Free-living Mammals Research Articles

Host traits, identity, and ecological conditions predict consistent flea abundance and prevalence on free-living California ground squirrels

Understanding why some individuals are more prone to carry parasites and spread diseases than others is a key question in biology. Although epidemiologists and disease ecologists increasingly recognize that individuals of the same species can vary tremendously in their relative contributions to the emergence of diseases, very few empirical studies systematically assess consistent individual differences in parasite loads within populations over time. Two species of fleas (Oropsylla montana and Hoplopsyllus anomalous) and their hosts, California ground squirrels (Otospermophilus beecheyi), form a major complex for amplifying epizootic plague in the western United States. Understanding its biology is primarily of major ecological importance and is also relevant to public health. Here, we capitalize on a long-term data set to explain flea incidence on California ground squirrels at Briones Regional Park in Contra Costa County, USA. In a 7 year study, we detected 42,358 fleas from 2,759 live trapping events involving 803 unique squirrels from two free-living populations that differed in the amount of human disturbance in those areas. In general, fleas were most abundant and prevalent on adult males, on heavy squirrels, and at the pristine site, but flea distributions varied among years, with seasonal conditions (e.g., temperature, rainfall, humidity), temporally within summers, and between flea species. Although on-host abundances of the two flea species were positively correlated, each flea species occupied a distinctive ecological niche. The common flea (O. montana) occurred primarily on adults in cool, moist conditions in early summer whereas the rare flea (H. anomalous) was mainly on juveniles in hot, dry conditions in late summer. Beyond this, we uncovered significantly repeatable and persistent effects of host individual identity on flea loads, finding consistent individual differences among hosts in all parasite measures. Taken together, we reveal multiple determinants of parasites on free-living mammals, including the underappreciated potential for host heterogeneity – within populations – to structure the emergence of zoonotic diseases such as bubonic plague.

Эпизоотологический мониторинг лептоспироза лошадей в Омской области

Leptospirosis is one of the urgent problems of veterinary medicine and causes significant material damage to livestock, threatening human health and life. The paper presents the results of a study of the epizootic situation of the manifestation of leptospirosis among horses in the Omsk region for the period 2016-2020 and identifies unfavorable points for this disease. It was found that areas unfavorable for leptospirosis are mainly located in the forest-steppe zone of the Omsk region (Maryanovsky, Azovsky, Omsk, Moskalensky, Tyukalinsky, Is-ilkulsky, Lyubinsky, Kormilovsky) or on the border with the steppe zone (Tavrichesky and Azov). For the development of an epizootic of leptospirosis, there are pronounced prerequisites in the form of various reservoirs and free-living small mammals. The most intense epizootic situation is in the Maryanovsky district, where leptospirosis in horses is annually recorded.

Post mortem protozoan hemoparasites detection in wild mammals from Mato Grosso state, Midwestern Brazil.

To a better insight into the epidemiology and genetic diversity of protozoan hemoparasites infections in wild mammals, this study aimed to the post mortem detection of DNA from species of the order Piroplasmida (Babesia sp., Cytauxzoon sp., and Theileria sp.) and suborder Adelorina (Hepatozoon sp.) using polymerase chain reaction based on the 18S rRNA gene followed by genetic sequencing of blood and spleen samples collected from carcasses of 164 free-ranging and captive wild mammals from Mato Grosso state. Among them, one Leopardus pardalis, three Panthera onca, two Puma concolor were positive for Cytauxzoon sp., and six Tapirus terrestris tested positive for Piroplasmida, while one L. pardalis was positive for Hepatozoon sp. Furthermore, an uncharacterized piroplasmid genetically related to Theileria sp. previously detected in cats from Brazil was described in lowland tapirs. Despite the controversy regarding the epidemiological threat of these protozoa, the detection of these tick-borne agents in wild free-living and captive mammals, even when asymptomatic, demonstrates the importance of monitoring, particularly in hotspots such as the state of Mato Grosso, to verify the circulation and genetic diversity, to anticipate the possible emergence of diseases, and even their consequences to other animals as well as humans.

An alternative method for determining the body condition index of the free-living South American coati

Assessing and monitoring the welfare of free-living mammals is not a usual process due to the logistical complications associated with their capture and sedation, collection and storage of biological samples and their release. In this context, non-invasive methods for monitoring wildlife constitute a good alternative approach for in situ conservation. Body condition index, as a measurement of health status, has been used in free-living mammals; its low value may be associated with negative effects on reproduction and survival. The present study aimed to generate an alternative and reliable non-invasive method and then determine the body condition index, based on previously-collected biometric measurements, without the need to capture and immobilise the animals. A total of 178 free-living Nasua nasua Linnaeus, 1766 were trapped, weighed and measured. Statistical methods were used, based on Boosted Regression Trees (BRT) using body mass, biometric measurements (body length, height and chest girth) and gender as explanatory variables. To assess the agreement between the real Body Condition Indices (BCIs) and the predicted values of BCIs, we explored the correlation between each model using the Bland-Altman method. This method showed a strong agreement between the predictive BRT models proposed (standardised residuals from a linear regression between body length and chest girth) and standardised residuals (linear regression between body mass and body length). The results obtained herein showed that BRT modelling, based on biometrical features, is an alternative way to verify the body conditions of coatis without the need to capture and immobilise the animals.

Ecology and Neurobiology of Fear in Free-Living Wildlife

The ecology of fear concerns the population-, community-, and ecosystem-level consequences of the behavioral interactions between predators and prey, i.e., the aggregate impacts of individual responses to life-threatening events. We review new experiments demonstrating that fear itself is powerful enough to affect the population growth rate in free-living wild birds and mammals, and fear of large carnivores—or the human super predator—can cause trophic cascades affecting plant and invertebrate abundance. Life-threatening events like escaping a predator can have enduring, even lifelong, effects on the brain, and new interdisciplinary research on the neurobiology of fear in wild animals is both providing insights into post-traumatic stress (PTSD) and reinforcing the likely commonality of population- and community-level effects of fear in nature. Failing to consider fear thus risks dramatically underestimating the total impact predators can have on prey populations and the critical role predator-prey interactions can play in shaping ecosystems.

Adiaspore development and morphological characteristics in a mouse adiaspiromycosis model

Lesions of adiaspiromycosis, a respiratory disease affecting wild animals, have been found mainly in dead mammals and free-living mammals captured for surveillance. No report has described an investigation of adiaspore formation progress in the lung. After establishing an experimental mouse model of intratracheal adiaspiromycosis infection with the causative agent Emmonsia crescens, we observed adiaspore development. The spores grew and reached a plateau of growth at 70 days post-infection. The median adiaspore diameter showed a plateau of around 40 μm. The characteristic three-layer cell-wall structure of adiaspores was observed in the lung at 70 days post-infection. We examined infection with a few spores, which revealed that adiaspores in the mouse lung progressed from intratracheal infection of at least 400 spores. Moreover, we developed adiaspores in vitro by culture in fetal bovine serum. Although most spores broke, some large spores were intact. They reached about 50 μm diameter. Thick cell walls and dense granules were found as common points between in vitro adiaspores and in vivo adiaspores. These models are expected to be useful for additional investigations of E. crescens adiaspores and adiaspiromycosis.

Non-invasive sampling in Itatiaia National Park, Brazil: wild mammal parasite detection

BackgroundNon-invasive sampling through faecal collection is one of the most cost-effective alternatives for monitoring of free-living wild mammals, as it provides information on animal taxonomy as well as the dynamics of the gastrointestinal parasites that potentially infect these animals. In this context, this study aimed to perform an epidemiological survey of gastrointestinal parasites using non-invasive faecal samples from carnivores and artiodactyls identified by stool macroscopy, guard hair morphology and DNA sequencing in Itatiaia National Park. Between 2017 and 2018, faeces from carnivores and artiodactyls were collected along trails in the park. The host species were identified through macroscopic and trichological examinations and molecular biology. To investigate the parasites, the Faust, Lutz and modified Ritchie and Sheather techniques and enzyme immunoassays to detect Cryptosporidium sp. antigens were used.ResultsA total of 244 stool samples were collected. The species identified were Chrysocyon brachyurus, Leopardus guttulus, Canis familiaris, Cerdocyon thous, Puma yagouaroundi, Leopardus pardalis, Puma concolor and Sus scrofa. There were 81.1% samples that were positive for parasites distributed mainly in the high part of the park. Helminths, especially eggs of the family Ascarididae, were more frequently detected in carnivore faeces (70.9%). Protozoa, especially Cryptosporidium sp., represented the highest frequency of infection in artiodactyl faeces (87.1%). This zoonotic protozoon was detected in eight mammalian species, including in a wild boar. High values of structural richness and Shannon and Simpson diversity indices were observed for the parasites, especially in the faeces of C. brachyurus. Significant differences in parasite diversity were observed between wild and domestic animals, such as C. brachyurus and C. familiaris, respectively, and between taxonomically distant species, such as C. brachyurus and S. scrofa. The highest values for parasite similarity were found among the species that frequented similar areas of the park, such as C. brachyurus and L. guttulus.ConclusionsThe animals and parasite infections were identified through the combination of three techniques. High frequency parasite structures were diagnosed. Zoonotic protozoa were found and mainly occurred in samples from introduced species.

Ehrlichia spp. and Anaplasma spp. in Xenarthra mammals from Brazil, with evidence of novel \u2018Candidatus Anaplasma spp.\u2019

Anaplasmataceae agents are obligatory intracellular Gram-negative α-proteobacteria that are transmitted mostly by arthropod vectors. Although mammals of the Superorder Xenarthra (sloths, anteaters, and armadillos) have been implicated as reservoirs for several zoonotic agents, only few studies have sought to detect Anaplasmataceae agents in this group of mammals. This study aimed to investigate the occurrence and genetic diversity of Anaplasma spp. and Ehrlichia spp. in blood and spleen samples of free-living Xenarthra from four different states in Brazil (São Paulo, Mato Grosso do Sul, Rondônia, and Pará). Nested and conventional PCR screening assays were performed to detect the rrs and dsb genes of Anaplasma spp. and Ehrlichia spp., respectively. The assays were positive in 27.57% (91/330) of the Anaplasma spp. and 24.54% (81/330) of the Ehrlichia spp. Of the 91 positive Anaplasma spp. samples, 56.04% were positive in a conventional PCR assay targeting the 23S–5S intergenic region. Phylogenetic and distance analyses based on the rrs gene allocated Anaplasma sequences from sloths captured in Rondônia and Pará states in a single clade, which was closely related to the A. marginale, A. ovis, and A. capra clades. The sequences detected in southern anteaters from São Paulo were allocated in a clade closely related to sequences of Anaplasma spp. detected in Nasua nasua, Leopardus pardalis, and Cerdocyon thous in Brazil. These sequences were positioned close to A. odocoilei sequences. Genotype analysis corroborated previous findings and demonstrated the circulation of two distinct Anaplasma genotypes in animals from north and southeast Brazil. The first genotype was new. The second was previously detected in N. nasua in Mato Grosso do Sul state. The intergenic region analyses also demonstrated two distinct genotypes of Anaplasma. The sequences detected in Xenarthra from Pará and Rondônia states were closely related to those in A. marginale, A. ovis, and A. capra. Anaplasma spp. sequences detected in Xenarthra from São Paulo and were allocated close to those in A. phagocytophilum. The analyses based on the dsb gene grouped the Ehrlichia spp. sequences with sequences of E. canis (São Paulo, Mato Grosso do Sul, and Pará) and E. minasensis (Rondônia and Pará). The data indicate the occurrence of E. canis and E. minasensis and two possible new Candidatus species of Anaplasma spp. in free-living mammals of the Superorder Xenarthra in Brazil.

Individual and Site-Specific Variation in a Biogeographical Profile of the Coyote Gastrointestinal Microbiota.

Most knowledge of the vertebrate gut microbiota comes from fecal samples; due to difficulties involved in sample collection, the upper intestinal microbiota is poorly understood in wild animals despite its potential to inform broad interpretations about host-gut microbe relationships under natural conditions. Here, we used 16S rRNA gene sequencing to characterize the microbiota of wild coyotes (Canis latrans) along the gastrointestinal tract, including samples from the duodenum, jejunum, ileum, caecum, ascending and descending colon, and feces. We used this intestinal profile to (1) quantify how intestinal site and individual identity interact to shape the microbiota in an uncontrolled setting, and (2) evaluate whether the fecal microbiota adequately represent other intestinal sites. Microbial communities in the large intestine were distinct from those in the small intestine, with higher diversity and a greater abundance of anaerobic taxa. Within each of the small and large intestine, individual identity explained significantly more among-sample variation than specific intestinal sites, revealing the importance of individual variation in the microbiota of free-living animals. Fecal samples were not an adequate proxy for studying upper intestinal environments, as they contained only half the amplicon sequence variants (ASVs) present in the small intestine at three- to four-fold higher abundances. Our study is a unique biogeographical investigation of the microbiota using free-living mammals rather than livestock or laboratory organisms and provides a foundational understanding of the gastrointestinal microbiota in a wild canid.

Landscape-scale patterns and drivers of novel mammal communities in a human-modified protected area

The role of protected areas as biodiversity repositories has become increasingly important in face of increased deforestation. By adding free-living exotic mammals, removing forest-dependent native ones, isolating forest patches from large protected areas and reducing landscape forest cover, human activities may drive mammal communities towards regional biotic homogenization. We assessed how landscape forest cover and proximity to the largest and best-preserved area of the Catimbau National Park—one of the largest protected areas of the Brazilian Caatinga—affect α- and β-diversity of medium- and large-sized mammals, considering native and exotic species. Using camera traps (total effort of 2340 cameras/day), we obtained 823 records of 15 species (8 natives and 7 exotics) in 18 landscapes of 1-km radius. We estimated diversity metrics within and among landscapes and used generalized linear models to assess the effect of forest loss and isolation on diversity metrics. As expected, forest loss decreased α-diversity of native species and increased the diversity and relative abundance of exotics. However, proximity to the preserved area showed weak effect on α-diversity, suggesting that this area does not work regionally as source for natives neither as ecological trap for exotics. Supporting the biotic homogenization hypothesis, β-diversity of natives decreased and β-diversity of exotics increased in more deforested landscapes. Yet, species composition was weakly related to forest cover and isolation. Our findings demonstrate that deforestation jeopardizes native species, favors exotics, and drives mammal communities towards biotic homogenization. Protected areas should be properly implemented to safeguard mammal diversity.

The mouse bile duct tapeworm, Hymenolepis microstoma in free-living small mammals in Slovakia: occurrence and genetic analysis

SummaryThe mouse bile duct tapeworm Hymenolepis microstoma, is a potentially zoonotic species with a wide variety of reported definitive hosts of rodent genera. In the present study the occurrence of H. microstoma in free-living small mammals in selected areas of Slovakia and the retrospective analysis of epidemiological data published in Slovakia were performed. Hymenolepis microstoma was detected in two animal species, the common shrew (Sorex araneus) and the European hamster (Cricetus cricetus) of 186 small mammals examined from two ecosystems, urban and natural ecosystem of national park. No mention about the presence of this parasite in Slovakia in the past was found following a bibliographical search. Partial sequences of the nuclear paramyosin gene showed the shrew isolate placed in a subclade together with H. microstoma from Portugal, with high bootstrap value for its differentiation from the sister species Hymenolepis nana. Similarly, the analysis of the nuclear ribosomal ITS region placed the hamster isolate in the cluster composed of H. microstoma from Australia, Spain and Portugal. The Slovak isolate was the most distinctive sample among available H. microstoma, differing in 1.4 – 1.9% of nucleotides from the remaining isolates. The difference (seven of 17 nucleotide positions) was partially due to indel polymorphisms associated with two and five nucleotides. To our knowledge, these are the first reports of H. microstoma in Central Europe and also the first record of infection in the common shrew. A recently indicated zoonotic potential of H. microstoma along with a possibility of its direct transmission between animals and/or humans without the need of intermediate hosts pose a public health concern in contaminated areas of Slovakia. The use of molecular techniques may substantially facilitate more thorough understanding of the epidemiological situation of H. microstoma and related tapeworms in various ecosystems of the country.

Feathers and hair as tools for non-destructive pollution exposure assessment in a mining site of the Iberian Pyrite Belt

Mining is responsible of releasing trace elements to the environment with potential negative effects on wildlife. Traditionally, wildlife exposure assessment has been developed by analyzing mainly environmental compartments or internal tissues. Nowadays, the use of non-destructive matrices such as hair or feathers has increased. Nevertheless, its use in free-living terrestrial mammals or in birds other than raptors or passerines is less frequent. The main objective of our study was to determine the potential for hair and feathers in a rabbit and bird species to be used as non-invasive proxy tissues for assessing internal metal concentrations at polluted sites from mining. We tested whether hair of European rabbit (Oryctolagus cuniculus) and feathers of red-legged partridge (Alectoris rufa) can be used as non-destructive biological monitoring tools of both essential (Cu, Zn) and non-essential (Pb, Cd, As) trace elements in a currently active copper mining site. We found significant different concentrations, particularly in non-essential elements, between reference area and mining site. Non-essential elements Pb and Cd showed higher correlations between tissues and hair/feathers, while few significant patterns were observed for essential elements such as Cu and Zn. Although feathers showed lower levels of correlation with internal tissues than hair, both could be useful as non-destructive biological monitoring tools. Further tissues, and more importantly, hair and feathers allowed discrimination between polluted and reference sites to indicate bioavailability and pollution status. In addition, hair and feathers can be used in monitoring pollution of an active mining site, being specially interesting for biomonitoring a certain period of time in the event of a particular episode of pollution, in addition to the chronic exposure. As occurred with hair in rabbits, feathers seem to be a good compartment to detect differences between a potential polluted area, such the surrounding of an active mine site, and a non-polluted area.

Altered Immunity of Laboratory Mice in the Natural Environment Is Associated with Fungal Colonization

Free-living mammals, such as humans and wild mice, display heightened immune activation compared with artificially maintained laboratory mice. These differences are partially attributed to microbial exposure as laboratory mice infected with pathogens exhibit immune profiles more closely resembling that of free-living animals. Here, we examine how colonization by microorganisms within the natural environment contributes to immune system maturation by releasing inbred laboratory mice into an outdoor enclosure. In addition to enhancing differentiation ofTcell populations previously associated withpathogen exposure, outdoor release increased circulating granulocytes. However, these "rewilded" mice were not infected by pathogens previously implicated in immune activation. Rather, immune system changes were associated with altered microbiota composition with notable increases in intestinal fungi. Fungi isolated from rewilded mice were sufficient in increasing circulating granulocytes. These findings establish a model to investigate how the natural environment impacts immune development and show that sustained fungal exposure impacts granulocyte numbers.

Multi-locus sequencing reveals a novel Bartonella in mammals from the Superorder Xenarthra.

The superorder Xenarthra consists of sloths, anteaters and armadillos, mammals originated from South America and currently distributed from the south of North America to the south of South America. The present study aimed to investigate the occurrence and genetic diversity of Bartonella spp. in blood and spleen samples from free-living Xenarthra mammals in the states of São Paulo (SP), Mato Grosso do Sul (MS), Rondônia (RO) and Pará (PA). Based on a quantitative real-time PCR (qPCR) assay, a Bartonella spp. nuoG gene fragment was detected in 1.51% (5/330) of the samples: 4 six-banded armadillos (Euphractus sexcinctus) sampled in the MS and 1 southern tamandua (Tamandua tetradactyla) sampled in the PA. Eight sequences (5 ftsZ, 2 gltA and 1 rpoB) were obtained in the conventional PCR assays. In both phylogenetic analyses based on Bayesian and distance (SplitsTree) methods, the obtained ftsZ, gltA and rpoB sequences were positioned in a distinct clade, but related to B.washoensis. The analysis of SplitsTree and genotype networks based on B.washoensis sequences from several hosts from various localities of the world showed that the sequences of the present study were allocated in a group separated from the other sequences, indicating that they probably originated from median vectors and large numbers of mutational events. Additionally, the analyses performed by BLAST showed low percentages of identities of the sequences obtained in the present study when compared to those previously deposited in GenBank. Therefore, we propose a new Candidatus to Bartonella occurring in Xenarthra in Brazil. The present study was the first to report the occurrence of Bartonella sp. in mammals of the superorder Xenarthra in the world, and it was the first to describe a new Candidatus related to B.washoensis in Brazil.

What’s in a whisker? High-throughput analysis of twenty-eight C19 and C21 steroids in mammalian whiskers by ultra-performance convergence chromatography-tandem mass spectrometry

Obtaining longitudinal endocrinological data from free-ranging animals remains challenging. Steroid hormones can be extracted sequentially from non-invasively sampled biologically inert keratinous tissues, such as feathers, nails, hair and whiskers. However, uncertainty regarding the type and levels of steroids incorporated into such tissues complicates their utility in wildlife studies. Here, we developed a novel, comprehensive method to analyze fourteen C19 and fourteen C21 steroids deposited chronologically along the length of seal whiskers in a single, 6-minute chromatographic step, using ultra-performance convergence chromatography-tandem mass spectrometry. The limits of detection and quantification ranged from 0.01 to 2 ng/mL and from 0.1 to 10 ng/mL, respectively. The accuracy and precision were within acceptable limits for steroids at concentrations ≥2 ng/mL. The recovery (mean = 107.5% at 200 ng/mL), matrix effect and process efficiency of steroids evaluated, using blanked whisker matrix samples, were acceptable. The method was applied to the analysis of steroid hormone levels in adult female whisker segments obtained from southern elephant seals (Mirounga leonina), n = 10, and two fur seal species, Antarctic fur seals (Arctocephalus gazella; n = 5) and subantarctic fur seals (Arctocephalus tropicalis; n = 5), sampled between 2012 and 2017. In the whisker subsamples analyzed (n = 71), the median concentration of steroid hormones detected above the LOQ ranged from 2.0 to 273.7 pg/mg. This was the first extraction of multiple C19 and C21 steroids, including their C11-oxy metabolites, from the whiskers of mammals. Measuring hormones sequentially along the whisker lengths can contribute to our understanding of the impact of stress associated with environmental/climate changes that affect the health, survival of organisms, as well as to delineate the reproductive cycles of free-living mammals with cryptic life stages.

<p class="Body"><strong>Rickettsial survey and ticks infesting small mammals from the Amazon forest in midwestern Brazil</strong></p>

In the present study, samples of tick, tissue and blood from free-living wild small mammals (rodents and marsupials) captured in two municipalities from the Amazon biome of the Mato Grosso state, were molecularly tested for rickettsial infection. A total of 148 mammal specimens (46 rodents and 102 marsupials) were trapped, and 2,700 Amblyomma ticks (2,000 larvae and 700 nymphs) were collected. Ticks were recognized into four Amblyomma species: Amblyomma cajennense sensu stricto, Amblyomma coelebs, Amblyomma humerale, and Amblyomma scalpturatum, with new data for tick-host associations from small mammals in the Amazon biome. All tissue and blood samples of small mammals tested by PCR for rickettsial detection were negative. However, concerning tick-Rickettsia associations, Rickettsia amblyommatis was detected in all four tick species identified in the present study, being the first record for A. scalpturatum ticks. Furthermore, an uncharacterized species of Rickettsia belonging to the spotted fever group was detected in A. humerale as well.

Occurrence of Gastrointestinal Parasites in Small Mammals from Germany.

An increase in zoonotic infections in humans in recent years has led to a high level of public interest. However, the extent of infestation of free-living small mammals with pathogens and especially parasites is not well understood. This pilot study was carried out within the framework of the "Rodent-borne pathogens" network to identify zoonotic parasites in small mammals in Germany. From 2008 to 2009, 111 small mammals of 8 rodent and 5 insectivore species were collected. Feces and intestine samples from every mammal were examined microscopically for the presence of intestinal parasites by using Telemann concentration for worm eggs, Kinyoun staining for coccidia, and Heidenhain staining for other protozoa. Adult helminths were additionally stained with carmine acid for species determination. Eleven different helminth species, five coccidians, and three other protozoa species were detected. Simultaneous infection of one host by different helminths was common. Hymenolepis spp. (20.7%) were the most common zoonotic helminths in the investigated hosts. Coccidia, including Eimeria spp. (30.6%), Cryptosporidium spp. (17.1%), and Sarcocystis spp. (17.1%), were present in 40.5% of the feces samples of small mammals. Protozoa, such as Giardia spp. and amoebae, were rarely detected, most likely because of the repeated freeze-thawing of the samples during preparation. The zoonotic pathogens detected in this pilot study may be potentially transmitted to humans by drinking water, smear infection, and airborne transmission.

Physiological and behavioral responses to anthropogenic stressors in a human-tolerant mammal

Abstract As humans continue to alter natural habitats, many wild animals are facing novel suites of environmental stimuli. These changes, including increased human–wildlife interactions, may exert sublethal impacts on wildlife such as alterations in stress physiology and behavior. California ground squirrels (Otospermophilus beecheyi) occur in human-modified as well as more pristine environments, where they face a variety of anthropogenic and naturally occurring threats. This makes this species a valuable model for examining the effects of diverse challenges on the physiology and behavior of free-living mammals. To explore potential sublethal effects of habitat modification on O. beecheyi, we compared body masses, behaviors, and fecal glucocorticoid metabolite (FGM) levels for free-living squirrels in human-disturbed versus undisturbed habitats. Prior to these analyses, we validated the use of FGMs in this species by exposing captive O. beecheyi to pharmacological and handling challenges; both challenges produced significant increases in FGMs in the study animals. While FGM responses were repeatable within captive individuals, responses by free-living animals were more variable, perhaps reflecting a greater range of life-history traits and environmental conditions within natural populations of squirrels. Animals from our human-disturbed study site had significantly higher FGMs, significantly lower body masses, and were significantly less behaviorally reactive to humans than those from our more pristine study site. Thus, despite frequent exposure of California ground squirrels to human impacts, anthropogenic stressors appear to influence stress physiology and other phenotypic traits in this species. These findings suggest that even human-tolerant mammalian species may experience important sublethal consequences due to human modifications of natural habitats.

Integration of multi-omics data from re-wilded laboratory mice to identify key parameters that determine immune heterogeneity and activation

Abstract Current research on immunology are largely based on clean laboratory mice kept in specific pathogen free (SPF) environments. They have the advantage of being inbred, genetically homogeneous and can be manipulated genetically in disease models. However, humans as with all free-living mammals face a more complex environment and are exposed to various food resources, microbial experiences, thermogenic changes, and must constantly respond to environmental challenges. We have established a unique experimental system in which laboratory mice are “re-wilded” through release into an outdoor enclosure facility. Here, we use multi-parameter assays including 16S/Metagenomic sequencing, intestinal RNA-sequencing, and 34 parameters of flow cytometry to explain heterogeneity of immune responses from exposure to the wild environment. Increased immune activation of re-wilded mice occur in the absence of viral, bacterial or parasitic pathogen exposure in this enclosure, including increase of CD4+ and CD8+ memory T cells, effector T cells, innate lymphoid cells (ILCs), circulating neutrophils, reduction in naïve T cells, and increased expression of costimulatory molecules on antigen presenting cells. When we examined cytokine production in response to ex vivo stimulation of mesenteric lymph node cells with 8 bacterial and fungal stimuli, the mesenteric lymph node cells from re-wilded mice are poised for different responses via robust induction of cytokines than laboratory mice. By using machine learning models, we are integrating these multi-omic datasets to better predict the association between environmental and host genetic factors on driving heterogeneity of immune responses in the re-wilded mice.

Detection of Rickettsia spp. in ticks associated to wild mammals in Northeastern Brazil, with notes on an undetermined Ornithodoros sp. collected from marsupials

We report tick infestations and rickettsial detection in ticks infesting free-living wild mammals (Monodelphis domestica, Tolypeutes tricinctus, Thrichomys inermis and Kerodon rupestris) captured in the Caatinga ecoregion of Bahia state, northeastern Brazil, during September to December 2016. Overall, 117 ticks (61 larvae, 25 nymphs, 25 males, 6 females) belonging to two genera, and at least three species were collected: Amblyomma auricularium, Amblyomma parvum, Amblyomma sp., Ornithodoros rietcorreai and an unidentified Ornithodoros sp. We provide new host records to the rodent T. inermis parasitized by larva and nymphs of A. auricularium and to the marsupial M. domestica infested by larvae of A. auricularium. Furthermore, we describe new tick-host association for larvae of O. rietcorreai on the rodents K. rupestris and T. inermis. Concerning tick-Rickettsia associations, we detected Rickettsia amblyommatis and an uncharacterized species of Rickettsia belonging to the spotted fever group (SFG) in both A. auricularium and A. parvum. Additionally, 'Candidatus Rickettsia andeanae' was detected in A. parvum as well.