Human leptospirosis in northern Iran: a population-based epidemiological study using infectious disease surveillance system data.

OBJECTIVE

Human leptospirosis is an endemic disease in northern Iran. residents of northern provinces are at increased risk of exposure to Leptospira due to the region's unique geographical characteristics, occupational patterns, cultural practices, lifestyle, and recreational activities, all of which contribute to the higher burden of the disease in this area. Therefore, this study aimed to examine the epidemiological patterns of leptospirosis in Babol County over six years (2019-2024).

RESULTS

During the study period, 344 cases of human leptospirosis were reported. Of these, 86.0% occurred in males, and 70.3% of the cases were among rural residents. Among occupational groups, agricultural workers exhibited the highest frequency, with 42.4% of cases occurring among rice farmers and 22.1% among other farmers. The crude and age-standardized incidence rates of leptospirosis in 2019 were 10.1 and 8.1 per 100,000 population, respectively. These rates showed an increasing trend over the study period, reaching 17.3 and 14.4 per 100,000 population in 2024. The upward trend was statistically significant (P < 0.001). During the study period, the highest incidence was observed in May, with a rate of 2.9 per 100,000 population.