Underdiagnosis of arbovirus infections in returned travelers in an area with growing circulation of Aedes albopictus in North-Eastern France

Background: Vector-borne diseases such as malaria and arboviruses are common etiologies of post-travel fever. Methods: After excluding malaria, we retrospectively analyzed the diagnosis of dengue virus (DENV), chikungunya virus (CHIKV), and zika virus (ZIKV) infections following recent travel by patients treated at the Strasbourg University Hospital between 2014 and 2023. Available serums (n = 35) sampled in 2023 were retrospectively tested for DENV, CHIKV, and ZIKV infections. Results: Our results showed that 78% of the 915 malaria-negative patients without changes over the course of ten years had not undergone arbovirus infection testing. Retrospective testing revealed missing arbovirus infections: two DENV infections and one CHIKV infection, representing 8.6% (3/35) of patients for whom no mandatory declaration or vector control could be undertaken. Conclusion: Our results highlight the need for early case detection, particularly in the context of the upcoming 2024 Olympic Games.