Quantification of HTLV-I proviral load in experimentally infected rabbits

BACKGROUND: Levels of proviral load in HTLV-1 infected patients correlate with clinical outcome and are reasonably prognostic. Adaptation of proviral load measurement techniques is examined here for use in an experimental rabbit model of HTLV-1 infection. Initial efforts sought to correlate proviral load with route and dose of inoculation and with clinical outcome in this model. These methods contribute to our continuing goal of using the model to test treatments that alleviate virus infection. RESULTS: A real-time PCR assay was used to measure proviral load in blood and tissue samples from a series of rabbits infected using HTLV-1 inocula prepared as either cell-free virus particles, infected cells or blood, or by naked DNA injection. Proviral loads from asymptomatically infected rabbits showed levels corresponding to those reported for human patients with clinically silent HTLV-1 infections. Proviral load was comparably increased in 50% of experimentally infected rabbits that developed either spontaneous benign or malignant tumors while infected. Similarly elevated provirus was found in organs of rabbits with experimentally induced acute leukemia/lymphoma-like disease. Levels of provirus in organs taken at necropsy varied widely suggesting that reservoirs of infections exist in non-lymphoid organs not traditionally thought to be targets for HTLV-1. CONCLUSION: Proviral load measurement is a valuable enhancement to the rabbit model for HTLV-1 infection providing a metric to monitor clinical status of the infected animals as well as a means for the testing of treatment to combat infection. In some cases proviral load in blood did not reflect organ proviral levels, revealing a limitation of this method for monitoring health status of HTLV-1 infected individuals

Spatial Relationships between Small-Holder Farms Coupled With Livestock Management Practices Are Correlated With the Distribution of Antibiotic Resistant Bacteria in Northern Tanzania

We examined the spatial distribution of antibiotic-resistant coliform bacteria amongst livestock from three distinct cultural groups, where group-level differences in practices (e.g., antibiotic use) may influence the magnitude of antibiotic resistance, while livestock interactions (e.g., mixing herds, shared markets) between these locations may reduce heterogeneity in the distribution of antibiotic resistant bacteria. Data was collected as part of a larger study of antibiotic-resistance in northern Tanzania. Simple regression and generalized linear regression were used to assess livestock management and care practices in relation to the prevalence of multidrug-resistant (MDR) coliform bacteria. Simple and multivariable logistic regression were then used to identify how different management practices affected the odds of households being found within MDR “hotspots.” Households that had a higher median neighbourhood value within a 3000 m radius showed a significant positive correlation with livestock MDR prevalence (β = 4.33, 95% CI: 2.41–6.32). Households were more likely to be found within hotspots if they had taken measures to avoid disease (Adjusted Odds Ratio (AOR) 1.53, CI: 1.08—2.18), and if they reported traveling less than a day to reach the market (AOR 2.66, CI: 1.18—6.01). Hotspot membership was less likely when a greater number of livestock were kept at home (AOR 0.81, CI: 0.69–0.95), if livestock were vaccinated (AOR 0.32, CI: 0.21—0.51), or if distance to nearest village was greater (AOR 0.46, CI: 0.36–0.59). The probability of MDR increases when herds are mixed, consistent with evidence for passive transmission of resistant bacteria between animals. Reduced MDR with vaccination is consistent with many studies showing reduced antibiotic use with less disease burden. The neighbourhood effect has implications for design of intervention studies

Correction to: \u27Greater Wealth Inequality, Less Polygyny: Rethinking the Polygyny Threshold Model\u27

With apologies, an incorrect author list was given in the article. An additional author, Chris von Rueden, (Jepson School of Leadership Studies, University of Richmond) also contributed to this work. Author Ryan Schacht's affiliation was out-of-date. His correct affiliation is: Department of Anthropology, East Carolina University

Kinship ties across the lifespan in human communities

A hypothesis for the evolution of long post-reproductive lifespans in the human lineage involves asymmetries in relatedness between young immigrant females and the older females in their new groups. In these circumstances, inter-generational reproductive conflicts between younger and older females are predicted to resolve in favour of the younger females, who realize fewer inclusive fitness benefits from ceding reproduction to others. This conceptual model anticipates that immigrants to a community initially have few kin ties to others in the group, gradually showing greater relatedness to group members as they have descendants who remain with them in the group. We examine this prediction in a cross-cultural sample of communities, which vary in their sex-biased dispersal patterns and other aspects of social organization. Drawing on genealogical and demographic data, the analysis provides general but not comprehensive support for the prediction that average relatedness of immigrants to other group members increases as they age. In rare cases, natal members of the community also exhibit age-related increases in relatedness. We also find large variation in the proportion of female group members who are immigrants, beyond simple traditional considerations of patrilocality or matrilocality, which raises questions about the circumstances under which this hypothesis of female competition are met. We consider possible explanations for these heterogenous results, and we address methodological considerations that merit increased attention for research on kinship and reproductive conflict in human societies. This article is part of the theme issue 'The evolution of female-biased kinship in humans and other mammals'

Dimensions of wild yam foraging among a Congo Basin forager population

Over twenty years ago, several anthropologists began to question the ability of foragers to inhabit rainforest environments prior to the advent of agriculture. The current paper tests the hypothesis that foragers could not occupy rainforest environments prior to the development of agriculture. This hypothesis suggests that the major limiting factor to sustained human occupation is the availability of edible carbohydrates in rain forest ecosystems. Edible carbohydrate resources available in rainforests, in particular wild yams, are scarce, exhibit unpredictable distributions and require large handling times. A direct consequence of the ITF hypothesis is the reliance of tropical foragers on domesticated sources of carbohydrates, a pattern that has been documented across tropical environments, is one of necessity. The applicability of these assumptions is tested using wild yam return rate data from the Bofi, a northern Congo Basin forager population. Return rates of wild yams in the current study will demonstrate, in contradiction to the ITF hypothesis, that wild-yams could sustain independent occupation of the Northern Congo Basin rain forests. Furthermore, these results challenge the assumption that the contemporary reliance of tropical foragers on domesticated sources of carbohydrates is born from necessity

LIFE HISTORY THEORY WITHIN THE HUMAN NICHE: CONCEPTUAL CONUNDRUMS, COALESCING COMMENTARIES, AND A CONSIDERATION OF CULTURE

The evolutionary fate of humans is intimately tied to the outcomes of two questions; when and how often should we reproduce? Life history theory can account for “when” and “how often” but, as a biological theory, must be refined when applied within the cultural, economic, and political complexities of the human niche. The process of refining life history theory and method to address patterns of human reproduction frames this three-study dissertation. Addressing the nature of risk within the human niche, the first study employs structural equation modeling techniques to isolate the impacts of varying types of condition-dependent risks on teenage and total fertility rates across 191 countries. Motivating the second study is the necessary integration of life history theory into a unified theory of demography. Applying a fixed effects approach to data from 167 countries and across 40 years, this study models how the main drivers of fertility behavior interact across both space and time. The final study demonstrates the broad applicability of life history theory within the human niche through an examination of the demographic and consumption patterns fueling anthropogenic climate change. Multilevel models using data from 45,000 individuals across 75 nations are specified to determine how local risk and parental investment interact with cultural time orientations to pattern global carbon emissions. To conclude, results of the three studies are revisited to propose areas in which life history theory can continue its expansion within the human niche

Resource availability, mortality, and fertility: a path analytic approach to global life-history variation

Humans exhibit considerable diversity in timing and rate of reproduction. Life-history theory (LHT) suggests that ecological cues of resource richness and survival probabilities shape human phenotypes across populations. Populations experiencing high extrinsic mortality due to uncertainty in resources should exhibit faster life histories. Here we use a path analytic (PA) approach informed by LHT to model the multiple pathways between resources, mortality rates, and reproductive behavior in 191 countries. Resources that account for the most variance in population mortality rates are predicted to explain the most variance in total fertility rates. Results indicate that resources (e.g., calories, sanitation, education, and health-care expenditures) influence fertility rates in paths through communicable and noncommnunicable diseases. Paths acting through communicable disease are more strongly associated with fertility than are paths through noncommunicable diseases. These results suggest that a PA approach may help disaggregate extrinsic and intrinsic mortality factors in cross-cultural analyses. Such knowledge may be useful in developing targeted policies to decrease teenage pregnancy, total fertility rates, and thus issues associated with overpopulation

File 2: Supporting Data used in Model 1 and Model 2- This supplementary file includes all data used in the analyses. Variable names are prefixed by the specific model they were included in (e.g., "model 1) from Life history theory and climate change: resolving population and parental investment paradoxes

Population growth in the next half-century is on pace to raise global carbon emissions by half. Carbon emissions are associated with fertility as a by-product of somatic and parental investment, which is predicted to involve time orientation/preference as a mediating psychological mechanism. Here, we draw upon life-history theory (LHT) to investigate associations between future orientation and fertility, and their impacts on carbon emissions. We argue ‘<i>K</i>-strategy’ life history (LH) in high-income countries has resulted in parental investment behaviours involving future orientation that, paradoxically, promote unsustainable carbon emissions, thereby lowering the Earth's <i>K</i> or carrying capacity. Increasing the rate of approach towards this capacity are ‘<i>r</i>-strategy’ LHs in low-income countries that promote population growth. We explore interactions between future orientation and development that might slow the rate of approach towards global <i>K</i>. Examination of 67 000 individuals across 75 countries suggests that future orientation interacts with the relationship between environmental risk and fertility and with development related parental investment, particularly investment in higher education, to slow population growth and mitigate <i>per capita</i> carbon emissions. Results emphasize that LHT will be an important tool in understanding the demographic and consumption patterns that drive anthropogenic climate change

File 1: Variables Definitions and Model Specifications- This supplementary file contains definitions of variables included in the model, more information and model specifications, and variance accounted for by model 1 from Life history theory and climate change: resolving population and parental investment paradoxes

Population growth in the next half-century is on pace to raise global carbon emissions by half. Carbon emissions are associated with fertility as a by-product of somatic and parental investment, which is predicted to involve time orientation/preference as a mediating psychological mechanism. Here, we draw upon life-history theory (LHT) to investigate associations between future orientation and fertility, and their impacts on carbon emissions. We argue ‘<i>K</i>-strategy’ life history (LH) in high-income countries has resulted in parental investment behaviours involving future orientation that, paradoxically, promote unsustainable carbon emissions, thereby lowering the Earth's <i>K</i> or carrying capacity. Increasing the rate of approach towards this capacity are ‘<i>r</i>-strategy’ LHs in low-income countries that promote population growth. We explore interactions between future orientation and development that might slow the rate of approach towards global <i>K</i>. Examination of 67 000 individuals across 75 countries suggests that future orientation interacts with the relationship between environmental risk and fertility and with development related parental investment, particularly investment in higher education, to slow population growth and mitigate <i>per capita</i> carbon emissions. Results emphasize that LHT will be an important tool in understanding the demographic and consumption patterns that drive anthropogenic climate change

Medical pluralism and livestock health: ethnomedical and biomedical veterinary knowledge among East African agropastoralists

Background: Human and animal health are deeply intertwined in livestock dependent areas. Livestock health contributes to food security and can influence human health through the transmission of zoonotic diseases. In low-income countries diagnosis and treatment of livestock diseases is often carried out by household members who draw upon both ethnoveterinary medicine (EVM) and contemporary veterinary biomedicine (VB). Expertise in these knowledge bases, along with their coexistence, informs treatment and thus ultimately impacts animal and human health. The aim of the current study was to determine how socio-cultural and ecological differences within and between two livestock-keeping populations, the Maasai of northern Tanzania and Koore of southwest Ethiopia, impact expertise in EVM and VB and coexistence of the two knowledge bases. Methods: An ethnoveterinary research project was conducted to examine dimensions of EVM and VB knowledge among the Maasai (N = 142 households) and the Koore (N = 100). Cultural consensus methods were used to quantify expertise and the level of agreement on EVM and VB knowledge. Ordinary least squares regression was used to model patterns of expertise and consensus across groups and to examine associations between knowledge and demographic/sociocultural attributes. Results: Maasai and Koore informants displayed high consensus on EVM but only the Koore displayed consensus on VB knowledge. EVM expertise in the Koore varied across gender, herd size, and level of VB expertise. EVM expertise was highest in the Maasai but was only associated with age. The only factor associated with VB expertise was EVM expertise in the Koore