Prevalence of Babesia microti in Ixodes Ticks in Southeast Virginia

Human babesiosis is a disease caused by an infection with the protozoan pathogen, Babeisa microti (Ba. microti). In the USA, Ba. microti is primarily transmitted through the bite of an infected Ixodes scapularis tick. Ixodes scapularis, as well as the related vector, Ixodes affinis, are well established in southeastern Virginia. Though Ixodes affinis are not reported to bite humans, it is possible that they play an important role in maintaining pathogens like Ba. microti in their sylvatic cycles. This study examines the prevalence of this pathogen within Ixodid ticks collected in southeastern Virginia. Questing I. scapularis and I. affinis were collected by flagging various field sites from 2010 to 2017. The prevalence of Ba. microti in the ticks was determined by screening extracted DNA from the collected ticks, using real-time PCR. Positive results were then confirmed by sequencing mitochondrial 18s rRNA. This study shows that Ba. microti-infected ticks are present in Virginia, where human babesiosis is considered a rare disease. In addition, Ba. microti was detected in I. affinis, where it has not previously been reported. The interactions between the two tick species that share hosts may be driving an increase in the natural reservoir of tick-borne pathogens like Ba. microti. Further research and active surveillance is needed to understand the contribution of I. affinis to the ecology of Ba. microti