Candidatus Rickettsia colombianensi in ticks from reptiles in Córdoba, Colombia

Abstract

Background and Aim: Wildlife animals are reservoirs of a large number of microorganisms pathogenic to humans, and ticks could be responsible for the transmission of these pathogens. Rickettsia spp. are the most prevalent pathogens found in ticks. This study was conducted to detect Rickettsia spp. in ticks collected from free-living and illegally trafficked reptiles from the Department of Córdoba, Colombia. Materials and Methods: During the period from October 2011 to July 2014, ticks belonging to the family Ixodidae were collected, preserved in 96% ethanol, identified using taxonomic keys, and pooled (between 1 and 14 ticks) according to sex, stage, host, and collected place for subsequent DNA extraction. Rickettsia detection was performed using real-time polymerase chain reaction (RT-PCR), followed by conventional PCR to amplify a larger fragment of the gltA and 16S rRNA genes. The amplicons were sequenced using the Sanger method, and the nucleotide sequences were subjected to BLAST analysis to identify homologous sequences in GenBank, after which phylogenetic analysis was performed using the MEGA X software. Results: In total, 21 specimens of nine species of reptiles were sampled, from which 805 Amblyomma dissimile ticks were collected, but only 180 ticks were selected to create 34 groups. The DNA of Rickettsia spp. was detected in 30/34 (88%) groups. The sequences of the gene gltA and 16S rRNA revealed a 100% identity with Candidatus Rickettsia colombianensi (GenBank: KF905456 and GenBank: KF691750). Conclusion: A. dissimile was the only tick found in all the sampled reptiles. The presence of Candidatus Rickettsia colombianensi in reptile ticks could represent a public health problem due to the risk of transmission to humans and the introduction of microorganisms to other geographical areas.