Seroprevalence of Leptospira interrogans infection in Equids of Lorestan Province: Investigation the role of probable risk factors

Environmental and hosts risk factors are considered as two essential elements in epidemiological studies of infectious diseases. The severity of the infection and also the chance of transmission of pathogenic Leptospira interrogans bacteria from herbivores to humans have always been exposed to environmental and hosts risk factors. This study aimed to investigate the presence of serum reaction in the equid's population of Lorestan province and the determination of native serovars as well as evaluation of the role of environmental and host factors on seroprevalence. A total of 327 equids including 223 horses, 46 mules, and 58 donkeys were sampled and sera samples evaluated against 7 different Leptospira interrogans serovars. Geographical location and environmental conditions of sampled areas were recorded to be used in statistical surveys. The results showed that the serum positive reaction rate in horses, mules, and donkeys was 18.38, 10.87 and 3.45%, respectively. Host risk factors such as sex, age, and breed were effective on serum response rate and a significant difference was found. Canicola serovar with 46.34, 100 and 60% infection in horses, donkeys, and mules, respectively was the most common infective serovar; but a significant difference was not observed between animal species. Also, the results indicated that annual temperature of the environment and altitude at sea level of sampled location have a significant effect on seroprevalence of leptospirosis, but relative humidity and annual rainfall did not have a significant effect. Results of the current study proved that infection with Leptospira interrogans, although in Lorestan province is less severe than in other parts of the country, the most important native serovar of this region is canicola.