Diarrhea disease is a major public health problem in developing countries. It is a communicable infected disease, which has a large number of cases and high morbidity rate. The epidemiological office the Ministry of Public Health reported that diarrhea disease in Thailand has a higher incidence rate than other communicable infected diseases (Department of Communicable Disease Control, 2000). In addition, when the epidemic pattern of diarrhea disease was studied over past 10 years, it was found that the number of cases was highest in 1999. This happened because of the drastic change in the economy and community (Vathanophas et al, 1986). A large number of people moved from the countryside to towns. As a result, the populations of the towns increased drastically and public facilities were insufficient. Water supplies were not enough to drink and use, sanitation was not good, rubbish and wastes increased, sewage and wastewater were not hygienically treated, resulting in the accumulation of germs and disease carriers (Churat, 1987; Satienchok, 1988; Satyawisis, 1990).
Epidemic patterns of diarrhea disease in Thailand had been studied by the Office of the Permanent Secretary for the public health in during 1995-1999 period. The results show that the incidence rate due to diarrhea for children was four times higher than that for adults. The Epidemiological Office also studied the incidence rate of diarrhea in 1999. It was observed that there were 981,072 cases of diarrhea disease, and the incidence rate for children was 7117.3 per 100,000 population. In 1999, there were 397 deaths from diarrhea. The disease can be found in every age group from January to December (The Office of the Permanent Secretary, 2000).
The epidemic pattern of diarrhea disease in Pattani Province, located in the south of Thailand, has been studied since 1995. The numbers of cases had increased over the 1995-1999 period. The incidence rates for each year from 1995 to 1999 were 1502.2, 1682.8, 1853.1, 1720.9, and 2783.7 per 100,000 population, respectively (Pattani Public Health Province Office Report, 1999). In 1999 the number of cases of diarrhea disease in children under 5 years old was 5,103 out of 17,265 per 100,000 population (38.56 %). It was observed that although the number of people who had diarrhea increased drastically, the mortality rate decreased. This tendency is similar to that for rural areas (Pattani Public Health Province Office Report, 1999). However the incidence rate in Pattani Province was higher than the benchmark for the control of diarrhea disease set up by the Ministry of Public Health. In developing National Public Health plan No.8 (1997-2001), a program for the control of diarrhea disease has been set up. The aim of this program is to decrease the incidence rate and mortality rate of diarrhea disease. The program states that the incidence rate of diarrhea disease in children under 5 years old should be less than 3,000 per 100,000 population, whereas that in other groups of age is less than 1,000 per 100,000 population (Ministry of Public Health, 1997). From the above information it is of interest to investigate "why diarrhea disease occurs in Pattani Province every year" and "what factors affect on acute diarrhea disease in children age under 5 years in Pattani Province".