Among the blood samples of 186 patients with suspected leptospirosis who met the inclusion criteria, including having a fever for more than 5 days (November 2021–June 2022), 88 samples (47%) were Leptospira-positive according to IgM LAT, IgM ELISA, or nested PCR (positivity rates: 38%, 37%, and 42%, respectively). This evidence concerns the gene CD40LG and leptospirosis.