Contents lists available at ScienceDirect Ticks and Tick-borne Diseases journal homepage: www.elsevier.com/locate/ttbdis Original article New records of tick-associated spotted fever group Rickettsia in an Amazon- Savannah ecotone, Brazil A.A.R. Aguirre a,e, ⁎ , Marcos Valério Garcia c , Ivaneide Nunes da Costa b,d , Bárbara Guimarães Csordas c,e , Vinícius da Silva Rodrigues c , Jansen Fernandes Medeiros b , Renato Andreotti c a Plataforma de Criação e Experimentação Animal, Fiocruz Rondônia, Oswaldo Cruz Foundation, n° 7671, Bairro Lagoa, Porto Velho, RO, CEP 76812-245, Brazil b Laboratório de Entomologia Médica, Fiocruz Rondônia, Oswaldo Cruz Foundation, Rua da Beira, n° 7671, Bairro Lagoa, Porto Velho, RO, CEP 76812-245, Brazil c Laboratórios de Biologia Molecular e do Carrapato, Brazilian Agricultural Research Corporation, Av. Rádio Maia, n° 830, Zona Rural, Campo Grande, MS, CEP 79106- 550, Brazil d Programa de Pós-Graduação em Biologia Experimental, Universidade Federal de Rondônia, Rodovia BR 364, Km 9,5, Porto Velho, RO, CEP 76801-059, Brazil e Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Universidade Federal de Mato Grosso do Sul, Av. Costa e Silva, Bairro Universitário, Campo Grande, MS, CEP 79070-900, Brazil ARTICLE INFO Keywords: Brazilian spotted fever Rickettsia amblyommatis Amblyomma oblongoguttatum Amazon-Savanna ecotone ABSTRACT Human rickettsiosis has been recorded in the Amazon Biome. However, the epidemiological cycle of causative rickettsiae has not been fully accounted for in the Amazon region. This study investigates the presence of spotted fever group (SFG) Rickettsia spp. in free-living unfed ticks of the Amblyomma genus. The study was conducted in seven municipalities in Rondonia State, Brazil, where the main biomes are Amazon forest, Brazilian Savannah and their ecotones (areas of ecological tension between open ombrophilous forest and savannah). The following tick species were collected: Amblyomma cajennense (sensu lato) s.l., A. cajennense (sensu stricto) s.s., A. coelebs, A. naponense, A. oblongoguttatum, A. romitii, A. scalpturatum and A. sculptum. A total of 167 adults, 248 nymphs and 1004 larvae were subjected to DNA extraction and polymerase chain reaction (PCR) to determine the presence of SFG Rickettsia spp. PCR-positive samples included: one A. cajennense s.s. female and one A. cajennense s.l. male from a rural area in Vilhena Municipality; 10 nymphs and a sample of larvae of A. cajennense s.l. from a peri- urban area in Cacoal Municipality; and an A. oblongoguttatum adult male from a rural area of Pimenta Bueno Municipality. All sequences obtained exhibited 100% identity with Rickettsia amblyommatis sequences. This is the first confirmation of SFG Rickettsia in an A. oblongoguttatum tick. Furthermore, this is the first record of SFG Rickettsia in the municipalities targeted by this study. These results warn that SFG Rickettsia circulation poses a threat in Rondonia State (among Amazon-Savannah ecotones), and that this threat is increased by the fact that SFG Rickettsia infect a human-biting tick species hitherto unconfirmed as a vector. 1. Introduction Rickettsia is a genus of bacteria of the order Rickettsiales, α- Proteobacteria subgroup. These bacteria are obligate intracellular Gram-negative Coccobacilli (Parola et al., 2005). This genus includes: typhus group (TG), comprised of Rickettsia typhi and R. prowazekii; and spotted fever group (SFG), which includes several species, R. rickettsii being the most lethal (Raoult and Roux, 1997; Gillespie et al., 2007; Weinert et al., 2009; Tarragona et al., 2015). In Brazil, SFG Rickettsia spp. infection is transmitted to humans by ticks. The primary transmission vectors are: Amblyomma sculptum, in the Brazilian Savannah biome; and A. aureolatum, in the Atlantic rain- forest biome (Labruna, 2009). SFG Rickettsia spp. have been detected in several species of the Amblyomma genus; some of these species para- sitize dogs and humans, and some have already been recorded in Rondonia State (Labruna et al., 2004a,b, 2005a,b, 2007; Barbieri et al., 2008; Szabó et al., 2013; Martins et al., 2014; Oliveira et al., 2016a,b). The Amblyomma spp. fauna is more diversified in the western Amazon than in other regions of Brazil (Martins et al., 2014). Although many studies of the tick fauna and SFG Rickettsia have been conducted in this region, little is known about the dynamic dispersion of these pathogens and their relation to human illness is poorly understood https://doi.org/10.1016/j.ttbdis.2018.03.015 Received 30 June 2017; Received in revised form 11 March 2018; Accepted 12 March 2018 ⁎ Corresponding author at: Plataforma de Criação e Experimentação Animal, Fiocruz Rondônia, Oswaldo Cruz Foundation, Rua da Beira n° 7671, Bairro Lagoa, Porto Velho, RO, CEP 76812-245, Brazil. E-mail address: andre.aguirre@fiocruz.br (A.A.R. Aguirre). Ticks and Tick-borne Diseases 9 (2018) 1038–1044 Available online 22 March 2018 1877-959X/ © 2018 Elsevier GmbH. All rights reserved. T