Multiplexed high-definition PCR assay for the diagnosis of tick-borne infections in children

Abstract Background Ixodes scapularis ticks can carry Borrelia species as well as other pathogens that cause human disease. The frequency of tick-borne infections and co-infections in children with suspected Lyme disease is unknown, creating clinical uncertainty about the optimal approach to diagnosis. Methods We enrolled children aged 1 to 21 years presenting to one of eight Pedi Lyme Net emergency departments for evaluation of Lyme disease. We selected cases with serologically or clinically diagnosed Lyme disease (erythema migrans or early neurologic disease) matched by symptoms, age, gender and center to control subjects without Lyme disease. We tested whole blood samples collected at the time of diagnosis using a high-definition multiplex polymerase chain reaction (HDPCR) panel to identify 9 bacterial or protozoan pathogens associated with human disease. We compared the frequency of tick-borne co-infections in children with Lyme disease to matched controls. Results Of the 612 selected samples, 594 (97.1%) had an interpretable multiplex HDPCR result. We identified the following non-Borrelia tick-borne infections: Anaplasma phagocytophilum (2), Ehrlichia chaffeensis (1) and Babesia microti (12). Children with Lyme disease were more likely to have another tick-borne pathogen identified than matched controls [15/297 (5.1%) Lyme cases vs. 0/297 (0%); difference 5.1% 95% CI 2.7, 8.2%). Conclusions Although a substantial minority of children with Lyme disease had another tick-borne pathogen identified, either first-line Lyme disease antibiotics provided adequate treatment or the coinfection was subclinical and did not require specific treatment. Further studies are needed to establish the optimal approach to testing for tick-borne co-infections in children.