LAUSR

BACKGROUND Dengue and chikungunya co-infections are an emerging threat to public health in tropical and sub-tropical areas. This study investigates acute and long-term clinical presentation patterns of chikungunya against a backdrop of preceding dengue infection and determines predicting factors for long-term chikungunya sequelae. METHODS A retrospective cohort study was performed in 2015, including 299 previously confirmed chikungunya cases, of which 162 subjects were assessed for dengue serology at disease onset. RESULTS Those with previous dengue infection (35.2% of the examined population) had a similar acute disease presentation, and suffered (not statistically significantly) more frequently from long-term musculoskeletal and neuropsychological symptoms compared to chikungunya-only patients. Patients with a preceding dengue infection (vs. those without) (OR = 4.17; p = 0.004), female sex (OR = 3.17; p = 0.034) and pre-existing joint disease (OR = 2.95; p = 0.031) had a higher risk of developing aggravated long-term chikungunya. Chronic disease (sequelae lasting >90 days) was predicted by an age between 41 and 60 (OR = 3.07; p = 0.009) and concomitant cardiovascular disease (OR = 4.08; p = 0.010), but not by a preceding dengue infection. CONCLUSIONS This study suggests several predicting factors of, and a possible link between preceding dengue and chikungunya infection and aggravated long-term sequelae, which should be interpreted in the light of the limitations of this study.