Table 3.

Virological findings in patients with avian influenza A H7N9 virus infection

	Patient 1	Patient 2	Patient 3	Patient 4
RT-PCR	Endotracheal aspirate	Sputum and throat swabs	Throat swab	Sputum
Time between onset of symptoms and collection of first positive specimen (days)	17	15	6	11
Time between onset of symptoms and first positive RT-PCR result (days)	25	15	6	25
M gene*	27	Sputum 34/32/32/34/32/32/−/−; throat −/−/− /− /− /− /− /−	20	27
H7 gene*	25	Sputum 32/30/32/30/30/30/−/−; throat −/−/− /− /− /− /− /−	20	26
N9 gene*	25	Sputum 34/34/36/34/34/34 /−/−; throat −/−/− /− /− /− /− /−	24	28
Viral culture in Madin-Darby canine kidney cells†	Yes	No	Yes	Yes

^*Data are cycle threshold values. Patient 2's RT-PCR results for serial sputa and throat swabs taken on days 15–22 are presented.

^†Cytopathic effects appeared in Madin-Darby canine kidney cells at 48 h after inoculation.