Sean F. Altekruse

Vibrio parahaemolyticus Infections in the United States, 1973–1998

Vibrio parahaemolyticus infections are associated with consumption of raw or undercooked shellfish, contaminated food, and exposure of wounds to warm seawater. Foodborne outbreaks and sporadic infections from Vibrio species in 4 Gulf Coast states are reported routinely to the Centers for Disease Control and Prevention (CDC). Between 1988 and 1997, 345 sporadic V. parahaemolyticus infections were reported: 59% were gastroenteritis, 34% were wound infections, 5% were septicemia, and 2% were from other exposures. Forty-five percent of patients suffering from these conditions were hospitalized for their infections, and 88% of persons with acute gastroenteritis reported having eaten raw oysters during the week before their illness occurred. Between 1973 and 1998, 40 outbreaks of V. parahaemolyticus infections were reported to the CDC, and these outbreaks included >1000 illnesses. Most of these outbreaks occurred during the warmer months and were attributed to seafood, particularly shellfish. The median attack rate among persons who consumed the implicated seafood was 56%. To prevent V. parahaemolyticus infections, persons should avoid consumption of raw or undercooked shellfish and exposure of wounds to seawater.

The Role of Gulf Coast Oysters Harvested in Warmer Months in Vibrio vulnificus Infections in the United States, 1988–1996

Vibrio vulnificus infections are highly lethal and associated with consumption of raw shellfish and exposure of wounds to seawater. V. vulnificus infections were reported to the Centers for Disease Control and Prevention from 23 states. For primary septicemia infections, oyster trace-backs were performed and water temperature data obtained at harvesting sites. Between 1988 and 1996, 422 infections were reported; 45% were wound infections, 43% primary septicemia, 5% gastroenteritis, and 7% from undetermined exposure. Eighty-six percent of patients were male, and 96% with primary septicemia consumed raw oysters. Sixty-one percent with primary septicemia died; underlying liver disease was associated with fatal outcome. All trace-backs with complete information implicated oysters harvested in the Gulf of Mexico; 89% were harvested in water >22 degrees C, the mean annual temperature at the harvesting sites (P < .0001). Control measures should focus on the increased risk from oysters harvested from the Gulf of Mexico during warm months as well as education about host susceptibility factors.

A multi-state survey of consumer food-handling and food-consumption practices

INTRODUCTIONnIn the United States, foodborne infections cause an estimated 6.5-33 million illnesses a year. Also included in the burden of foodborne illnesses are sequelae such as hemolytic uremic syndrome, Guillain-Barré syndrome, and reactive arthritis. Surveillance for risky food-handling and food-consumption practices can be used to identify high-risk populations, develop educational efforts, and evaluate progress toward risk reduction.nnnDESIGNnIn 1995 and 1996, Behavioral Risk Factor Surveillance System interviews of 19,356 adults in eight states (1995: Colorado, Florida, Missouri, New York, and Tennessee; 1996: Indiana, New Jersey, and South Dakota) included questions related to food-handling and/or food-consumption practices. Risky food-handling and food-consumption practices were not uncommon. Overall, 19% of respondents did not adequately wash hands or cutting boards after contact with raw meat or chicken. During the previous year, 20% ate pink hamburgers, 50% ate undercooked eggs, 8% ate raw oysters, and 1% drank raw milk. Men were more likely to report risky practices than women. The prevalence of most risky behaviors increased with increasing socioeconomic status.nnnCONCLUSIONnTargeted education efforts may reduce the frequency of these behaviors. Periodic surveillance can be used to assess effectiveness. In addition to consumer education, prevention efforts are needed throughout the food chain including on the farm, in processing, distribution, and at retail.

Cheese-associated outbreaks of human illness in the United States, 1973 to 1992 : Sanitary manufacturing practices protect consumers

To identify contributing factors for cheese-associated outbreaks, we reviewed all cheese-associated outbreaks of human illness reported to the Centers for Disease Control and Prevention (CDC) with onsets during 1973 to 1992. The infrequency of large, cheese-associated outbreaks was notable because such outbreaks had been a frequent public health problem before the mid-20th century. Of 32 reported cheese-associated outbreaks, 11 attributed to manufacturing errors caused most of the illnesses and hospitalizations and all 58 deaths. Important factors in these 11 outbreaks were manufacturing cheese with raw or improperly pasteurized milk and postpasteurization contamination. If current Food and Drug Administration sanitary requirements for cheesemaking had been met, these outbreaks would have been preventable. In two outbreaks of Salmonella infections, fewer than 10 Salmonella per 100 g of cheese were detected. In two outbreaks of Brucella infections, efforts to recover the pathogen from the implicated cheese were unsuccessful, emphasizing the inadequacy of end product testing for assuring consumer safety. Curing cheeses kills most bacteria present in cheeses; however, evidence from sources other than the CDC Foodborne Disease Outbreak Surveillance System suggests that curing alone may not be a sufficient pathogen control step to eliminate Salmonella, Listeria, and E. coli O157:H7 from cheese.

Vibrio gastroenteritis in the US Gulf of Mexico region: the role of raw oysters

We examined clinical and epidemiological features of 575 laboratory-confirmed cases of vibrio gastroenteritis in Alabama, Florida, Louisiana, and Texas from 1988 to 1997 (the US Gulf of Mexico Regional Vibrio Surveillance System). Illnesses occurred year round, with peaks in spring and autumn. Illnesses lasted a median of 7 days and included fever in half of patients and bloody stools in 25% of patients with relevant information. Seventy-two percent of patients reported no underlying illnesses. In the week before onset, 236 (53%) of 445 patients for whom data were available ate raw oysters, generally at a restaurant or bar. Educational efforts should address the risk of vibrio gastroenteritis for raw oyster consumers, including healthy individuals. Further studies should examine environmental conditions affecting vibrio counts on seafood and processing technologies to enhance the safety of raw oysters.

The pandemic of Salmonella Enteritidis phage type 4 reaches Utah: a complex investigation confirms the need for continuing rigorous control measures.

In 1995, Salmonella Enteritidis (SE) cases in the state of Utah increased fivefold. Isolates were identified as phage type 4 (PT4). Risk factors and sources of infection were investigated in two case-control studies, a traceback of implicated foods, and environmental testing. Forty-three patients with sporadic infections and 86 controls were included in a case-control study of risk factors for infection. A follow-up case-control study of 25 case and 19 control restaurants patronized by case and control patients examined risks associated with restaurant practices. In the first case-control study, restaurant dining was associated with illness (P = 0.002). In the follow-up case-control study, case restaurants were likelier to use > 2000 eggs per week (P < 0.02), to pool eggs (P < 0.05), and to use eggs from cooperative A (P < 0.009). Eggs implicated in separately investigated SE PT4 outbreaks were traced to cooperative A, and SE PT4 was cultured from one of the cooperatives five local farms. We conclude that SE PT4 transmitted by infected eggs from a single farm caused a fivefold increase in human infections in Utah.

Evaluation of safe food-handling instructions on raw meat and poultry products.

Every year in the United States, millions of people become ill, thousands of people die, and substantial economic costs are incurred from foodborne diseases. As a measure to prevent foodborne diseases, since July 1994, the U.S. Department of Agriculture has required that safe food-handling labels be placed on retail packages of raw or partially cooked meat and poultry products. Through selected states Behavioral Risk Factor Surveillance System (BRFSS) interviews, survey data were collected to determine the proportion of adults aware of the label and adults who reported changing their raw meat-handling practices because of the label. Fifty-one percent of the 14,262 respondents reported that they had seen the label. Of these, 79% remembered reading the label, and 37% of persons who reported that they had seen and read the label reported changing their raw meat preparation methods because of the label. Women were more likely than men to have read the label, as were persons who are at least 30 years of age compared to younger adults (P < 0.05). Both label awareness and risky food-handling behaviors increased with education and income, suggesting that safe food-handling labels have limited influence on consumer practices. Our results also suggest that the labels might be more effective in discouraging cross-contamination than in promoting thorough cooking practices. We suggest that the label is only one component among many food safety education programs that are needed to inform consumers about proper food-handling and preparation practices and to motivate persons who have risky food-handling and preparation behaviors to change these behaviors.

Associations Between Diet and Health Behavior: Results from the 1992 Rhode Island Behavioral Risk Factor Survey

The 1992 Rhode Island Behavioral Risk Factor Surveillance System was used to assess self-reported health behaviors of consumers of finfish and raw shellfish. We hypothesized that consumers of finfish, foods considered to be healthy, were more likely than nonconsumers of finfish to partake in health-promoting behaviors. Similarly, we postulated that consumers of raw molluscan shellfish, foods linked to an elevated risk of acquiring various illnesses, were more likely than nonconsumers of raw-shellfish to partake in risk-taking behaviors. Finfish eaters were significantly more likely than abstainers to report recent exercise, efforts to lose weight, periodic monitoring of serum cholesterol, and not currently being smokers. Raw shellfish eaters were significantly more likely than abstainers to report recent acute and chronic alcohol consumption. The results suggest that inquiry into dietary patterns may be an avenue for exploring other health behaviors.

Control strategies for Salmonella enteritidis in five countries

Abstract World Health Organization (WHO) surveillance data on human salmonellosis for 1979–1987 indicate that Salmonella enteritidis (SE) isolation rates are increasing in the Americas and Europe. SE outbreak investigations indicate a strong 3ssociation between the consumption of raw or lightly cooked eggs and human illness. Summaries are presented of programmes to control SE in egg production for five nations: Canada, the Netherlands, Sweden, the UK and the USA. These nations were selected because they had established Salmonella surveillance systems and different rates of SE infection. Although all five nations instituted controls for SE at three principal points in egg production (poultry feed, breeding flocks and egg production), the programmes have distinct characteristics. For context, data obtained from the WHO on reported SE isolates in humans in each of these nations are presented. SE control programmes were influenced by the human isolation rate, government funding and industry support. SE programmes in the five nations are becoming more alike, in that cooperative efforts between government and throughout industry are being promoted. Motivation to establish non-regulatory controls for SE is strengthened by regulatory controls that are available if needed.

Breast-feeding and HIV transmission: Epidemiologic studies and their limitations

Abstract Postnatal human immunodeficiency virus (HIV) transmission from an HIV-infected mother to child has been attributed mostly to breast-feeding. However, the mechanism and timing of HIV transmission via breast-feeding and the risk factors for that mode of transmission are not well defined. A series of case reports and cohort studies have provided useful but incomplete information on the transmission of HIV through breast-feeding. Various studies have yielded risk estimates of 15–40%. The stage of the HIV infection in the mother and the immunologic constituents of the breast milk have been suggested as important determinants of HIV transmission through breast-feeding.