Entomological survey in the historical focus of human African trypanosomiasis of Bendje (Gabon)

The situation of human African trypanosomiasis (sleeping sickness) is poorly known in Gabon. Most of the historical foci have not been investigated for more than 15 years. Few cases are passively recorded from the historical focus of Bendjé; they involved mainly fishermen but determining their contamination site is difficult because of their mobility due to their activity. The presence of these cases in that focus could favour its reactivation if the vector is still there. In order to assess a potential transmission risk in that area, an entomological survey has been carried out in it. Traps were set up during four days in different habitats used by humans during their daily activities. Three species of tsetse flies (Glossina palpalis palpalis, G. pallicera newsteadi and G. caliginea) were caught and two species of trypanosomes (Trypanosoma vivax and T. brucei s.l.) were identified by PCR. These results suggest the presence of an animal transmission cycle. Human-flies contact was confirmed in all type of habitats but no transmission was quantified in the mangrove.     

Ability of the Actiwatch Accelerometer to Predict Free‐Living Energy Expenditure in Young Children

Objective: To determine whether activity counts obtained with the Actiwatch monitor are associated with total expenditure and body composition in young children. Research Methods and Procedures: Actiwatch activity monitors were tested in 29 children 4 to 6 years old under field conditions over eight days. Total energy expenditure (TEE) was assessed with the doubly labeled water (DLW) technique. Correlation analyses were used to identify variables related to energy expenditure and percentage body fat. Multiple linear regression analyses were used to examine the variance in TEE and percentage body fat explained by activity counts after adjusting for relevant covariates. Results: Both average total daily activity counts (658, 816 ± 201, 657) and the pattern of activity were highly variable among subjects. TEE was significantly related to lean body mass (r = 0.45) and age (r = 0.48; p < 0.05 for both). Activity counts alone were not associated with TEE. In multiple linear regression analyses, TEE was independently associated with only lean body mass. Percentage fat mass was independently associated with body weight, being a girl, and being white, but not with average total activity counts. Discussion: Activity counts obtained with the Actiwatch under free‐living conditions do not reflect TEE in 4‐ to 6‐year‐old children and are not correlated with percentage fat mass. Therefore, average total activity counts obtained with the Actiwatch may be of limited value in identifying children at risk for becoming obese.     

Determination of isotope ratios in human tissues enriched with zinc stable isotope tracers using inductively coupled plasma-mass spectrometry (ICP-MS)

Enriched fecal and urine samples were prepared using ion-exchange column chromatography for analysis by Inductively Coupled and Fast Atom Bombardment Mass spectrometry (ICP-MS, FAB-MS) to compare precision between methods. Unenriched samples of human milk, feces, and whole blood were prepared similarly to monitor instrumental precision and analytical error. A least squares fit of the ICP-MS results vs the FAB-MS for⁷⁰Zn/⁶⁴Zn gave a slope of 0.98, with a relative standard deviation (RSD) of only 0.7%. The results for⁶⁸Zn/⁶⁴Zn gave a slope of 0.82, with a RSD of 14%. For unenriched tissues, all potential interferences were removed by the preparation procedure with no significant differences between preparation for isotope ratios of⁷⁰Zn/⁶⁴Zn,⁶⁸Zn/⁶⁴Zn,⁶⁷Zn/⁶⁴Zn, and⁶⁶Zn/⁶⁴Zn. Poisson counting statistics are a major contribution to the total analytical error indicating the usefulness of this procedure for enrichment studies.     

Key factors and related principles in the conservation of large African carnivores

相似文献   

中国与非洲近代-现代人类某些颅骨特征的对比及其意义--中国与非洲人类头骨特征对比之二

对近代—现代非洲和中国人群26项颅骨特征的观测和分析显示非洲人具有一些显示其特异性的颅骨特征,但多数特征的表现与东亚人类非常接近,提示现代人群体质特征的趋同性。作者认为非洲人在多数颅骨特征的表现方式上较中国人更为多样化,表明现代非洲人群在体质特征的表现上较东亚人类具有更宽广的形态变异谱。作者基于许多东亚、欧洲及澳洲人类的颅骨特征在非洲人群具有较高的出现率或明显的表现等现象提出一些未来研究中有待解决的问题。     

Compartmental modeling to quantify alpha-linolenic acid conversion after longer term intake of multiple tracer boluses

To estimate in vivo alpha-linolenic acid (ALA; C18:3n-3) conversion, 29 healthy subjects consumed for 28 days a diet providing 7% of energy from linoleic acid (C18:2n-6) and 0.4% from ALA. On day 19, subjects received a single bolus of 30 mg of uniformly labeled [(13)C]ALA and for the next 8 days 10 mg twice daily. Fasting plasma phospholipid concentrations of (12)C- and (13)C-labeled ALA, eicosapentaenoic acid (EPA; C20:5n-3), docosapentaenoic acid (DPA; C22:5n-3), and docosahexaenoic acid (DHA; C22:6n-3) were determined on days 19, 21, 23, 26, 27, and 28. To estimate hepatic conversion of n-3 fatty acids, a tracer model was developed based on the averaged (13)C data of the participants. A similar tracee model was solved using the averaged (12)C values, the kinetic parameters derived from the tracer model, and mean ALA consumption. ALA incorporation into plasma phospholipids was estimated by solving both models simultaneously. It was found that nearly 7% of dietary ALA was incorporated into plasma phospholipids. From this pool, 99.8% was converted into EPA and 1% was converted into DPA and subsequently into DHA. The limited incorporation of dietary ALA into the hepatic phospholipid pool contributes to the low hepatic conversion of ALA into EPA. A low conversion of ALA-derived EPA into DPA might be an additional obstacle for DHA synthesis.     

A simple carbon isotope model for reconstructing prehistoric human diet

A compilation of experimental animal data shows that neither delta13C(collagen) nor delta13C(apatite) nor Delta13C(CO-AP) indicate diagnostic reconstructions of diet, diet energy and diet protein. In contrast, plots of delta13C(collagen) against delta13C(apatite) provide a model of three regression lines (C3, C4, and marine diet protein) where position on each line indicates the energy source (C3, C4, or mixed). Neither body size nor trophic position appears to affect these relationships. Modern free-ranging, terrestrial fauna do not fit the model perhaps because they, unlike the experimental fauna, mainly use fermentation rather than digestion during energy metabolism. Archaeological humans fall as expected based on associated floral and faunal evidence. Foraging people plot at positions expected from associated C3 fauna and plants. Those from Cahokia plot, as expected, from associated deer, nuts, and maize whereas people from nearby smaller sites plot in positions consistent with eating more fish. Agriculturists from Ontario and Grasshopper Pueblo plot consistent with dependence on fish by the former and on turkeys by the latter. In Tierra del Fuego, people from interior regions ate more terrestrial fauna, as suggested by ethnohistoric reports, than did people from the coast. In the Southwestern Cape in South Africa individuals late in the sequence have pure C3 diets whereas ones early in the sequence ate marine protein as suggested by independent archaeological evidence. People on San Nicolas Island depended on C4 plants in contrast to other islands off California's coast. This simple model provides more detailed and precise dietary information than do individual isotopic measures.     

The interactions between humans and mammals in Africa in relation to conservation: a review

Most human-mammal interactions are detrimental to wild mammals. In Africa, mammalian population numbers and the geographical distribution of many species have been reduced due to hunting, pastoralism, habitat modification and disease control. The importance of each of these factors depends on the species, its location and habitat, and density of the human population. In contrast, some small- and medium-sized species have benefited from human activities, and there has been an increase in the population numbers of some species in well-managed and well-protected conservation areas. There appears to be a strong negative correlation (at least for some well-studied species) between density of humans and density of mammals. Recently, several African countries, notably in southern Africa, have developed the principle of integrated rural development in which local people are involved in the planning and administration of their traditional lands. Managed conservation areas are an integral part of good land-use policies. Surveys indicate that most Africans living close to conservation areas, especially those with a higher level of education, understand and support the ideals of conservation; nevertheless it is important that the benefits of conservation and integrated development (such as money, jobs, and food) directly benefit the local people. Conservation of mammals (and all other species) in Africa in the future will only succeed if there is participation at the grass roots level, better food production in designated agricultural areas, reduction in the rate of increase of human populations, stabilization of human densities, and active programmes of conservation education.     

Contrasting long‐term records of biomass burning in wet and dry savannas of equatorial East Africa

Rainfall controls fire in tropical savanna ecosystems through impacting both the amount and flammability of plant biomass, and consequently, predicted changes in tropical precipitation over the next century are likely to have contrasting effects on the fire regimes of wet and dry savannas. We reconstructed the long‐term dynamics of biomass burning in equatorial East Africa, using fossil charcoal particles from two well‐dated lake‐sediment records in western Uganda and central Kenya. We compared these high‐resolution (5 years/sample) time series of biomass burning, spanning the last 3800 and 1200 years, with independent data on past hydroclimatic variability and vegetation dynamics. In western Uganda, a rapid (<100 years) and permanent increase in burning occurred around 2170 years ago, when climatic drying replaced semideciduous forest by wooded grassland. At the century time scale, biomass burning was inversely related to moisture balance for much of the next two millennia until ca. 1750 ad , when burning increased strongly despite regional climate becoming wetter. A sustained decrease in burning since the mid20th century reflects the intensified modern‐day landscape conversion into cropland and plantations. In contrast, in semiarid central Kenya, biomass burning peaked at intermediate moisture‐balance levels, whereas it was lower both during the wettest and driest multidecadal periods of the last 1200 years. Here, burning steadily increased since the mid20th century, presumably due to more frequent deliberate ignitions for bush clearing and cattle ranching. Both the observed historical trends and regional contrasts in biomass burning are consistent with spatial variability in fire regimes across the African savanna biome today. They demonstrate the strong dependence of East African fire regimes on both climatic moisture balance and vegetation, and the extent to which this dependence is now being overridden by anthropogenic activity.     

Morphologic variability of human African populations south of the Sahara

Morphologic relationships between 133 African populations from south of the Sahara are analysed on the basis of 7 anthropometric variables by means of correspondence analysis.As far as concerns the morphologic characteristic, the distribution of populations on the plane formed by the first two factorial axes, which account for 85% of the total variability of data, (1) shows a certain geographic pattern, (2) is continuous, without forming any particular easily circumscribed groupings, and (3) indicates an association with the habitat in which the populations live.     

Proteomics: a new way to improve human African trypanosomiasis diagnosis?

African trypanosomiases, including the human disease referred to as ‘sleeping sickness’ and the animal diseases such as nagana, surra and dourine, are neglected vector-borne diseases that after years of research still need improved diagnosis and chemotherapy. Advances in proteomics offer new tools to define biomarkers, whose expression may reflect host–parasite interactions occurring during the infection. In this review, the authors first describe the current diagnostic tools used to detect a trypanosome infection during field surveys, and then discuss their interests, limits and further evolutions. The authors also report on the contribution of molecular diagnostics, and the recent advances and developments that make it suitable for fieldwork. The authors then explore the recent uses of proteomics technology to define host and parasite biomarkers that allow detection of the infection, the power and constraints of the technology. The authors conclude by discussing the urgent need to use the biomarkers discovered in order to develop tools to improve trypanosomiasis control in the near future.     

The variable roads to sacrifice: Isotopic investigations of human remains from Chotuna‐Huaca de los Sacrificios,Lambayeque, Peru

This study investigates two key variables—residential context and subsistence—among sacrificial victims dating to the Late Horizon (A.D. 1450–1532) in the Huaca de los Sacrificios at the Chotuna‐Chornancap Archaeological Complex in north coastal Peru. We investigate whether aspects of sacrifice in this distant coastal province mirrored that found in Inca heartland contexts such as the capacocha, or remained more typical of coastal sacrificial traditions. Stable carbon, nitrogen, and oxygen isotope values were characterized in bone carbonate, bone collagen, and hair keratin to estimate geographic residence during the decade before death and diet in the decade, versus months, before death. Bone δ¹⁸O_carbonate values have a mean (±SD) of 26.8 ± 1.1%, bone δ¹³C_carbonate values ?6.7 ± 1.7%, and bone δ¹³C_collagen values 11.8 ± 1.3%; bone δ¹⁵N_collagen values have a mean of 11.5 ± 1.3%. Combined hair δ¹³C_keratin values have a mean of ?12.8 ± 1.6%, and hair δ¹⁵N_keratin values 10.8 ± 1.3%. In contrast to contemporaneous coastal and highland contexts, we are unable to identify immigrants among the sacrificed individuals or changes in diet that indicate provisioning with a standardized diet leading up to death. Instead, results suggest that victims were local to the area, but consumed moderately variable diets consistent with local subsistence patterns. These findings suggest a distinct pattern of human sacrifice in the Late Horizon and underscore the regional and temporal variation in sacrificial practices in the central Andes. Am J Phys Anthropol 151:22–37, 2013. © 2013 Wiley Periodicals, Inc.     

Tracing past human male movements in northern/eastern Africa and western Eurasia: new clues from Y-chromosomal haplogroups E-M78 and J-M12

Detailed population data were obtained on the distribution of novel biallelic markers that finely dissect the human Y-chromosome haplogroup E-M78. Among 6,501 Y chromosomes sampled in 81 human populations worldwide, we found 517 E-M78 chromosomes and assigned them to 10 subhaplogroups. Eleven microsatellite loci were used to further evaluate subhaplogroup internal diversification. The geographic and quantitative analyses of haplogroup and microsatellite diversity is strongly suggestive of a northeastern African origin of E-M78, with a corridor for bidirectional migrations between northeastern and eastern Africa (at least 2 episodes between 23.9-17.3 ky and 18.0-5.9 ky ago), trans-Mediterranean migrations directly from northern Africa to Europe (mainly in the last 13.0 ky), and flow from northeastern Africa to western Asia between 20.0 and 6.8 ky ago. A single clade within E-M78 (E-V13) highlights a range expansion in the Bronze Age of southeastern Europe, which is also detected by haplogroup J-M12. Phylogeography pattern of molecular radiation and coalescence estimates for both haplogroups are similar and reveal that the genetic landscape of this region is, to a large extent, the consequence of a recent population growth in situ rather than the result of a mere flow of western Asian migrants in the early Neolithic. Our results not only provide a refinement of previous evolutionary hypotheses but also well-defined time frames for past human movements both in northern/eastern Africa and western Eurasia.     

Monitor lizards: a pan-African check-list of their zoogeography (Sauria: Varanidae: Polydaedalus)

Aim This goal of this paper is to present an up‐to‐date, accurate check‐list and distribution of the monitor lizards on the African continent. No such list of their distribution has been attempted since Robert F. Mertens' (1942) treatise (Abhandlungen Senckenbergischen Naturforschenden Gesellschaft, 462 , 465 , 466 ). Location The localities included herein are all countries on the African continent, and adjacent islands, with a list of Varanus known to Yemen and Saudi Arabian Republics included for clarity. One fossil Varanus rusingensis is included, as it is the first, and only described, fossil African Varanus known. Methods Locality records were reviewed from literature sources, museum voucher specimens, personal comments, field observations and photographic records. Results A summation of 3,268 locality records are included herein from the methods listed, with maps depicting these records. Main conclusions From the locality records listed herein, it is evident that the Nile monitor (V. niloticus) has the widest distribution, and that the Yemen monitor (V. yemenensis) has the most restricted distribution; paradoxically, both features may be indicative of their relic habitation on the African continent.