Chikungunya in Colombia: a description of an epidemic within the framework of a COPCORD study

During 2014 and 2015 the chikungunya virus reached Colombia unleashing an epidemic that spread throughout the whole territory. Concurrently, the Colombian Rheumatology Association was conducting a Community Oriented Program for Control of Rheumatic Diseases (COPCORD) to establish rheumatic disease prevalence in the country. Chikungunya infected patients were identified within the COPCORD population. The aim of this study was to describe the demographics, clinical characteristics and disability of patients with clinical suspicion of chikungunya infection. To confirm chikungunya infection, ELISA IgM and IgG serology was performed. From the 6528-surveyed people of the COPCORD study, 548 where included in the study because of clinical suspicion of chikungunya virus infection. Of those, 295 were positive for IgG or IgM chikungunya serology with 151 patients fulfilling WHO clinical criteria for chikungunya infection (true positives). Most patients were > 45 years (57.7%), and females (69.7%). Patients with low income and low socio-economic strata had increased risk of chikungunya infection (p = 0.00; OR: 2.36, CI: 1.47-3.77 and p = 0.00; OR: 2.81, CI: 1.90-4.17 respectively). True positive patients were associated with symmetric arthritis (p = 0.00; OR: 22.49, CI: 12.71-39.80) of ankles (p = 0.00; OR: 16.06, CI: 7.57-34.08), hands (p = 0.00; OR: 16.12, CI: 8.25-39.79), feet (p = 0.00; OR: 16.35, CI: 7.41-36.05) and elbows (p = 0.00; OR: 14.00, CI: 3.03-64.70). Most patients developed mild to moderate disability (95.2 to 100%). Our study showed that poverty and low socioeconomic status are associated with increased risk of chikungunya infection. Also, we found two distinctive phenotypes of chikungunya infection; those with positive chikungunya serology and typical clinical symptoms (true positives) and those with positive serology without clinical symptoms (false negatives). Finally, a distinctive clinical picture presented by chikungunya infected patients was found which should be considered as the hallmark for diagnostic clinical criteria.