Surveillance of diarrhoeal diseases in Thailand.

Abstract

To provide information for prevention and control activities at national and local levels, Thailand's Ministry of Public health has monitored trends for diarrheal diseases since 1970. Data for the 1978-83 period obtained from the national epidemiological surveillance system are reported. The data were collected largely through a passive surveillance network in each province of Thailand. After preliminary analysis and tabulation at the local level, data were sent to the Ministry of Public Health for further analysis. Details on each case of diarrheal disease included the age, sex, place of residence, date of onset, and place of treatment. 5 categories of diarrheal diseases were distinguished: cholera, enteric fever, food poisoning, dysentery, and acute diarrhea. The causative agents of diarrheal diseases generally were isolated and identified in provincial hospital laboratories or at a government regional laboratory. During the 1978-83 period, 1,979,118 cases of diarrheal diseases were reported to the Thai Ministry of Public Health through the national surveillance system. The annual number of cases increased from 175,411 in 1978 to 537,972 in 1983, and this is reflected in an increase in the annual incidence from approximately 400/100,000 population in 1978 to over 1000/100,000 population in 1983. The average annual incidence of diarrheal diseases reported over this period was 694/100,000 or approximately 330,000 cases per annum. The number of cases of all categories of diarrheal disease increased, except cholera, which fluctuated from year to year. Acute diarrhea exhibited the highest average annual incidence (537/100,000), followed by that of dysentery (85), food poisoning (43), and enteric fever (25). Cholera had the lowest incidence (4/100,000). Over the 6-year study period, the majority of cases reported were acute diarrhea (77.4%), followed by dysentery (12.2%), food poisoning (6.3%), and enteric fever (3.5%). Cholera accounted for 0.6% of cases. A total of 3300 deaths from diarrheal diseases were reported over the study period. Deaths in each disease category, except cholera, decreased, and the annual number of deaths declined from 911 in 1978 to 370 in 1983. Acute diarrhea was the most common category leading to death. For acute diarrhea, the highest age-specific mortality rate was among children aged 0-4 years. Age-specific mortality rates for the remaining disease categories were much lower. The highest mean incidence rate for reported cases of acute diarrhea occurred in the central region of Thailand (608/100,000).