Ancient Mycobacterium leprae genome reveals medieval English red squirrels as animal leprosy host.

Leprosy, one of the oldest recorded diseases in human history, remains prevalent in Asia, Africa, and South America, with over 200,000 cases every year.1,2 Although ancient DNA (aDNA) approaches on the major causative agent, Mycobacterium leprae, have elucidated the disease's evolutionary history,3,4,5 the role of animal hosts and interspecies transmission in the past remains unexplored. Research has uncovered relationships between medieval strains isolated from archaeological human remains and modern animal hosts such as the red squirrel in England.6,7 However, the time frame, distribution, and direction of transmissions remains unknown. Here, we studied 25 human and 12 squirrel samples from two archaeological sites in Winchester, a medieval English city well known for its leprosarium and connections to the fur trade. We reconstructed four medieval M. leprae genomes, including one from a red squirrel, at a 2.2-fold average coverage. Our analysis revealed a phylogenetic placement of all strains on branch 3 as well as a close relationship between the squirrel strain and one newly reconstructed medieval human strain. In particular, the medieval squirrel strain is more closely related to some medieval human strains from Winchester than to modern red squirrel strains from England, indicating a yet-undetected circulation of M. leprae in non-human hosts in the Middle Ages. Our study represents the first One Health approach for M. leprae in archaeology, which is centered around a medieval animal host strain, and highlights the future capability of such approaches to understand the disease's zoonotic past and current potential.

Chemically induced cone degeneration in the 13-lined ground squirrel.

Animal models of retinal degeneration are critical for understanding disease and testing potential therapies. Inducing degeneration commonly involves the administration of chemicals that kill photoreceptors by disrupting metabolic pathways, signaling pathways, or protein synthesis. While chemically induced degeneration has been demonstrated in a variety of animals (mice, rats, rabbits, felines, 13-lined ground squirrels (13-LGS), pigs, chicks), few studies have used noninvasive high-resolution retinal imaging to monitor the in vivo cellular effects. Here, we used longitudinal scanning light ophthalmoscopy (SLO), optical coherence tomography, and adaptive optics SLO imaging in the euthermic, cone-dominant 13-LGS (46 animals, 52 eyes) to examine retinal structure following intravitreal injections of chemicals, which were previously shown to induce photoreceptor degeneration, throughout the active season of 2019 and 2020. We found that iodoacetic acid induced severe pan-retinal damage in all but one eye, which received the lowest concentration. While sodium nitroprusside successfully induced degeneration of the outer retinal layers, the results were variable, and damage was also observed in 50% of contralateral control eyes. Adenosine triphosphate and tunicamycin induced outer retinal specific damage with varying results, while eyes injected with thapsigargin did not show signs of degeneration. Given the variability of damage we observed, follow-up studies examining the possible physiological origins of this variability are critical. These additional studies should further advance the utility of chemically induced photoreceptor degeneration models in the cone-dominant 13-LGS.

Uptown Squirrel Does Not Eat That.

This essay plays out a few ethics reasons we have to reconsider what's really being marketed to us in some free offers that distract us from questions of ethical, cultural, and clinical importance, for example. Possible points of focus for bioethics as a field are related to antimicrobial resistance and stewardship.

Long-term, medium-term and acute stress response of urban populations of Eurasian red squirrels affected by different levels of human disturbance.

Animals in urban areas often encounter novel and potentially stressful conditions. It is important to understand how wildlife cope with anthropogenic disturbance. To investigate this specific adaptation we live-trapped squirrels in two study sites in Warsaw: a forest reserve and an urban park and we estimated stress responses at three levels: long-term and medium-term stress (the level of stress hormones, i.e. cortisol and cortisone concentrations, in hair and feces) and acute reaction to human-induced stress (measured during handling with the aid of the three indices: breath rate, struggle rate, and vocalization). According to GLMM models no difference in the stress hormones level was found between the two populations. The only differences in cortisol concentrations clearly depended on the season, i.e. being higher in autumn and winter comparying to other seasons. There was no influence of sex, or reproductive status on stress hormones. Forest squirrels had significantly higher breath rates, suggesting they were more stressed by handling. There was no difference in the struggle rate between study areas, this index was mostly affected by season (i.e. being highest in winter). First-trapped squirrels vocalized less than during the subsequent trappings. Assumingly, during the first, and more stressful trapping, squirrels used 'freezing' and/or little vocalization, while during next captures they used alarm calls to warn conspecifics. Overall, we showed that the two squirrel populations differed only in terms of their breath rate. This suggests that they did not differ in medium-term and long-term stress in general, but they can differ in acute response to handling. This also suggests that both populations were similarly affected by environmental factors. The lack of clear effects may also be due to population heterogeneity. Thus, in order to assess the effects of anthropogenic stressors a broader range of indicators and diverse analytical methods, including behavioral analyses, should be employed.

Hit Snooze: An Imperiled Hibernator Assesses Spring Snow Conditions to Decide Whether to Terminate Hibernation or Reenter Torpor.

AbstractMany animals follow annual cycles wherein physiology and behavior change seasonally. Hibernating mammals undergo one of the most drastic seasonal alterations of physiology and behavior, the timing of which can have significant fitness consequences. The environmental cues regulating these profound phenotypic changes will heavily influence whether hibernators acclimate and ultimately adapt to climate change. Hence, identifying the cues and proximate mechanisms responsible for hibernation termination timing is critical. Northern Idaho ground squirrels (Urocitellus brunneus)-a rare, endemic species threatened with extinction-exhibit substantial variation in hibernation termination phenology, but it is unclear what causes this variation. We attached geolocators to free-ranging squirrels to test the hypothesis that squirrels assess surface conditions in spring before deciding whether to terminate seasonal heterothermy or reenter torpor. Northern Idaho ground squirrels frequently reentered torpor following a brief initial emergence from hibernacula and were more likely to do so earlier in spring or when challenged by residual snowpack. Female squirrels reentered torpor when confronted with relatively shallow snowpack upon emergence, whereas male squirrels reentered torpor in response to deeper spring snowpack. This novel behavior was previously assumed to be physiologically constrained in male ground squirrels by testosterone production required for spermatogenesis and activated by the circannual clock. Assessing surface conditions to decide when to terminate hibernation may help buffer these threatened squirrels against climate change. Documenting the extent to which other hibernators can facultatively alter emergence timing by reentering torpor after emergence will help identify which species are most likely to persist under climate change.

Exploring Alashan Ground Squirrel (Spermophilus alashanicus) Diversity: Metagenomic and Transcriptomic Datasets from the Helan Mountains.

This study investigates the adaptive strategies of the Alashan Ground Squirrel (Spermophilus alashanicus) in response to habitat changes, as rodents are sensitive indicators of ecosystem changes. Despite its ecological importance, the genome and microbiome of this species have not been thoroughly studied. This research fills this gap by presenting the first comprehensive metagenomic and transcriptomic datasets of the species. Transcriptomic data was collected from five tissue types, including heart, liver, cecum, muscle, and blood, resulting in the assembly of 72,156 unigenes. Metagenomic sequencing identified predominant bacterial groups such as Firmicutes, Bacteroidetes, Verrucomicrobia, Urovircota, and Proteobacteria. Our workflow involved RNA and DNA extraction, library preparation, assembly, and annotation, yielding valuable insights into gene discovery, microbial composition, and further genome and microbial function studies. In conclusion, our findings have significant implications for understanding the adaptive mechanisms of this species in response to environmental changes.

An effective hotspot mitigation system for Wireless Sensor Networks using hybridized prairie dog with Genetic Algorithm.

Wireless Sensor Networks (WSNs) consist of small, multifunctional nodes distributed across various locations to monitor and record parameters. These nodes store data and transmit signals for further processing, forming a crucial topic of study. Monitoring the network's status in WSN applications using clustering systems is essential. Collaboration among sensors from various domains enhances the precision of localised information reporting. However, nodes closer to the data sink consume more energy, leading to hotspot challenges. To address these challenges, this research employs clustering and optimised routing techniques. The aggregation of information involves creating clusters, further divided into sub-clusters. Each cluster includes a Cluster Head (CH) or Sensor Nodes (SN) without a CH. Clustering inherently optimises CHs' capabilities, enhances network activity, and establishes a systematic network topology. This model accommodates both multi-hop and single-hop systems. This research focuses on selecting CHs using a Genetic Algorithm (GA), considering various factors. While GA possesses strong exploration capabilities, it requires effective management. This research uses Prairie Dog Optimization (PDO) to overcome this challenge. The proposed Hotspot Mitigated Prairie with Genetic Algorithm (HM-PGA) significantly improves WSN performance, particularly in hotspot avoidance. With HM-PGA, it achieves a network lifetime of 20913 milliseconds and 310 joules of remaining energy. Comparative analysis with existing techniques demonstrates the superiority of the proposed approach.

A future food boom rescues the negative effects of early-life adversity on adult lifespan in a small mammal.

Early-life adversity, even when transient, can have lasting effects on individual phenotypes and reduce lifespan across species. If these effects can be mitigated by a high-quality later-life environment, then differences in future resources may explain variable resilience to early-life adversity. Using data from over 1000 wild North American red squirrels, we tested the hypothesis that the costs of early-life adversity for adult lifespan could be offset by later-life food abundance. We identified six adversities that reduced juvenile survival in the first year of life, though only one-birth date-had continued independent effects on adult lifespan. We then built a weighted early-life adversity (wELA) index integrating the sum of adversities and their effect sizes. Greater weighted early-life adversity predicted shorter adult lifespans in males and females, but a naturally occurring food boom in the second year of life ameliorated this effect. Experimental food supplementation did not replicate this pattern, despite increasing lifespan, indicating that the buffering effect of a future food boom may hinge on more than an increase in available calories. Our results suggest a non-deterministic role of early-life conditions for later-life phenotype, highlighting the importance of evaluating the consequences of early-life adversity in the context of an animal's entire life course.

Paper towel shredding as a novel, affordable, noninvasive method for detecting arousals in hibernating rodents.

Many research groups explore the regulation of hibernation or compare the physiology of heterothermic mammals between the torpid and aroused, euthermic states. Current methods for monitoring torpor (for example, infrared cameras, body temperature or heart-rate telemetry, and motion sensing) are costly, require specialized techniques, and can be invasive. Here we present an alternate method for determining torpor-bout duration that is cost-effective, noninvasive and accurate: paper towel shredding. In the winter, euthermic thirteen-lined ground squirrels will shred paper towels placed in the cage, but torpid animals will not. The presence of a shredded paper towel, indicating an arousal from torpor, is easily evaluated during routine daily monitoring. In 12 animals over 52 days, this simple technique detected 59 arousals with 100% accuracy when compared with the body temperature telemetry of the same animals. Moreover, this novel method avoids some of the drawbacks of other cheap monitoring systems such as the sawdust technique.

Range of Ixodes laguri, a nidicolous tick that parasitizes critically endangered rodents, with details on its western distribution limit in Austria.

The nidicolous tick Ixodes laguri is a nest-dwelling parasite of small mammals that mainly infest rodents of the families Cricetidae, Gliridae, Muridae and Sciuridae. There is no proven vectorial role for I. laguri, although it is suggested that it is a vector of Francisella tularensis. In this study, a first map depicting the entire geographical distribution of I. laguri based on georeferenced locations is presented. For this purpose, a digital data set of 142 georeferenced locations from 16 countries was compiled. Particular attention is paid to the description of the westernmost record of I. laguri in the city of Vienna, Austria. There, I. laguri is specifically associated with its main hosts, the critically endangered European hamster (Cricetus cricetus) and the European ground squirrel (Spermophilus citellus). These two host species have also been mapped in the present paper to estimate the potential distribution of I. laguri in the Vienna metropolitan region. The range of I. laguri extends between 16-108∘ E and 38-54∘ N, i.e. from Vienna in the east of Austria to Ulaanbaatar, the capital of Mongolia. In contrast to tick species that are expanding their range and are also becoming more abundant as a result of global warming, I. laguri has become increasingly rare throughout its range. However, I. laguri is not threatened by climate change, but by anthropogenic influences on its hosts and their habitats, which are typically open grasslands and steppes. Rural habitats are threatened by the intensification of agriculture and semi-urban habitats are increasingly being destroyed by urban development.

Intestinal parasites of the endangered European ground squirrel (Spermophilus citellus) populations in Slovakia.

The present pilot research was focused on the detection of intestinal parasites in the ground squirrel populations in various regions of Slovakia. Only a very little information is currently available on the parasitic species composition of the European ground squirrel in Slovakia and across Europe. In the Slovak Republic, there are 70 locations where the ground squirrel populations are present. A total of 600 faecal samples of the European ground squirrels, collected from 36 locations all over Slovakia, were examined by applying the coprological method. The presence of the protozoan coccidian parasite of the Eimeria genus was confirmed in all of the analysed locations. The presence of eggs of four helminths were confirmed: Capillaria spp. (66.6% of locations); the Trichostrongylidae family (42.8% of locations); Hymenolepis spp. (11.9% of locations); and Citellina spp. (7.14% of locations). Dead individuals that were found in the analysed localities were subjected to necropsy and the tissues scraped off their small intestines were stained in order to confirm the presence of parasites. The post-mortem examination of the intestines and the sedimentation of the intestinal contents in a saline solution did not result in the confirmation of the presence of the eggs, adults or the larval stages of parasites. Spermophilus citellus is one of the strictly protected animal species in Slovakia. In recent years, numerous projects aimed at supporting and protecting ground squirrels have been implemented. The present pilot study on intestinal parasites and the subsequent cooperation with environmental activists will contribute to the support and stabilisation of the presence of these animals in our country.

Complex effects of testosterone level on ectoparasite load in a ground squirrel: an experimental test for the immunocompetence handicap hypothesis.

BACKGROUND: The immunocompetence handicap hypothesis suggests that males with a higher testosterone level should be better at developing male secondary traits, but at a cost of suppressed immune performance. As a result, we should expect that males with an increased testosterone level also possess a higher parasite load. However, previous empirical studies aimed to test this prediction have generated mixed results. Meanwhile, the effect of testosterone level on parasite load in female hosts remains poorly known. METHODS: In this study, we tested this prediction by manipulating testosterone level in Daurian ground squirrels (Spermophilus dauricus), a medium-sized rodent widely distributed in northeast Asia. S. dauricus is an important host of ticks and fleas and often viewed as a considerable reservoir of plague. Live-trapped S. dauricus were injected with either tea oil (control group) or testosterone (treatment group) and then released. A total of 10 days later, the rodents were recaptured and checked for ectoparasites. Fecal samples were also collected to measure testosterone level of each individual. RESULTS: We found that testosterone manipulation and sex of hosts interacted to affect tick load. At the end of the experiment, male squirrels subjected to testosterone implantation had an averagely higher tick load than males from the control group. However, this pattern was not found in females. Moreover, testosterone manipulation did not significantly affect flea load in S. dauricus. CONCLUSIONS: Our results only lent limited support for the immunocompetence handicap hypothesis, suggesting that the role of testosterone on regulating parasite load is relatively complex, and may largely depend on parasite type and gender of hosts.

Traditional multilocus phylogeny fails to fully resolve Palearctic ground squirrels (Spermophilus) relationships but reveals a new species endemic to West Siberia.

Previous efforts to reconstruct evolutionary history of Palearctic ground squirrels within the genus Spermophilus have primarily relied on a single mitochondrial marker for phylogenetic data. In this study, we present the first phylogeny with comprehensive taxon sampling of Spermophilus via a conventional multilocus approach utilizing five mitochondrial and five nuclear markers. Through application of the multispecies coalescent model, we constructed a species tree revealing four distinct clades that diverged during the Late Miocene. These clades are 1) S. alaschanicus and S. dauricus from East Asia; 2) S. musicus and S. pygmaeus from East Europe and northwestern Central Asia; 3) the subgenus Colobotis found across Central Asia and its adjacent regions and encompassing S. brevicauda, S. erythrogenys, S. fulvus, S. major, S. pallidicauda, S. ralli, S. relictus, S. selevini, and S. vorontsovi sp. nov.; and 4) a Central/Eastern Europe and Asia Minor clade comprising S. citellus, S. taurensis, S. xanthoprymnus, S. suslicus, and S. odessanus. The latter clade lacked strong support owing to uncertainty of taxonomic placement of S. odessanus and S. suslicus. Resolving relationships within the subgenus Colobotis, which radiated rapidly, remains challenging likely because of incomplete lineage sorting and introgressive hybridization. Most of modern Spermophilus species diversified during the Early-Middle Pleistocene (2.2-1.0 million years ago). We propose a revised taxonomic classification for the genus Spermophilus by recognizing 18 species including a newly identified one (S. vorontsovi sp. nov.), which is found only in a limited area in the southeast of West Siberia. Employing genome-wide single-nucleotide polymorphism genotyping, we substantiated the role of the Ob River as a major barrier ensuring robust isolation of this taxon from S. erythrogenys. Despite its inherent limitations, the traditional multilocus approach remains a valuable tool for resolving relationships and can provide important insights into otherwise poorly understood groups. It is imperative to recognize that additional efforts are needed to definitively determine phylogenetic relationships between certain species of Palearctic ground squirrels.

Plasticity changes in iron homeostasis in hibernating Daurian ground squirrels (Spermophilus dauricus) may counteract chronically inactive skeletal muscle atrophy.

Disuse-induced muscular atrophy is frequently accompanied by iron overload. Hibernating animals are a natural animal model for resistance to disuse muscle atrophy. In this paper, we explored changes in skeletal muscle iron content of Daurian ground squirrels (Spermophilus dauricus) during different periods of hibernation as well as the regulatory mechanisms involved. The results revealed that compared with the summer active group (SA), iron content in the soleus muscle (SOL) decreased (- 65%) in the torpor group (TOR), but returned to normal levels in the inter-bout arousal (IBA); splenic iron content increased in the TOR group (vs. SA, + 67%), decreased in the IBA group (vs. TOR, - 37%). Expression of serum hepcidin decreased in the TOR group (vs. SA, - 22%) and returned to normal levels in the IBA groups; serum ferritin increased in the TOR group (vs. SA, + 31%), then recovered in the IBA groups. Soleus muscle transferrin receptor 1 (TfR1) expression increased in the TOR group (vs. SA, + 83%), decreased in the IBA group (vs. TOR, - 30%); ferroportin 1 increased in the IBA group (vs. SA, + 55%); ferritin increased in the IBA group (vs. SA, + 42%). No significant differences in extensor digitorum longus in iron content or iron metabolism-related protein expression were observed among the groups. Significantly, all increased or decreased indicators in this study returned to normal levels after the post-hibernation group, showing remarkable plasticity. In summary, avoiding iron overload may be a potential mechanism for hibernating Daurian ground squirrels to avoid disuse induced muscular atrophy. In addition, the different skeletal muscle types exhibited unique strategies for regulating iron homeostasis.

With super SDMs (machine learning, open access big data, and the cloud) towards more holistic global squirrel hotspots and coldspots.

Species-habitat associations are correlative, can be quantified, and used for powerful inference. Nowadays, Species Distribution Models (SDMs) play a big role, e.g. using Machine Learning and AI algorithms, but their best-available technical opportunities remain still not used for their potential e.g. in the policy sector. Here we present Super SDMs that invoke ML, OA Big Data, and the Cloud with a workflow for the best-possible inference for the 300 + global squirrel species. Such global Big Data models are especially important for the many marginalized squirrel species and the high number of endangered and data-deficient species in the world, specifically in tropical regions. While our work shows common issues with SDMs and the maxent algorithm ('Shallow Learning'), here we present a multi-species Big Data SDM template for subsequent ensemble models and generic progress to tackle global species hotspot and coldspot assessments for a more inclusive and holistic inference.

Sulfide catabolism in hibernation and neuroprotection.

The mammalian brain is exquisitely vulnerable to lack of oxygen. However, the mechanism underlying the brain's sensitivity to hypoxia is incompletely understood. In this narrative review, we present a case for sulfide catabolism as a key defense mechanism of the brain against acute oxygen shortage. We will examine literature on the role of sulfide in hypoxia/ischemia, deep hibernation, and leigh syndrome patients, and present our recent data that support the neuroprotective effects of sulfide catabolism and persulfide production. When oxygen levels become low, hydrogen sulfide (H2S) accumulates in brain cells and impairs the ability of these cells to use the remaining, available oxygen to produce energy. In recent studies, we found that hibernating ground squirrels, which can withstand very low levels of oxygen, have high levels of sulfide:quinone oxidoreductase (SQOR) and the capacity to catabolize hydrogen sulfide in the brain. Silencing SQOR increased the sensitivity of the brain of squirrels and mice to hypoxia, whereas neuron-specific SQOR expression prevented hypoxia-induced sulfide accumulation, bioenergetic failure, and ischemic brain injury in mice. Excluding SQOR from mitochondria increased sensitivity to hypoxia not only in the brain but also in heart and liver. Pharmacological agents that scavenge sulfide and/or increase persulfide maintained mitochondrial respiration in hypoxic neurons and made mice resistant to ischemic injury to the brain or spinal cord. Drugs that oxidize hydrogen sulfide and/or increase persulfide may prove to be an effective approach to the treatment of patients experiencing brain injury caused by oxygen deprivation or mitochondrial dysfunction.

CHARACTERIZATION OF EIMERIA LANCASTERENSIS AND EIMERIA ONTARIOENSIS (APICOMPLEXA: EIMERIIDAE) FOUND IN EASTERN GRAY SQUIRRELS, SCIURUS CAROLINENSIS (RODENTIA: SCIURIDAE), FROM ARKANSAS AND OKLAHOMA.

We report the morphological characteristics of oocysts of Eimeria lancasterensisJoseph, 1969, collected from 6 of 6 (100%) eastern gray squirrels, Sciurus carolinensis, collected in Arkansas (n = 3) and Oklahoma (n = 3), and Eimeria ontarioensisLee and Dorney, 1971, recovered from an individual of S. carolinensis from Arkansas. Oocysts of E. lancasterensis were ovoidal to ellipsoidal, measuring (L × W) 24.0 × 14.6 (18-29 × 12-16) µm; shape index (L/W) was 1.6 (1.3-1.8). A micropyle and an oocyst residuum were absent, but up to 2 polar granules were present. Oocysts of E. ontarioensis were piriform and measured 40.6 × 26.0 (37-44 × 23-28); L/W was 1.6 (1.5-1.7). These oocysts possessed a distinct micropyle and rarely a polar granule but lacked an oocyst residuum. The DNA was isolated from both eimerians, and the 18S rDNA genetic markers were PCR-amplified, cloned, sequenced, and analyzed. To our knowledge, this study represents the first time 18S DNA sequence data have been generated from E. lancasterensis and E. ontarioensis found in North American sciurid hosts, as well as new geographic distribution records for these coccidians. In addition, we also include a tabular summary of these 2 species of Eimeria from Sciurus spp. worldwide, with information on their hosts, distribution, and taxonomically important morphological characteristics, including key measurements of oocysts and sporocysts.

A cyst-forming coccidian with large geographical range infecting forest and commensal rodents: Sarcocystis muricoelognathis sp. nov.

BACKGROUND: The geographic distribution and host-parasite interaction networks of Sarcocystis spp. in small mammals in eastern Asia remain incompletely known. METHODS: Experimental infections, morphological and molecular characterizations were used for discrimination of a new Sarcocystis species isolated from colubrid snakes and small mammals collected in Thailand, Borneo and China. RESULTS: We identified a new species, Sarcocystis muricoelognathis sp. nov., that features a relatively wide geographic distribution and infects both commensal and forest-inhabiting intermediate hosts. Sarcocystis sporocysts collected from rat snakes (Coelognathus radiatus, C. flavolineatus) in Thailand induced development of sarcocysts in experimental SD rats showing a type 10a cyst wall ultrastructure that was identical with those found in Rattus norvegicus from China and the forest rat Maxomys whiteheadi in Borneo. Its cystozoites had equal sizes in all intermediate hosts and locations, while sporocysts and cystozoites were distinct from other Sarcocystis species. Partial 28S rRNA sequences of S. muricoelognathis from M. whiteheadi were largely identical to those from R. norvegicus in China but distinct from newly sequenced Sarcocystis zuoi. The phylogeny of the nuclear 18S rRNA gene placed S. muricoelognathis within the so-called S. zuoi complex, including Sarcocystis attenuati, S. kani, S. scandentiborneensis and S. zuoi, while the latter clustered with the new species. However, the phylogeny of the ITS1-region confirmed the distinction between S. muricoelognathis and S. zuoi. Moreover, all three gene trees suggested that an isolate previously addressed as S. zuoi from Thailand (KU341120) is conspecific with S. muricoelognathis. Partial mitochondrial cox1 sequences of S. muricoelognathis were almost identical with those from other members of the group suggesting a shared, recent ancestry. Additionally, we isolated two partial 28S rRNA Sarcocystis sequences from Low's squirrel Sundasciurus lowii that clustered with those of S. scandentiborneensis from treeshews. CONCLUSIONS: Our results provide strong evidence of broad geographic distributions of rodent-associated Sarcocystis and host shifts between commensal and forest small mammal species, even if the known host associations remain likely only snapshots of the true associations.

A new genus and new species of sucking louse (Phthiraptera: Anoplura: Enderleinellidae) from the particoloured flying squirrel (Hylopetes alboniger) in Laos, and an updated identification key to enderleinellid genera.

Hylophthirus spinosus, new genus and new species (Phthiraptera: Anoplura: Enderleinellidae), is described from specimens collected from the particoloured flying squirrel, Hylopetes alboniger in Khammouane Province, Laos (Lao Peoples Democratic Republic). Both sexes of the new louse are illustrated with stacked microphotographs, scanning electron micrographs and line drawings. An updated morphological identification key to the six genera (Atopophthirus, Enderleinellus, Hylophthirus, Microphthirus, Phthirunculus and Werneckia) now recognised within the family Enderleinellidae is presented. The new genus is unique within the Enderleinellidae in having massive spines (modified setae) on some abdominal sternites, partially bulbous 5th antennal segments, mesothoracic spiracles borne on protuberances and the morphology of the genitalia of both sexes. Tables showing all genera of sucking lice that include species parasitising sciurids (squirrels, chipmunks, susliks and marmots), and all known species of enderleinellids, with their known host associations and geographical distributions are included and briefly discussed in relation to the new genus and species.