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1.
Sci Rep ; 14(1): 11071, 2024 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-38745036

RESUMO

The southern coast of Africa is one of the few places in the world where water temperatures are predicted to cool in the future. This endemism-rich coastline is home to two sister species of kelps of the genus Ecklonia maxima and Ecklonia radiata, each associated with specific thermal niches, and occuring primarily on opposite sides of the southern tip of Africa. Historical distribution records indicate that E. maxima has recently shifted its distribution ~ 70 km eastward, to sites where only E. radiata was previously reported. The contact of sister species with contrasting thermal affinities and the occurrence of mixed morphologies raised the hypothesis that hybridization might be occurring in this contact zone. Here we describe the genetic structure of the genus Ecklonia along the southern coast of Africa and investigate potential hybridization and cryptic diversity using a combination of nuclear microsatellites and mitochondrial markers. We found that both species have geographically discrete genetic clusters, consistent with expected phylogeographic breaks along this coastline. In addition, depth-isolated populations were found to harbor unique genetic diversity, including a third Ecklonia lineage. Mito-nuclear discordance and high genetic divergence in the contact zones suggest multiple hybridization events between Ecklonia species. Discordance between morphological and molecular identification suggests the potential influence of abiotic factors leading to convergent phenotypes in the contact zones. Our results highlight an example of cryptic diversity and hybridization driven by contact between two closely related keystone species with contrasting thermal affinities.


Assuntos
Variação Genética , Kelp , Filogenia , Kelp/genética , Kelp/classificação , Filogeografia , Repetições de Microssatélites/genética , Hibridização Genética , DNA Mitocondrial/genética , África Austral
2.
Nat Commun ; 15(1): 2921, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38609362

RESUMO

The blue wildebeest (Connochaetes taurinus) is a keystone species in savanna ecosystems from southern to eastern Africa, and is well known for its spectacular migrations and locally extreme abundance. In contrast, the black wildebeest (C. gnou) is endemic to southern Africa, barely escaped extinction in the 1900s and is feared to be in danger of genetic swamping from the blue wildebeest. Despite the ecological importance of the wildebeest, there is a lack of understanding of how its unique migratory ecology has affected its gene flow, genetic structure and phylogeography. Here, we analyze whole genomes from 121 blue and 22 black wildebeest across the genus' range. We find discrete genetic structure consistent with the morphologically defined subspecies. Unexpectedly, our analyses reveal no signs of recent interspecific admixture, but rather a late Pleistocene introgression of black wildebeest into the southern blue wildebeest populations. Finally, we find that migratory blue wildebeest populations exhibit a combination of long-range panmixia, higher genetic diversity and lower inbreeding levels compared to neighboring populations whose migration has recently been disrupted. These findings provide crucial insights into the evolutionary history of the wildebeest, and tangible genetic evidence for the negative effects of anthropogenic activities on highly migratory ungulates.


Assuntos
Antílopes , Animais , Antílopes/genética , Ecossistema , África Oriental , África Austral , Efeitos Antropogênicos
3.
Nutrients ; 16(7)2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38613007

RESUMO

Selenium is an essential trace element that exists in inorganic forms (selenite and selenates) and organic forms (selenoamino acids, seleno peptides, and selenoproteins). Selenium is known to aid in the function of the immune system for populations where human immunodeficiency virus (HIV) is endemic, as studies suggest that a lack of selenium is associated with a higher risk of mortality among those with HIV. In a recent study conducted in Zambia, adults had a median plasma selenium concentration of 0.27 µmol/L (IQR 0.14-0.43). Concentrations consistent with deficiency (<0.63 µmol/L) were found in 83% of adults. With these results, it can be clearly seen that selenium levels in Southern Africa should be investigated to ensure the good health of both livestock and humans. The recommended selenium dietary requirement of most domesticated livestock is 0.3 mg Se/kg, and in humans above 19 years, anRDA (recommended daily allowance) of 55 mcg Se/per dayisis recommended, but most of the research findings of Southern African countries have recorded low levels. With research findings showing alarming low levels of selenium in soils, humans, and raw feed materials in Southern Africa, further research will be vital in answering questions on how best to improve the selenium status of Southern African soils and plants for livestock and humans to attain sufficient quantities.


Assuntos
Infecções por HIV , Selênio , Adulto , Humanos , Animais , África Austral , Zâmbia , Gado , Solo
4.
Sci Rep ; 14(1): 9151, 2024 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-38644368

RESUMO

Limited commercial quality protein maize (QPM) varieties with low grain yield potential are currently grown in Eastern and Southern Africa (ESA). This study was conducted to (i) assess the performance of single-cross QPM hybrids that were developed from elite inbred lines using line-by-tester mating design and (ii) estimate the general (GCA) and specific (SCA) combining ability of the QPM inbred lines for grain yield, agronomic and protein quality traits. One hundred and six testcrosses and four checks were evaluated across six environments in ESA during 2015 and 2016. Significant variations (P ≤ 0.01) were observed among environments, genotypes and genotype by environment interaction (GEI) for most traits evaluated. Hybrids H80 and H104 were the highest-yielding, most desirable, and stable QPM hybrids. Combining ability analysis showed both additive and non-additive gene effects to be important in the inheritance of grain yield. Additive effects were more important for agronomic and protein quality traits. Inbred lines L19 and L20 depicted desirable GCA effects for grain yield. Various other inbred lines with favorable GCA effects for agronomic traits, endosperm modification, and protein quality traits were identified. These inbred lines could be utilized for breeding desirable QPM cultivars. The QPM hybrids identified in this study could be commercialized after on-farm verification to replace the low-yielding QPM hybrids grown in ESA.


Assuntos
Melhoramento Vegetal , Zea mays , Zea mays/genética , Zea mays/metabolismo , Zea mays/crescimento & desenvolvimento , Melhoramento Vegetal/métodos , África Austral , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , África Oriental , Genótipo , Cruzamentos Genéticos , Endogamia , Fenótipo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
5.
PLoS One ; 19(4): e0301850, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38669230

RESUMO

BACKGROUND: Spatial analysis at different levels can help understand spatial variation of human immunodeficiency virus (HIV) infection, disease drivers, and targeted interventions. Combining spatial analysis and the evaluation of the determinants of the HIV burden in Southern African countries is essential for a better understanding of the disease dynamics in high-burden settings. METHODS: The study countries were selected based on the availability of demographic and health surveys (DHS) and corresponding geographic coordinates. We used multivariable regression to evaluate the determinants of HIV burden and assessed the presence and nature of HIV spatial autocorrelation in six Southern African countries. RESULTS: The overall prevalence of HIV for each country varied between 11.3% in Zambia and 22.4% in South Africa. The HIV prevalence rate was higher among female respondents in all six countries. There were reductions in prevalence estimates in most countries yearly from 2011 to 2020. The hotspot cluster findings show that the major cities in each country are the key sites of high HIV burden. Compared with female respondents, the odds of being HIV positive were lesser among the male respondents. The probability of HIV infection was higher among those who had sexually transmitted infections (STI) in the last 12 months, divorced and widowed individuals, and women aged 25 years and older. CONCLUSIONS: Our research findings show that analysis of survey data could provide reasonable estimates of the wide-ranging spatial structure of the HIV epidemic in Southern African countries. Key determinants such as individuals who are divorced, middle-aged women, and people who recently treated STIs, should be the focus of HIV prevention and control interventions. The spatial distribution of high-burden areas for HIV in the selected countries was more pronounced in the major cities. Interventions should also be focused on locations identified as hotspot clusters.


Assuntos
Infecções por HIV , Humanos , Feminino , Infecções por HIV/epidemiologia , Masculino , Adulto , Prevalência , Adolescente , Adulto Jovem , Pessoa de Meia-Idade , África do Sul/epidemiologia , Análise Espacial , Zâmbia/epidemiologia , Inquéritos Epidemiológicos , África Austral/epidemiologia
6.
BMJ Glob Health ; 9(4)2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38594203

RESUMO

In 2019, there were 21 million pregnancies among adolescents aged 15-19 years globally; close to half of these pregnancies were unintended. Early and unintended pregnancy (EUP) remains a pressing concern with severe socioeconomic and health outcomes for adolescent girls aged 15-19 years, their offspring and society. In Eastern and Southern Africa (ESA), Zambia, the United Republic of Tanzania, the Democratic Republic of Congo, Malawi and Uganda have adolescent fertility rates (AFR) of more than 100 live births per 1000 adolescent girls aged 15-19 years. Ministers of Health and Education, through the ESA Ministerial Commitment, aimed to reduce EUP by 75% by 2020; the renewed ESA Ministerial Commitment aims to reduce EUP by 40% by 2030. This descriptive policy content analysis assesses the prioritisation of EUP within adolescent sexual and reproductive health and rights (ASRHR) policies. An assessment of nine countries in the region shows that EUP is a key policy priority among countries; however, other than Kenya, the majority of ASRHR policies in the region do not set out clear and costed interventions for EUP, and few have monitoring and evaluation frameworks in place. Despite AFRs declining in Kenya and strong policies in place, the gains made are at risk due to the rollback on SRHR, and the country has not renewed the ESA Ministerial Commitment. This policy content analysis points towards the gaps we are still to meet within the universal health coverage agenda: better planning, prioritisation, sound policy frameworks and long-term commitments to meet the needs of adolescents.


Assuntos
Gravidez não Planejada , Saúde Reprodutiva , Gravidez , Feminino , Adolescente , Humanos , África Austral/epidemiologia , Tanzânia , Políticas
7.
Syst Parasitol ; 101(3): 32, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38647716

RESUMO

Seven species belonging to Pennellidae are reported from marine teleosts caught off southern Africa. Additionally, complete re-descriptions are provided for Propeniculus stromatei and Sarcotretes scopeli. Examination of Lernaeenicus gonostomae, deposited in the Iziko South African Museum, indicated that it has the morphological features of Sarcotretes rather than Lernaeenicus and thus should be moved to Sarcotretes i.e. S. gonostomae n. comb. for which a re-description is also provided. Reports of new host records include those of Pennella instructa from Seriola lalandi; Propeniculus stromatei from Rhabdosargus holubi and Pomadasys commersonnii; Sarcotretes scopeli from Nansenia tenera, and Sarcotretes longirostris from Centrolophus niger. New geographical records include those of P. instructa, P. stromatei, S. scopeli, S. longirostris, and L. longiventris off southern Africa. Additionally, an attempt to estimate the evolutionary relationships amongst some genera is done from partial COI sequences deposited in Genbank.


Assuntos
Copépodes , Especificidade da Espécie , Animais , Copépodes/classificação , Copépodes/anatomia & histologia , Feminino , África Austral , África do Sul , Peixes/parasitologia
8.
Food Res Int ; 184: 114200, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38609207

RESUMO

Various species of Southern African plants and their edible seeds have gained huge importance due to positive health aspects, and there is increasing interest to introduce such seeds as Novel Food on the international market. Especially the seeds of Schinziophyton rautanenii (manketti) and Guibourtia coleosperma (ushivi) could have great potential as a food and food ingredient. Hence, extensive analyses on the chemical composition of manketti nuts and ushivi beans including the analysis of total solids, protein and fat content, soluble carbohydrates, ash, total and free amino acids, biogenic amines and polyamines, fatty acid profile as well as the content of certain B-vitamins and tocopherols were performed. Results obtained showed a valuable nutritional composition, e.g., a true protein content of 22.6% with a ratio of essential amino acids to total amino acid composition of 48% in manketti nuts, while ushivi beans had a true protein content of 8.2% with a similar ratio of essential to total amino acids (45%). Lipid content was 54.1% in manketti nuts, ushivi beans had a value of 7.7%. In both, linoleic acid was the most abundant. Furthermore, ushivi beans had high amounts of vitamin B1 and B2.


Assuntos
Euphorbiaceae , Fabaceae , Nozes , Sementes , África Austral , Aminoácidos
9.
Pan Afr Med J ; 47: 31, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38586072

RESUMO

Introduction: the Africa region was certified indigenous wild poliovirus-free in August 2020. Countries in East and Southern Africa have, during acute flaccid paralysis (AFP) and environmental surveillance (ES), detected equally concerning vaccine-derived polioviruses (VDPVs) that have not been systematically documented to guide programming in the sub-region. The study documents trends and salient observations of the VDPVs by country of detection, for 11 years from 2010 to 2021. Methods: we conducted secondary data analysis, a descriptive study design, by deploying field and laboratory of AFP and environmental surveillance databases of the 20 East and Southern African countries from 2010 to 2021. Results: a total of 318 VDPVs were reported over the study period. The majority were from AFP cases (58.8%) and the rest equally distributed between healthy community children and environmental surveillance sources. More polioviruses were detected after 2016 than during the period before. We observed that more boys were affected by VDPVs compared to girls. Children under 5 years were more affected than other age groups, with a mean age of 3.6 years. Delay of samples in the field seemed to increase the likelihood of not reporting VDPVs and not mounting timely public health detailed investigations and vaccination responses. Conclusion: the study provides useful evolutional trends of VDPVs for surveillance and vaccination programming. We also noted that the VDPV2s have been increasing after the 2016 tOPV to oral polio vaccine (bOPV) switch. The COVID-19 pandemic emergence in 2020, led to a decline in AFP, ES surveillance, and immunization activities. Our findings point to the need to implement enhanced tailored childhood immunization recovery strategies and to speed up the use of inactivated polio vaccine (IPV) to boost population immunity.


Assuntos
Poliomielite , Poliovirus , Criança , Masculino , Feminino , Humanos , Pré-Escolar , Poliomielite/epidemiologia , Poliomielite/prevenção & controle , Pandemias , alfa-Fetoproteínas , Vacina Antipólio Oral , Vacina Antipólio de Vírus Inativado , África Austral/epidemiologia
10.
Trop Anim Health Prod ; 56(2): 100, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38472670

RESUMO

Gastrointestinal nematodes (GIN) exacerbate the impact of droughts on the survival of cattle. The inadequacies of the conventional system make it increasingly important to explore indigenous knowledge (IK) to create drought-tolerant and GIN resilient herds. The objective of the study was to assess the indigenous strategies for controlling GIN during droughts. Face-to-face interviews with experts on IK were conducted to give insight into the importance, methods and ranking of GIN control. The experts identified 86 cattle that were used to test their assertions. The control methods used were identifying cattle that were susceptible to high GIN loads using predisposing factors, diagnosis of GIN burdens using faecal appearance, and treatment using phytotherapy. Experts ranked predisposing factors as the most critical control strategy and identified body condition, class, sex, coat colour, pregnancy status and lactation status as predisposing factors to high GIN burdens. Thin, older, dark-coloured cattle, as well as pregnant and lactating cows, were considered susceptible to GIN. However, pregnancy status, coat colour and sex were significantly associated with high GIN burdens. Cows were 2.6 times more likely to have high GIN burdens than bulls. Dark-coloured cattle were 3.5 times more likely to have high GIN burdens than light-coloured ones, and the likelihood of pregnant cows was 4.9 times higher than non-pregnant cows. A dark-coloured pregnant cow was extremely susceptible to high GIN burdens. In conclusion, knowledge of predisposing factors informs selection decisions when purchasing foundation stock. Cattle that are susceptible to high GIN loads are prioritised during droughts or culled where resources are scarce.


Assuntos
Doenças dos Bovinos , Nematoides , Feminino , Animais , Bovinos , Masculino , Gravidez , Lactação , Trato Gastrointestinal , África Austral
11.
PLoS One ; 19(3): e0298387, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38478528

RESUMO

BACKGROUND: Male circumcision (MC) is a key part of the package of interventions to prevent HIV, the biggest health challenge in sub-Saharan Africa. OBJECTIVE: To estimate the male circumcision prevalence and to evaluate the progress towards meeting WHO targets in sub-Saharan Africa during the period 2010-2023. METHODS: We carried out a systematic review and meta-analysis of studies published during the period 2010-2023. We searched PubMed, Scopus, Cochrane CENTRAL, Google Scholar, WHO and the Demographic and Health Survey for reports on MC prevalence in sub-Saharan Africa. MC prevalence was synthesized using inverse-variance heterogeneity models, heterogeneity using I2 statistics and publication bias using funnel plots. RESULTS: A total of 53 studies were included. The overall prevalence during the study period was 45.9% (95% CI 32.3-59.8), with a higher MC prevalence in Eastern (69.9%, 95%CI 49.9-86.8) compared to Southern African (33.3%, 95%CI 21.7-46.2). The overall prevalence was higher in urban (45.3%, 95%CI 27.7-63.4) compared to rural settings (42.6%, 95% 26.5-59.5). Male circumcision prevalence increased from 40.2% (95% CI 25.0-56.3) during 2010-2015 to 56.2% (95% CI 31.5-79.5) during 2016-2023. Three countries exceeded 80% MC coverage, namely, Ethiopia, Kenya and Tanzania. CONCLUSION: Overall, the current MC prevalence is below 50%, with higher prevalence in Eastern African countries and substantially lower prevalence in Southern Africa. Most of the priority countries need to do more to scale up medical male circumcision programs.


Assuntos
Circuncisão Masculina , Infecções por HIV , Masculino , Humanos , Feminino , Prevalência , África Austral/epidemiologia , Etiópia , Quênia , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle
12.
Zootaxa ; 5399(5): 451-504, 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38480124

RESUMO

As part of a revision of the Afrotropical species of Trachelas L. Koch, 1872 (Araneae: Trachelidae), we distinguished three new genera of primarily arboreal spiders from southern Africa that are described here: Coronarachne gen. nov., represented by four new species known from both sexes, C. denticulata sp. nov. (type species), C. penicillus sp. nov., C. setosa sp. nov. and C. unigena sp. nov., and C. neethlingi sp. nov., known only from the male; Falcaranea gen. nov., represented by three new species known from both sexes, F. amatola sp. nov., F. gladius sp. nov. (type species) and F. maputensis sp. nov.; and Trachecymbius gen. nov., represented by five new species, T. bosselaersi sp. nov. (), T. felis sp. nov. (), T. peterwebbi sp. nov. (), T. tyume sp. nov. (type species, ), and T. umbella sp. nov. (). These three genera share the presence of strongly protruding setal bases on the ventral surfaces of the anterior legs, which are more strongly developed in males and can be mistaken for small ventral cusps that are found in several trachelid genera. Identification keys are provided for each of the three genera and their phylogenetic affinities to other Afrotropical Trachelidae are evaluated based on the cytochrome oxidase c subunit I (COI) gene. Most of the species described here were common in canopy fogging samples, and to a lesser extent beating, but are clearly a prominent component of the arboreal trachelid fauna in savanna and forest habitats in southern Africa.


Assuntos
Aranhas , Feminino , Masculino , Animais , Filogenia , África Austral , Ecossistema , Florestas , Distribuição Animal
13.
Zootaxa ; 5419(1): 85-111, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38480336

RESUMO

Siphonostomatoida (Copepoda) consists of 40 families of symbionts infecting vertebrates (17 families) and invertebrates (23 families) found mostly in marine habitats. In 2004, a list was compiled of all the reported families, genera and species symbiotic with marine fish in Southern African waters. Since this was done 20 years ago, it is necessary to re-evaluate the progress made in 20 years regarding our knowledge of the diversity of marine siphonostomatoids. To assess the current knowledge, the 2004 list was updated with reports published since 2004 as well as with new host and locality records including species with changes in taxonomy. Additionally, species collected but unreported as well as species previously reported but with new hosts and/or localities were also added. Currently reports include 16 families, 75 genera and 234 species. However, amongst these are reports of only two families (3 species) infecting invertebrates. Even though the report includes 71 additional species it still compares poorly with the about 2 274 accepted species, especially regarding species infecting invertebrates. Considering South Africas wealth in possible marine host species, examination of more hosts (especially marine teleosts and invertebrates) will definitely result in an increase in the current knowledge about the biodiversity of marine siphonostomatoids off Southern Africa.


Assuntos
Copépodes , Animais , Biodiversidade , Invertebrados , África Austral , Vertebrados
14.
Yeast ; 41(5): 330-348, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38450792

RESUMO

Yeast-insect interactions are one of the most interesting long-standing relationships whose research has contributed to our understanding of yeast biodiversity and their industrial applications. Although insect-derived yeast strains are exploited for industrial fermentations, only a limited number of such applications has been documented. The search for novel yeasts from insects is attractive to augment the currently domesticated and commercialized production strains. More specifically, there is potential in tapping the insects native to southern Africa. Southern Africa is home to a disproportionately high fraction of global biodiversity with a cluster of biomes and a broad climate range. This review presents arguments on the roles of the mutualistic relationship between yeasts and insects, the presence of diverse pristine environments and a long history of spontaneous food and beverage fermentations as the potential source of novelty. The review further discusses the recent advances in novelty of industrial strains of insect origin, as well as various ancient and modern-day industries that could be improved by use yeasts from insect origin. The major focus of the review is on the relationship between insects and yeasts in southern African ecosystems as a potential source of novel industrial yeast strains for modern bioprocesses.


Assuntos
Biodiversidade , Insetos , Leveduras , Insetos/microbiologia , Animais , Leveduras/classificação , Leveduras/fisiologia , Leveduras/genética , África Austral , Fermentação , Simbiose , Microbiologia Industrial
15.
Nature ; 629(8010): 114-120, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38538797

RESUMO

Mountain ranges contain high concentrations of endemic species and are indispensable refugia for lowland species that are facing anthropogenic climate change1,2. Forecasting biodiversity redistribution hinges on assessing whether species can track shifting isotherms as the climate warms3,4. However, a global analysis of the velocities of isotherm shifts along elevation gradients is hindered by the scarcity of weather stations in mountainous regions5. Here we address this issue by mapping the lapse rate of temperature (LRT) across mountain regions globally, both by using satellite data (SLRT) and by using the laws of thermodynamics to account for water vapour6 (that is, the moist adiabatic lapse rate (MALRT)). By dividing the rate of surface warming from 1971 to 2020 by either the SLRT or the MALRT, we provide maps of vertical isotherm shift velocities. We identify 17 mountain regions with exceptionally high vertical isotherm shift velocities (greater than 11.67 m per year for the SLRT; greater than 8.25 m per year for the MALRT), predominantly in dry areas but also in wet regions with shallow lapse rates; for example, northern Sumatra, the Brazilian highlands and southern Africa. By linking these velocities to the velocities of species range shifts, we report instances of close tracking in mountains with lower climate velocities. However, many species lag behind, suggesting that range shift dynamics would persist even if we managed to curb climate-change trajectories. Our findings are key for devising global conservation strategies, particularly in the 17 high-velocity mountain regions that we have identified.


Assuntos
Altitude , Migração Animal , Biodiversidade , Mapeamento Geográfico , Aquecimento Global , Animais , África Austral , Brasil , Conservação dos Recursos Naturais , Aquecimento Global/estatística & dados numéricos , Umidade , Indonésia , Chuva , Refúgio de Vida Selvagem , Imagens de Satélites , Especificidade da Espécie , Temperatura , Fatores de Tempo
16.
Mol Ecol Resour ; 24(4): e13942, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38390664

RESUMO

Environmental DNA (eDNA) is used for biodiversity assessments in a variety of ecosystems across the globe, whereby different eDNA concentration, preservation and extraction methods can outperform others depending on the sampling conditions and environment. Tropical and subtropical ecosystems in Africa are among the less studied systems concerning eDNA-based monitoring. Waterholes in arid parts of southern Africa represent important agglomeration points for terrestrial mammals, and the eDNA shed into such waterbodies provides a powerful source of information for monitoring mammalian biodiversity in the surrounding area. However, the applied methods for eDNA sampling, preservation and filtering in different freshwater systems vary greatly, and rigorous protocol testing in African freshwater systems is still lacking. This study represents the first attempt to examine variations in eDNA concentration, preservation and extraction methods under remote field conditions using waterborne eDNA in a savanna system. Collected samples were heavily affected by microalgal and bacterial growth, impeding eDNA capture and PCR success. We demonstrate clear effects of the methodological choices, which also depend on the state of eDNA. A preliminary metabarcoding run showed little taxonomic overlap in mammal species detection between two metabarcoding primers tested. We recommend water filtering (using filters with pore sizes >1 µm) over centrifugation for eDNA concentration, Longmire's solution for ambient temperature sample preservation and Qiagen's DNeasy PowerSoil Pro Kit for DNA extraction of these inhibitor-prone samples. Furthermore, at least two independent metabarcoding markers should be utilized in order to maximize species detections in metabarcoding studies.


Assuntos
DNA Ambiental , Animais , DNA Ambiental/genética , Ecossistema , DNA/genética , Pradaria , Biodiversidade , Mamíferos/genética , África Austral , Monitoramento Ambiental/métodos , Código de Barras de DNA Taxonômico/métodos
17.
Proc Natl Acad Sci U S A ; 121(10): e2318560121, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38408239

RESUMO

In the Stone Age, the collection of specific rocks was the first step in tool making. Very little is known about the choices made during tool-stone acquisition. Were choices governed by the knowledge of, and need for, specific properties of stones? Or were the collected raw materials a mere by-product of the way people moved through the landscape? We investigate these questions in the Middle Stone Age (MSA) of southern Africa, analyzing the mechanical properties of tool-stones used at the site Diepkloof Rock Shelter. To understand knapping quality, we measure flaking predictability and introduce a physical model that allows calculating the relative force necessary to produce flakes from different rocks. To evaluate their quality as finished tools, we investigate their resistance during repeated use activities (scraping or cutting) and their strength during projectile impacts. Our findings explain tool-stone selection in two emblematic periods of the MSA, the Still Bay and Howiesons Poort, as being the result of a deep understanding of these mechanical properties. In both cases, people chose those rocks, among many others, that allowed the most advantageous trade-off between anticipated properties of finished tools and the ease of acquiring rocks and producing tools. The implications are an understanding of African MSA toolmakers as engineers who carefully weighed their choices taking into account workability and the quality of the tools they made.


Assuntos
Arqueologia , Tecnologia , Humanos , África Austral
18.
Malar J ; 23(1): 62, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38419105

RESUMO

BACKGROUND: Malaria elimination requires closely co-ordinated action between neighbouring countries. In Southern Africa several countries have reduced malaria to low levels, but the goal of elimination has eluded them thus far. The Southern Africa Development Community (SADC) Malaria Elimination Eight (E8) initiative was established in 2009 between Angola, Botswana, Eswatini, Mozambique, Namibia, South Africa, Zambia, and Zimbabwe to coordinate malaria interventions aiming to eliminate malaria by 2030. Cross-border coordination is important in malaria elimination settings as it strengthens surveillance, joint planning and implementation, knowledge exchange and optimal use of resources. This paper describes how this collaboration is realized in practice, its achievements and challenges, and its significance for malaria elimination prospects. METHODS: The ministers of health of the E8 countries oversee an intergovernmental technical committee supported by specialist working groups consisting of technical personnel from member countries and partner institutions. These technical working groups are responsible for malaria elimination initiatives in key focus areas such as surveillance, vector control, diagnosis, case management, behaviour change and applied research. The technical working groups have initiated and guided several collaborative projects which lay essential groundwork for malaria elimination. RESULTS: The E8 collaboration has yielded achievements in the following key areas. (1) Establishment and evaluation of malaria border health posts to improve malaria services in border areas and reduce malaria among resident and, mobile and migrant populations. (2) The development of a regional malaria microscopy slide bank providing materials for diagnostic training and proficiency testing. (3) A facility for regional external competency assessment and training of malaria microscopy trainers in collaboration with the World Health Organization. (4) Entomology fellowships that improved capacity in entomological surveillance; an indoor residual spraying (IRS) training of trainers' scheme to enhance the quality of this core intervention in the region. (5) Capacity development for regional malaria parasite genomic surveillance. (6) A mechanism for early detection of malaria outbreak through near real time reporting and a quarterly bulletins of malaria incidence in border districts. CONCLUSIONS: The E8 technical working groups system embodies inter-country collaboration of malaria control and elimination activities. It facilitates sustained interaction between countries through a regional approach. The groundwork for elimination has been laid, but the challenge will be to maintain funding for collaboration at this level whilst reducing reliance on international donors and to build capacities necessary to prepare for malaria elimination.


Assuntos
Malária , Humanos , Malária/epidemiologia , Malária/prevenção & controle , África Austral/epidemiologia , Surtos de Doenças , Moçambique/epidemiologia , África do Sul/epidemiologia
19.
AIDS ; 38(3): 273-287, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38300157

RESUMO

In sub-Saharan Africa (SSA), MSM - a high HIV prevalence group - experience strong social stigma and pressure to have female partners. Accordingly, they could constitute a bridging group for HIV transmission to cisgender women. We developed a multilevel summary of MSM sexual behaviors and risk with women in various SSA regions. Following PRISMA guidelines, we conducted a mixed-method systematic review of data of sex with women in MSM in SSA. We performed meta-analyses on quantitative data (i.e. percent of recent sex and condomless sex with women) for each SSA region (when proportions reported in ≥4 studies). Pooled proportions were calculated using random-effects models. Qualitative data were analyzed using the three-step thematic synthesis methodology. The pooled proportion of MSM who had sex with women was 58% (33-83%) in East Africa (in the previous 3 months), and 27% (13-48%) in Southern Africa and 50% (95% CI 39-62%) in West Africa (in the previous 6 months); 23% (16-32%) of MSM in West Africa had condomless sex with a woman (during the most recent encounter). Approximately one quarter of MSM had recent multiple female partners. MSM reported having sex with women because of heteronormative pressure, erotic/romantic attraction, or financial needs leading to transactional sex. MSM may act as a bridging population to women in SSA, as they commonly practice sex with women and risky sexual behaviors with them. HIV programmes and community-based support for MSM should be adapted to this population to reduce this risk.


Assuntos
Infecções por HIV , Feminino , Humanos , Infecções por HIV/epidemiologia , Comportamento Sexual , África Ocidental , África Oriental , África Austral
20.
BMC Public Health ; 24(1): 239, 2024 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-38245689

RESUMO

BACKGROUND: HIV remains a leading cause of death for adolescents and young people aged 10-24 years. HIV prevention requires multisectoral approaches that target adolescents and young people, addressing HIV risk pathways (e.g., transactional sex, gender-based violence, and school attendance) through bundled interventions that combine economic strengthening, health capabilities, and gender equality education. However, best practices are unknown because evidence on multisectoral programming targeted to adolescents and combining these components has not been systematically reviewed. METHODS: We conducted a systematic review to summarize the evidence on bundled interventions combining health and economic strengthening components for adolescents and young people and their effects on HIV/STI incidence and risk factors. We included studies from Africa published between 2005 and 2023, combining at least one economic strengthening and one health component, directed toward adolescents and young people aged 10-24 years. Included studies measured programmatic impacts on primary outcomes: HIV and STI incidence/prevalence; and mediators as secondary outcomes: sexual behaviours, sexual and reproductive health, school attendance, health-seeking behaviours, and violence. We conducted key word searches in PubMed, EMBASE, and Web of Science, imported titles/abstracts from the initial search, and reviewed them using the inclusion criteria. Full texts of selected articles were reviewed and information was extracted for analysis. Findings from the full texts identified were summarized. RESULTS: We reviewed 58 studies, including 43 quantitative studies and 15 qualitative studies, evaluating 26 unique interventions. A majority of studies reviewed were conducted in Eastern and Southern Africa. Interventions reviewed showed a greater number of significant results in improving economic outcomes; mental health and psychosocial outcomes; sexual and reproductive health knowledge and services utilization; and HIV prevention knowledge and testing. They showed fewer significant results in improving outcomes related to HIV incidence/prevalence; sexual risk behaviours; gender-based violence; gender attitudes; education; STI incidence, prevalence and testing; and sexual debut. CONCLUSIONS: Our review demonstrated the potential for bundled, multisectoral interventions for preventing HIV and facilitating safe transitions to adulthood. Findings have implications for designing HIV sensitive programmes on a larger scale, including how interventions may need to address multiple strata of the social ecological model to achieve success in the prevention of HIV and related pathways.


Assuntos
Síndrome da Imunodeficiência Adquirida , Infecções por HIV , Infecções Sexualmente Transmissíveis , Humanos , Adolescente , Infecções Sexualmente Transmissíveis/epidemiologia , Infecções Sexualmente Transmissíveis/prevenção & controle , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Comportamento Sexual/psicologia , África Austral
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