The disease was first identified in 1968 and is caused by the Norwalk virus , a small, highly infectious virus that is transmitted especially in times of very cold and causes abdominal cramps, fever, explosive diarrhea, and vomiting. Symptoms usually resolve within 24/48 hours. Parasitizes the small intestine, widening the intestinal villi, while decreasing the motility of the stomach. Its outbreaks are related to collective meals in camps, schools, cruise ships, nursing homes , etc.
It belongs to the calicivirus family, which are naked viruses 27 nanometers in diameter and shaped like a calyx when viewed through the electron microscope. Hawaii virus, Desert Storm virus and Mountain Snow virus also belong to this family of infectious agents.
