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Populations on the edge of a species' distribution may represent an important source of adaptive diversity, yet these populations tend to be more fragmented and are more likely to be geographically isolated. Lack of genetic exchanges between such populations, due to barriers to animal movement, can not only compromise adaptive potential but also lead to the fixation of deleterious alleles. The south-eastern edge of chimpanzee distribution is particularly fragmented, and conflicting hypotheses have been proposed about population connectivity and viability. To address this uncertainty, we generated both mitochondrial and MiSeq-based microsatellite genotypes for 290 individuals ranging across western Tanzania. While shared mitochondrial haplotypes confirmed historical gene flow, our microsatellite analyses revealed two distinct clusters, suggesting two populations currently isolated from one another. However, we found evidence of high levels of gene flow maintained within each of these clusters, one of which covers an 18,000 km 2 ecosystem. Landscape genetic analyses confirmed the presence of barriers to gene flow with rivers and bare habitats highly restricting chimpanzee movement. Our study demonstrates how advances in sequencing technologies, combined with the development of landscape genetics approaches, can resolve ambiguities in the genetic history of critical populations and better inform conservation efforts of endangered species., (© 2023 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.)

Aims and Objectives: The case study evaluated the Second Life perceived usability and the decision-making of insulin administration via situational awareness at two different simulation freezes during Second Life simulation., Background: Due to safety issues stemming from nursing knowledge deficits of insulin administration, the use of simulation via practice in a virtual immersive environment, Second Life was evaluated in a case study of practicing nurses., Design: This case study used a single convenience group, post-test design., Methods: Perceived usability was evaluated using the System Usability Scale. Evaluation of decision-making was evaluated via Situational Awareness Score at two simulation freezes in the Second Life simulation with practicing nurses (n = 12)., Results: Nurses with more years of practice reported difficulty in using Second Life. As age increased, the total Situational Awareness Score decreased. Day shift nurses were more likely to obtain a High Situational Awareness Score., Conclusions: Although usability was nearly obtained, virtual immersive environments for nurses has promise to provide practice in aiding clinical decision-making., Relevance to Clinical Practice: Finding a new platform to allow all nurses to practice difficult clinical decisions is key. A virtual immersive environment, like Second Life, can provide simulation for nurses to practice making such difficult decisions., (© 2014 John Wiley & Sons Ltd.)

Objective: To identify risk factors for uncomplicated malaria in highland areas of East Africa at higher risk of malaria epidemics, in order to design appropriate interventions., Methods: Prospective, population-based, case-control study in the Nandi Hills, a highland area of western Kenya, to identify environmental, sociodemographic and behavioural factors associated with clinical malaria. Data were collected using field observation, a structured questionnaire, and a global positioning system device., Results: We interviewed 488 cases of slide-confirmed malaria and 980 age-matched controls. Multivariate analyses associated higher malaria risk with living <250 m of a forest [OR = 3.3 (95% CI 1.5, 7.1)], <250 m of a swamp [2.8 (1.3, 5.9)], <200 m of maize fields [2.0 (1.2, 3.4)], in the absence of trees <200 m [1.6 (1.2, 2.2)], on flat land [1.6 (1.2, 2.2)], in houses without ceilings [1.5 (1.1, 2.2)], in houses with a separate kitchen building [1.8 (1.4, 2.3)] and in households where the female household head had no education [1.9 (1.1, 3.1)]. Travelling out of the study site [2.2 (1.2, 4.1)] was also associated with increased risk. CONCLUSIONS; In this East African highland area, risk of developing uncomplicated malaria was multifactorial with a risk factor profile similar to that in endemic regions. Households within close proximity to forest and swamp borders are at higher risk of malaria and should be included in indoor residual spraying campaigns.

Hepatitis C virus (HCV) infection is gaining increasing attention as a global health crisis. Egypt reports the highest prevalence of HCV worldwide, ranging from 6% to more than 40% among regions and demographic groups. Predicting the impact of the epidemic has been difficult because of the long-latency period and low-resource setting. Accordingly, we sought to estimate historic incidence and predict the future impact of HCV using Markov simulation modelling techniques. Age-specific HCV incidence rates (IRs) were estimated using previously acquired age-specific HCV prevalence data. Data for this analysis were from a highly detailed, community-based seroprevalence study from 2003. Future HCV-related morbidity and mortality were estimated using a computer cohort simulation of HCV natural history in the Egyptian population. Population and natural history parameters were defined using results from a meta-analysis and existing comprehensive literature reviews. Incidence model estimates ranged from 2.01 to 25.47 HCV cases per 1000 person-years (PYs). The highest IRs were calculated among those over 35 years of age. Our Markov model predicted 127,821 deaths from chronic liver disease and 117,556 deaths from hepatocellular carcinoma in Egypt over the next 20 years. During this period, it was estimated that HCV would yield 750,210 PY of decompensated cirrhosis, 132,894 PY of hepatocellular carcinoma, and a total loss of 32.86 million years of life compared to a non-infected cohort. Our results support the claim of high HCV incidence in Egypt and suggest that HCV may lead to a substantial health and, consequently, economic burden over the next 10-20 years.

Endemic Burkitt's lymphoma (BL) is the most common paediatric malignancy in equatorial Africa and was originally shown to occur at high-incidence rates in regions where malaria transmission is holoendemic. New ecological models of malaria that are based on both parasite prevalence and disease have been described. In this study, we examined district level data collected from paediatric BL cases in Kenya from 1988 through 1997 and assessed whether the distribution of district level incidence rates could be explained by new ecologic estimates of malaria risk. Chi-square tests and log-linear regression models were used to evaluate these associations. An association with tribe of origin as a factor also was examined. The 10-year average annual incidence rate (IR) for Kenya was 0.61 per 100,000 children. Incidence rates varied by malaria transmission intensity as follows: low malaria risk (BL IR = 0.39), arid/seasonal (0.25), highland (0.66), endemic coast (0.68), and endemic lake (1.23) (chi(2) = 11.32, P = 0.002). In a log-linear model, BL rates were 3.5 times greater in regions with chronic and intense malaria transmission intensity than in regions with no or sporadic malaria transmission (odds ratio = 3.47, 95% confidence interval = 1.30-9.30), regardless of tribe. Although crude tribe-specific incidence rates ranged between 0.0 and 3.26, tribe was not associated with BL after controlling for malaria. These findings support the aetiologic role of intense malaria transmission intensity in BL.

Background: Use of insecticide-treated nets (ITNs) has become a central focus for the Roll Back Malaria campaign, and many countries in Africa have now embarked on large-scale public health programmes aimed at making ITNs available to those at greatest risk. However, the effectiveness of these programmes has rarely been evaluated., Method: We conducted a cross-sectional survey to assess the impact of an ITN social marketing programme on Plasmodium falciparum infection and anaemia among children in urban Malawi., Results: Knowledge of ITNs was high; however, only 42% of the children surveyed reported to have used an ITN the previous night. Nevertheless, 17% (295/1721) of children had a positive P. falciparum smear at enrolment. Use of ITNs was associated with 52% protective efficacy against Plasmodium parasitemia. More than two-thirds of children were anaemic, yet the mean haemoglobin concentration was significantly higher in children using ITNs than in those not using nets. ITN use was associated with wealth, as poorer households were 60% less likely to use treated nets., Conclusion: Although ITN social marketing programmes have the potential of improving malaria control and prevention, additional efforts are required to reach those for whom even subsidized nets are still too expensive.

Background: Water supply improvements generally reduce the incidence of diarrhoea. However, populations with limited access to a safe water supply may continue to draw water from unimproved sources, thereby increasing their risk of diarrhoea. Furthermore, young children who are not breastfed may be even more susceptible to water-borne diarrhoeal pathogens. Our study explored the interactive protective effects against diarrhoea of exclusively using improved water sources and breastfeeding among children in rural Mali., Methods: Interviews were conducted with parents or guardians of children under 7 years of age in seven villages with access to a variety of water supplies. Water sources used, breastfeeding status, demographics and recent diarrhoea symptoms were determined for 1117 children. The cross-sectional findings were used to compare diarrhoea prevalence among exclusive and non-exclusive users of improved water sources. Variation in prevalence by age and exclusive breastfeeding status was evaluated using chi-square and multivariate analyses., Results: Children whose water was drawn exclusively from wells had a significantly lower prevalence of diarrhoea as compared with children whose water was drawn from a spring or stream (5.9% vs. 8.7%; P=0.04). The exclusive use of improved water sources had no impact on diarrhoea prevalence among children who were exclusively breastfed. Similarly, the strongest protective effect was observed among children who were not exclusively breastfed., Conclusions: Our results indicate that using surface water as a primary or secondary water source exposes children to greater risk of diarrhoeal disease than using only improved sources such as wells. It is particularly beneficial for young children who are not exclusively breastfed to be supplied with water drawn from improved sources.

To determine risk factors associated with dengue (DEN) virus infection among residents of Santa Clara, Peru, a rural Amazonian village near Iquitos, a cross-sectional serological, epidemiological and environmental survey was conducted. Demographic, social and behavioural information was obtained by standardized questionnaire from 1225 Santa Clara residents (61.3%) aged 5 years or older. Additional data were obtained on the environmental variables and immature mosquito species and abundance surrounding each household (n = 248). Sera that had been collected previously by the Peruvian Ministry of Health from residents were tested by an enzyme-linked immunosorbent assay (ELISA) for DEN virus IgG antibody. Antibody identity was verified as DEN by plaque reduction neutralization test. Data on individuals were analysed by univariate and multivariable methods, and independent sample t-tests. Spatial clustering was evaluated by comparing distances among DEN positive households. Overall, antibody prevalence was 29.4 % and more than doubled from the youngest to the oldest age groups, but did not differ by sex. Curiously, length of residence in Santa Clara was negatively associated with DEN virus antibodies. More frequent travel to Iquitos was positively associated with seroprevalence. Residents who obtained water from a river source rather than a local well also had significantly higher antibody prevalence. None of the environmental variables measured at each household corresponded to the patterns of antibody distribution. Of the larval mosquitoes found around residences, all were determined to be species other than Aedes. No evidence of spatial autocorrelation among antibody-positive households was detected. These results strongly suggested that recent DEN virus transmission did not occur in the village and that most infections of residents of this rural village were acquired while visiting the city of Iquitos.

Early diagnosis of malaria followed by appropriate treatment can help reduce related morbidity and mortality as well as interrupt transmission. Previous studies of household responses to malaria have tended to focus on endemic areas where the burden of this disease is greatest. With the apparent increasing frequency of epidemics in African highlands, a better understanding of treatment behaviours in areas of unstable transmission may be important to future public health interventions. This study was undertaken following a serious epidemic of malaria in the highlands of south-western Uganda. Our objectives were to characterize actions taken by both adults and caretakers of children < or =5 years old during their most recent episode of self-diagnosed malaria, and to identify factors that were associated with prompt treatment at a health facility. A survey of 300 households selected in a 2-stage cluster sampling procedure produced 453 adult respondents and 133 caretakers of children < or =5 years old. We found that almost 65% of adults and 62% of children who had experienced an episode of malaria in the last year (most during the epidemic) had sought treatment from a health facility first as opposed to self-treatment. Most of these people had visited the health facility within 1 day of symptom onset. By the end of their malaria episode, over 87% of adults and 80% of children had visited a health facility at least once. Factors associated with prompt presentation at a health facility included severity of illness, household proximity to a health facility, and knowledge of malaria prevention methods. Our results indicate that there is an important role for the formal health care system in mitigating morbidity and mortality and reducing transmission during malaria epidemics in Uganda.

As highland regions of Africa historically have been considered free of malaria, recent epidemics in these areas have raised concerns that high elevation malaria transmission may be increasing. Hypotheses about the reasons for this include changes in climate, land use and demographic patterns. We investigated the effect of land use change on malaria transmission in the south-western highlands of Uganda. From December 1997 to July 1998, we compared mosquito density, biting rates, sporozoite rates and entomological inoculation rates between 8 villages located along natural papyrus swamps and 8 villages located along swamps that have been drained and cultivated. Since vegetation changes affect evapotranspiration patterns and, thus, local climate, we also investigated differences in temperature, humidity and saturation deficit between natural and cultivated swamps. We found that on average all malaria indices were higher near cultivated swamps, although differences between cultivated and natural swamps were not statistically significant. However, maximum and minimum temperature were significantly higher in communities bordering cultivated swamps. In multivariate analysis using a generalized estimating equation approach to Poisson regression, the average minimum temperature of a village was significantly associated with the number of Anopheles gambiae s.l. per house after adjustment for potential confounding variables. It appears that replacement of natural swamp vegetation with agricultural crops has led to increased temperatures, which may be responsible for elevated malaria transmission risk in cultivated areas.