Serbia multidisciplinary approach for surveillance and risk identification – The “One Health” information for action

Abstract Issue/problem To date, Serbia has not detected locally acquired Dengue cases. Since a competent Dengue virus vector Aedes albopictus (Ae. albopictus) has been detected since 2017, imported cases have the potential to trigger local transmission. Description of the problem To ensure preparedness and timely response in the event of an epidemic signal in Serbia, we described the imported Dengue cases and analysed the geographical distribution and density of the vector. Probable and confirmed imported cases meeting the 2018 EU case definition were reported via the National Notifiable System between January 2019 and December 2023. We monitored the density and geographical spread of mosquitos, including Ae. albopictus, which were collected during May-October 2022 and 2023. Mosquito genera were determined according to morphological criteria and DNA barcoding. Results During the investigation period, physicians reported three probable and four confirmed imported Dengue cases; the mean age was 28.4 (standard deviation (SD)=11.5) years and 57% were male. Cases had travelled in Southeast Asia (n = 6) and the Caribbean (n = 1). The mean time interval from symptom onset to seeking medical care was 3.6 (SD = 2.1) days and from symptom onset to laboratory confirmation 7.4 (SD = 6.3) days. We collected 1994 Ae. albopictus mosquitoes in 308 sampling sites across 12 Serbian regions. We observed the highest number of mosquitoes in September (38%, p < 0.001) and in the Belgrade region (81%, p < 0.001). In 2022, we detected Ae. albopictus mosquitos in seven regions and in 2023 in nine. Lessons Ae. albopictus mosquitoes were widely distributed in Serbia, with the highest presence during September and in the capital region. The importation of Dengue cases from affected countries underscores the need for enhanced integrated and “real-time” surveillance linked with vector control activities.