Stomach flu

Nature 
Stomach "flu" is universal, and for most people a private, and usually temporary, annoyance. The symptoms are nausea in the stomach, aches, fever and vomiting. It is not a form of influenza, but an inflammation of the intestinal tract (gastroenteritis) due to an infectious agent -- either a virus, bacterium or parasite. About 50% of stomach "flu" is caused by on of the 10 or so variation of the Norwalk virus, particularly in winter months.
Broader 
Type 
(E) Emanations of other problems