These days kiba was really upset because of akamaru getting that dangerous bacteria. The bacteria would make akamaru to lost his personality and control eventually and turn to a really dangerous monster. As others and Tsunade said. But kiba didn't want to believe that he was losing akamaru. Akamaru was really precious to him after all. If all ninjas in the village would try to kill Akamaru, kiba wouldn't let them and if he couldn't protect Akamaru he would rather die with him. So easily...

You just went to his house and see akamaru you wanted to caress his head as you always used to do but he just bited your hand hardly.