From the daily newsletter: a parasite that causes diarrhea is sending people to the hospital across the country. What can we do to stay safe?

A fast-spreading stomach parasite has sickened thousands of people across more than 30 US states.

Cyclospora, a parasitic infection that can cause weeks of severe diarrhea, is spreading in the U.S. Here's what to know about the disease, and how to stay safe.