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A D Davis - One of the best experts on this subject based on the ideXlab platform.

  • unique characteristics of bat rabies viruses in big brown bats Eptesicus fuscus
    Archives of Virology, 2013
    Co-Authors: Paul A Gordy, A D Davis, R A Bowen
    Abstract:

    Rabies virus infection has been documented in several North American bat species, including Eptesicus fuscus. The virus-host relationship between bats and rabies virus (RV) is not well understood. The incidence of non-lethal RV exposure, based on the presence of viral neutralizing antibodies, demonstrates that exposure to RV does not always lead to clinical infection in bats. It is unknown how the route of exposure, rabies virus variant, or health of the bat affects the outcome following exposure. This paper describes the pathogenesis of two big brown bat RV variants in homologous host species. Our study demonstrates that RV variants obtained from the same species of bat from similar geographical areas may result in a diverse clinical progression of disease.

  • extended incubation period of rabies virus in a captive big brown bat Eptesicus fuscus
    Journal of Wildlife Diseases, 2012
    Co-Authors: A D Davis, Michelle Dupuis, Robert J Rudd
    Abstract:

    Rabies virus incubation in bats is typically less than 180 days, yet longer incubation periods have been described. We report a 267-day incubation in a big brown bat (Eptesicus fuscus) exposed to rabies virus before entering our captive colony.

  • rabies in a captive colony of big brown bats Eptesicus fuscus
    Journal of Wildlife Diseases, 2004
    Co-Authors: R A Bowen, A D Davis, V. Shankar, Charles E. Rupprecht, Thomas J Oshea
    Abstract:

    Our research has focused on the ecology of commensal populations of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado (USA), in relation to rabies virus (RV) transmission. We captured 35 big brown bats (Eptesicus fuscus) in late summer 2001 and held them captive for 4.8 mo. The bats were initially placed in an indoor cage for 1 mo then segregated into groups of two to six per cage. Two of the bats succumbed to rabies virus (RV) within the first month of capture. Despite group housing, all of the remaining bats were healthy over the course of the investigation; none developed rabies, although one of the rabid bats was observed to bite her cage mates. Reverse transcription–polymerase chain reaction (RT-PCR) and Taqman® real-time PCR analysis of the RNA derived from the brain tissue, salivary glands, and oral swab samples confirmed RV infection in the dead bats. Rabies virus was also isolated from the brain tissue upon passage in mouse neuroblastoma cells. Nucleotide sequence analysis of the RV nuc...

  • Rabies in a captive colony of big brown bats (Eptesicus fuscus)
    Journal of Wildlife Diseases, 2004
    Co-Authors: V. Shankar, R A Bowen, A D Davis, Charles E. Rupprecht, T.j. Shea
    Abstract:

    Our research has focused on the ecology of commensal populations of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado (USA), in relation to rabies virus (RV) transmission. We captured 35 big brown bats (Eptesicus fuscus) in late summer 2001 and held them captive for 4.8 mo. The bats were initially placed in an indoor cage for 1 mo then segregated into groups of two to six per cage. Two of the bats succumbed to rabies virus (RV) within the first month of capture. Despite group housing, all of the remaining bats were healthy over the course of the investigation; none developed rabies, although one of the rabid bats was observed to bite her cage mates. Reverse transcription-polymerase chain reaction (RT-PCR) and Taqman(R) real-time PCR analysis of the RNA derived from the brain tissue, salivary glands, and oral swab samples confirmed RV infection in the dead bats. Rabies virus was also isolated from the brain tissue upon passage in mouse neuroblastoma cells. Nucleotid! e sequence analysis of the RV nucleoprotein (N) gene showed 100% identity with the N gene sequence of a 1985 E. fuscus isolate from El Paso County, Colorado. Bat sera obtained six times throughout the study were assayed for RV neutralizing antibodies using the rapid fluorescent focus inhibition test. The RV neutralizing activity in the serum was associated with the IgG component, which was purified by binding to protein G Sepharose. Five bats were RV seropositive prior to their capture and maintained titers throughout captivity. Two adult bats seroconverted during captivity. Two volant juvenile bats had detectable RV antibody titers at the first serum collection but were negative thereafter. Four seronegative bats responded to a RV vaccine administration with high titers of RV antibodies. A serologic survey of big brown bats in the roost from which one of the captive rabid bats had originated showed a significant rise in seroprevalence during 2002

R A Bowen - One of the best experts on this subject based on the ideXlab platform.

  • unique characteristics of bat rabies viruses in big brown bats Eptesicus fuscus
    Archives of Virology, 2013
    Co-Authors: Paul A Gordy, A D Davis, R A Bowen
    Abstract:

    Rabies virus infection has been documented in several North American bat species, including Eptesicus fuscus. The virus-host relationship between bats and rabies virus (RV) is not well understood. The incidence of non-lethal RV exposure, based on the presence of viral neutralizing antibodies, demonstrates that exposure to RV does not always lead to clinical infection in bats. It is unknown how the route of exposure, rabies virus variant, or health of the bat affects the outcome following exposure. This paper describes the pathogenesis of two big brown bat RV variants in homologous host species. Our study demonstrates that RV variants obtained from the same species of bat from similar geographical areas may result in a diverse clinical progression of disease.

  • factors influencing movement probabilities of big brown bats Eptesicus fuscus in buildings
    Ecological Applications, 2007
    Co-Authors: Laura E Ellison, Daniel J Neubaum, Thomas J Oshea, R A Bowen
    Abstract:

    We investigated movements of female big brown bats (Eptesicus fuscus) roosting in maternity colonies in buildings in Fort Collins, Colorado (USA), during the summers of 2002, 2003, and 2005. This behavior can be of public health concern where bats that may carry diseases (e.g., rabies) move among buildings occupied by people. We used passive integrated transponders (PIT tags) to mark individual bats and hoop PIT readers at emergence points to passively monitor the use of building roosts by marked adult females on a daily basis during the lactation phase of reproduction. Multi-strata models were used to examine movements among roosts in relation to ambient temperatures and ectoparasite loads. Our results suggest that high ambient temperatures influence movements. Numbers of mites (Steatonyssus occidentalis) did not appear to influence movements of female bats among building roosts. In an urban landscape, periods with unusually hot conditions are accompanied by shifting of bats to different buildings or segments of buildings, and this behavior may increase the potential for contact with people in settings where, in comparison to their more regularly used buildings, the bats may be more likely to be of public concern as nuisances or health risks.

  • rabies in a captive colony of big brown bats Eptesicus fuscus
    Journal of Wildlife Diseases, 2004
    Co-Authors: R A Bowen, A D Davis, V. Shankar, Charles E. Rupprecht, Thomas J Oshea
    Abstract:

    Our research has focused on the ecology of commensal populations of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado (USA), in relation to rabies virus (RV) transmission. We captured 35 big brown bats (Eptesicus fuscus) in late summer 2001 and held them captive for 4.8 mo. The bats were initially placed in an indoor cage for 1 mo then segregated into groups of two to six per cage. Two of the bats succumbed to rabies virus (RV) within the first month of capture. Despite group housing, all of the remaining bats were healthy over the course of the investigation; none developed rabies, although one of the rabid bats was observed to bite her cage mates. Reverse transcription–polymerase chain reaction (RT-PCR) and Taqman® real-time PCR analysis of the RNA derived from the brain tissue, salivary glands, and oral swab samples confirmed RV infection in the dead bats. Rabies virus was also isolated from the brain tissue upon passage in mouse neuroblastoma cells. Nucleotide sequence analysis of the RV nuc...

  • Rabies in a captive colony of big brown bats (Eptesicus fuscus)
    Journal of Wildlife Diseases, 2004
    Co-Authors: V. Shankar, R A Bowen, A D Davis, Charles E. Rupprecht, T.j. Shea
    Abstract:

    Our research has focused on the ecology of commensal populations of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado (USA), in relation to rabies virus (RV) transmission. We captured 35 big brown bats (Eptesicus fuscus) in late summer 2001 and held them captive for 4.8 mo. The bats were initially placed in an indoor cage for 1 mo then segregated into groups of two to six per cage. Two of the bats succumbed to rabies virus (RV) within the first month of capture. Despite group housing, all of the remaining bats were healthy over the course of the investigation; none developed rabies, although one of the rabid bats was observed to bite her cage mates. Reverse transcription-polymerase chain reaction (RT-PCR) and Taqman(R) real-time PCR analysis of the RNA derived from the brain tissue, salivary glands, and oral swab samples confirmed RV infection in the dead bats. Rabies virus was also isolated from the brain tissue upon passage in mouse neuroblastoma cells. Nucleotid! e sequence analysis of the RV nucleoprotein (N) gene showed 100% identity with the N gene sequence of a 1985 E. fuscus isolate from El Paso County, Colorado. Bat sera obtained six times throughout the study were assayed for RV neutralizing antibodies using the rapid fluorescent focus inhibition test. The RV neutralizing activity in the serum was associated with the IgG component, which was purified by binding to protein G Sepharose. Five bats were RV seropositive prior to their capture and maintained titers throughout captivity. Two adult bats seroconverted during captivity. Two volant juvenile bats had detectable RV antibody titers at the first serum collection but were negative thereafter. Four seronegative bats responded to a RV vaccine administration with high titers of RV antibodies. A serologic survey of big brown bats in the roost from which one of the captive rabid bats had originated showed a significant rise in seroprevalence during 2002

Cynthia F. Moss - One of the best experts on this subject based on the ideXlab platform.

  • age dependent gene expression in the inner ear of big brown bats Eptesicus fuscus
    PLOS ONE, 2017
    Co-Authors: Cynthia F. Moss, Gerald S. Wilkinson
    Abstract:

    : For echolocating bats, hearing is essential for survival. Specializations for detecting and processing high frequency sounds are apparent throughout their auditory systems. Recent studies on echolocating mammals have reported evidence of parallel evolution in some hearing-related genes in which distantly related groups of echolocating animals (bats and toothed whales), cluster together in gene trees due to apparent amino acid convergence. However, molecular adaptations can occur not only in coding sequences, but also in the regulation of gene expression. The aim of this study was to examine the expression of hearing-related genes in the inner ear of developing big brown bats, Eptesicus fuscus, during the period in which echolocation vocalizations increase dramatically in frequency. We found that seven genes were significantly upregulated in juveniles relative to adults, and that the expression of four genes through development correlated with estimated age. Compared to available data for mice, it appears that expression of some hearing genes is extended in juvenile bats. These results are consistent with a prolonged growth period required to develop larger cochlea relative to body size, a later maturation of high frequency hearing, and a greater dependence on high frequency hearing in echolocating bats.

  • Signature calls predict foraging success in big brown bats (Eptesicus fuscus)
    Journal of the Acoustical Society of America, 2015
    Co-Authors: Genevieve Spanjer Wright, Chen Chiu, Wei Xian, Gerald S. Wilkinson, Cynthia F. Moss
    Abstract:

    Animals foraging in the dark must simultaneously pursue prey, avoid collisions, and interact with conspecifics, making efficient non-visual communication essential. A variety of birds and mammals emit food-associated calls that inform, attract, or repel conspecifics. While echolocation by the insectivorous, aerial-hawking big brown bat (Eptesicus fuscus) has been studied extensively, communicative calls used by this species have received comparatively little research attention. We report on a rich repertoire of vocalizations produced by big brown bats in a large flight room equipped with synchronized high-speed stereo video and audio recording equipment. We also provide evidence that a specific social call, the “frequency-modulated bout” (FMB), which is emitted only by males, exclusively in a foraging context, and only when conspecifics are present, predicts the caller’s foraging success and is individually distinct. Bats were studied individually and in pairs, while sex and experience with a foraging tas...

  • social calls of flying big brown bats Eptesicus fuscus
    Frontiers in Physiology, 2013
    Co-Authors: Genevieve Spanjer Wright, Chen Chiu, Wei Xian, Gerald S. Wilkinson, Cynthia F. Moss
    Abstract:

    Vocalizations serving a variety of social functions have been reported in many bat species (Order Chiroptera). While echolocation by big brown bats (Eptesicus fuscus) has been the subject of extensive study, calls used by this species for communication have received comparatively little research attention. Here, we report on a rich repertoire of vocalizations produced by big brown bats in a large flight room equipped with synchronized high speed stereo video and audio recording equipment. Bats were studied individually and in pairs, while sex, age, and experience with a novel foraging task were varied. We used Discriminant Function Analysis to classify six different vocalizations that were recorded when two bats were present. Contingency table analyses revealed a higher prevalence of social calls when males were present, and some call types varied in frequency of emission based on trial type or bat age. Bats flew closer together around the time some social calls were emitted, indicating that communicative calls may be selectively produced when conspecifics fly near one another. These findings are the first reports of social calls from flying big brown bats and provide insight into the function of communicative vocalizations emitted by this species.

  • Audiomotor integration for active sensing in the echolocating bat, Eptesicus fuscus
    Journal of the Acoustical Society of America, 2002
    Co-Authors: Cynthia F. Moss, Shiva R. Sinha, Kaushik Ghose
    Abstract:

    Echolocating bats probe the environment with sonar signals that change as they seek, pursue and intercept insect prey on the wing. Coordinating its sonar vocalizations with flight dynamics in response to changing echo information, the bat exhibits a dazzling display of sensorimotor integration. Our work aims at understanding the mechanisms supporting audiomotor integration for echolocation in the FM‐bat, Eptesicus fuscus. Behavioral studies measure adaptive responses of free‐flying bats engaged in complex spatial tasks. The directional aim of the bat’s sonar beam and temporal patterning of cries provide explicit data on the motor commands that feed directly back to the auditory system for spatially‐guided behavior. Neural studies focus on the superior colliculus (SC), a midbrain structure implicated in species‐specific orienting behaviors. A population of SC neurons shows echo‐delay tuning, a response property believed to play a role in target range coding. Microstimulation of the SC elicits head and pinn...

  • echolocation behavior of big brown bats Eptesicus fuscus in the field and the laboratory
    Journal of the Acoustical Society of America, 2000
    Co-Authors: Annemarie Surlykke, Cynthia F. Moss
    Abstract:

    Echolocation signals were recorded from big brown bats, Eptesicus fuscus, flying in the field and the laboratory. In open field areas the interpulse intervals (IPI) of search signals were either around 134 ms or twice that value, 270 ms. At long IPI’s the signals were of long duration (14 to 18–20 ms), narrow bandwidth, and low frequency, sweeping down to a minimum frequency (Fmin) of 22–25 kHz. At short IPI’s the signals were shorter (6–13 ms), of higher frequency, and broader bandwidth. In wooded areas only short (6–11 ms) relatively broadband search signals were emitted at a higher rate (avg. IPI=122 ms) with higher Fmin (27–30 kHz). In the laboratory the IPI was even shorter (88 ms), the duration was 3–5 ms, and the Fmin 30–35 kHz, resembling approach phase signals of field recordings. Excluding terminal phase signals, all signals from all areas showed a negative correlation between signal duration and Fmin, i.e., the shorter the signal, the higher was Fmin. This correlation was reversed in the termin...

Thomas J Oshea - One of the best experts on this subject based on the ideXlab platform.

  • ectoparasites in an urban population of big brown bats Eptesicus fuscus in colorado
    Journal of Parasitology, 2007
    Co-Authors: Roger D Pearce, Thomas J Oshea
    Abstract:

    Ectoparasites of an urban population of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado, were investigated during summers 2002, 2003, and 2004. Eleven species of ectoparasites were found (the macronyssid mite Steatonyssus occidentalis, the wing mite Spinturnix bakeri, the myobiid mites Acanthophthirius caudata and Pteracarus aculeus, the chirodiscid mite Alabidocarpus Eptesicus, the demodicid mite Demodex sp., the chigger Leptotrombidium myotis, the soft tick Carios kelleyi, the batfly Basilia forcipata, the batbug Cimex pilosellus, and the flea Myodopsylla borealis). Five species were analyzed by prevalence and intensity (C. pilosellus, M. borealis, L. myotis, S. bakeri, and S. occidentalis) based on 2,161 counts of 1,702 marked individual bats over the 3 summer study periods. We investigated 4 factors potentially influencing prevalence and intensity: age class of the host, reproductive status of adult female hosts, roosts in which the hosts were found, and abiotic conditions during the year ...

  • factors influencing movement probabilities of big brown bats Eptesicus fuscus in buildings
    Ecological Applications, 2007
    Co-Authors: Laura E Ellison, Daniel J Neubaum, Thomas J Oshea, R A Bowen
    Abstract:

    We investigated movements of female big brown bats (Eptesicus fuscus) roosting in maternity colonies in buildings in Fort Collins, Colorado (USA), during the summers of 2002, 2003, and 2005. This behavior can be of public health concern where bats that may carry diseases (e.g., rabies) move among buildings occupied by people. We used passive integrated transponders (PIT tags) to mark individual bats and hoop PIT readers at emergence points to passively monitor the use of building roosts by marked adult females on a daily basis during the lactation phase of reproduction. Multi-strata models were used to examine movements among roosts in relation to ambient temperatures and ectoparasite loads. Our results suggest that high ambient temperatures influence movements. Numbers of mites (Steatonyssus occidentalis) did not appear to influence movements of female bats among building roosts. In an urban landscape, periods with unusually hot conditions are accompanied by shifting of bats to different buildings or segments of buildings, and this behavior may increase the potential for contact with people in settings where, in comparison to their more regularly used buildings, the bats may be more likely to be of public concern as nuisances or health risks.

  • survival and condition of big brown bats Eptesicus fuscus after radiotagging
    Journal of Mammalogy, 2005
    Co-Authors: Daniel J Neubaum, Melissa A Neubaum, Laura E Ellison, Thomas J Oshea
    Abstract:

    We tested the 5% rule for the ratio of radiotransmitter mass to body mass by applying radiotransmitters and passive integrated transponders (PIT tags) or PIT tags alone to adult, female big brown bats (Eptesicus fuscus) roosting in buildings in Fort Collins, Colorado. We used records from PIT readers at roosts to compute apparent annual survival of both groups from 2001 to 2003 and found them to be similar. All bats examined 1 year after radiotagging were reproductively active and had body masses similar to bats not radiotagged. Big brown bats do not appear to suffer from major long-term effects of carrying transmitters within the 5% rule.

  • rabies in a captive colony of big brown bats Eptesicus fuscus
    Journal of Wildlife Diseases, 2004
    Co-Authors: R A Bowen, A D Davis, V. Shankar, Charles E. Rupprecht, Thomas J Oshea
    Abstract:

    Our research has focused on the ecology of commensal populations of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado (USA), in relation to rabies virus (RV) transmission. We captured 35 big brown bats (Eptesicus fuscus) in late summer 2001 and held them captive for 4.8 mo. The bats were initially placed in an indoor cage for 1 mo then segregated into groups of two to six per cage. Two of the bats succumbed to rabies virus (RV) within the first month of capture. Despite group housing, all of the remaining bats were healthy over the course of the investigation; none developed rabies, although one of the rabid bats was observed to bite her cage mates. Reverse transcription–polymerase chain reaction (RT-PCR) and Taqman® real-time PCR analysis of the RNA derived from the brain tissue, salivary glands, and oral swab samples confirmed RV infection in the dead bats. Rabies virus was also isolated from the brain tissue upon passage in mouse neuroblastoma cells. Nucleotide sequence analysis of the RV nuc...

James A. Simmons - One of the best experts on this subject based on the ideXlab platform.

  • big brown bats Eptesicus fuscus maintain hearing sensitivity after exposure to intense band limited noise
    Journal of the Acoustical Society of America, 2017
    Co-Authors: Andrea Megela Simmons, James A. Simmons
    Abstract:

    Thresholds to short-duration narrowband frequency-modulated (FM) sweeps were measured in six big brown bats (Eptesicus fuscus) in a two-alternative forced choice passive listening task before and after exposure to band-limited noise (lower and upper frequencies between 10 and 50 kHz, 1 h, 116–119 dB sound pressure level root mean square; sound exposure level 152 dB). At recovery time points of 2 and 5 min post-exposure, thresholds varied from −4 to +4 dB from pre-exposure threshold estimates. Thresholds after sham (control) exposures varied from −6 to +2 dB from pre-exposure estimates. The small differences in thresholds after noise and sham exposures support the hypothesis that big brown bats do not experience significant temporary threshold shifts under these experimental conditions. These results confirm earlier findings showing stability of thresholds to broadband FM sweeps at longer recovery times after exposure to broadband noise. Big brown bats may have evolved a lessened susceptibility to noise-in...

  • mouth gape angle has little effect on the transmitted signals of big brown bats Eptesicus fuscus
    Journal of the Acoustical Society of America, 2014
    Co-Authors: Laura N. Kloepper, James A. Simmons, Jason E. Gaudette, John R. Buck
    Abstract:

    Bats perform high-resolution echolocation by comparing temporal and spectral features of their transmitted pulses to the received echoes. In complex environments with moving prey, dynamically adapting the transmitted pulses can increase the probability of successful target representation and interception. This study further investigates the adaptive vocal-motor strategies of big brown bats (Eptesicus fuscus). During stationary target detection experiments, echolocation sounds were simultaneously recorded with high-speed, infrared video to examine the relationship of mouth position and movement to pulse characteristics among bats. All three bats produced strobe groups, but the proportion and frequency characteristics of the strobe group pulses differed for individual bats. Additionally, mouth gape angle had little effect on the emitted pulse characteristics, which suggests that laryngeal mechanisms drive changes in emitted pulses.

  • Temporal dynamics of echolocation during clutter navigation in Eptesicus fuscus
    Journal of the Acoustical Society of America, 2014
    Co-Authors: Alyssa Wheeler, Laura N. Kloepper, Ikuo Matsuo, James A. Simmons
    Abstract:

    The echolocating big brown bat, Eptesicus fuscus, must both avoid background objects that it may collide with such as vegetation or clutter, and identify insect prey targets. When bats fly through clutter, they emit groups of echolocation sounds in rapid succession called strobe groups. Here, we investigate the limitations of strobe grouping for flight guidance during clutter navigation. We hypothesized that as clutter conditions become extreme, bats will be no longer able to use strobe groups to navigate. We exposed bats to our laboratory flight room cluttered with plastic chains—obstacles that are acoustically similar to vegetation. Bats flew down a corridor 1.0 m wide, 0.7 m wide, or 0.4 m wide, and echolocation sounds were recorded with a 22-microphone array. We used a means clustering analysis to quantify inter-pulse intervals (IPIs) as belonging within a strobe group or between strobe groups. We found that bats made significantly more sounds per flight as the corridor width decreased. Strobe groups ...

  • Influence of mouth opening and gape angle on the transmitted signals of big brown bats (Eptesicus fuscus)
    Journal of the Acoustical Society of America, 2014
    Co-Authors: Laura N. Kloepper, James A. Simmons, Jason E. Gaudette, John R. Buck
    Abstract:

    The big brown bat (Eptesicus fuscus) produces echolocation sounds in its larynx and emits them through its mouth. The bat is presumed to change the directionality of the emitted echolocation beams by modifying its mouth opening width. We analyzed infrared video sampled at 240 fps synchronized to ultrasonic recordings from a Knowles Electret microphone sampled at 192 kHz. Mouth angles for each emitted echolocation pulse were calculated offline and compared to the pulse's time-frequency characteristics. Our results indicate that the mouth influences both the amplitude and spectral characteristics of the emitted pulse.

  • Echolocation behavior of pairs of flying Eptesicus fuscus recorded with a Telemike microphone.
    Journal of the Acoustical Society of America, 2010
    Co-Authors: Mary E. Bates, Yu Watanabe, Yuto Furusawa, Emyo Fujioka, Shizuko Hiryu, Hiroshi Riquimaroux, Jeffrey M. Knowles, James A. Simmons
    Abstract:

    Four big brown bats (Eptesicus fuscus) were flown singly and in pairs in a room containing a sparse array of vertically hanging plastic chains as obstacles. Each bat carried a lightweight radio telemetry microphone (Telemike) that recorded their emitted echolocation sounds without artifacts from Doppler shifts, directional effects, and atmospheric attenuation. The broadcasts of both bats were also recorded with two stationary ultrasonic microphones located at the far end of the flight room. The echolocation broadcasts of bats flying singly were compared to those emitted when the bats were flown together. The principal change was shifting of harmonic frequencies very slightly (