Biology subjects

Goncalves, D.

Publications and source records attributed to Goncalves, D..

11 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↗

bioRxiv2026

Diet and breeding productivity in European Shag (Gulosus aristotelis): insights from two Portuguese colonies

Climate change and anthropogenic pressures are reshaping marine food webs, altering prey availability and affecting top predators. The European Shag (Gulosus aristotelis), a coastal demersal seabird, provides a valuable model for examining environmentally mediated dietary variation, given its trophic plasticity and capacity to adjust prey use according to local availability, while also allowing assessment of potential demographic consequences. This study investigated spatial and temporal variation in diet at two Portuguese colonies (Berlengas and Arrabida) between 2016 and 2024 and assessed long-term reproductive productivity at Berlengas. A total of 468 regurgitated pellets were analysed, and diet composition was quantified using the Index of Relative Importance (IRI). Generalised additive models were applied to assess environmental, spatial, and period-specific effects on diet composition, while reproductive productivity was modelled in relation to prey biomass. Diet variation was primarily explained by environmental predictors, including sea surface temperature, chlorophyll-a concentration, and zooplankton, whereas year per se had no significant effect, indicating environmentally mediated bottom-up effects. Spatial differences between colonies reflected contrasting prey field structures, and period-specific patterns suggested increased specialisation during breeding. Higher biomass of sandeels (Ammodytidae) was positively associated with reproductive output, whereas shifts toward lower-energy prey were associated with reduced productivity. These findings demonstrate that environmentally driven dietary change has measurable demographic consequences, underscoring the importance of bottom-up processes in shaping seabird population dynamics and informing conservation strategies under ongoing climate change.

ecology↗

bioRxiv2026

Isolation and characterization of Bagaza virus: insights into host adaptability and zoonotic potential.

Bagaza virus (BAGV) is an emerging orthoflavivirus that primarily infects wild birds, but its ability to infect other hosts remains poorly understood. We isolated BAGV RNA from the brain of a dead red-legged partridge and evaluated viral adaptation and replication kinetics in avian, mosquito, mammalian, and human cell lines. BAGV replicated efficiently in monkey, mosquito, duck, and selected human cell lines (HEK-293T and Huh7.5), whereas replication was limited in other human, hamster, and chicken fibroblast cell lines, indicating variable cellular susceptibility. These differences may reflect host-specific adaptation or distinct innate immune responses. Viral RNA replication complexes localized to the cytoplasm, as shown by immunocytochemical detection of dsRNA. Ribavirin treatment significantly reduced viral titers and RNA levels, demonstrating antiviral sensitivity. Together, these findings provide new insights into BAGV biology, host adaptability, and potential zoonotic risk, and support the development of antiviral strategies and improved epidemiological surveillance within a One Health framework.

microbiology↗

bioRxiv2025

Characterization of a COQ8A-ataxia mouse model with E548K single-site mutation: distinct and comparable findings relative to a loss-of-function mutation

COQ8A-ataxia, also known as autosomal recessive cerebellar ataxia type 2 (ARCA2), is a rare mitochondrial disorder caused by biallelic mutations in COQ8A, a gene encoding for a mitochondrial protein critical for coenzyme Q (CoQ) biosynthesis. Although there is no clear genotype-phenotype correlation in patients, loss-of function variants generally produce a cerebellar-restricted phenotype, while missense mutations are more frequently associated with multisystemic symptoms. The COQ8AE551K variant has been reported at the homozygous state in individuals with early-onset disease and widespread systemic involvement. This study aimed to characterize the new Coq8aE548K knocking mouse model, equivalent to the human E551K variant, and compare its phenotype to the complete Coq8a-/- knockout mouse. Based on human data and preliminary data in the zebrafish, we hypothesized that the Coq8aE548K knocking would present a more pronounced phenotype than the constitutive knockout. Contrary to our initial hypothesis, mice homozygous for the Coq8aE548K allele exhibited no significant motor or cognitive impairments, nor muscle phenotype. Biochemically, the knocking Coq8aE548K mutation led to variable instability of the COQ8AE548K protein and reduced expression of proteins in the CoQ biosynthesis pathway, such as COQ5 and COQ7 in both cerebellum and muscle, similarly to the constitutive knockout. Despite this, mitochondrial function and tissue architecture remained intact, suggesting preserved cellular resilience. These findings highlight the complexity of genotype-phenotype correlations in COQ8A-related ataxia and provides a tool for investigating sub-threshold mitochondrial dysfunction.

cell biology↗

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

Exploring tropical freshwater soundscapes in Southeast Asia: insights into auditory sensory adaptation of wild Siamese fighting fish Betta splendens

While soundscapes shape the structure and function of auditory systems over evolutionary timescales, there is limited information regarding the adaptation of wild fish populations to their natural acoustic environments. This is particularly relevant for freshwater ecosystems, which are extremely diverse and face escalating pressures from human activities and associated noise pollution. The Siamese fighting fish Betta splendens is one of the most important cultured species in the global ornamental fish market and is increasingly recognized as a model organism for genetics and behavioural studies. This air-breathing species (Anabantoidei), characterized by the presence of a suprabranchial labyrinth organ, is native to Southeast Asia and inhabits low flow freshwater ecosystems that are increasingly threatened due to habitat destruction and pollution. We characterized the underwater soundscape, along with various ecological parameters, across five marshland habitats of B. splendens, from lentic waterbodies to small canals near a lake in Chiang Rai province (Thailand). All habitats exhibited common traits of low dissolved oxygen and dense herbaceous vegetation. Soundscapes were relatively quiet with Sound Pressure Level (SPL) around 102-105 dB re 1 {micro}Pa and most spectral energy below 1000 Hz. Sound recordings captured diverse biological sounds, including potential fish vocalizations, but primarily insect sounds. Based on Auditory Evoked Potential (AEP) recordings, we identified sex-specific differences and a best hearing range within 100-400 Hz. This low-frequency tuning highlights the potential susceptibility of B. splendens to anthropogenic noise activities. This study provides first characterization of the auditory sensitivity and natural soundscape of B. splendens, establishing an important ground for future hearing research in this species. The information provided on the auditory sensory adaptation of B. splendens emphasizes the importance of preserving quiet soundscapes from lentic freshwater ecosystems.

zoology↗

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↗

bioRxiv2023

Drivers of species knowledge across the Tree of Life

Knowledge of biodiversity is unevenly distributed across the Tree of Life. In the long run, such disparity in awareness unbalances our understanding of life on Earth, influencing policy decisions and the allocation of research and conservation funding. We investigated how humans accumulate knowledge of biodiversity by searching for consistent relationships between scientific (number of publications) and societal (number of views in Wikipedia) interest, and species-level morphological, ecological and socio-cultural factors. Across a random selection of 3,019 species spanning 29 Phyla/Divisions, we show that socio-cultural factors are the most important correlates of scientific and societal interest in biodiversity, including the fact that a species is useful or harmful to humans, has a common name and is listed in the IUCN Red List. Furthermore, large-bodied, broadly distributed and taxonomically unique species receive more scientific and societal attention, whereas colorfulness and phylogenetic proximity to humans correlates exclusively with societal attention. These results highlight a favoritism towards limited branches of the Tree of Life, and that scientific and societal priorities in biodiversity research broadly align. This suggests that we may be missing out on key species in our research and conservation agenda simply because they are not on our cultural radar.

ecology↗

bioRxiv2022

Hormone levels increase in response to video playback in the Siamese fighting fish

The mechanisms of action of hormones regulating aggression in fish remain poorly understood. One possibly confounding variable is the lack of standardization in the type of stimuli used to elicit aggression. The presentation of controlled stimuli in videos, a.k.a. video playback, can provide better control of the fight components. However, this technique has produced conflicting results in animal behaviour studies and needs to be carefully validated. Here, the response of male Betta splendens to a matched for size conspecific fighting behind a one-way mirror presented live or through video playback was compared. Despite their non-interactive nature, both stimuli elicited a strong aggressive response by focal fish, which started with stereotypical threat displays and progressed to overt attacks. Overall, the frequency and duration of aggressive behaviours and swimming activity were similar towards live and video stimuli. Post-fight plasma levels of the androgen 11-ketotestosterone were elevated as compared to controls, regardless of the type of stimuli. Cortisol also increased in response to the video images, as previously described for interactive live fights in this species. The study shows for the first time in a fish a robust endocrine response to video stimuli and supports the use of this technique for researching aggressive behaviour in B. splendens.

animal behavior and cognition↗

bioRxiv2021

Bagaza virus in wild birds, Portugal, 2021

Bagaza virus (BAGV) emerged in Spain, in 2010. Since then, BAGV was not reported in other European countries until September 2021, when BAGV was diagnosed by molecular methods in one corn bunting and several red-legged partridges, after abnormal mortality in Southern Portugal. Sequencing revealed high similarity with strains reported previously.

pathology↗