Interaction between background force of infection, seasonality, timing of control, and the magnitude of the divorce effect.

(a) Increasing seasonality (β₁ = .1 in contrast to β₁ = .02 in S22 Fig) increases the variation in the divorce effect seen at differing background force of infections. (b) Likewise, the timing of the start of the control (days 0, 73, 146, 219, 292) has a significant effect on the magnitude of the divorce effect seen at a particular background force of infection.

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