Borrelia theileri in ticks and cattle in a Caribbean area of Colombia

Some species of the Borrelia genus can infect animals, producing clinical signs and resulting in production losses. Borrelia theileri is the causative agent of bovine borreliosis and is transmitted by hard ticks, primarily Rhipicephalus microplus. The aim of this study was to detect B. theileri in R. microplus and cattle in some areas of the Córdoba department in Caribbean Colombia. In 2021 and 2022, ticks and whole blood were collected from Bos taurus and Bos indicus cattle in the department of Córdoba, Colombia. DNA was extracted from 913 ticks and 122 cattle blood samples were collected. Screening was performed using a Borrelia genus-specific qPCR for the 16S rRNA gene; positive samples underwent PCR for the 16S rRNA and flaB genes. The amplified products were Sanger sequenced. Alignments were performed, and phylogenetic trees were constructed using IQTREE2 and visualized and edited using ITOL. Borrelia spp. was detected in 13.9 % (17/122) of the cattle samples by qPCR. Using conventional PCR the 16SrRNA gene was detected in 23.5% (4/17) of the samples, while the flaB gene was not detected. Phylogenetic analyses of the 16SrRNA gene in cattle showed clustering with Borrelia sp. (MZ564265), B. theileri (MN619805) and close association with other B. theileri sequences (KAT KF569941, LC656247, MW562684, DQ872186, DQ872186). The ticks were taxonomically identified as R. microplus. The 16SrRNA gene of Borrelia spp. was detected by qPCR in 15.5% (35/225) of the samples. With conventional PCR, the 16SrRNA gene was detected in 37% (13/35) of the samples, and the flaB gene was detected in 5.7% (2/35). Sequencing was performed using flaB gene sequences of good quality. Phylogenetic analysis of the flaB gene showed that our sequences were grouped with Borrelia sp. (EF141022) and B. theileri (ON191583, C5 MG601737, KF569936). This is the first detection of B. theileri in ticks and the second in cattle in Colombia.