West nile virus seroprevalence in Manisa province

Introduction and Aim: West Nile Virus (WNV), which causes widespread outbreaks in different parts of the world, is a risk to public health due to its existence in our country. Community-based study data are needed to identify measures to be taken against possible outbreaks. The aim of this study was to determine the seroprevalence of community-based WNV in Manisa and to investigate the relationship between sociodemographic and socioeconomic variables and the seroprevalence. Method: The population of the study consists of all individuals older than two years of age (N = 1,317,917) registered in Manisa Province Family Medicine Information System in October 2013. Assuming the expected seroprevalence value of 2.5% in the research area, the minimum sample size was calculated as 753 with 95% confidence interval and 1% deviation. The study was conducted on 1233 people. Selected participants were determined by simple random sampling method. Participants were invited to the Family Health Centers where they were registered, questionnaires were completed and blood samples were taken. Samples were stored at -80 C until the study date. Specific IgG and IgM antibodies against WNV were investigated in serum samples using a commercial ELISA method and these parameters were dependent variables of the study. The results were interpreted according to the manufacturer's instructions. Borderline results were considered negative. The relationship between age, gender, location, education and income level, occupation, population density, altitude, toilet position in the household, the presence of hypertension-diabetes mellitus-cardiovascular disease variables was analyzed chi-square, Fisher's exact test and t test. Adjusted Odds Ratio (OR) and 95% confidence intervals for each variable were calculated by logistic regression method to explain potential risks. Ethical approval for the study was accepted from Dokuz Eylül University Non-Interventional Ethics Committees on 13.08.2018. Results: WNV IgM antibodies were detected in 17 (1.4%) and WNV IgG antibodies were detected in 47 sera (3.8%) by ELISA. No significant association was found between risk factors and WNV IgM prevalence. WNV IgG prevalence was significantly correlated with independent variables of advanced age, presence of hypertension, diabetes mellitus and cardiovascular disease, low level of education and income, living in low altitude area and the location of the toilet. In multivariate analysis; age (every one year increase) (OR = 1.049, CI 1,025-1,073, p <0.001), equivalent annual income per capita below 3265 TL (OR = 3,21, CI 1,534-6,731, p = 0.002) living areas below 132 meters altitude (OR = 3,21, CI 1,265-8,158, p = 0.014) were found to be the risk factors for WNV seropositivity. Conclusion: Seroprevalence of WNV IgG was found to be 3.8% in Manisa Province. Advanced age, low income and living at low altitude areas have a significant effect on seropositivity. Key Words: West Nile Virus, Seroprevalence, ELISA