ePO 65 – Evaluation of the vector competence of the mosquito aedes albopictus for chikungunya virus: implications for urban health
Manuel Silva1, Líbia Zé-Zé1, Rita Fernandes2, Inês Freitas1, Ricardo Parreira3, Hugo Costa Osório1
1Instituto Nacional de Saúde Dr. Ricardo Jorge, 2Gulbenkian Instituto for Molecular Medicine, 3Instituto de Higiene e Medicina Tropical
Introduction: The establishment of the invasive tiger mosquito (Aedes albopictus) in Algarve, in 2017 (Osório et al., 2018), introduced a critical variable in the epidemiological landscape of Portugal. Despite the vector’s proven role in arboviral outbreaks across the Mediterranean basin (Mariconti et al., 2019), with several chikungunya virus (CHIKV) transmission events reported in Italy and France, data regarding this population’s vector competence remains lacking. This study provides the first experimental evaluation of Algarve’s Ae. albopictus population’s vector competence for CHIKV, assessing the potential for local transmission.
Methodology: Field-derived Ae. albopictus females were presented with an infectious blood meal containing CHIKV. To reconstruct the viral dissemination kinetics, mosquitoes were analysed at 3, 7, 10, and 14 days post-infection (dpi). Tissues were segregated to determine Infection Rates, Dissemination Rates, and Transmission Rates, respectively. Viral detection was performed by RT-PCR, and infectious viral load in saliva was quantified by plaque assay on Vero E6 cells.
Results: The Algarve population exhibited susceptibility to CHIKV infection. Infectious viral particles were recovered from saliva samples as early as 3 dpi, indicating a short extrinsic incubation period and rapid systemic dissemination. Transmission potential was sustained throughout the trial, demonstrating that the physiological barriers to transmission in this population are permeable to the tested viral strain.
Conclusion: These findings confirm that the Ae. albopictus population established in the Algarve is competent to transmit CHIKV. The demonstration of early transmission efficiency suggests that local outbreaks could occur even with limited vector longevity. Consequently, this data showcases the importance of implementing rigorous entomological surveillance to mitigate the risk of autochthonous arboviral transmission in Southern Portugal.
