Study design
We estimated the burden of diarrhoea and shigellosis in the Kaengkhoi district occurring between 1 May 2000 and 1 May 2003 using population-based, surveillance of treatment centres. The study followed a generic protocol (5), which was adapted by staff and collaborators of the Diseases of the Most Impoverished Programme. Consenting patients of all ages with diarrhoea or dysentery who presented to participating health-care providers were included in the study. Diarrhoea was defined as three or more loose bowel movements occurring during a 24-hour period; dysentery was defined as one or more loose bowel movements with visible blood; persistent diarrhoea was defined as diarrhoea lasting for more than 14 days; and fever was defined as an axillary temperature of >= 37.5 ºC. New episodes of diarrhoea were defined as those occurring after three or more days free of diarrhoea or dysentery. All consenting patients who had a history of diarrhoea lasting for three days or more were eligible to participate. For every patient presenting with diarrhoea, a case-report form, describing demographic information, medical history and the care plan, was completed and two specimens, rectal swabs or bulk stool, were obtained. One swab was placed in buffered glycerol saline (BGS) for plating and the other in phosphate-buffered saline for polymerase chain reaction (PCR) at a later time. The specimens were refrigerated and transported daily in a cool box to the central laboratory.