How does the author use foreshadowing in Running Out of Time?

In Chapter One, we learn that many children in Clifton are getting sick, and Jessie gives some valuable information to the reader. She comments on the fact that Dr. Fister used to give out pills, but has recently been giving other remedies that do not work. This foreshadows the problems that are about to befall Clifton. Jessie and Ma are mystified that the pills have stopped and Jessie becomes worried because all the adults seem so scared.