CD40LG and infection: Probable infection was defined as IgM titre ≥1:400 to O. tsutsugamushi, an IgM titre of ≥1:800 or IgG ≥1:1600 to R. typhi or an IgG titre of ≥1:200 to R. honeii or R. conorii. Univariate and multivariable logistic regression was used to identify associations.