I agree with everything Tom just said.
In my own experience:
I was very sick as a child and seemed to come down with every cold and virus that came along. I eventually grew out of that, but not until my late 20s. I also got food poisoning a few times over the years (I think 3 times, if memory serves). However, I've been keeping snakes and other herps since I was 3 years old (my dad would catch them for me, not because he was a snake guy, but because I begged him to) and I have NEVER caught salmonella or any other bacteria, virus or infection from a snake, lizard, turtle, frog, etc. I didn't start washing my hands (after handling herps) until I was in middle school. I didn't start using anti-bacterial soap until two years ago. I currently keep 18 snakes and a tortoise and I have had snakes bite, crawl, puke, sneeze, crap and musk all over me over the years. No illness, ever. Also, I have seven younger brothers, every one of them has handled reptiles and amphibians and three of them (along with my mom) currently keep snakes and lizards. Again, no illness.
I agree that it is certainly possible to contract salmonella from a reptile and that the same precautions should be taken when handling raw meat. I also don't recommend letting dogs lick your face as they constantly lick e. coli bacteria from their rectums. Strangely, I never hear anyone warn of the danger of becoming infected after engaging in puppy kissing.
Simple, common sense hygiene is all that's required to keep your family disease free in relation to reptiles. I'd be more worried about your child catching something on the playground at school from another kid.
Maybe you should get a written statement from a doctor and maybe a veterinarian to help support your case. That would probably carry the most weight.
Good luck!
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