Table 1.

 Summary of acute clinical signs observed for each pig in the naïve transmission chain

Pig	Pair	Clinical sign	D0	D1	D2	D3	D4
115	1	Depression			+
		Nasal discharge			+	+
		Ocular discharge
		Dyspnoea			+
		Cough
113	1	Depression			+
		Nasal discharge
		Ocular discharge			+	+
		Dyspnoea
		Cough			+
104	2	Depression			+
		Nasal discharge		+	+	+	++
		Ocular discharge			+	+	+
		Dyspnoea				+
		Cough			+	+	+
116	2	Depression			+	+	+
		Nasal discharge		+	+	+	+
		Ocular discharge
		Dyspnoea			+		+
		Cough				+	+
109	3	Depression
		Nasal discharge			+	+	+
		Ocular discharge
		Dyspnoea
		Cough
111	3	Depression
		Nasal discharge		+	++	+	++
		Ocular discharge			+
		Dyspnoea
		Cough				+	+
108	4	Depression				+	+
		Nasal discharge		+	+	+	+
		Ocular discharge
		Dyspnoea
		Cough
105	4	Depression			+	+	+
		Nasal discharge		+	+	+	+
		Ocular discharge
		Dyspnoea
		Cough
112	5	Depression				+	+
		Nasal discharge		+	+		+
		Ocular discharge		+	+		+
		Dyspnoea
		Cough
106	5	Depression					+
		Nasal discharge				+
		Ocular discharge		+	+		+
		Dyspnoea		+	+		+
		Cough
110	6	Depression				+	+
		Nasal discharge		++	+		+
		Ocular discharge
		Dyspnoea
		Cough
114	6	Depression				+	+
		Nasal discharge		+	+		+
		Ocular discharge
		Dyspnoea
		Cough				+	+
107	7	Depression			+	+
		Nasal discharge		+	++	+
		Ocular discharge			+
		Dyspnoea
		Cough				+
103	7	Depression			+	+
		Nasal discharge		+	++
		Ocular discharge
		Dyspnoea
		Cough				+

+, sign observed; ++, mucopurulent discharge; blank cell, sign not observed; shaded cell, no sample collected (animal euthanased).