Controlled exposure as a management tool for Glasser's disease.

In this study, nasal swabs taken from multiparous sows at weaning time or from sick pigs displaying symptoms of Glasser's disease from farms in Australia [date not given] were cultured and analysed by polymerase chain reaction (PCR). Within each genotype detected on a farm, representative isolates were serotyped by gel diffusion (GD) testing or indirect haemagglutination (IHA) test. Isolates which did not react in any of the tests were regarded as non-typable and were termed serovar NT. Serovars 1, 5, 12, 13 and 14 were classified as highly pathogenic; serovars 2, 4 and 15 being moderately pathogenic; serovar 8 being slightly pathogenic and serovars 3, 6, 7, 9 and 11 being non-pathogenic. Sows were inoculated with the strain of Haemophilus parasuis (serovars 4, 6 and 9 from Farms 1, 2 and 4, respectively) used for controlled challenge 3 and 5 weeks before farrowing. Before farrowing the sows were divided into control and treatment groups. Five to seven days after birth, the piglets of the treatment group were challenged with a strain from the farm which had were used to vaccinate the sows. The effectiveness of the controlled exposure was evaluated by number of piglets displaying clinical signs possibly related to infection, number of antibiotic treatments and pig mortality. Nasal swabs of sick pigs were taken twice a week to find a correlation to infection. A subsample of pigs was weighed after leaving the weaning sheds. The specificity of a realtime PCR amplifying the infB gene was evaluated with 68 H. parasuis isolates and 36 strains of closely related species. 239 samples of DNA from tissues and fluids of 16 experimentally challenged animals were also tested with the realtime PCR, and the results compared with culture and a conventional PCR. The farm experiments showed that none of the controlled challenge pigs showed any signs of illness due to Glasser's disease, although the treatment groups required more antibiotics than the controls. A total of 556 H. parasuis isolates were genotyped, while 150 isolates were serotyped. H. parasuis was detected on 19 of 20 farms, including 2 farms with an extensive history of freedom from Glasser's disease. Isolates belonging to serovars regarded as potentially pathogenic were obtained from healthy pigs at weaning on 8 of the 10 farms with a history of Glasser's disease outbreaks. Sampling 213 sick pigs yielded 115 isolates, 99 of which belonged to serovars that were either potentially pathogenic or of unknown pathogenicity. Only 16 isolates from these sick pigs were of a serovar known to be non-pathogenic. Healthy pigs also had H. parasuis, even on farms free of Glasser's disease. The realtime PCR gave positive results for all 68 H. parasuis isolates and negative results for all 36 non-target bacteria. When used on the clinical material from experimental infections, the realtime PCR produced significantly more positive results than the conventional PCR (165 compared to 86).

Comparative performance of Corymbia hybrids and parental species in subtropical Queensland and implications for breeding and deployment.

Eighty six full-sib Corymbia F1 hybrid families (crosses between C. torelliana and four spotted gum taxa: C. citriodora subsp. variegata, C. citriodora subsp. citriodora, C. henryi and C. maculata), were planted in six trials across six disparate sites in south-eastern Queensland to evaluate their productivity and determine their potential utility for plantation forestry. In each trial, the best-growing 20% of hybrid families grew significantly faster (P=0.05) than open-pollinated seedlots of the parent species Corymbia citriodora subsp. variegata, ranging from 107% to 181% and 127% to 287% of the height and diameter respectively. Relative performance of hybrid families growing on more than one site displayed consistency in ranking for growth across sites and analysis showed low genotype-by-environment interaction. Heritability estimates based on female and male parents across two sites at age six years for height and diameter at breast height, were high (0.62±0.28 to 0.64±0.35 and 0.31±0.21 to 0.69±0.37 respectively), and low to moderate (0.03±0.04 to 0.33±0.22) for stem straightness, branch size, incidence of ramicorns, and frost and disease resistance traits at ages one to three years. The proportion of dominance variance for height and diameter had reduced to zero by age six years. Based on these promising results, further breeding and pilot-scale family forestry and clonal forestry deployment is being undertaken. These results have also provided insights regarding the choice of a future hybrid breeding strategy.

Uneven application can influence the efficacy of s-methoprene against Rhyzopertha dominica (F.) in wheat.

The Juvenile Hormone analogue s-methoprene is used to protect stored grain from pests such as the lesser grain borer, Rhyzopertha dominica (F.). The possibility that uneven application influences s-methoprene efficacy against this species was investigated in the laboratory. Adults of methoprene-susceptible strains were exposed for 14 days to wheat treated at doses of up to 0.6 mg kg-1, or to mixtures of treated and untreated wheat giving equivalent average doses. Adult mortality after exposure to treated wheat was negligible in all cases (3.3%) and there was no significant effect of either average dose or evenness of application. In contrast, the number of adult progeny depended on both the average dose and evenness of application. Average doses of 0.3 and 0.6 mg kg-1 reduced the number of live F1 adults by 99-100% relative to the untreated wheat and no effect of evenness of application was detected. At lower doses, however, efficacy tended to decrease with increasing unevenness of application. When adults from the parental generation were transferred to untreated wheat for another 14 days neither the average dose nor evenness of application in the wheat from which they came had any significant effect on reproduction of these adults. This study demonstrates that uneven application can reduce the efficacy of s-methoprene against R. dominica, but that this is unlikely to influence the performance of s-methoprene against susceptible populations at target doses likely to be used in practice (e.g. 0.6 mg kg-1 in Australia). However, the possibility that uneven application leads to underdosing and selects for resistance should be investigated.

Stimulation of liver tryptophan pyrrolase during heat exposure

Exposure of rats to heat (39 +/- 1 degree C) stimulated liver tryptophan pyrrolase 2-fold between 3 and 48 h. Plasma corticosterone increased 2-fold after 1 h of heat exposure and decreased to a low value of 50% by 16 h. The effect of heat exposure on the enzyme was obtained in adrenalectomized animals. Stimulation by cortisol and tryptophan of the enzyme was also obtained in heat exposure, and the effects seemed to be additive. The concentration of tryptophan in the liver remained unchanged, and that in the plasma decreased to about 50% at 8 h exposure to heat and reverted to normal by 46 h. Simultaneous administration of noradrenaline to heat-exposed rats had no effect, whereas that of thyroxine partly prevented the stimulation of the enzyme activity. Hypothyroid conditions obtained by thyroidectomy or treatment with propylthiouracil significantly stimulated the enzyme activity. Cycloheximide treatment of heat-exposed rats did not prevent the stimulation of the enzyme activity. The results indicate that the effect of heat exposure on liver tryptophan pyrrolase is obtained, due to the accompanying hypothyroid condition, by increasing the activity of the existing protein by a mechanism possibly different from those known at present.

Heat exposure and hypothyroid conditions decrease hydrogen peroxide generation in liver mitochondria

Exposure of rats to heat (39 +/- 1 degree C) decreased H2O2 generation in mitochondria of the liver, but not of the kidney or the heart. The effect was obtained with three substrates, succinate, glycerol 1-phosphate and choline, with a decrease to 50% in the first 2-3 days of exposure, and a further decrease on longer exposure. The dehydrogenase activity with only glycerol 1-phosphate decreased, which is indicative of the hypothyroid condition, whereas choline dehydrogenase activity remained unchanged and that of succinate dehydrogenase decreased on long exposure. The serum concentration of thyroxine decreased in heat-exposed rats. Thyroxine treatment of rats increased H2O2 generation. Hypothyroid conditions obtained by treatment with propylthiouracil or thyroidectomy caused a decrease in H2O2 generation and changes in dehydrogenase activities similar to those with heat exposure. Treatment of heat-exposed or thyroidectomized rats with thyroxine stimulated H2O2 generation by a mechanism apparently involving fresh protein synthesis. The results indicate that H2O2 generation in mitochondria of heat-exposed animals is determined by thyroid status.

Controlled exposure as a management tool for Glassers disease

Control of bacterial disease of pigs.

Socioeconomic Status, Occupational Factors and Lifestyle as Predictors of Hospitalisation for Back Disorders

The aim of this dissertation was to examine the determinants of severe back disorders leading to hospital admission in Finland. First, back-related hospitalisations were considered from the perspective of socioeconomic status, occupation, and industry. Secondly, the significance of psychosocial factors at work, sleep disturbances, and such lifestyle factors as smoking and overweight was studied as predictors of hospitalisation due to back disorders. Two sets of data were used: 1) the population-based data comprised all occupationally active Finns aged 25-64, and included hospitalisations due to back disorders in 1996 and 2) a cohort of employees followed up from 1973 to 2000 having been hospitalised due to back disorders. The results of the population-based study showed that people in physically strenuous industries and occupations, such as agriculture and manufacturing, were at an increased risk of being hospitalised for back disorders. The lowest hospitalisation rates were found in sedentary occupations. Occupational class and the level of formal education were independently associated with hospitalisation for back disorders. This stratification was fairly consistent across age-groups and genders. Men had a slightly higher risk of becoming hospitalised compared with women, and the risk increased with age among both genders. The results of the prospective cohort study showed that psychosocial factors at work such as low job control and low supervisor support predicted subsequent hospitalisation for back disorders even when adjustments were made for occupational class and physical workload history. However, psychosocial factors did not predict hospital admissions due to intervertebral disc disorders; only admissions due to other back disorders. Smoking and overweight predicted, instead, only hospitalisation for intervertebral disc disorders. These results suggest that the etiological factors of disc disorders and other back disorders differ from each other. The study concerning the association of sleep disturbances and other distress symptoms with hospitalisation for back disorders revealed that sleep disturbances predicted subsequent hospitalisation for all back disorders after adjustment for chronic back disorders and recurrent back symptoms at baseline, as well as for work-related load and lifestyle factors. Other distress symptoms were not predictive of hospitalisation.

Impact of Tobacco Control Policy on Smoking and Exposure to Environmental Tobacco Smoke

The aim of the study was to evaluate the impact of the Finnish tobacco control measures for reduction of smoking. First, the trends and patterns in ever smoking among adult Finns in 1978 2001 as well as the associations of trends with the Tobacco Control Act in 1976 were examined. Secondly, the impact of the 1976 TCA on the proportion of ever daily smokers in different socioeconomic groups was studied. Thirdly, the impact of the 1995 TCAA on recent trends in the prevalence of daily smoking was evaluated by gender and employment status. Fourthly, the trends of exposure to environmental tobacco smoke (ETS) at workplaces and homes were investigated. The study is based on data of the Health Behaviour among the Finnish Adult Population surveys. Among Finnish men smoking initiation declined from earlier to later cohorts, whereas among women it increased in successive birth cohorts born before 1956. The lasting differences between birth cohorts as regards ever daily smoking reflected well the impact of measures to reduce smoking in Finland in 1976. Smoking initiation in the birth cohorts (born in 1961 or later) which were in critical age as regards the risk of smoking initiation when the TCA came into force was less common than could be expected according to the trends seen in the earlier birth cohorts. Marked socioeconomic differences were found in smoking in the different birth cohorts. Smoking was more prevalent in the lower socioeconomic groups than in the higher ones, and the differences were larger in the later birth cohorts compared to the earlier ones. The differences between the birth cohorts in ever daily smoking were compatible with the hypothetical impact of the TCA in almost all socioeconomic groups, except farmers. Among men the 1976 TCA appears to have had the greatest impact on white-collar employees. Among women the effect of the act was highly significant in all socioeconomic groups. However, female smoking prevalence continues to show wide socioeconomic disparities. Daily smoking decreased among employees after the 1995 TCAA, supporting the hypothesis of the lowering impact of the amendment on daily smoking due to increased smoking cessation. No parallel change in daily smoking was found in the population without direct expose to ETS legislation (farmers, students, housewives, pensioners or unemployed). Exposure to ETS decreased markedly among non-smokers at work after the 1995 TCAA. The 1976 TCA and the 1995 TCAA were useful in controlling smoking initiation and cessation, but their impact was not equal across the population groups. The results of this study strongly suggested that tobacco control policies markedly contribute to the decrease in smoking and in exposure to environmental tobacco smoke.

Multiple socioeconomic circumstances and health : associations and explanations among Finnish and British public sector employees

Socioeconomic health inequalities have been widely documented, with a lower social position being associated with poorer physical and general health and higher mortality. For mental health the results have been more varied. However, the mechanisms by which the various dimensions of socioeconomic circumstances are associated with different domains of health are not yet fully understood. This is related to a lack of studies tackling the interrelations and pathways between multiple dimensions of socioeconomic circumstances and domains of health. In particular, evidence from comparative studies of populations from different national contexts that consider the complexity of the causes of socioeconomic health inequalities is needed. The aim of this study was to examine the associations of multiple socioeconomic circumstances with physical and mental health, more specifically physical functioning and common mental disorders. This was done in a comparative setting of two cohorts of white-collar public sector employees, one from Finland and one from Britain. The study also sought to find explanations for the observed associations between economic difficulties and health by analysing the contribution of health behaviours, living arrangements and work-family conflicts. The survey data were derived from the Finnish Helsinki Health Study baseline surveys in 2000-2002 among the City of Helsinki employees aged 40-60 years, and from the fifth phase of the London-based Whitehall II study (1997-9) which is a prospective study of civil servants aged 35-55 years at the time of recruitment. The data collection in the two countries was harmonised to safeguard maximal comparability. Physical functioning was measured with the Short Form (SF-36) physical component summary and common mental disorders with the General Health Questionnaire (GHQ-12). Socioeconomic circumstances were parental education, childhood economic difficulties, own education, occupational class, household income, housing tenure, and current economic difficulties. Further explanatory factors were health behaviours, living arrangements and work-family conflicts. The main statistical method used was logistic regression analysis. Analyses were conducted separately for the two sexes and two cohorts. Childhood and current economic difficulties were associated with poorer physical functioning and common mental disorders generally in both cohorts and sexes. Conventional dimensions of socioeconomic circumstances i.e. education, occupational class and income were associated with physical functioning and mediated each other’s effects, but in different ways in the two cohorts: education was more important in Helsinki and occupational class in London. The associations of economic difficulties with health were partly explained by work-family conflicts and other socioeconomic circumstances in both cohorts and sexes. In conclusion, this study on two country-specific cohorts confirms that different dimensions of socioeconomic circumstances are related but not interchangeable. They are also somewhat differently associated with physical and mental domains of health. In addition to conventionally measured dimensions of past and present socioeconomic circumstances, economic difficulties should be taken into account in studies and attempts to reduce health inequalities. Further explanatory factors, particularly conflicts between work and family, should also be considered when aiming to reduce inequalities and maintain the health of employees.

The Europeanisation of occupational health services: A study of the impact of EU policies

This study concerns Framework Directive 89/391/EEC on health and safety at work, which encouraged improvements in occupational health services (OHS) for workers in EU member states. Framework Directive 89/391/EEC originally aimed at bringing the same level of occupational health and safety to employees in both the public and private sectors in EU member states. However, the implementation of the framework directive and OHS varies widely among EU member states. Occupational health services have generally been considered an important work-related welfare benefit in EU member states. The purpose of this study was to analyse OHS within the EU context and then analyse the impact of EU policies on OHS implementation as part of the welfare state benefit. The focus is on social, health, and industrial policies within welfare state regimes as well as EU policy-making processes affecting these policies in EU member states. The research tasks were divided into four groups related to the policy, functions, targets,and actors of OHS. The questions related to policy tried to discover the role of OHS in other policies, such as health, social, and labour market policies within the EU. The questions about functions sought to describe the changes, as well as the path dependence, of OHS in EU member states after the framework directive. The questions about targets were based on the general aims of WHO and the ILO in relation to equity, solidarity, universality, and access to OHS. The questions on actors were designed to understand the variety of stakeholders interested in OHS. The actors were supranational (EU, ILO, and WHO), national (ministries, institutes, and professional organisations), and social partners (trade unions and employers organisations). The study data were collected by interviewing 92 people in 15 EU member states, including representatives of ministries, institutions, research,trade unions, employers organisations, and occupational health organisations. Other documents were collected from the Internet,databases, libraries, and conference materials for a systematic review of the policies, strategies, organisation, financing, and monitoring of OHS in EU member states. Different analytical methods were used in the data analysis. The main findings of the study can be summarised as follows. First, occupational health services is a context-dependent phenomenon, which therefore varies according to the development of the welfare state in general, and depends on each country s culture, history, economy, and politics. The views of different stakeholders in EU member states concerning the impact and possibilities of OHS to improve health vary from evidence-based opinions to the sporadic impact of OHS on occupational health. OHS as a concept is vaguely defined by the EU, whereas the ILO defines OHS content. The tasks of OHS began as preventive and protective services for workers. However, they have moved towards multidisciplinary and organisational development as well as the workplace health promotion sphere.Since 1989 OHS has developed differently in different EU member states depending on the starting position of those states, but planning and implementation are crucial phases in the process toward better OHS coverage, equity, and access. Nevertheless, the data used for the planning and legitimisation of OHS activities are mainly based on occupational health data rather than on OHS data. This makes decisions on political or policy grounds inaccurate. OHS is still an evolving concept and benefit for workers, but the Europeanisation of OHS reflects contextual changes, such as the impact of the internal market, competition, and commercialisation on OHS. Stronger cooperation and integration with health, social, and employment services would be an asset for workers, because of new epidemics, an epidemiological shift towards new risks, an ageing labour market, and changes in the labour market. Different methods and approaches are needed in order to study the results of integrated services. In the future, more detailed information will be needed about the actual impact of EU policies on OHS and decision-making processes in order to get OHS into different policies in the EU and its member states. Further results and effects of OHS processes on occupational health need to be analysed more carefully. The adoption of a variety of research strategies and a multidisciplinary approach to understand the influence of different policies on OHS in the EU and its member states would highlight the options and opportunities to improve workers occupational health. Key subject headings: Occupational health services, EU policy, policymaking,framework directive 89/391/EEC

A variant in LIN28B is associated with 2D:4D finger-length ratio, a putative retrospective biomarker of prenatal testosterone exposure

The ratio of the lengths of an individual's second to fourth digit (2D:4D) is commonly used as a noninvasive retrospective biomarker for prenatal androgen exposure. In order to identify the genetic determinants of 2D:4D, we applied a genome-wide association approach to 1507 11-year-old children from the Avon Longitudinal Study of Parents and Children (ALSPAC) in whom 2D:4D ratio had been measured, as well as a sample of 1382 12- to 16-year-olds from the Brisbane Adolescent Twin Study. A meta-analysis of the two scans identified a single variant in the LIN28B gene that was strongly associated with 2D:4D (rs314277: p = 4.1 x 10(-8)) and was subsequently independently replicated in an additional 3659 children from the ALSPAC cohort (p = 1.53 x 10(-6)). The minor allele of the rs314277 variant has previously been linked to increased height and delayed age at menarche, but in our study it was associated with increased 2D:4D in the direction opposite to that of previous reports on the correlation between 2D:4D and age at menarche. Our findings call into question the validity of 2D:4D as a simplistic retrospective biomarker for prenatal testosterone exposure.

Reproduction of phosphine resistant Rhyzopertha dominica (F.) following sublethal exposure to phosphine.

Phosphine fumigation is commonly used to disinfest grain of insect pests. In fumigations which allow insect survival the question of whether sublethal exposure to phosphine affects reproduction is important for predicting population recovery and the spread of resistance. Two laboratory experiments addressed this question using strongly phosphine resistant lesser grain borer, Rhyzopertha dominica (F.). Offspring production was examined in individual females which had been allowed to mate before being fumigated for 48 h at 0.25 mg L -1. Surviving females produced offspring but at a reduced rate during a two-week period post fumigation compared to unfumigated controls. Cumulative fecundity of fumigated females from 4 weeks of oviposition post fumigation was 25% lower than the cumulative fecundity of unfumigated females. Mating potential post fumigation was examined when virgin adults (either or both sexes) were fumigated individually (48 h at 0.25 mg L -1) and the survivors were allowed to mate and reproduce in wheat. All mating combinations produced offspring but production in the first week post fumigation was significantly suppressed compared to the unfumigated controls. Offspring suppression was greatest when both sexes were exposed to phosphine followed by the pairing of fumigated females with unfumigated males and the least suppression was observed when males only were fumigated. Cumulative fecundity from 4 weeks oviposition post fumigation of fumigated females paired with fumigated males was 17% lower than the fecundity of unfumigated adult pairings. Both of these experiments confirmed that sublethal exposure to phosphine can reduce fecundity in R. dominica.

Sublethal Exposure to Phosphine Decreases Offspring Production in Strongly Phosphine Resistant Female Red Flour Beetles, Tribolium castaneum (Herbst)

The red flour beetle is a cosmopolitan pest of stored grain and stored grain products. The pest has developed resistance to phosphine, the primary chemical used for its control. The reproductive output of survivors from a phosphine treatment is an important element of resistance development but experimental data are lacking. We exposed mated resistant female beetles to 0.135 mg/L of phosphine for 48 h at 25°C. Following one week of recovery we provided two non-exposed males to half of the phosphine exposed females and to half of the non-exposed control females. Females that had been exposed produced significantly fewer offspring than non-exposed females. Females that remained isolated produced significantly fewer offspring than both exposed females with access to males and non-exposed controls (P<0.05). Some females were permanently damaged from exposure to phosphine and did not reproduce even when given access to males. We also examined the additional effects of starvation prior to phosphine exposure on offspring production. Non-exposed starved females experienced a small reduction in mean offspring production in the week following starvation, followed by a recovery in the second week. Females that were starved and exposed to phosphine demonstrated a very significant reduction in offspring production in the first week following exposure which remained significantly lower than that of starved non-exposed females (P<0.05). These results demonstrate a clear sublethal effect of phosphine acting on the female reproductive system and in some individuals this can lead to permanent reproductive damage. Pest population rebound after a fumigation may be slower than expected which may reduce the rate of phosphine resistance development. The results presented strongly suggest that phosphine resistance models should include sublethal effects. © 2012 Ridley et al.