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Table 6 The average number of Anopheles gambiae s.l. collected per CDC LT collection-night during the cluster-randomized trial, by village IRS status

From: Reduced exposure to malaria vectors following indoor residual spraying of pirimiphos-methyl in a high-burden district of rural Mozambique with high ownership of long-lasting insecticidal nets: entomological surveillance results from a cluster-randomized trial

Month

Average number of mosquitoes collected per trap-night (95% CI)

IRRa

pb

No-IRS

IRS

Sep-16

0.01 (0.00–0.04)

0.02 (0.00–0.04)

0.33

< 0.001

Oct-16

0.01 (0.00–0.02)

0.07 (0.02–0.12)

2.00

< 0.001

Nov-16

0.01 (0.00–0.02)

0.00 (0.00–0.00)

1.00

NR

Dec-16

0.11 (0.04–0.19)

0.23 (0.11–0.37)

1.60

0.247

Jan-17

–

–

–

–

Feb-17

–

–

–

–

Mar-17

0.62 (0.28–1.05)

0.21 (0.09–0.35)

0.97

0.953

Apr-17

1.30 (0.86–1.83)

0.70 (0.46–0.97)

0.53

0.083

May-17

0.21 (0.05–0.40)

0.25 (0.11–0.40)

0.65

0.241

Jun-17

0.05 (0.00–0.10)

0.01 (0.00–0.03)

1.00

NR

Jul-17

0.02 (0.00–0.04)

0.00 (0.00–0.00)

1.00

NR

Aug-17

0.01 (0.00–0.03)

0.01 (0.00–0.04)

2.00

< 0.001

Sep-17

0.01 (0.00–0.03)

0.00 (0.00–0.00)

1.00

NR

Oct-17

0.00 (0.00–0.00)

0.02 (0.00–0.05)

1.00

NR

Nov-17

0.01 (0.00–0.03)

0.01 (0.00–0.02)

1.00

NR

Dec-17

0.07 (0.01–0.14)

0.01 (0.00–0.04)

0.75

0.048

Jan-18

0.67 (0.38–1.00)

0.12 (0.04–0.22)

0.52

0.015

Feb-18

0.10 (0.01–0.19)

0.03 (0.00–0.06)

0.23

< 0.001

Mar-18

0.40 (0.20–0.63)

0.08 (0.01–0.15)

0.97

0.931

Apr-18

–

–

–

–

May-18

0.09 (0.02–0.18)

0.02 (0.00–0.04)

0.37

< 0.001

Jun-18

0.06 (0.01–0.11)

0.03 (0.00–0.06)

1.33

0.162

Jul-18

0.03 (0.00–0.07)

0.02 (0.00–0.05)

0.75

0.501

Aug-18

0.00 (0.00–0.00)

0.04 (0.00–0.07)

1.00

NR

Sep-18

0.00 (0.00–0.00)

0.01 (0.00–0.02)

1.00

NR

Oct-18

0.17 (0.05–0.29)

0.09 (0.02–0.17)

0.76

0.499

Overallc

0.15 (0.13–0.18)

0.08 (0.07–0.10)

0.66

0.019

  1. The geometric mean number (with 95% CI) of mosquitoes by month are presented. Months highlighted in italics show the duration of the IRS campaigns
  2. CDC LT US Centers for Disease Control light trap, IRR incidence rate ratio, IRS indoor residual spraying
  3. Incidence ratio from the zero-inflated negative binomial regression analysis, describing the rate at which mosquitoes were collected in IRS villages relative to no-IRS villages. An IRR = 1 indicates no difference across study arms
  4. bThe probability that the true IRR = 1; zero-inflated negative binomial regression
  5. cOverall averages from the duration of the study after the first IRS campaign, December 2016–October 2018