Abstract:
Age-period-cohort and spatial analysis were applied to dengue epidemiological
data collected at the Queen Sirikit National Institute of Child Health in Bangkok and
the Ministry of Public Health in Thailand, from 1981 to 2000.
Objective: To determine temporal trends, spatial pattern and high-risk areas of
dengue fever and dengue hemorrhagic fever in Bangkok, and in Thailand.
Methodology: The age-period-cohort model used by Clayton and Schifflers was
modified to delineate trends of dengue fever and dengue hemorrhagic fever. They
were analyzed by serotype, serology, severity and gender. Relative risk was used for
spatial analysis, to identify risk areas in Bangkok and in Thailand, and to determine
the spatial pattern of each serotype in Bangkok, Thailand.
Result: The highest relative risk was in the age group 5-9 years and the epidemic
pattern of epidemic was cyclical. The trends of dengue cases decreased both in
Bangkok and Thailand at rates of 0.1 and 0.08 per 5-year interval, respectively. The
trends of dengue hemorrhagic fever, secondary infection and female cases
significantly decreased while the trends of cases with primary infection significantly
increased (p<0.05). Huai Kwang was the high- risk area in Bangkok, and the high-risk
provinces were Tak, Loei, Krabi and Mukdahan. The spatial pattern of serotype 3
appeared to be dispersed, while serotype 4 appeared to be clustered.