Brucellosis is one of the most common zoonotic diseases in Iran. Medical services were increased and improved in recent years, but 2679 patients have been reported during the study period in Ardabil province located in the northwest of Iran that is increasing. Men with 59.5% reported the highest incidence of Brucellosis in this study, which was similar to the results achieved by various studies, including studies conducted by Hamzavi et al. in 2014  and Deno et al. in 2010  that have reported that men have the highest incidence rate. Most of the men in Ardabil work in animal husbandry or in butchers and slaughterhouses, hence, they are threatened with more risks in terms of facing livestock, accordingly, men are more prone to be infected with zoonotic diseases such as Brucellosis. We observed most cases in May and June. In general, spring and summer have the highest cases of the disease and the lowest cases were observed in fall and winter. Spring and summer have the most breeding and lactation in livestock and of course, producing livestock and dairy products and the amount of contact with livestock is higher in these seasons, consequently, these seasons have the most cases of the disease. This is in agreement with the findings achieved by many other researchers. [18–19].
Rural regions had more than 69% of patients with Brucellosis in Ardabil province. Accordingly, we can state that Brucellosis in this province causes a problem in rural areas. Villagers' lifestyle who operate in animal husbandry and agriculture and also direct contact with livestock, consuming dairy products that are traditionally prepared by themselves show that it is normal to observe the most cases of the disease in rural regions. There were more than 85% of infected cases in rural regions in Arak, which is much higher than the results achieved by this study , and Isfahan's rural regions also showed the highest number of cases, so that the incidence of the disease in the rural population had been about ten times of the urban population . The results of additional studies in the world prove that a direct relationship is observed between the country's livestock population and their infection with human disease in many countries [21–22].
Spatial analysis of Brucellosis revealed that the disease had a spatial nature and has been distributed in clusters in the northwest of the studied region. Previous research also reveals the cluster distribution of Brucellosis in Iran and other parts of the world . The results achieved by interpolation analysis of brucellosis in this study explained that there are two important centers of the disease in the province, both located in rural regions in the north and center of the province. The north of Aslanduz is the most dangerous center in terms of Brucellosis infection transmission with the risk rate of infection transmission between 13.5 to 15%. This center is a region with high and more traditional animal husbandry and 50% of the inhabitants are nomads with many livestock. Other studies, including studies conducted in China  and the Republic of Azerbaijan , have revealed that high-risk centers in terms of diseases have a direct relationship with the number of cattle kept in the region and depend completely on the job. The east to west of the province has an increasing trend of incidence of Brucellosis, which needs health and educational interventions in these areas.