Table 1.

Parameters used in individual based simulation of on-farm epidemiology of MDV. Personal communication refers to Nick Sparks (NS). $Z(k,v,j)$ is the quantity of virus in the atmosphere (VCN) on day k for an outbreak of virulence $v$ in a cohort with vaccination status j (Fig. 1).

Parameter	Symbol	Value/s	Reference
Daily dust production per bird (mg)	d(t, Tc)	368 exp(− P(Tc)/t1.64) + 10.8	Atkins et al. (2013)
Daily transmission probability per bird per VCN/m3
Unvaccinated	αsham	4.93 × 10−8	From data in Atkins et al. (2011)
HVT	αHVT	8.26 × 10−10	From data in Atkins et al. (2011)
Total flock mortality (%)	μtotal	3.6–6.8	Sheppard (2004)
Daily non-MDV death probability	μ	$1-\sqrt[T_c]{1-{\mu }_{\mathrm{total}}}$	Atkins et al. (2013)
Age at introduction (days)	e	2	Sheppard (2004)
Height of barn (m)	h	2.5	NS pers. comm
Finishing weight (kg)	$w$	2.5	NS pers. comm
Maximum dust threshold (mg/m3)	E	7.15	Takai et al. (1998)
Initial dust (mg)	D0	0–560	Unknown
Vaccination status	j	Sham, HVT	Bublot and Sharma (2004)
Probability MDV infection on day k	p	${\alpha }_j\frac{Z(k,v,j)}{V(S_0,s_d)}$	Atkins et al. (2013)
Growth scaling constant	P(Tc)	$-T_c^{1.64}ln\left(\frac{d(45,45)-10.8}{368}\right)$	Atkins et al. (2013)
Weibull shape parameter	r	4.18 (3.38–4.99)	Atkins et al. (2011)
Stocking density (kg/m2)	sd	5, 20, 35	NS pers. comm
Initial cohort size (birds)	S0	500, 5000, 30000	NS pers. comm
Cohort duration (days)	Tc	30, 60	Sheppard (2004)
Dust reduction at end of cohort (%)	ϵ	0–100	Unknown
Virus virulence score (%)	$v$	16.5, 36, 46	Atkins et al. (2011)
Transformed virulence score	$v_T$	$arcsin\sqrt{0.01v}$	Atkins et al. (2011)
Barn volume (m3)	V(S0, sd)	S0wh/sd	Atkins et al. (2013)
Virus extinction threshold (VCN/m3)	ze	10−9, 10−5	Unknown