Coinfection of Bartonella spp. and Borrelia Burgdorferi in Ixodes Scapularis Using PCR Assay, a Case Study in Nova Scotia

Coinfection of vector species can provide more insight into the complex relationship between zoonotic pathogens and its host. Ixodes scapularis (Say) or the deer-tick in particular is an important species in North America because of its exceptional ability as a vector that can transmit zoonotic diseases such as Lyme and Cat Scratch Disease (CSD). In recent years, many studies have suggested a possible link between the coinfection of Borrelia burgdorferi, the causative agent of Lyme, with other tick-borne bacteria such as Bartonella spp., the causative agent of CSD, as partly responsible for the symptoms associated with Chronic Lyme Disease or Post-Treatment Lyme Disease Syndrome. This study investigates the prevalence of Bartonella spp. and Borrelia burgdorferi in Ixodes scapularis using Polymerase Chain Reaction (PCR) assay to potentially find a link between the two of the most common tick-borne pathogens found in Nova Scotia. Standard PCR using primers targeted at the two bacterial species were conducted on 157 I. scapularis ticks collected in Nova Scotia. Overall, we found high prevalence for both bacteria at 75.16% for Bartonella spp. and 47.13% for B. burgdorferi with no significant differences between the sex of the ticks. Interestingly, all the ticks positive for B. burgdorferi were also positive for Bartonella spp. which implies that the coinfection rate between B. burgdorferi and Bartonella spp. is 47.13%. We report one of the highest coinfection rates for B. burgdorferi and Bartonella spp. in I. scapularis, consistent with the current trends of increasing tick presence in North America.