Abstract:
Cambodia has one of the highest dengue infection rates in Southeast Asia. Here we report
quantitative entomological results of a large-scale cluster-randomised trial assessing the
impact on vector populations of a package of vector control interventions including larvivorous guppy fish in household water containers, mosquito trapping with gravid-ovitraps, solid
waste management, breeding-container coverage through community education and
engagement for behavioural change, particularly through the participation of school children. These activities resulted in major reductions in Container Index, House Index, Breteau
Index, Pupal Index and Adult Index (all p-values 0.002 or lower) in the Intervention Arm compared with the Control Arm in a series of household surveys conducted over a follow-up
period of more than one year, although the project was not able to measure the longer-term
sustainability of the interventions. Despite comparative reductions in Adult Index between
the study arms, the Adult Index was higher in the Intervention Arm in the final household survey than in the first household survey. This package of biophysical and community engagement interventions was highly effective in reducing entomological indices for dengue
compared with the control group, but caution is required in extrapolating the reduction in
household Adult Index to a reduction in the overall population of adult Aedes mosquitoes,
and in interpreting the relationship between a reduction in entomological indices and a
reduction in the number of dengue cases. The package of interventions should be trialled in
other locations.
