The pattern of diarrhea in children in Khon Kaen, northeastern Thailand: I. The incidence and seasonal variation of diarrhea.

The incidence, seasonal variation and risk factors of diarrhea in children in Thailand are not well defined. The objective of this study is to identify the incidence and seasonal variation of diarrhea in a rural community. A cohort of 481 children under five years of age from 14 villages in rural northeastern Thailand was followed for 1 year, from May 1988 to April 1989. The data were collected daily by 5 participant observers who resided in the villages during the study period. During the 25,012 person weeks of surveillance, 384 episodes of diarrhea occurred; 279 episodes (72.7%) were watery diarrhea and 105 episodes (27.3%) were dysentery-like diarrhea. The incidence of diarrhea was 2.1, 1.76, 0.96 and 0.45 episodes per child per year for children aged 0-6 months, 7-12 months, 1 year and above 2 years, respectively. Males were affected as frequently as females. The average duration of illness was 4.9, 2.1, 1.5 and 0.5 days per child per year for children aged under 1 year, 1-2 years, 2-3 years and more than 3 years old, respectively. Both dysentery and watery diarrhea rates peaked for children of all ages from May to July, during the early rainy season. A second peak of watery diarrhea in the winter from November to January and was seen primarily in children less than 2 years old. The monthly incidence of diarrhea was associated with rainfall, ambient temperature and occupational behavior of people in each season.