Monitoring vector-borne diseases: A study in Italy and Greece

Rapid urbanisation and environmental changes are reshaping mosquito population dynamics and the transmission of vector-borne pathogens. Culex pipiens and Aedes albopictus have successfully adapted to anthropogenic environments, becoming key vectors of emerging and re-emerging arboviruses and filarial parasites. This study conducted a comparative entomological and pathogen surveillance between 2022 and 2023 in central Italy and Crete to assess species composition, population dynamics, and circulation of arboviruses and filarial nematodes across different ecological contexts. In Italy, a total of 22,757 mosquitoes were collected, with Cx. pipiens (~86%) and Ae. albopictus (~12%) being the predominant species. Significant temporal variations in mosquito diversity and frequency were observed. In 2022, molecular screening detected Usutu virus (USUV) in Cx. pipiens in central Italy, with the first report of co-circulation of USUV and Setaria nematodes. In 2023, co-circulation of West Nile virus (WNV Lineage 2) and USUV was identified in Cx. pipiens from the Marche region. In Crete, 791 mosquitoes were collected, with Culex species dominating the assemblages. The highest mosquito biodiversity was recorded in peri-urban areas, exhibiting temporal variation. Molecular screening detected Dirofilaria repens in Ae. albopictus. No evidence of WNV or USUV circulation was found. We provide the first integrated, regional-scale assessment of mosquito vectors and vector-borne pathogens across two ecologically distinct Mediterranean regions. By combining complementary surveillance components, including mosquito species composition, biodiversity, seasonal abundance, habitat characteristics, and molecular detection of arboviruses and filarial nematodes, our study provides a comprehensive understanding of vector-pathogen dynamics across contrasting ecological settings. Our findings demonstrate that environmental and ecological drivers strongly influence mosquito community structure and pathogen circulation, highlighting the value of integrated, region-specific surveillance as a foundation for evidence-based vector control and public health decision-making.