Modelling the Wolbachia incompatible insect technique: strategies for effective mosquito population elimination.

BACKGROUND: The Wolbachia incompatible insect technique (IIT) shows promise as a method for eliminating populations of invasive mosquitoes such as Aedes aegypti (Linnaeus) (Diptera: Culicidae) and reducing the incidence of vector-borne diseases such as dengue, chikungunya and Zika. Successful implementation of this biological control strategy relies on high-fidelity separation of male from female insects in mass production systems for inundative release into landscapes. Processes for sex-separating mosquitoes are typically error-prone and laborious, and IIT programmes run the risk of releasing Wolbachia-infected females and replacing wild mosquito populations. RESULTS: We introduce a simple Markov population process model for studying mosquito populations subjected to a Wolbachia-IIT programme which exhibit an unstable equilibrium threshold. The model is used to study, in silico, scenarios that are likely to yield a successful elimination result. Our results suggest that elimination is best achieved by releasing males at rates that adapt to the ever-decreasing wild population, thus reducing the risk of releasing Wolbachia-infected females while reducing costs. CONCLUSIONS: While very high-fidelity sex separation is required to avoid establishment, release programmes tend to be robust to the release of a small number of Wolbachia-infected females. These findings will inform and enhance the next generation of Wolbachia-IIT population control strategies that are already showing great promise in field trials.

Screening for the metabolic syndrome in community psychiatric patients prescribed antipsychotics: a quality improvement programme.

OBJECTIVE: The aim was to evaluate a quality improvement programme designed to increase screening for the metabolic syndrome in community psychiatric patients prescribed antipsychotics. METHOD: Baseline audit against evidence-based standards, followed by provision of benchmarked data and a range of change interventions, with re-audit 1 year later. RESULTS: At baseline, 48 assertive outreach teams across the UK submitted data on screening over the previous year for 1966 patients. At re-audit, 35 of the teams submitted data for 1516 patients. Screening for all four aspects of the metabolic syndrome (measuring blood pressure, obesity, blood glucose and plasma lipids) had increased significantly by re-audit. Clinical variables increasing the likelihood of full screening were clozapine treatment and a known diagnosis of diabetes or dyslipidaemia. CONCLUSION: The programme's success may be partly attributed to the use of a widely-accepted audit standard, and bespoke change interventions that directly addressed barriers to screening identified by the participating clinical teams.

Area characteristics and individual-level socioeconomic position indicators in three population-based epidemiologic studies.

PURPOSE: There is growing interest in incorporating area indicators into epidemiologic analyses. Using data from the 1990 U.S. Census linked to individual-level data from three epidemiologic studies, we investigated how different area indicators are interrelated, how measures for different sized areas compare, and the relation between area and individual-level social position indicators. METHODS: The interrelations between 13 area indicators of wealth/income, education, occupation, and other socioenvironmental characteristics were investigated using correlation coefficients and factor analyses. The extent to which block-group measures provide information distinct from census tract measures was investigated using intraclass correlation coefficients. Loglinear models were used to investigate associations between area and individual-level indicators. RESULTS: Correlations between area measures were generally in the 0.5--0.8 range. In factor analyses, six indicators of income/wealth, education, and occupation loaded on one factor in most geographic sites. Correlations between block-group and census tract measures were high (correlation coefficients 0.85--0.96). Most of the variability in block-group indicators was between census tracts (intraclass correlation coefficients 0.72--0.92). Although individual-level and area indicators were associated, there was evidence of important heterogeneity in area of residence within individual-level income or education categories. The strength of the association between individual and area measures was similar in the three studies and in whites and blacks, but blacks were much more likely to live in more disadvantaged areas than whites. CONCLUSIONS: Area measures of wealth/income, education, and occupation are moderately to highly correlated. Differences between using census tract or block-group measures in contextual investigations are likely to be relatively small. Area and individual-level indicators are far from perfectly correlated and provide complementary information on living circumstances. Differences in the residential environments of blacks and whites may need to be taken into account in interpreting race differences in epidemiologic studies.

Mobile medics? The mobility of doctors in the European Economic Area.

The Treaty of Rome seeks to generate a common European market whereby all barriers to the free movement of produce, capital, services and labour are removed. Current EU policy on the free movement of labour requires that healthcare workers, who are EU citizens and meet certain training criteria, have the right to register to practice in member states other than the one in which they trained. This policy is underpinned by the EEC Directives. For example, the Medical Directive 93/16/EEC describes the framework for the mutual recognition of medical diplomas, certificates and other evidence of qualifications through out the European Economic Area (EEA). The potential impact of this for health policy is clear-workforce planning and the demand for doctors, (and also nurses and other health care professionals), could be particularly affected by new forces impacting on their supply. This paper reports on the reality of labour mobility today, and on the factors upon which mobility depends, by the means of a case study which, investigated the movement into UK of doctors from the EEA. At a formal level there is mutual recognition of diplomas, certificates and other evidence of qualifications. However, formal and 'real life' recognition could be in tension equating in policy terms to an implementation deficit. As a result, there is a 'mixed picture' which makes predicting the future (both for individual countries and for the European Union) even more difficult. Furthermore, different policy objectives have to be reconciled. Do we want high mobility; or do we want to preserve national manpower planning?

Workforce planning. Catching the drift.

NHS workforce planning has traditionally ignored the role of doctors and nurses trained in continental Europe and Scandinavia. At present doctors trained in the European Economic Area make up 10 per cent of senior house officers in England and Wales. But the numbers coming to the UK are falling. Falling medical unemployment in Europe will mean these doctors have less incentive to come to the UK, leaving a considerable gap in the NHS workforce. More local research is needed into working patterns and career plans of European-trained nurses and doctors.

Necessary conditions for a socialist health service.

A socialist health service in a non-socialist society may be forced to stress care and rescue rather than prevention, health maintenance or the promotion of better health and more equal health status. A socialist health service ought to be 'integrated'. A socialist health service ought to provide universal and comprehensive care.

NHS reforms. Counting the costs.

Localism predominates in purchaser-provider relationships, with markets strictly limited in practice. Block contracting predominates, largely to enable purchasers to bring pressure to bear on providers' costs and outputs. The administrative costs of operating the purchaser-provider split have led to a clear growth in the overall administrative costs within the NHS. Locality commissioning may conflict with the need to reorganise clinical services.

Present dangers and future threats: some perverse incentives in the NHS reforms.

The NHS reforms have come to mean all things to all men (and women). Identifying a market oriented purchaser-provider split as the conceptual heart of the reforms is still, however, useful. There are important perverse incentives in and around the NHS that are associated with the reforms; furthermore, many reactions to the resulting problems are paradoxical and often counterproductive. Hitherto most criticism of the reforms from the health policy and management community (as opposed to the professions and the public) has been tactical rather than fundamental. There are serious problems for the NHS associated both with the NHS market and with current, often tacit, strategies for the future of the service.