Rainforest Region Research Articles

Environmental Factors Associated With Loa loa Microfilaria Prevalence and Intensity in Diverse Bioecological Zones of Cameroon

Loiasis (African Eye Worm) is a filarial infection caused by Loa loa and transmitted by Chrysops vectors, which are confined to the tropical rainforests of Central and West Africa. Loiasis is a major impediment to control and elimination programmes that use the drug ivermectin due to the risk of serious adverse events. There is an urgent need to better refine and map high-risk communities. This study aimed to quantify and predict environmental factors associated with loiasis across five bioecological zones in Cameroon. The L. loa microfilaria (mf) prevalence (%) and intensity (mf number/ml) data from 42 villages within an Equatorial Rainforest and Savannah region were examined in relation to climate, topographic and forest-related data derived from satellite remote sensing sources. Differences between zones and regions were examined using nonparametric tests, and the relationship between L. loa mf prevalence, mf intensity, and the environmental factors using polynomial regression models. Overall, the L. loa mf prevalence was 11.6%, L. loa intensity 927.4 mf/ml, mean annual temperature 23.7°C, annual precipitation 2143.2 mm, elevation 790 m, tree canopy cover 46.7%, and canopy height 19.3m. Significant differences between the Equatorial Rainforest and Savannah region were found. Within the Equatorial Rainforest region, no significant differences were found. However, within the Savannah region, significant differences between the three bioecological zones were found, and the regression models indicated that tree canopy cover and elevation were significant predictors, explaining 85.1% of the L. loa mf prevalence (adjusted R2 = 0.851; p<0.001) and tree cover alone was significant, explaining 58.1% of the mf intensity (adjusted R2 = 0.581; p<0.001). The study highlights that environmental analysis can help delineate risk at different geographical scales, which may be practical for developing larger scale operational plans for mapping and implementing safe effective interventions.

Soil Water Variation Due to Grass Water Uptake

Shallow landslide is the phenomenon of slope collapse frequently occurring in tropical rainforest regions such as Malaysia based on geotechnical problem. This paper aims to determine the effects of grass on the shallow slope’s stability in terms of the variability of soil moisture, and to establish 1D suction of soil moisture due to grass water uptake. Moisture variations were used to compare the moisture content with time using GID and Fotran code tools. Based on the literature review findings, numerical simulation modelling was applied to achieve the most suitable condition for replicating grass water uptake within the soil slope. Six types of grasses were used in this research. The correlation between numerical simulation results is appropriate for these six types of grasses, but only Indropogon Gayanus grass with field monitoring results was achieved for validation. This paper assessed slope stability due to the influence of six types of grasses induced suction. The long grassroots are special between both kinds of grass, ranging from 0.3048 m to 4.000 m. This work gives a clear belief that Axonopus Compressus grass extracts water much faster than other grasses and is useful in preserving unsaturated soil stability.

Farmers’ Knowledge and Perception on CommonBeans Production Constraints and their Mitigation Methods in the Humid Rainforest and Highland Savanna of Cameroon

Background: Common beans, Phaseolus vulgaris is one of the most important plant protein sources in many African countries including Cameroon. It is a major source to smallholder farmers and some large-scale farmers. Common beans also fixes atmospheric nitrogen in symbiosis with rhizobia thus improving soil fertility. Despite the importance of this major food and cash crop, its production in Cameroon is constrained by several abiotic and biotic factors. Therefore it was hypothesized that bean farmers in the study regions have knowledge on; (1) the various factors that hamper bean production; (2) the planting periods/seasons that the various constraints are more important; (3) they have their own indigenous methods of mitigating these constraints but would prefer more appropriate methods if available.
 Aims: To document when farmers plant beans,how they handled the crop when matured, and if they faced problems with rot/mould, insects orany other constraints in their beans and how they manage these problems.
 Study Design: Random interviewing of beans farmers.
 Place and Duration of Study: Interviewed farmers in Buea and Dschang of the humid rainforest and highland agro-ecological zones of Cameroonrespectively from January 2017 to December 2017.
 Methodology: A semi-structural questionnaire was administered to 519 randomly selected bean farmers in two agro-ecological zones; the humid rainforest and highland savanna. A total of 163 from Bueain the south west (humid rainforest) and 356 from Dschang in the west (highland savanna) were randomly interviewed to document the farmers’ perceptions on various constraints hampering beansproduction, when these are most limiting and the various methods they use to mitigate them.
 Results: Farmers in both agro-ecological zones lacked adequate land surface area for bean production and suffered from low yields. In the highland savanna or west region, 166 (45.98%) and 119 (75.32%) in the humid rainforest or south west region grew beans in farms of sizes <1Ha. Only 2 (1.27%) of bean farmers in the South West and 35 (9.69%) in the West produced beans on farms >2Ha. Most farmers in the west 267 (73.96%) and 139 (87.97%) in the south west produced only 1-3 bags of 50kg each of beans/ha.The farmers faced problems with mold/rot and insect pests; the mold/rot was the most nagging for beans that matured during the rainy season while insect pests was the major constraint for the dry season beans. The mold/rot was controlled mainly by the adjustment of the planting dates of beans while different types of insecticides were used against the insect pests. Farmers also face problems in having adequate/appropriate staking materials for the climbing or indeterminate bean varieties.
 Conclusion: Considering that farmers face the actual daily challenges of bean production. Their knowledge and perceptions of the production constraints of this crop are quintessential and should count in defining research priorities aimed at mitigating the problems in order to increase beans production. Therefore, there is need for research to test and/or validate these farmers knowledge and perceptions about bean production constraints as a prelude to vulgarizing the effective control/management options.

Rainforest tourism: a systematic review of established knowledge and gaps in research

ABSTRACT Rainforests provide exceptional spaces for nature-based tourism activities attracting large numbers of visitors. Simultaneously, tourism activities may create environmental, social and economic impacts that require management in order to conserve sensitive rainforest environments. Rainforest tourism constitutes a travel sector that receives growing interest worldwide. This study presents a timely review of current knowledge and research gaps in a new conceptual model to give recommendations for a future research agenda. Through a systematic quantitative review, the study identified 48 peer-reviewed journal articles addressing conservation and management topics (33), followed by visitor-related research (23), impacts (10), and finally community and stakeholder research (3) of rainforest tourism, published between 1975 and 2019. The majority of research focused on management issues relating to policy development, planning, education and conservation measures. A strong geographic bias was noted with very limited research available for rainforest regions in Africa and Asia. Future research should be concerned with expanding and linking rainforest research across countries, and filling knowledge gaps around visitor monitoring, specific impacts and causes, and the complexity of community and stakeholder involvement in managing impacts. Protocols may need to be established to facilitate the design and delivery of standardised research approaches across the globe.

Description of a new species of emDinidor/em Latreille (Hemiptera: Dinidoridae) from the Brazilian Amazon Rainforest, and new records of emD. saucius/em Stål.

Dinidor jograziae sp. nov., is described. The new species can be recognized by the relatively shorter mandibular plates which do not come in contact with each other anterior to the clypeus, by the dark brown hemelytral membranes, with darker, reticulate veins, and by having a relatively large portion of the connexiva exposed. We provide high-resolution photographs of important characters such as the head, pronotum, and the male and female external genitalia. We also provide new locality records for D. saucius from southern and southeastern Brazil, including the Atlantic Rain Forest region in the states of Rio de Janeiro, Santa Catarina and São Paulo.

Rainfall distribution in a region of Amazon rainforest in the north of Mato Grosso

Rainfall predominantly influences economic activity in northern of MatoGrosso. The scarcity of rainfall limits agricultural production, and its excess hinders the flow of production on back roads. These obstacles impose the need for greater knowledge of rainfall in distant regions of the state, such as Paranorte, in Juara-MT. This study aimed to identify the beginning and end of the rainy season, as well as the frequency and duration of dry days, besides to investigate causal relationships of rainfall with ENSO (El Niño de Oscillation Sul) phenomena. Methods based on rainfall quantity and continuity were adopted. The results showed that in Paranorte, the accumulated annual precipitation varies between 2322 and 2720 mm. The months of the year are divided into a dry period (June, July and August), a period of low rainfall (May and September - ≈ 80 mm) and a period of high rainfall (October, November, December, January, February, March and April, with 214 to 464 mm). Prolonged droughts occur most often at the beginning (September) and end (May) of the rainy season. In turn, ENSO phenomena influence rainfall only in spring.

Biochemical and phylogenetic characterization of the wastewater tolerant Chlamydomonas biconvexa Embrapa|LBA40 strain cultivated in palm oil mill effluent.

The increasing demand for water, food and energy poses challenges for the world´s sustainability. Tropical palm oil is currently the major source of vegetable oil worldwide with a production that exceeds 55 million tons per year, while generating over 200 million tons of palm oil mill effluent (POME). It could potentially be used as a substrate for production of microalgal biomass though. In this study, the microalgal strain Chlamydomonas biconvexa Embrapa|LBA40, originally isolated from a sugarcane vinasse stabilization pond, was selected among 17 strains tested for growth in POME retrieved from anaerobic ponds of a palm oil industrial plant located within the Amazon rainforest region. During cultivation in POME, C. biconvexa Embrapa|LBA40 biomass productivity reached 190.60 mgDW • L-1 • d-1 using 15L airlift flat plate photobioreactors. Carbohydrates comprised the major fraction of algal biomass (31.96%), while the lipidic fraction reached up to 11.3% of dry mass. Reductions of 99% in ammonium and nitrite, as well as 98% reduction in phosphate present in POME were detected after 5 days of algal cultivation. This suggests that the aerobic pond stage, usually used in palm oil industrial plants to reduce POME inorganic load, could be substituted by high rate photobioreactors, significantly reducing the time and area requirements for wastewater treatment. In addition, the complete mitochondrial genome of C. biconvexa Embrapa|LBA40 strain was sequenced, revealing a compact mitogenome, with 15.98 kb in size, a total of 14 genes, of which 9 are protein coding genes. Phylogenetic analysis confirmed the strain taxonomic status within the Chlamydomonas genus, opening up opportunities for future genetic modification and molecular breeding programs in these species.

Amazon forest cover change mapping based on semantic segmentation by U-Nets

Deforestation remains a major concern with regard to climate change and the maintenance of biodiversity. Meanwhile, the development of new image processing techniques and the broad availability of high spatiotemporal resolution satellite imagery provide an unprecedented setup for the development of effective and scalable forest cover change monitoring systems. This is especially relevant in regions with large forested areas with high rates of deforestation, such as in the region of the Brazilian Amazon rainforest. In this context, existing forest cover change monitoring methods are based on a combination of visual inspection, spectral profiles, statistics, and machine learning techniques, which offer alternative backbones to deal with deforestation monitoring. Given the recent advances in the field of image processing by Fully Convolutional Neural Networks (FCNs), the objective of this study is to evaluate the performance of the U-Net architecture for the mapping of forest cover aimed at identifying deforestation polygons in multi-temporal satellite imagery. To this end, 10-m resolution imagery from the Sentinel-2 satellite covering portions of the Legal Amazon region were employed. The U-Net could identify and draw polygons of forest areas and forest fragments with high accuracy (0.9470), precision (0.9356), recall (0.9676), and F1-score (0.9513), thus outperforming largely applied and well-know supervised and unsupervised image classification methods. The results indicate and we further discuss that U-Nets have the potential to run as the backbone for efficient forest cover change monitoring initiatives and support the deployment of near real-time deforestation warning systems.

Tree recruitment failure in old‐growth forest patches across human‐modified rainforests

Abstract Land‐use change threatens biodiversity in tropical landscapes, but its impact on rainforest regeneration remains poorly known. In fact, the landscape‐scale patterns driving the diversity of regenerating plants within forest fragments have been rarely explored, and we are uncertain whether such drivers vary across regions with different land‐use change patterns. We assessed the effect of landscape composition (forest cover and matrix openness) and configuration (forest patch density) on species diversity of sapling assemblages (trees ≥30 cm height and <1 cm diameter) in old‐growth forest fragments from three Mexican rainforest regions with different disturbance levels (n = 20 landscapes per region). We separately assessed old‐growth forest specialists (OGS) and forest generalist (FG) species to test the hypotheses that: (a) OGS species show recruitment limitation (‘loser’ species), and can therefore be negatively impacted by landscape changes, especially by forest loss and matrix openness in more deforested regions; and (b) FG species can regenerate and even proliferate in more disturbed landscapes (‘winner’ species). We recorded ~24,000 plants from 415 species. Landscape composition showed stronger effects than landscape configuration. The diversity of OGS species generally decreased in more deforested landscapes dominated by open matrices, and FG species followed the opposite response, especially in the regions with high‐to‐intermediate degree of disturbance. Overall, forest fragmentation (patch density) showed weak or no effects on species diversity, especially after controlling for forest cover effects (i.e. fragmentation per se). In contrast to the fragmentation threshold hypothesis, the effect of fragmentation was independent of the regional context. Moreover, FG species were affected by landscape attributes operating at larger scales than OGS species. Synthesis. Our findings support our hypotheses, and suggest that forest loss and matrix openness, not fragmentation per se, can cause the recruitment failure of tree assemblages in highly deforested rainforests. This can be related to source and dispersal limitation in more deforested landscapes with treeless matrices. Therefore, to promote the regenerative potential (resilience) of forest patches in human‐modified tropical landscapes, conservation programs should focus on preventing forest loss (even the smallest forest patches) and improving matrix quality with treed elements, particularly in highly deforested tropical regions.

Effects of mercury at field estimated concentration in brain of Bombus atratus (Hymenoptera: Bombini)

Although mercury neurotoxic effects are well known in several species, it is poorly studied in bees. Mercury contamination is increasing in several regions of the Brazilian Amazon Rainforest due to illegal and indiscriminate gold mining. Therefore, this study aimed to evaluate the effects of mercury (Hg) in brain Kenyon cells of foraging workers of Bombus atratus exposed to an average concentration (110 ppb) found in pots of honey from native bees of South America and Australia. Twenty forager workers were collected in the field (23° 34′ S 47° 31′ W), divided into control (n = 10) and exposed (n = 10) groups, and individually kept in special boxes for 48 h. For the exposed group, we offered Hg solution (at 110 ppb) ad libitum, while for the control group we offered water, and for both sucrose syrup at 70%. After the exposure time, the bees were crio-anesthezied at 4 °C. Brains were dissected and processed for morphological, morphometric, and histochemical analyses. Morphological results showed that the Kenyon cells of the Hg-exposed group presented both cytoplasmic vacuolization and nuclear pyknosis, which indicate cell death. These findings were corroborated by the acridine orange staining. Hg exposure also induced significant nuclear chromatin compaction in Kenyon cells. The calyces and peduncles of the mushroom bodies showed disorganization and vacuolization. In summary, these changes may imply in a severe impairment of the cognitive abilities of the bees, which could lead them to the loss of many tasks, such as foraging or even nest founding by the queen.

The Zygoptera/Anisoptera ratio as a tool to assess anthropogenic changes in Atlantic Forest streams

The changes in land use caused by human activities have directly impacted aquatic ecosystems, making these environments some of the most threatened places on the planet. It is increasingly necessary and urgent to develop tools to identify and assess the effects of human impacts on ecosystems and biodiversity. This study aimed to evaluate whether the Zygoptera/Anisoptera ratio can be an effective tool to measure ecological changes in Atlantic Forest streams. Adult Odonata were collected in 42 streams. An environmental integrity index was used as a measure of environmental change. The Zygoptera/Anisoptera ratio was efficient in classifying the state of preservation of streams; therefore, habitats with a proportion equal to or greater than 67 and 52% of richness and abundance of the suborder Anisoptera can be considered altered. Meanwhile, streams representing a proportion of 54 and 67% of richness and abundance of the suborder Zygoptera can be considered little altered or preserved. The proportions of responses were close to the proposals for streams in the Amazon rainforest region. The ease of identifying the specimens in the different suborders of Odonata is practical, enabling the implementation of participatory monitoring with quick responses for monitoring in the aquatic ecosystems assessed in the region. It is important to test the Zygoptera/Anisoptera ratio for a broader validation in biomes where this evaluation has not yet been carried out. In the future, this will enable the implementation of networks for monitoring the integrity of aquatic environments quickly, effectively and at a low cost.

Beyond patch size: The impact of regional context and habitat quality on three endangered primates

Deforestation has carved tropical forest landscapes into millions of different-sized patches worldwide. Research has focused on the effect of patch size on biodiversity, while neglecting patch quality effects and leaving geographic and interspecific variance to patch attributes largely unexamined. Here, we assess how patch size and quality affect the encounter rate (ER) and immature-to-female ratio (IFR) of three endangered primates – Mexican mantled howler monkey (Alouatta palliata mexicana), black howler monkey (Alouatta pigra), and spider monkey (Ateles geoffroyi) – in three rainforest regions with different forest cover. ER of spider monkeys in the best preserved region (50% forest cover) was positively related to both patch size and quality (i.e., species richness of top food species). ER of mantled howlers in the 17% forest cover region was also positively related to patch size. Yet, both ER and IFR of black howlers in the 50% forest cover region and mantled howlers in the 5% forest cover region were mainly related to patch quality. Our results demonstrate that conservation actions in human-modified landscapes must go beyond considering the effect of patch size, as animal populations can be better predicted by patch quality in some regions.

Hazard Assessment and Implementation Strategies for Mitigating of Flood and Erosion in Nigeria

There are notching unresolved issues and environmental hazards traceable to flood and erosion in major rural areas and notable communities in Nigeria. Researchers’ efforts on erosion control and flood mitigation have not yielded notable fruits due to inadequate planning and implementation strategies. Maintenance of roads and other infrastructures are the bed rock of any development round the globe. This paper assessed recent occurrence of flood and erosion. The study examined the causes, urban and regional planning of the affected area, construction practices, damages and maintenance practices. Questionnaires, field study and interview of experts were wont to elicit information from people within the affected location, officials from state and native government agencies charged with rehabilitation of affected areas. The research finding revealed that there are inadequate drainage systems, lack of enforcement of plan, corruptions, failure of systems, poor supervision, construction malpractices, lackadaisical attitude and lack of maintenance culture. Implementation strategies were highlighted to avert flood and erosion ravaging several areas of the country. The paper concluded that stakeholders, researchers, engineers should partner with government agencies within the planning, construction, management and maintenance of rural and concrete drainages for adequate funding and sustainable construction. It is recommended that strategies for alleviating flood and erosion should be implemented supported latest technology for sustainable infrastructural development. Periodic hazard assessment should be planned in various geopolitical zones especially Lagos, Niger delta and rain forest region of Nigeria. Land use control, landscape maintenance, weather stations, proper enforcement of construction works consistent with plan should be strategically put in situ for effective monitoring and alleviation of flood and erosion in Nigeria.

Characterizing water vapour concentration dependence of commercial cavity ring-down spectrometers for continuous on-site atmospheric water vapour isotope measurements in the tropics

Abstract. The recent development and improvement of commercial laser-based spectrometers have expanded in situ continuous observations of water vapour (H2O) stable isotope compositions (e.g. δ18O and δ2H) in a variety of sites worldwide. However, we still lack continuous observations in the Amazon, a region that significantly influences atmospheric and hydrological cycles on local to global scales. In order to achieve accurate on-site observations, commercial water isotope analysers require regular in situ calibration, which includes the correction of H2O concentration dependence ([H2O] dependence) of isotopic measurements. Past studies have assessed the [H2O] dependence for air with H2O concentrations of up to 35 000 ppm, a value that is frequently surpassed in tropical rainforest settings like the central Amazon where we plan continuous observations. Here we investigated the performance of two commercial analysers (L1102i and L2130i models, Picarro, Inc., USA) for measuring δ18O and δ2H in atmospheric moisture at four different H2O levels from 21 500 to 41 000 ppm. These H2O levels were created by a custom-built calibration unit designed for regular in situ calibration. Measurements on the newer analyser model (L2130i) had better precision for δ18O and δ2H and demonstrated less influence of H2O concentration on the measurement accuracy at each concentration level compared to the older L1102i. Based on our findings, we identified the most appropriate calibration strategy for [H2O] dependence, adapted to our calibration system. The best strategy required conducting a two-point calibration with four different H2O concentration levels, carried out at the beginning and end of the calibration interval. The smallest uncertainties in calibrating [H2O] dependence of isotopic accuracy of the two analysers were achieved using a linear surface fitting method and a 28 h calibration interval, except for the δ18O accuracy of the L1102i analyser for which the cubic fitting method gave the best results. The uncertainties in [H2O] dependence calibration did not show any significant difference using calibration intervals from 28 up to 196 h; this suggested that one [H2O] dependence calibration per week for the L2130i and L1102i analysers is sufficient. This study shows that the cavity ring-down spectroscopy (CRDS) analysers, appropriately calibrated for [H2O] dependence, allow the detection of natural signals of stable water vapour isotopes at very high humidity levels, which has promising implications for water cycle studies in areas like the central Amazon rainforest and other tropical regions.

Microclimates hold the key to spatial forest planning under climate change: Cyanolichens in temperate rainforest.

There is deepening interest in how microclimatic refugia can reduce species threat, if suitable climatic conditions are maintained locally, despite global climate change. Microclimates are a particularly important consideration in topographically heterogeneous landscapes, while in some habitats, such as forests and woodlands, microclimates are also extremely labile and affected by management practices that could consequently be used to offset climate change impact. This study explored a conservation priority guild-cyanolichen epiphytes in temperate rainforest-quantifying the niche response to macroclimate, and landscape or woodland stand structures that determine the microclimate. Based on epiphyte survey in a core region of European temperate rainforest (western Scotland), a 'random forest' machine-learning model confirmed a strong cyanolichen response to summer dryness, as well as the effects of distance to running water, topographic heatload and tree species identity, which modify the local moisture regime and/or lichen growth rates. By quantifying this response to macroclimate, landscape and stand structures, it was possible to estimate an extent to which woodland may be expanded in the future, to offset a negative effect of increasing summer dryness projected through to the 2080s. Using current policy as a yardstick, sufficient woodland expansion could be delivered relatively quickly for median impacted sites, but with times to woodland delivery extending over 10, 20 and 25years for sites at the 75th, 90th and 95th percentiles of cyanolichen decline. Furthermore, the extent of new woodland required, and delivery times, increase almost threefold on average, as new woodland becomes distributed over wider riparian zones. These contrasting implications emphasize an urgent need for afforestation that achieves targeted spatial planning responsive to microclimates as refugia.

Prediction of Future Natural Suitable Areas for Rice under Representative Concentration Pathways (RCPs)

Extreme temperature events, which are part of global climate change, are a growing threat to crop production, especially to such temperature-sensitive crops as rice. As a result, the traditional rice-growing areas are also likely to shift. The MaxEnt model was used for predicting the areas potentially suitable for rice in the short term (2016–2035) and in the medium term (2046–2065) and under two scenarios developed by the Intergovernmental Panel on Climate Change, namely representative concentration pathway (RCP) 4.5 (the intermediate scenario) and RCP 8.5 (sometimes referred to as the worst-case scenario). The predictions, on verification, were seen to be highly accurate: the AUC—area under the curve—value of the MaxEnt model was > 0.85. The model made the following predictions. (1) Areas highly suitable for rice crops will continue to be concentrated mainly in the current major rice-production areas, and areas only marginally suitable will be concentrated mainly in the rainforest region. (2) Overall, although the current pattern of the distribution of such areas would remain more or less unchanged, their extent will mainly decrease in the subtropics but increase in the tropics and in high-latitude regions. (3) The extent of such areas will decrease in the short term but increase in the medium term.

Big wheel keep on turnin': Linking grower attitudes, farm management, and delivery of avian ecosystem services

Growers may be more likely to adopt wildlife-friendly practices if they perceive that beneficial species are present and conservation actions are successful. At the same time, a farm's landscape and regional context may influence whether biodiversity, including wild birds, are likely to provide ecosystem services or disservices. Here, across two Bird Conservation Regions in the western USA, we assessed a feedback loop that links growers' attitudes towards birds, farming practices, and bird assemblages' hypothesized impacts. To do so, we paired a grower questionnaire survey, bird point count surveys, and farm management and landscape classifications. We found that growers generally exhibited more positive attitudes towards raptors than songbirds and allies (e.g., flycatchers, woodpeckers, hummingbirds). Attitudes towards raptors were more positive when farms were embedded in more natural landscapes and had greater proportions of nonnative birds. Growers held more positive attitudes towards songbirds and allies related to production (yields, crop quality, insect control) when their farms were in the Northern Pacific Rainforest region and were embedded in more natural landscapes. Growers' attitudes towards songbirds and allies related to disease/infrastructure (food safety, animal disease, building/machinery damage, vertebrate control) were more positive in the Northern Pacific Rainforest region as landscapes became more natural, but these relationships did not hold for Coastal California. However, growers' attitudes towards birds were mostly unrelated to the practices used on the farm. Understanding these feedback loops is crucial to increasing uptake of and retention in conservation programs for rapidly declining farmland bird communities.

Cervical cancer mortality in Peru: regional trend analysis from 2008\u20132017

BackgroundCervical cancer is the third leading cause of cancer-related death among Latin American women. Peru has the sixth highest mortality rate for cervical cancer in the region with regional variations. We aimed to determine overall and regional cervical cancer mortality rates and trends in Peru between 2008 and 2017.MethodsWe performed an ecological study on the number of deaths by cervical cancer in Peru. Deaths were extracted from the Peruvian Ministry of Health mortality database. Age-standardized mortality rates (ASMR) were estimated per 100,000 women-years using the world standard Segi population. We computed mortality trends using the Joinpoint regression program, estimating the annual percent change (APC). For spatial analysis, GeoDA software was used.ResultsPeru showed downward trends in the last decade (from 11.62 in 2008 to 9.69 in 2017 (APC = − 2.2, 95% CI: − 4.3, − 0.1, p < 0.05). According to regional-specific analysis, the highest ASMR was in the rainforest region, although this declined from 34.16 in 2008 to 17.98 in 2017 (APC = − 4.3, 95% CI: − 7.2, − 1.3, p < 0.01). Concerning spatial analysis and clustering, the mortality rates from 2008 to 2017 showed a positive spatial autocorrelation and significant clustering (Moran’s I: 0.35, p < 0.001) predominantly in the neighboring North-East departments (Loreto, Ucayali, and San Martin).ConclusionsAlthough mortality trends in the entire population are decreasing, mortality rates remain very high, mainly in the rainforest region. Our results encourage a need for further development and improvement of the current health care delivery system in Peru.

Chemical composition and in vitro biological studies of volatile oils from Nigerian bee propolis

Volatile oils of propolis obtained from Ondo (Ondo town) and Osun (Ile-Ife) States in Rain forest region of southwest Nigeria were extracted using the hydrodistillation method. The oils were analysed on GC/MS and investigated for DPPH scavenging activities, antibacterial potentials, and inhibitory activities on lipase and alpha glucosidase enzymes. Spectrophotometric methods were used for the DPPH scavenging and enzyme’ inhibitions assays while the agar well diffusion method was employed for the antibacterial test. GC/MS analysis of essential oils obtained from Ondo (BPO) and Ile-Ife (BPI) indicated 80 (97.82%) and 66 (99.31%) compounds respectively. Upon classification, both oils were rich in monoterpenes, sequisterpenes and non-isoprenoid hydrocarbons. Principal chemical components of BPO included trans-α-bergamotene (9.08%), α-copaene (5.83%), cadina-1,4-diene (4.04%), 2-methyl-5-propionylfuran (3.43%), 1,5,9,9-tetramethyl-1,4,7-cycloundecatriene (3.52%), benzaldehyde (2.98%), sulcatone (2.95%), γ-muurolene (2.51%), caryophyllene (2.40%), α-bisabolol (2.09%), α-eudesmol (2.07) and α-curcumene (2.06%) while those of BPI were trans-α-bergamotene (10.14%), citral (5.44%), α-copaene (5.25%), cadina-1,4-diene (5.09%), melonal (3.69%), sulcatone (3.56%), farnesol (2.71%), 3,5,9-trimethyl-deca-2,4,8-trien-1-ol (2.66%), α-curcumene (2.64%), 1,5,9,9-tetramethyl-1,4,7-cycloundecatriene (2.20%), and α-muurolene (2.20%). Both oils inhibited α-glucosidase and had DPPH scavenging activities better than the standards, however, anti-lipase activity was observed for BPI only. The oils also demonstrated broad spectrum of antibacterial activities. The volatile components of Nigerian bee propolis are being investigated for the first time, and the plethora of biological activities resulting from their diverse chemical composition showed that bee propolis could be a potential source for drug discovery.

The SARS-COV-2 outbreak around the Amazon rainforest: The relevance of the airborne transmission.

At the beginning of the SARS-COV-2 outbreak in Brazil, there was a striking difference between the contamination rate in the Amazonian States and the South and the Southeast States. The regions near the Amazon rainforest presented much higher and faster contaminations. This paper attempts to explain this phenomenon through a global analysis of the COVID-19 epidemic in Brazil. It also investigates the relationship between climate conditions and airborne transmission with the evolution of contagion in the Amazonian states. The method of investigation of the spread of SARS-COV-2 in these different macro-environments was based on the analysis of three extensive daily official databases on the number of deaths, the percentage of adherence of the populations to the restriction policies, and the local climatic conditions. Besides, the social conditions in those States were also taken into account. Then, it was compared the epidemiologic results for States with very different climatic characteristics and that had adopted, almost simultaneously, similar social isolation measures. However, all these analyses were not able to explain the remarkable difference in the evolution of the pandemic among Brazilian regions. So, it was necessary to invoke airborne transmission, facilitated by the very high air humidity, as a decisive factor to explain the faster evolution of contagion in the rainforest region. Air humidity seems to be the most important climatic factor in viral spreading, while usual ambient temperatures do not have a strong influence. Another very important result of this analysis was the observation that the onset of collective immunity may have been achieved with a contamination rate of about 15% of the Amazonian population.