Myths, models and mitigation of resistance to pesticides.
Resistance to pesticides in arthropod pests is a significant economic, ecological and public health problem. Although extensive research has been conducted on diverse aspects of pesticide resistance and we have learned a great deal during the past 50 years, to some degree the discussion about 'resistance management' has been based on 'myths'. One myth involves the belief that we can manage resistance. I will maintain that we can only attempt to mitigate resistance because resistance is a natural evolutionary response to environmental stresses. As such, resistance will remain an ongoing dilemma in pest management and we can only delay the onset of resistance to pesticides. 'Resistance management' models and tactics have been much discussed but have been tested and deployed in practical pest management programmes with only limited success. Yet the myth persists that better models will provide a 'solution' to the problem. The reality is that success in using mitigation models is limited because these models are applied to inappropriate situations in which the critical genetic, ecological, biological or logistic assumptions cannot be met. It is difficult to predict in advance which model is appropriate to a particular situation; if the model assumptions cannot be met, applying the model sometimes can increase the rate of resistance development rather than slow it down. Are there any solutions? I believe we already have one. Unfortunately, it is not a simple or easy one to deploy. It involves employing effective agronomic practices to develop and maintain a healthy crop, monitoring pest densities, evaluating economic injury levels so that pesticides are applied only when necessary, deploying and conserving biological control agents, using host-plant resistance, cultural controls of the pest, biorational pest controls, and genetic control methods. As a part of a truly multi-tactic strategy, it is crucial to evaluate the effect of pesticides on natural enemies in order to preserve them in the cropping system. Sometimes, pesticide-resistant natural enemies are effective components of this resistance mitigation programme. Another name for this resistance mitigation model is integrated pest management (IPM). This complex model was outlined in some detail nearly 40 years ago by V. M. Stern and colleagues. To deploy the IPM resistance mitigation model, we must admit that pest management and resistance mitigation programmes are not sustainable if based on a single-tactic strategy. Delaying resistance, whether to traditional pesticides or to transgenic plants containing toxin genes from Bacillus thuringiensis, will require that we develop multi-tactic pest management programmes that incorporate all appropriate pest management approaches. Because pesticides are limited resources, and their loss can result in significant social and economic costs, they should be reserved for situations where they are truly needed--as tools to subdue an unexpected pest population outbreak. Effective multi-tactic IPM programmes delay resistance (= mitigation) because the number and rates of pesticide applications will be reduced. (+info
The expiry date of man: a synthesis of evolutionary biology and public health.
In industrialised countries, mortality and morbidity are dominated by age related chronic degenerative diseases. The health and health care needs of future populations will be heavily determined by these conditions of old age. Two opposite scenarios of future morbidity exist: morbidity might decrease ("compress"), because life span is limited, and the incidence of disease is postponed. Or morbidity might increase ("expand"), because death is delayed more than disease incidence. Optimality theory in evolutionary biology explains senescence as a by product of an optimised life history. The theory clarifies how senescence is timed by the competing needs for reproduction and survival, and why this leads to a generalised deterioration of many functions at many levels. As death and disease are not independent, future morbidity will depend on duration and severity of the process of senescence, partly determined by health care, palliating the disease severity but increasing the disease duration by postponing death. Even if morbidity might be compressed, health care needs will surely expand. (+info
Dietary intake and practices in the Hong Kong Chinese population.
OBJECTIVES: To examine dietary intake and practices of the adult Hong Kong Chinese population to provide a basis for future public health recommendations with regard to prevention of certain chronic diseases such as cardiovascular disease, hypertension, and osteoporosis. PARTICIPANTS: Age and sex stratified random sample of the Hong Kong Chinese population aged 25 to 74 years (500 men, 510 women). METHOD: A food frequency method over a one week period was used for nutrient quantification, and a separate questionnaire was used for assessment of dietary habits. Information was obtained by interview. RESULTS: Men had higher intakes of energy and higher nutrient density of vitamin D, monounsaturated fatty acids and cholesterol, but lower nutrient density of protein, many vitamins, calcium, iron, copper, and polyunsaturated fatty acids. There was an age related decrease in energy intake and other nutrients except for vitamin C, sodium, potassium, and percentage of total calorie from carbohydrate, which all increased with age. Approximately 50% of the population had a cholesterol intake of < or = 300 mg; 60% had a fat intake < or = 30% of total energy; and 85% had a percentage of energy from saturated fats < or = 10%; criteria considered desirable for cardiovascular health. Seventy eight per cent of the population had sodium intake values in the range shown to be associated with the age related rise in blood pressure with age. Mean calcium intake was lower than the FAO/WHO recommendations. The awareness of the value of wholemeal bread and polyunsaturated fat spreads was lower in this population compared with that in Australia. There was a marked difference in types of cooking oil compared with Singaporeans, the latter using more coconut/palm/mixed vegetable oils. CONCLUSION: Although the current intake pattern for cardiovascular health for fat, saturated fatty acid, and cholesterol fall within the recommended range for over 50% of the population, follow up surveys to monitor the pattern would be needed. Decreasing salt consumption, increasing calcium intake, and increasing the awareness of the health value of fibre may all be beneficial in the context of chronic disease prevention. (+info
Bioterrorism alleging use of anthrax and interim guidelines for management--United States, 1998.
From October 30 through December 23, 1998, CDC received reports of a series of bioterroristic threats of anthrax exposure. Letters alleged to contain anthrax were sent to health clinics on October 30, 1998, in Indiana, Kentucky, and Tennessee. During December 17-23 in California, a letter alleged to contain anthrax was sent to a private business, and three telephone threats of anthrax contamination of ventilation systems were made to private and public buildings. All threats were hoaxes and are under investigation by the Federal Bureau of Investigation (FBI) and local law enforcement officials. The public health implications of these threats were investigated to assist in developing national public health guidelines for responding to bioterrorism. This report summarizes the findings of these investigations and provides interim guidance for public health authorities on bioterrorism related to anthrax. (+info
Cancer mortality by educational level in the city of Barcelona.
The objective of this study was to examine the relationship between educational level and mortality from cancer in the city of Barcelona. The data were derived from a record linkage between the Barcelona Mortality Registry and the Municipal Census. The relative risks (RR) of death and 95% confidence intervals (CIs) according to level of education were derived from Poisson regression models. For all malignancies, men in the lowest educational level had a RR of death of 1.21 (95% CI 1.13-1.29) compared with men with a university degree, whereas for women a significant decreasing in risk was observed (RR 0.81; 95% CI 0.74-0.90). Among men, significant negative trends of increasing risk according to level of education were present for cancer of the mouth and pharynx (RR 1.70 for lowest vs. highest level of education), oesophagus (RR 2.14), stomach (RR 1.99), larynx (RR 2.56) and lung (RR 1.35). Among women, cervical cancer was negatively related to education (RR 2.62), whereas a positive trend was present for cancers of the colon (RR 0.76), pancreas (RR 0.59), lung (RR 0.55) and breast (RR 0.65). The present study confirms for the first time, at an individual level, the existence of socioeconomic differences in mortality for several cancer sites in Barcelona, Spain. There is a need to implement health programmes and public health policies to reduce these inequities. (+info
Respiratory tract infections as a public health challenge.
Acute respiratory infections have everywhere become the province of clinicians and the pharmaceutical industry. A public health approach is needed with systematic efforts to minimize transmission, maximize prevention, and harness the research and surveillance effort to decrease their incidence and severity. These infections have a huge incidence, morbidity burden, and economic impact in all societies. Several factors now demand renewed attention to prevention. They include the growing costs and potentially limited benefits of an expanded pharmacotherapeutic approach; the serious change in antibiotic susceptibility of the common respiratory pathogens; the advances made in vaccinology in recent years; and the need to promote equity and share limited health resources across the world's population. Care should not be restricted to those in affluent countries who can afford increasingly expensive treatment. (+info
The US Food and Drug Administration investigational device exemptions (IDE) and clinical investigation of cardiovascular devices: information for the investigator.
The conduct of a clinical investigation of a medical device to determine the safety and effectiveness of the device is covered by the investigational device exemptions (IDE) regulation. The purpose of IDE regulation is "to encourage, to the extent consistent with the protection of public health and safety and with ethical standards, the discovery and development of useful devices intended for human use, and to that end to maintain optimum freedom for scientific investigators in their pursuit of this purpose" (Federal Food, Drug, and Cosmetic Act). Conducting a clinical investigation may require an approved IDE application. The US Food and Drug Administration encourages early interaction with the agency through the pre-IDE process during the development of a device or technology and during the preparation of an IDE application. This facilitates approval of the IDE application and progression into the clinical investigation. This paper reviews the terminology and applicability of the IDE regulation and the type of study that requires an IDE application to the Food and Drug Administration. The pre-IDE process and the development of an IDE application for a significant risk study of a cardiovascular device are discussed. (+info
Skirting the issue: women and international health in historical perspective.
Over the last decades women have become central to international health efforts, but most international health agencies continue to focus narrowly on the maternal and reproductive aspects of women's health. This article explores the origins of this paradigm as demonstrated in the emergence of women's health in the Rockefeller Foundation's public health programs in Mexico in the 1920s and 1930s. These efforts bore a significant reproductive imprint; women dispensed and received services oriented to maternal and childbearing roles. Women's health and social advocacy movements in Mexico and the United States partially shaped this interest. Even more important, the emphasis on women in the Rockefeller programs proved an expedient approach to the Foundation's underlying goals: promoting bacteriologically based public health to the government, medical personnel, business interests, and peasants; helping legitimize the Mexican state; and transforming Mexico into a good political and commercial neighbor. The article concludes by showing the limits to the maternal and reproductive health model currently advocated by most donor agencies, which continue to skirt--or sidestep--major concerns that are integral to the health of women. (+info