Possible post-infectious sequelae of tick-borne Rickettsia and Ehrlichia infections

To assess the presence of symptoms and immunological profiles after infection with tick-borne spotted fever rickettsiosis (SFR) or ehrlichiosis.

Adults evaluated for acute tick-borne disease completed symptom surveys through 90 days. Cases were classified using standard epidemiological definitions. Participants with alpha-gal sensitization were excluded from the primary analysis. Acute and convalescent cytokine profiles were compared between participants with and without symptoms present at the 90-day timepoint.

Among 71 participants, 37 (52.1%) and 33 (46.5%) met criteria for confirmed or probable ehrlichiosis and SFR, respectively; seven met criteria for both. After excluding 12 participants with alpha-gal sensitization, 15 (50.0%) with ehrlichiosis and 13 (50.0%) with SFR reported at least one moderate or severe symptom at 90 days, compared with one of eight (12.5%) participants classified as not a case. Fatigue and musculoskeletal pain were most common. Participants with symptoms present at 90-days showed higher pro-inflammatory and lower anti-inflammatory cytokine levels, but differences were not statistically significant.

Post-infectious syndromes after tick-borne disease may not be limited to Lyme disease. These preliminary findings support patient-reported experiences and warrant larger studies to define the prevalence, predictors, pathogenesis, and clinical course of possible persistent symptoms.