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Abstract— Variability in infection rates of trematodes Diplostomum pseudospathaceum in 0+ rainbow trout Oncorhynchus mykiss under different hydraulic regimes was studied in the experimental setup with regulated flow rates and environmental heterogeneity. The average infection rate in the conditions of the current was 1.5 times less than that in the stagnant water. An increase of the flow rate from 3.2 to 11.3 cm/s did not result in lower infection rates, while the interindividual variability in the infection rate (coefficient of variation) tended to increase along with changing the still-water conditions (20%) to the high flow rate environments (40%) within the experiment. A decrease in the average infection rate and an increase in the variability within the heterogenous flow of water could indicate the fact that some fish effectively avoid infection. It may be caused by redistribution of cercariae suspended in the water column across microhabitats with different flow rates together with fish behavior which allows them to choose sites with low parasite concentration.

Aim We propose a novel approach that considers taxonomic uniqueness, functional uniqueness and environmental uniqueness and show how it can be used in guiding conservation planning. We illustrate the approach using data for lake biota and environment. Location Lake Puruvesi, Finland. Methods We sampled macrophytes and macroinvertebrates from the same 18 littoral sites. By adapting the original “ecological uniqueness” approach, we used distance-based methods to calculate measures of taxonomic (LCBD–t), functional (LCBD–f) and environmental (LCEH) uniqueness for each site. We also considered the numbers and locations of the sites needed to protect up to 70% of total variation in taxonomic, functional or environmental features in the studied part of the lake. Results Relationships between taxonomic (LCBD–t), functional (LCBD–f) and environmental (LCEH) uniqueness were generally weak, and only the relationship between macrophyte LCBD–t and LCBD–f was statistically significant. Overall, however, if the whole biotic dataset was considered, macroinvertebrate LCBD–f values showed a consistent positive relationship with macrophyte LCBD–f. Depending on the measure of site uniqueness, between one-third to one half of the sites could help protect up to 70% of the ecological uniqueness of the studied part of Lake Puruvesi. Main conclusions Although the dataset examined originated from a large lake system, the approach we proposed here can be applied in different ecosystems and at various spatial scales. An important consideration is that a set of sites has been sampled using the same methods, resulting in species and environmental matrices that can be analysed using the methodological approach proposed here. This framework can be easily applied to grid-based data, sets of islands or sets of forest fragments. We suggest that the approach based on taxonomic, functional and environmental uniqueness will be a useful tool in guiding nature conservation and ecosystem management, especially if associated with meta-system ideas or network thinking. peerReviewed

Children who like to read and write tend to be better at it. This association is typically interpreted as enjoyment impacting engagement in literacy activities, which boosts literacy skills. We fitted direction-of-causation models to partial data of 3690 Finnish twins aged 12. Literacy skills were rated by the twins' teachers and literacy enjoyment by the twins themselves. A bivariate twin model showed substantial genetic influences on literacy skills (70%) and literacy enjoyment (35%). In both skills and enjoyment, shared-environmental influences explained about 20% in each. The best-fitting direction-of-causation model showed that skills impacted enjoyment, while the influence in the other direction was zero. The genetic influences on skills influenced enjoyment, likely via the skills -> enjoyment path. This indicates an active gene-environment correlation: children with an aptitude for good literacy skills are more likely to enjoy reading and seek out literacy activities. To a lesser extent, it was also the shared-environmental influences on children's skills that propagated to influence children's literacy enjoyment. Environmental influences that foster children's literacy skills (e.g., families and schools), also foster children's love for reading and writing. These findings underline the importance of nurturing children's literacy skills. Highlights It's known that how much children enjoy reading and writing and how good they are at it correlates similar to 0.30, but causality remains unknown. We tested the direction of causation in 3690 twins aged 12. Literacy skills impacted literacy enjoyment, but not the other way around. Genetics influence children's literacy skills and how much they like and choose to read and write, indicating genetic niche picking.

Spatial co-occurrence patterns are determined by environmental factors, such as food availability or habitat characteristics and by biotic associations. When resources are limited, competition which implies a dominant hierarchy can shape species assemblage. Here, we study space and time co-occurrence of steppe passerines during the breeding season in a natural steppe habitat, its modulation by environmental filtering, potential biotic interactions and random processes. We applied the joint species distribution model of hierarchical modelling of species community (HMSC) to data on species presence–absence and environmental, temporal and spatial covariates acquired from seven plots in a natural steppe in central Spain during two consecutive years. Our results reveal the patterns of bird species co-occurrence and suggest that this assemblage might be competitively structured. The assemblage appears to be configured around one dominant species, the Eurasian skylark, which establishes principally negative associations with many of the coexistent species. Our results contribute to the understanding of how competition and dominance processes, together with ecological constraints and other biotic associations, shape bird assemblages, Academy of Finland - 309581. European Commission - LIFE Connect Ricotí project LIFE20-NAT/ES/000133, LIFE Ricotí project LIFE15-NAT-ES-000802. European Commission - Horizon 2020 Framework Programme, H2020 Excellent Science, H2020 European Research Council, 856506. Jane ja Aatos Erkon Säätiö - Research Council of Norway through its Centres. Remedinal REMEDINAL-3 from CAM

Refractive error, measured here as mean spherical equivalent (SER), is a complex eye condition caused by both genetic and environmental factors. Individuals with strong positive or negative values of SER require spectacles or other approaches for vision correction. Common genetic risk factors have been identified by genome-wide association studies (GWAS), but a great part of the refractive error heritability is still missing. Some of this heritability may be explained by rare variants (minor allele frequency [MAF] ≤ 0.01.). We performed multiple gene-based association tests of mean Spherical Equivalent with rare variants in exome array data from the Consortium for Refractive Error and Myopia (CREAM). The dataset consisted of over 27,000 total subjects from five cohorts of Indo-European and Eastern Asian ethnicity. We identified 129 unique genes associated with refractive error, many of which were replicated in multiple cohorts. Our best novel candidates included the retina expressed PDCD6IP, the circadian rhythm gene PER3, and P4HTM, which affects eye morphology. Future work will include functional studies and validation. Identification of genes contributing to refractive error and future understanding of their function may lead to better treatment and prevention of refractive errors, which themselves are important risk factors for various blinding conditions. peerReviewed

Aim There has been a wide interest in the effect of biotic interactions on species' occurrences and abundances at large spatial scales, coupled with a vast development of the statistical methods to study them. Still, evidence for whether the effects of within-trophic-level biotic interactions (e.g. competition and heterospecific attraction) are discernible beyond local scales remains inconsistent. Here, we present a novel hypothesis-testing framework based on joint dynamic species distribution models and functional trait similarity to dissect between environmental filtering and biotic interactions. Location France and Finland. Taxon Birds. Methods We estimated species-to-species associations within a trophic level, independent of the main environmental variables (mean temperature and total precipitation) for common species at large spatial scale with joint dynamic species distribution (a multivariate spatiotemporal delta model) models. We created hypotheses based on species' functionality (morphological and/or diet dissimilarity) and habitat preferences about the sign and strength of the pairwise spatiotemporal associations to estimate the extent to which they result from biotic interactions (competition, heterospecific attraction) and/or environmental filtering. Results Spatiotemporal associations were mostly positive (80%), followed by random (15%), and only 5% were negative. Where detected, negative spatiotemporal associations in different communities were due to a few species. The relationship between spatiotemporal association and functional dissimilarity among species was negative, which fulfils the predictions of both environmental filtering and heterospecific attraction. Main conclusions We showed that processes leading to species aggregation (mixture between environmental filtering and heterospecific attraction) seem to dominate assembly rules, and we did not find evidence for competition. Altogether, our hypothesis-testing framework based on joint dynamic species distribution models and functional trait similarity is beneficial in ecological interpretation of species-to-species associations from data covering several decades and biogeographical regions. peerReviewed

SARS- CoV- 2 has been detected both in air and on surfaces, but questions remain about the patient-specific and environmental factors affecting virus transmission. Additionally, more detailed information on viral sampling of the air is needed. This prospective cohort study (N= 56) presents results from 258 air and 252 surface samples from the surroundings of 23 hospitalized and eight home- treated COVID-19 index patients between July 2020 and March 2021 and compares the results between the measured environments and patient factors. Additionally, epidemiological and experimental investigations were performed. The proportions of qRT- PCR- positiveair (10.7% hospital/17.6% homes) and surface samples (8.8%/12.9%) showed statisti-cal similarity in hospital and homes. Significant SARS- CoV- 2 air contamination was observed in a large (655.25 m3) mechanically ventilated (1.67 air changes per hour, 32.4– 421 L/s/patient) patient hall even with only two patients present. All positive air samples were obtained in the absence of aerosol- generating procedures. In four cases, positive environmental samples were detected after the patients had devel-oped a neutralizing IgG response. SARS- CoV- 2 RNA was detected in the following particle sizes: 0.65– 4.7 μm , 7. 0– 12.0 μm, >10μm, and

BackgroundTracing the association between insect cold tolerance and latitudinally and locally varying environmental conditions, as well as key morphological traits and molecular mechanisms, is essential for understanding the processes involved in adaptation. We explored these issues in two closely-related species, Drosophila montana and Drosophila flavomontana, originating from diverse climatic locations across several latitudes on the coastal and mountainous regions of North America. We also investigated the association between sequence variation in one of the key circadian clock genes, vrille, and cold tolerance in both species. Finally, we studied the impact of vrille on fly cold tolerance and cold acclimation ability by silencing it with RNA interference in D. montana.ResultsWe performed a principal component analysis (PCA) on variables representing bioclimatic conditions on the study sites and used latitude as a proxy of photoperiod. PC1 separated the mountainous continental sites from the coastal ones based on temperature variability and precipitation, while PC2 arranged the sites based on summer and annual mean temperatures. Cold tolerance tests showed D. montana to be more cold-tolerant than D. flavomontana and chill coma resistance (CTmin) of this species showed an association with PC2. Chill coma recovery time (CCRT) of both species improved towards northern latitudes, and in D. flavomontana this trait was also associated with PC1. D. flavomontana flies were darkest in the coast and in the northern mountainous populations, but coloration showed no linkage with cold tolerance. Body size decreased towards cold environments in both species, but only within D. montana populations largest flies showed fastest recovery from cold. Finally, both the sequence analysis and RNAi study on vrille suggested this gene to play an essential role in D. montana cold resistance and acclimation, but not in recovery time.ConclusionsOur study demonstrates the complexity of insect cold tolerance and emphasizes the need to trace its association with multiple environmental variables and morphological traits to identify potential agents of natural selection. It also shows that a circadian clock gene vrille is essential both for short- and long-term cold acclimation, potentially elucidating the connection between circadian clock system and cold tolerance.

Species invasions often occur on coasts and estuaries where abiotic conditions vary, e.g. salinity, temperature, runoff etc. Successful establishment and dispersal of non-indigenous species in many such systems are poorly understood, partially since the species tend to show genetic and ecological plasticity at population level towards many abiotic conditions, including salinity tolerance. Plasticity may be driven by shifting expression of heat shock proteins such as Hsp70, which is widely recognized as indicator of physical stress. In this study, we developed a qPCR assay for expression of the hsp70 gene in the invasive round goby (Neogobius melanostomus) and tested the expression response of fish collected from a brackish environment in the western Baltic Sea to three different salinities, 0, 10 and 30. hsp70 expression was highest in fresh water, indicating higher stress, and lower at brackish (ambient condition for the sampled population) and oceanic salinities, suggestive of low stress response to salinities above the population’s current distribution. The highest stress in fresh water was surprising since populations in fresh water exist, e.g. large European rivers and Laurentian Great Lakes. The results have implications to predictions for the species’ plasticity potential and possible range expansion of the species into other salinity regimes.

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During the last few decades, a plethora of sequencing studies provided insight into fungal community composition under various environmental conditions. Still, the mechanisms of species assembly and fungal spread in soil remain largely unknown. While mycelial growth patterns are studied extensively, the abundant formation of asexual spores is often overlooked, though representing a substantial part of the fungal life cycle relevant for survival and dispersal. Here, we explore asexual sporulation (spore abundance, size and shape) in 32 co-occurring soil fungal isolates under varying resource conditions, to answer the question whether resource limitation triggers or inhibits fungal investment into reproduction. We further hypothesized that trade-offs exist in fungal investment towards growth, spore production and size. The results revealed overall increased fungal investment into spore production under resource limitations; however, effect sizes and response types varied strongly among fungal isolates. Such isolate-specific effects were apparent in all measured traits, resulting in unique trait spaces of individual isolates. This comprehensive dataset also elucidated variability in sporulation strategies and trade-offs with fungal growth and reproduction under resource scarcity, as only predicted by theoretical models before. The observed isolate-specific strategies likely underpin mechanisms of co-existence in this diverse group of saprobic soil fungi. peerReviewed

Amphibian larvae typically inhabit relatively shallow freshwater environments, and within these boundaries there is considerable diversity in the structure of the habitats exploited by different species. This diversity in habitat structure is usually taken into account in relation to aspects such as locomotion and feeding, and plays a fundamental role in the classification of tadpoles into ecomorphological guilds. However, its impact in shaping the sensory worlds of different species is rarely addressed, including the optical qualities of each of these types of water bodies and the challenges and limitations that they impose on the repertoire of visual abilities available for a typical vertebrate eye. In this Perspective article, we identify gaps in knowledge on (1) the role of turbidity and light-limited environments in shaping the larval visual system; and (2) the possible behavioral and phenotypic responses of larvae to such environments. We also identify relevant unaddressed study systems paying special attention to phytotelmata, whose small size allows for extensive quantification and manipulation providing a rich and relatively unexplored research model. Furthermore, we generate hypotheses ranging from proximate shifts (i.e., red-shifted spectral sensitivity peaks driven by deviations in chromophore ratios) to ultimate changes in tadpole behavior and phenotype, such as reduced foraging efficiency and the loss of antipredator signaling. Overall, amphibians provide an exciting opportunity to understand adaptations to visually limited environments, and this framework will provide novel experimental considerations and interpretations to kickstart future research based on understanding the evolution and diversity of strategies used to cope with limited visibility.

Here we introduce the Soil BON Foodweb Team, a cross-continental collaborative network that aims to monitor soil animal communities and food webs using consistent methodology at a global scale. Soil animals support vital soil processes via soil structure modification, consumption of dead organic matter, and interactions with microbial and plant communities. Soil animal effects on ecosystem functions have been demonstrated by correlative analyses as well as in laboratory and field experiments, but these studies typically focus on selected animal groups or species at one or few sites with limited variation in environmental conditions. The lack of comprehensive harmonised large-scale soil animal community data including microfauna, mesofauna, and macrofauna, in conjunction with related soil functions, microbial communities, and vegetation, limits our understanding of biological interactions in soil systems and how these interactions affect ecosystem functioning. To provide such data, the Soil BON Foodweb Team invites researchers worldwide to use a common methodology to address six long-term goals: (1) to collect globally representative harmonised data on soil micro-, meso-, and macrofauna communities, (2) to describe key environmental drivers of soil animal communities and food webs, (3) to assess the efficiency of conservation approaches for the protection of soil animal communities, (4) to describe soil food webs and their association with soil functioning globally, (5) to establish a global research network for soil biodiversity monitoring and collaborative projects in related topics, (6) to reinforce local collaboration networks and expertise and support capacity building for soil animal research around the world. In this paper, we describe the vision of the global research network and the common sampling protocol to assess soil animal communities and advocate for the use of standard methodologies across observational and experimental soil animal studies. We will use this protocol to conduct soil animal assessments and reconstruct soil food webs at sites associated with the global soil biodiversity monitoring network, Soil BON, allowing us to assess linkages among soil biodiversity, vegetation, soil physico-chemical properties, climate, and ecosystem functions. In the present paper, we call for researchers especially from countries and ecoregions that remain underrepresented in the majority of soil biodiversity assessments to join us. Together we will be able to provide science-based evidence to support soil biodiversity conservation and functioning of terrestrial ecosystems. Made available in DSpace on 2022-04-05T05:00:35Z (GMT). No. of bitstreams: 1 George-SO-Global.pdf: 4233169 bytes, checksum: 9faad657460c5d69e137289ebd0e4488 (MD5) Previous issue date: 2022

In fish, the lipid resources of the female form a link between the environment and progeny, contributing to the contents of the egg yolk. Variation of the environmental conditions is therefore expected to affect the egg quality via maternal pathways, reflecting the female’s response to the environmental factors before spawning. We investigated the content of lipids and thyroid hormones in the ovary and eggs of the Baltic herring during 1988–2019, when salinity of the Baltic Sea first declined and then stabilized to a lower level, and winters varied between severe and mild. The total lipid resources of spawning females decreased by 40–50% during the study, and the ovarian lipid concentration followed this trend resulting in a decrease of the lipid content of eggs. The concentration of thyroid hormones in the ovary suggested a hormonal response in females to salinity and winter temperature and was observable also in the content of thyroid hormones in the eggs. A change in the egg lipid content took place approximately around 1998 (SE ± 3 years) suggesting that in declining salinity, egg quality was associated with salinity and intrinsic factors in the female, i.e., fecundity and amount of lipids deposited into the ovary. However, during the period of stable salinity, egg quality was mainly limited by the female’s lipid resources. As also the body size of the females decreased over the years, it is suggested that small body size can be a key phenotypic trait to reduce the environmental impact on egg quality in variable environmental conditions. peerReviewed

Environmental filtering and spatial structuring are important ecological processes for the generation and maintenance of biodiversity. However, the relative importance of these ecological drivers for multiple facets of diversity is still poorly understood in highland streams. Here, we examined the responses of three facets of stream macroinvertebrate alpha diversity to local environmental, landscape‐climate and spatial factors in a near‐pristine highland riverine ecosystem. Taxonomic (species richness, Shannon diversity, and evenness), functional (functional richness, evenness, divergence, and Rao's Quadratic entropy), and a proxy of phylogenetic alpha diversity (taxonomic distinctness and variation in taxonomic distinctness) were calculated for macroinvertebrate assemblages in 55 stream sites. Then Pearson correlation coefficient was used to explore congruence of indices within and across the three diversity facets. Finally, multiple linear regression models and variation partitioning were employed to identify the relative importance of different ecological drivers of biodiversity. We found most correlations between the diversity indices within the same facet, and between functional richness and species richness were relatively strong. The two phylogenetic diversity indices were quite independent from taxonomic diversity but correlated with functional diversity indices to some extent. Taxonomic and functional diversity were more strongly determined by environmental variables, while phylogenetic diversity was better explained by spatial factors. In terms of environmental variables, habitat‐scale variables describing habitat complexity and water physical features played the primary role in determining the diversity patterns of all three facets, whereas landscape factors appeared less influential. Our findings indicated that both environmental and spatial factors are important ecological drivers for biodiversity patterns of macroinvertebrates in Tibetan streams, although their relative importance was contingent on different facets of diversity. Such findings verified the complementary roles of taxonomic, functional and phylogenetic diversity, and highlighted the importance of comprehensively considering multiple ecological drivers for different facets of diversity in biodiversity assessment.

We investigated child, family, and environmental factors associated with young children's perceptions of locomotor (LM) and object control (OC) skills. The participants comprised 472 children (6.22 ± 0.63) and their parents. The children were assessed for their perception of motor competence in LM and OC skills (using the pictorial scale of Perceived Movement Skill Competence for young children), and actual motor competence (Test of Gross Motor Development 3rd edition and Körperkoordinationstest Für Kinder). Anthropometrics were calculated using the children's body mass index standard deviation scores. A parent questionnaire included questions about child factors (sex, child's independent walking age, time spent sedentary and outdoors, participation in organized sport activities, and access to electronic devices), family factors (parent educational level, physical activity frequency, and sedentary behavior), and environmental factors (access to sport facilities). Variance analysis sought to identify age-related differences, and a linear regression model examined correlates of children's perception of LM and OC skills. The children's movement skill perceptions were found to be generally high. Four factors explained 5.7% of the variance in perceptions of LM skills and 7.5% of the variance in perceptions of OC skills. Two factors, lower age and higher actual motor competence, explained most of the children's skill perceptions. Access to electronic devices (less) and Body mass index (BMI) (higher) were associated with perceptions of LM skills. Participation in organized sport activities (higher) and parental education (lower) were associated with perceptions of OC skills. When promoting children's physical activity and motor competence, perceptions of motor competence are an important consideration.

Shared socioeconomic pathways (SSPs), developed at global scale, comprise narrative descriptions and quantifications of future world developments that are intended for climate change scenario analysis. However, their extension to national and regional scales can be challenging. Here, we present SSP narratives co-developed with stakeholders for the agriculture and food sector in Finland. These are derived from intensive discussions at a workshop attended by approximately 39 participants offering a range of sectoral perspectives. Using general background descriptions of the SSPs for Europe, facilitated discussions were held in parallel for each of four SSPs reflecting very different contexts for the development of the sector up to 2050 and beyond. Discussions focused on five themes from the perspectives of consumers, producers and policy-makers, included a joint final session and allowed for post-workshop feedback. Results reflect careful sector-based, national-level interpretations of the global SSPs from which we have constructed consensus narratives. Our results also show important critical remarks and minority viewpoints. Interesting features of the Finnish narratives compared to the global SSP narratives include greater emphasis on environmental quality; significant land abandonment in SSPs with reduced livestock production and increased plant-based diets; continued need for some farm subsidies across all SSPs and opportunities for diversifying domestic production under scenarios of restricted trade. Our results can contribute to the development of more detailed national long-term scenarios for food and agriculture that are both relevant for local stakeholders and researchers as well as being consistent with global scenarios being applied internationally.

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According to metacommunity theory (Leibold et al., 2004), the structure of local communities results from the interplay between local factors (e.g., environmental filtering, species interactions) and regional factors (e.g., dispersal rates, landscape configuration). The relative importance of these factors is highly dependent on the organisms’ biological traits, landscape connectivity, and the spatial and temporal scales considered (Heino et al., 2015; Tonkin et al., 2018; Viana and Chase, 2019; Almeida-Gomes et al., 2020; Cañedo-Argüelles et al., 2020; Lansac-Tôha et al., 2021). However, the differences in metacommunity assembly mechanisms found among studies are far from being fully understood. The evaluation of temporal dynamics of metacommunities has only emerged recently (Cañedo-Argüelles et al., 2020; Jabot et al., 2020; Li et al., 2020; Lindholm et al., 2021) and the application of the metacommunity theory in other fields, such as biomonitoring, conservation biology or ecosystem restoration, is yet to be fully explored (Bengtsson, 2010; Heino, 2013; Leibold and Chase, 2018; Chase et al., 2020; Cid et al., 2020; Heino et al., 2021). In this Research Topic, our aim was to invite researchers working in different biogeographic regions and ecological systems (Figure 1) to publish a number of innovative papers on metacommunity spatio-temporal dynamics. We expect to obtain a better understanding of how the factors and processes that structure metacommunities vary in space and time, as well as the implications of such dynamics for biodiversity conservation and ecosystem management.

INTRODUCTION Participation in diverse physical activities has beneficial health effects. However, little is known on how genetic and environmental factors affect this trait. Thus, we examined to what extent these factors explain participation in diverse leisure-time physical activities from late adolescence to adulthood using a twin study design. METHODS The participants were Finnish twins who reported their participation in diverse leisure-time physical activities at ages 17 (n = 5429) and 34 yr (n = 4246). The number of physical activities engaged in was analyzed using applications of structural linear modeling for twin data. RESULTS On average, the total number of physical activities engaged in during leisure time was slightly over three at both ages and in both sexes, with moderate heritability estimates (40%-58%) from adolescence to adulthood. Environmental factors shared by co-twins (e.g., childhood family environment) influenced only in adolescence, being higher for women. Environmental influences unique to each co-twin explained the remaining variances (34%-57%), being higher at age 34 yr. Participation in diverse leisure-time physical activities correlated moderately between ages 17 and 34 yr (men: rtrait = 0.30, 95% confidence interval [CI] = 0.25-0.35; women: rtrait = 0.26, 95% CI = 0.22-0.31). In addition, genetic influences on participation in physical activities correlated moderately between adolescence and adulthood (rA = 0.51, 95% CI = 0.39-0.64, and 0.44, 95% CI = 0.34-0.55, respectively). These common genetic influences explained 93% of the trait correlations found in men and 85% in women. CONCLUSIONS Genetic and unique environmental influences explain a large proportion of variation in the number of leisure-time physical activities. However, the estimates vary by age and sex. Common genetic background mainly explains the continuity of the participation in diverse leisure-time physical activities between adolescence and adulthood.

The spatial extent and incidence of Lyme disease is increasing in the United States, particularly in the Upper Midwest and Northeast. Many previous studies have explored the drivers of its spatial pattern, however, few studies tried to explore the drivers for the changes of Lyme disease. We here compared the spatial patterns of changes of human Lyme cases and incidence in the Northeast and Upper Midwest between 2003–2005 and 2015–2017, and applied two different approaches (i.e., a statistical regularization approach and model averaging) to investigate the climatic and landscape factors affecting the risk change between the two periods. Our results suggested that changes in land-use variables generally showed different relationships with changes of human Lyme risk between the two regions. Changes of variables related to human-use areas showed opposite correlations in two regions. Besides, forest area and forest edge density generally negatively correlated with the change of human Lyme risk. In the context of ongoing habitat change, we consider this study may provide new insight into understanding the responses of human Lyme disease to these changes, and contribute to a better prediction in the future.

Lyme disease, recognized as one of the most important vector-borne diseases worldwide, has been increasing in incidence and spatial extend in United States. In the Northeast and Upper Midwest, Lyme disease is transmitted by Ixodes scapularis. Currently, many studies have been conducted to identify factors influencing Lyme disease risk in the Northeast, however, relatively few studies focused on the Upper Midwest. In this study, we explored and compared the climatic and landscape factors that shape the spatial patterns of human Lyme cases in these two regions, using the generalized linear mixed models. Our results showed that climatic variables generally had opposite correlations with Lyme disease risk, while landscape factors usually had similar effects in these two regions. High precipitation and low temperature were correlated with high Lyme disease risk in the Upper Midwest, while with low Lyme disease risk in the Northeast. In both regions, size and fragmentation related factors of residential area showed positive correlations with Lyme disease risk. Deciduous forests and evergreen forests had opposite effects on Lyme disease risk, but the effects were consistent between two regions. In general, this study provides new insight into understanding the differences of risk factors of human Lyme disease risk in these two regions.

Background Animal skin and gut microbiomes are important components of host fitness. However, the processes that shape the microbiomes of wildlife are poorly understood, particularly with regard to exposure to environmental contaminants. We used 16S rRNA amplicon sequencing to quantify how exposure to radionuclides impacts the skin and gut microbiota of a small mammal, the bank vole Myodes glareolus, inhabiting areas within and outside the Chernobyl Exclusion Zone (CEZ), Ukraine. Results Skin microbiomes of male bank voles were more diverse than females. However, the most pronounced differences in skin microbiomes occurred at a larger spatial scale, with higher alpha diversity in the skin microbiomes of bank voles from areas within the CEZ, whether contaminated by radionuclides or not, than in the skin microbiomes of animals from uncontaminated locations outside the CEZ, near Kyiv. Similarly, irrespective of the level of radionuclide contamination, skin microbiome communities (beta diversity) showed greater similarities within the CEZ, than to the areas near Kyiv. Hence, bank vole skin microbiome communities are structured more by geography than the level of soil radionuclides. This pattern presents a contrast with bank vole gut microbiota, where microbiomes could be strikingly similar among distant (~ 80 km of separation), uncontaminated locations, and where differences in microbiome community structure were associated with the level of radioactivity. We also found that the level of (dis)similarity between the skin and gut microbiome communities from the same individuals was contingent on the potential for exposure to radionuclides. Conclusions Bank vole skin and gut microbiomes have distinct responses to similar environmental cues and thus are structured at different spatial scales. Our study shows how exposure to environmental pollution can affect the relationship between a mammalian host’s skin and gut microbial communities, potentially homogenising the microbiomes in habitats affected by pollution. Electronic supplementary material The online version of this article (10.1186/s40168-018-0595-0) contains supplementary material, which is available to authorized users.

BACKGROUND: Characterizing aggregate genetic risk for alcohol misuse and identifying variants involved in gene-by-environment (G × E) interaction effects has so far been a major challenge. We hypothesized that functional genomic information could be used to enhance detection of polygenic signal underlying alcohol misuse and to prioritize identification of single nucleotide polymorphisms (SNPs) most likely to exhibit G × E effects.METHODS: We examined these questions in the young adult FinnTwin12 sample (n = 1,170). We used genomewide association estimates from an independent sample to derive 2 types of polygenic scores for alcohol problems in FinnTwin12. Genomewide polygenic scores included all SNPs surpassing a designated p-value threshold. DNase polygenic scores were a subset of the genomewide polygenic scores including only variants in DNase I hypersensitive sites (DHSs), which are open chromatin marks likely to index regions with a regulatory function. We conducted parallel analyses using height as a nonpsychiatric model phenotype to evaluate the consistency of effects. For the G × E analyses, we examined whether SNPs in DHSs were overrepresented among SNPs demonstrating significant G × E effects in an interaction between romantic relationship status and intoxication frequency.RESULTS: Contrary to our expectations, we found that DNase polygenic scores were not more strongly predictive of alcohol problems than conventional polygenic scores. However, variants in DNase polygenic scores had per-SNP effects that were up to 1.4 times larger than variants in conventional polygenic scores. This same pattern of effects was also observed in supplementary analyses with height. In G × E models, SNPs in DHSs were modestly overrepresented among SNPs with significant interaction effects for intoxication frequency.CONCLUSIONS: These findings highlight the potential utility of integrating functional genomic annotation information to increase the signal-to-noise ratio in polygenic scores and identify genetic variants that may be most susceptible to environmental modification.

The role of supportive environments on health, wellbeing, and longevity has been widely recognized. However, there is no strong empirical evidence on the association between health literacy (HL) as a particular health-related competence and neighbourhoods. Therefore, the aim of the study was to assess the association between the features of neighbourhoods and the level of HL competencies of young people from three countries (Czech Republic, Poland, Slovakia). Self-reported data from an international sample of 11,521 students aged 13–15 years participating in the Health Behaviour in School-aged Children Study (HBSC) in the year 2018 were included in the analyses. The level of HL shows a strong positive relationship with family wealth, and a significant relationship is maintained in all studied countries. Both social and structural features of neighbourhoods turned out to have an impact on students’ HL. However, HL is most clearly explained by the school environment. This study confirms the school effect on higher levels of HL competences in adolescents. This indicates the need to invest in schools located in less affluent areas to generally improve the level of education, implement modern health education combined with HL, and strengthen the social and health competencies of students.

This paper uses longitudinal survey data linked to administrative registers to examine socioeconomic gradients in health, particularly whether the effects of genetic endowments interact with the socioeconomic resources of the parental household. We find that genetic risk scores contribute to adult health measured by biomarkers. This result is consistent with the findings from genome-wide association studies. Socioeconomic gradients in health differ based on biomarker and resource measures. Family education is negatively related to obesity and the waist-hip ratio, and family income is negatively related to low-density lipoprotein cholesterol and triglyceride levels. Parental resources do not modify the effects of genetic endowment on adult health. However, there is evidence for gene-family income interactions for triglyceride levels, particularly among women. peerReviewed

Environment, physical activity (PA) and motor development are tightly interwoven during childhood. We examined the associations of environmental factors with motor competence (MC) in children. Children (N = 945, 50.1% boys, age = 3–7 years, mean = 5.4 years) from 37 childcare centres in the Southern (n = 17), Central (n = 13) and Northern Finland (n = 7) participated. The environmental factors comprised the geographical location (Southern, Central and Northern Finland) and residential density (metropolitan area, city, rural area and countryside) of the childcare centres’ based on postal codes and the national population density registry. MC was measured using the Test of Gross Motor Development (TGMD)-3, as well as by quantifying time spent outdoors and participation in organised sports via parental questionnaire. It was found that children from the countryside had better MC and spent most time outdoors, while children from the metropolitan area most frequently engaged in organised sports. Gender comparisons revealed that girls outperformed boys in locomotor skills, while boys were better in object control skills, had higher TGMD-3 score and spent more time outdoors. Time spent outdoors and participation in organised sports were associated positively with MC, but not in children from the countryside. In conclusion, higher population density was associated with lower MC and less time spent outdoors. The findings suggest that versatile outdoor environments may support motor development through PA. View Full-Text Keywords: children; motor competence; environment; geographical location; residential density; outdoor time; participation in sports

Understanding the spatial patterns of species distribution and predicting suitable habitats for threatened species are central themes in land use management and planning. In this study, we examined the geographic distribution of threatened mire plant species and identified their national hotspots, i.e. areas with high amounts of suitable habitats for threatened mire plant species. We also determined the main environmental correlates related to the distribution patterns of these species. The specific aims were to: (1) identify the environmental variables that control the distribution of threatened peatland species in a boreal aapa mire zone, Finland; and (2) to identify the richness patterns and hotspots of threatened species. Our results showed that the combination of individual species models offers a useful tool for identifying landscape-scale richness patterns for threatened plant species. The modeling performance was high across the modelled species, and the richness patterns generated by single models coincide with the expected richness pattern based on expert knowledge. The method is therefore a powerful tool for basic biodiversity applications. In cases where reliable models for species occurrences and hotspots can be produced, these models can play a significant role in land-use planning and help managers to meet different conservation challenges.

We investigated child, family, and environmental factors associated with young children’s perceptions of locomotor (LM) and object control (OC) skills. The participants comprised 472 children (6.22 ± 0.63) and their parents. The children were assessed for their perception of motor competence in LM and OC skills (using the pictorial scale of Perceived Movement Skill Competence for young children), and actual motor competence (Test of Gross Motor Development 3rd edition and Körperkoordinationstest Für Kinder). Anthropometrics were calculated using the children’s body mass index standard deviation scores. A parent questionnaire included questions about child factors (sex, child’s independent walking age, time spent sedentary and outdoors, participation in organized sport activities, and access to electronic devices), family factors (parent educational level, physical activity frequency, and sedentary behavior), and environmental factors (access to sport facilities). Variance analysis sought to identify age‐related differences, and a linear regression model examined correlates of children’s perception of LM and OC skills. The children’s movement skill perceptions were found to be generally high. Four factors explained 5.7% of the variance in perceptions of LM skills and 7.5% of the variance in perceptions of OC skills. Two factors, lower age and higher actual motor competence, explained most of the children’s skill perceptions. Access to electronic devices (less) and Body mass index (BMI) (higher) were associated with perceptions of LM skills. Participation in organized sport activities (higher) and parental education (lower) were associated with perceptions of OC skills. When promoting children’s physical activity and motor competence, perceptions of motor competence are an important consideration. peerReviewed

Phenotype and life history traits of an individual are a product of environmental conditions and the genome. Environment can be current or past, which complicates the distinction between environmental and heritable effects on the phenotype in wild animals. We studied genome–environment interactions on phenotype and life history traits by transplanting bank voles (Myodes glareolus) from northern and southern populations, originating from low or high population cycle phases, to common garden conditions in large outdoor enclosures. The first experiment focused on the persistence of body traits in autumn-captured overwintering populations. The second experiment focused on population growth and body traits in spring-captured founder voles and F1 generation. This experiment lasted the breeding season and subsequent winter. We verified phase-dependent differences in body size at capture. In the common environment, adult voles kept their original body size differences both over winter and during the breeding season. In addition, the first generation born in the common environment kept the size distribution of their parent population. The increase phase population maintained a more rapid growth potential, while populations from the decline phase of the cycle grew slower. After winter, the F1 generation of the increasing northern population matured later than the F1 of the southern declining ones. Our results suggest a strong role of heredity or early life conditions, greater than that of current juvenile and adult environmental conditions. Environmental conditions experienced by the parents in their early life can have inter-generational effects that manifest in offspring performance. Electronic supplementary material The online version of this article (10.1007/s00442-019-04410-3) contains supplementary material, which is available to authorized users.

Lapsuusiän kasvuun vaikuttavat sekä perintötekijät että ympäristötekijät. Ensimmäisen puolen vuoden aikana ravitsemus on voimakkaimmin lapsen kasvua säätelevä tekijä. Ravitsemustila vaikuttaa insuliinin kaltaisen kasvutekijä 1:n (IGF-1) pitoisuuksiin, joka osallistuu yhdessä kasvuhormonin kanssa kasvun säätelyyn. Matalan tulotason maissa lasten vajaaravitsemus on yleistä, minkä seurauksena lasten IGF-1-pitoisuudet ovat matalia. IGF-1-pitoisuuksiin vaikuttavat lisäksi ympäristöperäinen suoliston toimintahäiriö, hygieniataso sekä äidin biologiset ominaisuudet. Suurin osa IGF-1-molekyyleistä kulkee verenkierrossa kiinnittyneenä sitojaproteiini 3:een (IGFBP3), joka osallistuu biologisesti aktiivisen IGF-1:n säätelyyn. Tutkimuksessa selvitettiin plasman IGF1- ja IGFBP-3-pitoisuuksien jakaumaa ja siihen vaikuttavia tekijöitä 6, 18 ja 30 kuukauden ikäisillä maaseudulla asuvilla malawilaislapsilla. Plasmanäytteet on kerätty vuosina 2011–2015 osana äitien ja lasten ravitsemustutkimusta. IGF-1- ja IGFBP-3 -pitoisuudet analysoitiin fluoresoiviin väriaineisiin perustuvalla Luminex XMap – tekniikalla. IGF-1-pitoisuuksien keskiarvo 6 kuukauden iässä oli 13,1 ng/ml (n = 519); 18 kuukauden iässä 12,5 ng/ml (n = 605) ja 30 kuukauden iässä 14,5 ng/ml (n = 581). IGFBP-3-pitoisuuksien keskiarvot olivat vastaavasti 2643ng/ml (n = 474); 2676 ng/ml (n = 584) ja 2652 ng/ml (n = 580). 18 ja 30 kuukauden iässä IGF-1- ja IGFBP-3 -pitoisuuksien keskiarvot olivat tytöillä suuremmat kuin pojilla. IGF-1- ja IGFBP-3 -pitoisuudet korreloivat keskenään kaikissa ikäryhmissä. Äidin pituus korreloi lasten IGF-1- ja IGFBP-3 -pitoisuuksiin, mutta äidin painoindeksi, ikä, tulehdusparametrit ja kotitalouden varallisuus korreloivat tuloksiin vain osittain tai eivät lainkaan. Kuivakaudella plasmanäytteiden IGF-1- ja IGFBP-3 -pitoisuudet olivat useimmiten korkeammat kuin sadekaudella. Asuinpaikkakunta, juomaveden lähde ja käytettävissä olevat saniteettitilat vaikuttivat tuloksiin muutamissa vertailluissa ryhmissä. Jotta IGF-1- ja IGFBP-3 -pitoisuuksia voitaisiin hyödyntää sairauksien diagnostiikassa, tulisi käyttää vertailukelpoisesta tutkimusjoukosta saatuja viitearvoja sekä samanlaisia laboratoriomenetelmiä.

1.Parasitic diseases represent one of the greatest challenges for aquaculture worldwide and there is an increasing emphasis on ecological solutions to prevent infections. One proposed solution is enriched rearing, where traditional stimulus‐poor rearing tanks are equipped with different types of structures to increase habitat complexity. Such spatial enrichment is known to increase survival of fish during parasite epidemics, but the underlying mechanisms are still unclear. 2.We studied whether enriched rearing affected infection of an important fish pathogen Flavobacterium columnare in young Atlantic salmon (Salmo salar) and sea‐migrating brown trout (Salmo trutta). First, we used natural bacterial exposures and multiple fish populations in a common garden experiment to address the role of host genetic background in effects of enriched rearing. Second, fish from standard and enriched rearing were experimentally exposed to controlled bacterial doses in standard and enriched environments in a full factorial design to explore the relative roles of rearing background and environment of exposure on survival of fish. 3.Enriched rearing significantly increased survival of fish during the natural bacterial outbreak. This effect was also fairly consistent and observed in eight of the ten fish populations. In the controlled exposure, fish exposed in enriched environment had higher survival regardless of their rearing background, suggesting a stronger impact of the environment on the disease progression. Additionally, the survival in the enriched environment was the highest among the fish of enriched rearing background, supporting the idea of their higher resistance. 4.Synthesis and applications. Our study suggests that the enhanced survival of fish in enriched rearing is a result of a combined effect of the environment and improved fish condition and, to a lesser degree, from host genetic background. This has important implications for when and how environmental enrichment should be applied. Overall, these results indicate that environmental enrichment has the potential to improve survival of fish during parasitic epidemics and thus reduce use of antibiotics in aquaculture. peerReviewed

The early life environment can have profound, long‐lasting effects on an individual's fitness. For example, early life quality might (a) positively associate with fitness (a silver spoon effect), (b) stimulate a predictive adaptive response (by adjusting the phenotype to the quality of the environment to maximize fitness) or (c) be obscured by subsequent plasticity. Potentially, the effects of the early life environment can persist beyond one generation, though the intergenerational plasticity on fitness traits of a subsequent generation is unclear. To study both intra‐ and intergenerational effects of the early life environment, we exposed a first generation of bank voles to two early life stimuli (variation in food and social environment) in a controlled environment. To assess possible intra‐generational effects, the reproductive success of female individuals was investigated by placing them in large outdoor enclosures in two different, ecologically relevant environments (population densities). Resulting offspring were raised in the same population densities where they were conceived and their growth was recorded. When adult, half of the offspring were transferred to opposite population densities to evaluate their winter survival, a crucial fitness trait for bank voles. Our setup allowed us to assess: (a) do early life population density cues elicit an intra‐generational adaptive response, that is a higher reproductive success when the density matches the early life cues and (b) can early life stimuli of one generation elicit an intergenerational adaptive response in their offspring, that is a higher growth and winter survival when the density matches the early life cues of their mother. Our results show that the early life environment directly affects the phenotype and reproductive success of the focal generation, but adaptive responses are only evident in the offspring. Growth of the offspring is maintained only when the environment matches their mother's early life environment. Furthermore, winter survival of offspring also tended to be higher in high population densities if their mothers experienced an competitive early life. These results show that the early life environment can contribute to maintain high fitness in challenging environments, but not necessarily in the generation experiencing the early life cues. peerReviewed

Highlights • We tested patterns of multi-faceted beta diversity across mountain streams. • All three facets of beta diversities increase from the north slope to south slope. • Spatial variables were most important in structuring three facets of beta diversity. • Functional and phylogenetic beta diversity complement to taxonomic beta diversity. • Combining multi-faceted biodiversity is essential for management and conservation. There is a growing recognition that examining patterns of ecological communities and their underlying determinants is not only feasible based on taxonomic data, but also functional and phylogenetic approaches. This is because these additional facets can enhance the understanding of the relative contribution of multiple processes in shaping biodiversity. However, few studies have focused on multifaceted beta diversities in lotic macroinvertebrates, especially when considering driving factors operating at multiple spatial scales. Here, we examined the spatial patterns of multi-faceted (i.e., taxonomic, functional and phylogenetic) beta diversity and their components (i.e., turnover and nestedness) of macroinvertebrates in 50 sites in 10 streams situated in the north and south slope of the Qinling Mountains, the geographical dividing line of Northern and Southern China. We found that the streams draining the north slope showed significantly lower values of beta diversity based on all three facets than the streams draining the south slope. Such north-to-south increases of beta diversity were caused by the distinct climatic and local environmental conditions between the sides of the mountain range. Moreover, spatial variables generally played the most important role in structuring all facets and components of beta diversity, followed by local environmental and climatic variables, whereas catchment variables were less important. Despite the similar results of relative contribution of explanatory variables on each beta diversity facet, the details of community-environment relationships (e.g., important explanatory variables and explanatory power) were distinct among different diversity facets and their components. In conclusion, measuring functional and phylogenetic beta diversity provides complementary information to traditional taxonomic approach. Therefore, an integrative approach embracing multiple facets of diversity can better reveal the mechanisms shaping biodiversity, which is essential in assessing and valuing aquatic ecosystems for biodiversity management and conservation.

Metacommunity ecology highlights the importance of integrating simultaneously environmental filtering and spatial processes, such as mass effects and dispersal limitation, into investigation of community assembly. However, few studies to date have tried to examine mass effects and dispersal limitation as independent ecological mechanisms along with environmental filtering in shaping biological communities in river networks. We examined the relative importance of three factor groups, i.e., environmental variables, within-river spatial factors (indicative of mass effects) and basin identity (referring to dispersal limitation) on a macroinvertebrate metacommunity and nine trait-based deconstructed sub-metacommunities from seven subtropical rivers. We applied redundancy analysis and variance partitioning to reveal the pure and shared effects of the three groups of factors on community variation. Environmental filtering, mass effects and dispersal limitation were all significant mechanisms affecting variation in macroinvertebrate communities, but their relative importance depended on biological traits. Environmental filtering explained more of the variation in the whole metacommunity, tolerant taxa and macroinvertebrate groups with weak dispersal ability (i.e., aquatic dispersal, aerial passive dispersal and large body size). In contrast, mass effects accounted for more variation in the communities of intolerant taxa and macroinvertebrate groups with strong dispersal ability (i.e., aerial active dispersal mode and medium body size). Dispersal limitation was more influential for sub-communities of moderately tolerant taxa and large-sized taxa. Our study highlights that simultaneously accounting for different spatial processes and using a trait-based approach are essential to improve our understanding of community assembly in river networks.

© 2018 Peden et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Objective Drowning claims 7% of the global burden of injury-related deaths. Lifejackets are routinely recommended as a drowning prevention strategy; however, a review of related factors regarding lifejacket wear has not previously been investigated. Methods This systematic review examined literature published from inception to December 2016 in English and German languages. The personal, social, and environmental factors associated with lifejacket wear among adults and children were investigated, a quantitative evaluation of the results undertaken, and gaps in the literature identified. Results Twenty studies, with sample sizes of studies ranging between 20 and 482,331, were identified. Fifty-five percent were cross-sectional studies. All studies were scored IV or V on the Australian National Health and Medical Research Council (NHMRC) grading system indicating mostly descriptive and cross-sectional levels of evidence. Factors associated with increased wear included age (mostly children), gender (mostly female), boat type (non-motorised), boat size (small boats), role modelling (children influenced by adult lifejacket wear), and activity (water-skiing, fishing). Factors not associated or inconsistent with lifejacket wear included education, household income, ethnicity, boating ability, confidence in lifejackets, waterway type, and weather and water conditions. Factors associated with reduced lifejacket wear included adults, males, discomfort, cost and accessibility, consumption of alcohol, and swimming ability. Three studies evaluated the impact of interventions. Conclusion This review identified factors associated with both increased and decreased lifejacket wear. Future research should address the motivational factors associated with individuals’ decisions to wear or not wear lifejackets. This, combined with further research on the evaluation of interventions designed to increase lifejacket wear, will enhance the evidence base to support future drowning prevention interventions.

Understanding ecological and epidemiological factors driving pathogen evolution in contemporary time scales is a major challenge in modern health management. Pathogens that replicate outside the hosts are subject to selection imposed by ambient environmental conditions. Increased nutrient levels could increase pathogen virulence by pre-adapting for efficient use of resources upon contact to a nutrient rich host or by favouring transmission of fast-growing virulent strains. We measured changes in virulence and competition in Flavobacterium columnare, a bacterial pathogen of freshwater fish, under high and low nutrient levels. To test competition between strains in genotype mixtures, we developed a quantitative real-time PCR assay. We found that a virulent strain maintained its virulence and outcompeted less virulent strains independent of the nutrient level and resource renewal rate while a less virulent strain further lost virulence in chemostats under low nutrient level and over long-term serial culture under high nutrient level. Our results suggest that increased outside-host nutrient levels might maintain virulence in less virulent strains and increase their contribution to epidemics in aquaculture. The results highlight a need to further explore the role of resource in the outside-host environment in maintaining strain diversity and driving evolution of virulence among environmentally growing pathogens.

Limited resources force individuals to trade-off between life-history traits. A vast diversity of life-history strategies, which optimally combine life history traits, can be found. Knowledge of the genetic basis of this phenotypic variation is key to understanding evolutionary processes. I approached life-history evolution by estimating quantitative genetic parameters for a set of life-history traits in the bank vole (Myodes glareolus). The work is based on a laboratory-kept colony subjected to two-way selection for litter size (High- (H) and Low- (L) lines). Costs of the created reproductive strategies were observed in natural conditions. Selection increased the difference in litter size between lines, even though the response was asymmetric. The difference persisted in outdoor enclosures. A life-history trade-off between offspring number and offspring size was explained by environmental correlations as associated genetic correlations were even positive. Lines did not diverge in offspring size. In the enclosures maternal body mass had greater effect on pup survival in the L-line. Litter and maternal environment explained most of the phenotypic variation in pup body mass during the nursing period, while direct genetic variation emerged later, implicating selection on early size in the bank vole. Male and female metabolic rate did not seem to share genetic background; the first lacking additive genetic variation and the latter being bound to fecundity by genetic correlation close to one. Testosterone, a principle determinant of male reproductive success in the bank vole, was contrasted with humoral immune system in the both sexes. In general, with the exception of metabolism, the estimated genetic parameters did not set absolute constraints for life-history evolution. However, dimensionality of the additive genetic co(variance) matrix constrains evolution to act along certain trait combinations. In the future, research should strive to find genetic mechanisms, which, through the endocrine system, produces phenotypic co(variation) in different life-history traits.

Raskaudenaikainen malaria aiheuttaa odottaville äideille anemiaa, ja vastasyntyneelle pientä syntymäpainoa ja ennenaikaisuutta. Saharan eteläpuolisessa Afrikassa raskaana olevien naisten malaria on usein oireeton, ja parasiittien määrä perifeerisessä veressä on pieni. Perinteisellä mikroskopialla raskaana olevien malariainfektioita jää huomaamatta. PCR-tekniikalla on mahdollista havaita pienen parasiittitiheyden submikroskooppiset infektiot. Tässä tutkimuksessa selvitettiin ympäristötekijöiden vaikutusta submikroskooppisen malarian esiintyvyyteen raskaana olevilla naisilla Malawissa. Tutkimuksessa käytetty aineisto on kerätty vuosien 2003 ja 2006 välillä Lungwenan kylässä Malawissa. Terveyskeskuksen äitiysklinikalta rekrytoiduilta raskaana olevilta naisilta otettiin tutkimuksen alussa verinäyte, josta tunnistettiin P. falciparumin laktaattidehydrogenaasi-geeniä real-time PCR -menetelmällä. Malarian esiintyvyyttä verrattiin ympäristötekijöihin, joita selvitettiin tutkimuksen alussa täytetyn kyselykaavakkeen avulla. Submikroskooppisen malarian esiintyvyys oli 40,6 %. Hyttysverkon omisti 73,5 % raskaana olevista naisista ja heistä 82,4 % oli edellisenä yönä nukkunut sen alla. Hyttysverkon omistaminen alensi merkitsevästi malariainfektion riskiä (AOR = 0.6, 95 % CI 0.5-0.8, p < 0.001), sen sijaan hyttysverkon käytöllä ei ollut merkitsevää yhteyttä malariainfektioon. Muista ympäristötekijöistä merkitsevästi malariainfektion riskiä vähensi hyttysverkon käsitteleminen hyttysmyrkyllä, asuintalon ikkunat, suurempi henkilömäärä taloudessa ja kuiva vuodenaika. Lisäksi malarian riskiä suurensi, jos juomaveden lähteenä oli suojaamaton kaivo, järvi, lampi tai joki. Tärkeimpänä malarialta suojaavana tekijänä raskaana olevilla naisilla nousi esiin hyttysverkot ja niiden jatkuva käyttö. Yleisesti asuinolojen parantaminen vähentäisi riskiä sairastua malariaan. Köyhyyden vastaiset keinot vaikuttanevat suotuisasti myös raskaudenaikaisen malarian estämiseen.