Bat rabies in urban centers in Chile

One hundred and five rabies isolates obtained from domestic animals and insectivorous bats in Chile between 1977 and 1998 were molecularly characterized by limited sequence analysis of their nucleoprotein genes. These isolates were compared with viruses isolated from known domestic and wildlife rabies reservoirs in the Americas to identify potential reservoirs of rabies in Chile. The phylogenetic analyses showed that none of the Chilean isolates segregated with viruses from the terrestrial reservoirs. No non-rabies lyssaviruses were found in this study. The Chilean samples were not related to viruses of the sylvatic cycle maintained by the common vampire bat (Desmodus rotundus) in Latin America. Five genetic variants were identified from insectivorous bats in Chile. The Brazilian free-tailed bat (Tadarida brasiliensis) was identified as the reservoir for the rabies genetic variant most frequently isolated in the country between 1977 and 1998. The close association of a group of viruses obtained from a domestic dog (Canis familiaris), Brazilian free-tailed bats, and a red bat (Lasiurus borealis) with viruses maintained by Lasiurus spp. in North America implicated species of this genus as the possible reservoirs of this particular genetic variant in Chile. Reservoirs for the other three variants remain unknown.     

Bat rabies in South Carolina, 1970-90.

This retrospective study examines the geographic and temporal distribution of bat species submitted for rabies testing in South Carolina (USA) from 1970 to 1990. Histories of human or animal exposures to rabid and nonrabid bats submitted during this time period were compared. Two hundred and thirty-one bats were found to be rabid from the 2,657 bats submitted over this 20 yr period. The two species most frequently submitted for testing were Lasiurus borealis with 785 specimens (30% of the total) and Nycticeius humeralis with 607 specimens (22% of the total). Lasiurus borealis also had the highest prevalence of rabies (18%) while N. humeralis had the lowest prevalence (3%). Fifty-one percent (1,259) of the bats received for testing were submitted from June through August. The majority (54%) of rabid bats were received from August through October.     

The development of rabies in Tunisia from 1982 to 1986

The authors describe the epidemiology of rabies disease in Tunisia since 1982, the problem of reservoirs and vectors, the production of vaccine, the diagnosis and the treatment of the disease. They note that this disease is decreasing in the animals that have bitten, nevertheless the canine rabies remains an important problem of public health in the country.     

Bat rabies surveillance in France: first report of unusual mortality among serotine bats

Background

Rabies is a fatal viral encephalitic disease that is caused by lyssaviruses which can affect all mammals, including human and bats. In Europe, bat rabies cases are attributed to five different lyssavirus species, the majority of rabid bats being attributed to European bat 1 lyssavirus (EBLV-1), circulating mainly in serotine bats (Eptesicus serotinus). In France, rabies in bats is under surveillance since 1989, with 77 positive cases reported between 1989 and 2016.

Case presentation

In the frame of the bat rabies surveillance, an unusual mortality of serotine bats was reported in 2009 in a village in North-East France. Six juvenile bats from an E. serotinus maternity colony counting ~200 individuals were found to be infected with EBLV-1. The active surveillance of the colony by capture sessions of bats from July to September 2009 showed a high detection rate of neutralising EBLV-1 antibodies (≈ 50%) in the colony. Moreover, one out of 111 animals tested was found to shed viable virus in saliva, while lyssavirus RNA was detected by RT-PCR for five individuals.

Conclusion

This study demonstrated that the lyssavirus infection in the serotine maternity colony was followed by a high rate of bat rabies immunity after circulation of the virus in the colony. The ratio of seropositive bats is probably indicative of an efficient virus transmission coupled to a rapid circulation of EBLV-1 in the colony.

     

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 (302_T,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.     

BGD: A Database of Bat Genomes

Bats account for ~20% of mammalian species, and are the only mammals with true powered flight. For the sake of their specialized phenotypic traits, many researches have been devoted to examine the evolution of bats. Until now, some whole genome sequences of bats have been assembled and annotated, however, a uniform resource for the annotated bat genomes is still unavailable. To make the extensive data associated with the bat genomes accessible to the general biological communities, we established a Bat Genome Database (BGD). BGD is an open-access, web-available portal that integrates available data of bat genomes and genes. It hosts data from six bat species, including two megabats and four microbats. Users can query the gene annotations using efficient searching engine, and it offers browsable tracks of bat genomes. Furthermore, an easy-to-use phylogenetic analysis tool was also provided to facilitate online phylogeny study of genes. To the best of our knowledge, BGD is the first database of bat genomes. It will extend our understanding of the bat evolution and be advantageous to the bat sequences analysis. BGD is freely available at: http://donglab.ecnu.edu.cn/databases/BatGenome/.     

Matching Gas Exchange in the Bat from Flight to Torpor

SYNOPSIS. Many microchiropteran bats can reduce their metabolicrate three orders of magnitude during heterothermic torpor.This extraordinary range provides a unique insight into theadaptability of mammalian ventilatory control and function.To enable powered flight, bats have developed the highest capacitygas exchange system among mammals. However, starving duringwinter may account for the greatest mortality among bats thathibernate, thus imposing a strong selective pressure to decreasemetabolic cost during torpor. This high capacity gas exchangesystem must therefore operate efficiently at very reduced rates,despite conflicting mechanical constraints imposed by an enormousfunctional overhead. The bat surmounts this dilemma by adjustingits control strategy to breathe intermittently during torpor.This allows instantaneous breathing rates and tidal volumesnear predicted optimal levels. In addition, a passive oxygeninflux coupled with a high acidotic tolerance facilitates longerintervals between the breathing bouts. The acidotic tolerancesupports the endurance of these apneas because the passive effluxof carbon dioxide does not match the rate of oxygen influx.The acidotic tolerance further helps by allowing carbon dioxideto enrich the alveolar gas during apnea to levels above thatof a nonacidotic, continuous pattern of breathing. Thus, thebat's carbon dioxide load can be cleared in fewer breaths whenbreathing resumes. By efficiently controlling a high capacitygas exchange system to meet the minuscule demands during torpor,the bat demonstrates how physiological control strategies canadapt to overcome limitations imposed by conflicting selectionpressures.     

Failure to cultivate rabies virus in vitro

Summary Report of the unsuccessful cultivation of rabies fixed virus in a cell-free medium consisting of steamed sheep-brain extract, glycine, peptone and a number of accessory factors (tryptophan, aneurine, nicotinic acid amide, pyridoxine hydrochloride, sodium pantothenate and lactoflavin). After 24 and 48 hour's incubation at 37° C, under aerobic conditions, the virus had completely lost its virulence, and did not induce immunity to reinoculation with active virus.     

Erratum to: Bat origin of a new human coronavirus: there and back again

正We miscalculated identities of several genes, and the corrected Table 1 should be as follows:a) This table demonstrates identities of 2019-nCoV WIV04 (GenBank Accession No. MN996528.1) compared with bat SARSr-CoV RaTG13 (GenBank Accession No. MN996532.1) and SARS-CoV BJ01 (GenBank Accession No. AY278488.2). Identities were calculated by using nucleotide sequences and     

Bat echolocation calls: adaptation and convergent evolution

Bat echolocation calls provide remarkable examples of 'good design' through evolution by natural selection. Theory developed from acoustics and sonar engineering permits a strong predictive basis for understanding echolocation performance. Call features, such as frequency, bandwidth, duration and pulse interval are all related to ecological niche. Recent technological breakthroughs have aided our understanding of adaptive aspects of call design in free-living bats. Stereo videogrammetry, laser scanning of habitat features and acoustic flight path tracking permit reconstruction of the flight paths of echolocating bats relative to obstacles and prey in nature. These methods show that echolocation calls are among the most intense airborne vocalizations produced by animals. Acoustic tracking has clarified how and why bats vary call structure in relation to flight speed. Bats using broadband echolocation calls adjust call design in a range-dependent manner so that nearby obstacles are localized accurately. Recent phylogenetic analyses based on gene sequences show that particular types of echolocation signals have evolved independently in several lineages of bats. Call design is often influenced more by perceptual challenges imposed by the environment than by phylogeny, and provides excellent examples of convergent evolution. Now that whole genome sequences of bats are imminent, understanding the functional genomics of echolocation will become a major challenge.     

Human trichinellosis in Hungary from 1965 to 2009

Human trichinellosis was first documented in Hungary in 1891 and then there were an increased number of reports up to 1964 when the most severe outbreak occurred. After that, no information was available on the international literature on human trichinellosis which occurred from 1965 up to the present years. The aim of this study was to collect all the data available in Hungarian official data-sources on human trichinellosis which occurred from 1965 up to 2009 in Hungary. Furthermore, a comparative analysis was performed on the different serological tests used along the 45 years of investigation. In the period in question, 573 infections were documented in Hungary. Of them, 57 occurred in the years 1965-69, 130 in 1970-79, 302 in 1980-89, 27 in 1990-99, and 57 in 200009. The most common sources of infection were pork from backyard pigs and hunted wild boars. Sporadic cases and small family outbreaks marked the last ten years. The comparison of serological tests shows that the ELISA is a good test for the first screening, but ELISA-positive serum samples should be confirmed by western blot except for clinically clear-cut cases.     

Rates of Viral Evolution Are Linked to Host Geography in Bat Rabies

Rates of evolution span orders of magnitude among RNA viruses with important implications for viral transmission and emergence. Although the tempo of viral evolution is often ascribed to viral features such as mutation rates and transmission mode, these factors alone cannot explain variation among closely related viruses, where host biology might operate more strongly on viral evolution. Here, we analyzed sequence data from hundreds of rabies viruses collected from bats throughout the Americas to describe dramatic variation in the speed of rabies virus evolution when circulating in ecologically distinct reservoir species. Integration of ecological and genetic data through a comparative Bayesian analysis revealed that viral evolutionary rates were labile following historical jumps between bat species and nearly four times faster in tropical and subtropical bats compared to temperate species. The association between geography and viral evolution could not be explained by host metabolism, phylogeny or variable selection pressures, and instead appeared to be a consequence of reduced seasonality in bat activity and virus transmission associated with climate. Our results demonstrate a key role for host ecology in shaping the tempo of evolution in multi-host viruses and highlight the power of comparative phylogenetic methods to identify the host and environmental features that influence transmission dynamics.