Agents In Animals Research Articles

Infants’ agent individuation: It’s what’s on the insides that counts

Adults and preschool-aged children believe that internal properties are more important than external properties when determining an agent’s identity over time. The current study examined the developmental origins of this understanding using a manual-search individuation task with 13-month-old infants. Subjects observed semi-transparent objects that looked and behaved like animate agents placed into box that they could reach but not see into. Across trials infants observed objects with either the same- or different-colored insides placed into the box. We found that infants used internal property differences more than external property differences to determine how many agents were involved in the event. A second experiment confirmed that this effect was specific to the domain of animate entities. These results suggest that infants are biased to see an agent’s ‘insides’ as more important for determining its identity over time than its outside properties.

Microbubbles containing gadolinium as contrast agents for both phase contrast and magnetic resonance imaging.

Portal vein imaging is an important method for investigating portal venous disorders. However, the diagnostic requirements are not usually satisfied when using single imaging techniques. Diagnostic accuracy can be improved by combining different imaging techniques. Contrast agents that can be used for combined imaging modalities are needed. In this study, the feasibility of using microbubbles containing gadolinium (MCG) as contrast agents for both phase contrast imaging (PCI) and magnetic resonance imaging (MRI) are investigated. MCG were made by encapsulating sulfur hexafluoride (SF6) gas with gadolinium and lyophilized powder. Absorption contrast imaging (ACI) and PCI of MCG were performed and compared in vitro. MCG were injected into the main portal trunk of living rats. PCI and MRI were performed at 2 min and 10 min after MCG injection, respectively. PCI exploited the differences in the refractive index and visibly showed the MCG, which were not detectable by ACI. PCI could facilitate clear revelation of the MCG-infused portal veins. The diameter of the portal veins could be determined by the largest MCG in the same portal vein. The minimum diameter of clearly detected portal veins was about 300 µm by MRI. These results indicate that MCG could enhance both PCI and MRI for imaging portal veins. The detection sensitivity of PCI and MRI could compensate for each other when using MCG contrast agents for animals.

Visually-naïve chicks prefer agents that move as if constrained by a bilateral body-plan

From the first hours of life, the prompt detection of animate agents allows identification of biologically relevant entities. The motion of most animate agents is constrained by their bilaterally-symmetrical body-plan, and consequently tends to be aligned with the main body-axis. Thus parallelism between the main axis of a moving object and its motion trajectory can signal the presence of animate agents. Here we demonstrated that visually-naïve newborn chicks (Gallus gallus domesticus) are attracted to objects displaying such parallelism, and thus show preference for the same type of motion patterns that elicit perception of animacy in humans. This is the first demonstration of a newborn non-human animal’s social preference for a visual cue related to the constraints imposed on behaviour by bilaterian morphology. Chicks also showed preference for rotational movements – a potential manifestation of self-propulsion. Results are discussed in relation to the mechanisms of animacy and agency detection in newborn organisms.

In vitro antimicrobial activity of narasin against common clinical isolates associated with canine otitis externa.

Antimicrobial resistance and antimicrobial stewardship are of ever-increasing importance in veterinary medicine. Re-purposing of old drugs that are not used in human medicine is one approach that addresses the emergence of multidrug resistance in canine skin and ear infections, and can reduce the use of critically important human antibiotic classes. To determine the antimicrobial activity of narasin, a polyether ionophore conventionally used as a rumen modifier and anticoccidial agent in production animals, against common clinical isolates of canine otitis externa (OE). Clinical isolates (n = 110) from canine OE were tested, including 17 meticillin-susceptible Staphylococcus pseudintermedius (MSSP), 13 multidrug-resistant Staphylococcus pseudintermedius (MDRSP), and 20 each of β-haemolytic Streptococcus spp., Pseudomonas aeruginosa, Proteus mirabilis and Malassezia pachydermatis. Bacterial and yeast isolates were subcultured, suspended in broth and inoculated into 96-well plates. Organisms were tested against concentrations of narasin ranging from 0.03 to 128 μg/mL. Minimal inhibitory concentrations (MICs) were determined after overnight incubation. Narasin MICs for staphylococcal and streptococcal isolates ranged from 0.06 to 0.25 μg/mL; MIC50 and MIC90 values for both organisms were 0.125 μg/mL. No MICs were achieved for Pseudomonas or Proteus isolates. There was a weak antifungal effect against M. pachydermatis isolates (MIC 32 to >128 μg/mL). Narasin was effective against Gram-positive bacteria and had antifungal activity at higher concentrations against M. pachydermatis. However, the lack of Gram-negative activity would prevent its use as a sole antimicrobial agent in cases of canine OE.

Consumption of antibacterial molecules in broiler production in Morocco.

Monitoring the use of antibacterial agents in food‐producing animals is crucial in order to reduce antimicrobial resistance, selection and dissemination of resistant bacterial strains, and drug residues in the animal food products. The broiler production sector is considered a great consumer of antibacterials and incriminated in the rise of antimicrobial resistance level in zoonotic bacterial pathogens such as Escherichia coli, Salmonella and Campylobacter. Following recommendations from the OIE and WHO, a survey was conducted about the use and consumption of several antibacterial agents in Moroccan broiler flocks. More than 5 million broilers were randomly surveyed at the prescriber level, that is, via the veterinary clinics involved in their health management. The results showed that 93% of the flocks received at least one antibacterial treatment of minimum 3 days duration. Enrofloxacin, colistin and trimethoprim/sulphonamides were the most used antibacterials followed by oxytetracycline, florfenicol and amoxicillin. Oxytetracycline, enrofloxacin and colistin were overdosed in most of the administration, while amoxicillin and the combination of trimethoprim/sulphonamides were under‐dosed. The total amount of antibacterial consumed in the survey was 63.48 mg/kg and the Animal Level of Exposure to Antimicrobials (ALEA) was 94.45%. The reasons for this frequent use were related mainly to the poor quality of broiler production management. Chicks and animal feed provided to producers were of variable quality. Management of rearing stock density was often poor and biosecurity inadequate, and broilers were challenged by a high prevalence of infectious diseases.

The positive intervention effects of resveratrol on acrylamide -induced cyto-/Genotoxicity in primary lymphocytes of rat

Background: Acrylamide (AA), a product formed from fried foods, has been recognized as a genotoxic agent in animals and humans. Oxidative stress is considered as an indirect cause of AA-related genotoxicity. Objective: Resveratrol (RES) (trans-3,4′,5-trihydroxystilbene) is a natural polyphenol produced by plants such as grapes, berries, and peanuts. In the present work, we studied the potential positive effect of RES in preventing oxidative stress-related cytotoxicity and genotoxicity induced by AA in vitro using rat primary lymphocyte cells. Materials and Methods: The primary lymphocyte cells were induced with AA (5–500 mg/L) for toxicological evaluation and pretreated with RES (100 μM) to determine its protective effect on AA-induced toxicity. The reactive oxygen species (ROS), an inference of oxidative stress, the antioxidant enzyme activity of catalase (CAT), superoxide dismutase (SOD) and glutathione S-transferase (GST) were measured. In addition, the micronucleus (MN) and nuclear fragmentation were analyzed by confocal microscopy to study the protective role of RES on AA-induced genotoxicity. Results: The cells pretreated with RES at a concentration of 100 μM for 24 h protected against AA-induced cytotoxicity, caused a reduction in ROS, showed an elevation in the activity of CAT, SOD, and GST signifying an increase in antioxidant function. Furthermore, the genotoxic effects of DNA damage, MN and nuclear fragmentation induced by AA were reduced on RES preexposure, thus showing the protective effect. Conclusion: Thus, our results suggested that RES effectively protected primary lymphocytes from AA-induced genotoxicity probably through reduction of ROS and increased antioxidant function. Abbreviations Used: AA: Acrylamide; RES: Resveratrol; ROS: Reactive oxygen species; SOD: Superoxide dismutase; GST: Glutathione S-transferase; MN: Micronucleus; CAT: Catalase.

Exceptionalist naturalism: Human agency and the causal order.

This paper addresses a fundamental question in folk metaphysics: How do we ordinarily view human agency? According to the transcendence account, we view human agency as standing outside of the causal order and imbued with exceptional powers. According to a naturalistic account, we view human agency as subject to the same physical laws as other objects and completely open to scientific investigation. According to exceptionalist naturalism, the truth lies somewhere in between: We view human agency as fitting broadly within the causal order while still being exceptional in important respects. In this paper, I report seven experiments designed to decide between these three competing theories. Across a variety of contexts and types of action, participants agreed that human agents can resist outcomes described as inevitable, guaranteed, and causally determined. Participants viewed non-human animal agents similarly, whereas they viewed computers, robots, and simple inanimate objects differently. At the same time, participants judged that human actions are caused by many things, including psychological, neurological, and social events. Overall, in folk metaphysics, human and non-human animals are viewed as exceptional parts of the natural world.

Vegetative compatibility and phenotypic characterization as a means of determining genetic diversity of Aspergillus flavus isolates

Toxigenic Aspergillus species produce mycotoxins that are carcinogenic, hepatotoxic and teratogenic immunosuppressing agents in both human and animals. Kenya frequently experiences outbreaks of aflatoxicosis with the worst occurring in 2010, which resulted in 215 deaths. We examined the possible reasons for these frequent aflatoxicosis outbreaks in Kenya by studying Aspergillus flavus diversity, phenotypes and mycotoxin profiles across various agricultural regions. Using diagonal transect random sampling, maize kernels were collected from Makueni, Homa Bay, Nandi, and Kisumu counties. Out of 37 isolates, nitrate non-utilizing auxotrophs complementation test revealed 20 vegetative compatibility groups. We designated these groups by the prefix “KVCG”, where “K” represented Kenya and consequently assigned numbers 1–20 based on our findings. KVCG14 and KVCG15 had highest distribution frequency (n = 13; 10.8 %). The distribution of the L-, S- and S-/L-morphotypes across the regions were 57 % (n = 21); 7 % (n = 3) and 36 % (n = 13), respectively. Furthermore, a unique isolate (KSM015) was identified that had characteristics of S-morphotype, but produced both aflatoxins B and G. Coconut agar medium (CAM) assay, TLC and HPLC analyses confirmed the presence or absence of aflatoxins in selected toxigenic and atoxigenic isolates. Diversity index (H′) analyses ranged from 0.11 (Nandi samples) to 0.32 (Kisumu samples). Heterokaryon compatibility ranged from 33 % (for the Makueni samples, n = 3) to 67 % (Nandi samples, n = 6). To our knowledge, this is the first reported findings for A. flavus diversity and distribution in Nandi, Homa Bay and Kisumu counties and may assist current and future researchers in the selection of biocontrol strategies to mitigate aflatoxin contamination as has been researched in Makueni and neighbouring counties.

Whole body physiologically based modelling of β-blockers in the rat: events in tissues and plasma following an i.v. bolus dose.

Whole body physiologically based pharmacokinetic (PBPK) models have been increasingly applied in drug development to describe kinetic events of therapeutic agents in animals and humans. The advantage of such modelling is the ability to incorporate vast amounts of physiological information, such as organ blood flow and volume, to ensure that the model is as close to reality as possible. Previous PBPK model development of enantiomers of a series of seven racemic β-blockers, namely, acebutolol, betaxolol, bisoprolol, metoprolol, oxprenolol, pindolol and propranolol, together with S-timolol in rat was based on tissue and blood concentration data at steady state. Compounds were administered in several cassettes with the composition mix and blood and tissue sampling times determined using a D-optimal design. Closed-loop PBPK models were developed initially based on the application of open loop forcing function models to individual tissues and compounds. For the majority of compounds and tissues, distribution kinetics was adequately characterized by perfusion rate-limited models. For some compounds in the testes and gut, a permeability rate-limited distribution model was required to best fit the data. Parameter estimates of the tissue-to-blood partition coefficient through fitting of individual enantiomers and of racemic pair were generally in agreement and also concur with those from previous steady-state experiments. PBPK modelling is a very powerful tool to aid drug discovery and development of therapeutic agents in animals and humans. However, careful consideration of the assumptions made during the modelling exercise is essential.

Self-medication by orang-utans (Pongo pygmaeus) using bioactive properties of Dracaena cantleyi

Animals self-medicate using a variety of plant and arthropod secondary metabolites by either ingesting them or anointing them to their fur or skin apparently to repel ectoparasites and treat skin diseases. In this respect, much attention has been focused on primates. Direct evidence for self-medication among the great apes has been limited to Africa. Here we document self-medication in the only Asian great ape, orang-utans (Pongo pygmaeus), and for the first time, to our knowledge, the external application of an anti-inflammatory agent in animals. The use of leaf extracts from Dracaena cantleyi by orang-utan has been observed on several occasions; rubbing a foamy mixture of saliva and leaf onto specific parts of the body. Interestingly, the local indigenous human population also use a poultice of these leaves for the relief of body pains. We present pharmacological analyses of the leaf extracts from this species, showing that they inhibit TNFα-induced inflammatory cytokine production (E-selectin, ICAM-1, VCAM-1 and IL-6). This validates the topical anti-inflammatory properties of this plant and provides a possible function for its use by orang-utans. This is the first evidence for the deliberate external application of substances with demonstrated bioactive potential for self-medication in great apes.

Microbial agents in macroscopically healthy mammary gland tissues of small ruminants.

BackgroundHealth of mammary glands is fundamental for milk and dairy products hygiene and quality, with huge impacts on consumers welfare.MethodsThis study aims to investigate the microbial agents (bacteria, fungi and lentiviruses) isolated from 89 macroscopically healthy udders of regularly slaughtered small ruminants (41 sheep, 48 goats), also correlating their presence with the histological findings. Multinomial logistic regression was applied to evaluate the association between lesions and positivity for different microbial isolates, animal age and bacteria.ResultsTwenty-five samples were microbiologically negative; 138 different bacteria were isolated in 64 positive udders. Coagulase-negative staphylococci were the most prevalent bacteria isolated (46.42%), followed by environmental opportunists (34.76%), others (10.14%) and pathogens (8.68%). Most mammary glands showed coinfections (75%). Lentiviruses were detected in 39.3% of samples. Histologically, chronic non-suppurative mastitis was observed in 45/89 glands, followed by chronic mixed mastitis (12/89) and acute suppurative mastitis (4/89). Only 28 udders were normal. Histological lesions were significantly associated with the animal species and lentiviruses and coagulase-negative staphylococci infections. Goats had significantly higher risk to show chronic mixed mastitis compared to sheep. Goats showed a significantly lower risk (OR = 0.26; 95% CI [0.06–0.71]) of being infected by environmental opportunists compared to sheep, but higher risk (OR = 10.87; 95% CI [3.69–37.77]) of being infected with lentiviruses.DiscussionThe results of the present study suggest that macroscopically healthy glands of small ruminants could act as a reservoir of microbial agents for susceptible animals, representing a potential risk factor for the widespread of acute or chronic infection in the flock.

When Cars Hit Trucks and Girls Hug Boys: The Effect of Animacy on Word Order in Gestural Language Creation.

A well-known typological observation is the dominance of subject-initial word orders, SOV and SVO, across the world's languages. Recent findings from gestural language creation paradigms offer possible explanations for the prevalence of SOV. When asked to gesture transitive events with an animate agent and inanimate patient, gesturers tend to produce SOV order, regardless of their native language biases. Interestingly, when the patient is animate, gesturers shift away from SOV to use of other orders, like SVO and OSV. Two competing hypotheses have been proposed for this switch: the noisy channel account (Gibson etal., 2013) and the role conflict account (Hall, Mayberry, & Ferreira, 2013). We set out to distinguish between these two hypotheses, disentangling event reversibility and patient animacy, by looking at gestural sequences for events with two inanimate participants (inanimate-inanimate, reversible). We replicated the previous findings of a preference for SOV order when describing animate-inanimate, irreversible events as well as a decrease in the use of SOV when presented with animate-animate, reversible events. Accompanying the drop in SOV, in a novel condition we observed an increase in the use of SVO and OSV orders when describing events involving two animate entities. In sum, we find that the observed avoidance of SOV order in gestural language creation paradigms when the event includes an animate agent and patient is driven by the animacy of the participants rather than the reversibility of the event. We suggest that findings from gestural creation paradigms are not automatically linkable to spoken language typology.

Perceiving social interactions in the posterior superior temporal sulcus

Primates are highly attuned not just to social characteristics of individual agents, but also to social interactions between multiple agents. Here we report a neural correlate of the representation of social interactions in the human brain. Specifically, we observe a strong univariate response in the posterior superior temporal sulcus (pSTS) to stimuli depicting social interactions between two agents, compared with (i) pairs of agents not interacting with each other, (ii) physical interactions between inanimate objects, and (iii) individual animate agents pursuing goals and interacting with inanimate objects. We further show that this region contains information about the nature of the social interaction-specifically, whether one agent is helping or hindering the other. This sensitivity to social interactions is strongest in a specific subregion of the pSTS but extends to a lesser extent into nearby regions previously implicated in theory of mind and dynamic face perception. This sensitivity to the presence and nature of social interactions is not easily explainable in terms of low-level visual features, attention, or the animacy, actions, or goals of individual agents. This region may underlie our ability to understand the structure of our social world and navigate within it.

Closing the gap between Aboriginal and non-Aboriginal health workers through story telling

Non-thermal plasma has been used in many medical applications, including treatment of living cells, blood coagulation, wound healing, and sterilization. The process uses an environmentally friendly gas (e.g., argon, helium, oxygen, nitrogen, or hydrogen) to destroy bacteria cells with no serious adverse effect on humans or animals. However, information on the effect of argon plasma on blow fly eggs is lacking. In this study, we explored the ability of cold argon plasma to destroy the eggs of the Australian sheep blow fly, Lucilia cuprina (Wiedemann, 1830); its larvae are a myiasis-producing agent in both human and animals. We tested the effect of cold argon plasma exposure for 1, 2, 3 and 5 min on L. cuprina eggs. Since the temperature of cold Ar plasma is around 30 °C, to clarify the effect of temperature on the fly eggs, hot air from an electric dryer was tested for comparison. Cold argon plasma exposure in eggs significantly reduced the survival rates of second instar larvae at all exposures tested; the effects were time dependent, with a stronger effect at longer exposure (32% survival rate after a 1-min treatment; 20%, 2 min; 20%, 3 min; and 6%, 5 min), compared to the control (86%). No significant differences were observed in larval survival rates from eggs treated with hot air (80-84%, after 1- to 5-min treatments) versus the control (86%). These results were supported by observing the treated eggshells under a scanning electron microscope (SEM), we found noticeable aberrations only in the plasma treated groups. The emission spectrum of the argon gas discharge revealed emission lines of hydroxyl radicals at 309.1 nm; these may cause the deterioration of the treated L. cuprina eggs. Our results have shown the possibility of using cold argon plasma in medical applications, in particular treating myiasis wounds.

Psyllium Husk (Plantago ovata) as a Potent Hypocholesterolemic Agent in Animal, Human and Poultry

Psyllium Husk (Plantago ovata) as a Potent Hypocholesterolemic Agent in Animal, Human and Poultry

Effect of cold argon plasma on eggs of the blow fly, Lucilia cuprina (Diptera: Calliphoridae)

Non-thermal plasma has been used in many medical applications, including treatment of living cells, blood coagulation, wound healing, and sterilization. The process uses an environmentally friendly gas (e.g., argon, helium, oxygen, nitrogen, or hydrogen) to destroy bacteria cells with no serious adverse effect on humans or animals. However, information on the effect of argon plasma on blow fly eggs is lacking. In this study, we explored the ability of cold argon plasma to destroy the eggs of the Australian sheep blow fly, Lucilia cuprina (Wiedemann, 1830); its larvae are a myiasis-producing agent in both human and animals. We tested the effect of cold argon plasma exposure for 1, 2, 3 and 5min on L. cuprina eggs. Since the temperature of cold Ar plasma is around 30°C, to clarify the effect of temperature on the fly eggs, hot air from an electric dryer was tested for comparison. Cold argon plasma exposure in eggs significantly reduced the survival rates of second instar larvae at all exposures tested; the effects were time dependent, with a stronger effect at longer exposure (32% survival rate after a 1-min treatment; 20%, 2min; 20%, 3min; and 6%, 5min), compared to the control (86%). No significant differences were observed in larval survival rates from eggs treated with hot air (80-84%, after 1- to 5-min treatments) versus the control (86%). These results were supported by observing the treated eggshells under a scanning electron microscope (SEM), we found noticeable aberrations only in the plasma treated groups. The emission spectrum of the argon gas discharge revealed emission lines of hydroxyl radicals at 309.1nm; these may cause the deterioration of the treated L. cuprina eggs. Our results have shown the possibility of using cold argon plasma in medical applications, in particular treating myiasis wounds.

Antioxidant potential, anti-inflammatory activity and gastroprotective mechanisms of Mallotus roxburghianus (Muell.) against ethanol-induced gastric ulcers in Wistar albino rats

Mallotus roxburghianus (MR) is being employed as a dietary supplement and therapeutic agent to treat inflammation and stomach ulcers in Southeast Asia. Gastroprotective effects of methanol leaf extract of MR (MRME) and its possible mechanisms were elucidated in ethanol induced gastric ulcers in Wistar albino rats. MRME was abundant with polyphenols (bergenin and betulinic acid) as well as antioxidant and anti-inflammatory activities as evidenced by low IC50 values. Significant (p<0.05) enhancement in gastric tissue injuries, histopathological alterations, higher infiltration of eosinophils and mast cells, increase in pH, total acidity and malonaldehyde levels, reduction in mucus content and antioxidant defense enzymes and down regulation of HSP70 expression were noticed in ulcer control group while these pathological manifestations were significantly recuperated by pretreatment of MRME in the doses between 5 and 200mg/kg. Based on these findings, MRME could be used as a new source of gastroprotective therapeutic agent in animals.

Antiepileptogenic and Neuroprotective Effects of Pergularia daemia on Pilocarpine Model of Epilepsy.

In this study, we investigated antiepileptogenic and neuroprotective effects of the aqueous extract of Pergularia daemia roots (PDR) using in vivo and in vitro experimental models. In in vivo studies, status epilepticus caused by pilocarpine injection triggers epileptogenesis which evolves during about 1–2 weeks. After 2 h of status epilepticus, mice were treated during the epileptogenesis period for 7 days with sodium valproate and vitamin C (standards which demonstrated to alter epileptogenesis), or Pergularia daemia. The animals were then, 1 week after status epilepticus, challenged with acute pentylenetetrazole (PTZ) administration to test behaviorally the susceptibility to a convulsant agent of animals treated or not with the plan extract. Memory was assessed after PTZ administration in the elevated plus maze and T-maze paradigms at 24 and 48 h. Antioxidant and acetylcholinesterase activities were determined in the hippocampus after sacrifice, in vitro studies were conducted using embryonic rat primary cortical cultures exposed to L-glutamate. Cell survival rate was measured and apoptotic and necrotic cell death determined. The results showed that chronic oral administration of PDR significantly and dose-dependently increased the latency to myoclonic jerks, clonic seizures and generalized tonic–clonic seizures, and the seizure score. In addition, PDR at all doses (from 4.9 to 49 mg/kg) significantly decreased the initial and retention transfer latencies in the elevated plus maze. Interestingly PDR at the same doses significantly increased the time spent and the number of entries in T-maze novel arm. PDR significantly increased the activities of acetylcholinesterase and antioxidant enzymes superoxide dismutase, catalase, and total glutathione and proteins, and decreased malondialdehyde level. Furthermore, PDR increased viability rate of primary cortical neurons after L-glutamate-induced excitotoxicity, in a dose dependent manner. Altogether these results suggest that PDR has antiepileptogenic and neuroprotective effects, which could be mediated by antioxidant and antiapoptotic activities.

MOLECULAR DETECTION OF INFECTIOUS PATHOGENS OF THE UPPER RESPIRATORY TRACT IN CAPTIVE NONDOMESTIC FELIDS.

Upper respiratory tract disease is a complex infectious disease process with multiple pathogens involved. Identification of infectious agents in wild animals is of great importance for wildlife conservation. The aim of this study was to evaluate the molecular detection of feline herpesvirus type 1, feline calicivirus (FCV), Bordetella bronchiseptica , Chlamydophila felis , and Mycoplasma felis using ocular and nasal swabs in three species of captive nondomestic felids. Mycoplasma felis was detected in two ocular samples of Puma concolor and in one nasal sample of one Panthera onca . FCV was detected in association with M. felis in one P. concolor . The other pathogens tested were not detected. To the authors' knowledge, this is the first report of M. felis in nondomestic felids from Brazil.

Pathogenic Leptospira spp. in bats: Molecular investigation in Southern Brazil.

The present study aimed to investigate the frequency of pathogenic Leptospira spp. in Brazilian bats and to determine possible risk factors associated to it. Ninety two bats of 12 species were evaluated. Whole genomic DNA from kidneys was extracted and real-time PCR specific to pathogenic Leptospira spp. was applied. Association between the frequency of specimens positive for Leptospira spp. and sex, age, bat species or family, season of collection, geographic localization and feeding habits was evaluated. The results showed that 39.13% of analyzed bats were found positive for Leptospira spp. Nine bat species had at least one positive result. There was no association among the evaluated variables and frequency of pathogenic Leptospira spp. Although the limitations due to lack of Leptospira spp. isolation, leptospiral carriage was demonstrated in bats of different species from southern Brazil, which reinforces the need for surveillance of infectious agents in wild animals.