Outbreak of Chikungunya virus in the north Caribbean area of Colombia: clinical presentation and phylogenetic analysis.

INTRODUCTION The Caribbean area of Colombia has been severely affected by a Chikungunya virus (CHIKV) outbreak since 2014. METHODOLOGY The study was carried out on 100 patients during a fever outbreak from August to September 2014 in two small rural villages in the northern Caribbean area of Colombia. The molecular assays performed by reverse transcription polymerase chain reaction (RT-PCR) on acute patient sera were collected within one to five days of the appearance of symptoms. Sequence analyses were carried out based on phylogenetic analyses of genes NS1 and E2. For serological assays, 49 (49%) patients at ≥ 6 days of disease onset were tested with NovaLisa Chikungunya IgG/IgM µ-capture enzyme-linked immunosorbent assay (ELISA). RESULTS The main signs or symptoms associated with Chikungunya infection were arthralgia of the lower limbs (96%), fever (91%), arthralgia of the upper limbs (85%), rash (64%), and headache (57%). Ninety-four percent (46/49) of patients were positive for either IgM or IgG; the remaining three (6%) patients were seronegative. Viral loads were detected in 25 patients. Based on phylogenetic analysis of NS1 and E2, the characterization of the Colombian CHIKV indicated that it was a strain closely related to the British Virgin Islands strain and to the Asian genotype. CONCLUSIONS This study shows the phylogenetic and clinical description of CHIKV in Colombia. The main symptoms shown were: arthralgia, fever, and rash. CHIKV sequences detected in Colombian patients were within the Asian genotype and closely related to the British Virgin Islands strain.