Biology subjects

Vaux, A. G. C.

Publications and source records attributed to Vaux, A. G. C..

4 recordsLinked to original sources

bioRxiv2026

A faster incubation explains Usutu leading West Nile in temperate Europe

Usutu virus (USUV) is a mosquito-borne flavivirus that has recently expanded northwards in Europe and become endemic in the UK. USUV emergence often precedes the closely related West Nile virus (WNV), potentially reflecting differences in epidemiological parameters. One key parameter is the extrinsic incubation period (EIP), the time taken for a mosquito to become infectious after a blood meal. Here we present the first quantitative estimate of the temperature dependent EIP for USUV in the vector Culex pipiens molestus. We were able to quantify the shortening of the USUV EIP from 68.06 days (95% CrI: 38.62 to 141.04) at 17 {degrees}C to 12.35 days (95% CrI: 8.10 to 17.09) at 25{degrees}C. This was achieved by re-analysing laboratory data with a bespoke Bayesian model that accounted for important features of the experimental design. Under UK summer temperatures, the median EIP of USUV is 37.75% (95% CrI: 3.38 to 55.68) shorter than that of WNV, and the potential transmission season of USUV is both longer and geographically more extensive. Under RCP8.5 climate projections, WNV transmission suitability could match or exceed current USUV levels between 2055 and 2065, highlighting the future threat to the UK from emerging mosquito borne pathogens. Our findings support USUV as a precursor for WNV in Europe and provide a robust characterisation of a key epidemiological parameter of USUV, enabling accurate modelling of its transmission dynamics.

ecology↗

bioRxiv2026

Ecology of mosquitoes in Scottish wetlands and confirmation of Culex molestus and hybrids in Scotland

BackgroundThe recent spread of mosquito-borne pathogens and their vectors within Europe highlights the impact of climate change on vector-borne disease (VBD) distributions. Mosquito surveillance has been implemented in many European countries to monitor expansion of vector populations and VBDs, but ability to predict disease risk is constrained by geographic data gaps, particularly in northern areas. In the United Kingdom, wetland mosquito surveillance has been conducted extensively in England, with a knowledge deficit for Scotland. Here, we addressed this gap through a nationwide survey of mosquitoes at Scottish wetlands, with aims of 1) confirming the geographic distribution and environmental drivers of mosquito occurrence and abundance, and 2) identifying the presence of vector species of epidemiological concern, including the Culex pipiens molestus biotype, an important vector of emerging VBDs in mainland Europe. MethodsMonthly mosquito sampling was conducted between June and October 2023 at 22 sites across Scotland comprising six wetland types: coastal saltmarsh, wet grassland, wet woodland, reedbeds, ponds and blanket bog. Adult and larval populations were sampled using Biogents BG-Pro traps and larval dipping respectively. Microclimatic and hydrological variables were recorded at collection sites and used in generalised linear mixed models to identify predictors of mosquito presence and abundance. Results1951 adults (17 species/ groups) and 860 larvae (six species/ groups) were collected from wetlands over 183 and 164 sampling events respectively. Mosquitoes were widely distributed across the Scottish mainland including up to the northern coast, being found at all but one site. Several potential vector species including Culex pipiens s.l. and Anopheles claviger were common. Amongst the adult Culex pipiens s.l. specimens, approximately 8% were Culex pipiens biotype molestus or hybrid forms. Total mosquito abundance and that of key vector species were positively associated with temperature and rainfall. ConclusionsWe report the widespread distribution of mosquitoes in wetlands throughout Scotland, including potential vector species previously unconfirmed in Scotland. Predicted associations between mosquito abundance, rainfall and temperature indicate that climate change could favour mosquito populations in Scotland. Our results provide the first comprehensive description of mosquito ecology in Scotland, as required to update assessment of VBD risk under climate change.

ecology↗

bioRxiv2025

Detection of West Nile Virus via Retrospective Mosquito Arbovirus Surveillance in the United Kingdom

In March 2025, as part of on-going enhanced surveillance for mosquito-borne Orthoflaviviruses, West Nile virus (WNV) RNA was detected in two pools of female Aedes vexans collected in July 2023 in Nottinghamshire, England. Viral RNA detection was achieved via reverse transcription-qPCR. Sequencing and subsequent phylogenetic analysis of a 402 bp fragment indicated that the detections clustered with WNV lineage 1a. The exact origin of this virus remains unclear, but this finding indicates a historic WNV presence in the United Kingdom (UK). Surveillance has not provided evidence of further viral transmission to date.

molecular biology↗

bioRxiv2024

Transovarial transmission in field caught mosquitoes identifies a mechanism for the establishment of Usutu virus in a temperate country

Usutu virus (USUV) is an emerging zoonotic flavivirus in Europe, and the first zoonotic mosquito-borne virus to be confirmed in animal hosts in the United Kingdom (UK). Phylogenetic analysis of USUV in the three years following its initial detection in 2020 indicated that the virus is overwintering in the UK. In 2023, USUV was identified outside Greater London for the first time. Therefore, USUV should now be considered endemic within southeast England. Surveillance of avian hosts and mosquito vectors has been insufficient to elucidate the mechanism by which USUV has persisted through temperate winters. It is likely that mosquitoes play a significant role in facilitating the establishment of USUV in temperate areas, as is the case for related mosquito-borne viruses. Here we undertake enhanced targeted vector surveillance at the index site to investigate the role of mosquitoes in facilitating USUV establishment in the UK. Between 2021 and 2024 inclusive, we detected USUV in host-seeking adult female Culex pipiens s.l. (n = 8/554 pools), a key vector of the virus in Europe. During 2023, enhanced surveillance detected transovarial transmission of USUV in wild Cx. pipiens s.l. (n = 1/202 pools), by screening adults following captive rearing of mosquito larvae collected from the field. This is, to our knowledge, the first description of vertical transmission of USUV in an arthropod vector. Consequently, transovarial transmission should be considered a viable mechanism for the persistence of USUV in temperate areas. Our results highlight the importance of undertaking detailed vector surveillance, across life stages, to inform the epidemiology of vector-borne viruses.

microbiology↗