Fox Feces Research Articles

A comparison of the diet and fine‐scale distribution of sympatric Tibetan and red foxes in Qinghai, PR China

We compared the diet and the spatial distribution of the Tibetan fox Vulpes ferrilata and the red fox Vulpes vulpes in the Tibetan plateau, to elucidate mechanisms of coexistence for these two sympatric canids and to clarify their roles as definitive hosts for zoonotic Echinococcus parasites. Diet and fine‐scale distribution patterns were assessed by fecal DNA analysis. A total of 45 fecal samples (15 belonging to Tibetan fox, 30 belonging to red fox were collected from 15 sites into three of which contained only Tibetan fox feces, six only red fox feces, and six contained feces of both species. The abundance of pika burrows, a key prey item for both species, did not differ among the sites. Food composition analysis, estimated using a point‐frame method, revealed slight but insignificant differences between the two species. Tibetan foxes consumed primarily mammals, whereas red foxes consumed primarily insects. The dietary range of the Tibetan fox was narrower than that of the red fox but there was little dietary overlap between the two species. These findings suggest that the weak partitioning of food resources between Tibetan and red foxes can facilitate their coexistence even within the same habitat where they share the same key prey items, i.e. small mammals such as pikas. These dietary differences between the two fox species also suggest that the Tibetan fox is a more important definitive host for Echinococcus on the Tibetan plateau than is the red fox.

Identification of the CART neuropeptide circuitry processing TMT-induced predator stress.

Abundance of cocaine- and amphetamine-regulated transcript (CART) neuropeptide in the limbic areas like the olfactory system, central nucleus of amygdala (CeA), ventral bed nucleus of stria terminalis (vBNST) and the hypothalamus suggests involvement of the peptide in emotive processing. We examined the role of CART in mediating fear, a strong emotion with profound survival value. Rats, exposed to 2,4,5-trimethyl-3-thiazoline (TMT), a predator related cue extracted from fox feces, showed significant increase in freezing, escape and risk assessment behavior, whereas grooming was reduced. Neuronal activity was up-regulated in the CeA and vBNST in terms of increased immunoreactivity in CART elements and c-Fos expression. Increased expression of both the markers was also seen in some discrete magnocellular as well as parvicellular subdivisions of the paraventricular nucleus (PVN). However, CART containing mitral cells in the main or accessory olfactory bulb did not respond. CART antibody was stereotaxically injected bilaterally into the CeA to locally immunoneutralize endogenous CART. On exposure to TMT, these rats showed reduced freezing, risk assessment and escape behavior while grooming was restored to normal value. We suggest that the CART signaling in the CeA and vBNST, but not in the olfactory system, might be an important component of the innate fear processing, and expression of stereotypic behavior, while CART in the PVN subdivisions might mediate the neuroendocrine response to predator stress.

Does predation risk, through moon phase and predator cues, modulate food intake, antipredatory and physiological responses in wood mice (Apodemus sylvaticus)?

Predation influences the ecology and behaviour of prey species and it is well known that the risk of predation affects prey’s decision making. We investigated whether predation risk through moon phase and exposure to the faecal odour of a natural predator, the red fox Vulpes vulpes, affect feeding behaviour and physiological response in wood mice (Apodemus sylvaticus). Antipredatory response was studied by live trapping under new and full moon in odourless control areas and areas experimentally manipulated with red fox fresh faeces. Food intake by individuals was determined as the amount of bait remaining in each trap and the physiological response was measured non-invasively analysing faecal corticosterone metabolites (FCM). Traps treated with faeces of red fox were the most avoided, and this avoidance was more significant during full moon. Food intake by wood mice varied according to the moon phase being significantly lower under full moon nights. We found sex, breeding condition and weight of individuals explaining the variation found in FCM concentrations, but no changes in FCM levels due to moon phase or exposure to red fox faeces were detected. These results indicate that wood mice avoid red fox faecal odour and this antipredatory response as well as feeding behaviour are significantly influenced by moon phase. However, no physiological response was found due to predation risk suggesting that wood mice do not take these predation cues enough reliable to experience physiological changes.

Dieta de la zorra gris Urocyon cinereoargenteus y su contribución a la dispersión de semillas en la costa de Oaxaca, México

Introduction: An important number of mammals of the order Carnivora are opportunists that consume primarily small mammals, although they can amplify their diet with other larger vertebrates and arthropods. Fruits have also been reported in the diet of some carnivores; however, their role as agents of seed dispersal has not been well documented thus far. In this study we analyzed the diet of the grey fox in tropical deciduous forest in the state of Oaxaca throughout the annual seasons, establishing composition and seasonal variation, and determined if seed ingestion contributed to seed dispersal, and therefore favoring germination. Methods: A total of 75 fresh grey fox feces were identified and quantified to determine composition and number of seeds at the Jardin Botanico Regional Puerto Escondido (JBPE) in the coastal region of Oaxaca, Mexico. Identification and quantification of feces composition was based on a presence/absence analysis and then establish frequencies and percentages of food categories, and proportion and germination speed of ingested seeds. Results: Food categories reported in feces were as follow: seeds in 56 of 75 feces representing 74.67%, vertebrates in 45 feces (60%) and invertebrates in 40 feces representing 53.33%. Diet variation was observed by season and by moth, and trophic niche breath varied significantly between seasons (Fig. 1). Identified seeds belonged to seven species. Additionally, germination percentages of the seeds of these species through endozoochory were higher than those obtained from the control seeds (Table 1). Discussion and conclusion: The grey fox is a legitimate seed disperser that consequently generates a positive effect on rates and speed of germination of the utilized species. Furthermore, seasonal variation of seed presence observed in feces is influenced by availability of these seeds in the environment; which puts on evidence the high level of adaptability by this carnivore. Key words: Niche breath, disperser, diet, opportunist, germination percentage, seasonal variation.

Effects of juvenile exposure to predator odor on adolescent and adult anxiety and pain nociception

Clinical researchers have tracked patients with early life trauma and noted generalized anxiety disorder, unipolar depression, and risk-taking behaviors developing in late adolescence and into early adulthood. Animal models provide an opportunity to investigate the neural and developmental processes that underlie the relationship between early stress and later abnormal behavior. The present model used repeated exposure to 2,3,5-trimethyl-3-thiazoline (TMT), a component of fox feces, as an unconditioned fear-eliciting stimulus in order to induce stress in juvenile rats aged postnatal day (PND) 23 through 27. After further physical maturation characteristic of the adolescent stage (PND 42), animals were tested using an elevated plus maze (EPM) for anxiety and plantar test (Hargreaves method) for pain to assess any lingering effects of the juvenile stress. To assess how an additional stress later in life affects anxiety and pain nociception, PND 43 rats were exposed to inescapable shock (0.8mA) and again tested on EPM and plantar test. A final testing period was conducted in the adult (PND 63) rats to assess resulting changes in adult behaviors. TMT-exposed rats were significantly more anxious in adolescence than controls, but this difference disappeared after exposure to the secondary stressor. In adulthood, but not in adolescence, TMT-exposed rats demonstrated lower pain sensitivity than controls. These results suggest that early life stress can play a significant role in later anxiety and pain nociception, and offer insight into the development and manifestation of anxiety- and trauma-related disorders.

Laboratory assessment of sensitive molecular tools for detection of low levels of Echinococcus multilocularis-eggs in fox (Vulpes vulpes) faeces.

BackgroundIn endemic areas with very low infection prevalence, the frequency and intensity of Echinococcus multilocularis can be extremely low. This necessitates efficient, specific and sensitive molecular tools. We wanted to compare the existing molecular tools, used in the Norwegian national surveillance programme, and compare these with new techniques for detection of this zoonotic pathogen in fox faeces. Here we present the results of screening samples containing a known level of E. multilocularis eggs with two highly sensitive DNA isolation and extraction methods combined with one conventional PCR and three real-time PCR methods for detection.MethodsWe performed a comparison of two extraction protocols; one based on sieving of faecal material and one using targeted DNA sampling. Four methods of molecular detection were tested on E. multilocularis-egg spiked fox faeces.ResultsThere were significant differences between the multiplex PCR/egg sieving DNA extraction methods compared to the new DNA fishing method and the three real-time PCR assays. Results also indicate that replicates of the PCR-reactions improve detection sensitivity when egg numbers are low.ConclusionsThe results indicate that the use of real-time PCR combined with targeted DNA extraction, improves the sensitivity of E. multilocularis detection in faecal samples containing low numbers of E. multilocularis eggs. Results also indicate the importance of replicates of the PCR-reactions when pathogen levels are low.

Real time PCR to detect the environmental faecal contamination by Echinococcus multilocularis from red fox stools

The oncosphere stage of Echinococcus multilocularis in red fox stools can lead, after ingestion, to the development of alveolar echinococcosis in the intermediate hosts, commonly small mammals and occasionally humans. Monitoring animal infection and environmental contamination is a key issue in public health surveillance. We developed a quantitative real-time PCR technique (qPCR) to detect and quantify E. multilocularis DNA released in fox faeces. A qPCR technique using a hydrolysis probe targeting part of the mitochondrial gene rrnL was assessed on (i) a reference collection of stools from 57 necropsied foxes simultaneously investigated using the segmental sedimentation and counting technique (SSCT) (29 positive for E. multilocularis worms and 28 negative animals for the parasite); (ii) a collection of 114 fox stools sampled in the field: two sets of 50 samples from contrasted endemic regions in France and 14 from an E. multilocularis-free area (Greenland). Of the negative SSCT controls, 26/28 were qPCR-negative and two were weakly positive. Of the positive SSCT foxes, 25/29 samples were found to be positive by qPCR. Of the field samples, qPCR was positive in 21/50 (42%) and 5/48 (10.4%) stools (2 samples inhibited), originating respectively from high and low endemic areas. In faeces, averages of 0.1pg/μl of DNA in the Jura area and 0.7pg/μl in the Saône-et-Loire area were detected. All qPCR-positive samples were confirmed by sequencing. The qPCR technique developed here allowed us to quantify environmental E. multilocularis contamination by fox faeces by studying the infectious agent directly. No previous study had performed this test in a one-step reaction.

Exposure to predator odor influences the relative use of multiple memory systems: Role of basolateral amygdala

In a dual-solution plus-maze task in which both hippocampus-dependent place learning and dorsolateral striatal-dependent response learning provide an adequate solution, the relative use of multiple memory systems can be influenced by emotional state. Specifically, pre-training peripheral or intra-basolateral (BLA) administration of anxiogenic drugs result in the predominant use of response learning. The present experiments were designed to extend these findings by examining whether exposure to a putatively ethologically valid stressor would also produce a predominant use of response learning. In experiment 1, adult male Long-Evans rats were exposed to either a predator odor (trimethylthiazoline [TMT], a component of fox feces) or distilled water prior to training in a dual-solution water plus maze task. On a probe trial 24h following task acquisition, rats previously exposed to TMT predominantly displayed response learning relative to control animals. In experiment 2, rats trained on a single-solution plus maze task that required the use of response learning displayed enhanced acquisition following pre-training TMT exposure. In experiment 3, rats exposed to TMT or distilled water were trained in the dual-solution task and received post-training intra-BLA injections of the sodium channel blocker bupivacaine (1.0% solution, 0.5μl) or saline. Relative to control animals, rats exposed to TMT predominantly displayed response learning on the probe trial, and this effect was blocked by neural inactivation of the BLA. The findings indicate that (1) the use of dorsal striatal-dependent habit memory produced by emotional arousal generalizes from anxiogenic drug administration to a putatively ecologically valid stressor (i.e. predator odor), and (2) the BLA mediates the modulatory effect of exposure to predator odor on the relative use of multiple memory systems.

Possible Spore Dispersal of a Bird-Nest FernAsplenium setoiby Bonin flying foxesPteropus pselaphon

Fern spores are generally considered to be dispersed by abiotic processes, particularly anemochory (wind dispersal). Recently, it was shown that Bonin flying foxes Pteropus pselaphon feed on fronds of Asplenium setoi, a species of bird-nest fern, because its spores were found in the flying fox feces (Nakamura et al. 2008). This discovery implied that Bonin flying foxes might serve as biotic agents of Asplenium spore dispersal. However, it is not known whether the spores that pass through the gut of the Bonin flying fox maintain their germinability and viability. Flying foxes Pteropus spp. frequently interact with plants as pollinators and seed dispersers, particularly on isolated oceanic islands (Cox et al. 1991; Elmqvist et al. 1992; Rainey et al. 1995; Nyhagen et al. 2005). Insular flying foxes, members of the genus Pteropus, eat various parts of many plants species, including fruits, flowers, and leaves (Funakoshi et al. 1993; Entwistle and Corp 1997; Banack 1998; Nyhagen et al. 2005; Inaba et al. 2005; Nakamoto et al. 2007). Insular flying foxes appear to have a generalist diet strategy; they consume a taxonomically nonrandom set of plant species and do not focus on the core plant taxa on small oceanic islands with unpredictable fruit resources. In terms of their diet strategy, they can, therefore, be considered as sequential specialists (Banack 1998). Flying foxes squeeze plant pulp and then drink the juice or sap and do not swallow seeds > 5 mm in diameter (Richards 1995). The germination of small seeds (< 5 mm) passed through the gut has been verified in some flying fox species (Entwistle and Corp 1997; Nakamoto et al. 2007). Parsons et al. (2007) reported that bryophyte fragments found in feces of the spectacled flying fox Pteropus conspicillatus, found in Australian tropical forests, grew when cultured, suggesting that flying foxes can play a role as dispersal vectors of mosses. Fern spores are diaspores and are generally considered to be dispersed by wind. If spores in the feces germinate and develop into prothallia, then the flying foxes might be able to disperse the spores. Furthermore, in many ferns, including Asplenium setoi, growth from spores to sporophytes requires sexual reproduction (fertilization) with outbreeding (outcrossing) between two different prothallia (gametophytes). Many ferns have selfincompatibility in the prothallium and cannot perform self-fertilization (selfing) (Soltis and Soltis 1992). Biotic dispersal processes favor ferns with these characteristics, because several spores of the same species tend to be dispersed together. In this study, we used a germination test to examine whether spores of a bird-nest fern retain viability and fertility after their passage through the digestive tract of flying foxes. We performed DNA analysis of the ferns, as it is almost impossible to morphologically distinguish A. setoi from the related species of the genus Asplenium based on the young fronds.

Fox baiting against Echinococcus multilocularis: Contrasted achievements among two medium size cities

In Europe, most cities are currently colonized by red foxes (Vulpes vulpes), which are considered to be the main definitive host of the zoonotic cestode Echinococcus multilocularis. The risk of transmission to humans is of particular concern where high fox populations overlap with high human populations. The distribution of baits containing praziquantel has successfully reduced the infection pressure in rural areas and in small plots within large cities. The purpose of this study was to assess its efficiency in two medium size cities (less than 100,000 inhabitants) in areas of high human alveolar echinococcosis incidence. From August 2006 to March 2009, 14 baiting campaigns of praziquantel treatment were run in Annemasse and Pontarlier (Eastern France), each of which encompassed 33km2, with a density of 40baits/km2. The bait consumption appeared to be lower in strictly urban context compared to suburban areas (78.9% vs. 93.4%) and lower in Annemasse than in Pontarlier (82.2% vs. 89.5%).During our study, the prevalence of E. multilocularis, as assessed by EM-ELISA on fox faeces collected in the field in Annemasse, was lower within the treated area than in the rural control area. A “before/during” treatment comparison revealed a significant decrease of spring prevalence from 13.3% to 2.2%. No significant change in prevalence was detected in Pontarlier (stable prevalence: 9.1%) where the contamination of the treated area followed the temporal trend observed in the control area. There, a greater resilience of the parasite's life cycle, probably due to a strong pressure of recontamination from outside the treated area, may have counteracted the prophylaxis treatment.These contrasted outcomes suggest that the frequency of fox anthelmintic treatment should be adapted to the local situation.

Survey on Helminths in the Small Intestine of Wild Foxes in Qinghai, China

ABSTRACTThe intestinal helminth fauna of Tibetan sand foxes (Vulpes ferrilata) and red foxes (Vulpes vulpes) inhabiting in Qinghai, China, was evaluated by conducting necropsy of hunted foxes and fecal egg examination of field-collected feces. In northeast and south Qinghai, 36 foxes were necropsied, and the species of foxes and the parasites detected were identified by the DNA barcoding. In 27 red foxes and 9 Tibetan sand foxes examined, Mesocestoides litteratus (total prevalence: 64%), Toxascaris leonina (50%), Taenia pisiformis (8%) and Taenia crassiceps (8%) were found in both species of foxes. Echinococcus shiquicus (8%) and Taenia multiceps (6%) were found only in Tibetan sand foxes. Echinococcus multilocularis (3%) and Alaria alata (8%) were found only in red foxes. In the fecal egg examination of the rectal feces, 100% of taeniid cestodes, 73% of Toxascaris and 27% of Mesocestoides worm-positive samples showed egg-positive, indicating that coprological survey for parasite eggs could only provide partial information of intestinal parasite fauna. For field-collected feces, molecular identification of feces origins and fecal egg examination were performed. In 15 Tibetan sand fox and 30 red fox feces, we found E. multilocularis eggs in one feces of Tibetan sand fox. The present study indicated that the upper intestinal helminth fauna of the two fox species in Qinghai does not differ significantly and both species would play an important role in the maintenance of taeniid cestodes.

Faecal sampling along trails: a questionable standard for estimating red fox Vulpes vulpes abundance

In most studies that estimate abundance of foxes from faeces counts, scanning is done along trails and roads or along linear features such as hedges, because it is supposed that foxes defecate mainly along these structures. As a consequence, only part (i.e. trails or linear features) of the total habitat is searched and results are possibly biased if usage by foxes of these searched features is subject to spatial or temporal variation. We therefore investigated three methods for counting red fox Vulpes vulpes faeces, that differ in the shape of the sampling units: trails and two alternatives; i.e. transects and squares. We searched for faeces using these three methods in two study areas (the Upper Rhine Valley and the Black Forest valleys) at 61 study plots and found a total of 257 fox faeces. Methods for estimating abundance should ideally have high accuracy and high precision. As actual fox densities in the areas were unknown, we were unable to assess the accuracy of our sampling methods and thus focused on method precision. We fit separate negative binomial regression models for each method with the number of faeces found as the dependent variable and a set of landscape variables as possible explanatory variables. The transect method detected significant differences in the number of faeces found between the study areas and was most precise. Even though we did find more faeces with the trail method, the precision of this method was lower than that of the transect method. For the methods trail and square, variance in the number of faeces found was large in comparison to their mean. Bias caused by methods that only sample part of the habitat is not limited to faecal counts and red fox studies, but can also occur with other species and methods.

Altered anxiety and defensive behaviors in Bax knockout mice

Developmental neuronal cell death is critically regulated by the pro-death protein Bax. Bax−/− mice exhibit increased neuron number, the elimination of several neural sex differences, and altered socio-sexual behaviors. Here we examined the effects of Bax gene deletion on anxiety and defensive behaviors by comparing the responses of male and female wildtype and Bax−/− mice to two different tests. On the elevated plus maze, Bax−/− mice of both sexes made more entries into and spent more time in the outer portion of open arms, indicating decreased anxiety compared to wildtype animals. Next, we exposed mice to two odors: trimethylthiazoline (TMT), an olfactory component of fox feces that rodents find aversive, and butyric acid (BA), an aversive odor without ecological significance. Each odor was presented individually and all animals were tested with both odors in a counterbalanced design. TMT was consistently more aversive than BA across a variety of behaviors (e.g., mice spent less time close to the odor source). Overall, Bax −/− mice showed fewer stretch approaches to both TMT and BA than wildtypes, but they avoided the odor source more (e.g., fewer contacts and less time spent in proximity). Finally, no effect of genotype was seen in baseline olfactory behavior; all mice were able to locate a buried food item, demonstrating that Bax−/− mice do not have impaired olfaction per se. Collectively, these data suggest a change in strategy with anxiety and defensive behaviors in Bax−/− mice, indicating that alterations in cell number affect more general mechanisms of fear and anxiety in addition to behaviors directly related to reproduction.

Brain Processing of Biologically Relevant Odors in the Awake Rat, as Revealed by Manganese-Enhanced MRI

BackgroundSo far, an overall view of olfactory structures activated by natural biologically relevant odors in the awake rat is not available. Manganese-enhanced MRI (MEMRI) is appropriate for this purpose. While MEMRI has been used for anatomical labeling of olfactory pathways, functional imaging analyses have not yet been performed beyond the olfactory bulb. Here, we have used MEMRI for functional imaging of rat central olfactory structures and for comparing activation maps obtained with odors conveying different biological messages.Methodology/Principal FindingsOdors of male fox feces and of chocolate flavored cereals were used to stimulate conscious rats previously treated by intranasal instillation of manganese (Mn). MEMRI activation maps showed Mn enhancement all along the primary olfactory cortex. Mn enhancement elicited by male fox feces odor and to a lesser extent that elicited by chocolate odor, differed from that elicited by deodorized air. This result was partly confirmed by c-Fos immunohistochemistry in the piriform cortex.Conclusion/SignificanceBy providing an overall image of brain structures activated in awake rats by odorous stimulation, and by showing that Mn enhancement is differently sensitive to different stimulating odors, the present results demonstrate the interest of MEMRI for functional studies of olfaction in the primary olfactory cortex of laboratory small animals, under conditions close to natural perception. Finally, the factors that may cause the variability of the MEMRI signal in response to different odor are discussed.

Context‐dependent fruit–frugivore interactions: partner identities and spatio‐temporal variations

Fruit–frugivore interactions are crucial for the dynamics and regeneration of most forested ecosystems. Still, we lack an understanding of the potential variation in the sign and strength of such interactions in relation to variations in the spatial and temporal ecological context. Here, we evaluated spatial (three sites) and temporal (two fruiting seasons) local variation in the sign (seed predation versus dispersal) and strength (frequency and quantity) of the interactions among six frugivorous mammals and a community of Mediterranean fleshy‐fruited shrubs. We examined mammal faecal samples and quantified frequency of seed occurrence, number of seeds per faecal sample, seed species diversity and quality of seed treatment (i.e. percentage of undamaged seeds). The frequency of seed occurrence and number of seeds per faecal sample strongly varied among dispersers, sites, seasons and fruit species. For instance, fox Vulpes vulpes faeces showed between 6 and 40 times more seeds than wild boar Sus scrofa faeces in seasons or sites in which Rubus and Juniperus seeds were dominant. However, in seasons or sites dominated by Corema seeds, wild boar faeces contained up to seven times more seeds than fox faeces. Mammalian carnivores (fox and badger, Meles meles) treated seeds gently, acting mostly as dispersers, whereas deer (Cervus elaphus and Dama dama) acted mainly as seed predators. Interestingly, rabbit Oryctolagus cuniculus acted as either mostly seed disperser or seed predator depending on the plant species. Our results indicated that the sign of fruit–frugivore interactions depended mainly on the identity of the partners. For a particular fruit–frugivore pair, however, our surrogate of interaction strength largely varied with the spatio‐temporal context (year and habitat), leading to a low specificity across the seed–frugivore network. The high spatio‐temporal variability of seed dispersal (in quantity, quality and seed diversity) by different frugivores would confer resilience against unpredictable environmental conditions, such as those typical of Mediterranean ecosystems.

Specific detection of Echinococcus spp. from the Tibetan fox (Vulpes ferrilata) and the red fox (V. vulpes) using copro-DNA PCR analysis

There are three Echinococcus species, Echinococcus granulosus, E. multilocularis, and E. shiquicus, which are distributed on the vast area of pastureland on the eastern Tibetan plateau in China. Tibetan foxes (Vulpes ferrilata) have been determined to be the main wild definitive host of E. multilocularis and E. shiquicus, but little information is available on the prevalence of these two parasites in Tibetan foxes. Consequently, the copro-prevalence of these parasites in foxes from the eastern Tibetan plateau was evaluated in this study. For each copro-DNA sample extracted from fox feces, a 133-bp segment of EgG1 Hae III was used to screen for infection with E. granulosus. Multiplex nested polymerase chain reaction (PCR) analysis was used to target an 874-bp segment of the mitochondrial COI gene to distinguish E. multilocularis and E. shiquicus. Among 184 fecal samples, 120 were from Tibetan foxes and six from red foxes (Vulpes vulpes). Of the fecal samples from Tibetan foxes, 74 (giving a copro-prevalence of 62%) showed the presence of Echinococcus spp.: 23 (19%) were found to contain E. multilocularis, 32 (27%) E. shiquicus, and 19 (16%) showed mixed infection with both E. multilocularis and E. shiquicus. Two fecal samples from red foxes were found to be infected with E. multilocularis. No fox feces were found to be infected with E. granulosus. Tests on zinc finger protein genes and a 105-bp fragment of the Sry gene found no significant difference in the prevalence of the two parasites between sexes. The efficiency of our multiplex nested PCR methods were compared with previous polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) methods and some problems associated with the copro-PCR were discussed.

Fear-like behavioral responses in mice in different odorant environments: Trigeminal versus olfactory mediation under low doses

Odors can have repulsive effects on rodents based on two complementary adaptive behaviors: the avoidance of predator odors (potentially dangerous) and the avoidance of trigeminal stimulants (potentially noxious). The present study aimed to compare the behavioral effects on mice of odors according to their trigeminal properties and ecological significance. We used three different odors: 2,4,5-trimethylthiazoline (TMT: a fox feces odor frequently used to elicit fear-induced behaviors), toluene (a strong stimulant of the trigeminal system) and phenyl ethyl alcohol (PEA: a selective stimulant of the olfactory system). First, we checked preference and avoidance behaviors in mice with and without anosmia towards these odors to ensure their olfactory/trigeminal properties. Secondly, we used a standard test (open-field and elevated plus-maze) to assess the behaviors of mice when exposed to these odors. The results show that the anosmic and control mice both avoided TMT and toluene odors. In the open-field and the elevated plus-maze, mice exhibited "anxious" behaviors when exposed to TMT. Conversely, exposure to PEA induced "anxiolytic" effects confirmed by low blood corticosterone levels resulting from completion of the elevated plus-maze. Compared with TMT exposure, toluene exposure induced moderate "anxious" effects.

Electrophysiological responses of rat olfactory tubercle neurons to biologically relevant odours

Biologically relevant odours were used to stimulate olfactory tubercle neurons in anaesthetized male rats. Among 120 recorded neurons, 118 showed spontaneous activity (mean firing rate, 15.0 ± 1.4 spikes/s). Ninety-eight neurons were exposed to at least one of the four following odour sources: an empty vial, or a vial containing food pellets (familiar odour), a sample of oestrous rat faeces (conspecific sexual odour), or a sample of male fox faeces (predator odour). The proportion of neurons responding with a change in activity was significantly linked to the odour applied. Repetition of the stimulation with the same odour elicited the same activity change. Between 50 and 70% of neuronal activity changes were not accompanied by respiration changes. Fifty-six neurons were exposed successively to all four odours, and 38 of them showed an activity change in response to at least one. The response of a neuron to an odour was not affected by its response to the previous one, and no neuron responded in the same manner to all odours. Conversely, no odour elicited a unique response in this population of neurons. However, the proportions of excited, inhibited and insensitive neurons depended significantly on the odour applied, suggesting that the recruitment of olfactory tubercle neurons is directly dependent on the biological significance of the odour.

Role of dog behaviour and environmental fecal contamination in transmission ofEchinococcus multilocularisin Tibetan communities

On the Eastern Tibetan Plateau region (Sichuan province, China) dogs are regarded as important definitive hosts of Echinococcus multilocularis. We studied dog spatial behaviour in 4 Tibetan villages in order to determine the role of dogs in environmental contamination and their potential interactions with small mammal intermediate hosts. We identified definitive host species and Echinococcus spp. infection status of feces collected in the field by PCR methods and analysed the spatial distribution of canid feces. Nocturnal space utilization of GPS collared dogs in and around villages was also undertaken. E. multilocularis DNA was amplified in 23% of dog feces (n=142) and in 15% of fox feces (n=13) but this difference was not significant. However, dog feces were more frequently observed (78% of collected feces) than fox feces and are therefore assumed to largely contribute to human environment contamination. Feces were mainly distributed around houses of dog owners (0-200 m) where collared dogs spent the majority of their time. Inside villages, the contamination was aggregated in some micro-foci where groups of dogs defecated preferentially. Finally, small mammal densities increased from the dog core areas to grasslands at the periphery of villages occasionally used by dogs; male dogs moving significantly farther than females. This study constitutes a first attempt to quantify in a spatially explicit way the role of dogs in E. multilocularis peri-domestic cycles and to identify behavioural parameters required to model E. multilocularis transmission in this region.

FMRI fingerprint of unconditioned fear-like behavior in rats exposed to trimethylthiazoline

Unconditioned fear plays an important yet poorly understood role in anxiety disorders, and only few neuroimaging studies have focused on evaluating the underlying neuronal mechanisms. In rodents the predator odor trimethylthiazoline (TMT), a synthetic component of fox feces, is commonly used to induce states of unconditioned fear. In this study, arterial spin labeling-based functional magnetic resonance imaging (fMRI) was applied to detect TMT-induced regional modulations of neuronal activity in Wistar rats. During TMT exposure the rats displayed increased freezing behavior and reduced exploration in the odor-associated area. Neuronal activity was selectively increased in the dorsal periaqueductal gray, superior colliculus and medial thalamus and reduced in the median raphe, locus coeruleus, nucleus accumbens shell, ventral tegmental area, ventral pallidum and entorhinal piriform cortex. This fMRI fingerprint involving distinct neuronal pathways was used to describe a schematic model of fear processing. Key brain areas known to underlie fear and anxiety-related autonomic and behavioral responses as well as centers of motivational processing were identified as being part of this functional circuitry of innate fear. Thus, preclinical fMRI studies based on unconditioned fear methods may provide a valuable translational approach to better characterize etiological and pathological processes underlying anxiety disorders.