31 research outputs found
Studies on Control of Fowl Cholera
Fowl cholera is a contagious disease of domestic fowls and many wild birds caused by a bacterium, Pasteurella multocida. It is one of the oldest known infectious diseases of poultry. In South Dakota, fowl cholera has been a poultry disease of major importance for many years. Experimental work was undertaken at this station in 1944 to study fowl cholera as related to this area and to investigate the development or improvement of control measures to more effectively prevent losses from this disease. This bulletin is a report of that work
Global, regional, and national age-sex-specific mortality and life expectancy, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
BACKGROUND:
Assessments of age-specific mortality and life expectancy have been done by the UN Population Division, Department of Economics and Social Affairs (UNPOP), the United States Census Bureau, WHO, and as part of previous iterations of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD). Previous iterations of the GBD used population estimates from UNPOP, which were not derived in a way that was internally consistent with the estimates of the numbers of deaths in the GBD. The present iteration of the GBD, GBD 2017, improves on previous assessments and provides timely estimates of the mortality experience of populations globally.
METHODS:
The GBD uses all available data to produce estimates of mortality rates between 1950 and 2017 for 23 age groups, both sexes, and 918 locations, including 195 countries and territories and subnational locations for 16 countries. Data used include vital registration systems, sample registration systems, household surveys (complete birth histories, summary birth histories, sibling histories), censuses (summary birth histories, household deaths), and Demographic Surveillance Sites. In total, this analysis used 8259 data sources. Estimates of the probability of death between birth and the age of 5 years and between ages 15 and 60 years are generated and then input into a model life table system to produce complete life tables for all locations and years. Fatal discontinuities and mortality due to HIV/AIDS are analysed separately and then incorporated into the estimation. We analyse the relationship between age-specific mortality and development status using the Socio-demographic Index, a composite measure based on fertility under the age of 25 years, education, and income. There are four main methodological improvements in GBD 2017 compared with GBD 2016: 622 additional data sources have been incorporated; new estimates of population, generated by the GBD study, are used; statistical methods used in different components of the analysis have been further standardised and improved; and the analysis has been extended backwards in time by two decades to start in 1950.
FINDINGS:
Globally, 18·7% (95% uncertainty interval 18·4–19·0) of deaths were registered in 1950 and that proportion has been steadily increasing since, with 58·8% (58·2–59·3) of all deaths being registered in 2015. At the global level, between 1950 and 2017, life expectancy increased from 48·1 years (46·5–49·6) to 70·5 years (70·1–70·8) for men and from 52·9 years (51·7–54·0) to 75·6 years (75·3–75·9) for women. Despite this overall progress, there remains substantial variation in life expectancy at birth in 2017, which ranges from 49·1 years (46·5–51·7) for men in the Central African Republic to 87·6 years (86·9–88·1) among women in Singapore. The greatest progress across age groups was for children younger than 5 years; under-5 mortality dropped from 216·0 deaths (196·3–238·1) per 1000 livebirths in 1950 to 38·9 deaths (35·6–42·83) per 1000 livebirths in 2017, with huge reductions across countries. Nevertheless, there were still 5·4 million (5·2–5·6) deaths among children younger than 5 years in the world in 2017. Progress has been less pronounced and more variable for adults, especially for adult males, who had stagnant or increasing mortality rates in several countries. The gap between male and female life expectancy between 1950 and 2017, while relatively stable at the global level, shows distinctive patterns across super-regions and has consistently been the largest in central Europe, eastern Europe, and central Asia, and smallest in south Asia. Performance was also variable across countries and time in observed mortality rates compared with those expected on the basis of development.
INTERPRETATION:
This analysis of age-sex-specific mortality shows that there are remarkably complex patterns in population mortality across countries. The findings of this study highlight global successes, such as the large decline in under-5 mortality, which reflects significant local, national, and global commitment and investment over several decades. However, they also bring attention to mortality patterns that are a cause for concern, particularly among adult men and, to a lesser extent, women, whose mortality rates have stagnated in many countries over the time period of this study, and in some cases are increasing
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990�2015: a systematic analysis for the Global Burden of Disease Study 2015
Background The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors�the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25 over the same period. All risks jointly evaluated in 2015 accounted for 57·8 (95 CI 56·6�58·8) of global deaths and 41·2 (39·8�42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million 192·7 million to 231·1 million global DALYs), smoking (148·6 million 134·2 million to 163·1 million), high fasting plasma glucose (143·1 million 125·1 million to 163·5 million), high BMI (120·1 million 83·8 million to 158·4 million), childhood undernutrition (113·3 million 103·9 million to 123·4 million), ambient particulate matter (103·1 million 90·8 million to 115·1 million), high total cholesterol (88·7 million 74·6 million to 105·7 million), household air pollution (85·6 million 66·7 million to 106·1 million), alcohol use (85·0 million 77·2 million to 93·0 million), and diets high in sodium (83·0 million 49·3 million to 127·5 million). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation. © 2016 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY licens
Studies on the presence and persistence of Pasteurella multocida serovars and genotypes in fowl cholera outbreaks
Pasteurella multocida was isolated from poultry on six farms (one free-range duck farm, one free-range turkey farm, one conventional enclosed turkey farm, and three free-range layer farms) suffering fowl cholera outbreaks. In addition, historical isolates from previous outbreaks were available for the conventional turkey farm and the three free-range layer farms. The isolates were serotyped using the Heddleston scheme and genotyped using multi-locus sequencing typing. In the current outbreaks, two of the farms had two different sequence types (STs) of P. multocida in the investigated outbreak (the free-range turkey farm and one of the free-range layer farms). The remaining four farms had one ST within the investigated outbreak. In looking at the historical isolates, two of the four farms had multiple genotypes involved. On the four farms with historical isolates from previous outbreaks, at least one new genotype was present in the investigated outbreak as compared with the historical isolates. On one layer farm, one genotype persisted over a 10-year period. Serotyping revealed the presence of multiple serovars in the current and historical outbreaks, with serovars sometimes changing over time. This study has shown that several STs of P. multocida can be present during some outbreaks of fowl cholera, although other outbreaks involve a single ST. Also, the STs present on a property suffering repeated fowl cholera can both persist and change over time. © 201
Micrometeorology and flux partitioning between forest understorey and overstorey: a synthesis based on FLUXNET data
International audienceBecause most forests are multi-specific and vertically heterogeneous, understanding the functioning of such complex ecosystems remains a challenge for quantifying and modeling the fluxes of CO2 between the atmosphere and the vegetation at regional scale. In particular, there is lack of knowledge concerning flux partitioning between overstorey and understorey of forests across different climates and forest types. The main objective of this study is to compare the micrometeorology and the fluxes of CO2, water and sensible heat measured by the eddy-covariance method above and below the main canopy of different forests. The eight study sites are part of the Fluxnet network, and range through various climates and structural types. Across these different biomes, the leaf area index (LAI) of the overstorey is the main factor influencing flux footprint and turbulent mixing below the canopy, and flux partitioning between overstorey and understorey. Wind direction and rates of turbulent mixing generally differ between the two levels for close canopies and low wind speed in the boundary layer. Forcing of understorey turbulent mixing by overstorey conditions is stronger in case of low overstorey LAI, while trunk space flow tends to decouple from that in the boundary layer in closed canopies. Vertical light extinction is positively correlated with overstorey LAI. During the day, efflux of CO2 from the understorey is positively related to soil temperature. Uptake of CO2 by the understorey only occurs if a significant amount of light penetrates through the overstorey and reaches a significant amount of understorey leaf area. During the night, the probability that CO2 emitted from the soil reach the top of the canopy is negatively correlated with overstorey LAI. These results will help developing sound ecosystem modeling schemes for quantifying carbon budgets at regional scales, taking into account the wide variety of mixed and vertically complex forest canopies
Micrometeorology and flux partitioning between forest understorey and overstorey: a synthesis based on FLUXNET data
International audienceBecause most forests are multi-specific and vertically heterogeneous, understanding the functioning of such complex ecosystems remains a challenge for quantifying and modeling the fluxes of CO2 between the atmosphere and the vegetation at regional scale. In particular, there is lack of knowledge concerning flux partitioning between overstorey and understorey of forests across different climates and forest types. The main objective of this study is to compare the micrometeorology and the fluxes of CO2, water and sensible heat measured by the eddy-covariance method above and below the main canopy of different forests. The eight study sites are part of the Fluxnet network, and range through various climates and structural types. Across these different biomes, the leaf area index (LAI) of the overstorey is the main factor influencing flux footprint and turbulent mixing below the canopy, and flux partitioning between overstorey and understorey. Wind direction and rates of turbulent mixing generally differ between the two levels for close canopies and low wind speed in the boundary layer. Forcing of understorey turbulent mixing by overstorey conditions is stronger in case of low overstorey LAI, while trunk space flow tends to decouple from that in the boundary layer in closed canopies. Vertical light extinction is positively correlated with overstorey LAI. During the day, efflux of CO2 from the understorey is positively related to soil temperature. Uptake of CO2 by the understorey only occurs if a significant amount of light penetrates through the overstorey and reaches a significant amount of understorey leaf area. During the night, the probability that CO2 emitted from the soil reach the top of the canopy is negatively correlated with overstorey LAI. These results will help developing sound ecosystem modeling schemes for quantifying carbon budgets at regional scales, taking into account the wide variety of mixed and vertically complex forest canopies
Partitioning forest carbon fluxes with overstory and understory edd-covariance measurements: a synthesis based on FLUXNET data
International audienc
Partitioning forest carbon fluxes with overstory and understory edd-covariance measurements: a synthesis based on FLUXNET data
International audienc