Background:This study was carried out to define the major clinical presentation and laboratory findings of leptospirosis in Guilan province, an agricultural and fishery area in the Caspian littoral.Material/Methods:Cases with a clinically compatible illness and positive serology (immunofluorescence antibody method (IFA)), were included. Clinical information and other lab data were collected.Results:Seventy-four cases, with a mean age of 47.3±12.4 years and of whom 52 (70.3%) were male, were recruited. All had had contact with stagnant water of a farm within the week prior to their admission. Fever and chills were the most frequent chief complaint in 47 (63.5%). Fever, headache, and myalgia were reported by 73 (98.6%), 69 (93.2%), and 57 (77%) cases, respectively. Increased serum creatinine was detected in 18 (27.3%). Only in 27% of patients did CPK rise to 3-fold or more above the Normal Upper Limit, and in 43% of patients its level was within the normal range. Thrombocytopenia was noticed in 87.3%, and 15.5% of cases had platelets less than 20,000/mm[sup]3[/sup]. Anemia was detected in 78.4%. ESR was more than 100 mm/hour in 28.3%.Conclusions:History of fever, headache, and myalgia in patients who have been in contact with the stagnant water of rice fields should raise the possibility of leptospirosis in Guilan province.

Keywords: Leptospirosis - blood, Blood Sedimentation, Creatine Kinase - blood, Creatinine - blood, Fever - etiology, Headache - etiology, Iran, Leptospirosis - transmission, Thrombocytopenia - etiology, Water Microbiology