The increased incursion of the human population into formerly wild and rural areas during the latter half of this century has precipitated enhanced awareness of, and concern for, pathogens transmitted by ticks.<sup>63 Spach D.H., Liles W.C., Campbell G.L. , e al. Tick-borne diseases in the United States N Engl J Med 1993 ;  329 : 936-947  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 71 Walker D.H., Dumler J.S. Emergence of the ehrlichioses as human health problems Emerg Infect Dis 1996 ;  2 : 18-29  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> In addition to established diseases, like Rocky Mountain spotted fever (RMSF), tularemia, and relapsing fever, tick-borne infections, such as Lyme disease and babesiosis, have been newly described since 1975. Among these emerging tick-borne diseases are two clinically similar and geographically diverse illnesses caused by rickettsia of the genus Ehrlichia, recently recognized as agents of human disease in the United States.