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Table 2 Generalized linear model testing the effects of sampling year (1993–2012), ecological zone (zones 1 and 2) and their interaction on bioassay mortality for (a) DDT, (b) permethrin, (c) deltamethrin, (d) carbamates (bendiocarb & propoxur), (e) organophosphates (fenitrothion & malathion)

From: Long-term trends in Anopheles gambiae insecticide resistance in Côte d’Ivoire

(a) DDT

Wald χ2

d.f.

P-value

Intercept

337.471

1

0.000

Year (covariate)

337.866

1

0.000

Ecological zone

68.178

1

0.000

Year × ecological zone

68.062

1

0.000

(b) deltamethrin

Wald χ 2

d.f.

P-value

Intercept

56.854

1

0.000

Year (covariate)

55.615

1

0.000

Ecological zone

4.833

1

0.028

Year × ecological zone

4.926

1

0.026

(c) permethrin

Wald χ 2

d.f.

P-value

Intercept

6.848

1

0.009

Year (covariate)

7.001

1

0.008

Insecticide concentration

63.232

1

0.000

Ecological zone

33.974

1

0.000

Year × ecological zone

33.889

1

0.000

(d) carbamate

Wald χ 2

d.f.

P-value

Intercept

1.205

1

0.272

Year (covariate)

1.193

1

0.275

Insecticide type

5.922

1

0.015

Ecological zone

72.697

1

0.000

Year × ecological zone

72.311

1

0.000

(e) organophosphate

Wald χ 2

d.f.

P-value

Intercept

1.517

1

0.218

Year (covariate)

1.693

1

0.193

Ecological zone

59.664

1

0.000

Year × ecological zone

59.063

1

0.000

  1. In (b) and (c) two (similar) insecticide concentrations were present in the data so this term was also included as an effect in each model but not in interactions owing to insufficient variance.