Pathobiology of Tennessee 2017 H7N9 low and high pathogenicity avian influenza viruses in commercial broiler breeders and specific pathogen free layer chickens

Table 2 Virus detection and titers in tissues from broiler breeders and SPF White Leghorn chickens inoculated with Tennessee 2017 H7N9 LPAI or HPAI viruses

Bird type (age)	Pathotype	Day post-challenge	No. with virus detected/total (titer as log₁₀ EID₅₀/g)^d
Bird type (age)	Pathotype	Day post-challenge	Lung	Spleen	Heart	Brain	Muscle	Reproductive tract^e
Broiler breeders (36w)^a	LP	3	0/3	0/3	0/3	0/3	0/3	0/3
SPF White Leghorn (4w)^b	LP	3	0/2	0/2	0/2	0/2	0/2	nd
SPF White Leghorn (4w)^c	HP	2	2/2 (7.2 ± 0.3)	2/2 (7.3 ± 0.2)	2/2 (8.3 ± 0.3)	2/2 (7.0 ± 0.6)	2/2 (7.5 ± 0.4)	nd

Virus detection by qRRT-PCR.
nd: not determined.
^aTissues from 3 broiler breeders necropsied at 3 dpc. The threshold of detection in tissues was 1.9 log₁₀ EID₅₀/g for H7N9 LPAI virus.
^bTissues from 2 SPF layer birds necropsied at 3 dpc. The threshold of detection in tissues was 1.9 log₁₀ EID₅₀/g for H7N9 LPAI virus.
^cTissues from 2 SPF layer birds necropsied at 2 dpc. The threshold of detection in tissues was 2.5 log₁₀ EID₅₀/g for H7N9 HPAI virus.
^dMean titer ± SD.
^eAll sections of the reproductive tract were tested: ovary, infundibulum, magnum, isthmus, and shell gland.

ISSN: 1297-9716