Use of dried blood spots to define antibody response to the Strongyloides stercoralis recombinant antigen NIE

An approach to improve the diagnosis of Strongyloides stercoralis infection is the use of serologic assays utilising the NIE antigen from S. stercoralis, with good diagnostic sensitivity and excellent specificity reported. Detection of antibody eluted from dried blood spots (DBS) has shown utility in large-scale seroepidemiological studies for a range of conditions and is appealing for use with children where sample collection is difficult. We adapted an existing NIE-enzyme linked immunosorbent assay (ELISA) for the testing of strongyloides antibody response on DBS, and evaluated it in a population screening and mass drug administration programme (MDA) for strongyloidiasis conducted in an Australian indigenous community. Study participants were treated with 200 μg/kg ivermectin (>15 kg) or 3× 400 mg albendazole (<15 kg). The sensitivity of the NIE DBS-ELISA was determined by receiver operator characteristic (ROC) analysis to be 85.7%. A total of 214 DBS were collected from 184 participants across two screening and MDA encounters. A total of 27 of 164 participants (16.5%) tested positive for S. stercoralis NIE-DBS prior to MDA treatment, and 6 of 50 participants (12.0%) tested positive after treatment. These prevalence values are similar to those documented by standard serology in the same community. For 30 participants where a DBS was collected at both MDA 1 and 2, a significant decline in ELISA values was evident post treatment (0.12–0.02, p = 0.0012). These results are in agreement with previous studies documenting the high seroprevalence of S. stercoralis in remote Australian Indigenous communities, and suggest that collection of dried blood spots may be a useful approach for field diagnosis of S. stercoralis seroprevalence.     

Phylogenetic reconstruction of Bantu kinship challenges Main Sequence Theory of human social evolution

Kinship provides the fundamental structure of human society: descent determines the inheritance pattern between generations, whereas residence rules govern the location a couple moves to after they marry. In turn, descent and residence patterns determine other key relationships such as alliance, trade, and marriage partners. Hunter-gatherer kinship patterns are viewed as flexible, whereas agricultural societies are thought to have developed much more stable kinship patterns as they expanded during the Holocene. Among the Bantu farmers of sub-Saharan Africa, the ancestral kinship patterns present at the beginning of the expansion are hotly contested, with some arguing for matrilineal and matrilocal patterns, whereas others maintain that any kind of lineality or sex-biased dispersal only emerged much later. Here, we use Bayesian phylogenetic methods to uncover the history of Bantu kinship patterns and trace the interplay between descent and residence systems. The results suggest a number of switches in both descent and residence patterns as Bantu farming spread, but that the first Bantu populations were patrilocal with patrilineal descent. Across the phylogeny, a change in descent triggered a switch away from patrifocal kinship, whereas a change in residence triggered a switch back from matrifocal kinship. These results challenge “Main Sequence Theory,” which maintains that changes in residence rules precede change in other social structures. We also indicate the trajectory of kinship change, shedding new light on how this fundamental structure of society developed as farming spread across the globe during the Neolithic.Kinship is the key structure underlying human society: descent determines how wealth, land, and position are inherited across generations, whereas residence describes the rules governing where a couple should move to once they are married (1). In turn, descent and residence patterns determine other key relationships within society such as alliance, trade, and marriage partners (2). Contemporary hunter-gatherer societies, which are often considered a model for preagricultural human societies, are predominantly bilateral, tracing descent through both lines, and multilocal, with each couple choosing where to live (2–4, but see ref. 5), allowing for flexibility in those societies. In the last 10,000 years, however, a number of groups developed agriculture, which led to the expansion of food production techniques, cultures, and in some cases their populations too (6). The emergence of farming is thought to have coincided with more sex-biased dispersal and unilineal kinship (7).From their ancestral homeland in the Benue valley in Eastern Nigeria 3,000–5,000 BP (8, 9), possibly using a grassland corridor that opened up through the Cameroon rainforest (10, 11), the Bantu undertook one of the great farming expansions of the Neolithic (6). The history of their kinship is therefore key to debates about the fundamental processes that drove the evolution of human society during the Holocene. However, there are disagreements about the ancestral pattern of Bantu kinship and how this evolved through time.Vansina (12) suggests that proto-Bantu society had a bilateral descent and bilocal residence system (definitions in SI Appendix, Table S1) that was adaptive for expanding populations. Based on linguistic reconstruction, such as the proto-Bantu word for “house” being sex neutral, he argues that residence was flexible (13). Hunting required cooperation and mobility, and would be best served by males having a choice about their residence rather than being constrained by unilocality (12). Vansina suggests that only in the 18th or 19th century did unilineal descent and residence patterns begin to emerge, due to increased wealth and the disorder faced by some Bantu-speaking people (12).The second theory proposes a unilineal descent and unilocal residence system in the ancestral Bantu population (14). Hage and Marck argue, based on the linguistic reconstruction of kin terms, that the early Bantu speakers were, in fact, matrilocal and matrilineal (see also ref. 3), and dispute the sex neutrality of the proto-word for “house.” They also suggest that matriliny is consistent with a people that face an external threat experienced as populations expand and colonize new territory, arguing that absent males would trust their sisters, but not their wives, to look after their common lineage interests (15). Crucially, Marck and Bostoen (7) argue that matrifocal Bantu cultures dissolved with residence changing first from matrilocal to patrilocal, thus supporting Divale’s (16) proposal that changes in residence drive changes in inheritance patterns for a migrating population. This suggestion provides support for “Main Sequence Theory,” which proposes that worldwide there is a pattern of change with residence rules driving change in other social structures (2). In particular, Murdock argues “when any social system undergoes change, such change regularly begins with a modification in the rule of residence” (ref. 2, p. 221). Changes in descent follow and are always consistent with the change in residence. Changes in kinship terminology are affected by changes in both residence and descent and may follow some considerable time afterward (2).There is therefore no agreement among researchers about the ancestral states or patterns of change in kinship traits among Bantu societies based on historical linguistic methods. There are a number of problems with relying solely on reconstructions of ancestral vocabulary to infer social organization in the past. First, although linguists use systematic methods of reconstructing proto-forms based on regular sound changes (13, 14), there is still an element of subjectivity in this approach, which can lead different researchers to suggest contradictory results based on the same words (7, 13, 14). Furthermore, the inference of social organization in a past society is a further step removed from this process and assumes a direct relationship between particular words and particular forms of organization. Although it may be possible to reconstruct the sound of a particular lexical item, the meaning of such a word is less clear because of the possibility of semantic shifts (17).Phylogenetic comparative methods, adapted from evolutionary biology, offer an alternative way of reconstructing the evolutionary history of cultural traits such as kinship structures. These techniques map the traits of interest (in this case descent and residence) onto a phylogenetic tree, which represents the way societies are related to each other historically. The likely forms of these traits in past societies can then be inferred by using an explicit statistical model of trait evolution. Importantly, these reconstructions are probabilistic, meaning it is possible to assess how much confidence to place in any particular reconstruction. The likelihood of alternative hypotheses for the pattern of evolution of traits over the tree can then be estimated. Furthermore, performing analyses over a sample of phylogenetic trees can explicitly incorporate uncertainty about the historical relationships between societies. These methods can be used to estimate the cultural history of a language family, even where historical records or archaeological evidence are absent, and have been used to examine the history of residence patterns in both the Indo-European and Austronesian language families (18, 19).The Bantu speaking people of sub-Saharan Africa represent one of the major early farming expansions; the advantage of agricultural food production allowed a single language group to displace and expand into the lands of previous hunter-gatherer populations (6). This process has allowed for language phylogenies of Bantu societies to be generated (9, 20–22), which can be combined with comprehensive data on extant kinship patterns across a large number of Bantu cultures (23, 24) to infer historical patterns of cultural evolutionary change. A previous attempt to infer the ancestral state of descent for the original Bantu population (25, 26) was inconclusive, possibly because of the small sample size, the single phylogeny (20), or the maximum likelihood methods used.Here, we advance previous attempts to reconstruct the kinship traits across the Bantu language family by applying Bayesian phylogenetic comparative methods (27–29) to a dataset of 122 Bantu ethnolinguistic groups to infer the ancestral state and evolutionary trajectory of Bantu kinship patterns. Analysis of basic vocabulary items (30) has enabled the phylogenetic relationships among more than 500 Bantu languages to be inferred (9), which has increased the scope for the number of different Bantu cultures that can be analyzed and enabled the incorporation of groups that were underrepresented in previous analyses. In particular, the current sample includes a number of additional societies from the “Northwest” and “Forest West” regions, which may be particularly important in inferring trait states at the earliest nodes in the trees. Furthermore, Bayesian phylogenetic methods, which can incorporate uncertainty about the phylogenetic relationships between cultures, provide a more accurate picture of the inferences that can be drawn from comparative data. In this way, it is possible to infer the ancestral states of kinship traits and, hence, reconstruct the cultural history of the Bantu expansion, which means it is possible to estimate the likely order of trait change and test whether changes in residence rules precede changes in inheritance patterns as proposed by Main Sequence Theory (2, 7, 16).     

Minimal‐access colorectal surgery is associated with fewer adhesion‐related admissions than open surgery

Background:

This study aimed to describe national intermediate‐term admission rates for incisional hernia or clinically apparent adhesions following colorectal surgery, and to compare rates following laparoscopic and open approaches.

Methods:

Patients undergoing primary colorectal resection between 2002 and 2008 were included from the Hospital Episode Statistics database. Subsequent inpatient admissions were extracted for up to 3 years after the initial operation or to the end of the study period. Outcomes examined were admissions with a diagnosis of, or operative interventions for, incisional hernia or adhesions.

Results:

A total of 187 148 patients were included between 2002 and 2008, with median follow‐up of 31·8 (interquartile range 13·1–35·3) months. Some 8885 (4·7 per cent) of these patients were admitted with a diagnosis of, or underwent a repair of, an incisional hernia. In multiple regression analysis, use of laparoscopy was not a predictor of operative intervention for incisional hernia (odds ratio 1·09, 95 per cent confidence interval (c.i.) 0·99 to 1·21; P = 0·083). Some 15 125 (8·1 per cent) of the patients were admitted with a diagnosis of adhesions or had a procedure for division of adhesions. Overall, 3·5 per cent (6637 of 187 148) of patients underwent adhesiolysis. Patients selected for a laparoscopic procedure had lower rates of admission for adhesions (6·3 per cent (692 of 11 013) for laparoscopic versus 8·2 per cent (14 433 of 176 135) for open surgery; P < 0·001) and reintervention for adhesions (2·8 per cent (305 of 11 013) versus 3·6 per cent (6325 of 176 135) respectively; P < 0·001) than those undergoing an open procedure. In multiple regression analysis, patients selected for a laparoscopic procedure had lower subsequent intervention rates for adhesions (odds ratio 0·80, 95 per cent c.i. 0·71 to 0·90; P < 0·001).

Discussion:

Patients undergoing colorectal resection who are selected for the laparoscopic approach have a lower risk of developing clinically significant adhesions. Copyright © 2012 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.     

The effect of tobacco control policies on smoking prevalence and smoking-attributable deaths. Findings from the Netherlands SimSmoke Tobacco Control Policy Simulation Model

Aim To develop a simulation model projecting the effect of tobacco control policies in the Netherlands on smoking prevalence and smoking‐attributable deaths. Design, setting and participants Netherlands SimSmoke—an adapted version of the SimSmoke simulation model of tobacco control policy—uses population, smoking rates and tobacco control policy data for the Netherlands to predict the effect of seven types of policies: taxes, smoke‐free legislation, mass media, advertising bans, health warnings, cessation treatment and youth access policies. Measurements Outcome measures were smoking prevalence and smoking‐attributable deaths. Findings With a comprehensive set of policies, as recommended by MPOWER, smoking prevalence can be decreased by as much as 21% in the first year, increasing to a 35% reduction in the next 20 years and almost 40% by 30 years. By 2040, 7706 deaths can be averted in that year alone with the stronger set of policies. Without effective tobacco control policies, almost a million lives will be lost to tobacco‐related diseases between 2011 and 2040. Of those, 145 000 can be saved with a comprehensive tobacco control package. Conclusions Smoking prevalence and smoking‐attributable deaths in the Netherlands can be reduced substantially through tax increases, smoke‐free legislation, high‐intensity media campaigns, stronger advertising bans and health warnings, comprehensive cessation treatment and youth access laws. The implementation of these FCTC/MPOWER recommended policies could be expected to show similar or even larger relative reductions in smoking prevalence in other countries which currently have weak policies.