Author Correction: Ultra-small microorganisms in the polyextreme conditions of the Dallol volcano, Northern Afar, Ethiopia.
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SUBMITTER: Gomez F
PROVIDER: S-EPMC7042217 | biostudies-literature | 2020 Feb
REPOSITORIES: biostudies-literature
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Author Correction: Ultra-small microorganisms in the polyextreme conditions of the Dallol volcano, Northern Afar, Ethiopia.
Gómez Felipe F Cavalazzi Barbara B Rodríguez Nuria N Amils Ricardo R Ori Gian Gabriele GG Olsson-Francis Karen K Escudero Cristina C Martínez Jose M JM Miruts Hagos H
Scientific reports 20200226 1
An amendment to this paper has been published and can be accessed via a link at the top of the paper. ...[more]
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Project description:One of the latest volcanic features of the Erta Ale range at the Afar Triangle (NE Ethiopia) has created a polyextreme hydrothermal system located at the Danakil depression on top of a protovolcano known as the dome of Dallol. The interaction of the underlying basaltic magma with the evaporitic salts of the Danakil depression has generated a unique, high-temperature (108 °C), hypersaline (NaCl supersaturated), hyperacidic (pH values from 0.1 to -1.7), oxygen-free hydrothermal site containing up to 150 g/L of iron. We find that the colorful brine pools and mineral patterns of Dallol derive from the slow oxygen diffusion and progressive oxidation of the dissolved ferrous iron, the iron-chlorine/-sulfate complexation, and the evaporation. These inorganic processes induce the precipitation of nanoscale jarosite-group minerals and iron(III)-oxyhydroxides over a vast deposition of halite displaying complex architectures. Our results suggest that life, if present under such conditions, does not play a dominant role in the geochemical cycling and mineral precipitation at Dallol as opposed to other hydrothermal sites. Dallol, a hydrothermal system controlled by iron, is a present-day laboratory for studying the precipitation and progressive oxidation of iron minerals, relevant for geochemical processes occurring at early Earth and Martian environments.
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Project description:A genetic model is proposed for the formation and evolution of volcano-like structures from materials other than molten silicate rocks. The model is based on Mount Dallol (Afar Triangle, Ethiopia), currently hosting a conspicuous hydrothermal system with hot, hyper-acidic springs, forming a colorful landscape of unique mineral patterns. We reason that Mount Dallol is the last stage of the formation of a salt volcano driven by the destabilization of a thick sequence of hydrated minerals (the Houston Formation) after the emplacement of an igneous intrusion beneath the thick Danakil evaporitic sequence. Our claim is supported by field studies, calculations of the mineral/water volume balance upon mineral dehydration, and by a geothermal model of the Danakil basin predicting a temperature up to 220 °C at the Houston Formation after the intrusion of a basaltic magma without direct contact with the evaporitic sequence. Although insufficient for salt melting, this heating triggers mineral dehydration and hydrolysis, leading to a total volume increase of at least 25%. The released brine is segregated upward into a pressurized chamber, where the excess volume produced the doming of Mount Dallol. Later, the collapse of the dome formed a caldera and the emission of clastic flows. The resulting structures and materials resemble volcanic lava flows in distribution, structure, and texture but are entirely made of salty materials. This novel mechanism of the generation of pressurized brines and their later eruption extends the relevance of volcanologic studies to lower temperature ranges and unanticipated geologic contexts on Earth and possibly also on other planets.
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Project description:An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Project description:BackgroundAfrican animal trypanosomosis, transmitted cyclically by tsetse flies or mechanically by other biting flies, causes serious inflictions to livestock health. This study investigates the extent of non-tsetse transmitted animal trypanosomosis (NTTAT) by Trypanosoma (T.) evansi and T. vivax in domestic animals in the tsetse-free regions of Northern Ethiopia, Afar and Tigray.MethodsA cross sectional study was conducted on 754 dromedary camels, 493 cattle, 264 goats, 181 sheep, 84 donkeys, 25 horses and 10 mules. The microhaematocrit centrifugation technique was used as parasitological test. Plasma was collected for serodiagnosis with CATT/T.evansi and RoTat 1.2 immune trypanolysis (ITL) while buffy coat specimens were collected for molecular diagnosis with T. evansi type A specific RoTat 1.2 PCR, T. evansi type B specific EVAB PCR and T. vivax specific TvPRAC PCR.ResultsThe parasitological prevalence was 4.7% in Tigray and 2.7% in Afar and significantly higher (z = 2.53, p = 0.011) in cattle (7.3%) than in the other hosts. Seroprevalence in CATT/T.evansi was 24.6% in Tigray and 13.9% in Afar and was significantly higher (z = 9.39, p < 0.001) in cattle (37.3%) than in the other hosts. On the other hand, seroprevalence assessed by ITL was only 1.9% suggesting cross reaction of CATT/T.evansi with T. vivax or other trypanosome infections. Molecular prevalence of T. evansi type A was 8.0% in Tigray and in Afar and varied from 28.0% in horses to 2.2% in sheep. It was also significantly higher (p < 0.001) in camel (11.7%) than in cattle (6.1%), donkey (6%), goat (3.8%), and sheep (2.2%). Four camels were positive for T. evansi type B. Molecular prevalence of T. vivax was 3.0% and was similar in Tigray and Afar. It didn't differ significantly among the host species except that it was not detected in horses and mules.ConclusionsNTTAT caused by T. vivax and T. evansi, is an important threat to animal health in Tigray and Afar. For the first time, we confirm the presence of T. evansi type B in Ethiopian camels. Unexplained results obtained with the current diagnostic tests in bovines warrant particular efforts to isolate and characterise trypanosome strains that circulate in Northern Ethiopia.
| S-EPMC4403896 | biostudies-literature
Project description:BackgroundUse of modern contraceptive methods reduces the risk of unwanted pregnancy, and is influenced by individual-level factors. Willingness to use modern contraceptive methods maybe a useful metric when considering health outcomes as it could predict health behaviors. Therefore, the current study aimed to assess the willingness of women to use modern contraceptives in Afar pastoralist communities.MethodsA community-based cross-sectional study was conducted from May 1 to 30, 2016. Three hundred forty-five women of childbearing age (15-49 years) were systematically sampled with proportionate allocation from seven randomly selected kebeles (neighborhoods) in Aballa District of Afar Region, Ethiopia. All women meeting the inclusion criteria in each selected household were interviewed at home using a semi-structured questionnaire. Construct validity was assured using factor analysis. A combination of individual behavioral models were applied in order to measure willingness to use modern contraceptive methods. Multiple logistic regressions were utilized to identify factors associated with willingness to use contraceptive at P-value of less than 0.05.ResultsThree hundred twenty-two women participated in the study, for a response rate of 93.3%. The mean age of respondents was 27 (±6) years. About one-third (N = 106, 32.9%) of the participants reported that they were willing to use modern contraceptives. Orthodox Christians (AOR = 4.22, 95% CI 1.94-8.92), women aged 19 or older at first marriage (AOR = 2.89, 95% CI 1.16-7.23), and women who had never experienced a stillbirth (AOR = 3.85, 95%CI 1.37-10.78) were more likely to report being willing to use modern contraceptives. Additionally, perceived severity of an unwanted pregnancy (AOR = 1.71, 95% CI 1.57-1.93) and perceived self-efficacy to use contraceptives (AOR = 1.26, 95% CI 1.17-1.65) were positively associated with the willingness. Women who had never had an abortion were less likely to express willingness to use modern contraceptives (AOR = 0.41, 95% CI 0.19-0.92) and perceived importance of cultural and religious norms (AOR = 0.85, 95% CI 0.62-0.90) was also negatively associated with willingness.ConclusionsThe majority of women in this study were not willing to use modern contraceptive methods. A previous pregnancy outcome of stillbirth was associated with reduced willingness, while a prior abortion was associated with increased willingness. Perceived severity of unwanted pregnancy and higher self-efficacy surrounding contraceptive use were strong predictors of increased willingness to use contraceptives. Religious and cultural norms also appear to influence perception towards modern contraception. Thus, involvement of cultural and religious leaders and consideration of a woman's reproductive history are recommended when designing health education messages on contraception for Afar pastoralist women.
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Project description:Determining the precise limits of life in polyextreme environments is challenging. Studies along gradients of polyextreme conditions in the Dallol proto-volcano area (Danakil salt desert, Ethiopia) showed the occurrence of archaea-dominated communities (up to 99%) in several hypersaline systems but strongly suggested that life did not thrive in the hyperacidic (pH ∼0), hypersaline (∼35% [wt/vol],) and sometimes hot (up to 108°C) ponds of the Dallol dome. However, it was recently claimed that archaea flourish in these brines based on the detection of one Nanohaloarchaeotas 16S rRNA gene and fluorescent in situ hybridization (FISH) experiments with archaea-specific probes. Here, we characterized the diversity of microorganisms in aerosols over Dallol, and we show that, in addition to typical bacteria from soil/dust, they transport halophilic archaea likely originating from neighboring hypersaline ecosystems. We also show that cells and DNA from cultures and natural local halophilic communities are rapidly destroyed upon contact with Dallol brine. Furthermore, we confirm the widespread occurrence of mineral particles, including silica-based biomorphs, in Dallol brines. FISH experiments using appropriate controls show that DNA fluorescent probes and dyes unspecifically bind to mineral precipitates in Dallol brines; cellular morphologies were unambiguously observed only in nearby hypersaline ecosystems. Our results show that airborne cell dispersal and unspecific binding of fluorescent probes are confounding factors likely affecting previous inferences of archaea thriving in Dallol. They highlight the need for controls and the consideration of alternative abiotic explanations before safely drawing conclusions about the presence of life in polyextreme terrestrial or extraterrestrial systems. IMPORTANCE Determining the precise limits of life in polyextreme environments is challenging. Confounding factors such as exogenous contamination and the abiotic formation of structures resembling cells need to be considered before concluding on the unambiguous development of microbial life in low-biomass environments. Here, we explored how these factors can affect contrasting reports about microbial life thriving in the hypersaline and hyperacidic brines of the Dallol geothermal field (Danakil Depression, Ethiopia). We show not only that aerosols actively transport a wide diversity of prokaryotic and eukaryotic cells over Dallol but also that, upon contact with the chaotropic hyperacidic brine, cells and DNA are rapidly degraded. We also show the extant occurrence of mineral (mostly silica-based) biomorphs that unspecifically bind fluorescent probes and dyes. Our study highlights the need for controls and the consideration of alternative abiotic explanations before safely drawing conclusions on the presence of life in polyextreme terrestrial or extraterrestrial systems.
| S-EPMC9040726 | biostudies-literature
Project description:BackgroundTo effectively address the burden of postpartum depression (PPD), it is crucial to gain a comprehensive understanding of its magnitude and the factors associated with it in the pastoral and hot region of the Afar Region. This will help identify the progress made thus far and highlight areas that require further attention to accelerate efforts toward reducing the impact of PPD. Notably, no previous study has examined the prevalence and associated factors of PPD specifically in pastoral communities within Ethiopia, including the Afar Region. Accordingly, we investigated the prevalence and associated factors of PPD among postpartum women in the Afar Region, Northeast Ethiopia.MethodsAn institution-based cross-sectional study was conducted in the Awsi Rasu Zone of Afar Regional State from June to July 2021. The study employed a systematic random sampling method to select a total of 302 postpartum mothers who had visited the Expanded Program of Immunisation (EPI) clinics in public health facilities within the Awsi Rasu Zone of the Afar Region. The measurement of PPD was performed using the Edinburgh Postnatal Depression Scale (EPDS). Multivariable binary logistic regression modelling was used to investigate associations between sociodemographic, obstetric and health service, and psychosocial factors with PPD.ResultsThe overall prevalence of PPD was 37.4% with a 95% confidence interval (CI) from 32.0% to 43.0%. Postpartum women who attained high school education were associated with a lower odds of PPD compared to those who did not attain formal schooling (adjusted odds ratio [AOR] = 0.31; 95% CI: 0.12, 0.82). Postpartum women with a family history of mental illness (AOR = 2.34; 95% CI: 1.24, 4.41), those who had trouble in infant feeding (AOR = 4.26; 95% CI: 2.32, 7.83), and those who experienced intimate partner violence (AOR = 3.09; 95% CI: 1.58, 6.04) were positively associated with PPD.ConclusionThe results of our study revealed that the prevalence of PPD in the Awsi Rasu Zone of the Afar Region is higher than both the national and global averages. The findings also highlighted the need for targeted interventions addressing the needs of pastoral postpartum women who experience various stressors, such as feeding difficulties and intimate partner violence.
| S-EPMC10559328 | biostudies-literature