TABLE 2.

Pathogenicity of rMd5, rMd5-MeqGCN, rMd5ΔMeq, and rMd5-MeqGCNR in SPF MDV maternal-antibody-negative chickens

Virus testeda	No. of chickens affected/total no. tested
	Mortality (%)	Tumor incidence (%)b
rMd5	9/9 (100)	9/9 (100)
rMd5-MeqGCN	0/9 (0)	0/9 (0)
rMd5ΔMeq	0/9 (0)	0/9 (0)
rMd5-MeqGCNRc	3/3 (100)	3/3 (100)
No virus	0/9 (0)	0/9 (0)

^aAll chickens were inoculated with 3,000 PFU of the indicated viruses.

^bChickens that were not positive for gross tumors were further evaluated for microscopic tumors.

^cPerformed as an independent experiment.