Complex sentence: The most common symptoms are vomiting and diarrhea however additional symptoms may occur, these include: chills, nausea, headache, abdominal cramps, and myalgia--fever is very rare.
Split into simpler sentences: The most common symptoms are vomiting and diarrhea however additional symptoms may occur. These include: chills, nausea, headache, abdominal cramps, and myalgia--fever is very rare.