P4.059: Trends and Patterns of Lyme Disease in Kentucky

Background: Lyme Disease (LD) is the most common tickborne illness in the US and changes in regional weather patterns have expanded tick populations. Although the state of Kentucky has been considered a ‘low-incidence’ state for LD, recent patterns with respect to pediatric illness have not been conducted and the impact of increasing rates of LD on children is not well defined. Perceptions of rising pediatric Lyme arthritis cases noted by Pediatric Rheumatology at the University of Kentucky Healthcare suggests a significant proportion of this increase is manifesting as arthritis, a late-stage process that can be prevented with earlier diagnosis and treatment. We conducted a collaborative study to evaluate prevalence of tick populations in our region, clinical manifestations of LD, and patterns in LD testing and positivity rates in patients cared for at our regional academic medical center.

Methods: Tick counts were determined via field studies and standardized environmental assessment methodologies. Medical data were extracted from institutional EMR via ICD10 codes and positive two-tiered/modified two-tiered testing related to LD. De-identified patient data from 2021-2024 were investigated with respect to patient sex, age, residential county, and LD manifestation.

Results: Surveillance for Ixodes scapularis (primary LD vector) showed a recent increased presence in 58 of 120 counties in Kentucky, with most of them in proximity to our medical center. From 2021-2024, our academic medical center performed 1061 clinical tests for LD, with a downward trend in numbers of tests annually. For both children and adults, there was a significant increase in cases over time (two-fold increase in adults, four-fold increase in children; p < 0.05). Adult patients (>18 years) had annual positivity LD test rates of 4-8%. There was a significant difference in proportion of female-to-male diagnoses in adult vs pediatric cases, with adults exhibiting a higher incidence in females (p < 0.05). LD-related arthritis was identified in 27% of the pediatric cases, but only 4% of adult cases (p < 0.05).

Conclusion: These data support the general conclusion that LD is on the rise in Kentucky in both children and adults. However, children more often suffer from late manifestations as compared to adults. Possible contributing factors to the increase in case numbers include change in testing methods (transition from standard to modified two-tier testing), different practices in antibiotic prescription (provider hesitancy to use doxycycline in young children) and potential environmental factors. Earlier recognition of LD may prevent later complications, such as Lyme arthritis. Further investigation of LD patterns, as well as enhanced messaging to families and healthcare providers regarding the increase in LD in our region is indicated.