The effectiveness of Aedes aegypti larval control and DHF incidence in Pre-epidemic period

Abstract

The objective of this study is to identify the correlation between Aedes aegypti larval control and DHF incidence in Pre - epidemic period.

Methodology: 2 variables as mentioned below. 1) The larval indices were collected from the systematic randomized larval survey which was conducted by 12 regional offices for Disease prevention and Control and Bangkok Metropolitan Administration in 72 provinces (4,139 communities) during March 2006 to April 2006. 2) The Dengue incidence was collected from 72 provinces. The statistical tools used in the study were chi square and correlation coefficient.

Result: The Dengue incidence rate showed the moderate degree of correlation with the percentage over 80% of the community larval survey HI < 10 (r = -0.4063 and alpha = 0.05 degree of freedom = 22)

Conclusion: the dengue incidence rate showed the moderate degree correlation with the percentage of the communities that abundant larval survey HI≤10 more than 80% by statistics significant that the correlation coefficient (r) = -0.4063 ( = 0.05 d.f. = 22). The negative relation value was corresponded to the dengue epidemic hypothesis, that a province with low percentage of standard larval control communities (HI < 10 less than 80%) appear high tendency of disease occurrence. Altogether various statistics tools backup the assumption that provinces with rather poor larvae control have rather more incidence rate than those provinces have Aedes aegypti larvae low prevalence especially during first quarter. These results support the early prevention in the interval of golden period during dry season before Dengue hyper endemic in rainy season.