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Spotted fevers are diseases caused by bacterial agents belonging to the spotted-fever (SF) group of the genus Rickettsia. The first documented case of SF in Pernambuco State, Northeast Brazil, was reported here. Also, it is the first case described of fatal SF in Northeast region of Brazil. The patient was a resident of Arcoverde municipality and the probable site of infection lies in Sertania municipality, both in Pernambuco State, a semi-arid region of Brazil. The patient had not visited other areas where SF is endemic. The patient showed clinical manifestations and epidemiological exposure compatible with SF, and the infection was confirmed by molecular biology techniques.

Although the single threshold is still considered a suitable and easy-to-do technique to extract water features in spatiotemporal analysis, it leads to unavoidable errors. This paper uses an enumerative search to optimize thresholds over satellite-derived modified normalized difference water index (MNDWI). We employed a cross-validation approach and treated accuracy as a random variable in order to: (a) investigate uncertainty related to its application; (b) estimate non-optimistic errors involving single thresholding; (c) investigate the main factors that affect the accuracy’s model, and (d) compare satellite sensors performance. We also used a high-resolution digital elevation model to extract water elevations values, making it possible to remove topographic effects and estimate non-optimistic errors exclusively from orbital imagery. Our findings evidenced that there is a region where thresholds values can vary without causing accuracy loss. Moreover, by constraining thresholds variation between these limits, accuracy is dramatically improved and outperformed the Otsu method. Finally, the number of scenes employed to optimize a single threshold drastically affects the accuracy, being not appropriate using a single scene once it leads to overfitted threshold values. More than three scenes are recommended.

The Caatinga biome, the only exclusively Brazilian biome, plays a crucial yet understudied role in regional and global carbon dynamics. Using column-averaged dry-air mole fraction of CO 2 (XCO 2 ) data from NASA’s Orbiting Carbon Observatory-2 (OCO-2) between 2015 and 2022, this study investigates spatial and temporal anomalies across distinct phytoecological biozones of the Caatinga. Anomaly detection, spatial autocorrelation (Local Moran’s I), time-series modeling (ARIMA), and correlation analyses with vegetation and climate indices (NDVI, EVI, LAI, land surface temperature, and precipitation) were applied to evaluate the biome’s carbon balance. Results reveal heterogeneous XCO 2 patterns, with predominantly negative or neutral anomalies, confirming the Caatinga’s role as a carbon sink, though punctuated by localized positive anomalies indicating emission hotspots. The Savanna-Steppe and Pioneer Formation biozones exhibited the strongest seasonal and spatial clustering of positive anomalies, highlighting vulnerability to land-use pressures and climatic extremes. Forested biozones, particularly Open and Dense Ombrophilous Forests, showed increasing anomaly trends in recent years, suggesting a potential weakening of sink capacity. Correlations revealed distinct biome-specific responses: positive associations between XCO 2 and precipitation in transitional and pioneer formations, and negative associations with vegetation indices in savanna areas, emphasizing hydrological control of carbon fluxes. The findings demonstrate that the Caatinga exhibits both resilience and vulnerability, with its carbon balance strongly modulated by climatic variability, vegetation structure, and anthropogenic pressures. These results underscore the biome’s strategic role in climate mitigation and the urgent need for targeted conservation and restoration policies to safeguard its carbon sequestration potential.

This study presents a brief bibliometric investigation of thermogravimetric pyrolysis of carnauba biomass (Copernicia prunifera), a palm tree native to northeastern Brazil belonging to the Arecaceae family. The objective was to analyze the scientific production and methods used to evaluate the kinetic parameters of biomass pyrolysis. An analysis was conducted using the Scopus, ScienceDirect, and Web of Science databases, and VOSviewer and Bibliometrix software. The methodology allows the generation of clusters and tables of scientific production, including authors, co-authors, affiliations, institutions, journals, and keywords. The search yielded 1983 articles, and after the application of exclusion criteria, 919 articles were retained, forming the basis for the bibliometric analysis. It provided an overview of thermogravimetric pyrolysis of carnauba research and identified areas that require further study. It also identified which universities and researchers have devoted the most effort to this area of research, the key findings, and areas that require further investment to complement existing research. Additionally, the study indicated the suitability of the Friedman method for determining kinetic parameters in biomass pyrolysis.

The Brazilian semi-arid region, marked by erratic rainfall and severely degraded soils, presents critical challenges for sustainable agriculture. In this context, the reuse of treated domestic wastewater—collected from a septic tank and anaerobic filter system—offers a promising strategy to enhance plant productivity and rehabilitate soil conditions, particularly within the Caatinga biome. This study evaluated the long-term (four-year) effects of irrigation with pure water versus treated domestic wastewater on plant dry biomass, soil fertility, and rhizospheric microbial activity in a degraded Planosol. Two plant types were assessed: a C₄ species ( Mimosa caesalpiniifolia ) and a CAM species ( Opuntia atropes ). Results demonstrated that treated wastewater irrigation significantly increased dry biomass, with a 12.18% increase in the C₄ species and a 29.33% increase in the CAM species. Soil chemical fertility improved notably, with wastewater application raising soil pH by 5.0%, increasing soil organic carbon by 87.9%, and enhancing nutrient availability, including nitrogen, potassium, magnesium, and sodium. A 37.5% reduction in exchangeable aluminum further indicated mitigation of soil acidity. Microbial responses varied between species: while soil respiration increased in both rhizospheres—more prominently in CAM species—microbial biomass carbon rose significantly in the C₄ rhizosphere but declined in CAM, suggesting species-specific microbial interactions. These findings support the potential of treated domestic wastewater as a nutrient-rich, low-cost irrigation alternative for improving plant performance and soil quality in semi-arid degraded lands. Nevertheless, potential risks—including salinity build-up and pathogen persistence—necessitate long-term monitoring and further environmental safety assessments. By integrating plant physiology, soil chemistry, and microbial ecology, this study offers a comprehensive approach to evaluating wastewater reuse as a sustainable agricultural and ecological restoration practice in the Caatinga biome.

Umbu ( Spondias tuberosa Arruda) is an endemic fruit tree restricted to the Brazilian seasonally dry tropical forest called Caatinga. This study aimed to evaluate the structure and genomic diversity of umbu trees from seven locations in the Caatinga biome, distributed among four Brazilian states. Using genotyping-by-sequencing (GBS), a total of 5,336 SNPs were obtained, of which 250 showed outlier behavior. Therefore, 5,086 neutral SNPs were used for population structure and genetic diversity analyses. Both discriminant analysis of principal components (DAPC) and neighbor-joining cluster analyses classified the accessions into four groups, with a genetic structure observed among groups, disagreeing with our initial hypothesis of low genetic structure between locations. Isolation by distance (r 2  = 0.974; p = 0.0015) was detected. Moderate to high levels of genetic diversity were found, with the average observed heterozygosity ( H O  = 0.221) higher than the expected heterozygosity ( H E  = 0.199) and with negative inbreeding coefficient ( F IS ) values. Most genetic variation was found within locations, although high diversity between locations (22.1%) was observed. The results obtained are important for understanding the levels and distribution of genetic variation, suggesting that most locations are priorities for conservation actions, contributing with different alleles to the species' gene pool in Brazil.

Environmental and spatial factors are known as the main determinants of community variation in aquatic organisms. However, historical factors may interact with local processes to regulate community structure patterns. Here we compared historical, environmental, and spatial factors in a multi-scale approach in order to identify the main drivers structuring species composition and functional diversity of fish communities in forest enclaves across three hydrographic basins in semiarid Brazil Caatinga biome. We initially modeled spatial structure within each basin using asymmetric eigenvector maps (AEM). We then partitioned the explanation of the variation in local community structure into three groups of predictor variables: (1) environmental variables, (2) spatial variables, and (3) phylogenetic history. Biogeographical bias was assessed using a basin identity matrix as covariable. The combination of 1, 2, and 3 explained the variation in species composition, while pure spatial, phylogenetic, and environmental components explained the distribution of functional groups and their nested patterns. Our findings confirmed the importance of phylogenetic history, as well as the usefulness of robust methods in community studies in refining explanations of the processes determining variation in species composition and functional groups.

This study provides a comprehensive overview of Phase I of the deforestation dryland alert system. It focuses on its operation and outcomes from 2020 to 2022 in the Caatinga biome, a unique Brazilian dryland ecosystem. The primary objectives were to analyze deforestation dynamics, identify areas with highest deforestation rates, and determine regions that require prioritization for anti-deforestation efforts and conservation actions. The research methodology involved utilizing remote sensing data, including Landsat imagery, processed through the Google Earth Engine platform. The data were analyzed using spectral unmixing, adjusted Normalized Difference Fraction Index, and harmonic time series models to generate monthly deforestation alerts. The findings reveal a significant increase in deforestation alerts and deforested areas over the study period, with a 148% rise in alerts from 2020 to 2022. The Caatinga biome was identified as the second highest in detected deforestation alerts in Brazil in 2022, accounting for 18.4% of total alerts. Hexagonal assessments illustrate diverse vegetation cover and alert distribution, enabling targeted conservation efforts. The Bivariate Choropleth Map demonstrates the nuanced relationship between alert and vegetation cover, guiding prioritization for deforestation control and native vegetation restoration. The analysis also highlighted the spatial heterogeneity of deforestation, with most deforestation events occurring in small patches, averaging 10.9 ha. The study concludes that while the dryland alert system (SAD-Caatinga—Phase I) has effectively detected deforestation, ongoing challenges such as cloud cover, seasonality, and more frequent and precise monitoring persist. The implementation of DDAS plays a critical role in sustainable forestry by enabling the prompt detection of deforestation, which supports targeted interventions, helps contain the process, and provides decision makers with early insights to distinguish between legal and illegal practices. These capabilities inform decision-making processes and promote sustainable forest management in dryland ecosystems. Future improvements, including using higher-resolution imagery and artificial intelligence for validation, are essential to detect smaller deforestation alerts, reduce manual efforts, and support sustainable dryland management in the Caatinga biome.

Parasites are important components of the immense n-dimensional trophic network that connects all living beings because they, among others, forge biodiversity and deeply influence ecological evolution and host behavior. In this sense, the influence of Trypanosomatidae remains unknown. The aim of this study was to determine trypanosomatid infection and richness in rats, opossums, and dogs in the semiarid Caatinga biome. We submitted DNA samples from trypanosomatids obtained through axenic cultures of the blood of these mammals to mini exon multiplex-PCR, Sanger, and next-generation sequencing targeting the 18S rDNA gene. Phylogenetic analyses were performed to identify genetic diversity in the Trypanosomatidae family. Shannon, Simpson, equability, and beta-diversity indices were calculated per location and per mammalian host. Dogs were surveyed for trypanosomatid infection through hemocultures and serological assays. The examined mammal species of this area of the Caatinga biome exhibited an enormous trypanosomatid species/genotypes richness. Ten denoised Operational Taxonomic Units (ZOTUs), including three species ( Trypanosoma cruzi , Trypanosoma rangeli and Crithidia mellificae ) and one Trypanosoma sp. five genotypes/lineages ( T. cruzi DTU TcI, TcII, and TcIV; T. rangeli A and B) and four DTU TcI haplotypes (ZOTU1, ZOTU2, ZOTU5, and ZOTU10 merged), as well as 13 Amplicon Sequence Variants (ASVs), including five species ( T. cruzi , T. rangeli , C. mellificae , Trypanosoma dionisii , and Trypanosoma lainsoni ), five genotypes/lineages (same as the ZOTUs) and six DTU TcI haplotypes (ASV, ASV1, ASV2, ASV3, ASV5 and ASV13), were identified in single and mixed infections. We observed that trypanosomatids present a broad host spectrum given that species related to a single host are found in other mammals from different taxa. Concomitant infections between trypanosomatids and new host-parasite relationships have been reported, and this immense diversity in mammals raised questions, such as how this can influence the course of the infection in these animals and its transmissibility. Dogs demonstrated a high infection rate by T. cruzi as observed by positive serological results (92% in 2005 and 76% in 2007). The absence of positive parasitological tests confirmed their poor infectivity potential but their importance as sentinel hosts of T. cruzi transmission.