Search Results (645)

This study investigates the seasonal dynamics of energy balance, evapotranspiration (ET), and Net Ecosystem Production (NEP) in the Dengkou desert ecosystem of Inner Mongolia, China. Using eddy covariance and meteorological data from 2019 to 2022, the research focuses on understanding how these processes interact in one of the world’s most water-limited environments. This arid research area received an average of 109.35 mm per annum precipitation over the studied period, classifying the region as a typical arid ecosystem. Seasonal patterns were observed in daily air temperature, with extremes ranging from −20.6 °C to 29.6 °C. Temporal variations in sensible heat flux (H), latent heat flux (LE), and net radiation (Rn) peaked during summer season. The average ground heat flux (G) was mostly positive throughout the observation period, indicating heat transmission from atmosphere to soil, but showed negative values during the winter season. The energy balance ratio for the studied period was in the range of 0.61 to 0.80, indicating challenges in achieving energy closure and ecological shifts. ET exhibited two annual peaks influenced by vegetation growth and climate change, with annual ET exceeding annual precipitation, except in 2021. Net ecosystem production (NEP) from 2019 to 2020 revealed that the Dengkou desert were a net source of carbon, indicating the carbon loss from the ecosystem. In 2021, the Dengkou ecosystem shifted to become a net carbon sink, effectively sequestrating carbon. However, this was sharply reversed in 2022, resulting in a significant net release of carbon. The study findings highlight the complex interactions between energy balance components, ET, and NEP in desert ecosystems, providing insights into sustainable water management and carbon neutrality strategies in arid regions under climate change effect. Full article

Northern Thailand frequently suffers from severe PM2.5 air pollution, especially during the dry season, due to agricultural burning, local emissions, and transboundary haze. Understanding how pollution moves across regions and identifying source–receptor relationships are critical for effective air quality management. This study investigated the spatial and temporal dynamics of PM2.5 in northern Thailand. Specifically, it explored how pollution at one monitoring station influenced concentrations at others and revealed the seasonal structure of PM2.5 transmission using network-based analysis. We developed a Python-based framework to analyze daily PM2.5 data from 2022 to 2023, selecting nine representative stations across eight provinces based on spatial clustering and shape-based criteria. Delaunay triangulation was used to define spatial connections among stations, capturing the region’s irregular geography. Cross-correlation and Granger causality were applied to identify time-lagged relationships between stations for each season. Trophic coherence analysis was used to evaluate the hierarchical structure and seasonal stability of the resulting networks. The analysis revealed seasonal patterns of PM2.5 transmission, with certain stations, particularly in Chiang Mai and Lampang, consistently acting as source nodes. Provinces such as Phayao and Phrae were frequently identified as receptors, especially during the winter and rainy seasons. Trophic coherence varied by season, with the winter network showing the highest coherence, indicating a more hierarchical but less stable structure. The rainy season exhibited the lowest coherence, reflecting greater structural stability. PM2.5 spreads through structured, seasonal pathways in northern Thailand. Network patterns vary significantly across seasons, highlighting the need for adaptive air quality strategies. This framework can help identify influential monitoring stations for early warning and support more targeted, season-specific air quality management strategies in northern Thailand. Full article

Background: Despite decades of high childhood vaccination coverage, pertussis has re-emerged in the Autonomous Province of Vojvodina (AP Vojvodina), Serbia. We aimed to describe the temporal, seasonal, and age-specific patterns of pertussis in AP Vojvodina and to analyze trends by vaccination status in order to highlight changes in epidemiology and potential gaps in vaccine-induced protection. Methods: We retrospectively analyzed 2796 pertussis cases reported between January 1997 and December 2024, examining temporal, seasonal, and age-specific trends, stratifying by vaccination status across four consecutive periods (1997–2003, 2004–2010, 2011–2017, and 2018–2024). Results: Throughout the 28-year period, after low and sporadic cases in the pre-2012 period, a dramatic rise was observed in 2014, 2017, and 2018, culminating in the highest annual number of reported cases in 2024 (1011 cases). Throughout this period, primary vaccination coverage with the DTwP/DTaP three-dose series ranged between 91% and 98%, while first booster coverage gradually declined from 98% in the early 2000s to 83% in 2024. Regarding seasonality, a sharp increase in cases began in 2012, peaking in November 2023 (>350 cases) and early 2024 (312 in January, 268 in February), with a seasonal shift from summer peaks in the 2011–2017 period to higher incidence rates during colder months more recently. Adolescents aged 10–14 years had the highest cumulative incidence (1149.4/100,000), followed by infants under 12 months (978.5/100,000), despite the latter representing fewer absolute cases. The proportion of pertussis in fully vaccinated individuals rose from 6.3% (1997–2003) to 49.7% (2018–2024). Conclusions: These findings suggest that booster immunization in adolescence and routine maternal vaccination during pregnancy could reduce transmission, particularly to infants. Enhanced surveillance and updated immunization policies are critical to mitigating future pertussis outbreaks. Full article

Yeasts possess a range of environmental adaptations that allow them to colonize soil and sand. They can circulate seasonally between different components of lake ecosystems, including beach sand, water, and the coastal phyllosphere. The accumulation of people on beaches promotes the development and transmission of yeasts, posing an increasing sanitary and epidemiological risk. The aim of this study was to determine the species and quantitative composition of potentially pathogenic and pathogenic yeasts for humans present in the sand of supervised and unsupervised beaches along the shores of lakes in the city of Olsztyn (northeastern Poland). The study material consisted of sand samples collected during two summer seasons (2019; 2020) from 12 research sites on sandy beaches of four lakes located within the administrative boundaries of Olsztyn. Standard isolation and identification methods used in diagnostic mycological laboratories were applied and are described in detail in the following sections of this study. A total of 259 yeast isolates (264, counting species in two-species isolates separately) belonging to 62 species representing 47 genera were obtained during the study. Among all the isolates, five were identified as mixed (two species from a single colony). Eight isolated species were classified into biosafety level 2 (BSL-2) and risk group 2 (RG-2). The highest average number of viable yeast cells was found in sand samples collected in July 2019 (5.56 × 10² CFU/g), August, and September 2020 (1.03 × 10³ CFU/g and 1.94 × 10³ CFU/g, respectively). The lowest concentrations were in samples collected in April, September, and October 2019, and October 2020 (1.48 × 10² CFU/g, 1.47 × 10² CFU/g, 1.40 × 10² CFU/g, and 1.40 × 10² CFU/g, respectively). The results indicate sand contamination with yeasts that may pose etiological factors for human mycoses. In light of these findings, continuous sanitary-epidemiological monitoring of beach sand and further studies on its mycological cleanliness are warranted, along with actions leading to appropriate legal regulations. Full article

Influenza A virus (IAV) poses a significant threat to animal and public health due to its wide host range and potential for interspecies transmission. This study aimed to conduct a comprehensive survey of IAV in a wide range of wildlife in the Orinoco flooded savannas of Colombia, a region of high biodiversity and a strategic location for monitoring viral transmission. Sampling was conducted during both dry and rainy seasons in two localities. ELISA and qPCR targeted 2028 individuals from 173 bird, mammal, and reptile species, 124 of them without previously published reports. There were positive results for 54 species, with 34 representing first-time world reports. Of the qPCR, 13.4% were positive from birds, and 2.9% were from mammals. Seropositivity was identified in 5.7% of birds, 2.7% of mammals, and 1.3% of reptiles. These findings underscore the potential role of these diverse species as reservoirs or incidental hosts in the transmission cycle of IAV, emphasizing the need for expanded research on less-studied taxa and their ecological interactions. The results also contribute to our understanding of the epidemiology of IAV in the Neotropics and can inform future surveillance and mitigation strategies. Full article

White-tailed deer (Odocoileus virginianus) in the wild and on cervid farms have drawn the attention of state wildlife agencies and animal health agencies as Chronic Wasting Disease (CWD) has spread across North America. Deer farm regulations have been implemented to reduce direct contact between wild and farmed cervids; however, evidence suggests that indirect contact to infectious prions passed through the alimentary tracts of scavengers may be an important transmission pathway. The objective of this study was to characterize mammalian scavenger and wild deer activities associated with deer farms and link these activities with site-specific spatial covariates utilizing a network of camera traps, mounted to farm perimeter fences. We monitored each of 14 farms in Minnesota, Wisconsin, and Pennsylvania for two weeks during the summer, with a subset of farms also monitored in the winter and fall. Across all sites and seasons, we captured 749 observations of wildlife. In total, nine species were captured, with wild white-tailed deer accounting for over three quarters of observations. Despite the large number of wild deer observed, we found that interactions between wild and farmed deer at the fence line were infrequent (six direct contacts observed). In contrast, mammalian scavengers were frequently observed inside and outside of the fence. Supplementary cameras placed on deer feeders revealed higher observation rates of scavengers than those placed along fence lines, highlighting the potential for transmission of CWD through indirect contact via scavenger excreta. To evaluate associations between the number of observations of focal species with land-cover characteristics, two mixed-effects regression models were fitted, one model for scavengers and one for wild deer. Contrary to our hypothesis, landscape context did not have a strong impact on wildlife visitation. This suggests that farm location is less important than management practices, highlighting the need for future research into how farming practices impact rates of wildlife visitation onto cervid farms. Full article

Staphylococcus aureus frequently causes intramammary infections in dairy cows (bovine mastitis), which impair animal welfare, milk yield, and food safety. This study determined the prevalence and genetic diversity of S. aureus in bulk tank milk (BTM) samples from community-based Alpine dairy pastures in Tyrol, a major milk-producing region in Austria. Throughout the 2023 Alpine season (May–September), 60.3% (94/156) of BTM samples tested positive for S. aureus at least once over the course of up to four samplings. A total of 140 isolates collected from the 94 S. aureus-positive community-based Alpine dairy pastures revealed 33 distinct spa types, with t2953 (n = 33), t529 (n = 12), t267 (n = 11), and t024 (n = 10) being the most common. Selected isolates representing the different spa types were characterised by DNA microarray-based genotyping, multi-locus sequence typing (MLST), and antimicrobial susceptibility testing. Isolates with spa types associated with bovine-adapted CC8 (CC8bov/GTB) were identified as the most common subtype, being detected in BTM samples from 35.3% (55/156) of the pastures. This emphasises the high prevalence of this subtype in dairy herds across European Alpine countries. Other common bovine-associated subtypes were also detected, including CC97, CC151, and CC479. While antimicrobial resistance was rare, enterotoxin-producing genes were detected in all CC8bov-associated spa types. Overall, these findings underscore the importance of rigorous hygiene practices in dairy farming, particularly in community-based Alpine dairy pastures, where the risk of transmission is particularly high. It also emphasises the need for continued surveillance and subtyping to improve animal health, ensure food safety, and promote sustainable milk production. Full article

Due to the potential role of Auchenorrhyncha in the transmission of the bacterium Xylella fastidiosa in a wide variety of cultivations, during recent years in Europe, many studies have focused on species composition, abundance and seasonal appearance of Auchenorrhyncha. However, females and nymphs are difficult to identify, as species-level identification relies primarily on male genitalia morphology. Sampling was conducted over four years in olive fields in Lesvos Island, in the Northeast Aegean, Greece, using sweep nets and Malaise traps. Both adults and nymphs were collected, with males identified to species level, while females and nymphs were separated on different morphotypes. Representatives from each morphotype and identified adults were sequenced using the mitochondrial cytochrome oxidase subunit I (COI) gene. Using a classical morphological approach, 58 species were identified to species level, and using DNA barcoding, nymph morphotypes and females were successfully identified within the families Cicadellidae, Aphrophoridae, Delphacidae and Issidae. A phylogenetic tree was generated, clustering nymphs together with the corresponding adults. Our results demonstrate the utility of combining morphological and molecular methods for accurate species identification and highlight the importance of enriching online databases with additional species records. Full article

Emerging infectious diseases such as chytridiomycosis and ranavirosis, caused by Batrachochytrium dendrobatidis (Bd) and ranavirus (RV), respectively, are major contributors to global amphibian declines. Despite their significance, comprehensive data on the spatial epidemiology of these pathogens in South Korea remain limited. This study aimed to assess the nationwide co-occurrence and prevalence of Bd and RV across four anuran species in five administrative regions. Infection rates were analyzed in relation to host species, sex, and life history stage. Results indicated distinct prevalence patterns driven by ecological traits. Bd was predominantly detected in mountainous and coastal habitats, whereas RV was more common in flat inland areas. Both pathogens exhibited peak occurrence in central regions, likely reflecting seasonal transmission dynamics rather than stable endemic hotspots. The observed spatial heterogeneity appears to be influenced by pathogen-specific thermal tolerance and host ecology. These findings underscore the importance of understanding host–pathogen–environment interactions for effective disease surveillance and management. Continuous monitoring and integrative ecological approaches are essential to mitigate pathogen-induced biodiversity loss and to inform amphibian conservation strategies in East Asia. Full article

Humpback whales (Megaptera novaeangliae) are well known for their complex acoustic communication, which plays a critical role in social interactions and reproduction. Understanding the variability in humpback whale songs is crucial to deciphering their communication strategies and the factors that influence these changes, which may affect reproductive success and population dynamics. While most studies of humpback whale song behavior have focused on annual variation, intra-seasonal changes remain underexplored. This study investigates intra-seasonal song variation in the Colombian Pacific humpback whale population, a unique and diverse breeding stock. We analyzed 37 h of recordings collected during two distinct periods of the 2019 breeding season (July and August–September) in the northern Colombian Pacific. Song repertoires were compared between periods, and the acoustic structure of a common song unit (Unit1) was analyzed using spectrographic cross-correlation. Results revealed a decrease in repertoire diversity over the course of the season, along with an increase in the song rate and the acoustic consistency of Unit1 during the second period. These findings highlight the dynamic nature of humpback whale song production and suggest potential influences of social learning and hormonal modulation. Such insights may be useful for the conservation and monitoring of humpback whale populations in breeding areas. Full article

Background/Objectives: Respiratory syncytial virus (RSV) is a leading cause of respiratory infections across all age groups, with the greatest burden observed in young children and older adults. The COVID-19 pandemic significantly disrupted RSV circulation, resulting in an immunity gap and altered transmission dynamics. This study aimed to assess the seroprevalence of anti-RSV IgG antibodies in the Polish population during the 2023/2024 epidemic season. To our knowledge, this is the first study to characterize RSV seroprevalence at the population level in Poland. Methods: A total of 700 serum samples from individuals across different age groups were analyzed using a commercial assay to detect anti-RSV IgG antibodies. Seroprevalence and antibody levels, expressed as the index of positivity (IP), were examined by age and sex. Results: The overall seroprevalence of anti-RSV IgG antibodies was 91.4%. Antibody positivity increased markedly from 35.5% in infants aged 0–1 years to over 90% in children aged 4–5 years, reaching nearly universal levels in older age groups, including 99.1% in adults aged ≥60 years. Median IP values also rose with age, peaking in individuals aged ≥60 years. No significant differences in seroprevalence were observed between sexes, though older men showed slightly higher median IP values, potentially reflecting greater cumulative RSV exposure. Conclusions: This study provides key insights into the post-pandemic landscape of RSV immunity in Poland. The high seroprevalence across most age groups underscores widespread prior exposure, while the lower rates in infants highlight a continued vulnerability. These findings support the development and implementation of targeted immunization strategies, particularly for infants and older adults. Full article

(1) Background: As a prominent zoonotic parasitic disease, fascioliasis threatens the sustainable development of animal husbandry and public health. Current research focuses mainly on individual species (parasite or intermediate host), neglecting systematic evaluation of the transmission chain and exposure risks to animal husbandry. Thus, comprehensive studies are urgently needed, especially in the ecologically fragile alpine region of the Qinghai-Tibet Plateau; (2) Methods: Distribution data of Radix spp. and Fasciola hepatica in the Qinghai-Tibet Plateau and adjacent areas were gathered to establish a potential distribution model, which was overlaid on a map of livestock farming in the region; (3) Results: The key environmental factors influencing Radix spp. distribution were temperature seasonality (21.4%), elevation (16.4%), and mean temperature of the driest quarter (14.7%). For F. hepatica, the main factors were elevation (41.3%), human footprint index (30.5%), and Precipitation of the driest month (12.1%), with all AUC values exceeding 0.9. Both species exhibited extensive suitable habitats in Qinghai and Tibet, with higher F. hepatica transmission risk in Qinghai than Tibet; (4) Conclusions: The significant transmission risk and its impacts on the livestock industry in the Qinghai-Tibet Plateau highlight the need for proactive prevention and control measures. This study provides a scientific foundation for targeted alpine diseases control, establishes an interdisciplinary risk assessment framework, fills gaps in high-altitude eco-epidemiology, and offers insights for ecological conservation of the plateau. Full article

In the African Sahel, fonio (Digitaria sp.) is a cereal crop that alleviates mid-season hunger before other main crops are harvested. As fonio is valued for its ability to grow under low nutrient and drought conditions, it was hypothesized that it may contain endophytic bacteria that can tolerate such extreme stress. White fonio seeds were obtained from a dry environment (Mali) and a moderate rainfall environment (Guinea). Plants were grown indoors on field soil mixed with sand to mimic Sahelian soils, grown at 30 °C, and exposed to drought, optimal water, and low nitrogen stress conditions. In total, 73 cultured bacteria were classified using full-length 16S rRNA sequencing followed by searching three 16S reference databases. Selected strains were tested in vitro for tolerance to relevant abiotic stresses. Including nine isolates from seeds, the candidate root/shoot endophytes spanned 27 genera and 18–39 top-match species. Several well-known nitrogen-fixing bacteria were cultured, including Ensifer. Leaves were dominated by Bacilli (spore-formers known to withstand dry conditions). There were five root isolates of Variovorax. Leifsonia was isolated from the leaves and showed 100% sequence identity with seed isolates, suggestive of transmission from seed to shoot. In vitro experiments showed that seed isolates, including Leifsonia, survived diverse abiotic stresses relevant to the Sahel. Combined, these results suggest that white fonio hosts stress-tolerant microbiota, and points to Leifsonia as a candidate seed-to-plant transmitted endophyte, pending confirmation by future whole genome sequencing. This microbial collection serves as a starting point for long-term experiments to understand stress tolerance in this under-studied crop. Full article

Tick-borne viruses (TBVs), notably Orthonairovirus haemorrhagiae (Crimean–Congo hemorrhagic fever virus, CCHFV), are emerging global health threats intensified by climate change. Rising temperatures and altered precipitation patterns are expanding the habitats of key tick vectors, increasing their survival and reproductive success. The African continent is characterized by many different climatic zones, and climatic shifts have increased or changed CCHFV transmission patterns, becoming greater risk to humans and livestock. Beyond Africa, CCHFV spread in Europe, the Middle East, and Asia and has been facilitated by factors such as livestock movement, deforestation, and migratory birds. Climate-driven shifts in tick seasonality, behavior, and vector competence may further enhance viral transmission. Addressing these challenges requires integrated responses, including enhanced surveillance, predictive modeling, and climate-adaptive vector control strategies. A One Health approach—linking environmental, animal, and human health domains—is essential. Innovative strategies such as anti-tick vaccines and sustainable vector control methods offer promise in reducing the burden of these diseases. Proactive, collaborative efforts at regional and international levels are crucial in tackling this growing public health challenge. Full article

Dengue fever remains a major global health threat, and mathematical models are crucial for predicting its spread and evaluating control strategies. This study introduces a highly flexible dengue transmission model using a novel piecewise fractional derivative framework, which can capture abrupt changes in epidemic dynamics, such as those caused by public health interventions or seasonal shifts. We conduct a rigorous comparative analysis of four widely used but distinct mechanisms of disease transmission (incidence rates): Harmonic Mean, Holling Type II, Beddington–DeAngelis, and Crowley–Martin. The model’s well-posedness is established, and the basic reproduction number (${\Re }_0$) is derived for each incidence function. Our central finding is that the choice of this mathematical mechanism critically alters predictions. For example, models that account for behavioral changes (Beddington–DeAngelis, Crowley–Martin) identify different key drivers of transmission compared to simpler models. Sensitivity analysis reveals that vector mortality is the most influential control parameter in these more realistic models. These results underscore that accurately representing transmission behavior is essential for reliable epidemic forecasting and for designing effective, targeted intervention strategies. Full article