Biology subjects

Fontoura-Goncalves, C.

Publications and source records attributed to Fontoura-Goncalves, C..

4 recordsLinked to original sources

bioRxiv2026

Post-outbreak surveillance reveals contrasting circulation dynamics of West Nile, Usutu and Bagaza viruses in southern Portugal, 2021 - 2023

Mosquito-borne orthoflaviviruses pose a significant threat to human and animal health worldwide. In Europe, West Nile (WNV), Usutu (USUV) and Bagaza (BAGV) viruses have expanded their geographic distribution and are detected with increasing frequency. Following the emergence of BAGV in 2021, we investigated the circulation dynamics and genomic diversity of orthoflaviviruses in southern Portugal, where their epidemiology remains poorly understood. Active Orthoflavivirus surveillance was conducted in birds and mosquitoes during 2021-2023 using serological and molecular assays, complemented by viral genome sequencing and phylogenomic analyses. Viral RNA was detected in 3.5% (41/1,171) of birds, while seroneutralization assays identified an overall seroprevalence of 55.3% (503/910). WNV RNA (lineage-1, strains WMed-1.2 and WMed-1.3) was detected annually in resident birds, including Alectoris rufa, Cyanopica cooki and Garrulus glandarius (1.5%, 18/1,171), and in Culex univittatus mosquitoes (0.8%, 2/255). Together with a WNV-specific seroprevalence of 28.5% (259/910) in birds, these findings support sustained local circulation. USUV RNA (Africa 3.1 sub-lineage) was detected in A. rufa in 2021 and 2023 (0.2%, 2/1,171), but seroprevalence was low (1.3%, 8/623), consistent with intermittent circulation. BAGV RNA (genotype-2) was detected only during the 2021 outbreak in A. rufa and Emberiza calandra (1.8%, 21/1,171), although BAGV-specific antibodies (6.6%, 60/910) were detected for up to two years after the outbreak, suggesting continued exposure or low-level circulation. Overall, our findings reveal contrasting circulation dynamics of orthoflaviviruses in southern Portugal. Sustained WNV circulation implies the need to strengthen avian and human surveillance in Portugal to better assess its public health risk, while the sporadic detection of USUV and BAGV underscores the value of long-term, integrated One Health surveillance for improving early warning and preparedness for emerging mosquito-borne diseases.

genetics↗

bioRxiv2024

Usutu virus African 3.1 lineage, Portugal, 2021-2023

BackgroundUsutu virus (Orthoflavivirus usutuense, USUV), a neurotropic arthropod-borne RNA virus of the family Flaviviridae, is a zoonotic virus that has spread throughout the European continent over the last three decades, since its emergence in Italy in 1996. However, no cases of USUV have been reported in Portugal so far. Material and methodsIn the scope of an active surveillance program for Orthoflavivirus, we collected growing feather samples from 249 red-legged partridges (Alectoris rufa) hunted in southern Portugal during the 2021-2023 hunting seasons. Samples positive for USUV were subjected to whole genome sequencing and strain characterization. ResultsTwo partridges tested positive for USUV. Phylogenetic analyses of whole and partial genomes assigned the USUV strains to the African 3 lineage, specifically the African 3.1 sub-lineage. ConclusionsOur study confirms, for the first time, the circulation of USUV in wild birds in Portugal. Active surveillance of hunted partridges proved to be a useful, accessible, and cost-effective method for USUV monitoring, further supporting their value as effective sentinels for Orthoflavivirus surveillance. Given the ongoing circulation of USUV and the increasing risk of its spillover to other domestic and wild animals, and humans, additional efforts are needed to improve virus surveillance in Portugal from a One Health perspective.

microbiology↗

bioRxiv2024

Using integrated wildlife monitoring for quantifying the impact of emerging Bagaza virus in red-legged partridges in Portugal, 2012-2024

Bagaza virus, a vector-borne flavivirus that causes significant mortality in wild bird species, emerged in Portugal in September 2021. This study used integrated wildlife monitoring to quantify its impact on a natural population of red-legged partridge (Alectoris rufa) in southern Portugal. We constructed a baseline model of population dynamics prior to the outbreak (2012-2021) and used this model to predict population size in subsequent years (2022-2024). This model, which included population abundance and demographic data of red-legged partridge, as well as climatic variables, showed a strong fit to the observed data, and the difference between the predicted and observed population size in 2022 suggests a Bagaza-induced mortality rate of at least 59% (95% CI 52-66%). In addition to enabling the adaptive management of populations, our results demonstrate that integrated wildlife monitoring offers epidemiological insights for risk assessment, highlighting its role in proactive wildlife disease surveillance within the One Health framework.

ecology↗

bioRxiv2024

Dynamics of Bagaza, West Nile, and Usutu viruses in Portugal revealed by long-term serological surveillance in red-legged partridges, 2018-2022

BackgroundBagaza virus (BAGV) emerged in Portugal in 2021. BAGV and other flaviviruses such as West Nile virus (WNV) and Usutu virus (USUV) represent emerging threats in Europe, yet uncertainties persist regarding their epidemiological status in Portugal. AimThis study aimed to elucidate the epidemiological dynamics of BAGV, WNV, and USUV in Portugal using the red-legged partridge (Alectoris rufa) as a susceptible bird model species. MethodsSerum samples collected from a partridge population in Southern Portugal, between 2018 and 2022, were analysed to characterize exposure to flaviviruses through enzyme-linked immunosorbent assay (ELISA; n=468) and virus neutralization test (VNT; n=433). ResultsELISA test revealed an average seroprevalence of 58.1% for WNV and WNV-cross-reacting antibodies between 2018 and 2022, while 66.3% of individuals tested positive using VNT: 28.8% specific for WNV, 8.1% for BAGV, 2.1% for USUV and 27.2% for "undetermined flaviviruses". BAGV seroprevalence was first detected in October 2021 (8.7%), alongside an outbreak detection, peaking in November 2021 (26.3%) and persisting until October 2022 (2.3%). WNV antibodies were detected throughout all sampling periods, with the highest seroprevalence in October 2020 (44.8%). USUV seroprevalence was detected until the BAGV outbreak in 2021, peaking in October 2020 (6.9%). ConclusionLong-term serological surveillance of partridges revealed endemic circulation of WNV and sporadic circulation of BAGV and USUV in Portugal. Notably, the highest WNV seroprevalence coincided with the human WNV outbreak in southern Spain in the summer of 2020, highlighting the role of red-legged partridges in the transmission/maintenance cycle and as sentinels of flaviviruses circulation.

immunology↗