Experimental infection of Artibeus intermedius with a vampire bat rabies virus

Experimental infection of Artibeus intermedius, the great fruit-eating bat, was performed with vampire bat rabies isolates. Bats (n = 35) were captured in the wild and quarantined prior to experimental infection. No rabies antibodies were detected by rapid fluorescent focus inhibition test (RFFIT) prior to infection. Three doses of rabies virus (RV) and three different routes of infection were used. One out of 35 bats died without showing any clinical signs at day 14 and was positive for rabies. None of the 34 other bats showed clinical signs for rabies, but high antibody titers were detected post-inoculation, suggesting either innate immune response to the vampire bat rabies virus or possible pre-exposure to RV and inoculation leading to a booster effect. Rabies virus was detected by hemi-nested RT-PCR (hnRT-PCR) in the brain (n = 3), stomach (n = 1) of bats that were negative by immunofluorescence and that survived rabies infection. The bat that died on day 14 was positive by hnRT-PCR on the brain, heart and liver. These results suggest that either previous non-lethal exposure to RV or natural low susceptibility to vampire bat viruses somehow protected Artibeus intermedius from clinical rabies infection leading to a marginal lethality effect on this bats species population in the wild.     

Lineage‐specific evolution of bitter taste receptor genes in the giant and red pandas implies dietary adaptation

Taste 2 receptors (TAS2R) mediate bitterness perception in mammals, thus are called bitter taste receptors. It is believed that these genes evolved in response to species‐specific diets. The giant panda (Ailuropoda melanoleuca) and red panda (Ailurus fulgens styani) in the order Carnivora are specialized herbivores with an almost exclusive bamboo diet (>90% bamboo). Because bamboo is full of bitter tasting compounds, we hypothesized that adaptive evolution has occurred at TAS2R genes in giant and red pandas throughout the course of their dietary shift. Here, we characterized 195 TAS2R genes in 9 Carnivora species and examined selective pressures on these genes. We found that both pandas harbor more putative functional TAS2R genes than other carnivores, and pseudogenized TAS2R genes in the giant panda are different from the red panda. The purifying selection on TAS2R1, TAS2R9 and TAS2R38 in the giant panda, and TAS2R62 in the red panda, has been strengthened throughout the course of adaptation to bamboo diet, while selective constraint on TAS2R4 and TAS2R38 in the red panda is relaxed. Remarkably, a few positively selected sites on TAS2R42 have been specifically detected in the giant panda. These results suggest an adaptive response in both pandas to a dietary shift from carnivory to herbivory, and TAS2R genes evolved independently in the 2 pandas. Our findings provide new insight into the molecular basis of mammalian sensory evolution and the process of adaptation to new ecological niches.     

Hemotropic mycoplasmas (hemoplasmas) in free-ranging bats from Southern Brazil

Hemotropic mycoplasmas (hemoplasmas) are bacteria distributed worldwide and affect domestic and wildlife animals and human beings. Hemoplasmas have been described infecting hematophagous and non-hematophagous bats; however, transmission risk and zoonotic potential in vampire bats remain to be fully established. This study aimed to evaluate the presence of hemotropic mycoplasma species in free-ranging bats from this area using a universal PCR protocol for hemoplasmas. Accordingly, ten blood samples were collected from six male common vampire bats (Desmodus rotundus), two male hairy-legged vampire bats (Diphylla ecaudata), and two female non-hematophagous Pallas's mastiff bats (Molossus sp.) from the Curitiba’s region, Paraná State, Southern Brazil. A total of eight (8/10) blood samples were positive byconventional PCR; five (5/6) Desmodus rotundus, two (2/2) Diphylla ecaudata, and one (1/2) Molossus sp. bats. The analyses of the partial sequence of the 16S rDNA gene suggest that the hemoplasma detected in Desmodus rotundus in South Brazil has a high identity compared to the hemoplasma circulating in vampire bats from Central and South America.     

Genetic characterization of rabies viruses isolated from frugivorous bat (Artibeus spp.) in Brazil

In Latin America, rabies cases related to frugivorous bats have been reported since 1930's. Recently, two viruses isolated from Artibeus lituratus were proved to be vampire bat variants by monoclonal antibodies panels [2], but their genetic information is not well known. In this report, four rabies viruses were isolated from frugivorous bats (Artibeus spp.) in Brazil and their nucleoprotein gene sequences were determined. These isolates were found to be genotype 1 of lyssavirus and showed the maximum nucleotide sequence homology of 97.6-99.4% with vampire bat-related viruses in Brazil [6]. These results indicate that the Brazilian frugivorous bat rabies viruses in this study are closely related to vampire bat-related viruses that play a main role in rabies virus transmission to livestock in Brazil.     

The rabies viruses of bats

In the 1930s rabies was shown to affect blood-, insect- and fruit-eating bats. We have prepared anti-nucleocapsid monoclonal antibodies (MAbs) using Mokola and bat (Lagos, Duvenhage and Denmark) rabies viruses as immunogens. With these MAbs we have examined rabies viruses from vampire, insectivorous and frugivorous bats from the Americas, Africa, Europe and the Soviet Union and have compared them with isolates from terrestrial species including man. As well as confirming the findings of others with viruses of African and American bat origin, the results revealed the presence of a second biotype in European bats and demonstrated the presence of serotype 1 as well as serotype 4 viruses in bats of the Soviet Union.     

Bartonellae are Prevalent and Diverse in Costa Rican Bats and Bat Flies

Species in the bacterial genus, Bartonella, can cause disease in both humans and animals. Previous reports of Bartonella in bats and ectoparasitic bat flies suggest that bats could serve as mammalian hosts and bat flies as arthropod vectors. We compared the prevalence and genetic similarity of bartonellae in individual Costa Rican bats and their bat flies using molecular and sequencing methods targeting the citrate synthase gene (gltA). Bartonellae were more prevalent in bat flies than in bats, and genetic variants were sometimes, but not always, shared between bats and their bat flies. The detected bartonellae genetic variants were diverse, and some were similar to species known to cause disease in humans and other mammals. The high prevalence and sharing of bartonellae in bat flies and bats support a role for bat flies as a potential vector for Bartonella, while the genetic diversity and similarity to known species suggest that bartonellae could spill over into humans and animals sharing the landscape.     

Does calcium constrain reproductive activity in insectivorous bats? Some empirical evidence for Schreibers’ long-fingered bat (Miniopterus schreibersii)

Insects are a poor source of dietary calcium and since they are seasonally abundant, it has been suggested that calcium availability may play a significant role in controlling the timing of reproduction in insectivorous bats. To assess the possible role of dietary calcium, we have measured bone calcium concentrations in female and male long-fingered bats (Miniopterus schreibersii) through a full reproductive cycle. The results indicate that winter was not a period of calcium stress and, therefore, that seasonal changes in insect abundance and dietary calcium availability are not a satisfactory explanation for the occurrence of delayed implantation in the long-fingered bat. Bone calcium concentrations of females did not differ significantly throughout pregnancy, indicating that the insects available in winter and early summer were sufficient to meet the calcium demands of pregnancy. Lactating females had the lowest bone calcium concentrations of all specimens, supporting the suggestion that lactation is indeed a period of severe calcium stress in aerial insectivores. We conclude that parturition is probably timed so that lactation coincides with the period of maximal insect abundance and corresponding dietary calcium availability.     

Novel coronaviruses,astroviruses, adenoviruses and circoviruses in insectivorous bats from northern China

Bats are considered as the reservoirs of several emerging infectious disease, and novel viruses are continually found in bats all around the world. Studies conducted in southern China found that bats carried a variety of viruses. However, few studies have been conducted on bats in northern China, which harbours a diversity of endemic insectivorous bats. It is important to understand the prevalence and diversity of viruses circulating in bats in northern China. In this study, a total of 145 insectivorous bats representing six species were collected from northern China and screened with degenerate primers for viruses belonging to six families, including coronaviruses, astroviruses, hantaviruses, paramyxoviruses, adenoviruses and circoviruses. Our study found that four of the viruses screened for were positive and the overall detection rates for astroviruses, coronaviruses, adenoviruses and circoviruses in bats were 21.4%, 15.9%, 20% and 37.2%, respectively. In addition, we found that bats in northern China harboured a diversity of novel viruses. Common Serotine (Eptesicus serotinu), Fringed long‐footed Myotis (Myotis fimriatus) and Peking Myotis (Myotis pequinius) were investigated in China for the first time. Our study provided new information on the ecology and phylogeny of bat‐borne viruses.     

Neotropical Bats from Costa Rica harbour Diverse Coronaviruses

Bats are hosts of diverse coronaviruses (CoVs) known to potentially cross the host–species barrier. For analysing coronavirus diversity in a bat species‐rich country, a total of 421 anal swabs/faecal samples from Costa Rican bats were screened for CoV RNA‐dependent RNA polymerase (RdRp) gene sequences by a pancoronavirus PCR. Six families, 24 genera and 41 species of bats were analysed. The detection rate for CoV was 1%. Individuals (n = 4) from four different species of frugivorous (Artibeus jamaicensis, Carollia perspicillata and Carollia castanea) and nectivorous (Glossophaga soricina) bats were positive for coronavirus‐derived nucleic acids. Analysis of 440 nt. RdRp sequences allocated all Costa Rican bat CoVs to the α‐CoV group. Several CoVs sequences clustered near previously described CoVs from the same species of bat, but were phylogenetically distant from the human CoV sequences identified to date, suggesting no recent spillover events. The Glossophaga soricina CoV sequence is sufficiently dissimilar (26% homology to the closest known bat CoVs) to represent a unique coronavirus not clustering near other CoVs found in the same bat species so far, implying an even higher CoV diversity than previously suspected.     

Detection of the Severe Acute Respiratory Syndrome‐Related Coronavirus and Alphacoronavirus in the Bat Population of Taiwan

Bats have been demonstrated to be natural reservoirs of severe acute respiratory syndrome coronavirus (SARS CoV) and Middle East respiratory syndrome (MERS) CoV. Faecal samples from 248 individuals of 20 bat species were tested for partial RNA‐dependent RNA polymerase gene of CoV and 57 faecal samples from eight bat species were tested positive. The highest detection rate of 44% for Scotophilus kuhlii, followed by 30% for Rhinolophus monoceros. Significantly higher detection rates of coronaviral RNA were found in female bats and Scotophilus kuhlii roosting in palm trees. Phylogenetic analysis classified the positive samples into SARS‐related (SARSr) CoV, Scotophilus bat CoV 512 close to those from China and Philippines, and Miniopterus bat CoV 1A‐related lineages. Coronaviral RNA was also detected in bat guano from Scotophilus kuhlii and Myotis formosus flavus on the ground and had potential risk for human exposure. Diverse bat CoV with zoonotic potential could be introduced by migratory bats and maintained in the endemic bat population in Taiwan.     

Novel Borrelia genotypes in bats from the Macaregua Cave,Colombia

Bats have been implicated as reservoirs of relapsing fever group spirochaetes since the beginning of the last century. Recently, bat‐associated spirochaetes have been reported as human pathogens. In 1968, a spirochaete was detected in blood of the bat Natalus tumidirostris captured inside the Macaregua cave, Colombia. Data on this microorganism were never published again. The aim of this study was to evaluate the presence of Borrelia DNA in blood from bats of Macaregua cave. We performed molecular analyses using a genus‐specific real‐time PCR targeting the 16S rRNA to detect DNA of Borrelia in blood samples from 46 bats captured in the Macaregua cave. Positive samples were submitted to a battery of PCRs aiming to amply Borrelia 16S rRNA, flaB, glpQ, p66, ospC, clpA, clpX, nifS, pepX, pyrG, recG, rplB and uvrA genes. Seventeen samples were positive for Borrelia after real‐time PCR. With the exception of flaB gene, attempts to amplify further loci were unsuccessful. Nucleotide and amino acid divergences of four flaB haplotypes characterized from blood of Carollia perspicillata showed Borrelia burgdorferi sensu lato (Bbsl) as the most closely related group. A phylogenetic tree including 74 sequences of the genus confirmed this trend, since Borrelia genotypes detected in bats from Macaregua formed a monophyletic group basally positioned to Bbsl. Our results suggest that Borrelia genotypes characterized from bats roosting in the Macaregua cave might constitute a new taxon within the genus. This is the first molecular characterization of a Borrelia sp. in Colombia.     

Expression levels of taste‐related genes in palate and tongue tip,and involvement of transient receptor potential subfamily M member 5 (TRPM5) in taste sense in chickens

The elucidation of the mechanisms underlying the taste sense of chickens will contribute to improvements in poultry feeding, because the molecular mechanism of chickens’ taste sense defines the feeding behavior of chickens. Here we focused on the gene expressions in two different oral tissues of chickens – the palate, which contains many taste buds, and the tongue tip, which contains few taste buds. Using the quantitative real‐time polymerase chain reaction method, we found that the molecular markers for taste buds of chickens, that is α‐gustducin and vimentin, were expressed significantly highly in the palate compared to the tongue tip. Our analyses also revealed that transient receptor potential subfamily M member 5 (TRPM5), a cation channel involved in taste transduction in mammals, was also highly expressed in the palate compared to the tongue tip. Our findings demonstrated that the expression patterns of these genes were significantly correlated. We showed that the aversion to bitter solution was alleviated by a TRPM5 inhibitor in behavior of chickens. Taken together, our findings enabled us to develop a simple method for screening taste‐related genes in chickens. The use of this method demonstrated that TRPM5 was involved in chickens’ taste transduction, and that a TRPM5 inhibitor can alleviate chickens’ bitter taste perception of feed ingredients.     

苦味受体的生物学特征、信号转导机制及苦味剂和苦味抑制剂对苦味受体的影响

苦味受体(bitter taste receptors,TAS2Rs)是一种G-蛋白偶联受体(GPCR),由30个基因组成的基因家族编码。苦味可使动物远离有毒有害物质,当动物尝到苦味物质时,会刺激舌头的味蕾中味觉受体细胞表达TAS2Rs,进而引发下游一系列信号转导反应,最终通过鼓索神经和舌咽神经将信息整合传到大脑,使动物产生厌恶的感觉,从而选择拒绝摄入这些苦味物质。本文就TAS2Rs的生物学特征、信号转导机制及苦味剂和苦味抑制剂对苦味受体的影响进行简要综述。     

Zoonotic pathogens isolated from wild animals and environmental samples at two California wildlife hospitals

During 2010, 48 states and Puerto Rico reported 6,154 rabid animals and 2 human rabies cases to the CDC, representing an 8% decrease from the 6,690 rabid animals and 4 human cases reported in 2009. Hawaii and Mississippi did not report any laboratory-confirmed rabid animals during 2010. Approximately 92% of reported rabid animals were wildlife. Relative contributions by the major animal groups were as follows: 2,246 raccoons (36.5%), 1,448 skunks (23.5%), 1,430 bats (23.2%), 429 foxes (6.9%), 303 cats (4.9%), 71 cattle (1.1 %), and 69 dogs (1.1 %). Compared with 2009, number of reported rabid animals decreased across all animal types with the exception of a 1 % increase in the number of reported rabid cats. Two cases of rabies involving humans were reported from Louisiana and Wisconsin in 2010. Louisiana reported an imported human rabies case involving a 19-year-old male migrant farm worker who had a history of a vampire bat (Desmodus rotundus) bite received while in Mexico. This represents the first human rabies case reported in the United States confirmed to have been caused by a vampire bat rabies virus variant. Wisconsin reported a human rabies case involving a 70-year-old male that was confirmed to have been caused by a rabies virus variant associated with tri-colored bats (Perimyotis subflavus).     

Radiographic anatomy of the heart of fruit bats

As the only mammal that can fly, bats have organ systems with a unique morphophysiology. One of the highlights is the heart and blood circulation system, which must be able to meet the needs of blood and oxygen supply when flying. This study examined the radiography of the normal condition of the heart organ in 3 species of fruit bats, namely Cynopterus titthaecheilus, Cynopterus brachyotis and Rousettus leschenaultii using radiological silhouette analysis and clock analogy. The results showed that the heart positions of the three bat species tend to be tilted to the left with the apex moving away from the midsagittal plane. Analysis of intercostal space (ICS) value and vertebral heart score (VHS), and evaluation of radiographic features showed R. leschenaultii has a relatively larger heart size than the other two species. All three bat species have a higher VHS than mammals in general. Radiographic images obtained, and interpretation results show the position, size and normal heart parts of the three bat species. They will be useful in diagnostic efforts related to heart problems in these three species.     

Knowledge,perceptions and attitude of a community living around a colony of straw‐coloured fruit bats (Eidolon helvum) in Ghana after Ebola virus disease outbreak in West Africa

A large population of straw‐coloured fruit bats (Eidolon helvum) colonizes a prime area in the city of Accra where several public amenities are located. Although the colony is positive to several zoonotic viruses including the Ebola virus, there is limited information on the social dimensions of the existence of the bats. As a step towards effective response to health risk and conservation of the bats, this study assessed the knowledge and attitude of the community living around the bats and determined their level of environmental and public health consciousness. The community generally lacks interest in bat bushmeat consumption but had low knowledge and disease risk perception of the bats. Despite major campaigns during the recent Ebola outbreak in West Africa, elements of risky behaviour including disbelief and disregard for some preventive measures and lack of interest in post‐bat exposure prophylaxis were recorded among a limited proportion of the community. There was the need to focus public health education on the community and possibly others that may have E. helvum colonies in West Africa.     

Genetic analysis of phosphoprotein and matrix protein of rabies viruses isolated in Brazil

To investigate the genetic characteristics of phosphoprotein (P) and matrix protein (M) genes of variable rabies virus (RV) prevalent in Brazil, the authors genetically characterized the P and M genes from 30 Brazilian RV field isolates. Phylogenetic analysis based on the P and M genes revealed the presence of six RV variants that consisted primarily of three insectivorous bats, the vampire bat, dog and fox in Brazil. Specific amino acid substitutions corresponding to these phylogenetic lineages were observed, with Asp(42) and Glu(62) in the P protein found to be characteristic of Brazilian chiroptera- and carnivora-related RVs, respectively. Amino acid sequence motifs predicted to associate with a viral function in the P and M proteins were conserved among Brazilian RV variants.     

Extended‐spectrum beta‐lactamase‐producing Escherichia coli in common vampire bats Desmodus rotundus and livestock in Peru

Antibiotic resistance mediated by bacterial production of extended‐spectrum beta‐lactamase (ESBL) is a global threat to public health. ESBL resistance is most commonly hospital‐acquired; however, infections acquired outside of hospital settings have raised concerns over the role of livestock and wildlife in the zoonotic spread of ESBL‐producing bacteria. Only limited data are available on the circulation of ESBL‐producing bacteria in animals. Here, we report ESBL‐producing Escherichia coli in wild common vampire bats Desmodus rotundus and livestock near Lima, Peru. Molecular analyses revealed that most of this resistance resulted from the expression of bla_CTX‐M‐15 genes carried by plasmids, which are disseminating worldwide in hospital settings and have also been observed in healthy children of Peru. Multilocus sequence typing showed a diverse pool of E. coli strains carrying this resistance that were not always host species‐specific, suggesting sharing of strains between species or infection from a common source. This study shows widespread ESBL resistance in wild and domestic animals, supporting animal communities as a potential source of resistance. Future work is needed to elucidate the role of bats in the dissemination of antibiotic‐resistant strains of public health importance and to understand the origin of the observed resistance.     

Faeces as a novel material to estimate lyssavirus prevalence in bat populations

Rabies is caused by infection with a lyssavirus. Bat rabies is of concern for both public health and bat conservation. The current method for lyssavirus prevalence studies in bat populations is by oral swabbing, which is invasive for the bats, dangerous for handlers, time‐consuming and expensive. In many situations, such sampling is not feasible, and hence, our understanding of epidemiology of bat rabies is limited. Faeces are usually easy to collect from bat colonies without disturbing the bats and thus could be a practical and feasible material for lyssavirus prevalence studies. To further explore this idea, we performed virological analysis on faecal pellets and oral swabs of seven serotine bats (Eptesicus serotinus) that were positive for European bat 1 lyssavirus in the brain. We also performed immunohistochemical and virological analyses on digestive tract samples of these bats to determine potential sources of lyssavirus in the faeces. We found that lyssavirus detection by RT‐qPCR was nearly as sensitive in faecal pellets (6/7 bats positive, 86%) as in oral swabs (7/7 bats positive, 100%). The likely source of lyssavirus in the faeces was virus excreted into the oral cavity from the salivary glands (5/6 bats positive by immunohistochemistry and RT‐qPCR) or tongue (3/4 bats positive by immunohistochemistry) and swallowed with saliva. Virus could not be isolated from any of the seven faecal pellets, suggesting the lyssavirus detected in faeces is not infectious. Lyssavirus detection in the majority of faecal pellets of infected bats shows that this novel material should be further explored for lyssavirus prevalence studies in bats.     

Determination and molecular analysis of the complete genome sequence of two wild-type rabies viruses isolated from a haematophagous bat and a frugivorous bat in Brazil

The complete genome sequences of two Brazilian wild-type rabies viruses (RABV), a BR-DR1 isolate from a haematophagous bat (Desmodus rotundus) and a BR-AL1 isolate from a frugivorous bat (Artibeus lituratus), were determined. The genomes of the BR-DR1 and BR-AL1 had 11,923 and 11,922 nt, respectively, and both encoded the five standard genes of rhabdoviruses. The complete nucleotide sequence identity between the BR-DR1 and BR-AL1 isolates was 97%. The BR-DR1 and BR-AL1 isolates had some conserved functional sites revealed by the fixed isolates, whereas both isolates had unique amino acid substitutions in the antigenic region IV of the nucleocapsid gene. Therefore, it is speculated that both isolates were nearly identical in virologic character. According to our phylogenetic analysis based on the complete genomes, both isolates belonged to genotype 1, and to the previously defined "vampire bat-related RABV lineage" which consisted of mainly D. rotundus- and A. lituratus-isolates; however, a branch pattern with high bootstrap values suggested that BR-DR1 was more closely related to the 9001FRA isolate, which was collected from a dog bitten by a bat in French Guiana, than to BR-AL1. This result suggests that the vampire bat-related RABV lineage includes Brazilian vampire bat and Brazilian frugivorous bat RABV and is further divided into Brazilian vampire bat and Brazilian frugivorous bat RABV sub-lineages. The phylogenetic analysis based on the complete genomes was valuable in discriminating among very closely related isolates.