H., I'm a new mom so I'm learning how hard it is to see our kids sick. I feel for you. My son just got over rotavirus and I was desperate to blame myself, or anybody I could... but its not like it would have helped him... it's just so hard to see them uncomfortable.
I also work for a school district though, and I have to agree with the other mom's... especially the one that said that the only way you could blame the school is if she got MRSA or Ecoli or something of that nature. I think the people that transferred their kids and said they got sick less are comparing apples and oranges (i.o.w. it was just a coincidence)... but if you actually think that's possible, maybe you should try to get your daughter transferred? Going along with what everyone else said about germs being airborn, I want to throw a different perspective your way.
When I was young I ALWAYS seemed to have Strep Throat. After I got over it, everyone in my class got it (oops.... sorry). It was a never ending cycle. Then, one day, my little sister's throat swelled up and she had to have her tonsils out. It turned out that she was the host of the strep throat all along... she never really had it or any symptoms... but she kept passing it to me and me to my classmates. After she got her tonsils out me and my classmates were pretty much strep free for the rest of the year and I only seemed to get it once a year as opposed to monthly or bi-monthly like before.
So to wrap up my long story... maybe there is someone in that school acting as a host, like my sister was. They probably don't even know they're doing it because they aren't getting sick themselves.