Delacour-Estrella, S. | bioRxiv Science

bioRxiv2026

Are mosquito species present in Spain competent for Oropouche virus?

Oropouche virus (OROV; Orthobunyavirus) is an emerging arbovirus endemic to South America and the Caribbean, with imported cases in European countries, including Spain. Although primarily transmitted by biting midges (Culicoides spp.), OROV has been detected in several mosquito species, raising concerns about potential establishment in non-endemic regions. European populations of Aedes albopictus, and Culex pipiens, as well as the invasive Aedes aegypti, represent relevant models for assessing vector competence. Here, we evaluated vector competence of Spanish Cx. pipiens biotype molestus, Spanish Ae. albopictus, and Ae. aegypti (Liverpool strain), for the 2024 OROV outbreak strain. Female mosquitoes were orally exposed to infectious blood meals and maintained under controlled insectary conditions. In addition, an additional group received a second non-infectious blood meal. The survival of the mosquitoes was monitored, and infection, dissemination, and transmission rates were assessed at 7-, 14-, and 21-days post-infection. Vertical transmission of the virus to the progenies was also analyzed. Overall, Ae. albopictus exhibited low infection rates, with occasional dissemination and transmission events. Aedes aegypti and Cx. pipiens showed infection and occasional dissemination, but no evidence of transmission. A second non-infectious blood meal did not significantly affect infection, dissemination, or transmission rates in any species. Viral loads in bodies and legs were low and did not differ significantly between species, time points, or feeding regimens. Survival was not affected by infection or blood-feeding regime. We did not find vertical transmission of OROV to the progenies. Regardless of virus dissemination in mosquitoes, our study indicates poor vector competence of Spanish Ae. albopictus and a lack of competence in Ae. aegypti and Cx. pipiens for the circulating OROV strain. These findings suggest a low risk for local OROV establishment in Spain, although continuous surveillance and research are warranted to monitor potential vector-virus adaptation.

microbiology↗

bioRxiv2025

Integrating citizen science and field sampling into next-generation early warning systems for vector surveillance: Twenty years of municipal detections of Aedes invasive mos-quito species in Spain

The spread of invasive mosquitoes Aedes albopictus, Aedes aegypti and Aedes japonicus in Spain represents an increasing public health risk due to their capacity to transmit arboviruses such as dengue, Zika and chikungunya among others. Traditional field entomological surveillance remains essential for tracking their spread, but it faces limitations in terms of cost, scalability and labor intensity. Since 2014, the Mosquito Alert citizen science project has enabled public participation in the surveillance through the submission of geolocated images via a mobile app, which are identified using AI in combination to expert validation. While field surveillance provides high accuracy, citizen science offers low-cost, large-scale real-time data collection aligned to open data managment principles. It is particularly useful for detecting long-distance dispersal events and has contributed up to one-third of the municipal detections of invasive mosquito species since 2014. This study assesses the value of integrating both surveillance systems to capitalize on their complementary strengths while compensating weaknesses in the areas of taxonomic accuracy, scalability, spatial detection patterns, data curation and validation systems, geographic precision, interoperability and real-time output. We present the listing of municipal detections of these species from 2004 to 2024, integrating data from both sources. Spains integrated approach demonstrates a pioneering model for cost-effective, scalable vector surveillance tailored to the dynamics of invasive species and emerging epidemiological threats. Simple SummarySpain, with its diverse ecological and climatic landscapes, represents a key area for the introduction and establishment of invasive mosquito species, posing threats to public health due to their capacity to transmit human diseases. Field entomological surveillance conducted by experts remains the primary tool for tracking their spread, though it is limited by geographical scales and cost factors. Advances in smartphone technology allows citizen science strategies of data collection such as submitting mosquito photos via the Mosquito Alert app. This type of information is of a different nature from the field sampling and still needs expert interpretation, but offers significantly broader and faster geographical coverage. Two decades have passed since the first detection of the Asian tiger mosquito in Spain in 2004, and following the Mosquito Alert creation in 2014, citizen science has contributed with one-third of the discoveries of this species at the municipal level in Spain. We discuss integration of both approaches in order to harness their respective strengths while compensating their drawbacks, to develop faster and more powerful early warning surveillance systems, and also returning value to the society by empowering citizenship.

ecology↗