SEDSS, operated by the Centers for Disease Control and Prevention (CDC) and the Puerto Rico Department of Health (PRDH), is a platform to conduct population-based studies to better define the etiology and epidemiology of dengue-like acute febrile illnesses. For the purposes of this investigation, CHIKV cases will be defined as patients enrolled in the SEDSS who had laboratory evidence of CHIKV infection (e.g., anti-CHIKV IgM, RT-PCR), and CHIKV severity cases are defined as those who they were admitted to hospital and hospitalized. to the intensive care unit (ICU) or died. This descriptive analysis will provide information on the demographic profile, underlying medical conditions, clinical characteristics, reasons and duration of hospitalization, and patient outcome. The results of this investigation will be used to help physicians and other healthcare professionals better understand the clinical course of chikungunya patients and also to improve patient management by reducing excessive hospitalization associated with