Rickettsial Infection in Ticks from a National Park in the Cerrado Biome, Midwestern Brazil

• DOI: 10.3390/pathogens13010013
• Publication Date: 2023-12-22T09:44:40Z
• Authors: Raquel Loren dos ...; Warley Vieira de ...; Lucianne Cardoso ...; Luiza Gabriella F...; Nicolas Jalowitzk...; Bianca Barbara Fo...; Brenda Gomes Pereira; Gracielle Teles P...; Filipe Dantas-Torres; Marcelo B. Labruna; Thiago Fernandes ...; Jonas Sponchiado; Lucas Christian d...; Wellington Hannibal; Felipe da Silva K...
• Keywords: <i>Rickettsia parkeri</i>; <i>Rickettsia tillamookensis</i>; 03 medical and health sciences; 0302 clinical medicine; <i>Amblyomma sculptum</i>; R; Medicine; <i>Amblyomma triste</i>; Article

This study was carried out from February 2020 to September 2021 in Parque Nacional das Emas (PNE), a national park located in the Cerrado biome, midwestern Brazil, as well as in surrounding rural properties. Serum and tick samples were collected from dogs, terrestrial small mammals, and humans. Ticks were also collected from the environment. Dogs were infested with Rhipicephalus linnaei adults, whereas small mammals were infested by immature stages of Amblyomma spp., Amblyomma triste, Amblyomma dubitatum, and Amblyomma coelebs. Ticks collected from vegetation belonged to several species of the genus Amblyomma, including A. coelebs, A. dubitatum, Amblyomma naponense, Amblyomma sculptum, and A. triste. Two Rickettsia species were molecularly detected in ticks: Rickettsia parkeri in A. triste from the vegetation and a Rickettsia sp. (designated Rickettsia sp. strain PNE) in A. sculptum and A. triste collected from lowland tapirs (Tapirus terrestris). Based on short gltA gene fragments, this rickettsial organism showed 99.7–100% to Rickettsia tillamookensis. Seroreactivity to Rickettsia antigens was detected in 21.9% of dogs, 15.4% of small mammals, and 23.5% of humans. The present study reveals the richness of ticks and demonstrates the circulation of rickettsial agents in one of the largest conservation units in the Cerrado biome in Brazil. To our knowledge, this is the first report of a rickettsial phylogenetically related to R. tillamookensis in Brazil.