DDIAS and interstitial nephritis: Furthermore, renal fibrosis was analyzed by staining of interstitial collagen deposition of kidney sections and by molecular quantification of mRNA transcripts of fibroblast activation marker (collagen1 A1, ColA1) and inducible nitric oxide (iNOS) which play a role in Leptospira-induced interstitial nephritis [13] and induction of kidney fibrosis [16].