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Abstract
Rocky Mountain spotted fever (RMSF) is a life-threatening tickborne disease, caused by the bacterium Rickettsia rickettsii. Illness begins with non-specific symptoms, such as fever, headache, and muscle pain, but progresses rapidly. When left unmitigated, the bacteria can damage the cells lining small blood vessels resulting in organ failure, sepsis, and ultimately death. Patients who survive severe RMSF infections may be left with permanent disability including organ damage, necrosis of extremities requiring amputation, and neurologic deficits. Few studies have described the long-term sequelae (LTS) from RMSF and little is known about the persistence of such sequelae nor the impact of such disabilities on patients and families. This dissertation describes a cohort of individuals hospitalized for RMSF in two Arizona communities to assess the presence, persistence, and relative cost of neurologic sequelae years following infection. Acute disease is described from medical records. Surviving individuals were interviewed about their disease recovery and individuals reporting ongoing symptoms were assessed by a neurologic exam. Twenty-three percent of individuals interviewed showed signs of LTS on exam. Delayed antibiotic therapy was the single most important predictor of LTS. Evidence of long-term disability following RMSF emphasizes the severe and potentially life-long consequences of delayed recognition and treatment. Furthermore, such evidence draws attention to the potential long-term care required to support individuals during their recovery. Arizona tribal communities have been substantially impacted by RMSF but may lack the resources for long-term morbidity management in the wake of epidemic disease. A second study compares the cost of acute care using flat-rate charges in the Arizona tribal cohort and to medical billing information from two large national databases. Average direct costs per hospitalized case of RMSF ranged from $16,894-$25,573 among the three sources. Finally, total disease impact is described in terms of disability-adjusted life years (DALYs) lost from RMSF. Estimates for the Arizona cohort included 516 DALYs lost, representing substantial morbidity and mortality in small tribal communities. Descriptions of disease burden can help policy makers evaluate the relative importance of RMSF prevention and may help prioritization of long-term medical support systems for highly impacted communities.