BACKGROUND: Leptospirosis is a zoonotic disease with a worldwide spread, which is very important from two aspects, health concerns in human societies and economic losses due to abortion, stillbirth, birth of weak calves,  Milk-drop syndrome and mastitis and death. The prevalence of an infection at the herd or animal level is a key issue that determines whether the infection should be considered important and which measures and policies should be made and applied. OBJECTIVES: The aim of this search is a meta-analysis study of  the prevalence of leptospirosis and serovars of leptospira interrogans in Iran. METHODS: The search was carried out by relevant literature search from 1997 to 2017 and by keywords: Iran, leptospira, cattle, sheep, goats, buffaloes, camel, and their combination in data banks of Magiran, SID, Iranmedex, PubMed and Google scholar. In this study, 39 articles were finally accepted. For statistical analysis, prevalence rates were entered in the Comprehensive Meta Analysis (CMA) software. RESULTS: The prevalence of leptospirosis in apparently healthy ruminants was 21.5% (95% CI: 17.8-25.8) and Grippotyphosa, Pomona and Canicola were the most prevalent. CONCLUSIONS: According to the high prevalence of pomona in our results, using this serovar in produced vaccines inside the country, applying preventive methods to control infection in herd dogs and gaining a share of the health system budget can have a good effect on for leptospira control program.

BACKGROUND: Leptospirosis is a common bacterial disease in humans and livestock, which leads to reduced production and reproductive disorders in ruminants and also causes major economic losses to villagers and farmers. OBJECTIVES: The purpose of this study was to investigate the seroprevalence of different Leptospira interrogans serovars in ruminants population of Lorestan province and assess the role of environmental and host factors on the severity of the serological infection. METHODS: For this purpose, referring to livestock and sheep and goat flocks in different cities of Lorestan province, 691 blood samples were collected including 258 sheep, 195 goats and 238 cows, and then, the point of infection with seven different serovars of Leptospira interogans was assessed using microscopic agglutination test. Hosting factors such as age, gender and also environmental factors including geographical area, rainfall, temperature, relative humidity and altitude of sampling area from the sea level were recorded, and their probable role in the seroprevalence was statistically analyzed. RESULTS: Results of this study showed that the overall prevalence of leptospirosis in cattle, sheep, and goats examined in the Lorestan province was 26.05 % (95 % CI: 19.7-31.23), 22.48 % (95 % CI: 16.95-25.16) and 14.87% (95 % CI: 9.37-20.36), respectively. There was no statistically significant (p < /em>>0.05) difference from the point of age groups and sexes. The most prevalent contaminant serovars for cows, sheep, and goats with seropositive reaction against leptospira were grippotyphosa (41.93%), canicola (32.76%) and canicola (48.27 %), respectively. The results showed environmental factors including relative humidity (p < /em>=0.02), annual rainfall (p < /em>=0.001) and altitude from the sea level of sampling location (p < /em>=0.03) have a significant effect but the annual temperature does not have a significant effect (p < /em><0.05) on the seroprevalence of Leptospira. Also, more positive reactive animals in the eastern and western areas of Lorestan province were found (p < /em>>0.05). CONCLUSIONS: Leptospirosis is endemic in livestock population of Lorestan province and environmental factors play a significant role in the severity of infection, which increases the need for attention to the geographical areas at risk.