Table 2. Marek's disease in MDV maternal antibody-negative chickens.

Virus*	No. of chickens that died/no. tested, %	No. of chickens with tumors†/no. tested, %
rMd5	16/17 (94.1)	17/17 (100)
rMd5ΔMeq	1/17 (5.9)‡	0/17 (0)
rMd5ΔMeqR	17/17 (100)	17/17 (100)
None	1/17 (5.9)‡	0/17 (0)

^*All chickens were inoculated with 1,500 pfu of the indicated virus by subcutaneous route.

^†Tumors indicate gross visible MDV-specific lymphoid tumors in visceral organs or nerves.

^‡One chicken from rMd5ΔMeq and uninoculated groups died at day 8 due to nonspecific causes.