3. Vector density: IRS versus no intervention.
Trial ID | Unit of randomization | Insecticide | Main vector | Measure (method) | Pre‐intervention | Post‐intervention | Effect measure (95% CI) or P value | ||
IRS | Control | IRS | Control | ||||||
Chowdhury 2011 BGD | Cluster of 50 houses | Deltamethrin (20 mg/m²) | P. argentipes | Total sandflies (monthly collections from 40 houses using light traps). |
633 (October 2006) | 683 (October 2006) | 8 (January 2007) 285 (March 2007) |
54 (January 2007) 1219 (March 2007) |
RR 0.38 (0.10 to 1.50) (Jan 2007) RR 0.28 (0.19 to 0.42) (Mar 2007) The benefit with IRS was no longer present at 12 months |
Joshi 2009 ASIA | Hamlets or neighbourhoods | Deltamethrin ‐ BGD
(20 mg/m²) DDT ‐ IND (1 g/m²) Alpha‐cypermethrin ‐ NPL (0.025 g/m²) |
P. argentipes | Mean number of sandflies per house per night (light traps) | 12.32 (date not stated) |
9.41 (Date not stated) |
6.14 (5 months post intervention) |
12.15 (5 months post intervention) |
Pre‐intervention P = 0.184 Post‐intervention P = 0.035 |
Kelly 1997 BRA | Chicken sheds | Lambdacyhalothrin (20 mg/m²) |
Lu.longipalpis | Geometric mean sandflies (light traps) | 1132.3* (October 1993) |
404.6* (October 1993) |
Not reported | Not reported | Pre‐intervention P < 0.001 The trial authors state "the abundance of Lu. longipalpis in sprayed sheds fell to approximately 10% of that expected, and remained so up to week 29". |
Feliciangeli 2003 VEN | House | Lambdacyhalothrin (25 mg/m²) | Lu. ovallesi | Total sandflies over 79 days post‐intervention (daily catches using light traps) |
Not reported | Not reported | 2517 | 2472 | The trial authors state "The estimated catches of males, females, and fed females were significantly lower in sprayed houses immediately after spraying". However, over time the density in the control group also decreased ‐ probably due to seasonality |
Proportion of blood fed females | Not reported | Not reported | 0.8% | 5.8% |
Abbreviations: VEN = Venezuela; BRA = Brazil; BGD = Bangladesh; IRS = indoor residual spraying; RR = risk ratio).