I agree with the above. If you're not seeing any excess mucus or slight open mouth breathing, it could definitely be that he's just hissing at you. When my bp was young and pretty small, she would hiss every once and awhile when I went to pick her up because she was scared, and you could hear it... it wasn't loud, but you could hear it. Just to be on the safe side though, I would still sanitize anything that comes in contact with him, but if he's eating/drinking/seems healthy and happy, then he probably is!