Rabia transmitdaa por murciélagos enBBrasil / Rabies Transmitted by Bats in Brazil

Frente al desafío que la rabia representa para la industria pecuaria y la salud pública en América Latina, el presente artículo tiene como objetivo hacer una revisión de literatura amplia y crítica sobre la epidemiología de la rabia transmitida por murciélagos en Brasil. El tema es abordado inicialmente desde una perspectiva histórica hasta la caracterización molecular de aislamientos del virus, para finalmente contrastar con la situación de otros países de las Américas. La información referente a Brasil es presentada de manera separada debido a la gran abundancia de especies de murciélagos de diversos hábitos alimenticios, implicadas en la transmisión del virus de la rabia y las complejas relaciones entre los ciclos epidemiológicos revelados por estudios de tipificación antigénica y análisis filogenético, lo cual ha permitido reconocer con más nitidez, la importancia de los quirópteros como reservorios y transmisores de esta enfermedad. Este nuevo escenario epidemiológico exige reexaminar las medidas de control aplicadas hasta el momento, desde un abordaje multidisciplinar, así como cooperación intersectorial y participación por parte de la comunidad.

Considering that rabies represents a challenge for the livestock industry and public health in Latin America, this article is intended to do a comprehensive and critical literature review on the epidemiology of rabies transmitted by bats in Brazil. The subject is addressed from a historical perspective to molecular characterization of rabies virus isolates and finally making a contrast with other countries of the Americas. Information concerning Brazil is presented separately because of the abundance of bats species with different feeding habits, involved in the transmission of rabies virus and the complex relationships between epidemiological cycles in this country, which have been disclosed by antigenic typing and phylogenetic analysis. This has allowed to recognize more clearly the importance of bats as reservoirs and transmitters of this disease. This new epidemiological scenario requires reappraising current control measures, using a multidisciplinary approach, intersectoral cooperation and community participation.

Murciélagos hematófagos como reservorios de la rabia / Hematophagous bats as reservoirs of rabies

La rabia continua siendo un desafío para las autoridades de salud pública y una limitante para la industria ganadera en América Latina. Caninos silvestres y domésticos, así como murciélagos hematófagos son las principales especies transmisoras y reservorios de la enfermedad. Actualmente, se observa variaciones en el perfil epidemiológico de la rabia, donde la especie de murciélago hematófago Desmodus rotundus se constituye en la principal especie transmisora. A lo largo del tiempo se ha acumulado conocimiento sobre la ecología, biología y comportamiento de esta especie y sobre la historia natural de la rabia, lo cual debe conducir a una continua evolución de los métodos de control poblacional de D. rotundus, prevención y técnicas de diagnóstico. Aún se desconoce la relación ecológica de esta especie con otras hematófagas y no hematófagas, y queda mucho por mejorar en los sistemas de notificación y vigilancia epidemiológica, así como crear una mayor conciencia entre los ganaderos ante el tema. La comprensión del impacto que las modificaciones ambientales inducidas por el hombre ejercen sobre la dinámica de infección del virus de la rabia en los murciélagos debe ser motivo de investigaciones posteriores. Esto requerirá la combinación de estudios de campo con modelos matemáticos y nuevas herramientas diagnósticas. La presente revisión pretende presentar los aspectos más relevantes sobre el rol de los murciélagos hematófagos como reservorios y transmisores del virus de la rabia.

Rabies continues to be a challenge for public health authorities and a constraint to the livestock industry in Latin America. Wild and domestic canines and vampire bats are the main transmitter species and reservoirs of the disease. Currently, variations observed in the epidemiological profile of rabies, where the species of hematophagous bat Desmodus rotundus constitutes the main transmitting species. Over the years, knowledge has accumulated about the ecology, biology and behavior of this species and the natural history of rabies, which should lead to continuous development of methods of population control of d. Rotundus as well as prevention and diagnostic tools for rabies. Ecological relationships of this species with other hematophagous and non-hematophagous bats is unknown, and there is much room for improvement in reporting systems and surveillance, as well as creating greater awareness among the farming community. Understanding the impact of human-induced environmental changes on the rabies virus in bats should be cause for further investigation. This will require a combination of field studies with mathematical models and new diagnostic tools. This review aims to present the most relevant issues on the role of hematophagous bats as reservoirs and transmitters of the rabies virus.

A semi-nested RT-PCR assay targeted to hemagglutinin-esterase gene of Bovine Coronavirus / Reação de hemi-nested RT-PCR dirigida ao gene da hemaglutinina-esterase do Coronavírus Bovino

Bovine coronavirus (BCoV) is a non-segmented positive-sense single-stranded RNA virus whose envelope is constituted by a lipid bilayer with four structural proteins (HE, S, E and M) giving its characteristic crown-like virions appearance. Hemagglutinin-esterase (HE), is a polymorphic protein with a function of secondary receptor binder, and studies on the diversity of HE gene allow insights on BCoV evolution and host-parasite interactions. A semi-nested RT-PCR was developed for the amplification of a 441bp-long product of the HE gene of BCoV (nt 543 to 562). Optimal annealing temperatures were tested in a gradient thermocycler for the semi-nested assay and employed in the final protocol. The analytical sensitivity was determined by 10-fold serial dilutions of the BCoV Kakegawa strain (HA titer: 256) in a BCoV-free fecal suspension, with positive results up to 10-6 dilution, a high analytical sensitivity without PCR inhibition. The final semi-nested RT-PCR protocol was applied to 21 fecal samples of cows previously positive to BCoV and DNA sequencing of the 441bp amplicons of 14 of these resulted in highly-scored BCoV HE gene sequences after BLAST/n analysis. This semi-nested RT-PCR is a powerful tool for surveys of phylogenetic diversity in field strains of BCoV and for comparative studies among different genes of Coronavirus.

O coronavírus bovino (BCoV) é um vírus RNA simples fita, de sentido positivo, não segmentado com envelope constituído de uma camada dupla de lipídios com quatro proteínas (HE, S, E e M) que resultam no aspecto de coroa dos vírions. Como a HE (hemaglutinina-esterase) é uma proteína polimórfica com uma função de receptor aglutinante secundária, estudos sobre a diversidade do gene HE podem possibilitar maiores informações sobre a evolução e interação hospedeiro-parasita do BCoV. Uma reação de hemi-nested RT-PCR foi desenvolvida para a amplificação de um produto de 441pb do gene HE do BCoV (nt 543 ao 562). Temperaturas ótimas de hibridização foram testadas em um termociclador com gradiente para a reação de hemi-nested e utilizada no protocolo final. A sensibilidade analítica foi determinada por meio da diluição serial na base 10 do BCoV amostra Kakegawa (título HA: 256) em uma suspensão fecal negativa para BCoV, resultando positiva até a diluição de 10-6, mostrando uma alta sensibilidade analítica sem inibição na PCR. O protocolo final da hemi-nested RT-PCR foi aplicado a 21 amostras fecais de vacas previamente positivas para BCoV e o sequenciamento de DNA do produto de 441pb de 14 amostras resultaram em sequências com elevado escore do gene HE do BCoV após a análise no BLAST/n. Essa hemi-nested RT-PCR é uma ferramenta poderosa para estudos de diversidade filogenética de linhagens de campo de BCoV e para estudos comparativos entre os diferentes genes dos Coronavírus.

Differentiation of Bovine coronavirus (BCoV) genotypes by a restriction enzyme assay

This article reports the use of the GsuI restriction enzyme to differentiate genotypes of Bovine Coronavirus (BCoV), based on an 18-nucleotide deletion of S1-coding region found in one of the two genotypes. It was concluded that this assay can be used as a rapid tool for BCoV genotypes differentiation.