We define two variables T p and F for ease of reporting and comparing results. With per-contact transmission rate t and detection rate a, the transmission probability per link over the period before the detection of the infectious node is given by T p Zt/(tCa) (Keeling & Grenfell 2000) . Constant hkiT p provides a constant number of secondary infections caused by the introduction of infection at a node when the remainder of the network is susceptible (Keeling & Grenfell 2000) , at the cost of having different epidemic dynamics as hki varies ). In a parallel manner, with per-contact-tracing rate 4 and removal rate of triggering nodes d, the tracing probability per traceable link over the whole tracing triggering period is given by FZ4/(4Cd).