Molecular Characterization and Epidemiology of Anaplasmataceae in Ticks and Domestic Animals in the Colombian Caribbean

Tick-borne diseases (TBD) pose a significant threat to both animal and public health, particularly in tropical regions. In the Colombian Caribbean region, there is limited knowledge of the epidemiology of TBD in domestic animals and their vectors. In this study, conducted in northern Colombia from 2021 to 2022, we analyzed the molecular diversity of Anaplasmataceae in a total of 1156 ticks and blood samples collected from their infested hosts: 56 cattle and 17 equids (horses and mules). Polymerase chain reaction (PCR) assays were performed, using primers to amplify the mitochondrial 16S rRNA gene for tick identification and bacterial 16S and 23S rRNA to detect Anaplasmataceae. The amplified products were sequenced and analyzed for molecular characterization of species. Four tick species were identified: <i>Dermacentor nitens</i> (55.6%), <i>Rhipicephalus microplus</i> (43.0%), <i>Rhipicephalus sanguineus</i> sensu lato (0.7%), and <i>Amblyomma patinoi</i> (0.7%). Overall, 9.4% of the pooled tick samples were identified as <i>R. microplus</i>, and 64.4% of the blood samples tested positive for Anaplasmataceae. Molecular analyses identified <i>Anaplasma marginale</i> in cattle and several species in ticks, including an <i>Anaplasma</i> sp. closely related to <i>A. platys</i>-like, <i>Ehrlichia ruminantium</i>, and <i>E. muris</i> and <i>Ehrlichia</i> variants closely related to <i>Candidatus</i> E. rustica, <i>E. canis</i>, and <i>E. minasensis</i>. The results indicate high infection rates and the circulation of both well-known and potentially novel Anaplasmataceae species, suggesting complex transmission dynamics among ticks and hosts.