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Table 1 Sensitivity analysis on the parametric shape of the function representing the time-dependent transmission rate

From: Infectiousness of pigs infected by the Porcine Reproductive and Respiratory Syndrome virus (PRRSV) is time-dependent

Function shape

Latent period (days)

Parameters (IC 95%)

Mean generation time Tg(IC)

Goodness of fit testson observed data

K

θ

R 0

χ2P-value

Coefficient of determination (R2)

Gamma

0

10.0 (−3.4, 23.4)

1.5 (1.1, 1.8)

2.4 (1.8, 3.0)

14.7 (ND, 32.3)

0.870

0.950

1

8.7 (−0.9, 18.4)

1.6 (1.2, 1.9)

2.4 (1.8, 3.0)

14.7 (ND, 33.1)

0.878

0.953

2

7.6 (0.8, 14.3)

1.7 (1.3, 2.1)

2.4 (1.8, 3.1)

14.7 (3.0, 30.7)

0.888

0.956

Lognormal

0

2.63 (2.63, 2.64)

0.31 (0.31, 0.32)

2.5 (1.8, 3.2)

14.6 (14.5, 14.7)

0.975

0.968

1

2.5 (2.5, 2.6)

0.34 (0.33, 0.34)

2.6 (1.8, 3.3)

14.5 (14.4, 14.6)

0.979

0.971

2

2.46 (2.45, 2.47)

0.36 (0.36, 0.37)

2.6 (1.8, 3.4)

14.5 (14.4, 14.6)

0.983

0.974

Weibull

0

16.4 (14.2, 18.6)

2.9 (2.5, 3.3)

2.2 (1.8, 2.6)

14.6 (12.6, 16.7)

0.629

0.874

1

15.4 (13.3, 17.5)

2.8 (2.4, 3.1)

2.2 (1.8, 2.6)

14.7 (12.8, 16.7)

0.637

0.880

 

2

14.4 (12.4, 16.4)

2.6 (2.4, 2.9)

2.2 (1.8, 2.6)

14.8 (13.0, 16.6)

0.647

0.887

  1. Estimates and 95% confidence intervals (CIs) of the parameters of the infectious potential function distribution, estimated basic reproduction ratio R0, mean generation time Tg and goodness of fit tests on observed data according to the assumed duration of the latent period.
  2. (β(τ)), parametric function of the infectious potential; k, θ, parameters of β(t); R0, basic reproduction ratio defined as the average number of secondary infections occurring from a single infected animal during its infectious period in a totally susceptible population; Tg, mean generation time defined as the sum of the mean latent period and the mean infectious period; R2, coefficient of determination; ND, not defined).