detection of leptospires serogroups, which are common causes of human acute leptospirosis in guilan, northern iran

background: this study is performed to reveal most common species and subspecies of leptospires that are main causes of hu­man leptospirosis in guilan, northern province of iran. methods: we performed igm-elisa and mat on 282 blood samples from patients who attended to 3 hospitals in the flat area of guilan province with clinical symptoms consisted with leptospirosis.  all specimens with titers ≥ 160 against at least one pathogenic strain in mat and with titers ≥160 in igm-elisa were regarded confirmed positive cases indicative acute dis­ease. for any confirmed positive cases, we determined the strains, which had the highest titer to determine the frequency of most common serovars and serogroups.  results: seventy of 282 sera had titers ≥160 against at least one pathogenic strain in mat and titers ≥ 160 in igm-elisa. we determined frequency of common causative serogroups which had highest titers in 70 positive cases and only cases which had high titers in mat and in igm-elisa were selected which is a reliable criterion to detect acute disease and to deter­mine causative serogroup. conclusion: nine serogroups including sejroe, grippotyphosa, mini, ictero haemorrhagiae, celledoni, autumnalis, cynopteri, pomona, and javanica were more responsible of acute leptospirosis in guilan.