A systems analysis of irrigation water quality in an environmental assessment of an E. coli O157:H7 outbreak in the United States linked to iceberg lettuce.

A foodborne Escherichia coli O157:H7 outbreak in December 2006 included 77 illnesses reported in Iowa and Minnesota. Epidemiologic investigations by health departments in those states and the U.S. Centers for Disease Control and Prevention (CDC) identified shredded iceberg lettuce (Lactuca sativa L.) as the vehicle of transmission. The U.S. Food and Drug Administration (FDA) and Minnesota and California public health agencies traced the lettuce to several growing regions in California based on information from a lettuce processor in Minnesota. Samples from an environmental investigation initiated by the California Food Emergency Response Team (CalFERT) revealed a genetic match between the outbreak strain and environmental samples from a single farm, leading to an in-depth systems-based analysis of the irrigation water system on that farm. This paper presents findings from that systems-based analysis, which assessed conditions on the farm potentially contributing to contamination of the lettuce. The farm had three sources of irrigation water: groundwater from onsite wells, surface water delivered by a water management agency and effluent from wastewater lagoons on nearby dairy farms. Wastewater effluent was blended with the other sources and used only to irrigate animal feed crops. However, water management on the farm, including control of wastewater blending, appeared to create potential for cross-contamination. Pressure gradients and lack of backflow measures in the irrigation system might have created conditions for cross-contamination of water used to irrigate lettuce. The irrigation network on the farm had evolved over time to meet various needs, without an overall analysis of how that evolution potentially created vulnerabilities to contamination of irrigation water. The type of systems analysis described here is one method for helping to ensure that such vulnerabilities are identified and addressed. A preventive, risk-based management approach, such as the Water Safety Plan process for drinking water, may also be useful in managing irrigation water quality.

Market forces and organizational evolution at freestanding children's hospitals in the United States.

OBJECTIVES: To describe market forces that affect freestanding children's hospitals, to describe the development of formal business relationships among these hospitals and pediatricians and other health care delivery organizations, and to explore the impact of such changes on the roles and missions of these hospitals. METHODS: All freestanding children's hospitals in the United States in 1991 were identified (n = 44). A survey was mailed to the chief executive officer of each hospital. Data were collected for the period of 1991 through 1996. Twenty-nine of the 44 hospitals surveyed responded. RESULTS: Twenty-seven (93.1%) of the 29 hospitals reported an increase in competition and a more advanced stage of market evolution. Twenty-five hospitals (86.2%) developed at least one type of business relationship with pediatricians or another health care organization. Twenty-one (72.4%) developed a network of pediatricians. Seventeen (58.6%) developed a relationship with an adult-focused health care organization. There were no significant differences in teaching, research, or charity care activities between those respondents that developed a pediatric network and those that did not or between those respondents that integrated with adult-focused health care organization and those that did not. CONCLUSIONS: Nearly all freestanding children's hospitals developed new business relationships with physicians and other health care organizations. These new relationships were not associated with any significant changes in teaching, research, or charity care.

Prevalence and impact of caregiving: a detailed comparison between dementia and nondementia caregivers.

Analyzing data from more than 1,500 family caregivers from the 1996 National Caregiver Survey, this study documents the ways in which dementia care is different from other types of family caregiving. Not only do dementia caregivers spend significantly more hours per week providing care than nondementia caregivers, they also report greater impacts in terms of employment complications, caregiver strain, mental and physical health problems, time for leisure and other family members, and family conflict. Differential impacts remain even after controlling for intensity of caregiving involvement and sociodemographic factors. Study findings suggest the need to tailor programs and services to the unique challenges faced by dementia caregivers.

Rapid, easy, and economical screening test for antibodies to human immunodeficiency virus.

A new dot enzyme immunoassay (EIA) with a conserved portion of the envelope protein of the human immunodeficiency virus (HIV) as antigen has been designed for use in areas with few laboratory facilities and by personnel with little laboratory experience. Sera were tested in 263 subjects who had AIDS or AIDS-related complex or were at-risk or not-at-risk of AIDS from the USA, Africa, and Asia/Oceania. The dot EIA was 100% sensitive in the American subjects, and there were only 2 false negatives in the others, both of which were negative by commercial EIA. The test is simple to perform, economical, rapid (30 min), and stable.