Vector-borne RADAR (Real-time Arbovirus Detection And Response)

Vector-borne RADAR looks to enhance surveillance of mosquito-borne diseases of wild birds in the UK that have wider medical and veterinary importance by adopting a One Health approach. Our first work package will increase the scope of our successful, multi-disciplinary network, which was responsible for the detection of Usutu virus in the UK in 2020, to include additional routes for sampling both bird hosts and mosquito vectors. This will follow a similar and successful paradigm that has been used in the Netherlands to detect emerging mosquito borne viruses of wild birds (www.onehealthpact.org). In essence we will co-opt bird observatories and licensed ringers in areas deemed at high-risk of virus incursion to sample migrant birds (to identify potential routes of virus incursion) and resident birds (to elucidate geographic extent and virus prevalence). At each of our designated bird sampling sites we will also set up mosquito traps to provide information on vector community composition, virus prevalence and potential transmission networks.
Our second work package will develop an early warning system for the detection of potential zoonotic viral diseases of wild birds in the UK. Two existing and independent citizen science data schemes (the British Trust for Ornithology's [BTO] Garden BirdWatch, and the Garden Wildlife Health [GWH] project) will be co-opted to identify clusters of disease incident reports which correlate with a reduction in wild bird reporting rates, as a proxy to indicate areas of virus circulation and assess near real-time impact. This approach has been shown to be successful, by our consortium, in retrospectively identifying patterns of Blackbird mortality and declines in reporting rates caused by the 2020 Usutu virus outbreak in the UK.
Our third work package will be conducted in collaboration with citizen scientists who participate in the BTO Garden BirdWatch. We will undertake a survey aiming to understand fine-scale Blackbird movements and habitat use in UK gardens. Data generated will provide detail on specific habitat use and identify potential virus transmission risks in relation to habitat features of gardens that are also likely to encourage higher mosquito populations (e.g. areas of stagnant water). Alongside this we will establish Blackbird trapping sites in London and the south-east, where licensed ringers will aim to catch birds in mist nets and colour-ring (so they can be identified from a distance without the need for further trapping) individual Blackbirds in order to quantify survival rates through time. Ringers involved in the scheme will also be trained to deploy mosquito traps and identify mosquitoes to provide evidence to link vector abundance and disease prevalence directly to wild bird survival.
The data generated from this research proposal will improve our understanding of how exotic mosquito-borne viruses emerge and persist in temperate areas while also feeding directly into government policy & risk assessments on zoonotic diseases, public health messages and mosquito control strategies. Through engagement with citizen scientists, wildlife rehabilitators, zoological collections, and animal welfare and conservation NGOs, we will also raise awareness of implications for animal health and impacts on biodiversity.

Vector-Borne RADAR will create a real-time monitoring scheme to detect emerging mosquito-borne diseases of birds. We propose to collect contour feathers and buccal swabs from migrant and resident birds at a network of sampling sites in southern England, along with mosquito trapping to understand the role of local vector species in onward transmission. A trained veterinarian will also attend monthly to take cloacal and sera samples from target birds caught on that day under Home Office ASPA License, to detect viral- and seroprevalence, thus elucidating incursion pathways and transmission networks. All tissue, swab, feather and mosquito samples will be taken to Biosecurity level 3 laboratories to have total RNA extracted before screening using two avian flavivirus specific qRT-PCRs (West Nile [WNV] and Usutu virus [USUV]). Any positive detection will be sent for Sanger or Illumina sequencing to confirm identification and for Bayesian phylogenetic and phylogeographic analysis. Positive RNA aliquots will also be cultured in Vero cells to isolate virus. Sera samples will be screened using a flavivirus specific Enzyme-Linked immunosorbent assay (ELISA). To check for antibody specificity against WNV and USUV any ELISA positive sera will be used in a plaque reduction neutralisation test (PRNT) using Vero cells and live virus. Positive tissue samples will also be sent for immunohistochemical and Haematoxylin & Eosin analysis to visualise in situ viral tropism. We will also establish 10 Blackbird trapping sites in London and the south-east where licensed ringers will aim to trap and colour-ring (obviating the need for further trapping) individual Blackbirds in order to quantify survival rates, as this species is highly susceptible to USUV infection. Finally, we will create an early warning system for disease outbreaks in UK wild birds by identifying contemporaneous increases in disease reports combined with a reduction in weekly reporting count.