Dermacentor variabilis
variabilis" may be exposed to "Borrelia burgdorferi" , the causative agent of Lyme disease , these ticks are not competent vectors for the transmission of this disease . 
<triplet> Borrelia burgdorferi <subj> Lyme disease <obj> has effect <triplet> Lyme disease <subj> Borrelia burgdorferi <obj> has cause