Fig. 4.

Retrospective study. (a) ELISA Ig G results for leptosirosis. The solid line (––) is the mean optical density (OD), the dotted line (- - - -) the cut-off level for positivity. Only one patient was completely IgG-negative (OD = 0·0), shown as an open symbol on the baseline of OD = 0. (b) ELISA IgG results for hantaviruses, Hantaan virus (HTNV) and Puumala virus (PUUV). Results are expressed as Q values (observed OD/control cut-off OD), where Q values >1 (- - - -) are considered as positives. Six patients had IgG levels positive for PUUV, where two cross-reacted also with HTNV. No case had exclusive HTNV seroreactivity. The only patient seronegative for leptospirosis is shown in red.