Less than 500 cases have been reported to date.After an incubation period of about 8 days (range 3-21 days), patients typically present with the abrupt onset of non-specific signs and symptoms including fever, malaise, headache, chest pain and myalgia/arthralgia, followed rapidly by gastrointestinal manifestations (vomiting, diarrhea, abdominal pain) and, in some cases, a maculopapular skin rash.