First molecular evidence of potentially zoonotic Babesia microti and Babesia sp. EU1 in Ixodes ricinus ticks in Belgium

We report the first molecular evidence of the presence of Babesia sp. EU1 and Babesia microti in Ixodes ricinus ticks in Belgium. A 1-year national survey collected 1005 ticks from cats and dogs. A polymerase chain reaction technique amplifying a part of the 18S rRNA gene detected Babesia spp. in 11 out of 841 selected and validated tick extracts. Subsequent sequencing identified Ba. microti (n = 3) and Babesia sp. EU1 (n = 6). This study has demonstrated a low infection rate (1.31% with 95% CI: 0.65-2.33) of Babesia spp. carriage in I. ricinus ticks in Belgium but, for the first time, reports two potentially zoonotic species belonging to this genus. Coinfection with Ba. microti and Borrelia burgdorferi sensu stricto also was demonstrated. In addition, this study clearly demonstrates that inhibitors of polymerase chain reaction amplification are present in engorged ticks.