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Table 3 Adjusted effects of mosquito-disseminated pyriproxyfen on species-specific adult-mosquito catches (Aedes aegypti and Culex quinquefasciatus): top-ranking (smallest-BIC) generalized linear mixed models

From: Measuring mosquito control: adult-mosquito catches vs egg-trap data as endpoints of a cluster-randomized controlled trial of mosquito-disseminated pyriproxyfen

Term Estimate SE 95% CI
Lower Upper
Aedes aegypti
Fixed effects
Intercept (CC, BP)a − 0.618 0.354 − 1.312 0.077
Intervention period (IP)b − 0.535 0.367 − 1.253 0.184
Intervention cluster (IC) 0.508 0.319 − 0.118 1.134
IP × ICc − 0.916 0.295 − 1.493 − 0.338
Rainfalld 0.829 0.146 0.543 1.116
Random effects SD
Dwelling ID 0.766 0.585 1.001
Month 0.455 0.275 0.755
Culex quinquefasciatus
Fixed effects
Intercept (CC, BP)a 0.430 0.396 − 0.346 1.205
Intervention period (IP)b 0.080 0.382 − 0.669 0.828
Intervention cluster (IC) − 1.172 0.380 − 1.917 − 0.427
IP × ICc − 0.807 0.291 − 1.378 − 0.237
Temperatured 0.707 0.156 0.400 1.012
Random effects SD
Dwelling ID 1.091 0.868 1.370
Month 0.502 0.328 0.767
  1. aThe intercept estimates the (log-scale) expected mean number of mosquitoes caught per 10 minutes aspiration in the CC, in the typical dwelling and at typical temperatures, during the BP; the other fixed-effect slope coefficients estimate changes in this expectation associated with period, cluster, intervention, and rainfall or temperature effects
  2. bNote that both models estimate non-significant changes in (log) mean mosquito-catch as the CC entered the IP (but received no intervention), with the 95% confidence intervals including zero
  3. cThe ‘IP × IC’ interaction coefficients estimate the (log) change in expected mean mosquito-catch that can be attributed to the intervention (deployment of 150 pyriproxyfen dissemination stations over 13 months (the IP) in the IC). The Aedes model estimates an e− 0.916 = 0.400 incidence rate ratio, indicating that the intervention resulted in a 100 − 40.0 = 60.0% reduction (95% CI: 28.7–77.5%) of the expected mean Aedes-catch; the Culex model estimates an e− 0.807 = 0.446 incidence rate ratio, or a 55.4% reduction (95% CI: 21.1–74.8%) of the expected mean Culex catch
  4. dSpecified as the (standardized) total rainfall in the month before sampling (‘rain_m’) for the Aedes model and as the mean of minimum daily temperatures in the month before sampling (‘tmin_m’) for the Culex model; the original variables had the following means (SDs): ‘rain_m’, 131.6 mm (111.3); ‘tmin_m’, 17.39°C (1.73). Given our focus on estimating adjusted intervention effects, we considered weather covariates as confounders; those in the table yielded better-performing models, as measured by BIC scores, than other measures of temperature and rainfall
  5. Abbreviations: BIC, Bayesian information criterion; SE, standard error; 95% CI, 95% confidence interval (lower/upper limits); CC, control cluster; BP, baseline period; IP, intervention period; IC, intervention cluster; SD, standard deviation; ID, identity of each sampling dwelling