Identification of Factors Associated With Chronic Chikungunya Disease in Patients in Grenada, West Indies

Abstract

Chikungunya virus (CHIKV) is a rapidly re-emerging arboviral pathogen worldwide. In July 2014, an explosive CHIKV outbreak occurred in Grenada, West Indies, infecting around 90% of the population, with a wide spectrum of disease reported. In an estimated 50% of cases, CHIKV infection transitions to a non-communicable painful arthritis that can persist for years. Our understanding of the risk factors and mechanisms underlying chronic disease are limited. Here, we conducted one-year follow up with 240 people who were tested for CHIKV during the Grenada outbreak and performed analyses on demographic, behavioral, exposure, and co-morbid health factors to identify associations with chronic disease. Physical examinations were performed and current arthritis/arthralgia symptoms, as well as prior medical history was recorded. Participants also completed extensive questionnaires so that physical, psychological, social and environmental factors could also be assessed. "Chronic" CHIKV disease cases were defned as individuals who continue to experience arthralgia and/or arthritis >6 months after onset of their acute CHIKV disease that impacts activities of daily living. Demographic factors including age (p=0.56), gender (0.058), ethnicity (0.58) and socioeconomic status did not have an effect on the likelihood of suffering from chronic persistent CHIKV disease. Increased mosquito avoidance behavior also did not reduce the risk of chronic sequelae. Patients who suffered joint pains (0.005), muscle pains (0.042), generalized body ache (0.013) and weakness in the extremities (0.013) during acute CHIKV disease were more likely to have chronic arthritis and arthralgia symptoms, and an increased duration of acute disease (0.001) also increased risk. None of the co-morbidities measured were associated with increased disease risk. These data demonstrate that chronic CHIKV disease affects people across the age, gender, ethnic and socioeconomic spectrum, and is not reduced by vector avoidance activity. Management of acute symptoms and minimization of acute disease duration could reduce chronic sequelae.