Seroprevalence of West Nile virus, Crimean-Congo hemorrhagic fever virus, Francisella tularensis and Borrelia burgdorferi in rural population of Manisa, western Turkey

Background & objectives: Zoonotic diseases are well recognised threat to public health globally. The information of regional prevalence and associated risk factors allow the national programmes to determine and frame better strategies for their control, as they also provide the actual status of zoonosis in the region. The aim of this study was to determine the seroprevalence of West Nile virus (WNV), Crimean-Congo hemorrhagic fever virus (CCHFV), Francisella tularensis and Borrelia burgdorferi among the rural residents of Manisa region, Turkey and to identify the associated risk factors. Methods: Cross sectional study was conducted in rural parts of Manisa, Aegean region of western Turkey in 2012. Blood samples from 324 randomly selected subjects were screened for the presence of IgG antibodies to WNV, CCHFV, F. tularensis and B. burgdorferi with commercially available kits. The demographic structure of the rural residents and risk factors related to lifestyle such as outdoor agriculture activities, animal husbandry, hunting and history of tick bite were questioned and their relationships with positive results were analyzed statistically. Results: It was observed that 49 subjects (15%) had IgG antibodies to at least one of the zoonotic agents studied. The seroprevalence of F. tularensis was highest with a percentage of 7.1% (n = 23). Distribution of the positive results for WNV, CCHFV and B. burgdorferi were 4.3% (n = 14), 3.7% (n = 12) and 0.9% (n = 3), respectively. Older age and uncompleted secondary education were the statistically significant risk factors for seropositivity to at least one zoonotic agent investigated. Logistic regression analyses confirmed that older age (over 50) increased the risk of WNV and CCHFV seropositivity. Interpretation & conclusion: Seropositivity rates were not found to be higher than the expected rates. Further, studies are needed to evaluate the threat of vector borne zoonoses and associated risk factors in the study area.