The additional benefit of residual spraying and insecticide-treated curtains for dengue control over current best practice in Cuba: Evaluation of disease incidence in a cluster randomized trial in a low burden setting with intensive routine control

Abstract

BackgroundAedes control interventions are considered the cornerstone of dengue control programmes, but there is scarce evidence on their effect on disease. We set-up a cluster randomized controlled trial in Santiago de Cuba to evaluate the entomological and epidemiological effectiveness of periodical intra- and peri-domiciliary residual insecticide (deltamethrin) treatment (RIT) and long lasting insecticide treated curtains (ITC).Methodology/Principal findingsSixty three clusters (around 250 households each) were randomly allocated to two intervention (RIT and ITC) and one control arm. Routine Aedes control activities (entomological surveillance, source reduction, selective adulticiding, health education) were applied in the whole study area. The outcome measures were clinical dengue case incidence and immature Aedes infestation. Effectiveness of tools was evaluated using a generalized linear regression model with a negative binomial link function.Despite significant reduction in Aedes indices (Rate Ratio (RR) 0.54 (95%CI 0.32–0.89) in the first month after RIT, the effect faded out over time and dengue incidence was not reduced. Overall, in this setting there was no protective effect of RIT or ITC over routine in the 17months intervention period, with for house index RR of 1.16 (95%CI 0.96–1.40) and 1.25 (95%CI 1.03–1.50) and for dengue incidence RR of 1.43 (95%CI 1.08–1.90) and 0.96 (95%CI 0.72–1.28) respectively. The monthly dengue incidence rate (IR) at cluster level was best explained by epidemic periods (Incidence Rate Ratio (IRR) 5.50 (95%CI 4.14–7.31)), the IR in bordering houseblocks (IRR 1.03 (95%CI 1.02–1.04)) and the IR pre-intervention (IRR 1.02 (95%CI 1.00–1.04)).ConclusionsAdding RIT to an intensive routine Aedes control programme has a transient effect on the already moderate low entomological infestation levels, while ITC did not have any effect. For both interventions, we didn’t evidence impact on disease incidence. Further studies are needed to evaluate impact in settings with high Aedes infestation and arbovirus case load.

Effectiveness of Aedes-borne infectious disease control in Latin America and the Caribbean region: A scoping review

“…Most studies from the Latin America region were from Brazil (n = 30) [ 35 – 64 ], Mexico (n = 21) [ 90 – 109 , 120 ] and Colombia (n = 18) [ 65 – 82 ] ( Table 1 ). Most studies from the Caribbean region were from Cuba (n = 16) [ 122 – 137 ], Puerto Rico (n = 11) [ 139 – 149 ], and Trinidad (n = 2) [ 150 , 151 ] ( Table 1 ). Basic characteristics of the included studies are presented in Table 1 , and the number of publications for each year (2000–2021) is illustrated in Fig 2 .…”

“…The effectiveness of the interventions included in this review was reduced by the following factors, the spillover effect [ 76 , 108 , 138 ], small sample size [ 117 ], providing educational strategies to deploy control measures in the control group [ 68 ], parallel government campaigns [ 76 , 85 , 86 , 88 , 129 , 137 ], insecticide resistance [ 35 , 110 , 150 ] or media freedom to change or stop the distribution of information [ 71 ]. Also, most interventions were followed for a short period, which led to limited evidence on the sustainability of the employed interventions.…”

Sustainable, healthy cities: protocol of a mixed methods evaluation of a cluster randomized controlled trial for Aedes control in Brazil using a community mobilization approach

“…Furthermore, a 400 m buffer for each cluster will be used to reduce contamination, creating a 800 m minimum distance between clusters. Clusters within that boundary area will be replaced by the next cluster, from a ranked list based upon stratification criteria [58].…”

COESA - Sustainable, healthy cities: Protocol of a mixed methods evaluation of a cluster randomized controlled trial for Aedes control in Brazil using a community mobilization approach

“…Furthermore, a 400 meter buffer for each cluster will be used to reduce contamination, creating a 800 meter minimum distance between clusters. Clusters within that boundary area will be replaced by the next cluster, from a ranked list based upon stratification criteria [41].…”