Bat Exposure Research Articles

High levels of activity of bats at gold mining water bodies: implications for compliance with the International Cyanide Management Code

Wildlife and livestock are known to visit and interact with tailings dam and other wastewater impoundments at gold mines. When cyanide concentrations within these water bodies exceed a critical toxicity threshold, significant cyanide-related mortality events can occur in wildlife. Highly mobile taxa such as birds are particularly susceptible to cyanide toxicosis. Nocturnally active bats have similar access to uncovered wastewater impoundments as birds; however, cyanide toxicosis risks to bats remain ambiguous. This study investigated activity of bats in the airspace above two water bodies at an Australian gold mine, to assess the extent to which bats use these water bodies and hence are at potential risk of exposure to cyanide. Bat activity was present on most nights sampled during the 16-month survey period, although it was highly variable across nights and months. Therefore, despite the artificial nature of wastewater impoundments at gold mines, these structures present attractive habitats to bats. As tailings slurry and supernatant pooling within the tailings dam were consistently well below the industry protective concentration limit of 50mg/L weak acid dissociable (WAD) cyanide, wastewater solutions stored within the tailings dam posed a minimal risk of cyanide toxicosis for wildlife, including bats. This study showed that passively recorded bat echolocation call data provides evidence of the presence and relative activity of bats above water bodies at mine sites. Furthermore, echolocation buzz calls recorded in the airspace directly above water provide indirect evidence of foraging and/or drinking. Both echolocation monitoring and systematic sampling of cyanide concentration in open wastewater impoundments can be incorporated into a gold mine risk-assessment model in order to evaluate the risk of bat exposure to cyanide. In relation to risk minimisation management practices, the most effective mechanism for preventing cyanide toxicosis to wildlife, including bats, is capping the concentration of cyanide in tailings discharged to open impoundments at 50mg/L WAD.

Understanding human - bat interactions in NSW, Australia: improving risk communication for prevention of Australian bat lyssavirus.

BackgroundAustralian bat lyssavirus (ABLV) infects a number of flying fox and insectivorous bats species in Australia. Human infection with ABLV is inevitably fatal unless prior vaccination and/or post-exposure treatment (PET) is given. Despite ongoing public health messaging about the risks associated with bat contact, surveillance data have revealed a four-fold increase in the number of people receiving PET for bat exposure in NSW between 2007 and 2011. Our study aimed to better understand these human – bat interactions in order to identify additional risk communication messages that could lower the risk of potential ABLV exposure. All people aged 18 years or over whom received PET for non-occupation related potential ABLV exposure in the Hunter New England Local Health District of Australia between July 2011 and July 2013 were considered eligible for the study. Eligible participants were invited to a telephone interview to explore the circumstances of their bat contact. Interviews were then transcribed and thematically analysed by two independent investigators.ResultsOf 21 eligible participants that were able to be contacted, 16 consented and participated in a telephone interview. Participants reported bats as being widespread in their environment but reported a general lack of awareness about ABLV, particularly the risk of disease from bat scratches. Participants who attempted to ‘rescue’ bats did so because of a deep concern for the bat’s welfare. Participants reported a change in risk perception after the exposure event and provided suggestions for public health messages that could be used to raise awareness about ABLV.ConclusionsReframing the current risk messages to account for the genuine concern of people for bat welfare may enhance the communication. The potential risk to the person and possible harm to the bat from an attempted ‘rescue’ should be promoted, along with contact details for animal rescue groups. The potential risk of ABLV from bat scratches merits greater emphasis.

Current and future approaches to the therapy of human rabies

Human rabies has traditionally been considered a uniformly fatal disease. However, recent decades have seen several instances in which individuals have developed clinical signs of rabies, but survived, usually with permanent neurologic sequelae. Most of these patients had received prophylactic rabies vaccine before the onset of illness. The best outcomes have been seen in patients infected with bat viruses, which appear to be less virulent for humans than strains associated with other rabies vectors. In 2003, an article by rabies experts suggested that survival might be improved through a combination of vaccine, anti-rabies immunoglobulin, antiviral drugs and the anesthetic ketamine, which had shown benefit in an animal model. One year later, a girl in Milwaukee who developed rabies after bat exposure was treated with some of these measures, plus a drug-induced (therapeutic) coma, and survived her illness with mild neurologic sequelae. Although the positive outcome in this case has been attributed to the treatment regimen, it more likely reflects the patient’s own brisk immune response, as anti-rabies virus antibodies were detected at the time of hospital admission, even though she had not been vaccinated. This conclusion is supported by the failure of the “Milwaukee Protocol” to prevent death in numerous subsequent cases. Use of this protocol should therefore be discontinued. Future research should focus on the use of animal models to improve understanding of the pathogenesis of rabies and for the development of new therapeutic approaches.

Evidence of rabies virus exposure among humans in the Peruvian Amazon.

In May of 2010, two communities (Truenococha and Santa Marta) reported to be at risk of vampire bat depredation were surveyed in the Province Datem del Marañón in the Loreto Department of Perú. Risk factors for bat exposure included age less than or equal to 25 years and owning animals that had been bitten by bats. Rabies virus neutralizing antibodies (rVNAs) were detected in 11% (7 of 63) of human sera tested. Rabies virus ribonucleoprotein (RNP) immunoglobulin G (IgG) antibodies were detected in the sera of three individuals, two of whom were also seropositive for rVNA. Rabies virus RNP IgM antibodies were detected in one respondent with no evidence of rVNA or RNP IgG antibodies. Because one respondent with positive rVNA results reported prior vaccination and 86% (six of seven) of rVNA-positive respondents reported being bitten by bats, these data suggest nonfatal exposure of persons to rabies virus, which is likely associated with vampire bat depredation.

Effect of Media Warnings on Rabies Postexposure Prophylaxis, France

Effect of Media Warnings on Rabies Postexposure Prophylaxis, France

Headspace stir bar sorptive extraction–gas chromatography/mass spectrometry characterization of the diluted vapor phase of cigarette smoke delivered to an in vitro cell exposure chamber

Advanced smoke generation systems, such as the Borgwaldt RM20S ® smoking machine used in combination with the BAT exposure chamber, allow for the generation, dilution and delivery of fresh cigarette smoke to cell or tissue cultures for in vitro cell culture analyses. Recently, our group confirmed that the Borgwaldt RM20S ® is a reliable tool to generate and deliver repeatable and reproducible exposure concentrations of whole smoke to in vitro cultures [1]. However, the relationship between dose and diluted smoke components found within the exposure chamber has not been characterized. The current study focused on the development of a headspace stir bar sorptive extraction (HSSE) method to chemically characterize some of the vapor phase components of cigarette smoke generated by the Borgwaldt RM20S ® and collected within a cell culture exposure chamber. The method was based on passive sampling within the chamber by HSSE using a Twister™ stir bar. Following exposure, sorbed analytes were recovered using a thermal desorption unit and a cooled injection system coupled to gas chromatograph/mass spectrometry for identification and quantification. Using the HSSE method, sixteen compounds were identified. The desorption parameters were assessed using ten reference compounds and the following conditions led to the maximal response: desorption temperature of 200 °C for 2 min with cryofocussing temperature of −75 °C. During transfer of the stir bars to the thermal desorption system, significant losses of analytes were observed as a function of time; therefore, the exposure-to-desorption time interval was kept at the minimum of 10 ± 0.5 min. Repeatability of the HSSE method was assessed by monitoring five reference compounds present in the vapor phase (10.1–12.9% RSD) and n-butyl acetate, the internal standard (18.5% RSD). The smoke dilution precision was found to be 17.2, 6.2 and 11.7% RSD for exposure concentrations of 1, 2 and 5% (v/v) cigarette vapor phase in air, respectively. A linear response of analyte abundance was observed as a function of dilution. Extrapolation to 100% (v/v) cigarette vapor phase, i.e., undiluted smoke, gave yields for the five compounds ranging from 6 to 450 ng for 10 min exposure.

Rabies Diagnosis and Unusual Manifestations

This study is a retrospective clinical and neuropathological record review of 47 patients with rabies seen over a 30-year period at one specialist center for neurological and psychiatric disorders in Bangalore, India. In 42 patients, the diagnosis was confirmed by postmortem pathology (Negri bodies, immunohistochemical identification of rabies antigen, or both). Of the 47 patients, 33 had a history of a dog bite and 1 had a history of a fox bite. None had known bat exposure. Only half of the patients received postexposure vaccination, and half of these were with Semple sheep brain …

Bat-Associated Leptospirosis

Leptospirosis is a globally prevalent disease that affects humans, causing systemic illness that may lead to multi-organ involvement. Clinical signs include sudden fever, general malaise, muscular pain, conjunctival suffusion, and jaundice. Disease is caused by pathogenic bacteria including over 200 serologic variants. Most serologic variants have primary reservoirs in wild mammals, which continually infect and colonize domesticated animals. The organism has been recovered from rats, swine, dogs, cattle, and other animals, notably bats. Most studies have focused on domestic animals as reservoir hosts; however, because of their abundance, spatial distribution, and interrelationship with domestic animals, bats are becoming an epidemiologically significant source of leptospires. We present a case of serologically confirmed leptospirosis after bat exposure to add to the growing literature of bats as a possible source of transmission. Recognition of the common presentation of leptospirosis and Weil's disease, and identification of animal vectors, including bats, allows for the selection of appropriate antibiotic management to aid in resolution of symptomotology.

Bat-associated Rabies: Reassessing the Risk of Bedroom Exposure

Source: De Serres G, Skowronski DM, Mimault P, et al. Bats in the bedroom, bats in the belfry: reanalysis of the rationale for rabies postexposure prophylaxis. Clin Infect Dis. 2009;48:1493–1499; doi: 10.1086/598998Canadian researchers sought to determine the necessity of postexposure rabies prophylaxis (RPEP) for individuals exposed to a bat but without knowledge of direct contact — eg, bat seen in the room of a sleeping child, no evidence of a bite, and bat not available for testing. To estimate the proportion of the population with bat exposure annually, a random-digit-dial telephone survey of residents in Quebec was conducted from January through March 2007.Participants were asked whether they or their child had been in the presence of a bat; if so, additional questions sought details related to bat exposure and intervention. Exposure was classified as direct contact if there was recognized physical contact with a bat. Household exposure in the absence of recognized physical contact was divided into three categories including bedroom exposure, bedroom access (bat found elsewhere in the house with a door open to allow bat access to the individual while sleeping), and other exposure circumstances.From a telephone survey of 14,453 households (63% of those eligible) involving 36,445 individuals, only four individuals reported direct contact with a bat without a known bite in the previous 12 months. Another 152 reported indoor proximity to a bat without known contact. These exposures included bedroom exposures in 34, bedroom access in 41, and other types in 77. None of the four with direct contact and none of the 34 with bedroom exposure sought medical advice but two (5%) of the 41 who reported bedroom access to bats sought medical advice and both received RPEP.The total exposed without direct contact (152) was used as a proportion of the population of Quebec (7.6 million) to estimate the expected number of exposures in the province (56,605). From 1990 through 2007 in Canada and the US, there were 36 individuals with bat-acquired rabies. Of these, 17 had no recognized physical contact; two reported bedroom exposure. Based on these figures, the system would need to treat 2.7 million people to prevent one case of rabies and the investigation and treatment would involve a huge outlay of personnel and a cost of $2 billion (in Canadian $) for biological products and virologic analyses alone. The authors’ most sensitive calculation assumed that all 17 of the rabies cases with no recognized physical contact had a bedroom bat exposure. Given this assumption, the system would need to treat 314,000 individuals to prevent one case of rabies acquired through bedroom exposure.The authors conclude that bedroom exposure to bats is fairly frequent in Quebec and contracting rabies from such an exposure is quite rare. Even recognizing the almost universal fatality from rabies, the low cost-benefit ratio suggests that current recommendations to consider RPEP after non-bite bedroom exposure should be reconsidered.Dr Shane has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.De Serres and colleagues present compelling evidence to reconsider the liberal approach toward RPEP when evidence of bites is lacking. Despite the inherent limitations of a population-based survey and potential regional differences between Quebec and other areas where frequency of bat exposures may vary, the number needed to treat (NNT) analysis outlines the tremendous resources involved in RPEP. In an era of limited resources and reduced vaccine supply, a reconsideration of our liberal use of RPEP for bat exposures is warranted. (See also AAP Grand Rounds, July 2008;20:5.1)The June 2009 revision of the ACIP guidelines to reduce the number of doses of RPEP from five to four emanated from efforts to address a rabies vaccination shortage in 2007. Population-based evidence that levels of antibody following four and five doses of rabies vaccine were equivalent and absence of infection in those who received four versus five doses of RPEP provided the basis for these recommended modifications to the schedule.2,3 Although this reduction in doses for RPEP has the potential to reduce the expenditures calculated by the authors in their economic analysis, implementation of the reduced vaccination schedule is unlikely to have a significant impact on the total expenditures associated with RPEP. Human resources comprise the greatest expenditures required to evaluate each suspected exposure.4

Bats in the Bedroom, Bats in the Belfry: Reanalysis of the Rationale for Rabies Postexposure Prophylaxis

We assessed the scientific basis and practical implications of recommendations made since the late 1990s to offer rabies postexposure prophylaxis (RPEP) for occult bat encounters, including recommendations to offer RPEP to persons with bedroom exposure to a bat while sleeping without evidence of direct physical contact. The number needed to treat after bedroom exposure to a bat was calculated as the percentage of population exposed multiplied by the inverse of crude rabies incidence. Bedroom exposure was estimated in a population survey of 14,453 households. Incidence was based on reported human cases in Canada and the United States, 1990-2007. In the population surveyed, bedroom bat exposure while sleeping and without known physical contact occurred at an annual rate of 0.099%. We estimate that <5% of eligible persons with bedroom exposure receive RPEP as recommended. The incidence of human rabies due to bedroom bat exposure without recognized contact was 1 case per 2.7 billion person-years. The number needed to treat to prevent a single case of human rabies in that context ranges from 314,000 to 2.7 million persons. A total of 293-2500 health care professionals working full-time for a full year would be required to prevent a single human case of bat rabies due to bedroom exposure without recognized contact. Amounts of Can $228 million to Can $2.0 billion are additionally required for associated material costs. Human rabies acquired through bedroom exposure to a bat while sleeping and without recognized contact is rare. Conversely, such exposures are not uncommon in the population, and the resources required for associated RPEP are orders of magnitude higher than those required for most interventions that are considered to be reasonable. Current RPEP recommendations related to occult bat contact should be reconsidered.

The cost of preventing rabies at any cost: Post-exposure prophylaxis for occult bat contact

Investigations conducted by public health in Quebec, Canada, following report of human exposure to a bat were reviewed to evaluate the implementation of the recommendation for rabies post-exposure prophylaxis (RPEP) for household bat exposure (without documented direct contact). Of all RPEP recommended, 12% was for direct bat contact with bite, 7% for direct bat contact without known bite and 81% for household exposure. When bat was not available for testing, RPEP was almost always recommended. Household bat exposure has become the most frequent reason for RPEP administration. Given the rarity of rabies, RPEP recommendations related to household bat exposure may warrant review.

Human Rabies—Alberta, Canada, 2007

On April 26, 2007, a patient from Alberta, Canada, died after 9 weeks in an intensive care unit (ICU) from encephalitis caused by a rabies virus variant associated with silver-haired bats. This report summarizes the clinical course of disease in that patient, who was treated using the Milwaukee Protocol, an experimental treatment protocol similar to one used for the rabies survivor described in 2005. This report also describes the subsequent epidemiologic investigations by three regional public health departments in Alberta. Rabies continues to be a cause of human death in the developed and developing world. The findings in this report underscore the need for continued public education that promotes rabies prevention and postexposure prophylaxis while emphasizing the importance of bat exposure in rabies transmission.

Corrections

We clarify that the death from rabies in Canada reported in the Feb. 26 issue[1][1] is the same case as that reported in the Feb. 29, 2008, issue of Morbidity and Mortality Weekly Report .[2][2] 1. 1.[↵][3] McDermid RC, Saxinger L, Lee B, et al. Human rabies encephalitis following bat exposure:

Bat Rabies in the United States and Canada from 1950 through 2007: Human Cases With and Without Bat Contact

Since the 1980s, rare cases of rabies in humans in Canada and the United States have been almost exclusively caused by the bat-variant virus. We reviewed indigenously acquired cases of bat-variant rabies in humans in Canada and the United States from 1950 through 2007. Of 61 cases identified, 5 occurred after organ transplantation and were excluded from further analysis. A bite was reported by 22 (39%) of the case patients, 9 (16%) had a direct contact (i.e., were touched by a bat) but no history of a bite, 6 (11%) found bats in their home (2 [4%] in the room where they slept) but reported no direct contact, and 19 (34%) reported no history of bat exposure whatsoever. With the exception of California (8 cases) and Texas (7 cases), no state or province had >3 cases. Of the case patients, 76% were men, and 40% were 10-29 years of age. The median incubation period was 7 weeks (<10 weeks in 72% of cases). The incidence of bat-variant rabies cases increased from 2.2 per billion person-years in 1950-1989 to 6.7 per billion person-years in 1990-2007. Of 36 case patients with bat rabies described since 1990, 16 had no history of direct bat contact; 2 (13%) of the 16 would have qualified for rabies postexposure prophylaxis on the basis of exposure criteria expanded in 1995 to include bats that were in the same room as a sleeping person. The incidence of rabies for this type of exposure was 0.6 cases per billion person-years. The true preventable proportion of cases and the number needed to treat with rabies postexposure prophylaxis to prevent 1 case would be useful information to inform the current guidelines.

Human rabies encephalitis following bat exposure: failure of therapeutic coma

The case: A healthy 73-year-old man had pain in his left shoulder. He presented to a regional hospital 1 week later with fever, dysphagia, muscle spasms and progressive generalized weakness. His neurologic status deteriorated, which prompted transfer to a tertiary care hospital. Upon the patient's

Phototoxic process after rapid photosensitive membrane damage of 5,5″-bis(aminomethyl)-2,2′:5′,2″-terthiophene dihydrochloride

We report a new aspect of rapid (<30 s) light-induced cell membrane damage photosensitized by 5,5″-bis(aminomethyl)-2,2′:5′,2″-terthiophene dihydrochloride (BAT), which is a water-soluble α-terthienyl analogue, using a high-power laser (light intensity 1.6 W cm −2). In this paper, we will discuss the relationship between the exposure time of the cells to the photosensitizer and the phototoxic process. Three toxic processes can be identified: first, a non-light-mediated toxicity dependent on BAT-cell incubation; second, a phototoxicity independent of BAT exposure time when the BAT concentration is in the 2–10-μM range; third, a phototoxicity dependent on BAT exposure time when BAT concentration becomes 20 μM. The cytotoxicity decreases when α-tocopherol, an antioxidant, is added to a cell membrane. This pattern of phototoxicity is the typical of a phospholipid peroxidation chain reaction and oxidative damage of membrane proteins triggered by a reactive oxygen species generated by a triplet state of BAT. The BAT exposure time is clearly correlated with the partition of the photosensitizer in the cell membrane and inside the cell.

Human Rabies Associated with Bat Exposure but Not Bites

Pediatric Nurse Practitioner and developmental consultant in the Child Developmental Unit of the Children's Hospital in Denver. Adult Nurse Practitioner in primary care and pulmonary clinic at the Veteran Affairs, New Jersey Health Care System, Lyons, N.J.

Neural Control of the α-Subunit of GsMessenger Ribonucleic Acid in Rat Brown Adipose Tissue*

Neural stimulation of rat interscapular brown adipose tissue (IBAT) can greatly modify transmembrane signalling in this tissue. As part of an investigation into the molecular mechanisms of such modulation we have examined the effects of surgical denervation of BAT and cold exposure (a treatment that increases neural stimulation of BAT) on the levels of mRNA encoding for the alpha-subunit of Gs, the GTP-binding protein that regulates adenylate cyclase. The G alpha s mRNA content of BAT per unit RNA was 5-10 times greater than that of lung, liver, or caudate-putamen. Surgical denervation of BAT of warm-adapted rats reduced G alpha s mRNA content by 30% within 8 h postsurgery and by 65% by 72 h. Concurrent infusion of norepinephrine completely prevented the denervation-induced decline in G alpha s mRNA at 72 h. Infusion of the beta-adrenergic agonist isoproterenol also prevented the denervation-induced decline in G alpha s mRNA, but infusion of the alpha 1-adrenergic agonist phenylephrine was without effect. Exposing rats to 4 C for 3 days approximately doubled the level of G alpha s mRNA. Interestingly, surgical denervation did not prevent the cold-induced increase in G alpha s mRNA levels, indicating that this effect is independent of local innervation. Despite reducing G alpha s mRNA levels by about 60%, surgical denervation failed to alter the concentration of G alpha s protein in IBAT membranes of warm-adapted rats, as determined by immunoblotting. Previous work indicates that cold exposure does not increase the concentration of G alpha s in IBAT membranes. Taken with the present results, these data indicate that there is no simple relationship between tissue G alpha s mRNA content and membrane G alpha s concentration in IBAT.