Clinical Manifestations, Risk Factors, and Disease Burden of Rickettsiosis, Cambodia, 2007-2020.

During 2007-2020, we conducted a cross-sectional prevalence study among patients with acute undifferentiated febrile illness to describe the burden and long-term epidemiology of rickettsioses in Cambodia. Serum samples were collected from 10,243 participants, along with epidemiologic data, information on clinical symptoms, demographic characteristics, and risk factors. A total of 802 (7.8%) participants met the definition for acute rickettsial infection after ruling out malaria, influenza, dengue, and chikungunya; 557 (5.4%) cases were typhus, 154 (1.5%) spotted fever, and 136 (1.3%) scrub typhus. Overall seroprevalence was 18.1% (1,857/10,243). Increased age, residence in urban settings, and recent travel to forests were significantly associated with rickettsial infection. Symptoms significantly associated with infection included rash, vomiting, and skin lesions. Our results confirm the underlying burden of rickettsioses and associated risk factors in Cambodia and highlight the need for accessible diagnostics and clinical guidance that consider rickettsioses when treating persons with acute undifferentiated febrile illness.