My 6 month old cat was the sweetest cat we ever had. He always played with my children and would jump on our beds at night and sleep with us. About 2 weeks ago we went out of town for a day, came back and he would not jump off any furniture. He would jump off the couch and his back legs would give out. He basically belly flopped. Now he cannot stand up without slipping and falling. We do not let him outside except for when he goes on our porch, which is very seldom. We have taken him to the Vet twice now, the X-rays showed no injury to the spine which is what the Vet though it might be. He is on medication now but it has been two weeks and he has gotten worse. I now have to carry him upstairs for him to use the litter box because he cannot walk upstairs under his own power. Is there any chance it could be a disease or some type of Illness from going outside?I have looked everywhere online and found nothing, please help.