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1.  Knowledge, attitudes and practices regarding rabies and exposure to bats in two rural communities in Guatemala 
BMC Research Notes  2015;8:955.
Rabies is a fatal encephalitis caused by rabies virus, of the genus Lyssavirus. The principal reservoir for rabies in Latin America is the common vampire bat (Desmodus rotundus), which feeds routinely on the blood of cattle, and when livestock are scarce, may prey on other mammals, including humans. Although rabies is endemic in common vampire bat populations in Guatemala, there is limited research on the extent of exposure to bats among human populations living near bat refuges.
A random sample of 270 of 473 households (57%) in two communities located within 2 Km of a known bat roost was selected and one adult from each household was interviewed. Exposure to bats (bites, scratches or bare skin contact) was reported by 96 (6%) of the 1,721 residents among the selected households. Of those exposed, 40% received rabies post-exposure prophylaxis. Four percent of household respondents reported that they would seek rabies post exposure prophylaxis if they were bitten by a bat.
These findings demonstrate that exposure to bats in communities near bat roosts is common but recognition of the potential for rabies transmission from bats is low. There is a need for educational outreach to raise awareness of bat-associated rabies, prevent exposures to bats and ensure appropriate health-seeking behaviours for bat-inflicted wounds, particularly among communities living near bat roosts in Guatemala.
PMCID: PMC4302579  PMID: 25576098
Rabies; Bat bite; Health practices; Post-exposure prophylaxis; Guatemala; Rabies prevention; Vampire bat
2.  Cross sectional survey of human-bat interaction in Australia: public health implications 
BMC Public Health  2014;14:58.
Flying foxes (megachiroptera) and insectivorous microbats (microchiroptera) are the known reservoirs for a range of recently emerged, highly pathogenic viruses. In Australia there is public health concern relating to bats’ role as reservoirs of Australian Bat Lyssavirus (ABLV), which has clinical features identical to classical rabies. Three deaths from ABLV have occurred in Australia. A survey was conducted to determine the frequency of bat exposures amongst adults in Australia’s most populous state, New South Wales; explore reasons for handling bats; examine reported practices upon encountering injured or trapped bats or experiencing bat bites or scratches; and investigate knowledge of bat handling warnings.
A representative sample of 821 New South Wales adults aged 16 years and older were interviewed during May and June 2011, using a computer assisted telephone interview (CATI) method. Frequencies, proportions and statistical differences in proportion were performed. Using an α-value of 0.05 and power of 80%, it was calculated that a sample size of 800 was required to provide statistical significance of +/− 5% for dichotomous variables.
One-hundred-and-twenty-seven (15.5%) respondents indicated that they had previously handled a bat, being 22% (48/218) rural and 13% (78/597) urban respondents (χ2 = 9.8, p = 0.0018). Twenty one percent of males (63/304) had handled bats compared with 12% (64/517) of females (χ2 = 10.2, p = 0.0014). Overall, 42.0% (n = 345) of respondents reported having seen or heard a warning about handling bats. If faced with an injured or trapped bat, 25% (206/821) indicated that they would handle the bat, with 17% (36/206) saying that they would use their bare hands. For minor scratches, 14% (117/821) indicated that they would ignore the injury while four respondents would ignore major scratches or bites.
Previous human-bat interactions were relatively common. Bat exposures most frequently occurred with sick or injured bats, which have the highest risk of ABLV. On encountering an injured or sick bat, potentially high risk practices were commonly reported, particularly among rural males. It is important to understand why people still handle bats despite public health warnings to inform future communication strategies.
PMCID: PMC3908316  PMID: 24443960
3.  Enhanced Passive Bat Rabies Surveillance in Indigenous Bat Species from Germany - A Retrospective Study 
In Germany, rabies in bats is a notifiable zoonotic disease, which is caused by European bat lyssaviruses type 1 and 2 (EBLV-1 and 2), and the recently discovered new lyssavirus species Bokeloh bat lyssavirus (BBLV). As the understanding of bat rabies in insectivorous bat species is limited, in addition to routine bat rabies diagnosis, an enhanced passive surveillance study, i.e. the retrospective investigation of dead bats that had not been tested for rabies, was initiated in 1998 to study the distribution, abundance and epidemiology of lyssavirus infections in bats from Germany. A total number of 5478 individuals representing 21 bat species within two families were included in this study. The Noctule bat (Nyctalus noctula) and the Common pipistrelle (Pipistrellus pipistrellus) represented the most specimens submitted. Of all investigated bats, 1.17% tested positive for lyssaviruses using the fluorescent antibody test (FAT). The vast majority of positive cases was identified as EBLV-1, predominately associated with the Serotine bat (Eptesicus serotinus). However, rabies cases in other species, i.e. Nathusius' pipistrelle bat (Pipistrellus nathusii), P. pipistrellus and Brown long-eared bat (Plecotus auritus) were also characterized as EBLV-1. In contrast, EBLV-2 was isolated from three Daubenton's bats (Myotis daubentonii). These three cases contribute significantly to the understanding of EBLV-2 infections in Germany as only one case had been reported prior to this study. This enhanced passive surveillance indicated that besides known reservoir species, further bat species are affected by lyssavirus infections. Given the increasing diversity of lyssaviruses and bats as reservoir host species worldwide, lyssavirus positive specimens, i.e. both bat and virus need to be confirmed by molecular techniques.
Author Summary
According to the World Health Organization rabies is considered both a neglected zoonotic and a tropical disease. The causative agents are lyssaviruses which have their primary reservoir in bats. Although bat rabies is notifiable in Germany, the number of submitted bats during routine surveillance is rarely representative of the natural bat population. Therefore, the aim of this study was to include dead bats from various sources for enhanced bat rabies surveillance. The results show that a considerable number of additional bat rabies cases can be detected, thus improving the knowledge on the frequency, geographical distribution and reservoir-association of bat lyssavirus infections in Germany. The overall proportion of positives was lower than during routine surveillance in Germany. While the majority of cases were found in the Serotine bat and characterized as European bat lyssavirus type 1 (EBLV-1), three of the four EBLV-2 infections detected in Germany were found in Myotis daubentonii during this study.
PMCID: PMC4006713  PMID: 24784117
4.  Using Serology to Assist with Complicated Post-Exposure Prophylaxis for Rabies and Australian Bat Lyssavirus 
Australia uses a protocol combining human rabies immunoglobulin (HRIG) and rabies vaccine for post-exposure prophylaxis (PEP) of rabies and Australian bat lyssavirus (ABLV), with the aim of achieving an antibody titre of ≥0.5 IU/ml, as per World Health Organization (WHO) guidelines, as soon as possible.
Methodology/Principal Findings
We present the course of PEP administration and serological testing for four men with complex requirements. Following dog bites in Thailand, two men (62 years old, 25 years old) received no HRIG and had delayed vaccine courses: 23 days between dose two and three, and 18 days between dose one and two, respectively. Both seroconverted following dose four. Another 62-year-old male, who was HIV-positive (normal CD4 count), also suffered a dog bite and had delayed care receiving IM rabies vaccine on days six and nine in Thailand. Back in Australia, he received three single and one double dose IM vaccines followed by another double dose of vaccine, delivered intradermally and subcutaneously, before seroconverting. A 23-year-old male with a history of allergies received simultaneous HRIG and vaccine following potential ABLV exposure, and developed rash, facial oedema and throat tingling, which was treated with a parenteral antihistamine and tapering dose of steroids. Serology showed he seroconverted following dose four.
These cases show that PEP can be complicated by exposures in tourist settings where reliable prophylaxis may not be available, where treatment is delayed or deviates from World Health Organization recommendations. Due to the potentially short incubation time of rabies/ABLV, timely prophylaxis after a potential exposure is needed to ensure a prompt and adequate immune response, particularly in patients who are immune-suppressed or who have not received HRIG. Serology should be used to confirm an adequate response to PEP when treatment is delayed or where a concurrent immunosuppressing medical condition or therapy exists.
Author Summary
In Australia, the administration of rabies post-exposure prophylaxis (PEP) occurs for potentially exposed returned travellers from endemic regions or for potential local exposure to Australian Bat Lyssavirus. For Australian tourists, delays in commencing PEP or not receiving HRIG or all recommended doses of vaccine are common. We report a case series where serology provided information in four patients with delayed, incomplete, or complicated PEP treatment. Three of these patients reported a dog bite in Thailand and the fourth was scratched by a bat and had bat urine enter his eye in Australia. Management was complicated by lack of HRIG administration, delays in the recommended timeframe for receipt of vaccine doses, and immunosuppression caused by co-administration of steroids and by HIV infection with a normal CD4 count. All patients seroconverted but this was delayed in some cases, and in the HIV-positive subject required a double dose of vaccine delivered intradermally and subcutaneously. In complex or non-standard PEP delivery, including delayed treatment and immunosuppression due to steroid treatment, HIV or another immunosuppressing medical condition, serology can be used to guide further treatment and should be used to confirm seroconversion.
PMCID: PMC3584984  PMID: 23469301
5.  Understanding human – bat interactions in NSW, Australia: improving risk communication for prevention of Australian bat lyssavirus 
BMC Veterinary Research  2014;10:144.
Australian 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.
Of 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.
Reframing 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.
PMCID: PMC4107573  PMID: 24984790
Lyssavirus; Bats; Australia; Risk; Communication; Prevention
6.  Rabies Virus Infection in Eptesicus fuscus Bats Born in Captivity (Naïve Bats) 
PLoS ONE  2013;8(5):e64808.
The study of rabies virus infection in bats can be challenging due to quarantine requirements, husbandry concerns, genetic differences among animals, and lack of medical history. To date, all rabies virus (RABV) studies in bats have been performed in wild caught animals. Determining the RABV exposure history of a wild caught bat based on the presence or absence of viral neutralizing antibodies (VNA) may be misleading. Previous studies have demonstrated that the presence of VNA following natural or experimental inoculation is often ephemeral. With this knowledge, it is difficult to determine if a seronegative, wild caught bat has been previously exposed to RABV. The influence of prior rabies exposure in healthy, wild caught bats is unknown. To investigate the pathogenesis of RABV infection in bats born in captivity (naïve bats), naïve bats were inoculated intramuscularly with one of two Eptesicus fuscus rabies virus variants, EfV1 or EfV2. To determine the host response to a heterologous RABV, a separate group of naïve bats were inoculated with a Lasionycteris noctivagans RABV (LnV1). Six months following the first inoculation, all bats were challenged with EfV2. Our results indicate that naïve bats may have some level of innate resistance to intramuscular RABV inoculation. Additionally, naïve bats inoculated with the LnV demonstrated the lowest clinical infection rate of all groups. However, primary inoculation with EfV1 or LnV did not appear to be protective against a challenge with the more pathogenic EfV2.
PMCID: PMC3669413  PMID: 23741396
7.  Rabies Risk: Difficulties Encountered during Management of Grouped Cases of Bat Bites in 2 Isolated Villages in French Guiana 
In French Guiana, from 1984 to 2011, 14 animal rabies cases and 1 human rabies case (2008) were diagnosed. In January 2011, vampire-bat attacks occurred in 2 isolated villages. In mid-January, a medical team from the Cayenne Centre for Anti-Rabies Treatment visited the sites to manage individuals potentially exposed to rabies and, in April, an anti-rabies vaccination campaign for dogs was conducted. Twenty individuals were bitten by bats in 1 month, most frequently on the feet. The median time to start management was 15 days. The complete Zagreb vaccination protocol (2 doses on day 0 and 1 dose on days 7 and 21) was administered to 16 patients, 12 also received specific immunoglobulins. The antibody titration was obtained for 12 patients (different from those who received immunoglobulins). The antibody titers were ≥0.5 EU/mL for all of them. The serology has not been implemented for the 12 patients who received immunoglobulins. Accidental destruction of a vampire-bat colony could be responsible for the attacks. The isolation and absence of sensitization of the populations were the main explanations for the management difficulties encountered. Sensitization programs should be conducted regularly.
Author Summary
Rabies is a disease almost invariably fatal in humans once the first clinical signs appear. In French Guiana bats represent the virus reservoir, especially vampire bats. From 1984 to 2011, 14 animal rabies cases and 1 human rabies case (2008) were diagnosed. In case of bat bite, anti-rabies immunoglobulins (RIG) and rabies vaccine must be rapidly administrated. The specific rabies management is exclusively performed by Centre for Anti-Rabies Treatment (CART), located at the Institut Pasteur in Cayenne, the prefecture of French Guiana, and 6 Anti-Rabies Treatment Outposts distributed along the coastal edge and along the two main rivers. Only a CART physician can administer RIG. In January 2011, vampire-bat attacks occurred in 2 isolated villages. In mid-January, a medical team from the CART visited the sites to manage individuals potentially exposed to rabies and, in April, an anti-rabies vaccination campaign for dogs was conducted. The most relevant contribution of this study is to underline difficulties to provide rabies post-exposure prophylaxis to remote populations exposed to bat rabies in the Amazonian region and to show the lack of awareness of these rural populations concerning rabies and the risk associated to vampire bats.
PMCID: PMC3694830  PMID: 23826400
8.  Bat rabies surveillance in Finland 
In 1985, a bat researcher in Finland died of rabies encephalitis caused by European bat lyssavirus type 2 (EBLV-2), but an epidemiological study in 1986 did not reveal EBLV-infected bats. In 2009, an EBLV-2-positive Daubenton’s bat was detected. The EBLV-2 isolate from the human case in 1985 and the isolate from the bat in 2009 were genetically closely related. In order to assess the prevalence of EBLVs in Finnish bat populations and to gain a better understanding of the public health risk that EBLV-infected bats pose, a targeted active surveillance project was initiated.
Altogether, 1156 bats of seven species were examined for lyssaviruses in Finland during a 28–year period (1985–2012), 898 in active surveillance and 258 in passive surveillance, with only one positive finding of EBLV-2 in a Daubenton’s bat in 2009. In 2010–2011, saliva samples from 774 bats of seven species were analyzed for EBLV viral RNA, and sera from 423 bats were analyzed for the presence of bat lyssavirus antibodies. Antibodies were detected in Daubenton’s bats in samples collected from two locations in 2010 and from one location in 2011. All seropositive locations are in close proximity to the place where the EBLV-2 positive Daubenton’s bat was found in 2009. In active surveillance, no EBLV viral RNA was detected.
These data suggest that EBLV-2 may circulate in Finland, even though the seroprevalence is low. Our results indicate that passive surveillance of dead or sick bats is a relevant means examine the occurrence of lyssavirus infection, but the number of bats submitted for laboratory analysis should be higher in order to obtain reliable information on the lyssavirus situation in the country.
PMCID: PMC3846527  PMID: 24011337
EBLV; Lyssavirus; Rabies; Seroprevalence
9.  Isolation of Irkut Virus from a Murina leucogaster Bat in China 
Background and objectives
Bats are recognized as a major reservoir of lyssaviruses; however, no bat lyssavirus has been isolated in Asia except for Aravan and Khujand virus in Central Asia. All Chinese lyssavirus isolates in previous reports have been of species rabies virus, mainly from dogs. Following at least two recent bat-associated human rabies-like cases in northeast China, we have initiated a study of the prevalence of lyssaviruses in bats in Jilin province and their public health implications. A bat lyssavirus has been isolated and its pathogenicity in mice and genomic alignment have been determined.
We report the first isolation of a bat lyssavirus in China, from the brain of a northeastern bat, Murina leucogaster. Its nucleoprotein gene shared 92.4%/98.9% (nucleotide) and 92.2%/98.8% (amino acid) identity with the two known Irkut virus isolates from Russia, and was designated IRKV-THChina12. Following intracranial and intramuscular injection, IRKV-THChina12 produced rabies-like symptoms in adult mice with a short inoculation period and high mortality. Nucleotide sequence analysis showed that IRKV-THChina12 has the same genomic organization as other lyssaviruses and its isolation provides an independent origin for the species IRKV.
We have identified the existence of a bat lyssavirus in a common Chinese bat species. Its high pathogenicity in adult mice suggests that public warnings and medical education regarding bat bites in China should be increased, and that surveillance be extended to provide a better understanding of Irkut virus ecology and its significance for public health.
Author Summary
The Lyssavirus genus presently comprises 12 species and two unapproved species with different antigenic characteristics. Rabies virus is detectable worldwide; Lagos bat virus, Mokola virus, Duvenhage virus, Shimoni bat virus, and Ikoma lyssavirus circulate in Africa; European bat lyssavirus types 1 and 2, Irkut virus, West Caucasian bat virus, and Bokeloh bat lyssavirus are found in Europe; and Australian bat lyssavirus has been isolated in Australia. Only Aravan and Khujand viruses have been identified in central Asia. Bats are recognized as the most important reservoirs of lyssaviruses. In China, all lyssavirus isolates in previous reports have been rabies virus, mainly from dogs; none has been from bats. Recently, however, at least two bat-associated human rabies or rabies-like cases have been reported in northeast China. Therefore, we conducted a search for bat lyssaviruses in Jilin province, close to where the first bat-associated human rabies case was recorded. We isolated a bat lyssavirus, identified as an Irkut virus isolate with high pathogenicity in experimental mice. Our findings suggest that public warnings and medical education regarding bat bites in China should be increased, and that surveillance should be extended to provide a better understanding of Irkut virus ecology and its significance for public health.
PMCID: PMC3591329  PMID: 23505588
10.  Intravenous Inoculation of a Bat-Associated Rabies Virus Causes Lethal Encephalopathy in Mice through Invasion of the Brain via Neurosecretory Hypothalamic Fibers 
PLoS Pathogens  2009;5(6):e1000485.
The majority of rabies virus (RV) infections are caused by bites or scratches from rabid carnivores or bats. Usually, RV utilizes the retrograde transport within the neuronal network to spread from the infection site to the central nervous system (CNS) where it replicates in neuronal somata and infects other neurons via trans-synaptic spread. We speculate that in addition to the neuronal transport of the virus, hematogenous spread from the site of infection directly to the brain after accidental spill over into the vascular system might represent an alternative way for RV to invade the CNS. So far, it is unknown whether hematogenous spread has any relevance in RV pathogenesis. To determine whether certain RV variants might have the capacity to invade the CNS from the periphery via hematogenous spread, we infected mice either intramuscularly (i.m.) or intravenously (i.v.) with the dog-associated RV DOG4 or the silver-haired bat-associated RV SB. In addition to monitoring the progression of clinical signs of rabies we used immunohistochemistry and quantitative reverse transcription polymerase chain reaction (qRT-PCR) to follow the spread of the virus from the infection site to the brain. In contrast to i.m. infection where both variants caused a lethal encephalopathy, only i.v. infection with SB resulted in the development of a lethal infection. While qRT-PCR did not reveal major differences in virus loads in spinal cord or brain at different times after i.m. or i.v. infection of SB, immunohistochemical analysis showed that only i.v. administered SB directly infected the forebrain. The earliest affected regions were those hypothalamic nuclei, which are connected by neurosecretory fibers to the circumventricular organs neurohypophysis and median eminence. Our data suggest that hematogenous spread of SB can lead to a fatal encephalopathy through direct retrograde invasion of the CNS at the neurovascular interface of the hypothalamus-hypophysis system. This alternative mode of virus spread has implications for the post exposure prophylaxis of rabies, particularly with silver-haired bat-associated RV.
Author Summary
Rabies virus (RV) infects mammalian neurons and cycles in regionally distinct animal populations such as the red fox in Europe, domestic canines in Asia, or raccoons, skunks and bats in Northern America. Although human rabies can be prevented by pre- and post-exposure prophylaxis, more than 50,000 people die annually from the severe encephalopathy caused by RV. Recently, two cases of RV transmission by organ transplantation were reported. In our study, using intravenous inoculation of mice, we evaluated the pathogenetic relevance of virions that reach the bloodstream. Mice inoculated intravenously with a canine-derived RV survived the infection in contrast to intramuscularly injected mice, while mice infected with a silver-haired bat-related RV succumbed to the disease regardless of the route of inoculation. We found that the silver-haired bat-related RV was able to transit from the blood to the brain by invading neurosecretory fibers of the hypothalamus, which form neurohemal synapses lacking a blood-brain-barrier. This newly described route of brain invasion might reflect how RV reached the central nervous system from transplanted organs, since it takes longer to establish the neural connections between host and grafted tissue necessary for classical RV migration than the time until the infection became symptomatic in the two reported cases.
PMCID: PMC2691950  PMID: 19543379
11.  15O PET Measurement of Blood Flow and Oxygen Consumption in Cold-Activated Human Brown Fat 
Although it has been believed that brown adipose tissue (BAT) depots disappear shortly after the perinatal period in humans, PET imaging using the glucose analog 18F-FDG has shown unequivocally the existence of functional BAT in adult humans, suggesting that many humans retain some functional BAT past infancy. The objective of this study was to determine to what extent BAT thermogenesis is activated in adults during cold stress and to establish the relationship between BAT oxidative metabolism and 18F-FDG tracer uptake.
Twenty-five healthy adults (15 women and 10 men; mean age ± SD, 30 ± 7 y) underwent triple-oxygen scans (H215O, C15O, and 15O2) as well as measurements of daily energy expenditure (DEE; kcal/d) both at rest and after exposure to mild cold (15.5°C [60°F]) using indirect calorimetry. The subjects were divided into 2 groups (high BAT and low BAT) based on the presence or absence of 18F-FDG tracer uptake (standardized uptake value [SUV] > 2) in cervical–supraclavicular BAT. Blood flow and oxygen extraction fraction (OEF) were calculated from dynamic PET scans at the location of BAT, muscle, and white adipose tissue. Regional blood oxygen saturation was determined by near-infrared spectroscopy. The total energy expenditure during rest and mild cold stress was measured by indirect calorimetry. Tissue-level metabolic rate of oxygen (MRO2) in BAT was determined and used to calculate the contribution of activated BAT to DEE.
The mass of activated BAT was 59.1 ± 17.5 g (range, 32–85 g) in the high-BAT group (8 women and 1 man; mean age, 29.6 ± 5.5 y) and 2.2 ± 3.6 g (range, 0–9.3 g) in the low-BAT group (9 men and 7 women; mean age, 31.4 ± 10 y). Corresponding maximal SUVs were significantly higher in the high-BAT group than in the low-BAT group (10.7 ± 3.9 vs. 2.1 ± 0.7, P = 0.01). Blood flow values were significantly higher in the high-BAT group than in the low-BAT group for BAT (12.9 ± 4.1 vs. 5.9 ± 2.2 mL/100 g/min, P = 0.03) and white adipose tissue (7.2 ± 3.4 vs. 5.7 ± 2.3 mL/100 g/min, P = 0.03) but were similar for muscle (4.4 ± 1.9 vs. 3.9 ± 1.7 mL/100 g/min). Moreover, OEF in BAT was similar in the 2 groups (0.51 ± 0.17 in high-BAT group vs. 0.47 ± 0.18 in low-BAT group, P = 0.39). During mild cold stress, calculated MRO2 values in BAT increased from 0.97 ± 0.53 to 1.42 ± 0.68 mL/100 g/min (P = 0.04) in the high-BAT group and were significantly higher than those determined in the low-BAT group (0.40 ± 0.28 vs. 0.51 ± 0.23, P = 0.67). The increase in DEE associated with BAT oxidative metabolism was highly variable in the high-BAT group, with an average of 3.2 ± 2.4 kcal/d (range, 1.9–4.6 kcal/d) at rest, and increased to 6.3 ± 3.5 kcal/d (range, 4.0–9.9 kcal/d) during exposure to mild cold. Although BAT accounted for only a small fraction of the cold-induced increase in DEE, such increases were not observed in subjects lacking BAT.
Mild cold-induced thermogenesis in BAT accounts for 15–25 kcal/d in subjects with relatively large BAT depots. Thus, although the presence of active BAT is correlated with cold-induced energy expenditure, direct measurement of MRO2 indicates that BAT is a minor source of thermogenesis in humans.
PMCID: PMC3883579  PMID: 23362317
brown fat thermogenesis; BAT oxidative metabolism; 15O PET imaging
12.  Changes in Knowledge of Bat Rabies and Human Exposure among United States Cavers 
The purpose of the study was to evaluate changes in the knowledge of bat rabies and human exposure among United States cavers during the last decade. A survey was distributed among cavers who attended the National Speleological Society convention in 2000 and those who attended in 2010. In 2000 and 2010, 392 and 108 cavers, respectively, responded to the questionnaire. Eighty-five per cent of respondents in 2000 indicated a bat bite as a risk for rabies compared with all respondents in 2010 (P < 0.0001 controlling for age). The proportion of respondents indicating that they were advised to receive rabies pre-exposure prophylaxis (PreEP) because of caving increased (17% and 29%; P = 0.03 controlling for age). Among these, PreEP was received by 56% and 45%. Although recognition of the risk of rabies exposure from bats is important, the proportion of cavers acting on current recommendations regarding PreEP does not appear to have improved in the past decade.
PMCID: PMC3919228  PMID: 24297813
13.  Assessment of Oxidative Metabolism in Brown Fat Using PET Imaging 
Objective: Although it has been believed that brown adipose tissue (BAT) depots disappear shortly after the perinatal period in humans, positron emission tomography (PET) imaging using the glucose analog 18F-deoxy-d-glucose (FDG) has shown unequivocally the existence of functional BAT in humans, suggesting that most humans have some functional BAT. The objective of this study was to determine, using dynamic oxygen-15 (15O) PET imaging, to what extent BAT thermogenesis is activated in adults during cold stress and to establish the relationship between BAT oxidative metabolism and FDG tracer uptake. Methods: Fourteen adult normal subjects (9F/5M, 30 ± 7 years) underwent triple oxygen scans (H215O, C15O, 15O2) as well as indirect calorimetric measurements at both rest and following exposure to mild cold (16°C). Subjects were divided into two groups (BAT+ and BAT−) based on the presence or absence of FDG tracer uptake (SUV > 2) in cervical–supraclavicular BAT. Blood flow and oxygen extraction fraction (OEF) was calculated from dynamic PET scans at the location of BAT, muscle, and white adipose tissue (WAT). The metabolic rate of oxygen (MRO2) in BAT was determined and used to calculate the contribution of activated BAT to daily energy expenditure (DEE). Results: The median mass of activated BAT in the BAT+ group (5F, age 31 ± 8) was 52.4 g (range 14–68 g) and was 1.7 g (range 0–6.3 g) in the BAT − group (5M/4F, age 29 ± 6). Corresponding SUV values were significantly higher in the BAT+ as compared to the BAT− group (7.4 ± 3.7 vs. 1.9 ± 0.9; p = 0.03). Blood flow values in BAT were significantly higher in the BAT+ group as compared to the BAT− group (13.1 ± 4.4 vs. 5.7 ± 1.1 ml/100 g/min, p = 0.03), but were similar in WAT (4.1 ± 1.6 vs. 4.2 ± 1.8 ml/100 g/min) and muscle (3.7 ± 0.8 vs. 3.3 ± 1.2 ml/100 g/min). Moreover, OEF in BAT was similar in the two groups (0.56 ± 0.18 in BAT+ vs. 0.46 ± 0.19 in BAT−, p = 0.39). Calculated MRO2 values in BAT increased from 0.95 ± 0.74 to 1.62 ± 0.82 ml/100 g/min in the BAT+ group and were significantly higher than those determined in the BAT− group (0.43 ± 0.27 vs. 0.56 ± 0.24, p = 0.67). The DEE associated with BAT oxidative metabolism was highly variable in the BAT+ group, with an average of 5.5 ± 6.4 kcal/day (range 0.57–15.3 kcal/day). Conclusion: BAT thermogenesis in humans accounts for less than 20 kcal/day during moderate cold stress, even in subjects with relatively large BAT depots. Furthermore, due to the large differences in blood flow and glucose metabolic rates in BAT between humans and rodents, the application of rodent data to humans is problematic and needs careful evaluation.
PMCID: PMC3355936  PMID: 22649408
brown fat thermogenesis; oxidative metabolism; 15O PET imaging
14.  First Human Rabies Case in French Guiana, 2008: Epidemiological Investigation and Control 
Until 2008, human rabies had never been reported in French Guiana. On 28 May 2008, the French National Reference Center for Rabies (Institut Pasteur, Paris) confirmed the rabies diagnosis, based on hemi-nested polymerase chain reaction on skin biopsy and saliva specimens from a Guianan, who had never travelled overseas and died in Cayenne after presenting clinically typical meningoencephalitis.
Methodology/Principal Findings
Molecular typing of the virus identified a Lyssavirus (Rabies virus species), closely related to those circulating in hematophagous bats (mainly Desmodus rotundus) in Latin America. A multidisciplinary Crisis Unit was activated. Its objectives were to implement an epidemiological investigation and a veterinary survey, to provide control measures and establish a communications program. The origin of the contamination was not formally established, but was probably linked to a bat bite based on the virus type isolated. After confirming exposure of 90 persons, they were vaccinated against rabies: 42 from the case's entourage and 48 healthcare workers. To handle that emergence and the local population's increased demand to be vaccinated, a specific communications program was established using several media: television, newspaper, radio.
This episode, occurring in the context of a Department far from continental France, strongly affected the local population, healthcare workers and authorities, and the management team faced intense pressure. This observation confirms that the risk of contracting rabies in French Guiana is real, with consequences for population educational program, control measures, medical diagnosis and post-exposure prophylaxis.
Author Summary
Until 2008, rabies had never been described within the French Guianan human population. Emergence of the first case in May 2008 in this French Overseas Department represented a public health event that markedly affected the local population, healthcare workers and public health authorities. The antirabies clinic of French Guiana, located at Institut Pasteur de la Guyane, had to reorganize its functioning to handle the dramatically increased demand for vaccination. A rigorous epidemiological investigation and a veterinary study were conducted to identify the contamination source, probably linked to a bat bite, and the exposed population. Communication was a key factor to controlling this episode and changing the local perception of this formerly neglected disease. Because similar clinical cases had previously been described, without having been diagnosed, medical practices must be adapted and the rabies virus should be sought more systematically in similarly presenting cases. Sharing this experience could be useful for other countries that might someday have to manage such an emergence.
PMCID: PMC3283561  PMID: 22363830
15.  Host immunity to repeated rabies virus infection in big brown bats 
The Journal of General Virology  2010;91(Pt 9):2360-2366.
Bats are natural reservoirs for the majority of lyssaviruses globally, and are unique among mammals in having exceptional sociality and longevity. Given these facets, and the recognized status of bats as reservoirs for rabies viruses (RABVs) in the Americas, individual bats may experience repeated exposure to RABV during their lifetime. Nevertheless, little information exists with regard to within-host infection dynamics and the role of immunological memory that may result from abortive RABV infection in bats. In this study, a cohort of big brown bats (Eptesicus fuscus) was infected intramuscularly in the left and right masseter muscles with varying doses [10−0.1–104.9 median mouse intracerebral lethal doses (MICLD50)] of an E. fuscus RABV variant isolated from a naturally infected big brown bat. Surviving bats were infected a second time at 175 days post-(primary) infection with a dose (103.9–104.9 MICLD50) of the same RABV variant. Surviving bats were infected a third time at either 175 or 305 days post-(secondary) infection with a dose (104.9 MICLD50) of the same RABV variant. When correcting for dose, similar mortality was observed following primary and secondary infection, but reduced mortality was observed following the third and last RABV challenge, despite infection with a high viral dose. Inducible RABV-neutralizing antibody titres post-infection were ephemeral among infected individuals, and dropped below levels of detection in several bats between subsequent infections. These results suggest that long-term repeated infection of bats may confer significant immunological memory and reduced susceptibility to RABV infection.
PMCID: PMC3052523  PMID: 20519458
16.  Rabies Postexposure Prophylaxis, New York, 1995–2000 
Emerging Infectious Diseases  2005;11(12):1921-1927.
Bats are now the leading source of rabies postexposure prophylaxis.
The epidemiology of human rabies postexposure prophylaxis (PEP) in 4 upstate New York counties was described from data obtained from 2,216 incidences of PEP recorded by local health departments from 1995 to 2000. Overall annual incidence for the study period was 27 cases per 100,000 persons. Mean annual PEP incidence rates were highest in rural counties and during the summer months. PEP incidence was highest among patients 5–9 and 30–34 years of age. Bites accounted for most PEP (51%) and were primarily associated with cats and dogs. Bats accounted for 30% of exposures, more than any other group of animals; consequently, bats have replaced raccoons as the leading rabies exposure source to humans in this area.
PMCID: PMC3367620  PMID: 16485480
Rabies; epidemiology; animal exposure; vaccination; zoonoses; research
17.  Bat Rabies in Guatemala 
Rabies in bats is considered enzootic throughout the New World, but few comparative data are available for most countries in the region. As part of a larger pathogen detection program, enhanced bat rabies surveillance was conducted in Guatemala, between 2009 and 2011. A total of 672 bats of 31 species were sampled and tested for rabies. The prevalence of rabies virus (RABV) detection among all collected bats was low (0.3%). Viral antigens were detected and infectious virus was isolated from the brains of two common vampire bats (Desmodus rotundus). RABV was also isolated from oral swabs, lungs and kidneys of both bats, whereas viral RNA was detected in all of the tissues examined by hemi-nested RT-PCR except for the liver of one bat. Sequencing of the nucleoprotein gene showed that both viruses were 100% identical, whereas sequencing of the glycoprotein gene revealed one non-synonymous substitution (302T,S). The two vampire bat RABV isolates in this study were phylogenetically related to viruses associated with vampire bats in the eastern states of Mexico and El Salvador. Additionally, 7% of sera collected from 398 bats demonstrated RABV neutralizing antibody. The proportion of seropositive bats varied significantly across trophic guilds, suggestive of complex intraspecific compartmentalization of RABV perpetuation.
Author Summary
In this study we provide results of the first active and extensive surveillance effort for rabies virus (RABV) circulation among bats in Guatemala. The survey included multiple geographic areas and multiple species of bats, to assess the broader public and veterinary health risks associated with rabies in bats in Guatemala. RABV was isolated from vampire bats (Desmodus rotundus) collected in two different locations in Guatemala. Sequencing of the isolates revealed a closer relationship to Mexican and Central American vampire bat isolates than to South American isolates. The detection of RABV neutralizing antibodies in 11 species, including insectivorous, frugivorous, and sanguivorous bats, demonstrates viral circulation in both hematophagous and non-hematophagous bat species in Guatemala. The presence of bat RABV in rural communities requires new strategies for public health education regarding contact with bats, improved laboratory-based surveillance of animals associated with human exposures, and novel techniques for modern rabies prevention and control. Additionally, healthcare practitioners should emphasize the collection of a detailed medical history, including questions regarding bat exposure, for patients presenting with clinical syndromes compatible with rabies or any clinically diagnosed progressive encephalitis.
PMCID: PMC4117473  PMID: 25080103
18.  Rabies menace and control – An insight into knowledge, attitude and practices 
There are very few community-based epidemiological studies on knowledge, attitude and practice about rabies prevention and control. This cross-sectional study was undertaken to determine the same in an urban slum area.
A random sample of 200 people was selected from an urban slum area. A pre-tested pro-forma was used to collect the data.
All study participants had knowledge of rabies transmission by dog bite compared to only 23% having knowledge about its transmission by scratches and licks. Only 40% of the participants were aware that the disease would cause fatal illness. As a first aid measure after dog bite, 66% of the participants responded that they would wash the wound with water, 24% said that they would visit a doctor and the rest responded that either they would do nothing (3%) or would adopt some unconventional methods/religious practices (7%) to prevent the development of rabies. 55.5% of participants were aware about the role of vaccine in preventing rabies.
The level of awareness about rabies and its control measures is not high. The attitudes and practices of the respondents reflect the lack of IEC activities, inaccessibility of treatment facilities and the lack of services that would enable community participation in rabies control.
PMCID: PMC3862780  PMID: 24532936
Knowledge; Attitude; Practice; Rabies; Urban slum area
19.  Ecology of Rabies Virus Exposure in Colonies of Brazilian Free-Tailed Bats (Tadarida brasiliensis) at Natural and Man-Made Roosts in Texas 
Previous studies have investigated rabies virus (RABV) epizootiology in Brazilian free-tailed bats (Tadarida brasiliensis) in natural cave roosts. However, little is known about geographic variation in RABV exposure, or if the use of man-made roosts by this species affects enzootic RABV infection dynamics within colonies. We sampled rabies viral neutralizing antibodies in bats at three bridge and three cave roosts at multiple time points during the reproductive season to investigate temporal and roost variation in RABV exposure. We report seropositive bats in all age and sex classes with minimal geographic variation in RABV seroprevalence among Brazilian free-tailed bat colonies in south-central Texas. While roost type was not a significant predictor of RABV seroprevalence, it was significantly associated with seasonal fluctuations, suggesting patterns of exposure that differ between roosts. Temporal patterns suggest increased RABV seroprevalence after parturition in cave colonies, potentially related to an influx of susceptible young, in contrast to more uniform seroprevalence in bridge colonies. This study highlights the importance of life history and roost ecology in understanding patterns of RABV seroprevalence in colonies of the Brazilian free-tailed bat.
PMCID: PMC2944840  PMID: 19492942
Brazilian free-tailed bat; Epizootiology; Rabies virus; Roost ecology
20.  Rabies Exposures, Post-Exposure Prophylaxis and Deaths in a Region of Endemic Canine Rabies 
Thousands of human deaths from rabies occur annually despite the availability of effective vaccines following exposure, and for disease control in the animal reservoir. Our aim was to assess risk factors associated with exposure and to determine why human deaths from endemic canine rabies still occur.
Methods and Findings
Contact tracing was used to gather data on rabies exposures, post-exposure prophylaxis (PEP) delivered and deaths in two rural districts in northwestern Tanzania from 2002 to 2006. Data on risk factors and the propensity to seek and complete courses of PEP was collected using questionnaires. Exposures varied from 6–141/100,000 per year. Risk of exposure to rabies was greater in an area with agropastoralist communities (and larger domestic dog populations) than an area with pastoralist communities. Children were at greater risk than adults of being exposed to rabies and of developing clinical signs. PEP dramatically reduced the risk of developing rabies (odds ratio [OR] 17.33, 95% confidence interval [CI] 6.39–60.83) and when PEP was not delivered the risks were higher in the pastoralist than the agro-pastoralist area (OR 6.12, 95% CI 2.60–14.58). Low socioeconomic class and distance to medical facilities lengthened delays before PEP delivery. Over 20% of rabies-exposed individuals did not seek medical treatment and were not documented in official records and <65% received PEP. Animal bite injury records were an accurate indicator of rabies exposure incidence.
Insufficient knowledge about rabies dangers and prevention, particularly prompt PEP, but also wound management, was the main cause of rabies deaths. Education, particularly in poor and marginalized communities, but also for medical and veterinary workers, would prevent future deaths.
Author Summary
Thousands of human deaths from rabies occur annually despite availability of effective vaccines for humans following exposure, and for disease control in domestic dog populations. We established a 5-year contact-tracing study in northwest Tanzania to investigate risk factors associated with rabies exposure and to determine why human deaths from canine rabies still occur. We found that children were at greater risk of being bitten and of developing rabies than adults and that incidence of bites by suspected rabid animals was higher in an area with larger domestic dog populations. A large proportion (>20%) of those bitten by rabid animals are not recorded in official records because they do not seek post-exposure prophylaxis (PEP), which is crucial for preventing the onset of rabies. Of those that seek medical attention, a significant proportion do not receive PEP because of the expense or because of hospital shortages; and victims who are poorer, and who live further from medical facilities, typically experience greater delays before obtaining PEP. Our work highlights the need to raise awareness about rabies dangers and prevention, particularly prompt PEP, but also wound management. We outline practical recommendations to prevent future deaths, stressing the importance of education, particularly in poor and marginalized communities, as well as for medical and veterinary workers.
PMCID: PMC2582685  PMID: 19030223
21.  Dog Bites in Humans and Estimating Human Rabies Mortality in Rabies Endemic Areas of Bhutan 
Dog bites in humans are a public health problem worldwide. The issues of increasing stray dog populations, rabies outbreaks, and the risk of dogs biting humans have been frequently reported by the media in Bhutan. This study aimed to estimate the bite incidence and identify the risk factors for dog bites in humans, and to estimate human deaths from rabies in rabies endemic south Bhutan.
A hospital-based questionnaire survey was conducted during 2009–2010 among dog bites victims who visited three hospitals in Bhutan for anti-rabies vaccine injection. Decision tree modeling was used to estimate human deaths from rabies following dog bite injuries in two rabies endemic areas of south Bhutan.
Three hundred and twenty four dog bite victims were interviewed. The annual incidence of dog bites differed between the hospital catchment areas: 869.8 (95% CI: 722.8–1022.5), 293.8 (240–358.2) and 284.8 (251.2–323) per 100,000 people in Gelephu, Phuentsholing and Thimphu, respectively. Males (62%) were more at risk than females (P<0.001). Children aged 5–9 years were bitten more than other age groups. The majority of victims (71%) were bitten by stray dogs. No direct fatal injury was reported. In two hospital areas (Gelephu and Phuentsholing) in south Bhutan the annual incidence of death from rabies was 3.14 (95% CI: 1.57–6.29) per 100,000 population. The decision tree model predicted an equivalent annual incidence of 4.67 (95% CI: 2.53–7.53) deaths/100,000 population at risk. In the absence of post exposure prophylaxis, the model predicted 19.24 (95% CI: 13.69–25.14) deaths/year in these two areas.
Increased educational awareness of people about the risk of dog bites and rabies is necessary, particularly for children in rabies endemic areas of Bhutan.
Author Summary
Dog bites in humans are a public health problem worldwide. We conducted a hospital based questionnaire survey and described the incidence and risk factors for human dog bites in Bhutan. We also estimated the human death rate attributable to rabies in two rabies endemic areas of south Bhutan. Our study shows that dog bites incidents in humans are common in the survey areas. There were significant gender and age differences in bite incidents; males and the children are affected the most. The majority of the victims were bitten by stray dogs, increasing the risk of rabies infection if not treated in time. Our decision tree model predicted 2.23 (95% CI: 1.20–3.59) human deaths from rabies/year, equivalent to an annual incidence of 4.67 (95% CI: 2.53–7.53) deaths/100,000 in the two rabies endemic areas of south Bhutan. In the absence of post exposure prophylaxis, the model predicted 19.24 (95% CI: 13.69–25.14) deaths/year in these two areas. The public should be encouraged to visit hospitals for post exposure prophylaxis following dog bite injury in south Bhutan.
PMCID: PMC3222627  PMID: 22132247
22.  Bat Rabies in France: A 24-Year Retrospective Epidemiological Study 
PLoS ONE  2014;9(6):e98622.
Since bat rabies surveillance was first implemented in France in 1989, 48 autochthonous rabies cases without human contamination have been reported using routine diagnosis methods. In this retrospective study, data on bats submitted for rabies testing were analysed in order to better understand the epidemiology of EBLV-1 in bats in France and to investigate some epidemiological trends. Of the 3176 bats submitted for rabies diagnosis from 1989 to 2013, 1.96% (48/2447 analysed) were diagnosed positive. Among the twelve recognised virus species within the Lyssavirus genus, two species were isolated in France. 47 positive bats were morphologically identified as Eptesicus serotinus and were shown to be infected by both the EBLV-1a and the EBLV-1b lineages. Isolation of BBLV in Myotis nattereri was reported once in the north-east of France in 2012. The phylogenetic characterisation of all 47 French EBLV-1 isolates sampled between 1989 and 2013 and the French BBLV sample against 21 referenced partial nucleoprotein sequences confirmed the low genetic diversity of EBLV-1 despite its extensive geographical range. Statistical analysis performed on the serotine bat data collected from 1989 to 2013 showed seasonal variation of rabies occurrence with a significantly higher proportion of positive samples detected during the autumn compared to the spring and the summer period (34% of positive bats detected in autumn, 15% in summer, 13% in spring and 12% in winter). In this study, we have provided the details of the geographical distribution of EBLV-1a in the south-west of France and the north-south division of EBLV-1b with its subdivisions into three phylogenetic groups: group B1 in the north-west, group B2 in the centre and group B3 in the north-east of France.
PMCID: PMC4044004  PMID: 24892287
23.  Implementation of an Intersectoral Program to Eliminate Human and Canine Rabies: The Bohol Rabies Prevention and Elimination Project 
The province of Bohol, located in the Visayas islands region in the Philippines has a human population of 1.13 million and was the 4th highest region for human rabies deaths in the country, averaging 10 per year, prior to the initiation of the Bohol Rabies Prevention and Elimination Project (BRPEP).
The BRPEP was initiated in 2007 with the goal of building a sustainable program that would prevent human rabies by eliminating rabies at its source, in dogs, by 2010. This goal was in line with the Philippine National Rabies Program whose objective is to eliminate rabies by 2020.
The intersectoral BRPEP was launched in 2007 and integrated the expertise and resources from the sectors of agriculture, public health and safety, education, environment, legal affairs, interior and local government. The program included: increasing local community involvement; implementing dog population control; conducting mass dog vaccination; improving dog bite management; instituting veterinary quarantine; and improving diagnostic capability, surveillance and monitoring. Funding was secured from the national government, provincial, municipal and village units, dog owners, NGOs, the regional office of the WHO, the UBS Optimus Foundation, and the Global Alliance for Rabies Control. The BRPEP was managed by the Bohol Rabies Prevention and Eradication Council (BRPEC) under the jurisdiction of the Governor of Bohol. Parallel organizations were created at the municipal level and village level. Community volunteers facilitated the institution of the program. Dog population surveys were conducted to plan for sufficient resources to vaccinate the required 70% of the dogs living in the province. Two island-wide mass vaccination campaigns were conducted followed by “catch up” vaccination campaigns. Registration of dogs was implemented including a small fee that was rolled back into the program to maintain sustainability. Children were educated by introducing rabies prevention modules into all elementary schools in Bohol. Existing public health legislation at the national, provincial, and municipal level strengthened the enforcement of activities. A Knowledge, Attitude and Practices (KAP) survey was conducted in 2009 to evaluate the educational knowledge of the population. Increased surveillance was instituted to ensure that dogs traveling into and out of the province were vaccinated against rabies. Human and animal cases of rabies were reported to provincial and national authorities.
Key Results
Within the first 18 months of the BRPEP, human rabies deaths had decreased annually from 0.77 to 0.37 to zero per 100,000 population from 2007–2009. Between October 2008 and November 2010 no human and animal cases were detected. Increased surveillance on the island detected one suspected human rabies case in November 2010 and one confirmed case of canine rabies in April 2011. Two mass vaccination campaigns conducted in 2007 and 2008 successfully registered and vaccinated 44% and 70% of the dogs on the island. The additional surveillance activities enabled a mobilization of mop up vaccination activities in the region where the human and canine case was located. Due to the increased effective and continuous surveillance activities, rabies was stopped before it could spread to other areas on the island. The program costs totaled USD 450,000. Registration fees collected to maintain the program amounted to USD 105,740 and were re-allocated back into the community to sustain the program.
Author Summary
The Province of Bohol, Philippines has eliminated dog and human rabies in less than three years by empowering the community and implementing an intersectoral strategy. In 2006, Bohol ranked 4th highest in the Philippines for human rabies, averaging 10 deaths per year. Launched in 2007, the program utilized a social awareness campaign, dog population control, mass dog vaccination campaigns, improved dog bite management and veterinary quarantine, a new diagnostic laboratory, expanded surveillance, and the inclusion of education modules into the school curriculum. Improving community compliance to existing national and provincial rabies laws and engaging volunteers to help conduct the project was a key to success. The program, led by the Governor of Bohol, was administered through a group of departments working together at a provincial and local level, and supervised through the Office of the Provincial Veterinarian. Financial support came through the Governor and several NGOs including the Global Alliance for Rabies Control. The program is self-sustaining, through a small dog registration fee fed back into the program, through the continuing education of children in their classrooms, and through the dedicated efforts of over 15,000 staff and volunteers throughout the island.
PMCID: PMC3516573  PMID: 23236525
24.  High Diversity of Rabies Viruses Associated with Insectivorous Bats in Argentina: Presence of Several Independent Enzootics 
Rabies is a fatal infection of the central nervous system primarily transmitted by rabid animal bites. Rabies virus (RABV) circulates through two different epidemiological cycles: terrestrial and aerial, where dogs, foxes or skunks and bats, respectively, act as the most relevant reservoirs and/or vectors. It is widely accepted that insectivorous bats are not important vectors of RABV in Argentina despite the great diversity of bat species and the extensive Argentinean territory.
We studied the positivity rate of RABV detection in different areas of the country, and the antigenic and genetic diversity of 99 rabies virus (RABV) strains obtained from 14 species of insectivorous bats collected in Argentina between 1991 and 2008.
Based on the analysis of bats received for RABV analysis by the National Rabies system of surveillance, the positivity rate of RABV in insectivorous bats ranged from 3.1 to 5.4%, depending on the geographic location. The findings were distributed among an extensive area of the Argentinean territory. The 99 strains of insectivorous bat-related sequences were divided into six distinct lineages associated with Tadarida brasiliensis, Myotis spp, Eptesicus spp, Histiotus montanus, Lasiurus blosseviilli and Lasiurus cinereus. Comparison with RABV sequences obtained from insectivorous bats of the Americas revealed co-circulation of similar genetic variants in several countries. Finally, inter-species transmission, mostly related with Lasiurus species, was demonstrated in 11.8% of the samples.
This study demonstrates the presence of several independent enzootics of rabies in insectivorous bats of Argentina. This information is relevant to identify potential areas at risk for human and animal infection.
Author Summary
In Argentina, successful vaccination and control of terrestrial rabies in the 1980s revealed the importance of the aerial route in RABV transmission. Current distribution of cases shows a predominance of rabies by hematophagous bats in the Northern regions where rabies is a major public health concern; in contrast, in Central and Southern regions where rabies is not a major public health concern, little surveillance is performed. Based on the analysis of insectivorous bats received for RABV analysis by the National Rabies system of surveillance, the positivity rate of RABV in insectivorous bats in these regions ranged from 3.1 to 5.4%. This rate is comparable to other nations such as the United States (9–10%) where insectivorous bats are an important cause of concern for RABV surveillance systems. Antigenic and genetic analysis of a wide collection of rabies strains shows the presence of multiple endemic cycles associated with six bat insectivorous species distributed among an extensive area of the Argentinean territory and several countries of the Americas. Finally, inter-species transmission, mostly related with Lasiurus species, was demonstrated in 11.8% of the samples. Increased public education about the relationship between insectivorous bats and rabies are essential to avoid human cases and potential spread to terrestrial mammals.
PMCID: PMC3348165  PMID: 22590657
25.  Susceptibility and Pathogenesis of Little Brown Bats (Myotis lucifugus) to Heterologous and Homologous Rabies Viruses 
Journal of Virology  2013;87(16):9008-9015.
Rabies virus (RABV) maintenance in bats is not well understood. Big brown bats (Eptesicus fuscus), little brown bats (Myotis lucifugus), and Mexican free-tailed bats (Tadarida brasiliensis) are the most common bats species in the United States. These colonial bat species also have the most frequent contact with humans and domestic animals. However, the silver-haired bat (Lasionycteris noctivagans) RABV is associated with the majority of human rabies virus infections in the United States and Canada. This is of interest because silver-haired bats are more solitary bats with infrequent human interaction. Our goal was to determine the likelihood of a colonial bat species becoming infected with and transmitting a heterologous RABV. To ascertain the potential of heterologous RABV infection in colonial bat species, little brown bats were inoculated with a homologous RABV or one of two heterologous RABVs. Additionally, to determine if the route of exposure influenced the disease process, bats were inoculated either intramuscularly (i.m.) or subcutaneously (s.c.) with a homologous or heterologous RABV. Our results demonstrate that intramuscular inoculation results in a more rapid progression of disease onset, whereas the incubation time in bats inoculated s.c. is significantly longer. Additionally, cross protection was not consistently achieved in bats previously inoculated with a heterologous RABV following a challenge with a homologous RABV 6 months later. Finally, bats that developed rabies following s.c. inoculation were significantly more likely to shed virus in their saliva and demonstrated increased viral dissemination. In summary, bats inoculated via the s.c. route are more likely to shed virus, thus increasing the likelihood of transmission.
PMCID: PMC3754046  PMID: 23741002

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