A urine sample will be collected to detect the presence of antimicrobials at day 0 and day 5. This procedure will ascertain pre-study antibiotic intake, as well as the patient's compliance to the health care worker's prescription or advice that antibiotics are not required, during their participation in the study. The urine samples will be collected at the sites, divided into aliquots and frozen to -80°c to be stored on site. Monthly shipments will be made to the laboratory at Mahidol Oxford Tropical Research Medicine Unit in Thailand for analysis.