Virus Research 153 (2010) 100–105 Contents lists available at ScienceDirect Virus Research journal homepage: www.elsevier.com/locate/virusres Human rabies transmitted by vampire bats: Antigenic and genetic characterization of rabies virus isolates from the Amazon region (Brazil and Ecuador) Juliana Galera Castilho a,* , Pedro Carnieli Jr. a , Ekaterina A. Durymanova a , Willian de Oliveira Fahl a , Rafael de Novaes Oliveira a , Carla Isabel Macedo a , Elizabeth Salbe Travassos da Rosa b , Anibal Mantilla c , Maria Luiza Carrieri a , Ivanete Kotait a a Pasteur Institute, Av. Paulista 393, Zip Code 01311-000, São Paulo, SP, Brazil b Evandro Chagas Institute, Pará, Brazil c Animal Health Laboratories/Leopoldo Izquieta Perez National Hygiene Institute, Quito, Ecuador article info Article history: Received 8 June 2010 Received in revised form 6 July 2010 Accepted 8 July 2010 Available online 15 July 2010 Keywords: Rabies Vampire bat Human Brazil Ecuador abstract Since 2004, the main transmitter of human rabies in Latin America has been the vampire bat (Desmodus rotundus). Based on the nucleoprotein of the rabies virus (RV), we analyzed antigenic and genetic profiles of isolates from 29 samples taken from humans living in different areas of the Amazon region. Two isolates were from Ecuador and 27 from the Northern and Northeastern regions of Brazil, which were obtained during outbreaks in various municipalities in the states of Pará and Maranhão in the years 2004 and 2005. The partial N gene (nt 104–1477) of the 29 isolates was sequenced, and the sequences were used to build a neighbor-joining tree with the Kimura-2 parameter model. All 29 human RV isolates were identified as belonging to antigenic variant 3 (AgV3) and were genetically grouped into the D. rotundus cluster, which was divided into two subclusters (A and B), subcluster A in turn being divided into four genetic groups (A1, A2, A3 and A4). Genetic and molecular markers characterizing these genetic lineages were also identified. The results of this study show that the isolates belong to the same rabies cycle as that of the vampire bat D. rotundus. However, the division of clusters within the lineage associated with D. rotundus shows that different genetic sublineages of the virus were circulating in the Amazon region during the study period. Our findings suggest that there are phylogeographic differences between isolates obtained over a short period. Published by Elsevier B.V. 1. Introduction Rabies is a cosmopolitan viral zoonosis that affects the central nervous system of mammals. It ranks 11th among infectious dis- eases in terms of human mortality (WHO, 2000). The World Health Organization estimates that 55,000 people die from this disease every year, primarily in Asia and Africa, where there are calculated to be 31,000 and 24,000 cases/year, respectively (WHO, 2005). The rabies virus (RV) belongs to the genus Lyssavirus, family Rhabdoviridae, and its genome is a single-stranded nonsegmented negative-sense RNA approximately 12 kb long that codes for five structural proteins (Fauquet et al., 2007). Reservoirs of the RV belong to the orders Carnivora and Chiroptera, which can transmit the disease to other mammals, including humans. The host species are distributed geographically according to their natural histories; * Corresponding author. Tel.: +55 11 31453172. E-mail address: juliana.castilho@uol.com.br (J.G. Castilho). consequently, the antigenic variants (AgV) and genetic lineages of RV circulate throughout a particular territory and can thus be iden- tified, as they are adapted to and maintained by different animal species distributed regionally (Childs and Real, 2007). In some countries that are endemic for canine rabies and where wildlife rabies is established (terrestrial and bats) the virus is main- tained in two main epidemiological cycles, one urban, in which dogs are the main reservoirs and transmitters, and the other syl- vatic, in which different species, such as bats and wild canids, are involved (Acha and Szyfres, 2003). Both urban and sylvatic rabies constitute important economic and public health problems in Latin America. While mass vaccination of cats and dogs has led to a fall in urban rabies, sylvatic rabies, particularly that transmitted by hematophagous bats, remains an emerging problem (Schneider et al., 2009). Humans have been bitten by vampire bats and thus been at risk of rabies transmission in Latin America for decades. Recently, how- ever, there has been an increasing number of reports of human rabies transmitted by the common vampire bat Desmodus rotun- 0168-1702/$ – see front matter Published by Elsevier B.V. doi:10.1016/j.virusres.2010.07.012