We've been a few times. I hadn't heard of it until one year we thought of taking ol' furface with us, and I read about it on a pet forum. That got me looking into it further. I have an aunt in AZ who I later found out contracted it while installing her own sprinkler system, but she didn't get it as bad as your friend (though it still took a few months of antibiotics). Disturbing the ground is often an impetus - stirring up those spores. The Wiki article has figures on incidence & severity.

One trip we looked at new homes, and I was concerned about the dust we were exposed to, so I got tested when I got home - negative.

Doc