Résumé
Environmental changes, including the geographic expansion of vector arthropods (mosquitoes, ticks), are altering the global distribution of multiple arboviruses, such as Dengue (DENV), Zika (ZIKV), Chikungunya (CHIKV), West Nile (WNV), Usutu (USUV), and Crimean-Congo hemorrhagic fever (CCHFV). Consequently, there has been a significant increase in the number of diagnosed cases of arboviruses, whether imported or locally acquired, particularly in southern mainland France. Although reporting of these cases is mandatory, clinical signs are often non-specific, and pauci- or asymptomatic forms are frequent, making it likely that the real extent of their spread is underestimated, in particular in eastern Occitanie. Objective: our aim was to assess the seroprevalence of arboviruses in the general population consulting in general practice for routine care. To this end, we conducted a multicenter cross-sectional epidemiological study in six University Multidisciplinary Health Centers located in three departments: Gard, Hérault, and Pyrénées-Orientales. A short questionnaire was administered to participants, and two drops of capillary blood were collected using a lancet on filter paper (DBS). The samples were then analyzed by multiplex serology (Luminex®) to detect IgG antibodies against the arboviruses DENV, ZIKV, CHIKV, WNV, USUV, CCHFV, ONNV, and RVFV. Results: a total of 629 patients were included. The IgG seroprevalence was 1.43% for DENV [95% CI: 0.75; 2.69], 5.56% for CHIKV [95% CI: 3.90; 7.65], 0.48% for ZIKV [95% CI: 0.06; 1.01], and 0.63% for WNV [95% CI: 0.17; 1.62]. Cutoffs were sought for the other arboviruses included in the panel for which the test had not yet been validated, allowing us to conclude with minimum and maximum point estimates of prevalence ranging from [0.32% to 1.59%] for ONNV, [0.48% to 0.63%] for USUV, [0.48% to 4.93%] for CCHFV, and [1.75% to 1.90%] for RVFV. Conclusion: our study highlights a low prevalence of the arboviruses investigated but documents viral circulation that escapes the current surveillance system for DENV, CHIKV, ZIKV, and WNV, with the identification of patients -particularly for DENV- who had not traveled. We also identified positive signals for USUV, ONNV, RVFV, and CCHFV, which require further investigation but cannot rule out the potential circulation of these agents in the region. Given the growing threat and increasing number of imported cases, our pilot study reveals the need to adapt the arbovirus surveillance network in our territory.