Search Results (320)

The Amazon Basin harbors a high diversity of phlebotomine sand flies, including several species that act as vectors of zoonotic pathogens such as Leishmania. Land-use changes, particularly forest conversion to agriculture, alter the sand fly diversity and community structure, with implications for the transmission of American Tegumentary Leishmaniasis (ATL). We evaluated the effects of forest-to-agriculture conversion on sand fly diversity and species composition in two rural areas, on opposite sides of the Amazonas River, in the Brazilian Amazon Region. Sand flies were collected using Center of Disease Control (CDC) light traps, installed in the forest and cropland environments, at the Presidente Figueiredo (North) and Urucurituba (South) municipalities, in Amazonas, Brazil. We collected a total of 1778 phlebotomine sand flies from 15 genera and 69 species. The most abundant species were Micropygomya rorotaensis (n = 436; 24.52%), Nyssomyia antunesi (n = 297; 16.70%), Sciopemyia sordellii (n = 101; 5.68%), Bichromomyia flaviscutellata (n = 84; 4.72%) and Evandromyia monstruosa (n = 72; 4.04%). In addition, four sand fly species were recorded for the first time in the Amazonas state: Brumptomyia mesai, Pressatia calcarata, Evandromyia aldafalcaoae and Lutzomyia carvalhoi. Sand fly richness, diversity, and community composition varied between riversides and environments, reflecting strong effects of anthropogenic disturbance. Although croplands supported reduced and more heterogeneous assemblages, several medically important vector species persisted across both environments. Species turnover was high, but patterns of species loss were weak, suggesting that community reorganization was driven by non-directional compositional change process. Our results indicate that land-use change reshapes sand fly communities without eliminating disease vectors, potentially increasing ATL transmission risk at the forest–anthropic interface. Full article

Sexually transmitted infections (STIs) caused by C. trachomatis and HPV are the most prevalent worldwide. College students are characterized by being young women of reproductive age who may have risky sexual behavior. To describe the prevalence and factors associated with endocervical infection by C. trachomatis and HPV in college women in the Brazilian Amazon. Endocervical secretions were collected. The ompA gene of C. trachomatis and the L1 gene of HPV were detected. The Chi-square test, Fisher’s exact test, G test, Odds Ratio, and Multiple Logistic Regression were used with 95% confidence interval and p ≤ 0.05. The overall prevalence of endocervical infection by C. trachomatis was 8.3% (25/302) and by HPV was 28.9% (87/302). Low income was associated with sexually transmitted infection by C. trachomatis (14.8%, p = 0.0336). Those under 25 years old had twice the chance of HPV infection [39.3%, (OR: 2.6989), 95% CI: 1.6054–4.5371, p = 0.0002], as did women without children [31.8%, (OR: 2.333), CI: 1.1235–4.8461, p = 0.0307]. Women who did not study in a public school had 63% reduced risk of acquiring HPV infection [45.8% (OR: 0.3713), CI: 0.1951–0.7064, p = 0.0035]. C. trachomatis and HPV infections were present in low-income, childless young women who attended public schools, requiring the intensification of STI prevention policies in the Amazon region. Full article

Background/Objectives: Antimicrobial resistance (AMR) is a global health threat, with raw milk serving as a potential reservoir for antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs). This study characterized the resistome and mobilome of raw milk from cows (Bos taurus) and water buffalo (Bubalus bubalis) in the Brazilian Amazon, a region where unpasteurized dairy consumption is culturally ingrained. Methods: Using shotgun metagenomic sequencing, we analyzed 32 pooled milk samples from extensive and semi-intensive farms in the Manaus Metropolitan Region. Results: Sequencing yielded over 3.1 million contigs. While cow milk showed a higher prevalence of positive samples (80%), buffalo milk exhibited a significantly higher abundance and diversity of ARG-associated contigs (301 contigs vs. 85 in cows). Clinically relevant genes were identified, including AbaQ, ArnT, and KpnF, alongside complex multi-AMR cassettes co-occurring with plasmids and widespread viral sequences (dominated by Caudoviricetes). Integrons were ubiquitous in cattle and highly prevalent in buffalo samples. Conclusions: These findings indicate that raw milk in the Amazon harbors a rich reservoir of resistance determinants and MGEs, likely driven by farm-level antibiotic usage. This underscores a critical food safety risk and highlights the need for One Health-based surveillance in the region. Full article

A significant number of regional boats are used in the Brazilian Amazon to perform a range of social activities. However, the estimation of their propulsion parameters still requires exploring technically supported methods if the efficiency and sustainability of inland navigation is to be optimized. This study explores various approaches for estimating the total resistance and effective propulsive power required by regional boats. The research examines the real case of a rabeta, a regional boat commonly used in the Brazilian Amazon, by analyzing the applicability at full scale of two approaches: the conventional Mercier–Savitsky pre-planing method and a multiphase computational fluid dynamics (CFD) approach. Using experimental data, such as boat speed and the patterns of boat-generated waves, computational analysis and the comparison of results, respectively, were carried out. It was found that for the case considered, the CFD results underpredicted the conventional approach in less than 10% for the minimum and maximum drafts considered, suggesting that both approaches are useful for estimating the effective power of artisanal boats. However, the use of CFD has the potential to visualize a greater number of parameters, such as the generated waves during vessel motion, which can facilitate the optimization of the hydrodynamics of boats, thus contributing to the sustainability of inland navigation in the region. The procedure employed in this study can be further extended to estimate the propulsive parameters of other regional vessels in the Amazon and similar areas. Full article

Deforestation in unprotected areas (UPAs) within the Brazilian Amazon affects environmental sustainability and regional climate. This study quantifies shifts in near-surface air temperature, precipitation, and evapotranspiration (ET) during the dry season resulting from UPA loss. Utilizing a five-year ensemble (2015–2019) to isolate the climatic response from interannual variability, simulations indicate a warmer (+1.0 ± 0.4 °C) and drier climate, characterized by a basin-wide 12 ± 8% reduction in precipitation and a 12 ± 4% reduction in ET following UPA removal. This shifted climate state extends to Rondônia, a southwestern state where detailed risk mapping was developed by integrating changes in climate variables with socio-economic, agricultural, and demographic. UPA deforestation, largely external to Rondônia, is associated with a simulated decrease in precipitation by 20 ± 7% and ET by 11 ± 9% coupled with an increase in air temperature by 1.2 ± 0.4 °C. These shifts indicate increased vulnerability for municipalities, including the capital, potentially affecting agricultural productivity. Findings suggest that to protect remaining forests these biophysical risks must be mitigated. This study establishes a spatial framework for identifying municipalities most suceptible to the climatic shifts triggered by UPA loss. Full article

Forest fires release various chemical compounds that directly degrade air quality and endanger human health. This study examines the occurrence of forest fires in six Brazilian biomes over a 22-year period (1999–2021). The primary purpose is to identify significant meteorological predictors for the monthly number of hot spots using a standardized statistical framework. Fire hotspots were identified using satellite thermal sensors (AVHRR and MODIS), and we employed a standardized negative binomial regression modeling approach to analyze the relationship between meteorological variables and fire hotspots in all six Brazilian biomes simultaneously, providing a comprehensive comparative perspective often lacking in studies focused on isolated regions. The results show that the Amazon and Cerrado biomes have the highest absolute number of fires, which is consistent with their size and vegetation structure. To avoid bias associated with biome size, fire occurrence was additionally estimated using hotspot density normalized by biome area (hotspots per km²). Using these models, significant factors for fire occurrence were identified, namely the main meteorological variables—temperature, precipitation and wind speed. By comparing the performance of the models in different biomes, we aimed to better understand regional fire dynamics. The model’s ability to predict the expected number of fires based on these variables provides a key tool for preventive air quality monitoring. Such a predictive model serves as a basis for developing early warning systems, assessing potential health risks for the population, and adopting targeted fire management policies. Full article

Platonia insignis Mart. (Clusiaceae) is a native fruit tree of great ecological and socioeconomic importance in the Brazilian Amazon and Cerrado. However, habitat loss is threatening its genetic variability. We investigated whether habitat fragmentation across the Amazon, Cerrado, and transition zones shapes the genetic diversity and population structure of five natural populations of P. insignis, using ISSR markers. Leaf samples from 13–15 individuals per population were collected, and DNA was extracted using the CTAB protocol. Twelve ISSR primers amplified 149 loci, used to estimate genetic parameters. AMOVA showed that 73.58% of genetic variation occurred within populations and 26.41% among populations (F_ST = 0.261). Amazonian populations exhibited the highest genetic diversity, while transition zone populations had the lowest values. The Cerrado population was genetically distinct and maintained moderate intrapopulation diversity. Bayesian clustering, PCoA, and UPGMA revealed three genetic groups corresponding to the sampled regions. Transitional populations showed high genetic admixture, indicating their role as potential corridors for gene flow. Our results highlight the need to preserve genetically diverse Amazonian populations, safeguard the Cerrado population as an evolutionarily significant unit, and maintain transitional populations to promote landscape connectivity. The study provides a genetic baseline to support conservation and management of P. insignis germplasm resources. Full article

The Brazilian Amazon has been endangered by agro-extractivism, a development model characterized by the expansion of the agricultural frontier to produce raw commodities embedded in power-asymmetrical commodity chains. Recently, the socio-biodiversity economy has emerged as an alternative development model, aimed at reconciling local development with nature conservation. While the environmental and social contrasts between the two models are well documented, the commercial dimension of the socio-biodiversity economy remains underexplored. These two models are typically approached as separate systems, yet their coexistence and interaction within the same actors and across interconnected value chains has not been empirically examined. In this paper, we provide a qualitative analysis of dynamics and upgrading mechanisms in two cocoa value chains in the Brazilian Amazon: raw (bulk) and fine-flavor (fino) cocoa. Through this comparison, we examine how each chain differs in terms of commercial relations and how socio-biodiversity economy and agro-extractivism interact within the commercial sphere. The research took place in three municipalities along the Transamazon highway between March and September 2024. Data were gathered through semi-structured interviews with cocoa producers, buyers, and supporting actors such as NGOs, companies, and public agencies, complemented by participant observation and participation in cocoa-related events. Findings suggest that the bulk and fino cocoa chains present distinct commercial configurations, the former displaying agro-extractivist patterns, the latter consistent with the socio-biodiversity economy. Cocoa production in the region is part of an emergent socio-biodiversity economy that remains commercially embedded in agro-extractivism. Notably, farmers engage in both chains as part of their livelihood strategies, while relying predominantly on the bulk trade. We argue that the fino cocoa chain may represent a pathway for transforming commercial relations in the region, provided that the structural conditions sustaining agro-extractivist patterns in the bulk chain are addressed. More broadly, we show that production-level transitions toward sustainable farming do not automatically translate into the transformation of commercial relations, and call for greater analytical attention to the commercial dimension of socio-biodiversity economies. Full article

At least seven species of wild cats inhabit Colombia, and these species are also distributed throughout Mexico, Central America, and the rest of South America (jaguar, puma, jaguarundi, ocelot, margay, tigrina, and Pampas cat). A checklist and review of phylogeographic and population genetic studies on these seven wild cat species has been conducted here, as this information is vital for effective conservation programs. The jaguar is the feline species on which the most population genetic studies have been carried out in the Neotropics. In general, little genetic structure has been found at a macro-geographic scale. Genetic diversity is high in countries such as Colombia, Peru, and Bolivia, and generally throughout the Amazon basin. However, genetic diversity is more moderate or even significantly lower in Mexico and the Brazilian Atlantic Forest. Much of the genetic research on the jaguar has focused on Brazil, Mexico, and Belize, but Colombia is also very well represented in these studies. However, there is a complete or very pronounced lack of data in other areas such as Venezuela, the Guianas, some Central American countries, Paraguay, and northern Argentina. After the jaguar, the most studied feline in Neotropics from a population genetics perspective is the puma. In North America, this species has low genetic diversity, while the diversity in Central America is moderate, and South America is where genetic diversity is highest. The countries best represented in these studies are Brazil (southern of the country), Mexico, Belize, and Argentina. However, countries like Colombia, Ecuador, Peru, and Paraguay are very poorly represented in puma genetic studies. Very few genetic studies have been conducted on the jaguarundi, despite its vast geographic distribution. In northern Mexico, its genetic diversity is very low, but in countries like Colombia, Peru, and Bolivia, genetic diversity is very high. Colombia is probably the country where jaguarundis have been genetically studied most extensively. The third wild cat species with the most molecular studies in Neotropics is the ocelot, although it lags considerably behind jaguars and pumas. Its genetic diversity is low in Texas and northern Mexico, but very high, especially in countries surrounding the Amazon basin. A good number of macro-geographic studies have been conducted on the ocelot, and these studies are very representative of ocelots in countries such as Colombia (probably the best represented country), Ecuador, Peru, Bolivia, Panama, and Costa Rica. However, there are other countries where molecular studies of the ocelot have not been carried out, such as Paraguay and Argentina, with the lack of such studies in Brazil being particularly noteworthy. Very few molecular studies have been conducted on the margay. In general, its genetic diversity is very high in all the studies performed. Colombia, Peru and Bolivia are very well represented, but the lack of molecular studies in Mexico, much of Central America, and South American countries such as Brazil, Paraguay, and Argentina is striking. The tigrina is one of the Neotropical wild cat species that requires the most molecular studies to unravel its complex systematics. Only the southern Brazilian tigrina (Leopardus guttulus), which was elevated to a new species, has generated comprehensive molecular information. Molecular studies of the Andean tigrina have revealed a very complex picture that, at present, does not allow us to know exactly how many species or taxa inhabit that area of South America and, therefore, to develop a conservation program that adequately correlates with that number of taxa. Finally, in the case of the Pampas cat, molecular studies are well represented with specimens from Peru, Bolivia, Chile, Argentina, Brazil and Uruguay. Studies are needed in Paraguay, and especially in Ecuador and southern Colombia (assuming a stable population of Pampas cats exists in the latter country), where even at the molecular level, the specific taxon (one species or five species) present has not yet been determined. All this information is essential for developing effective regional and global conservation programs for these magnificent creatures. In Colombia, the development of molecular studies with the puma, the tigrina, and the Pampas cat is of special interest. Full article

Carapa guianensis Aubl., widely distributed throughout the Amazon, is recognized for its ecological, economic, and social importance, and constitutes a key source of income for numerous extractive communities. However, fruit production exhibits marked spatial variation that may be influenced by soil properties and climatic factors. In this study, we assessed this variability using data from 21 studies conducted in the Brazilian Amazon, incorporating georeferenced information from each site on climate and soil characteristics. Environmental variables were evaluated using Random Forest models. Although the number of independent production estimates available in the literature is limited, average fruit productivity showed a broad range (0.34 to 34.6 kg·tree⁻¹·year⁻¹), with higher values in várzea forests (16.5 kg·tree⁻¹·year⁻¹) and lower values in igapó forests (2.5 kg·tree⁻¹·year⁻¹). The Random Forest model explained 42% of the variability in fruit production according to cross-validation, whereas the model fit using the full dataset showed a higher R² value (0.83). Soil organic carbon, mean annual temperature, and clay content were the most influential predictors. These findings demonstrate that fruit production is shaped by the interaction between edaphic and climatic conditions, which determine the species’ productivity patterns and highlight the need to foster adaptive management strategies that ensure the sustainable use of andiroba across Amazonian ecosystems. Nevertheless, it is acknowledged that the number of available production estimates is limited and that methodological heterogeneity exists among the analyzed studies. Despite this, the results reveal consistent patterns of association between Carapa guianensis fruit production and edaphoclimatic gradients, highlighting the influence of climatic and soil-related variables at a regional scale. Full article

This study presents the complete sequencing and comparative genomic analysis of Leimania (Viannia) naiffi and Leishmania (Viannia) shawi, species of epidemiological relevance in the Brazilian Amazon. Genome assemblies yielded sizes of 32.13 Mb and 32.51 Mb, with 8170 and 7767 annotated genes, respectively. Predicted gene functions were primarily related to catalytic, binding, and ATP-dependent activities. Pangenome analysis revealed a core genome of 6256 genes alongside notable species-specific differences, including 46 and 25 unique genes in L. naiffi and L. shawi. Functional screening identified pharmacologically promising proteins such as calpains, ABC transporters, and notably, GSK-3. Ploidy analysis indicated tetraploidy on chromosome 8 in L. naiffi and chromosome 2 in L. shawi. Genetic variability assessment detected 34,480 SNPs in L. naiffi and 26,562 in L. shawi, indicating greater genomic diversity in the former. Phylogenetic inference based on the polA1 gene confirmed the placement of both species within the Leishmania (Viannia) subgenus. These findings advance Leishmania genomics knowledge by highlighting unique genetic signatures, regions of high variability, and potential therapeutic targets. This work establishes a foundation for future research on evolution, pathogenicity, and drug development for leishmaniasis. Full article

The conversion of native forests into agricultural areas without conservation practices can expose tons of soil organic carbon (SOC) to the atmosphere. This study aimed to evaluate the effect of land use and cover (LULC) on C in regions of the Caiabi (SBC) and Renato (SBR) River sub-basins, located in the Brazilian Cerrado–Amazon transition. Data on physical attributes and SOC were obtained by region (upper, middle, and lower), LULC (cropland, pasture, and native forest), and depth (0–10, 10–20, and 20–40 cm), with five replicates for each variable. The highest SOC values were found in areas with higher clay contents or in areas of native forest or crop residues. In the SBC, there was a negative correlation of SOC with sand and particle density (PD) and a positive correlation with silt. In the SBR, there was a positive correlation between SOC and microporosity and total porosity, and a negative correlation with sand, soil bulk density, and PD. The highest SOC values were found in the SBC upper region, in native forest (107 Mg ha⁻¹), cropland (69 Mg ha⁻¹), and pasture (49 Mg ha⁻¹). In the SBR upper region, the values were highest in pasture and cropland (93 and 58 Mg ha⁻¹), and in the lower region, the values were highest in native forest (48 Mg ha⁻¹). SOC varied in relation to the SBC and SBR regions, the LULC, depth, and physical attributes, especially soil texture. Full article

Toxoplasmosis is a parasitic disease associated with significant morbidity and mortality. This cross-sectional study aimed to determine the prevalence, associated risk factors, and ocular health outcomes related to Toxoplasma gondii seropositivity in 161 residents from four Quilombolas communities in the northern region of Tocantins, Brazilian Legal Amazon. Peripheral blood samples were collected and tested by Enzyme-Linked Immunosorbent Assay (ELISA) for Immunoglobulin G (IgG) and/or Immunoglobulin M (IgM) and Polymerase Chain Reaction (PCR), while a standardized form was used to collect sociodemographic, health, and behavioral data. Statistical analysis, conducted using Epi-Info 3.3.2, considered T. gondii seropositivity as the primary outcome, with a significance level less than 5% (p ≤ 0.05). An overall seroprevalence of 62.11% (100/161) was observed. Key risk factors significantly, as measured by the Odds Ratio (OR), associated with T. gondii seropositivity included being elderly (OR: 4.07, CI: 2.05–8.06, p < 0.01), having cats (OR: 5.56, CI: 2.74–22.27, p < 0.01), a low parental education level (OR: 2.97, CI: 1.46–6.02, p < 0.01), children playing on the ground (OR: 2.50, CI: 1.30–4.82, p < 0.01), and having a home vegetable garden (OR: 3.80, CI: 1.94–7.47, p < 0.01). Regarding ocular health, no conclusive direct association was established between T. gondii seropositivity and specific ocular manifestations when analyzed for children and the elderly separately. Observed ocular problems in the grouped population were primarily linked to age-related comorbidities rather than parasitic infection. High rates of T. gondii seropositivity, driven by specific environmental and socioeconomic factors, highlight the vulnerability of these communities, emphasizing the need for targeted preventive strategies. Full article

Objective: To determine the prevalence of and risk factors for congenital toxoplasmosis in neonates treated in the public health network of the eastern region of the Brazilian Amazon, northern Tocantins state. Methods: A retrospective cohort study was conducted with neonates born to mothers with gestational toxoplasmosis who received care between 2017 and 2024. The outcome under analysis was positivity for immunoglobulin M in the electrochemiluminescence assay (CLIA). We estimated the prevalence of transplacental infection and respective 95% confidence intervals (95% CI) and its association with risk factors using the odds ratio (or) with a p-value < 0.05 in infected neonates before and after 16 gestational weeks at maternal infection diagnosis. Results: A total of 1142 neonates were surveyed, in which 496 were diagnosed with congenital toxoplasmosis (IgM positive), thus obtaining a prevalence of vertical transmission of 45.4%. The main risk factors for vertical transmission were the mother’s education level equal to or less than eight years, (OR = 1.5; 95% CI 1.2; 2.0) and having less than six prenatal consultations (OR = 22.8; 95% CI 3.0; 172.6). Conclusions: A high prevalence of congenital toxoplasmosis was observed, with higher rates of infection in neonates born to mothers with lower levels of education. Full article

Agro-industrial facilities host processes and products that are highly sensitive to thermal fluctuations. Given the projected increase in air temperatures in tropical regions due to climate change, improving indoor thermal conditions in these facilities has become critically important. Conventional cooling systems are widely used to maintain adequate indoor temperatures; however, they are associated with high energy consumption. In this context, Ground Source Heat Pump (GSHP) technology emerges as a promising alternative to reduce cooling loads by exchanging heat with the ground. This study evaluates the reductions in cooling energy consumption and the return on investment of a GSHP system integrated with conventional cooling system, considering a prototype agro-industrial room located in two ecotones of the Brazilian Midwest: the Amazon Forest (AF) and Brazilian Savanna (BS). Building energy simulations were performed using EnergyPlus software v. 9 under current climate conditions and climate change scenarios for 2050 and 2080. Initially, the prototype room was conditioned using a conventional HVAC system; subsequently, a GSHP system was integrated to enhance energy efficiency and reduce energy demand. Under current conditions, cooling energy demand in the BS and AF ecotones is projected to increase by 16.5% and 18.3% by 2050, and by 24.5% and 23.5% by 2080, respectively. The payback analysis indicates that the average return on investment improves under future climate scenarios, decreasing from 14.5 years under current conditions to 10.13 years in 2050 and 9.86 years in 2080. The findings contribute to understanding the thermal resilience and economic feasibility of ground-coupled heat exchangers as a sustainable strategy for mitigating climate change impacts in the agro-industrial sector. Full article