Foodborne disease outbreaks of chemical etiology in Thailand, 1981-1987.

A study was conducted to determine the current situation of chemical foodborne outbreaks in Thailand for the period 1981-1987. Seventy-three outbreaks of chemical poisoning involving 1236 persons of whom 54 died were reported. Twenty outbreaks affecting 722 cases were caused by insecticide poisoning and methomyl was the most commonly recognized insecticide involved. Poisonous plants were responsible for 43 outbreaks with 420 cases. Mushroom poisoning was the most common entity (21 outbreaks, 211 cases), with plant seed poisoning next (9 outbreaks, 179 cases). There were 8 outbreaks following consumption of poisonous seafoods. Mussels were identified to be the vector in the outbreak of PSP. Horseshoe crabs which served as the vehicles for 4 outbreaks were also suspected to be associated with PSP. Puffer fish accounted for the remaining 3 outbreaks involving 6 cases of tetradotoxin poisoning. More complete reporting and more effort in outbreak investigations are needed for appropriate preventive and control measures.

Surveillance of food and waterborne diseases in Thailand, 1979-1984.

National surveillance of foodborne diseases in Thailand has revealed an increasing incidence of from 29/100,000 population in 1979 to 74/100,000 in 1984. A total of 158,482 cases and 241 deaths were reported during this 6 year period. In each year, foodborne diseases occurred regularly in April-June. The highest mean annual reported rates were from the North-eastern region, followed by the Central region and the Northern region. Because of inadequate investigations, only 7% (10,567) of the total cases had known specific aetiology. Of these 10,567 cases, the majority (7788, 73%) were caused by micro-organisms which included bacteria (46%), parasites (12%), and viruses (15%), the remaining (2779, 27%) were caused by poisonous plants (19%), animals (1%), and chemicals (7%). In recent years surveillance has increasingly served as a means to control the outbreak. However, due to many limitations, the surveillance data presented here probably do not represent an accurate picture of the whole problem. Two very important factors identified are under-reporting and inadequate case and outbreak investigations.

Surveillance of diarrhoeal diseases in Thailand.

PIP: 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).^ieng