Endpoints: diagnostic sensitivity of CHIKV RT-PCR on urine samples in patients with a confirmed CHIKV infection, comparison of analytical sensitivity (based on Ct-values) with RT-PCR on serum, positivity rates of RT-PCR urine samples over time Ethical issues: Informed consent will be obtained from study participants. Demographic, geographic, clinical and laboratory data will be obtained; the data are de-identified and stored in an encoded database (code known to the principal investigators). Ethical approval through the ITM/ University Hospital Antwerp (UZA) Ethics Committee (EC) and the EC in Aruba.