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Natural infection with Trypanosoma cruzi in three species of non-human primates in southeastern Mexico : a contribution to reservoir knowledge
No full textThe mechanisms of infection and dispersion of Trypanosoma cruzi among animals, especially in the sylvatic environment, are still not entirely clear, and various aspects of the transmission dynamics of this parasite in the sylvatic environment are still unknown. T. cruzi is a parasite with a great biological and genetic diversity that infects a wide variety of hosts, therefore, transmission cycles of this parasite are complex. The objective of this study was to determine the prevalence of T. cruzi infection and analyze the genetic variability of the discrete typing units (DTUs) of the parasite in three non-human primate species (Alouatta palliata, Alouatta pigra, and Ateles geoffroyi) in southeastern Mexico. A total of one hundred sixty-four serum samples (42 samples of A. pigra, 41 samples of A. palliata (free-ranging) and 81 samples of A. geoffroyi (hosted in care centers)) were analyzed for the detection of anti -T. cruzi antibodies by ELISA assays. The seroprevalence of infection was 23.39% in A. palliata, 21.40% in A. pigra and 16.27% in A. geoffroyi. Additionally, presence of parasite DNA was assessed by PCR, and the identification of DTUs was performed by real-time PCR coupled to High Resolution Melting (qPCRHRM). Different DTUs (TcI, TcII, TcIII, TcV and TcVI) were found in the analyzed monkeys. In addition, infection of monkeys was not associated with age or gender, but it was associated with the species. This study reveals the risk of infection in the study area and that the different DTUs of the parasite can coexist in the same habitat, indicating that T. cruzi transmission in the study area is very complex and involves many ecological factors. However, there is a need for long-term studies of host-parasite interactions to provide a solid understanding of the ecology of these species and to understand the dispersion strategies of T. cruzi
A modelling-based assessment of suspended sediment transport related to new damming in the Red River basin from 2000 to 2013
No full textThe Red River is an Asian river system strongly affected by global changes. This paper aims to characterize and quantify the suspended sediment flux (SF) over the basin under the influences of short-term climate variability and dam constructions. SF was evaluated at the outlets of main tributaries and along the main course of the Red River from 2000 to 2013 based on daily simulations from a modelling study. A reference scenario (without dams) was carried out to disentangle the impacts of short-term climate variability and damming by comparing to actual conditions. Without dams (reference scenario), the basin would generate 106.9 Mt yr(-1) of SF to the downstream delta from 2000 to 2013, with a specific sediment yield (SSY) of 778.8 t km(-2) yr(-1). However, under the impacts of short-term climate variability and dams, the mean annual SSY decreased to 84.5 t km(-2) yr(-1). At the outlet of the basin, the annual mean SF of 2008-2013 (after new dam constructions) got reduced by 90% (10% related to short-term climate or atmospheric variability and 80% to dam constructions) compared to the reference scenario (without dams) during 2000-2007. The Thao tributary is the most sensitive to short-term climate variability while the Da tributary is mostly affected by the huge-capacity dams. Mean annual retentions of sediment by dams ranged from 7.1 to 111.0 Mt yr(-1). Simple rating curves between monthly mean discharge (Q) and SF were established for estimating SF at the outlet of the tributaries and the Red River. High soil erosion (above 2000 t km(-2) yr(-1)) occurred in the middle Thao and the lower Da tributaries. Precipitation, slope and agriculture practices are the key influence factors for soil erosion in the basin
Thyroid doses to French Polynesians resulting from atmospheric nuclear weapons tests : estimates based on radiation measurements and population lifestyle data
No full textThyroid doses were estimated for the subjects of a population-based case-control study of thyroid cancer in a population exposed to fallout after atmospheric nuclear weapons tests conducted in French Polynesia between 1966 and 1974. Thyroid doses due to (1) intake of I-131 and of short-lived radioiodine isotopes (I-132, I-133, I-135) and Te-132, (2) external irradiation from gamma-emitting radionuclides deposited on the ground, and (3) ingestion of long-lived Cs-137 with foodstuffs were reconstructed for each study subject. The dosimetry model that had been used in 2008 in Phase I of the study was substantially improved with (1) results of radiation monitoring of the environment and foodstuffs, which became available in 2013 for public access, and (2) historical data on population lifestyle related to the period of the tests, which were collected in 2016-2017 using focus-group discussions and key informant interviews. The mean thyroid dose among the study subjects was found to be around 5 mGy while the highest dose was estimated to be around 36 mGy. Doses from I-131 intake ranged up to 27 mGy, while those from intake of short-lived iodine isotopes (I-132, I-133, I-135) and Te-132 ranged up to 14 mGy. Thyroid doses from external exposure ranged up to 6 mGy, and those from internal exposure due to Cs-137 ingestion did not exceed 1 mGy. Intake of I-131 was found to be the main pathway for thyroid exposure accounting for 72% of the total dose. Results of this study are being used to evaluate the risk of thyroid cancer among the subjects of the epidemiologic study of thyroid cancer among French Polynesians
Climate and categories : two key elements for understanding the Mesoamerican hot-cold classification of illnesses and medicinal plants
No full textEthnopharmacological relevance: The concepts of health and illness, and their causes, are fundamental for understanding medicinal plant choice and use by traditional people. The hot-cold system is widespread in Mesoamerican traditional medicine and guides many therapeutic decisions. Aim of the study : This study explores a hypothesis that climate influences the hot-cold classification of illnesses and medicinal plants, and the perception of hazard of illnesses. In addition, we examine the classification categories within the system used in different regions of Mexico. Materials and methods: Studies from Mexico with quantitative and qualitative data on the hot-cold properties of medicinal plants and ailments were reviewed. The information was organized and then related to the climate type of the study areas. Results: In temperate climates, most diseases were considered cold, and hot medicinal plants were dominant. Conversely, in warm-tropical climates, hot diseases dominated, and the majority of medicinal plants were cold; however, this evidence was weaker. The perception of hazard was congruent with the number of illnesses for temperate climates. There were additional classification categories within the hot-cold system for diseases and medicinal plants, and they were expressed in different terms in Spanish, English, and indigenous languages. Although similar terms and categories were used in the classification of diseases and medicinal plants, they can differ conceptually and vary between places and cultures. Publications are sometimes unclear if the terms used are emic or etic. The basic principle of using plants with the opposite property of the disease does not always apply strictly. Conclusions: Climate appears to influence the hot-cold classification of diseases and medicinal plants in Mexico, and the system is not strictly dual. Improved knowledge of the hot-cold system is necessary to understand Mesoamerican medicinal plant use and culture
Mice immunization with Trypanosoma brucei gambiense translationally controlled tumor protein modulates immunoglobulin and cytokine production, as well as parasitaemia and mice survival after challenge with the parasite
No full textFighting trypanosomiasis with an anti-trypanosome vaccine is ineffective, the parasite being protected by a Variable Surface Glycoprotein (VSG) whose structure is modified at each peak of parasitaemia, which allows it to escape the host's immune defenses. However, the host immunization against an essential factor for the survival of the parasite or the expression of its pathogenicity could achieve the same objective. Here we present the results of mouse immunization against the Translationally Controlled Tumor Protein (TCTP), a protein present in the Trypanosoma brucei gambiense (Tbg) secretome, the parasite responsible for human trypanosomiasis. Mice immunization was followed by infection with Tbg parasites. The production of IgG, IgG1 and IgG2a begun after the second TCTP injection and was dose-dependant, the maximum level of anti-TCTP antibodies remained stable up to 4 days post-infection and then decreased. Regarding cytokines (IL-2, 4, 6, 10, INFγ, TNFα), the most striking result was their total suppression after immunization with the highest TCTP dose. Compared to the control group, the immunized mice displayed a reduced first peak of parasitaemia, a 100% increase in the time to onset of the second peak, and an increased time of mice survival. The effect of immunization was only transient but demonstrated the likely important role that TCTP plays in host-parasite interactions and that some key parasite proteins could reduce infection impac
Length-weight relationships of 19 fish species from two tropical artificial reservoirs (Manantali and Selingue) in Mali, West Africa
No full textLength-weight relationships (LWRs) were estimated for 19 fish species sampled from two artificial reservoirs (Manantali and Selingue) in Mali: Brycinus leuciscus, B. macrolepidotus, B. nurse, Chrysichthys auratus, C. nigrodigitatus, Coptodon zillii, Distichodus brevipinnis, D. rostratus, Hemichromis fasciatus, Hydrocynus forskahlii, Labeo coubie, L. senegalensis, Lates niloticus, Mormyrus rume, Sarotherodon galilaeus, Schilbe intermedius, S. mystus, Synodontis schall, S. sorex. The fish were collected between June 2002 and October 2003 during three experimental fishing campaigns using gillnets deployed overnight. All fish were measured (total length) to the nearest mm and weighed to the nearest g (total weight). Coefficients of determination of the LWRs (r²) were mostly high (> 0.9). The values of the allometry coefficient b ranged from 2.651 (Chrysichthys auratus) to 3.270 (Brycinus leuciscus). This study provides new information about LWRs of two fish species, which have been published but are not yet available in Fishbase (Distichodus brevipinnis and Mormyrus rume
Un refuge forestier menacé : la forêt d'altitude à Parinari du Mont Tonkoui en Côte d'Ivoire : évaluation de la biodiversité entomologique, botanique et ornithologique, valeurs de conservation du site
No full textGIS-based assessment of aquifer vulnerability using DRASTIC model and stable isotope : a case study on Essaouira basin
No full textGroundwater in the present study is defined as a sensitive contamination of fresh water to various pollutants that are made by human or natural elements. The research sought to measure the vulnerability of groundwater in the semi-arid regions and to identify sites where protection is likely needed by way of examining the resources relative to the sources of pollutants in the Meskala-Krimat sub-basin by using the DRASTIC model in the Geographic Information System (GIS) environment. The DRASTIC index resulting from the groundwater modeling that ranges between 114 and 191 were classified into three categories: low vulnerability which signifies 1.7% confidence level, moderate vulnerability which signifies 14.7% confidence level, and high vulnerability which signifies 83.7% confidence level. Analyzing this approach disclosed the electrical conductivity from the upstream part increased compared with the downstream part of the study area due to susceptibility to the high mineralization and leaching of Tidzi Diapir. In addition, the groundwater flow remained in the same direction from northeast to northwest and from northeast to southwest during the four campaigns 2007, 2018, 2019, and 2020. Stable isotope (H-2 and O-18) measurements indicate that the Atlantic rainfall is continuously recharging the watershed recharge areas. And so, the low values of tritium (H-3) in the groundwater signify that the fresh water in the Cenemano-Turonien aquifer is old. The present study proved that DRASTIC modeling using GIS is an effective technique in managing and protecting the vulnerable groundwater
A robust phylogenomic framework for the calamoid palms
No full textWell-supported phylogenies are a prerequisite for the study of the evolution and diversity of life on earth. The subfamily Calamoideae accounts for more than one fifth of the palm family (Arecaceae), occurs in tropical rainforests across the world, and supports a billion-dollar industry in rattan products. It contains ca. 550 species in 17 genera, 10 subtribes and three tribes, but their phylogenetic relationships remain insufficiently understood. Here, we sequenced almost one thousand nuclear genomic regions for 75 systematically selected Calamoideae, representing the taxonomic diversity within all calamoid genera. Our phylogenomic analyses resolved a maximally supported phylogenetic backbone for the Calamoideae, including several higher-level relationships not previously inferred. In-depth analysis revealed low gene tree conflict for the backbone but complex deep evolutionary histories within several subtribes. Overall, our phylogenomic framework sheds new light on the evolution of palms and provides a robust foundation for future comparative studies, such as taxonomy, systematics, biogeography, and macroevolutionary research
Use of mercury isotopes to quantify sources of human inorganic mercury exposure and metabolic processes in the human body
No full textThe pathways of human mercury (Hg) exposure are complex and accurate understanding of relative contributions from different pathways are crucial for risk assessment and risk control. In this study, we determined total Hg concentration and Hg isotopic composition of human urine, dietary components, and inhaled air in the Wanshan Hg mining area (MA), Guiyang urban area (UA), and Changshun background area (BA) to understand Hg exposure sources and metabolic processes in human body. At the three studied sites, total gaseous mercury (TGM) showed negative delta Hg-202 (-3.11 parts per thousand to + 1.12 parts per thousand) and near-zero Delta Hg-199 (-0.16 parts per thousand to + 0.13 parts per thousand), which were isotopically distinguishable from Hg isotope values of urine (delta Hg-202: -4.02 parts per thousand to -0.84 parts per thousand; Delta Hg-199: -0.14 parts per thousand to 0.64 parts per thousand). We observed an offset of -1.01 parts per thousand to -1.6 parts per thousand in delta Hg-202 between TGM and urine samples, and an offset of -1.01 parts per thousand to 0.80 parts per thousand in delta Hg-202 between rice and urine samples, suggesting that lighter isotopes are more easily accumulated in the kidneys and excreted by urine. We proposed that the high positive Delta Hg-199 in urine samples of UA was derived from fish consumption. The results of a binary mixing model based on Delta Hg-199 were compared with those from a classic dietary model. The results from the MIF binary model showed that fish consumption accounted for 22% of urine Hg in the families at UA, whereas fish consumption contributed limited Hg to MA and BA. This study highlighted that Hg isotopes can be a useful tracer in understanding the sources and fates of Hg in human bodies