RESUMO
Background: Lyme disease, caused by infection with Borrelia burgdorferi, is the most common vector-borne disease in the United States. The standard two-tier testing (STTT) algorithm suffers from low sensitivity, misinterpretation, and long turnaround time, preventing timely detection and treatment. To address these challenges, we hypothesized that the canine point-of-care (PoC) SNAP 4Dx Plus test used to detect Borrelia burgdorferi antibodies could be employed for human diagnosis. Materials and Methods: The SNAP 4Dx Plus testing was conducted in accordance with the manufacturer's instructions, with results read by manual inspection. All analyses were conducted using R version 4.3.1, and agreement between the PoC assay and the STTT was assessed using kappa statistics with GraphPad software. Results: We included 102 previously-tested human serum samples, of which 19 samples (18.6%) were STTT positive. Compared to the STTT, the SNAP 4Dx Plus test demonstrated a low sensitivity of 0.16 (95% CI 0.03 to 0.40). Conclusion: Overall, our results do not support the use of the SNAP 4Dx Plus LD assay for the diagnosis of human Lyme disease. Differences in antibody concentrations between human and canine samples may partly explain our findings.
RESUMO
We obtained samples from the Department of Defense Serum Repository from soldiers who were stationed at Fort Liberty, North Carolina, between 1991 and 2019 to assess temporal trends in tick-borne rickettsiosis and ehrlichiosis. Serological evidence of infection was common, with nearly 1 in 5 (18.9%) demonstrating antibodies. We observed significant decreases in Rickettsia seroprevalence (adjusted odds ratio [aOR], 0.42 [95% CI, .27-.65], P = .0001) while over the same period Ehrlichia seroprevalence, albeit less common, nearly doubled (aOR, 3.61 [95% CI, 1.10-13.99], P = .048). The increase in Ehrlichia seroprevalence likely reflects increased transmission resulting from the expanding geographic range of the lone star tick.
