In the absence of any obvious reason for the behaviour, take him to the vet for a full check up. Make sure he checks the mouth and ears for a possible abscess, and his skin around his collar for sores...his entire body for sores.
Go back and visualize your approach step-by-step, your walk, your attitude, his stance, his tail, position of his head - was it down between his shoulders or up? Was he vocalizing - whining, barking, growling? Was his tail pointing straight out, was it wagging? Were his lips curled back, was his mouth open and was he panting? Was he standing stiffly or licking his lips? The Devil (and the reason) are in the details.
Is there anything else that you would like to add, that you omitted, that would lend itself to clarifying the situation?
You didn't answer whether you were the dog's owner or whether it was a parent's or partner's dog. All you said is you were returning from school. The problem, as I see it, is you're saying a previously stable, 15 month old male Corso with whom you have enjoyed a good relationship, derailed and without provocation - a breed that is generally non biting - bit you, a familiar family member - without warning and without cause. You are in the enviable position of being able to explain the events leading up to the bite whereas the dog is mute on the subject.
If there was no negative history with the animal and nothing different in how you entered the yard, and if no medical reason can be found - no rabies, no distemper, no painful sore reacting to your touch, I'd be left with the impression that you left some pertinent details out.
Go back and visualize your approach step-by-step, your walk, your attitude, his stance, his tail, position of his head - was it down between his shoulders or up? Was he vocalizing - whining, barking, growling? Was his tail pointing straight out, was it wagging? Were his lips curled back, was his mouth open and was he panting? Was he standing stiffly or licking his lips? The Devil (and the reason) are in the details.
Is there anything else that you would like to add, that you omitted, that would lend itself to clarifying the situation?
You didn't answer whether you were the dog's owner or whether it was a parent's or partner's dog. All you said is you were returning from school. The problem, as I see it, is you're saying a previously stable, 15 month old male Corso with whom you have enjoyed a good relationship, derailed and without provocation - a breed that is generally non biting - bit you, a familiar family member - without warning and without cause. You are in the enviable position of being able to explain the events leading up to the bite whereas the dog is mute on the subject.
If there was no negative history with the animal and nothing different in how you entered the yard, and if no medical reason can be found - no rabies, no distemper, no painful sore reacting to your touch, I'd be left with the impression that you left some pertinent details out.