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Determining infectious cross-transmission events in healthcare settings involves manual surveillance of case clusters by infection control personnel, followed by strain typing of clinical/environmental isolates suspected in said clusters. Recent advances in genomic sequencing and cloud computing now allow for the rapid molecular typing of infecting isolates.
To facilitate rapid recognition of transmission clusters, we aimed to assess infection control surveillance using whole-genome sequencing (WGS) of microbial pathogens to identify cross-transmission events for epidemiologic review.
Clinical isolates of Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, and Klebsiella pneumoniae were obtained prospectively at an academic medical center, from September 1, 2016, to September 30, 2017. Isolate genomes were sequenced, followed by single-nucleotide variant analysis; a cloud-computing platform was used for whole-genome sequence analysis and cluster identification.
Most strains of the 4 studied pathogens were unrelated, and 34 potential transmission clusters were present. The characteristics of the potential clusters were complex and likely not identifiable by traditional surveillance alone. Notably, only 1 cluster had been suspected by routine manual surveillance.
Our work supports the assertion that integration of genomic and clinical epidemiologic data can augment infection control surveillance for both the identification of cross-transmission events and the inclusion of missed and exclusion of misidentified outbreaks (ie, false alarms). The integration of clinical data is essential to prioritize suspect clusters for investigation, and for existing infections, a timely review of both the clinical and WGS results can hold promise to reduce HAIs. A richer understanding of cross-transmission events within healthcare settings will require the expansion of current surveillance approaches.
The Lese are subsistence farmers living in the Ituri Forest of north-east Zaïre. They exhibit significant birth seasonality, with lowest frequencies of conception when food production is least, nutritional status is low and ovarian function, as measured by salivary steroid hormone levels, is reduced. Efe pygmy foragers, who live in the same geographical area but are less dependent on cultivated foods and have a more flexible life style, do not exhibit frequent fluctuations in nutritional status nor significant birth seasonality. These findings support a model of birth seasonality relating climatic variables to variation in fertility through a causal chain linking rainfall to food production to energy balance to ovarian function to fertility. The model, which emphasises an ecological approach to the study of human reproduction, should have broad applicability since seasonality of food production and energy balance is widespread geographically and across a wide variety of economies and cultures.
We hypothesized that among reproductive-age women consuming large quantities of tea, the production of estradiol would be suppressed. It has been shown that catechins and theaflavines, the major constituents of tea, inhibit aromatase, an enzyme which catalyses the conversion of androgens to oestrogens. Our study included Polish women living in urban (n 61) and rural (n 48) areas. Women collected daily saliva samples for one complete menstrual cycle and filled out dietary questionnaires. Saliva samples were analysed by RIA for concentration of 17β-estradiol (E2). Women with high (above the median) average daily consumption of black tea had reduced levels of salivary E2 in comparison with women who drank less black tea (below the median). This effect was observed within the whole study group, as well as separately within urban (P=0·0006) and rural (P=0·013) groups. High intake of the sum of subclasses of tea catechins and epigallocatechin gallate, assessed using the United States Department of Agriculture database (http://www.nal.usda.gov), was also associated with lower concentrations of E2 within all women (P=0·01 and P=0·0001, respectively) and within the urban group (P=0·0001 and P0·004, respectively). Similar relationships were observed between the sum of subclasses of theaflavines and thearubigines and E2 levels for the whole group (P=0·002) and for urban women (P=0·02). Women with high consumption of tea had lower levels of E2 concentration throughout the entire menstrual cycle. These results may have implications for reducing hormone-related cancer risk by a relatively easy dietary intervention.
The proximate causes of the contraceptive effect of lactation are still a matter of productive debate. This study sought to disentangle the relative impact that intense breast-feeding practices and maternal nutrition have on the regulation of ovarian function in nursing women. A mixed-longitudinal, direct-observational, prospective study was conducted of the return to postpartum fecundity in 113 breast-feeding, well-nourished Toba women. A sub-sample of 70 women provided data on nursing behaviour, daily activities, diet quality and urinary levels of oestrone and progesterone metabolites. Well-nourished, intensively breast-feeding Toba women experienced a relatively short period of lactational amenorrhoea (10·2±4·3 months) and a high lifetime fertility (TFR=6·7 live births/woman). Duration of lactational amenorrhoea was not correlated with any of the nursing parameters under study or with static measures of maternal nutritional status. The results indicated that the pattern of resumption of postpartum fertility could be explained, at least partly, by differences in individual metabolic budgets. Toba women resumed postpartum ovulation after a period of sustained positive energy balance. As the relative metabolic load hypothesis suggests, the variable effect of lactation on postpartum fertility may not depend on the intensity of nursing per se but rather on the energetic stress that lactation represents for the individual mother.
The study of human reproductive ecology has in recent years greatly expanded our appreciation of the natural variability of human reproductive physiology. In particular, gonadal function in both males and females has been shown to occur along a broad continuum of variation, both within and between individuals and between populations. Furthermore, such variation has been shown to be interpretable as a healthy, adaptive response to ecological conditions (Ellison et al., 1993a; Ellison 1994, 1995). In keeping with the broader perspective of Darwinian medicine (Ewald, 1980; Nesse & Williams, 1994), the perspective of reproductive ecology has entailed making a distinction between adaptive responses to stressful situations and the etiology of those situations themselves. Under energetic stress, for example, it may be advantageous for ovarian function to be suppressed. That does not mean that energetic stress itself is advantageous. Seeking to treat suppressed ovarian function under these conditions as if it were a pathology, rather than seeking to relieve the energetic stress, would imply a basic misunderstanding of the problem, its etiology, and its appropriate treatment. It is only recently, for example, that clinicians have begun to realize that the amenorrhea associated with athletic activity in many women is not itself a pathology to be rectified by “driving” cycles of endometrial maturation with exogenous steroids.
Few fields of inquiry draw from as diverse an array of disciplines as the study of human fertility. Contributions come from sociology, public health, medicine, demography, political science, economics, and anthropology, each discipline bringing to bear its own particular perspectives and theoretical agenda. The perspective of the biological anthropologist among these others is unique in two respects: the central position of evolutionary theory and evolutionary history in anthropological thinking, and the commitment to understanding human fertility, its determinants and consequences, as part of an integrated species biology. These two elements give rise to the two primary motivations of biological anthropologists for studying human fertility.
The first motivation is to understand as fully as possible our evolutionary past, both the history of change that we and our phyletic relatives have undergone and the forces and constraints that have shaped its course. Understanding the reproductive biology of our species is fundamental to that effort, since in its essentials natural selection can be broken down into variability in the processes of birth and death. If we can fully comprehend the way in which our fertility is regulated by physiological, ecological and social mechanisms, we will be in a better position to elucidate critical junctures of human evolution, such as the transition to subsistence horticulture, the transition to cooperative hunting and gathering societies, or even the original diversion from other hominoid lines.
The Later Bronze Age site at Black Patch consisted of hut platforms and enclosures set in a system of rectangular fields. The settlement area is overlooked by round barrows. Area and sample excavations of the settlement revealed circular huts and activity areas within a C-14 date range of 1070 ± 70 bc–830 ± 80 bc. Extensive economic data in the form of seeds, animal bones, foreign stones and artefacts were recovered. These formed the basis of an economic resource-area analysis undertaken around Black Patch and other contemporary occupation sites on the South Downs. From this an economic activity model is proposed.
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