Cross-sectional entomological data reveals an increased risk of arboviral transmission in a year of record-breaking heat in Southern Europe

Résumé fourni par la source

In 2023, an unprecedentedly high number of locally acquired cases of dengue virus occurred in Europe, including the first large outbreak in Rome (Italy). Globally, 2023 was warmer than any previous year on record since 1850, with each month from June to December being warmer than the corresponding month in previous years. We conducted an extensive analysis of entomological data in Rome to investigate how the unprecedentedly high temperatures seen in 2023 affected the abundance and seasonal dynamics of the local vector Aedes albopictus population and the risk of autochthonous transmission of both dengue and chikungunya viruses. We applied a mathematical dynamic temperature-based model to analyse adult mosquito collections in 2023 compared to those available for 2012 and assess the consequent changes in the risk of arboviral transmission. Simulations of potential local transmission triggered by disease importation were used to evaluate the effectiveness of human and entomological surveillance for monitoring transmission risks, providing insights for future action plans Results highlight a higher abundance and longer active season of Ae. albopictus as well as a higher risk of local arbovirus transmission in 2023. Our findings raise concern in light of the predictions for more frequent extremely warm years in Europe in the near future. Virgillito et al. assess the abundance and the active season of Ae. albopictus, as well as the risk of local arbovirus transmission, in a metropolitan Mediterranean area in a year of record-breaking heat. All are enhanced, raising concern given more frequent extremely warm years are predicted in Europe in the future. The Tiger mosquito can transmit the dengue and chikungunya viruses to humans, which cause disease. In 2023, unusually warm temperatures were seen in Rome. We compared the abundance of the Tiger Mosquito between 2012 and 2023 in Rome. We used a mathematical model to estimate that there was a higher mosquito density in 2023, resulting in a longer duration of potential risk of infection of people with dengue and chikungunya viruses and a greater number of urban sites at which infection could occur. Our findings provide evidence of an increasing risk of transmission of these two viruses in Mediterranean urban areas, underscoring the critical importance of timely case detection and rapid mosquito control responses to prevent potential outbreaks in urbanised settings.

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