An Overview of Traceback Investigations and Three Case Studies of Recent Outbreaks of Escherichia coli O157:H7 Infections Linked to Romaine Lettuce.

ABSTRACT: Leafy greens contaminated with Shiga toxin-producing Escherichia coli have continued to cause foodborne illness outbreaks in recent years and present a threat to public health. An important component of foodborne illness outbreak investigations is determining the source of the outbreak vehicle through traceback investigations. The U.S. Food and Drug Administration is home to traceback investigation experts who use a standardized process to initiate, execute, and interpret the results of traceback investigations in collaboration with the Centers for Disease Control and Prevention and state and local partners. Traceback investigations of three outbreaks of Shiga toxin-producing E. coli infections linked to romaine lettuce in 2018 and 2019 were examined to demonstrate challenges, limitations, and opportunities for improvement. The three outbreaks resulted in a total of 474 illnesses, 215 hospitalizations, and 5 deaths. These illnesses were linked to the consumption of romaine lettuce from three distinct growing regions in Arizona and California. Some of the challenges encountered included the time it took to initiate a traceback, limited product-identifying information throughout the supply chain, lack of interoperability in record-keeping systems, and comingling of product from multiple suppliers. These challenges led to time delays in the identification of the farm source of the leafy greens and the inability to identify the root cause of contamination. Implementation of technology-enabled traceability systems, testing of these systems, and future regulations to incentivize adoption of traceability systems are some of the initiatives that will help address these challenges by improving traceback investigations and ultimately preventing foodborne illnesses and future outbreaks from occurring.

Gender differences in the influence of economic, lifestyle, and psychosocial factors on later-life health.

BACKGROUND: Gender differences in exposure to social resources play a significant role in influencing gender inequalities in health. A related question--and our focus--asks whether these inequalities are also influenced by gendered vulnerabilities to social forces. Specifically, this paper examines the differential impact of social forces on the health of elderly (65+) men and women. METHODS: Multiple linear regression analysis is used to estimate gender differences in the influence of socioeconomic, lifestyle, and psychosocial factors on both self-rated health and overall functional health using data from the 1994-1995 National Population Health Survey. RESULTS: Key findings include: 1) the relationship between income and health is significant for older women only, whereas the converse holds for education; 2) having an acceptable body weight is positively associated with health for elderly women only; and 3) stress-related factors are stronger determinants of health for older women. INTERPRETATION: Our findings shed light on the processes of healthy aging for men and women, and suggest that interventions to improve the health of elderly Canadians need to be gender-specific.

Examining the healthy immigrant effect in mid- to later life: findings from the Canadian Community Health Survey.

Recent studies have established that a healthy immigrant effect operates in Canada-immigrants are generally healthier than Canadian-born persons-but that this effect tends to diminish over time, as the health of immigrants converges to the Canadian norm. Although this effect has been examined by place of birth, language, marital status, socio-economic status, charter-language ability, and category of immigrant status in Canada, less is known about the healthy immigrant effect at different stages of the life course, particularly in mid- to later adulthood, stages at which there is an increased likelihood of decline in physical and mental health status. This study examines how age at immigration affects the health of mid- to later-life immigrants, compared to Canadian-born persons, using data from the 2000-2001 Canadian Community Health Survey. These data indicate that the healthy immigrant effect applies to later mid-life immigrants; that is, new immigrants-those who immigrated less than 10 years ago-aged 45 to 64 have better health than their longer-term counterparts-those who immigrated 10 or more years ago-whose health status is similar to that of Canadian-born persons. Interestingly, a different picture emerges in old age (65 years and over), where recent immigrants have poorer overall health compared to Canadian-born persons. When a number of socio-demographic, socio-economic, and health behaviour factors are controlled, however, this disadvantage largely disappears. The findings are discussed in terms of their implications for Canadian health care policy and program planning for immigrants in the latter stages of the life course.

"There's no place like home": an analysis of young adults' mature coresidency in Canada.

This article investigates the propensity for young adults to live in the parental home between the ages of 25 to 34--termed "mature coresidency." Drawing upon a synthesis of life course theory and the concept of social capital, a rationale is developed for examination of emotional closeness to parents during childhood and a number of socio-demographic and structural factors deemed to be important. Using a subset of young adults aged 25 to 34 (N = 1,760) from the 1995 Canadian General Social Survey, it is found that emotional closeness to mothers and fathers are major determinants of mature coresidency. Other important predictors include child's age, gender, marital status, and several family background factors. The implications of the findings are discussed for transitions to adulthood and family development against a changing social and economic landscape.