal programming. It is hoped that this provides a background to researchers focused on the aetiology, mechanisms, prevention and treatment of metabolic disorders.

Understanding the role of species traits in mediating ecological interactions and shaping community structure is a key question in ecology. In this sense, parasite population parameters allow us to estimate the functional importance of traits in shaping the strength of interactions among hosts and parasites in a network. The aim of this study was to survey and analyse the small mammal-helminth network in a forest reserve of the Brazilian Atlantic Forest in order to understand (i) how functional traits (type of parasite life cycle, site of infection in their host, host and parasite body length, host diet, host locomotor habit and host activity period) and abundance influence host–parasite interactions, (ii) whether these traits explain species roles, and (iii) if this relationship is consistent across different parasite population parameters (presence and absence, mean abundance and prevalence). Networks were modular and their structural patterns did not vary among the population parameters. Functional traits and abundance shaped the interactions observed between parasites and hosts. Host species abundance, host diet and locomotor habit affected their centrality and/or vulnerability to parasites. For helminths, infection niche was the main trait determining their central roles in the networks.

The aim of the study is to test a hypothesis for the phylogenetic relationships among mammalian hymenolepidid tapeworms, based on partial (D1–D3) nuclear 28S ribosomal RNA (rRNA) genes, by estimating new molecular phylogenies for the group based on partial mitochondrial cytochrome c oxidase I (COI) and nuclear 18S rRNA genes, as well as a combined analysis using all three genes. New sequences of COI and 18S rRNA genes were obtained for Coronacanthus integrus, C. magnihamatus, C. omissus, C. vassilevi, Ditestolepis diaphana, Lineolepis scutigera, Spasskylepis ovaluteri, Staphylocystis tiara, S. furcata, S. uncinata, Vaucherilepis trichophorus and Neoskrjabinolepis sp. The phylogenetic analyses confirmed the major clades identified by Haukisalmi et al. (Zoologica Scripta 39: 631–641, 2010): Ditestolepis clade, Hymenolepis clade, Rodentolepis clade and Arostrilepis clade. While the Ditestolepis clade is associated with soricids, the structure of the other three clades suggests multiple evolutionary events of host switching between shrews and rodents. Two of the present analyses (18S rRNA and COI genes) show that the basal relationships of the four mammalian clades are branching at the same polytomy with several hymenolepidids from birds (both terrestrial and aquatic). This may indicate a rapid radiation of the group, with multiple events of colonizations of mammalian hosts by avian parasites.

Jackfruit (Artocarpus heterophyllus Lam.) is an exotic invasive plant species in the Brazilian Atlantic Forest that causes changes in the environment through the release of allelopathic substances and has high fruit production. We aimed to understand the potential effects of the jackfruit on the non-volant small mammal assemblage in an area protected by law, in the municipality of Cariacica – Espírito Santo, south-eastern Brazil. We sampled the small mammals assemblage using live traps in 18 sites, eight with jackfruit and 10 without. We ordinated the assemblage and tested possible differences in species richness and abundance according to the jackfruit density. We recorded 31 species of non-volant small mammals, with 13 species endemic to the Atlantic Forest. Jackfruit species can affect both positively and negatively the studied assemblage of non-volant small mammals. For species with a frugivory habit, jackfruit has a positive effect favouring these species. On the other hand, for insectivorous species, jackfruit represents an impact inhibiting the presence of these species in an area with high jackfruit density. The results presented are the first step in understanding the effect of this invasive species on a small mammals assemblage and initiating a monitoring of these species in areas affected by jackfruits. Furthermore, management of jackfruits in this protected area is required.

Resource depression and garden hunting are major topics of archaeological interest, with important implications for understanding cultural and environmental change. Garden hunting is difficult to study using traditional zooarchaeological approaches, but isotopic analyses of animals may provide a marker for where and when people exploited nondomesticated animals that fed on agricultural resources. To realize the full potential of isotopic approaches for reconstructing garden hunting practices—and the impacts of agriculture on past nondomesticated animal populations more broadly—a wider range of species, encompassing many “ecological perspectives,” is needed. We use bone-collagen isotopic compositions of animals (n = 643, 23 taxa, 39 sites) associated with the Late Woodland (~AD 900−1650) in what is now southern Ontario to test hypotheses about the extent to which animals used maize, an isotopically distinctive plant central to subsistence practices of Iroquoian-speaking peoples across the region. Results show that although some taxa—particularly those that may have been hard to control—had substantial access to maize, most did not, regardless of the animal resource requirements of local populations. Our findings suggest that this isotopic approach to detecting garden hunting will be more successful when applied to smaller-scale societies.

Chigger mites (Trombiculidae) are temporary habitat-specific ectoparasites that often occur on rodents. Little ecological data are available on chiggers associated with rodents in South Africa. The study aims were to (1) record the chigger species associated with rodents in the savanna, (2) assess if chigger species display parasitope preference on the rodent body and (3) compare the distribution of chigger species in natural, agricultural and urban habitats. Rodents (n = 314) belonging to eight genera were trapped in the savanna biome during 2014 and 2015. Twelve chigger species, of which five are recently described species, were recorded from 161 rodent hosts. The data include three new country locality records. Microtrombicula mastomyia was the most prevalent species across sampling seasons and habitat types. Significant parasitope preference was recorded for two species, with the ear, face and tail base some of the preferred attachment sites. Sampling season and habitat type had a significant effect on chigger communities with summer and agricultural habitats recording the highest species richness, while the highest species diversity was recorded in natural habitats. The study contributes to our current knowledge regarding rodent-associated chigger diversity and distribution in South Africa and further highlights the importance of environmental characteristics in shaping chigger communities.