Seroprevalence Of Zika, Chikungunya And Dengue Viruses In A Rural Area Of Northeastern Brazil

Background: The Dengue virus (DENV) has been in circulation in Brazil for decades, resulting in the occurrence of several outbreaks. The emergence of Chikungunya virus (CHIKV) in 2014 and Zika virus (ZIKV) in 2015 has raised new concerns raised about the prevalence of these arboviruses. Concurrent outbreaks of DENV, CHIKV and ZIKV have taken place in Brazil since 2015, notably in major cities throughout the country's northeastern region. While the state of Bahia has been heavily affected by CHIKV and ZIKV outbreaks, the true burden of these infections remains hidden due to the predominance of asymptomatic infection. A previous study estimated ZIKV seroprevalence to be 63% in Salvador, the capital of the state of Bahia. Methods and materials: In 2019, a cross-sectional study was performed in Conde, a small city located 170 km from Salvador, to verify the seroprevalence of DENV, CHIK and ZIKV in consecutive residents from peri-urban and rural communities. Sociodemographic data and sera samples were obtained and tested by ELISA for IgG against DENV, CHIKV and ZIKV. Results: A total of 336 individuals were enrolled: 165 from a peri-urban community and 176 from a rural community. In the rural area, the median age of participants was 23 years (IQ 14–42.5), while the median age was 34 years (IQ 18-47) in the peri-urban location. IgG antibodies against ZIKV, DENV and CHIKV were detected in 1,7%, 17% and 0% of rural participants, respectively. In the peri-urban region, IgG antibodies against ZIKV, DENV and CHIKV were detected in 41%, 73% and 11% of these residents, respectively. Conclusion: Our findings indicate that rates of previous exposure to ZIKV, DENV and CHIKV in the evaluated peri-urban population are similar to those found in large urban centers in northeastern Brazil. In addition, the circulation of ZIKV and CHIKV was found to be very low in the rural community studied. Accordingly, many individuals residing in rural areas in the state may be susceptible to future outbreaks of these arboviruses. The identification of susceptible populations is crucial to the implementation of future prevention and control measures.