Classification of chikungunya cases: a proposal.

Since 2005, chikungunya virus (CHIKV) has caused large outbreaks, with reports of more than 10 million cases worldwide over the course of a decade. Since 2013, almost three million cases have been reported in the Americas. Although musculoskeletal involvement is the most prevalent symptom in the disease spectrum, systemic manifestations with involvement of important organs have also been described. Currently, case classifications of chikungunya based on the intensity and duration of articular symptoms have been used to guide the clinical management of the joint manifestations, with little or no emphasis on the severe clinical forms associated with systemic disease and target organ involvement. Thus, these classifications have failed to aid health professionals in the detection and early management of severe cases, which can lead to fatal outcomes and sequelae. Based on data from international literature and the opinions of clinical professionals, epidemiologists, and arbovirologists with extensive experience gained from the Brazilian chikungunya outbreak, a group of specialists proposed a revised classification for chikungunya cases. In this proposed classification, the specialists highlight the different patterns of the disease, including systemic manifestations, with the aim of sensitizing health professionals for the prompt detection and early management of severe conditions, which can contribute to reducing fatal outcomes.