Search Results (1,226)

Since 2014, the Paleoanthropology Group of the National Museum of Natural Sciences (CSIC), in collaboration with Equatoguinean researchers, has been conducting archeo-paleontological fieldwork in Equatorial Guinea, continuing a longstanding Spanish naturalist tradition in this region of West Central Africa. These multidisciplinary investigations, framed within an archeo-paleo-anthropological approach, aim primarily to identify early human occupation in the Central African rainforests. To date, robust evidence of Pleistocene human presence has been documented, particularly through lithic assemblages. Although the scarcity and fragmentation of well-dated sites in Central Africa complicate chronological placement, technological traits observed in the lithic industries recorded in Equatorial Guinea show clear affinities with the African Middle Stone Age (MSA). Complementary taphonomic analyses of faunal remains have been undertaken to better understand bone preservation and fossilization processes under tropical rainforest conditions, thereby contributing to the interpretation of archeological contexts. In parallel, ongoing primatological research within the project—focused on extant primates in their natural habitats—seeks to provide ethological models relevant to the study of hominin locomotor evolution. Notably, the project has led to the ecogeographic characterization of the Engong chimpanzee group in Monte Alén National Park, one of the country’s most pristine protected areas. Full article

Wet areas, which are locations in the landscape that consistently retain moisture, and channel networks are important landscape compartments, with key hydrological and ecological functions. Hence, defining their spatial boundaries is an important step towards sustainable watershed management. In catchments of developing countries, wet areas and small order channels of river networks are rarely mapped, although they represent a crucial component of local livelihoods and ecosystems. In this study, topographic attributes generated with a 30 m SRTM DEM were used to map wet areas and stream networks of two tropical catchments in Central Brazil. The topographic attributes for wet areas were the local slope and the slope curvature, and the Topographic Wetness Index (TWI) was used to delineate the stream networks. Threshold values of the selected topographic attributes were calibrated in the Santa Maria catchment, comparing the synthetically generated wet areas and drainage networks with corresponding reference (map) features, and validated in the nearby Santa Maria basin. Drainage network and wet area delineation accuracies were estimated using random basin transects and multi-criteria and confusion matrix methods. The drainage network accuracies were 67.2% and 70.7%, and wet area accuracies were 72.7% and 73.8%, for the Santa Maria and Gama catchments, respectively, being equivalent or higher than previous studies. The mapping errors resulted from model incompleteness, DEM vertical inaccuracy, and cartographic misrepresentation of the reference topographic maps. The study’s novelty is the use of readily available information to map, with simplicity and robustness, wet areas and channel initiation in data-scarce, tropical environments. Full article

Cancer disparities in low- and middle-income countries (LMICs) arise from multifaceted interactions between environmental exposures, infectious agents, and systemic inequities, such as limited access to care. The exposome, a framework encompassing the totality of non-genetic exposures throughout life, offers a powerful lens for understanding these disparities. In LMICs, populations are disproportionately affected by air and water pollution, occupational hazards, and oncogenic infections, including human papillomavirus (HPV), hepatitis B virus (HBV), Helicobacter pylori (H. pylori), human immunodeficiency virus (HIV), and neglected tropical diseases, such as schistosomiasis. These infectious agents contribute to increased cancer susceptibility and poor outcomes, particularly in immunocompromised individuals. Moreover, climate change, food insecurity, and barriers to healthcare access exacerbate these risks. This review adopts a population-level exposome approach to explore how environmental and infectious exposures intersect with genetic, epigenetic, and immune mechanisms to influence cancer incidence and progression in LMICs. We highlight the critical pathways linking chronic exposure and inflammation to tumor development and evaluate strategies such as HPV and HBV vaccination, antiretroviral therapy, and environmental regulation. Special attention is given to tools such as exposome-wide association studies (ExWASs), which offer promise for exposure surveillance, early detection, and public health policy. By integrating exposomic insights into national health systems, especially in regions such as sub-Saharan Africa (SSA) and South Asia, LMICs can advance equitable cancer prevention and control strategies. A holistic, exposome-informed strategy is essential for reducing global cancer disparities and improving outcomes in vulnerable populations. Full article

Introduction: Leptospirosis is an under-recognized zoonosis that affects both tropical and temperate regions. While it is often associated with exposure to contaminated water or infected animals, its presentation and epidemiology in Mediterranean countries remain incompletely understood. This retrospective cohort study investigates the clinical and epidemiological profile of leptospirosis in Crete, Greece, a region where data are scarce. Methods: All adult patients with laboratory-confirmed leptospirosis admitted to three major public hospitals in Crete, Greece, between January 2019 and December 2023 were included in the analysis. Diagnosis was made through serologic testing along with compatible clinical symptoms. Results: A total of 17 patients were included. Their median age was 48 years, with a predominance of males (70.6%). Notably, more than half of the patients had no documented exposure to classic risk factors such as rodents or standing water. Clinical presentations were varied but commonly included fever, fatigue, acute kidney injury, and jaundice. Of the patients who underwent imaging, most showed hepatomegaly. The median delay from symptom onset to diagnosis was 11 days, underscoring the diagnostic challenge in non-endemic areas. Ceftriaxone was the most frequently administered antibiotic (76.5%), often in combination with tetracyclines or quinolones. Despite treatment, three patients (17.6%) died, all presenting with severe manifestations such as ARDS, liver failure, or shock. A concerning increase in cases was noted in 2023. Conclusions: Leptospirosis can present with severe and potentially fatal outcomes even in previously healthy individuals and in regions not traditionally considered endemic. The relatively high mortality and disease frequency noted emphasize the importance of maintaining a high index of suspicion. Timely diagnosis and appropriate antimicrobial therapy are essential to improving patient outcomes. Additionally, the need for enhanced public health awareness, diagnostic capacity, and possibly environmental surveillance to control this neglected but impactful disease better, should be emphasized. Full article

Nitrifying bacteria, including ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), are players in the nitrogen cycle but pose serious health risks when colonizing drinking water distribution networks (DWDNs). While the global impact of these bacteria is increasingly recognized, a significant research gap remains concerning their effects in tropical regions, particularly in developing countries. This study aims to bridge that gap by systematically reviewing the existing literature on nitrifying bacteria in DWDNs, their behavior in biofilms, and associated public health risks, particularly in systems reliant on surface water sources in tropical climates. Using the PRISMA guidelines for systematic reviews, 51 relevant studies were selected based on content validity and relevance to the research objective. The findings highlight the critical role of nitrifying bacteria in the formation of nitrogenous disinfection by-products (N-DBPs) and highlight specific challenges faced by developing countries, including insufficient monitoring and low public awareness regarding safe water storage practices. Additionally, this review identifies key surrogate indicators, such as ammonia, nitrite, and nitrate concentrations, that influence the formation of DBPs. Although health risks from nitrifying bacteria are reported in comparable studies, there is a lack of epidemiological data from tropical regions. This underscores the urgent need for localized research, systematic monitoring, and targeted interventions to mitigate the risks associated with nitrifying bacteria in DWDNs. Addressing these challenges is essential for enhancing water safety and supporting sustainable water management in tropical developing countries. Full article

Malaria is a parasitic infectious disease that is endemic in many tropical countries. Even though several effective antimalarial agents have been implemented, treatment failure still occurs, and malaria continues to cause neurological complications and death, particularly in severe or drug-resistant cases. Hence, novel therapeutic agents with distinct mechanisms of action, as well as alternative chemical compounds that can overcome resistance, are still needed to improve malaria therapy. This study aimed to investigate the antimalarial activities of Brucea javanica, a tropical plant extracts against Plasmodium falciparum, the major species associated with severe malaria. In this study, malaria parasites were treated with plant extracts using single and co-incubation methods, along with artesunate and chloroquine, and their inhibitory effect on parasite development was determined by microscopy. The results show that all tested doses of the extracts that effectively inhibited malaria parasites did not cause hemolysis of red blood cells (RBCs). The root extract (RE) and fruit extract (FE) inhibited parasite growth at IC₅₀ values of 0.41 ± 1.14 µg/mL and 0.26 ± 1.15 µg/mL, respectively. These plant extracts significantly interrupted malaria development at the ring stage, as presented by a reduction in the conversion rate to trophozoites and schizonts. The defective parasites treated with plant extracts were characterized by nuclear clumping, leading to pyknotic cell death. Moreover, RE and FW extracts elicited an additive effect with artesunate and chloroquine, significantly reducing IC₉₀ levels for the inhibition of parasite development. In conclusion, B. javanica extracts inhibited the asexual blood-stage development of malaria parasites. They distinctively show the additive effects of ATS and CRQ, elucidating their potential for further studies on novel formulas of antimalarial drug regimens. Full article

The case-fatality rate of severe leptospirosis can exceed 50%. This retrospective cohort study examined 111 individuals with laboratory-confirmed leptospirosis admitted to Cairns Hospital, a referral hospital in tropical Australia, between January 2015 and June 2024. We examined the patients’ demographic, clinical, laboratory and imaging findings at presentation and then correlated them with the patients’ subsequent clinical course. Severe disease was defined as the presence of pulmonary haemorrhage or a requirement for intensive care unit (ICU) admission. The patients’ median (interquartile range) age was 38 (24–55) years; 85/111 (77%) were transferred from another health facility. Only 13/111 (12%) had any comorbidities. There were 63/111 (57%) with severe disease, including 56/111 (50%) requiring ICU admission. Overall, 56/111 (50%) required vasopressor support, 18/111 (16%) needed renal replacement therapy, 14/111 (13%) required mechanical ventilation and 2/111 (2%) needed extracorporeal membrane oxygenation. Older age—but not comorbidity—was associated with the presence of severe disease. Hypotension, respiratory involvement, renal involvement and myocardial injury—but not liver involvement—frequently heralded a requirement for ICU care. Every patient in the cohort survived to hospital discharge. Leptospirosis can cause multi-organ failure in otherwise well young people in tropical Australia; however, patient outcomes are usually excellent in the country’s well-resourced health system. Full article

Dengue virus serotypes 1-4 (DENV1-4) have spread through tropical and subtropical countries, causing endemic and epidemic diseases. Recently, a novel field approach using the Wolbachia symbiont was proposed to suppress DENV transmission via the mosquito vectors Aedes aegypti and Aedes albopictus. Previously, we showed that a Wolbachia strain, wMelPop, suppresses DENV2 replication in the C6/36 albopictus cell line, with the mutant DENV2 appearing and replacing the wild type DENV2. In this study, we expanded the analysis to include replications of all DENV serotypes 1-4, effects of wAu Wolbachia in C6/36 cells, and wMelPop-influences on the Aag2 aegypti cell line. It was revealed that both wAu and wMelPop reduce all DENV infectious titers without dominant appearances of the mutant viruses, despite varied effects on the viral copy numbers. The host transcriptomic profiles by RNA-seq were also variously altered by wAu and wMelPop (ranging from 10 to 30%, Log₂FC > 2 or <−2, p < 0.05). Those transcripts were not further altered by DENV infection. In contrast, abundant transcriptomic alterations by DENV infection in naïve C6/36 and Aag2 cells were blocked by either wAu or wMelPop. These results indicate that Wolbachia prevents host cellular transcriptomic alterations which are induced by DENV infection, affecting the cellular homeostasis necessary for DENV replication. Full article

Tropical fruits have become increasingly popular due to their interesting nutritional composition. This rise in their consumption has resulted in more by-products generated during their production, processing, and commercialization. Papaya, for instance, is one of the leading tropical fruits produced globally due to its essential macro- and micronutrients for a healthy diet. On the other hand, dragon fruit, less known worldwide, is gaining popularity due to its nutrient and bioactive compound content. This review uses bibliometric analysis as a tool to investigate the scientific literature related to these two fruits, focusing specifically on their by-products. The objective is to identify the key authors and countries that are making substantial contributions to the research on these fruits and their by-products, such as peels and seeds. It will provide an overview of existing topics and highlight areas needing further investigation to enhance understanding and practical applications. This approach will help guide future research and innovations related to these fruits and their potential uses. Full article

After decades of calls for more sustainable land use systems, there is still a lack of consensus on an appropriate way forward, especially for tropical and subtropical agroecosystems. Land Maxing utilises appropriate, community-based interventions to fortify and maximise the multiple, long-term benefits and interest flows from investments that rebuild all six essential capitals of sustainable development (natural, social, human, physical, financial and political/corporate will) for resource-poor smallholder communities in tropical and subtropical countries. Land Maxing adds domestication of overlooked indigenous food tree species, and the commercialization of their marketable products, to existing land restoration efforts while empowering local communities, enhancing food sovereignty, and boosting the local economy and overall production. These agroecological and socio-economic interventions sustainably restore and intensify subsistence agriculture replacing conventional negative trade-offs with fortifying ‘trade-ons’. Land Maxing is therefore productive, regenerative, remunerative and transformative for farming communities in the tropics and sub-tropics. Through the development of resilience at all levels, Land Maxing uniquely addresses the big global issues of environmental degradation, hunger, malnutrition, poverty and social injustice, while mitigating climate change and restoring wildlife habitats. This buffers subsistence farming from population growth and poor international governance. The Tropical Agricultural Association International is currently planning a programme to up-scale and out-scale Land Maxing in Africa. Full article

Noni fruit is a tropical fruit that is widespread in the Pacific Island region and in the province of Hainan in China. Noni fruit is rich in various active compounds and has long been consumed in Pacific Island countries as a traditional food and medicinal plant with anti-inflammatory and immunomodulatory properties. While recent studies have reported on the constituents and effects of noni fruit, there are few comprehensive summaries on the functionality and development of its applications. Therefore, based on the varieties, origin, ripening stage, and extraction methods of noni fruit, this manuscript summarizes the constituents and content changes of noni fruit, explains its important health benefits and mechanisms of action, analyzes the process of fermented food production and the fermentation strains of noni fruit on the quality of the product and its taste, and aims to support the scientific development and utilization of noni fruit as well as the healthy growth of its industry. Full article

Food security remains one of the most critical global challenges of the 21st century. Traditional tree crops domesticated by indigenous people have the potential to increase food security and improve the livelihoods of smallholders in developing countries. However, the nut characteristics of many traditional tree crop species in the tropics are poorly understood. In particular, physical and chemical characteristics are important to explore when selecting trees to commercialise. Three species, Barringtonia procera, B. edulis, and B. nova-hiberniae, have a long history of traditional use and domestication in Pacific Island countries. The aim of this study was to explore the physical and chemical characteristics of Barringtonia spp. in three Pacific countries: Solomon Islands, Vanuatu, and Fiji. There were significant differences in kernel weight, oil concentration, and fatty acid concentration among the countries. The kernel weight was significantly higher in Solomon Islands compared with those in Vanuatu and Fiji (9.65 g, 7.61 g, and 5.64 g, respectively). Average kernel weight in Fiji was well above 3 g, which indicated that processing could be commercially viable. The total oil concentration was significantly higher in Vanuatu and Solomon Islands than Fiji, with average concentrations of 38.96% in Solomon Islands, 47.11% in Vanuatu, and 26.20% in Fiji. Barringtonia spp. exhibited high concentrations of unsaturated fatty acids, similar to other tropical nuts, which suggests that it may be a potential healthy oil for human consumption. Notably, kernel size, oil concentration, and fatty acid composition varied geographically, potentially due to climatic differences and historical seed transfer. Our study demonstrated the potential of Barringtonia to be commercialised to enhance food and nutrition security and provide a guide for cultivar selection. Full article

Tetrodotoxin (TTX), earlier known as a tropical paralytic neurotoxin from pufferfish poisoning, has increasingly been occurring in edible marine species, including filter-feeding bivalves, from relatively cold marine waters of some European countries. The defined conditions that promote the production of TTX, its origin or the processes of its accumulation in seafood are still not clarified. Recent studies in temperate waters show, however, that the accumulation of quantifiable levels of TTX in bivalves appears to be influenced by seawater temperature (>15 °C), which indicates a seasonal occurrence at these latitudes. Uncertainties still remain regarding how seawater temperature interacts with other climate and environmental factors or organisms in the marine ecosystem to result in detectable levels of TTX in shellfish. Knowledge of the occurrence and distribution of TTX in the marine environment where the edible bivalves grow is important for maintaining seafood safety, as the toxin is heat-stable and remains potent even after cooking. Therefore, in this study, 264 bivalve samples collected in 2019 and 2021 from 17 sites along the Swedish west coast were analyzed with LC-MS/MS to search for TTX. The study explores the hypothesis of TTX presence in Swedish marine waters, outlines the sample screening strategy and objectives, and reports no evidence of TTX presence in Swedish bivalve shellfish (≥7.8 µg/kg) based on the analyzed samples and the time periods in which the studied samples were collected. Full article

Natural wetlands are critical water quality regulators, especially in developing tropical countries. The Lubigi wetland is a large urban wetland in Kampala, the largest city in Uganda in Africa. We studied whether stormwater discharge and wastewater effluent from a nearby stormwater channel and a sewage treatment plant in the western part of the city were cleaned as they flowed through the wetland. Despite the significant pollution, the wetland removed ammonium-nitrogen, orthophosphate, and particulate nutrients during both seasons, achieving removal rates ranging from 50 to 60% for orthophosphate but only 20–40% for ammonium-nitrogen. Overall, seasonal differences in loads and retention rates of nutrient and organic matter inputs were minimal. Interestingly, the wetland mostly released nitrate and nitrite during water passage through the wetland, most likely due to the mineralization of organic nitrogen and agricultural run-off during rainy events in the wet season. However, the limited capacity of the sewage treatment plant and untreated stormwater discharge from the Nsooba main channel reduced the wetland’s ability to clean water. The insufficient carrying capacity of the treatment plant and the release of untreated sewage into the wetland significantly impact the self-purification capacity of the Lubigi wetland. Thus, the concept of Nature-Based Solutions is ineffective if the wetland systems are overloaded. Full article

Background/Objectives. The paediatric population is a heterogenous group that is known to be a therapeutic orphan despite the recent incentives to promote the development of children’s formulations. Especially in low and middle-income countries, there is still a worldwide shortfall for the treatment and prevention of a variety of paediatric conditions. In this context, we developed a formulation specifically intended to administer metronidazole to paediatric patients using basic and low-cost excipients and with a simple set-up method. Methods. Various mixtures of excipients were prepared to obtain a suitable metronidazole liquid formulation at a concentration of 250 mg/5 mL. The best formula was tested for its quality and stability, assessing the uniformity of content, the pH, and the dispersion quality. We evaluated the stability of the preparation for 180 days at room temperature (25 +/− 2 °C), in a thermostatic oven (40 +/− 2 °C), and in a fridge (4 +/− 2 °C). Results. The tests performed gave excellent results. No variation greater than 10% was detected in the metronidazole concentration or in pH values after 180 days regardless of the temperature conditions during storage. Moreover, the microscope analysis confirmed the absence of significant differences over time. Conclusions. The results were consistent in different environmental conditions, ensuring the possibility of using the formulation even in those tropical countries where is not always possible to guarantee the conservation of medicines in controlled conditions. Moreover, the simple composition and easy preparation procedure make it possible to produce the suspension in any context, ensuring the quality of the finished product. Full article