A parasitic infection that causes miserable bouts of “explosive” diarrhea is surging across the United States at rates that appear to be higher than this time last year.

Health officials in Mecklenburg County are warning residents after a rise in cases of a stomach parasite that causes diarrhea and fatigue.

It confirmed 843 cases and 86 hospitalizations as of July 9, with a further 1,500 cases under investigation.