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Table 1 Parameters for the global risk model. Subscripts 1 and 2 referred to Ae. aegypti and Ae. albopictus respectively. Unless otherwise stated, parameter values were calculated following Caminade et al. [13]

From: Mapping the cryptic spread of the 2015–2016 global Zika virus epidemic

Symbol Description Calculation
h1, h2 Biting rates
(per day)#
h1 = 0.67, [41]
h2 = h1/2.
ϕ1, ϕ2 Vector preferences ϕ1 = 1,
ϕ2 = ϕ1/2.
\( {\uptau}_1^{V\to H} \), \( {\uptau}_2^{V\to H} \) Vector-to-host transmission probability \( {\uptau}_1^{V\to H}=0.5 \),
\( {\uptau}_2^{V\to H}={\uptau}_1^{V\to H}. \)
\( {\uptau}_1^{H\to V} \), \( {\uptau}_2^{H\to V} \) Host-to-vector transmission probability \( {\uptau}_1^{H\to V}=0.1 \),
\( {\uptau}_2^{H\to V}=0.33{\uptau}_1^{H\to V}. \)
μ1, μ2 Mortality rates
(per day)
\( {\mu}_1=\frac{1}{1.22+\mathit{\exp}\left(-3.05+0.72T\right)}+0.196,\left(T<22{}^{\circ}C\right) \)
\( {\mu}_1=\frac{1}{1.14+\mathit{\exp}\left(51.4-1.3T\right)}+0.196,\left(T\ge 22{}^{\circ}C\right) \)
\( {\mu}_2=\frac{1}{1.1+\mathit{\exp}\left(-4.04+0.576T\right)}+0.11883,\left(T<15{}^{\circ}C\right) \)
μ2 = 0.000339T2 − 0.0189T + 0.336, (15 ° C ≤ T < 26.3 ° C)
\( {\mu}_2=\frac{1}{1.065+\mathit{\exp}\left(32.2-0.92T\right)}+0.073079.\left(T\ge 26.3{}^{\circ}C\right) \)
ν1,  ν2 Extrinsic incubation rates (per day) \( {\nu}_1=\frac{1}{4+\mathit{\exp}\left(5.15-0.123\ T\right)}, \)
ν2 = ν1/1.03.
m1, m2 Vector-to-host ratios Assumed to be proportional to the vector suitability values.
The scaling factor was re-calibrated using the  R0 estimate produced by Zhang et al. [11].
r Human recovery rate
(per day)
r = 1/7.
  1. #Given the relatively minor contribution of the biting rates’ temperature-dependence to the variation in R0 [42], here we treated the biting rates as constant, and the uncertainties in \( \frac{h^2{\phi}^2{\tau}^{V\to H}{\tau}^{H\to V}}{r} \) were absorbed by re-calibrating the scaling factor that converted vector suitability values to vector-to-host ratios