In this Friday, Jan. 10, 2014 photo, an Indian worker holds two lion cubs at Patna Zoo, in Patna, India. India is scrambling to protect its beleaguered tiger population after several big cats tested positive for a virus common among dogs but deadly to other carnivores, experts said. In the last year, canine distemper virus has killed at least four tigers and several other animals across northern and eastern India, according to Rajesh Gopal of the government’s National Tiger Conservation Authority. (AP Photo/Aftab Alam Siddiqui)