Where did your SIL ‘go out and look for trouble’/get the China Flu?
Everybody thought the coast was clear up till then.
NE Wisconsin has a HUGE outbreak.
I really believe that it depends a lot on the weather. Its been cool and rainy up there. Here, in AZ where I now live, this valley I live in is being studied because of the low incident of that bug. Its been hot, dry, and sunny since the first weeks of May.