Fig 1.
The shaded area, site Z-7L of 12 ha, demarcated for wide area Bti spray treatment.
A low lying riverine site, 500 meters from Rajang River. In Zone 5 and in Zone 14 the wide area Bti spray treatments were not conducted.
Table 1.
Year 2015, the mean number ± S.E. of in-use containers surveyed per household in epidemiology weeks (EW) 19–41 in Z-5, control site, and in Z-7L, Bti treated site.
Fig 2.
For 2015 epidemiology weeks 19–41, Aedes index (AI, %) and Larval Density (LD) from Z-5, the control site, and from Z-7L, the Bti treated site.
Fig 3.
For 2015 epidemiology weeks 19–41, pupa density (PD) from Z-5, the control site, and from Z-7L, the Bti treated site.
Table 2.
For 2015, the mean Aedes index (AI) ± SE per surveillance conducted in epidemiology weeks (EW) 19–39 in Z-5, control site and in Z-7L, Bti treated site.
Impact of larviciding with Bti on Aedes index was determined at p = 0.05.
Table 3.
For 2015, the mean larval density (LD) ± SE per surveillance conducted in epidemiology weeks (EW) 19–39 in Z-5, control site and in Z-7L, Bti treated site.
Impact of larviciding with Bti on LD was determined at p = 0.05.
Fig 4.
For 2015, the regression relationship between larval density (LD) and Aedes index (AI) during the 23 weeks of entomological surveillance conducted in Z-7L, the Bti treated site.
There was a strong positive correlation (R2 = 0.92) between LD and AI.
Fig 5.
For 2015, the regression relationship between larval density (LD) and Aedes index (AI) during the 23 weeks of entomological surveillance conducted in Z-5, the control site.
There was a moderate positive correlation (R2 = 0.48) between LD and AI.
Table 4.
Correlation coefficient between Aedes index (AI) and larval density (LD) within Z-5, control site and in Z-7L, Bti treated site.
Table 5.
For 2015, the mean ovitrap index ± SE per surveillance conducted in epidemiology weeks (EW) 19–41 in Z-5, control site, and in Z-7L, Bti treated site.
Impact of larviciding with Bti on OI was determined at p = 0.05.
Fig 6.
For 2014 epidemiology weeks 1–53, the incidence rate (IR) per 100,000 population in 3 sites: Z-5, Z-7L and Z-14.
In all 3 sites routine operational vector control activities were conducted, excluding larviciding with Bti.
Fig 7.
For 2015 epidemiology weeks 1–52, the incidence rate (IR) per 100,000 population in 3 sites: Z-5, Z-7L and Z-14.
In all 3 sites routine operational vector control activities were conducted. However, the direct Bti application into containers and wide area Bti spray treatment were integrated in the routine control activities in site Z-7L on weekly interval from EW 24–27 () and fornightly interval from EW 28–35 (
).
Table 6.
For 2015–2016, the combined incidence rate (IR) per 100,000 population during the pre Bti treatment impact and Bti treatment impact phases.
In 2015, the Bti treatment was implemented in Z-7L in EW 24 and in 2016 in EW 27. Impact on the dengue transmission was observed 4 weeks after the Bti treatment initiation.
Fig 8.
For 2016 epidemiology weeks (EW) 1–52, incidence rate (IR) per 100,000 population in 3 sites: Z-5, Z-7L and Z-14.
In all 3 sites routine operational vector control activities were conducted, excluding wide area Bti spray treatment. However, in site Z-7L as from EW 27 until the end of the year () the wide area Bti spray application on fortnight intervals was integrated into the routine operational vector control activities.