Leptospirosis is a major public health problem in Thailand. A description on epidemiology of the disease could increase understanding of
leptospirosis and suggest potential prevention and control measures. Data on human leptospirosis cases from all 77 provinces in Thailand
were collected based on the national surveillance criteria. Univariate analysis and multiple logistic regression were conducted to describe
occurrence of leptospirosis cases and risk factors for mortality. From 2003 to 2012, there were 41,089 cases of leptospirosis reported to
Bureau of Epidemiology, Ministry of Public Health, Thailand. Average annual incidence rate was 6.6 per 100,000 population. Northeastern
region showed the highest incidence (12.5 per 100,000 population). There were 606 deaths, with case fatality rate 1.5%. Seasonal
variation was observed, with the highest incidence during rainy season from August to October. Ratio of male to female cases was 3.5:1.
Adults aged 55-64 years had the highest incidence rate (9.9 per 100,000 population). There were 72.3% of the cases that worked in
agricultural sector. Delay in seeking treatment, which was beyond three days after onset, significantly increased the risk of death
(adjusted odds ratio = 1.8, 95% CI = 1.53-2.19)