The diagnosis of leptospirosis was confirmed based on MAT seroconversion in 7 dogs (1b), a single positive MAT titer in 3 dogs (1c), a positive IgM lateral flow assay in 1 dog (1d), and strongly suggestive clinical signs with 3 of the 4 classical manifestations of leptospirosis in 4 dogs (1e). Here, CD40LG is linked to leptospirosis.