Leptospira infection in rural areas of Uraba region, Colombia: a prospective study

The objective of this study was to analyze the eco-epidemiological aspects of Leptospira seroprevalence and seroincidence, and its associated factors in two municipalities of northwest Colombia. A prospective study was performed in rural areas of Uraba, Antioquia, Colombia. The study enrolled 597 people between November-2015 and January-2016, of which 274 people were followed up one year later. Serologic testing was performed by a microscopic agglutination. The outcomes were seroprevalent and seroincident cases, and the main exposure was an outdoor occupation. A binary and mixed-effect multinomial logistic regression model was used to estimate factors associated with seroprevalent or seroincident cases of Leptospira infection. The overall Leptospira seroprevalence was 27.81% (95%CI:23.62-32.49) and the overall cumulative seroincidence for Leptospira was 14.60% (95%CI:10.33-20.23). Multivariable analysis showed that factors associated with L. interrogans serogroups seropositivity were outdoor occupation, male gender, older age, the presence of dirt soil in the household, and the presence of piglets and opossums. It also showed that factors associated with other Leptospira species serogroups were the presence of pit latrines and of turkeys. In addition, the multivariable model of seroincident cases of L. interrogans serogroups evidenced outdoor occupations, the presence of rats, and corn cultivation as risk factors. Likewise, the multivariable model for seroincident cases of other Leptospira species showed that the presence of hunting canines and cassava cultivation were risk factors. We found specific factors associated with the transmission of Leptospira serogroups contribute to the understanding of the epidemiology of Leptospira infection in rural areas of Uraba, Colombia. AUTHOR SUMMARYMore than one million cases of leptospirosis occur each year, and about 60,000 people die of the disease worldwide. Leptospirosis is a zoonotic bacterial disease imparting its heaviest burden on resource-poor populations. It is also a major cause of economic loss in farm animals causing fetal infections, abortion, stillbirths, infertility, and increased culling rate. Leptospires also contaminate surface waters and survive in mud and moist soils, facilitating transmission among hosts. This complex cycle of transmission makes the disease a suitable model for a one-health approach. This is a prospective study conducted in rural areas of Colombia aimed at identifying the factors associated with seroprevalent and seroincident Leptospira cases. In addition, the results showed that the presence of synanthropic and domestic animals, the characteristics of household materials, and individual variables were factors associated with Leptospira seropositivity. This study clarifies the epidemiology of Leptospira infection and could improve the surveillance program in Colombia, especially in rural areas.