P0047 Evidence of Zika virus circulation in Mali Elif Nurtop*1, Issa Diarra1, Boris Pastorino1, Bourèma Kouriba2, Abdoul Karim Sangare2, Nathanaël Hozé3, Simon Cauchemez3, Stéphane Priet1, Xavier De Lamballerie1 1 Emerging Virus Unit, Aix-Marseille University, Marseille, France, 2 Malaria Research and Training Center, Bamako, Mali, 3 Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, Paris, France Background: Zika virus was first isolated from a sentinel monkey in Uganda, in 1947. However, it took public attention years later, in 2016, when it reached to the Americas and associated with severe congenital malformations. Even though ZIKV was originated in Africa, little is known about the situation in the continent, mainly due to the lack of noticeable outbreaks. Accordingly, in this report, we focused on ZIKV seroprevalence in Mali, where the only data concerning ZIKV was reported in 1970. Materials/methods: A total of 793 serum specimens were included. Samples were collected between July- October 2016 from asymptomatic volunteers residing in 7 different sites (Niono, Bamako, Kadiolo, Bougouni, Kita, Bandiagara, Diema) of Mali. The sera were primarily tested with anti-NS1 ZIKV IgG ELISA and non-negatives were confirmed with Cytopathic Effect-based Virus Neutralisation Test. Statistical and transmission modeling analyses were performed. Results: The overall seropositivity of ZIKV was estimated as 11.98%, ranging from 3.1% to 20.2% in different sites. We found increased ZIKV seroprevalence with age (p=0.003). Globally, no statistical difference was detected between genders (11.6 % in male and 12.2% in female, p=0.834). Transmission modeling analysis estimated epidemic transmission in Bougouni, Kadiolo and Bandiagara between 1995 and 2000. However, for other study sites, it was unclear if there was an epidemic after 2000 or the transmission was endemic. When the seroprevalence in different climatic zones were investigated; we identified that the transmission of ZIKV is endemic in tropical regions (Kita, Bamako, Bougouni, Kadiolo), whereas in semi-arid (Diema, Niano, Bandiagara) it is epidemic. The incidence rates were estimated at a varying percentage; lowest in Bamako with 0.8% and highest in Diema with 6.7%. Conclusions: The estimated ZIKV seropositivity (~12%) in Mali points out that the majority of the population is immunologically naïve against ZIKV infections and the importation of ZIKV adapted to urban mosquitoes may lead to an outbreak in the country. In this cross-sectional study, we intended to characterize the prevalence of ZIKV in Mali which will ultimately allow estimating the level of immunity of the local populations and identify those vulnerable to possible future epidemics. 29TH ECCMID 13-16 APRIL 2019 AMSTERDAM, NETHERLANDS POWERED BY M-ANAGE.COM .