Rocky Mountain spotted fever (RMSF) is a deadly tick-borne disease caused by the bacterium Rickettsia rickettsii. An ongoing epidemic of RMSF is affecting tribal communities in Arizona, with nearly 500 cases and 28 deaths since 2003. The San Carlos Apache Tribe has been consistently working to prevent RMSF using tick collars on dogs, pesticide treatments around homes, and increasing education for nearly a decade. Besides monitoring human disease levels and tick burden on dogs, we have little understanding of the long-term impact of prevention practices on tick abundance and infection rates in the peridomestic environment. We evaluated risk factors associated for tick infestation at home sites across the San Carlos Indian Reservation as well as R. rickettsii and Rickettsia massiliae prevalence in off-host ticks. Although the presence of fencing appears protective, the number of nearby structures is the most important risk factor associated with increased adult and nymphal tick abundance, highlighting the impact of a free-roaming dog population.

Rocky Mountain spotted fever (RMSF) is a severe tickborne disease that can reach epidemic proportions in communities with certain social and ecologic risk factors. In some areas, the case-fatality rate of brown dog tick-associated RMSF is up to 50%. Because of the spread of brown dog tick-associated RMSF in the southwestern United States and northern Mexico, the disease has the potential to emerge and become endemic in other communities that have large populations of free-roaming dogs, brown dog ticks, limited resources, and low provider awareness of the disease. By using a One Health approach, interdisciplinary teams can identify communities at risk and prevent severe or fatal RMSF in humans before cases occur. We have developed a conceptual framework for RMSF prevention to enable communities to identify their RMSF risk level and implement prevention and control strategies.