Table 6. Parameter-estimates of generalized linear models predicting viral excretion of ferrets inoculated with different influenza viruses.

Virus	Predictor	B coefficient	Standard error	Wald χ2	P
H3N2	Intercept	1.605	0.34	22.3	<0.0001
	Viral production in URRT	0.383	0.08	22.3	<0.0001
pH1N1	Intercept	0.325	0.25	1.7	0.187
	Viral production in URRT	0.508	0.04	201.7	<0.0001
H5N1	Intercept	27.830	10.06	7.6	0.006
	Viral production in DRRT	−2.827	1.19	5.6	0.018
	Damage in DRRT	−3.887	1.72	5.1	0.024
	Viral production in DRRT×Damage in DRRT	0.456	0.20	5.0	0.025
	Damage in URRT	−0.687	0.20	11.8	0.001
	Damage in URRT×Viral production in URRT	0.046	0.01	9.2	0.002
	Damage in URRT×Viral production in DRRT	0.049	0.02	4.6	0.031

URRT: upper regions of the respiratory tract (nose and trachea); DRRT: deeper regions of the respiratory tract (bronchi, bronchioles and alveoli).