Among the 395 suspected measles cases without rash, the double-positive rate of measles-specific IgM and viral nucleic acid was 9.6% (38/395), the single-positive rate for measles-specific IgM was 7.3% (29/395), and the single-positive rate for viral nucleic acid was 7.1% (28/395). The gene discussed is CD40LG; the disease is measles.