Understanding land use volatility and agglomeration in northern Southeast Asia.

Land use change has generally been considered a cause and consequence of environmental change. Here, we interpreted the land cover in northern Southeast Asia (including parts of Myanmar, Thailand, Laos, Vietnam and China) year by year from 2000 to 2018 with the Google Earth Engine (GEE) platform. The results show that the areas of old growth forest, young growth forest and annual crops have changed dramatically in the study area. The average frequency of land use change was determined to be 5.4 times (that is, the land use changed every 3.4 years) by comparing the land use types in each year throughout the entire study period, and the frequency of land use change showed a significant agglomeration effect. In addition, there was a substantial difference between the land use change determined with an annual approach and that determined with the commonly used time-stage approach; time-stage land use change studies may overlook gradual change processes in land use change, which highlights the necessary of determining a suitable time period for studying land use change at the local scale. The results show that understanding land use volatility and agglomeration has become important to deepen the understanding of land use change and to help formulate land use policy.

Who is afraid of ticks and tick-borne diseases? Results from a cross-sectional survey in Scandinavia.

BACKGROUND: In Scandinavia, the distribution of ticks is expanding and tick-borne diseases constitute growing health risks. While the probability of getting a tick-borne disease after a tick bite is low, the health impacts can be large. This, as well as other characteristics of these diseases make tick-related risks difficult for laypeople to assess and perceived risk may differ substantially from actual risk. Understanding risk perceptions is important since it is the perceived risk, rather than actual risk, that determine behaviour and even more so for new and emerging risks. The aim of this study is to investigate knowledge and risk perceptions related to tick bites and the tick-borne diseases Lyme borreliosis (LB) and tick-borne encephalitis (TBE). By analysing risk perceptions and knowledge, the study helps inform the development of public health strategies in response to the increasing incidence of these diseases in Scandinavia. METHODS: Two thousand, six hundred sixty-eight respondents in Denmark, Norway and Sweden answered an online questionnaire with 48 questions, including 7 questions on risk perceptions and 9 knowledge questions. Chi-squared tests were used to analyse statistical differences between country sub-samples, gender and age groups. A multivariate regression model was used to analyse factors associated with risk perceptions. RESULTS: Risk perceptions were on average high in comparison with scientific estimates, with respondents grossly overrating the probability of contracting LB or TBE if bitten by a tick. Also, the average perceived seriousness of a single tick bite and of getting LB or TBE was high. Knowledge on the other hand was low, especially among men and the youngest age group (18-29 years). Higher levels of knowledge about tick-borne diseases were associated with lower perceived seriousness of tick bites and LB and higher perceived seriousness of TBE. Also, having been diagnosed with LB was negatively associated with the perceived seriousness of LB. CONCLUSIONS: Our results indicate that informing about ticks and tick-borne diseases would be a relevant public health strategy as it could make risk perceptions better aligned with actual risk. Should the TBE virus spread further in Denmark and Norway, increasing knowledge about TBE vaccination would be especially important.

Protective practices against tick bites in Denmark, Norway and Sweden: a questionnaire-based study.

BACKGROUND: Tick-borne infections are of emerging and increasing concern in the Scandinavian countries Denmark, Norway and Sweden. Only few studies have investigated protective practices against tick bites in the general population. The aim of this multi-country study was to assess the use of protective practices and the perception of the efficacy of them. METHODS: We surveyed the extent of using protective practices against tick bites, using the same questionnaire in three local languages. In addition, we surveyed perceptions of how good a protection the different practices provide. Altogether 783 individuals from Denmark, 789 from Norway and 1096 from Sweden participated in the study by completing an extensive online questionnaire in October 2016. RESULTS: Altogether 1011 respondents (37.9%) reported using at least three different protective practices either often or always when in areas where there are ticks, while 522 (19.6%) reported using none. Female gender was among the factors identified as positively associated with using several of the specific practices often or always when in areas where there are ticks. The gender-difference in extent of using protective practices against tick bites was particularly pronounced in Sweden. Based on a multivariable logistic regression model, being female, being from Sweden, and having experienced one or more tick bites were positively associated with using at least three different protective practices against tick bites either often or always when in areas where there are ticks (odds ratios 1.90, 1.87 and 1.88, respectively). CONCLUSIONS: The results of our study, especially the observed differences by country and by gender, can be useful in targeting future information to the public. In particular, our results suggest that men across all ages should be considered a specific target group for this information.

Incidence and seasonality of respiratory syncytial virus hospitalisations in young children in Denmark, 2010 to 2015.

For future decisions on respiratory syncytial virus (RSV)-vaccination strategies and implementation into national immunisation-programmes, we used national registry data (hospitalisation, microbiology and vital statistics) to determine the age-specific incidence and direct medical costs of annual RSV-associated admissions in children < 5 years-old for the period of 2010-2015. We identified ca 2,500 RSV-associated hospitalisations annually amounting to total direct medical-costs of ca EUR 4.1 million per year. The incidence of RSV-associated hospitalisations peaked in infants 1-2 months of age followed by infants 2-3 months of age, and infants < 1 month of age, respectively. Infant boys were at higher risk of severe RSV infection as compared to infant girls: male-to-female ratio peaked with 1.4 at four months of age and gradually levelled out with increasing age to 1.0 at 4 years of age. Five RSV-associated deaths were identified. Our findings demonstrate that in a western country as Denmark, RSV constitutes a considerable burden on childhood health. Furthermore, the best approach to reduce the high incidence of RSV-associated hospitalisations in young infants < 3 months of age may be maternal vaccination due to general challenges in achieving sufficient and protective immune responses in young infants.

Dengue outbreaks in high-income area, Kaohsiung City, Taiwan, 2003-2009.

Kaohsiung City, a modern metropolis of 1.5 million persons, has been the focus of dengue virus activity in Taiwan for several decades. The aim of this study was to provide a temporal and spatial description of dengue virus epidemiology in Kaohsiung City by using data for all laboratory-confirmed dengue cases during 2003-2009. We investigated age- and sex-dependent incidence rates and the spatiotemporal patterns of all cases confirmed through passive or active surveillance. Elderly persons were at particularly high risk for dengue virus-related sickness and death. Of all confirmed cases, ≈75% were detected through passive surveillance activities; case-patients detected through active surveillance included immediate family members, neighbors, and colleagues of confirmed case-patients. Changing patterns of case clustering could be due to the effect of unmeasured environmental and demographic factors.

Human papillomavirus transmission and cost-effectiveness of introducing quadrivalent HPV vaccination in Denmark.

OBJECTIVES: The objective of this study was to simulate human papillomavirus (HPV) infection in a heterosexual population and subsequently analyze the incremental costs and effects of introducing a vaccination program against HPV types 6, 11, 16, and 18 in Denmark compared with screening alone. METHODS: The analysis was performed in two phases. First, an agent-based transmission model was developed that described the HPV transmission without and with HPV vaccination. Second, an analysis of the incremental costs and effects was performed. The results of prevalence estimates of HPV, genital warts, cervical intraepithelial neoplasia (CIN1-3), and cervical cancer in the model simulations before and after introduction of HPV vaccination were extrapolated to the Danish population figures. Incremental costs and effects were then estimated. Future costs and effects were discounted. RESULTS: Cost-effectiveness ratios for annual vaccination of 12-year-old girls, with a vaccination rate of 70 percent without a catch-up program, were estimated at approximately 1,917 euro per quality-adjusted life-year (QALY, 3 percent discount rate) and 10,846 euro/QALY (5 percent discount rate), given a 62-year time horizon. CONCLUSIONS: A vaccination program would incur extra vaccination costs but would save treatment costs and improve both quality of life and survival.

Spatial tick bite exposure and associated risk factors in Scandinavia.

Tick-borne diseases are emerging and re-emerging threats causing public health concerns in Europe and North America. Prevention and control requires understanding of human exposure and behaviour. The aim was to measure exposure to tick bites across Scandinavia, its spatial distribution and the associated risk factors. Methods We sent a web-based survey to a randomly chosen population and analysed answers by Principal Component Analysis and Chi-Square. Individual responses were aggregated at the municipality level to assess the spatial distribution of bites. Results Nearly 60% of adults reported bites at low levels (1-5 bites); however, the majority were not in their resident municipality. We found two spatial profiles: In their home municipalities, people were most often bitten in less, but not the least, urbanized areas. When visiting other municipalities, people were most frequently bitten in peri-urban areas. Running/walking in the forest, gardening, and paddling/rowing were activities most strongly associated with bites. Conclusion Tick bites affect the entire Scandinavian population, with a higher risk in Sweden compared to Denmark and Norway. The frequency of observation of ticks in the environment or on pets might be used as a proxy for the actual risk of exposure to tick bites. Our results indicates that urban-dwelling outdoor enthusiasts and inhabitants of rural areas must be equally targeted for prevention campaigns.

Laboratory Diagnostics of Rickettsia Infections in Denmark 2008-2015.

Rickettsiosis is a vector-borne disease caused by bacterial species in the genus Rickettsia. Ticks in Scandinavia are reported to be infected with Rickettsia, yet only a few Scandinavian human cases are described, and rickettsiosis is poorly understood. The aim of this study was to determine the prevalence of rickettsiosis in Denmark based on laboratory findings. We found that in the Danish individuals who tested positive for Rickettsia by serology, the majority (86%; 484/561) of the infections belonged to the spotted fever group. In contrast, we could confirm 13 of 41 (32%) PCR-positive individuals by sequencing and identified all of these as R. africae, indicating infections after travel exposure. These 13 samples were collected from wound/skin material. In Denmark, approximately 85 individuals test positive for Rickettsia spp. annually, giving an estimated 26% (561/2147) annual prevalence among those suspected of rickettsiosis after tick bites. However, without clinical data and a history of travel exposure, a true estimation of rickettsiosis acquired endemically by tick bites cannot be made. Therefore, we recommend that both clinical data and specific travel exposure be included in a surveillance system of Rickettsia infections.

Campylobacter infections expected to increase due to climate change in Northern Europe.

Global climate change is predicted to alter precipitation and temperature patterns across the world, affecting a range of infectious diseases and particularly foodborne infections such as Campylobacter. In this study, we used national surveillance data to analyse the relationship between climate and campylobacteriosis in Denmark, Finland, Norway and Sweden and estimate the impact of climate changes on future disease patterns. We show that Campylobacter incidences are linked to increases in temperature and especially precipitation in the week before illness, suggesting a non-food transmission route. These four countries may experience a doubling of Campylobacter cases by the end of the 2080s, corresponding to around 6,000 excess cases per year caused only by climate changes. Considering the strong worldwide burden of campylobacteriosis, it is important to assess local and regional impacts of climate change in order to initiate timely public health management and adaptation strategies.

Forest management in southern China generates short term extensive carbon sequestration.

Land use policies have turned southern China into one of the most intensively managed forest regions in the world, with actions maximizing forest cover on soils with marginal agricultural potential while concurrently increasing livelihoods and mitigating climate change. Based on satellite observations, here we show that diverse land use changes in southern China have increased standing aboveground carbon stocks by 0.11 ± 0.05 Pg C y-1 during 2002-2017. Most of this regional carbon sink was contributed by newly established forests (32%), while forests already existing contributed 24%. Forest growth in harvested forest areas contributed 16% and non-forest areas contributed 28% to the carbon sink, while timber harvest was tripled. Soil moisture declined significantly in 8% of the area. We demonstrate that land management in southern China has been removing an amount of carbon equivalent to 33% of regional fossil CO2 emissions during the last 6 years, but forest growth saturation, land competition for food production and soil-water depletion challenge the longevity of this carbon sink service.

Spatio-temporal cluster analysis of the incidence of Campylobacter cases and patients with general diarrhea in a Danish county, 1995-2004.

Campylobacter infections are the main cause of bacterial gastroenteritis in Denmark. While primarily foodborne, Campylobacter infections are also to some degree acquired through other sources which may include contact with animals or the environment, locally contaminated drinking water and more. We analyzed Campylobacter cases for clustering in space and time for the large Danish island of Funen in the period 1995-2003, under the assumption that infections caused by 'environmental' factors may show persistent clustering while foodborne infections will occur randomly in space. Input data were geo-coded datasets of the addresses of laboratory-confirmed Campylobacter cases and of the background population of Funen County. The dataset had a spatial extent of 4.900 km2. Data were aggregated into units of analysis (so-called features) of 5 km by 5 km times 1 year, and the Campylobacter incidence calculated. We used a modified form of local Moran's I to test if features with similar incidence rates occurred next to each other in space and time, and compared the observed clusters with simulated clusters. Because clusters may be caused by a high tendency among local GPs to submit stool samples, we also analyzed a dataset of all submitted stool samples for comparison. The results showed a significant persisting clustering of Campylobacter incidence rates in the Western part of Funen. Results were visualized using the Netlogo software. The underlying causes of the observed clustering are not known and will require further examination, but may be partially explained by an increased rate of stool samples submissions by physicians in the area. We hope, by this approach, to have developed a tool which will allow for analyses of geographical clusters which may in turn form a basis for further epidemiological examinations to cast light on the sources of infection.

Population-level impact, herd immunity, and elimination after human papillomavirus vaccination: a systematic review and meta-analysis of predictions from transmission-dynamic models.

BACKGROUND: Modelling studies have been widely used to inform human papillomavirus (HPV) vaccination policy decisions; however, many models exist and it is not known whether they produce consistent predictions of population-level effectiveness and herd effects. We did a systematic review and meta-analysis of model predictions of the long-term population-level effectiveness of vaccination against HPV 16, 18, 6, and 11 infection in women and men, to examine the variability in predicted herd effects, incremental benefit of vaccinating boys, and potential for HPV-vaccine-type elimination. METHODS: We searched MEDLINE and Embase for transmission-dynamic modelling studies published between Jan 1, 2009, and April 28, 2015, that predicted the population-level impact of vaccination on HPV 6, 11, 16, and 18 infections in high-income countries. We contacted authors to determine whether they were willing to produce new predictions for standardised scenarios. Strategies investigated were girls-only vaccination and girls and boys vaccination at age 12 years. Base-case vaccine characteristics were 100% efficacy and lifetime protection. We did sensitivity analyses by varying vaccination coverage, vaccine efficacy, and duration of protection. For all scenarios we pooled model predictions of relative reductions in HPV prevalence (RRprev) over time after vaccination and summarised results using the median and 10th and 90th percentiles (80% uncertainty intervals [UI]). FINDINGS: 16 of 19 eligible models from ten high-income countries provided predictions. Under base-case assumptions, 40% vaccination coverage and girls-only vaccination, the RRprev of HPV 16 among women and men was 0·53 (80% UI 0·46-0·68) and 0·36 (0·28-0·61), respectively, after 70 years. With 80% girls-only vaccination coverage, the RRprev of HPV 16 among women and men was 0·93 (0·90-1·00) and 0·83 (0·75-1·00), respectively. Vaccinating boys in addition to girls increased the RRprev of HPV 16 among women and men by 0·18 (0·13-0·32) and 0·35 (0·27-0·39) for 40% coverage, and 0·07 (0·00-0·10) and 0·16 (0·01-0·25) for 80% coverage, respectively. The RRprev were greater for HPV 6, 11, and 18 than for HPV 16 for all scenarios investigated. Finally at 80% coverage, most models predicted that girls and boys vaccination would eliminate HPV 6, 11, 16, and 18, with a median RRprev of 1·00 for women and men for all four HPV types. Variability in pooled findings was low, but increased with lower vaccination coverage and shorter vaccine protection (from lifetime to 20 years). INTERPRETATION: Although HPV models differ in structure, data used for calibration, and settings, our population-level predictions were generally concordant and suggest that strong herd effects are expected from vaccinating girls only, even with coverage as low as 20%. Elimination of HPV 16, 18, 6, and 11 is possible if 80% coverage in girls and boys is reached and if high vaccine efficacy is maintained over time. FUNDING: Canadian Institutes of Health Research.

Greenlandic sheep farming controlled by vegetation response today and at the end of the 21st century.

The spatial heterogeneity of vegetation greenness and potential aboveground biomass production for sheep farming has been assessed for Southwest Greenland. A Multi-Criteria Evaluation (MCE) model was set up to identify biophysical constraints on the present spatial distribution of farms and fields based on all existing sheep farms in a detailed study area. Time-integrated NDVI (TI-NDVI) from MODIS and observed temperatures (2000-2012) have been combined with a downscaled regional climate model (HIRHAM5) in order to establish a spatio-temporal model for future TI-NDVI, thus forecasting the dry biomass production available for sheep farming in steps of decades for the next 85 years. The model has been validated against observed biomass production and the present distribution of fields. Future biomass production is used to discuss the expansion of current farms and to identify new suitable areas for sheep farming. Interestingly, new suitable areas are located where sheep farms were situated during the Norse era more than 1000 years ago; areas which have been abandoned for the past 500 years. The study highlights the potential of establishing new areas for sheep farming in Arctic Greenland, where current and future climate changes are markedly amplified compared to global trends. However, for the study area the MCE model clearly indicates that the potential of expansion relies on contemporary infrastructural development.

A conceptual framework for analysing and measuring land-use intensity.

Large knowledge gaps currently exist that limit our ability to understand and characterise dynamics and patterns of land-use intensity: in particular, a comprehensive conceptual framework and a system of measurement are lacking. This situation hampers the development of a sound understanding of the mechanisms, determinants, and constraints underlying changes in land-use intensity. On the basis of a review of approaches for studying land-use intensity, we propose a conceptual framework to quantify and analyse land-use intensity. This framework integrates three dimensions: (a) input intensity, (b) output intensity, and (c) the associated system-level impacts of land-based production (e.g. changes in carbon storage or biodiversity). The systematic development of indicators across these dimensions would provide opportunities for the systematic analyses of the trade-offs, synergies and opportunity costs of land-use intensification strategies.

Challenges and opportunities in mapping land use intensity globally.

Future increases in land-based production will need to focus more on sustainably intensifying existing production systems. Unfortunately, our understanding of the global patterns of land use intensity is weak, partly because land use intensity is a complex, multidimensional term, and partly because we lack appropriate datasets to assess land use intensity across broad geographic extents. Here, we review the state of the art regarding approaches for mapping land use intensity and provide a comprehensive overview of available global-scale datasets on land use intensity. We also outline major challenges and opportunities for mapping land use intensity for cropland, grazing, and forestry systems, and identify key issues for future research.

Cost-effectiveness of human papillomavirus vaccine in reducing the risk of cervical cancer in Ireland due to HPV types 16 and 18 using a transmission dynamic model.

We evaluated the cost-effectiveness of combining a cervical cancer screening programme with a national HPV vaccination programme compared to a screening programme alone to prevent cervical dysplasia and cervical cancer related to HPV types 16 and 18 in the Irish healthcare setting. The incremental cost effectiveness of vaccination strategies for 12-year-old females (base-case) and 12-26-year-old catch-up vaccination strategies were examined. The base-case incremental cost-effectiveness ratio was euro17,383/LYG. Using a probabilistic sensitivity analysis about the base-case, the 95% CI for cost per LYG was (euro3400 to euro38,400). This suggests that vaccination against HPV types 16 and 18 would be cost-effective from the perspective of the Irish healthcare payer.