RESUMEN
BACKGROUND: Vampire bat-transmitted cattle rabies cases are typically encountered in areas where the disease is endemic. However, over the period of a month in 2009, an outbreak of cattle rabies occurred and then ended spontaneously in a small area of the Rio Grande do Sul State in southern Brazil. To investigate the epidemiological characteristics of this rabies outbreak in Rio Grande do Sul, 26 nucleotide sequences of rabies virus (RABV) genomes that were collected in this area were analyzed phylogenetically. RESULTS: Nucleotide sequence identities of the nucleoprotein gene and G-L intergenic region of the 26 RABVs were greater than 99.6 %. Phylogenetic analysis showed that all RABVs clustered with the vampire bat-related cattle RABV strains and that the RABVs were mainly distributed in southern Brazil. CONCLUSIONS: The findings of the present study suggested that a small population of rabid vampire bats carrying a single RABV strain produced a spatiotemporally restricted outbreak of cattle rabies in southern Brazil.
Asunto(s)
Enfermedades de los Bovinos/virología , Brotes de Enfermedades/estadística & datos numéricos , Animales , Secuencia de Bases , Brasil/epidemiología , Bovinos , Geografía , Epidemiología Molecular , FilogeniaRESUMEN
A rabies virus isolate (BRmk1358 strain) was discovered from a rabid tufted capuchin monkey in Brazil. The present study determined the nucleotide sequence of the BRmk1358 strain and compared with the rabies viruses isolated from marmosets and other animals in the Americas. Phylogenetic analyses showed that the BRmk1358 strain formed a lineage distant from that of marmoset rabies virus within the Chiroptera-related rabies virus cluster. This result suggests that the source of rabies infection in the tufted capuchin monkey may have been bat, and that they have a risk to act as rabies reservoir in Brazil.
Asunto(s)
Cebus/virología , Enfermedades de los Primates/virología , Virus de la Rabia/clasificación , Virus de la Rabia/aislamiento & purificación , Rabia/veterinaria , Animales , Brasil , Análisis por Conglomerados , Datos de Secuencia Molecular , Filogenia , ARN Viral/genética , Rabia/virología , Virus de la Rabia/genética , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: Limited or no epidemiological information has been reported for rabies viruses (RABVs) isolated from livestock in the northeastern Brazilian states of Paraíba (PB) and Pernambuco (PE). The aim of this study was to clarify the molecular epidemiology of RABVs circulating in livestock, especially cattle, in these areas between 2003 and 2009. FINDINGS: Phylogenetic analysis based on 890 nt of the nucleoprotein (N) gene revealed that the 52 livestock-derived RABV isolates characterized here belonged to a single lineage. These isolates clustered with a vampire bat-related RABV lineage previously identified in other states in Brazil; within PB and PE, this lineage was divided between the previously characterized main lineage and a novel sub-lineage. CONCLUSIONS: The occurrences of livestock rabies in PB and PE originated from vampire bat RABVs, and the causative RABV lineage has been circulating in this area of northeastern Brazil for at least 7 years. This distribution pattern may correlate to that of a vampire bat population isolated by geographic barriers.
RESUMEN
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.
Asunto(s)
Quirópteros/virología , Virus de la Rabia/genética , Virus de la Rabia/aislamiento & purificación , Rabia/veterinaria , Rabia/virología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Brasil , Genoma Viral/genética , Datos de Secuencia Molecular , Filogenia , ARN Viral/química , ARN Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de SecuenciaRESUMEN
Although dogs are considered to be the principal transmitter of rabies in Brazil, dog rabies had never been recorded in South America before European colonization. In order to investigate the evolutionary history of dog rabies virus (RABV) in Brazil, we performed a phylogenetic analysis of carnivore RABV isolates from around the world and estimated the divergence times for dog RABV in Brazil. Our estimate for the time of introduction of dog RABV into Brazil was the late-19th to early-20th century, which was later than the colonization period but corresponded to a period of increased immigration from Europe to Brazil. In addition, dog RABVs appeared to have spread to indigenous animals in Brazil during the latter half of the 20th century, when the development and urbanization of Brazil occurred. These results suggest that the movement of rabid dogs, along with human activities since the 19th century, promoted the introduction and expansion of dog RABV in Brazil.
Asunto(s)
Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/virología , Evolución Molecular , Polimorfismo Genético , Virus de la Rabia/clasificación , Virus de la Rabia/genética , Rabia/veterinaria , Animales , Brasil/epidemiología , Análisis por Conglomerados , Enfermedades de los Perros/historia , Perros , Genotipo , Historia del Siglo XIX , Historia del Siglo XX , Historia del Siglo XXI , Datos de Secuencia Molecular , Filogenia , ARN Viral/genética , Rabia/epidemiología , Rabia/historia , Rabia/virología , Virus de la Rabia/aislamiento & purificación , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: Vampire bat related rabies harms both livestock industry and public health sector in central Brazil. The geographical distributions of vampire bat-transmitted rabies virus variants are delimited by mountain chains. These findings were elucidated by analyzing a high conserved nucleoprotein gene. This study aims to elucidate the detailed epidemiological characters of vampire bat-transmitted rabies virus by phylogenetic methods based on 619-nt sequence including unconserved G-L intergenic region. FINDINGS: The vampire bat-transmitted rabies virus isolates divided into 8 phylogenetic lineages in the previous nucleoprotein gene analysis were divided into 10 phylogenetic lineages with significant bootstrap values. The distributions of most variants were reconfirmed to be delimited by mountain chains. Furthermore, variants in undulating areas have narrow distributions and are apparently separated by mountain ridges. CONCLUSIONS: This study demonstrates that the 619-nt sequence including G-L intergenic region is more useful for a state-level phylogenetic analysis of rabies virus than the partial nucleoprotein gene, and simultaneously that the distribution of vampire bat-transmitted RABV variants tends to be separated not only by mountain chains but also by mountain ridges, thus suggesting that the diversity of vampire bat-transmitted RABV variants was delimited by geographical undulations.
RESUMEN
This study was aimed to evaluate and compare the pathogenicity of rabies virus isolated from bats and dogs, and to verify the efficacy of a commercial rabies vaccine against these isolates. For evaluation of pathogenicity, mice were inoculated by the intramuscular route (IM) with 500MICLD50/0.03 mL of the viruses. The cross-protection test was performed by vaccinating groups of mice by the subcutaneous route and challenged through the intracerebral (IC) route. Isolates were fully pathogenic when inoculated by the IC route. When inoculated intramuscularly, the pathogenicity observed showed different death rates: 60.0% for the Desmodus rotundus isolate; 50.0% for dog and Nyctinomops laticaudatus isolates; 40.0% for Artibeus lituratus isolate; 9.5% Molossus molossus isolate; and 5.2% for the Eptesicus furinalis isolate. Mice receiving two doses of the vaccine and challenged by the IC route with the isolates were fully protected. Mice receiving only one dose of vaccine were partially protected against the dog isolate. The isolates from bats were pathogenic by the IC route in mice. However, when inoculated through the intramuscular route, the same isolates were found with different degrees of pathogenicity. The results of this work suggest that a commercial vaccine protects mice from infection with bat rabies virus isolates, in addition to a canine rabies virus isolate.
Asunto(s)
Vacunas Antirrábicas/inmunología , Virus de la Rabia/patogenicidad , Rabia/prevención & control , Animales , Quirópteros , Perros , Femenino , Dosificación Letal Mediana , Ratones , Rabia/inmunología , Vacunas Antirrábicas/administración & dosificación , Virus de la Rabia/clasificación , Virus de la Rabia/inmunologíaRESUMEN
This study was aimed to evaluate and compare the pathogenicity of rabies virus isolated from bats and dogs, and to verify the efficacy of a commercial rabies vaccine against these isolates. For evaluation of pathogenicity, mice were inoculated by the intramuscular route (IM) with 500MICLD50/0.03mL of the viruses. The cross-protection test was performed by vaccinating groups of mice by the subcutaneous route and challenged through the intracerebral (IC) route. Isolates were fully pathogenic when inoculated by the IC route. When inoculated intramuscularly, the pathogenicity observed showed different death rates: 60.0 percent for the Desmodus rotundus isolate; 50.0 percent for dog and Nyctinomops laticaudatus isolates; 40.0 percent for Artibeus lituratus isolate; 9.5 percent Molossus molossus isolate; and 5.2 percent for the Eptesicus furinalis isolate. Mice receiving two doses of the vaccine and challenged by the IC route with the isolates were fully protected. Mice receiving only one dose of vaccine were partially protected against the dog isolate. The isolates from bats were pathogenic by the IC route in mice. However, when inoculated through the intramuscular route, the same isolates were found with different degrees of pathogenicity. The results of this work suggest that a commercial vaccine protects mice from infection with bat rabies virus isolates, in addition to a canine rabies virus isolate.
O estudo avaliou e comparou as propriedades patogênicas de cinco isolados do vírus da raiva de morcegos e um isolado do vírus da raiva de cão e analisou a eficácia de vacina comercial contra estes isolados, em camundongos. Para o estudo de patogenicidade camundongos foram inoculados pela via IM com 0,1 mL contendo 500MICLD50/0,03mL das amostras de vírus. Quando inoculados pela via IC, os isolados do vírus da raiva provocaram a morte de 100 por cento dos camundongos. No entanto, 500MICLD50/0,03mL das mesmas amostras, inoculadas pela via IM, ocasionaram mortalidade de: 60,0 por cento quando a amostra era de Desmodus rotundus; 50,0 por cento de cão e de Nyctinomops laticaudatus; 40,0 por cento de Artibeus lituratus; 9,5 por cento de Molossus molossus; e 5,2 por cento de Eptesicus furinalis. Camundongos que receberam duas doses de vacina foram protegidos quando desafiados pela via IC, com todas as amostras testadas. Quando os camundongos receberam uma dose da mesma vacina, houve proteção parcial daqueles desafiados com a amostra de cão. Todos os isolados do vírus da raiva testados foram patogênicos para camundongos, inoculados pela IC. No entanto, pela via IM, os mesmos isolados mostraram diferentes graus de patogenicidade. Concluiu-se também que a vacina comercial contra raiva protegeu os camundongos desafiados com amostras de vírus isolados de morcegos e de cão.
Asunto(s)
Animales , Perros , Femenino , Ratones , Vacunas Antirrábicas/inmunología , Virus de la Rabia/patogenicidad , Rabia/prevención & control , Quirópteros , Vacunas Antirrábicas/administración & dosificación , Virus de la Rabia/clasificación , Virus de la Rabia/inmunología , Rabia/inmunologíaRESUMEN
At present, the sporadic occurrence of human rabies in Brazil can be attributed primarily to dog- and vampire bat-related rabies viruses. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) was employed as a simultaneous detection method for both rabies field variants within 60 min. Vampire bat-related rabies viruses could be distinguished from dog variants by digesting amplicons of the RT-LAMP reaction using the restriction enzyme AlwI. Amplification and digestion could both be completed within 120 min after RNA extraction. In addition, the RT-LAMP assay also detected rabies virus in isolates from Brazilian frugivorous bats and Ugandan dog, bovine and goat samples. In contrast, there were false negative results from several Brazilian insectivorous bats and all of Chinese dog, pig, and bovine samples using the RT-LAMP assay. This study showed that the RT-LAMP assay is effective for the rapid detection of rabies virus isolates from the primary reservoir in Brazil. Further improvements are necessary so that the RT-LAMP assay can be employed for the universal detection of genetic variants of rabies virus in the field.
Asunto(s)
Técnicas de Amplificación de Ácido Nucleico/métodos , Virus de la Rabia/clasificación , Virus de la Rabia/aislamiento & purificación , Rabia/veterinaria , Transcripción Reversa , Virología/métodos , Animales , Brasil , Bovinos , Quirópteros , Cartilla de ADN/genética , Perros , Cabras , Humanos , Datos de Secuencia Molecular , ARN Viral/genética , Rabia/diagnóstico , Virus de la Rabia/genética , Sensibilidad y Especificidad , Análisis de Secuencia de ADN , Porcinos , Factores de TiempoRESUMEN
The low rates of nonsynonymous evolution observed in natural rabies virus (RABV) isolates are suggested to have arisen in association with the structural and functional constraints operating on the virus protein and the infection strategies employed by RABV within infected hosts to avoid strong selection by the immune response. In order to investigate the relationship between the genetic characteristics of RABV populations within hosts and the virus evolution, the present study examined the genetic heterogeneities of RABV populations within naturally infected dogs and foxes in Brazil, as well as those of bat RABV populations that were passaged once in suckling mice. Sequence analyses of complete RABV glycoprotein (G) genes showed that RABV populations within infected hosts were genetically highly homogeneous whether they were infected naturally or experimentally (nucleotide diversities of 0-0.95x10(-3)). In addition, amino acid mutations were randomly distributed over the entire region of the G protein, and the nonsynonymous/synonymous rate ratios (d(N)/d(S)) for the G protein gene were less than 1. These findings suggest that the low genetic diversities of RABV populations within hosts reflect the stabilizing selection operating on the virus, the infection strategies of the virus, and eventually, the evolutionary patterns of the virus.
Asunto(s)
Mutación , Virus de la Rabia/genética , Rabia/virología , Animales , Antígenos Virales/química , Antígenos Virales/genética , Encéfalo/virología , Brasil , Quirópteros , Bases de Datos de Ácidos Nucleicos , Perros , Zorros , Glicoproteínas/química , Glicoproteínas/genética , Virus de la Rabia/aislamiento & purificación , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/genéticaRESUMEN
BACKGROUND: Vampire bats are important rabies virus vectors, causing critical problems in both the livestock industry and public health sector in Latin America. In order to assess the epidemiological characteristics of vampire bat-transmitted rabies, the authors conducted phylogenetic and geographical analyses using sequence data of a large number of cattle rabies isolates collected from a wide geographical area in Brazil. METHODS: Partial nucleoprotein genes of rabies viruses isolated from 666 cattle and 18 vampire bats between 1987 and 2006 were sequenced and used for phylogenetic analysis. The genetic variants were plotted on topographical maps of Brazil. RESULTS: In this study, 593 samples consisting of 24 genetic variants were analyzed. Regional localization of variants was observed, with the distribution of several variants found to be delimited by mountain ranges which served as geographic boundaries. The geographical distributions of vampire-bat and cattle isolates that were classified as the identical phylogenetic group were found to overlap with high certainty. Most of the samples analyzed in this study were isolated from adjacent areas linked by rivers. CONCLUSION: This study revealed the existence of several dozen regional variants associated with vampire bats in Brazil, with the distribution patterns of these variants found to be affected by mountain ranges and rivers. These results suggest that epidemiological characteristics of vampire bat-related rabies appear to be associated with the topographical and geographical characteristics of areas where cattle are maintained, and the factors affecting vampire bat ecology.
Asunto(s)
Enfermedades de los Bovinos/epidemiología , Quirópteros/virología , Vectores de Enfermedades , Virus de la Rabia/genética , Rabia/veterinaria , Animales , Brasil/epidemiología , Bovinos , Enfermedades de los Bovinos/transmisión , Enfermedades de los Bovinos/virología , Variación Genética , Datos de Secuencia Molecular , Nucleoproteínas/genética , Filogenia , Rabia/epidemiología , Rabia/transmisión , Virus de la Rabia/aislamiento & purificaciónRESUMEN
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.
Asunto(s)
Fosfoproteínas/genética , Virus de la Rabia/genética , Proteínas de la Matriz Viral/genética , Proteínas Estructurales Virales/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Brasil , Variación Genética , Chaperonas Moleculares , Datos de Secuencia Molecular , Filogenia , Virus de la Rabia/aislamiento & purificaciónRESUMEN
The incidence of canine rabies has been widely reported in Brazil, and new rabies virus (RV) variants, genetically similar to canine RV, have recently been isolated from foxes. In order to derive the epidemiological characteristics of Brazilian Carnivora RV, Brazilian RVs isolated from dogs, cats, and foxes were genetically analyzed. Brazilian Carnivora RV isolates were divided into 2 main lineages. The predominant lineage was found in dogs and cats, which included the Argentinean and Bolivian Carnivora RV isolates, and was extensively distributed throughout Brazil and surrounding countries. The other lineage consisted of three sublineages containing Brazilian dog and fox RV isolates, with the dog sublineages located on an internal branch of 2 fox sublineages, suggesting that RV transmission events might have occurred between foxes and dogs in the past. These results suggest that contact between dogs and wildlife has the potential to generate new rabies variants and that it is important to control RV infection cycles in both dogs and wildlife to prevent spread of rabies infection.
Asunto(s)
Enfermedades de los Gatos/virología , Enfermedades de los Perros/virología , Virus de la Rabia/genética , Rabia/veterinaria , Animales , Secuencia de Bases , Brasil/epidemiología , Enfermedades de los Gatos/epidemiología , Gatos , Enfermedades de los Perros/epidemiología , Perros , Zorros , Datos de Secuencia Molecular , Filogenia , ARN Viral/química , ARN Viral/genética , Rabia/epidemiología , Rabia/virología , Virus de la Rabia/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Alineación de Secuencia , Análisis de Secuencia de ProteínaRESUMEN
Seventy-seven rabies virus (RV) isolates originating from Brazilian cattle were genetically characterized. Partial nucleoprotein gene sequences of these isolates were phylogenetically and geographically analyzed. Cattle isolates, which clustered with the vampire bat-related RV group, were further subdivided into nine genetic subgroups. These subgroups were distributed widely in lowland regions, with some subgroups separated from each other by mountain ranges. In addition, separation of the groups in mountainous regions was correlated with altitude. These results indicate that cattle rabies is derived from several regionally-defined variants, which suggests that its geographical distribution is related to that of the vampire bat population.
Asunto(s)
Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/virología , Quirópteros/virología , Virus de la Rabia/crecimiento & desarrollo , Rabia/veterinaria , Animales , Secuencia de Bases , Brasil/epidemiología , Bovinos , Análisis por Conglomerados , Datos de Secuencia Molecular , Proteínas de la Nucleocápside/química , Proteínas de la Nucleocápside/genética , Filogenia , ARN Viral/química , ARN Viral/genética , Rabia/epidemiología , Rabia/virología , Virus de la Rabia/genética , Alineación de SecuenciaRESUMEN
A molecular epidemiological analysis was performed in 19 rabies viruses (RVs) isolated from haematophagous, frugivorous and insectivorous bats, in Sao Paulo, Brazil. The authors carried out RT-PCR for amplification of the RV nucleoprotein (N) gene, and determined 1,335 nucleotide sequences of N gene by direct sequencing method. Phylogenetic analysis, which was based on the N gene of Brazilian RV isolates identified presently and previously, revealed that RVs isolated from bats were genetically divided into four lineages had a tendency to depend on the host bat species. The first lineage consisted mainly of haematophagous bat (Desmodus rotundus) isolates, including frugivorous bat (Artibeus spp.) isolates. Other three lineages consisted of insectivorous bat isolates; mainly Eptesicus spp., Molossus spp. and Nyctinomops spp. isolates, respectively. These results indicate a possibility of that there are bat species-specific RV variants in Brazil.
Asunto(s)
Quirópteros/virología , Filogenia , Virus de la Rabia/genética , Rabia/epidemiología , Animales , Secuencia de Bases , Brasil/epidemiología , Análisis por Conglomerados , Cartilla de ADN , Geografía , Datos de Secuencia Molecular , Nucleoproteínas/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN , Especificidad de la EspecieRESUMEN
Rabies is carried mainly by mammalian carnivores and vampire bats in Latin America. However, rabies virus (RV) has been isolated in recent years from not only vampire bats in rural areas but also from several non-vampire bat species in urban areas, respectively. Therefore, rapid molecular screening is necessary for efficient epidemiology of these RVs. In this study, we investigated the usefulness of multiplex reverse transcription-polymerase chain reaction (RT-PCR) for determining the origins of 54 RV isolates from various host species in Brazil. And to evaluate the multiplex RT-PCR as a potential diagnostic tool, we investigated the sensitivity of this method. In addition, we compared the results with a phylogenetic tree developed from sequences of the RV glycoprotein (G protein) gene. Multiplex RT-PCR products showed five different sizes of products, whereas the phylogenic tree showed six groups. Of these six groups, four corresponded with the four sizes of the multiplex RT-PCR products. The other two groups showed correspondance with another one size of the multiplex RT-PCR products, indicating that multiplex RT-PCR results reflected the lineage of the 54 isolates. This study also showed that this method can detect trace amounts of RNA. In conclusion, this multiplex RT-PCR method allows the rapid, specific, and simultaneous detection of RVs isolated from various host species in Brazil.
Asunto(s)
Animales Domésticos/virología , Animales Salvajes/virología , Virus de la Rabia/clasificación , Rabia/epidemiología , Rabia/virología , Animales , Brasil/epidemiología , Enfermedades de los Gatos/virología , Gatos , Bovinos , Enfermedades de los Bovinos/virología , Quirópteros/virología , Enfermedades de los Perros/virología , Perros , Zorros/virología , Enfermedades de los Caballos/virología , Caballos , Humanos , Rabia/veterinaria , Virus de la Rabia/genética , Virus de la Rabia/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Especificidad de la Especie , Factores de TiempoRESUMEN
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.
Asunto(s)
Quirópteros/virología , Filogenia , Virus de la Rabia/genética , Animales , Secuencia de Bases , Encéfalo/virología , Brasil , Análisis por Conglomerados , Cartilla de ADN , Datos de Secuencia Molecular , Nucleoproteínas/genética , Análisis de Secuencia de ADN , Homología de SecuenciaRESUMEN
Genetic and phylogenetic analyses of the region containing the glycoprotein (G) gene, which is related to pathogenicity and antigenicity, and the G-L intergenic region were carried out in 14 Brazilian rabies virus isolates. The isolates were classified as dog-related rabies virus (DRRV) or vampire bat-related rabies virus (VRRV), by nucleoprotein (N) analysis. The nucleotide and amino acid (AA) homologies of the area containing the G protein gene and G-L intergenic region were generally lower than those of the ectodomain. In both regions, nucleotide and deduced AA homologies were lower among VRRVs than among DRRVs. There were AA differences between DRRV and VRRV at 3 antigenic sites and epitopes (IIa, WB+ and III), suggesting that DRRV and VRRV can be distinguished by differences of antigenicity. In a comparison of phylogenetic trees between the ectodomain and the area containing the G protein gene and G-L intergenic region, the branching patterns of the chiropteran and carnivoran rabies virus groups differed, whereas there were clear similarities in patterns within the DRRV and VRRV groups. Additionally, the VRRV isolates were more closely related to chiropteran strains isolated from Latin America than to Brazilian DRRV. These results indicate that Brazilian rabies virus isolates can be classified as DRRV or VRRV by analysis of the G gene and the G-L intergenic region, as well as by N gene analysis.
Asunto(s)
Antígenos Virales , Glicoproteínas/genética , Virus de la Rabia/genética , Proteínas del Envoltorio Viral/genética , Secuencia de Aminoácidos , Animales , Brasil , Gatos , Bovinos , Quirópteros , Cartilla de ADN , Perros , Epítopos , Genes Virales , Glicoproteínas/inmunología , Caballos , Humanos , Datos de Secuencia Molecular , Filogenia , ARN Viral/análisis , Virus de la Rabia/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Análisis de Secuencia de ADN/veterinaria , Homología de Secuencia de Aminoácido , Ovinos , Porcinos , Proteínas del Envoltorio Viral/inmunologíaRESUMEN
BACKGROUND: There is a geographical overlap between the two main rabies epidemiological cycles maintained by dogs and vampire bats in Latin America. The geographical and temporal coincidence of rabies outbreaks of respective origins is not unusual in rural areas of Latin America. These circumstances make it difficult to discriminate the intraspecies and interspecies transmission pathways of rabies. OBJECTIVE: This study was conducted to develop techniques to discriminate dog-related and vampire bat-related rabies virus isolates (DRRV and VRRV, respectively) in Brazil. STUDY DESIGN: The 1396 nucleotides of the nucleoprotein gene of a total of 27 DRRV and VRRV were sequenced. Strain-specific (SS) primers were developed based on these sequences. Forty-nine rabies virus strains isolated from animals and humans in several parts of Brazil were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) with SS primers. These rabies viruses were also amplified by RT-PCR with general rabies primers and the PCR products were cut by three restriction enzymes, Blp I, Bsu36 I and BspE I. RESULTS: All the DRRV and VRRV were distinguished by RT-PCR with SS primers. The PCR products obtained from DRRV were cut at one site by Blp I, but not by Bsu36 I. The PCR products obtained from VRRV were cut at one or two sites by Bsu36 I, but not by Blp I. Blp I and Bsu36 I clearly discriminated DRRV and VRRV in restriction fragment length polymorphysim (RFLP) assays. The results of SS RT-PCR and RFLP were consistent. CONCLUSION: SS RT-PCR and RFLP assays have been developed for determining the origins of rabies virus isolates in Brazil. These assays are simple and rapid, and will be useful for identifying the rabies virus reservoirs of field isolates in Brazil, especially when used together.