Detection of Borrelia in Ixodes scapularis ticks by silver stain, immunohistochemical and direct immunofluorescent methods

Background Lyme disease (LD) is one of the most common tick‐borne diseases caused by several Borrelia species of spirochetes. Ixodes scapularis is responsible for the transmission of LD in the northeastern United States. The rate of infection varies with the duration of tick attachment to the host; however, this information may be unknown. In skin biopsies, it is often difficult to identify spirochetes. Testing of ticks is not routinely performed. Treatment is established by clinical presentation. Objective To test paraffin‐embedded I. scapularis ticks for Borrelia by different methods. Materials/Methods We examined 20 paraffin‐embedded ticks by silver stain, immunohistochemical (IHC) and direct immunofluorescent (DIF) methods and compared the percentage of positivity with DIF results from the Connecticut Agricultural Experiment Station. Results The results were similar by DIF, which proved to be the most sensitive method, followed by the silver stain and IHC. Conclusion We found that the identification of spirochetes in paraffin‐embedded ticks was less difficult than in tissue with a comparable turnaround time to that of a routine biopsy. Timely identification of Borrelia in ticks may influence the clinical management of the patients.