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Rabies virus and antibody in bats in Grenada and Trinidad.

Rabies virus was detected by fluorescent-antibody and mouse inoculation tests in the brain of one bat, Artibeus jamaicensis, collected at La Tante, Grenada on 19 June 1974. No rabies virus was found in the brains and/or salivary glands of 411 other Grenadian bats of 6 species tested, including 56 A. jamaicensis. Rabies neutralizing antibody was detected by the rapid fluorescent focus inhibition test (RFFIT) in 27 of 353 Grenadian bats. Positives occurred in each of the 6 species sampled, with 40.5% prevalence in A. jamaicensis. In 11 of 86 Trinidadian bats of 4 species known to carry rabies, positive sera occurred only in A. jamaicensis (18.6%) and A. lituratus (18.1%). The potential use of the REFIT indetermining rabies activity is discussed.

Animals↗

Evidence for prenatal transfer of rabies virus in the Mexican free-tailed bat (Tadarida brasiliensis Mexicana).

Fetuses were collected from four Mexican free-tailed bats (Tadarida brasiliensis mexicana) and a fetal bat cell (FBC) line was established and tested for its ability to support the replication of the ERA vaccine strain of rabies virus. Cytopathic effects were detected in ERA virus-inoculated as well as uninoculated FBC's. Immunofluorescent antibody testing of uninoculated FBC's provided no evidence for the presence of rabies virus. However, mice inoculated intracranially with supernatant fluid from uninoculated FBC's died. Enzyme-linked immunosorbent assay and immunofluorescent antibody testing revealed rabies virus in the brains of these mice. Tests with a panel of monoclonal antibodies indicated that the isolate was the same as that isolated from Mexican free-tailed bats from the southwestern United States. We conclude that the fetuses from which the FBC line was derived had been infected in utero with rabies virus. We believe this may represent the first observation of prenatal transfer of rabies virus in naturally infected bats.

Animals↗

Prevalence of rabies specific antibodies in the Mexican free-tailed bat (Tadarida brasiliensis mexicana) at Lava Cave, New Mexico.

Adult female and juvenile Mexican free-tailed bats (Tadarida brasiliensis mexicana) were collected bimonthly at Lava Cave, New Mexico from May through September. The purpose of this study was to examine the prevalence of active rabies infection as well as to determine individual immune status in these hosts. All bats were bled and examined for rabies antibody (total antibody versus IgM) utilizing a modified serum neutralization test. The brains were removed and examined by the fluorescent rabies antibody (FRA) test. No significant difference was observed in the number of adults with rabies neutralizing antibody (total) over the study period. Significant differences in rabies neutralizing antibody (total) were observed among the juveniles sampled during July and August. The number of adults with IgM specific antibody was low (15 of 750, 2%) and did not fluctuate significantly. However, the number of juveniles with IgM antibody did show increased levels in August and September. The number of adults positive by the FRA was low (4 of 750, less than 1%) and did not appear to fluctuate significantly over the study period. The number of juveniles positive by the FRA was three and one-half times higher than observed for the adults (14 of 600, 2%). These results indicate that the Mexican free-tailed bat appears to be exposed to rabies virus shortly after birth as evident by its immune status. The low prevalence (4 of 750, less than 1%) of active infection as determined by the FRA and mouse inoculation and the high prevalence (514 of 750, 69%) of IgG antibody in the adult females indicate that the Mexican free-tailed bat recovers from rabies virus infection.

Animals↗

Fine structure of the conduction system and working myocardium in the little brown bat, Myotis lucifugus.

In the little brown bat, Myotis lucifugus, topography and ultrastructure of the sinus node and the atrioventricular (AV) node resemble those in large mammalian hearts, except that the P cells in the sinus node are smaller than those in the bat AV node or those in the sinus node of slower hearts (e.g., dog, man). Despite rich innervation in the bat nodes, true neuromuscular synapses are rarely formed. Bat working cardiocytes have a well developed sarcoplasmic reticulum, but otherwise resemble working myocytes of larger mammals.

Animals↗

Effect of 67Cu-2IT-BAT-Lym-1 therapy on BCL-2 gene and protein expression in a lymphoma mouse model.

Radioimmunotherapy using monoclonal antibodies against tumor-associated antigens has been particularly promising in the treatment of radiosensitive malignancies such as lymphoma. 67Cu has excellent physical and biochemical properties for radioimmunotherapy. 67Cu-2IT-BAT-Lym-1 has been used in preclinical and clinical trials, where an exceptionally long residence time of 67Cu on tumor was observed. BCL-2, a proto-oncogene that promotes cell survival by blocking apoptotic cell death, is overexpressed in most B-cell lymphomas including Raji human Burkitt's lymphoma cells. In this study, therapeutic efficacy and BCL-2 gene and protein expression levels were examined in Raji xenografts in mice after 67Cu-2IT-BAT-Lym-1 radioimmunotherapy. 67Cu-2IT-BAT-Lym-1 therapy induced a response rate (complete and partial responses) of approximately 50%. BCL-2 gene expression was decreased 3 h after radioimmunotherapy, followed by a decrease in Bcl-2 protein by 24 h. Decreases in BCL-2 gene and protein expression preceding observations of 67Cu-2IT-BAT-Lym-1 therapeutic effect suggest that down-regulation of BCL-2 leaves cells more likely to be killed by low dose-rate radiation from radioimmunotherapy.

Animals↗

Spectral integration in the inferior colliculus of the mustached bat.

Acoustic behaviors including orientation and social communication depend on neural integration of information across the sound spectrum. In many species, spectral integration is performed by combination-sensitive neurons, responding best when distinct spectral elements in sounds are combined. These are generally considered a feature of information processing in the auditory forebrain. In the mustached bat's inferior colliculus (IC), they are common in frequency representations associated with sonar signals but have not been reported elsewhere in this bat's IC or the IC of other species. We examined the presence of combination-sensitive neurons in frequency representations of the mustached bat's IC not associated with biosonar. Seventy-five single-unit responses were recorded with the best frequencies in 10-23 or 32-47 kHz bands. Twenty-six displayed single excitatory tuning curves in one band with no additional responsiveness to a second signal in another band. The remaining 49 responded to sounds in both 10-23 and 32-47 kHz bands, but response types varied. Sounds in the higher band were usually excitatory, whereas sounds in the lower band either facilitated or inhibited responses to the higher frequency signal. Interactions were usually strongest when the higher and lower frequency stimuli were presented simultaneously, but the strength of interactions varied. Over one-third of the neurons formed a distinct subset; they responded most sensitively to bandpass noise, and all were combination sensitive. We suggest that these combination-sensitive interactions are activated by elements of mustached bat social vocalizations. If so, neuronal integration characterizing analysis of social vocalizations in many species occurs in the IC.

Acoustic Stimulation↗

Evaluation of BAT-26 as an indicator of microsatellite instability in gallbladder carcinomas.

BACKGROUND/AIMS: The genetic pathways of gallbladder cancer are not yet well defined, since the contribution of genetic abnormalities, clarified in other organs, remains questionable. Our aim was to evaluate the role of microsatellite instability in this organs carcinogenesis. METHODOLOGY: We investigated a group of 20 gallbladder carcinomas from Greek patients with regard to alterations in length of the BAT-26 mononucleotide marker--as an indicator of microsatellite instability. The findings were correlated with the presence of p53 and ras mutations, alterations of the bax and TGF-beta RII genes and tumors' clinicopathological features. Polymerase chain reaction and electrophoretic analysis in a non-denaturating 25% polyacrylamide gel was performed for the detection of BAT-26 size variations. RESULTS: None of our specimens showed microsatellite instability at the BAT-26 marker. CONCLUSIONS: BAT-26, an indicator of high-level microsatellite instability, may not be sufficient, when used alone, for determining the microsatellite instability status of gallbladder carcinomas, since these may be characterized by low-level instability. Bax and TGF-beta RII genes may not also be targets of instability in this type of tumors.

Adenocarcinoma↗

Interaction of vestibular, echolocation, and visual modalities guiding flight by the big brown bat, Eptesicus fuscus.

The big brown bat (Eptesicus fuscus) is an aerial-feeding insectivorous species that relies on echolocation to avoid obstacles and to detect flying insects. Spatial perception in the dark using echolocation challenges the vestibular system to function without substantial visual input for orientation. IR thermal video recordings show the complexity of bat flights in the field and suggest a highly dynamic role for the vestibular system in orientation and flight control. To examine this role, we carried out laboratory studies of flight behavior under illuminated and dark conditions in both static and rotating obstacle tests while administering heavy water (D2O) to impair vestibular inputs. Eptesicus carried out complex maneuvers through both fixed arrays of wires and a rotating obstacle array using both vision and echolocation, or when guided by echolocation alone. When treated with D2O in combination with lack of visual cues, bats showed considerable decrements in performance. These data indicate that big brown bats use both vision and echolocation to provide spatial registration for head position information generated by the vestibular system.

Animals↗

Bats, clocks, and rocks: diversification patterns in Chiroptera.

Identifying nonrandom clade diversification is a critical first step toward understanding the evolutionary processes underlying any radiation and how best to preserve future phylogenetic diversity. However, differences in diversification rates have not been quantitatively assessed for the majority of groups because of the lack of necessary analytical tools (e.g., complete species-level phylogenies, estimates of divergence times, and robust statistics which incorporate phylogenetic uncertainty and test appropriate null models of clade growth). Here, for the first time, we investigate diversification rate heterogeneity in one of the largest groups studied thus far, the bats (Mammalia: Chiroptera). We use a recent, robust statistical approach (whole-tree likelihood-based relative rate tests) on complete dated species-level supertree phylogenies. As has been demonstrated previously for most other groups, among-lineage diversification rate within bats has not been constant. However, we show that bat diversification is more heterogeneous than in other mammalian clades thus far studied. The whole-tree likelihood-based relative rates tests suggest that clades within the families Phyllostomidae and Molossidae underwent a number of significant changes in relative diversification rate. There is also some evidence for rate shifts within Pteropodidae, Emballonuridae, Rhinolophidae, Hipposideridae, and Vespertilionidae, but the significance of these shifts depends on polytomy resolution within each family. Diversification rate in bats has also not been constant, with the largest diversification rate shifts occurring 30-50 million years ago, a time overlapping with the greatest number of shifts in flowering plant diversification rates.

Animals↗

EBLV1 circulation in natural bat colonies of Eptesicus serotinus: a six year survey.

The serotine bat (Eptesicus serotinus) accounts for 95 % of cases of human exposition to EBLV1. The aim of this study was to focus on the epidemiology and pathogenesis of EBLV1 infection in the serotine bat. Our first objective was the development of an RT-PCR technique for the specific detection of EBLV1 RNA in oro-pharyngeal swabs. This technique showed better performance than the classical immunofluorescence (IF) on brain in detecting EBLV1 in healthy flying bats. We have used this technique together with antibody detection by the fluorescent focus inhibition test (FFIT) to investigate EBLV1 circulation in 19 natural colonies of serotine bats in Andalusia (Spain) from 1998 to 2003. The survey was based on 1223 different captures of 1080 individuals that were ring banded, sampled and released. Individuals that were repeatedly captured were always found in the same colony even though some colonies were less than five Km apart. Viral circulation was detected in nine colonies either by RT-PCR, serology or both. Each colony showed a different temporal pattern of viral circulation suggesting independent endemic circulation. Some positive individuals were captured healthy in following campaigns evidencing survival after viral infection.

Animals↗

Duration selectivity of bat inferior collicular neurons improves with increasing pulse repetition rate.

Insectivorous big brown bats, Eptesicus fuscus, progressively increase the pulse repetition rate (PRR) throughout the course of hunting. While increasing PRR conceivably facilitates bats to extract information about the targets, it also inevitably affects sensitivity of their auditory neurons to pulse parameters. The present study examined the effect of increasing PRR on duration selectivity of this bat's inferior collicular (IC) neurons by comparing their impulse-duration functions determined at different PRRs. Impulse-duration functions plotted with the number of impulses in response to single pulses against pulse duration at different PRRs were described as short-pass, band-pass, long-pass, and all-pass. Short- or long-pass neurons discharged maximally to a range of short or long pulse durations. Band-pass neurons discharged maximally to one pulse duration. These three types of IC neurons were called duration tuned neurons. All-pass neurons were not duration tuned because they did not discharge maximally to any pulse duration. Increasing PRR improved duration selectivity of IC neurons by (1) increasing the number of duration tuned neurons; (2) decreasing the critical duration concomitant with increasing slope of the impulse-duration function; and (3) decreasing the 50% duration range of the impulse-duration function. This improved duration selectivity with PRR may potentially facilitate prey capture by bats.

Acoustic Stimulation↗

[Outbreaks of human rabies transmitted by vampire bats in Alto Baudó and Bajo Baudó municipalities, department of chocó, Colombia, 2004-2005].

INTRODUCTION: During months May to July 2004, a rabies outbreak in the Embera community of Birrinchao, in the Purricha river basin department of Choc6 was reported with 14 human deaths. Another rabies outbreak was reported in January 2005 in the black communities of Pató and Nauca in the neighboring municipality of Alto Baudó with 3 human deaths. OBJECTIVES: To describe the largest outbreaks of human rabies transmitted by vampire bats reported in Colombia to date. To describe the diagnostic laboratory techniques used, and the activities undertaken for the control of rabies in the area. To discuss the epidemiologic significance and public health implications of these rabies outbreaks. MATERIALS AND METHODS: Rabies diagnosis was achieved by direct immunofluorescence, inoculation of mice and immunohistochemistry. Typing of the virus was achieved by indirect immunofluorescence using monoclonal antibodies. Rabies control activities were undertaken in Bajo Baudó consisting in a population census, human vaccination and application of antirabies sera, vaccination of dogs and cats, and application of anticoagulant to bats. RESULTS: Four human cases were confirmed as positive for rabies in both rabies outbreaks. Another 13 rabies cases in humans were inferred by strong epidemiological links. Rabies antigenic variant 3 was identified in the samples studied. Rabies control activities were conducted for a human rabies outbreak caused by vampire bats. CONCLUSIONS: The human rabies outbreak in Bajo Baudó has been the largest reported in Colombia. It was caused by vampire bats, showing that these animals are a threat for human health. The implementation of control strategies for this kind of epizootic outbreaks is needed in South America. It remains unknown whether there is a link between this outbreak and one reported 6 months later in the neighboring municipality of Alto Baudó.

Adolescent↗

An immunohistochemical study of gut endocrine cells in two species of insectivorous vespertilinid bats (Chiroptera: Pipistrellus abramus and Plecotus auritus sacrimontis).

11 endocrine cell types immunoreactive for either 5-hydroxytryptamine (5-HT), somatostatin, gastrin, cholecystokinin (CCK), gastric inhibitory peptide (GIP), motilin, secretin, neurotensin, pancreatic glucagon, enteroglucagon or bovine pancreatic polypeptide (BPP) were found in gastrointestinal tract of 2 species of insectivorous bats. 5 of these 11 types of endocrine cells were located in the stomach and all 11 types of endocrine cells were found in the intestine. However, the distribution and relative frequency of each immunoreactive endocrine cell varied among the cell types and between the 2 species of bats examined. In Brunner's glands, gastrin- and 5-HT-immunoreactive cells were detected very rarely in Pipistrellus and only occasionally in Plecotus. The present results obtained from the insectivorous bats were compared with those of the sanguivorous vampire bats.

Animals↗

Occurrence of the bat tick Ornithodoros (Alectorobius) Kelleyi Cooley & Kohls (Acari: Argasidae) in Costa Rica and its relation to human bites.

Several persons from two localities in Costa Rica (San Rafael de Coronado, 1510 m and Dulce Nombre de Tres Ríos, 1445 m) were bitten by ticks, subsequently identified as Ornitohodoros (A.) Kelleyi (Argasidae), commonly associated with bats. In the attics of their homes, live adults, larvae, nymphs and skins were found in the bat guano. Since there are no records of adult argasids in this country, a laboratory colony was established to observe the biology of these ticks and their association with bats. In this particular case, the bats were Molossidae and Vespertilionidae, both insectivorous. Adults and last nymphal ticks easily fed on suckling white mice in the dark; feeding lasts from 20 to 40 minutes, when abundant coxal fluid is produced; oviposition occurs from 14 to 27 days later. Comparison of the most common structures of both whole larvae and larval skins revealed no significant differences, taxonomically important, since according to the habits of the Argasidae, it is easier to find larval molts than live specimens.

Adult↗

Study of the presence of rabies virus in indigenous bats.

One hundred and thirteen fruit eating and insectivorous bats were captured from different parts of Bangladesh. Antemortem and post mortem examinations of the bats for rabies were conducted. Microscopic studies and biological tests were carried-out with bat's brain for the detection of rabies virus. The results were negative. It may therefore, be concluded that the insectivorous and fruit eating bats from different parts of Bangladesh do not act as the reservoir for rabies virus.

Animals↗

Rabies virus infection of a flying fox bat, Pteropus policephalus in Chandigarh, Northern India.

The present communication reports for the first time in South East Asia an active infection of frugivorous flying fox bat (Pteropus poliocephalus) with a virus belonging to the Rhabdo virus group -- a bat virus. Negri body like structures were demonstrated by Seller's stain and direct immunofluorescence in the brain and salivary gland of the dead bat. The virus was isolated after intracerebral inoculation of homogenate of the bat brain, salivary gland or brown fat separately in new born mice.

Animals↗

Pathogenesis and immune response to Paracoccidioides brasiliensis in the fructivorous bat, Artibeus lituratus.

Groups of neotropical bats (Artibeus lituratus) were inoculated by the intraperitoneal or intranasal routes with varying doses of yeast phase Paracoccidioides brasiliensis. Bats infected with 10(6) viable yeast cells intraperitoneally developed fatal, disseminated disease, with delayed hypersensitivity appearing within 2 weeks. No precipitating antibodies were detected up to 7 weeks post-exposure. After intranasal instillation of 10(5) viable P. brasiliensis, the disease spread from the lung to the spleen by 3 weeks and to the liver by 9 weeks. As few as 10 viable cells were capable of causing pulmonary disease. Antibodies were detected at 5 weeks and persisted for several weeks thereafter. No viable P. brasiliensis was recovered from the intestines or fecal contents of any bats. Artibeus lituratus appears to be very susceptible to paracoccidioidomycosis by the respiratory route. The resulting immune response is characterized by delay appearance of precipitating antibodies and a moderate degree of delayed hypersensitivity. The pathogenesis of the resulting disease is similar to that observed in humans. The absence of intestinal involvement, even in chronic systemic disease, suggests that bats do not play a direct role in dissemination of this fungus in nature.

Animals↗

[Enterobacteria of bats (Chiroptera) (author's transl)].

The aerobic gram-negative faecal flora of 38 bats consisting of 10 species and genera respectively, of Microchiroptera, and of 4 species and genera respectively, of Megachiroptera was studied (Table 1 and 3). There were no specific differences between Insectivora and Frugivora: E. coli 15-24%, Citrobacter 8-10%, Enterobacter-Klebsiella-group 40-43% and Proteus-group 28-30% (Table 2). The overwhelming majority of the isolated bacteria were lactose-positive (Table 3), corresponding to the membership of the bats to the mammals. The vampire bats (Desmodus rotundus), however, nourishing exclusively with mammalian blood, possess a fundamental other faecal flora. Here we always found Aeromonas hydrophila sometimes as a pure culture and sometimes in combination with E. coli, Enterobacter, Providencia, and Arizona. The normal habitat of Aeromonas hydrophila in vampire bats suggests that these bacteria are necessary for digest the drunken blood in a similar manner as in leechs. The observations were discussed regarding their ecological, epidemiological, and phylogenetic significances.

Animals↗