Characterizing the relationship between tick bites and Lyme disease in active component U.S. Armed Forces in the eastern United States.

Lyme disease (LD) is the most commonly diagnosed vector-borne illness in the U.S. Analysis of ticks that are removed from patients (rather than collected from the environment) may inform LD surveillance. In this ecological study, LD rates among active component U.S. Armed Forces in the eastern U.S. were compared with tick data from the U.S. Army Public Health Command Human Tick Test Kit Program (HTTKP) covering the same geographic region. In the population of service members in the study sample, mean annual LD incidence was 52.2 per 100,000 person-years (95% CI±; 7.6 per 100,000) between 1 January 2006 and 31 December 2012. A 10% increase in the rate of ticks submitted to the HTTKP corresponded to an increase in LD incidence of 5.7% (p<0.01). Where Borrelia burgdorferi infection of Ixodes scapularis ticks was high (20% or greater tick infection prevalence), tick removal rates explained 53.7% of the annual variation in LD incidence (p=0.01). These data support using location-specific rates of ticks removed while feeding on active component service members to complement LD surveillance.