Spatial mapping of temporal risk characteristic of dengue cases in Subang Jaya

Dengue has become the most widespread vector borne viral diseases of human with the rough estimate of between 60 and 100 million cases of dengue fever worldwide annually. This study proposed a new set of parameters which defined dengue occurrence at an area according to its time characteristics. The objectives of this study were to measure the temporally defined risk indices, to map the measured temporal risk indices and to statistically prove the relationship between each temporal risk indices. Measurement of the three temporal risk indices found that there were areas with significant high value for each of the temporal indices. This suggested that areas within Subang Jaya Municipality had different temporal characteristics for dengue occurrence. The value of frequency index was quite low which was below the minimum of 1. 1 indicates that dengue will occur every week throughout the year. The mean value of duration index was 1.66 which pointed out that the mean duration of an epidemic wave was about 2 weeks. 5.41 was the mean value for intensity index and it signified that during an epidemic wave, about 5 to 6 people in a population of 1000 would be infected by dengue fever. Mapping, which is a spatial analysis method, is utilized for the visual analysis of the three temporal indices. It was found that most areas had high frequency indices. Visual analysis of the duration index showed that there was a distribution pattern where areas with a history of high duration per wave would experience it in the future. There is no significant distribution pattern for intensity index as the high value tended to stay at the same locality throughout the years. Three types of relationship, frequency-duration relation, frequency-intensity relation and duration-intensity relation were identified. The correlation coefficient for all the three types of relationship was above 0.7. The value indicated that there was a strong correlation between each temporal risk indices. As a recommendation, the temporal risk indices can be utilized by public health officials to characterize dengue rather than relying on the traditional case incidence data.