The skin of outdoor workers in North Carolina

Background: tick-transmitted rickettsial diseases,such as ehrlichiosis and spotted fever rickettsiosis,are significan sources of morbidity and mortality in the southern united states. because of their exposure in tick-infested woodlands outdoor workers experience an increased risk of infection with tick-borne pathogens. as part of a doubl blind randomized-controlled field trial of the effectiveness of permethrin-treated clothing in preventing tic bites,we identified tick species removed from the skin of outdoor workers in north carolina and tested th ticks for rickettsiales pathogens methods: ticks submitted by study participants from april-september 2011 and 2012 were identified to species an life stage,and preliminarily screened for the genus rickettsia by nested pcr targeting the 17-kda protein gene rickettsia were further identified to species by pcr amplification of 23s-5s intergenic spacer (igs) fragment combined with reverse line blot hybridization with species-specific probes and through cloning and nucleotid sequence analysis of 23s-5s amplicons. ticks were examined for ehrlichia and anaplasma by nested pcr directed at th glta,antigen-expressing gene containing a variable number of tandem repeats,16s rrna,and groesl genes results: the lone star tick (amblyomma americanum) accounted for 95.0 and 92.9% of ticks submitted in 201 (n = 423) and 2012 (n = 451),respectively. specimens of american dog tick (dermacentor variabilis),gulf coas tick (amblyomma maculatum) and black-legged tick (ixodes scapularis) were also identified. in both years o our study,60.9% of ticks tested positive for 17-kda. candidatus rickettsia amblyommii