Longitudinal field studies reveal early infection and persistence of influenza A virus in piglets despite the presence of maternally derived antibodies

Table 5 Mean coughing index (CI) of virus-positive and -negative animals

Mean CI	Week 1	Week 3	Week 5	Total
Herd 1
Virus positive	0.209	0.381	0.032	0.263
SD	0.21	0.28	0.04	0.26
Virus negative	0.026	0.223	0.05	0.089
SD	0.03	0.19	0.03	0.13
P-value	0.007	0.21	0.44	0.006
Herd 2
Virus positive	0.042	0.348	0.109	0.168
SD	0.05	0.16	0.08	0.16
Virus negative	0.109	0.56	0.088	0.234
SD	0.12	0.53	0.05	0.36
P-value	0.40	0.41	0.48	0.48
Herd 3
Virus positive	0.065	0.186	0.083	0.108
SD	0.04	0.09	0.03	0.08
Virus negative	0.090	0.239	0.106	0.166
SD	0.07	0.26	0.05	0.2
P-value	0.40	0.64	0.45	0.26

The results were considered significant at P < 0.05. “SD” is the standard deviation.

ISSN: 1297-9716