Applying the case definition given in Table 2, 62 probable case patients and six patients confirmed by histological proof or DNA isolation from muscle biopsy were seen in Europe, Canada, and Singapore with complaints of myalgia (100 %), fatigue (91 %), fever (82 %), and less frequently headache (59 %) and arthralgia (29 %), with a distinct clustering into early (2 weeks after departure from the island) and late (6 weeks after) phases, and with CPK and blood eosinophilia levels rising distinctively in the second phase during the fifth week after departure. This evidence concerns the gene PIK3C2A and Increased total eosinophil count.