Foodborne Snow Mountain agent gastroenteritis with secondary person-to-person spread in a retirement community

A variety of small round-structured viruses are being recognized with increasing frequency as a cause of gastroenteritis in the community, but have rarely been reported to cause outbreaks in hospitals or extended-care facilities. From March 20 through April 15, 1988, an outbreak of gastroenteritis occurred in a retirement facility in the San Francisco Bay area. Illness was characterized by diarrhea, nausea, and vomiting; two residents died. Attack rates were 46% (155 of 336) in residents and 37% (28 of 75) in employees. During the initial outbreak period, illness among residents was associated with two shrimp meals served in the facility dining hall (odds ratio = 6.7). Person-to-person transmission probably occurred: The risk of becoming ill one or two days after a roommate became ill was significantly greater than that of becoming ill at other times during the outbreak (risk ratio = 6.5). Microbiologic examinations for bacterial and parasitic enteric pathogens were negative; however, 27-nm viral particles were detected by immune electron microscopy and by blocking enzyme immunoassay to Snow Mountain agent in stools obtained at the onset of illness from one of six ill residents. Seroconversion (greater than fourfold antibody rise) to Snow Mountain agent was detected in acute- and convalescent-phase serum specimens from five of six ill residents as measured by enzyme immunoassay, but not for Norwalk agent as measured by radioimmunoassay. This report of an outbreak of Snow Mountain agent gastroenteritis in an extended-care facility documents that these difficult-to-identify 27-nm viruses can cause outbreaks in inpatient settings.     

Epidemiologic and laboratory investigation of an outbreak of Campylobacter enteritis associated with raw milk

An outbreak of gastroenteritis occurred in March-April 1981, in Wichita, Kansas, and involved more than 250 persons who drank raw milk from a single local dairy. Campylobacter jejuni was recovered from 60 of 116 (52%) persons in households that had one or more ill family members. A cohort study of families that belonged to a food cooperative that purchased raw milk from the implicated dairy showed a significant association between illness and having drunk raw milk. Thirty-nine of 55 (71%) persons who drank raw milk became ill compared with four of 36 (11%) persons who did not drink raw milk (p less than 0.01, t test, accounting for clustering). Peak (convalescent) antibody titers to C. jejuni, determined by indirect immunofluorescence, in 20 raw-milk drinkers showed a geometric mean of 1:27 in contrast to geometric mean titer of 1:6 in 10 well persons from the cohort who did not drink raw milk (p less than 0.002, t test). C. jejuni was recovered from 21 of 34 (66%) raw-milk drinkers, versus none of 26 people who did not drink raw milk (p less than 0.001, Fisher's exact test, one tailed). C. jejuni of the same serotype was isolated from the case-patients and from rectal swabs of cows in the dairy. These findings indicate that raw milk contaminated by Campylobacter was the vehicle for this outbreak.     

25- to 30-nm virus particle associated with a hospital outbreak of acute gastroenteritis with evidence for airborne transmission

Between November 1 and 22, 1985, an outbreak of acute, nonbacterial gastroenteritis occurred in a 600-bed hospital in Toronto, Ontario, Canada. Illness in 635 of 2,379 (27%) staff was characterized by fatigue, nausea, diarrhea, and vomiting and had a median duration of 24-48 hours. The finding of virus-like particles measuring 25-30 nm in six stool specimens and low rates of seroresponse to Norwalk virus (3/39) and Snow Mountain agent (1/6) suggest that a Norwalk-like virus was responsible for the outbreak. The outbreak was of abrupt onset and high incidence, affecting 79 people in a single day. No common food or water exposure could be identified. The attack rate was greatest (69%) for staff who had worked in the Emergency Room. Of 100 patients and their companions who visited the Emergency Room on November 11-12 for unrelated problems, 33 (33%) developed gastroenteritis 24-48 hours after their visit, versus 0 of 18 who visited the Emergency Room on November 8 (p less than 0.001). An analysis of housekeepers who worked at least once during the period from November 9-13, which included those who became ill during the period of November 9-14, showed that the risk of becoming ill was four times greater for those who visited or walked through the Emergency Room than for those who did not (p = 0.028). These data are consistent with the possibility of the airborne spread of a virus.     

Norwalk-related viral gastroenteritis due to contaminated drinking water

An explosive outbreak of gastrointestinal illness clinically compatible with infection by an agent serologically related to Norwalk virus agent occurred in an elementary school in May 1978. Seroconversion by radioimmunoassay to the Norwalk antigen was noted in two of three ill persons, but no viral particles were identified in stool. Illness developed in 72% of students and teachers at the school, and 32% of household contacts of these ill persons. Of household contacts of persons exposed at school but not clinically ill, 11% developed illness. This value, however, was not statistically different from the level of illness observed concurrently in household contacts of students at an unaffected school nearby. Epidemiologic investigation implicated water as the mode of transmission. Average consumption of one or more glasses per day was strongly associated with illness (p less than 0.00000001). Among soccer team members with limited school contact, water consumption at the school was associated with a 14-fold greater risk of illness (p less than 0.000001). Drinking water was most likely contaminated by back-siphonage through a cross-connection between the school's well and septic tank. This contamination occurred approximately 24 to 36 hours before the outbreak developed.     

Risk factors for secondary transmission in households after a common-source outbreak of Norwalk gastroenteritis

In November 1984, a foodborne outbreak of Norwalk gastroenteritis occurred in a K-12 public school in northern Vermont. The outbreak offered an opportunity to systematically study in detail secondary transmission rates in households. Eating salad at Tuesday's school-sponsored Thanksgiving Banquet was associated with illness among students and staff members (p less than 0.025). Seven of 11 serum pairs from ill persons showed a fourfold or greater rise in antibody titer to Norwalk virus compared with one of nine controls (p = 0.028). The study of secondary household transmission revealed that households with persons with primary illness were 5.5 times more likely to experience secondary illness than households with well school children or adults. As the number of individuals with primary illness in the household increased, the secondary illness rates increased. Pre-school children were twice as likely as adults to develop secondary illness.     

Salmonellosis outbreak on transatlantic flights; foodborne illness on aircraft: 1947-1984

In March 1984, 186 cases of gastroenteritis due to Salmonella enteritidis were reported after 29 flights to the United States on an international airline. An estimated 2,747 passengers on flights to the United States were affected. Illness was associated with flying supersonic or first class (odds ratio = 15, p less than 0.001). Eating food from the first-class menu was associated with illness (p = 0.09), and eating a tourist-class entree was protective (p less than 0.01). In 23 reported outbreaks of foodborne illness on aircraft, Salmonella has been the most common pathogen (seven outbreaks), followed by Staphylococcus (five outbreaks), and Vibrio species (five outbreaks). Outbreaks are most often the result of an improper temperature for preparation or for holding food in the flight kitchens. Serving the flight crew meals from one kitchen carries the risk that the entire crew will become ill.     

An outbreak of gastrointestinal illness associated with the consumption of escolar fish.

An outbreak of gastrointestinal illness occurred amongst attendees of a conference lunch in the Hunter area, New South Wales, in October 2001. A distinctive symptom reported by many ill persons was the presence of oily diarrhoea. The Hunter Public Health Unit investigated the outbreak by conducting a telephone interview of the cohort of conference attendees using a standard questionnaire. Twenty persons out of 44 attendees (46%) became ill following the conference. The median incubation period was 2.5 hours (range 1-90 hours). The most common symptoms reported were; diarrhoea (80%)-38 per cent of these reported oily diarrhoea; abdominal cramps (50%); nausea (45%); headache (35%) and vomiting (25%). For analyses, a case was defined as a person who developed oily diarrhea, or diarrhoea within 48 hours, or had at least two other symptoms of gastroenteritis within 6 hours, of the conference lunch. Seventeen persons had symptoms that met the case definition. None of the foods or beverages consumed were significantly associated with illness, however, all cases had consumed fish and none of those who did not eat fish (4 persons) became ill. Moreover, only 'fish' or 'potato chips' could explain a significant proportion of the illness. Analysis of the oil composition of the fish consumed was consistent with the known profile of the species marketed as 'escolar'. Among those who consumed fish the following potential risk factors did not have a significant association with the illness; Body Mass Index, age, health status and the amount of fish consumed. We concluded that consumption of fish within the marketing group escolar can cause severe abdominal cramping, nausea and vomiting, in addition to incontinent diarrhoea.     

Waterborne Gastroenteritis due to the Norwalk Agent: Clinical and Epidemiologic Investigation

An outbreak of gastroenteritis occurred at a Pennsylvania summer camp in July 1978. Symptoms included abdominal pain (81 per cent), nausea (72 per cent), and vomiting (53 per cent); upper respiratory infection symptoms occurred in 35 per cent of the campers. Illness was associated with consumption of five or more glasses of water or water-containing beverages. Stool cultures from affected persons were negative for bacterial pathogens; however, a fourfold or greater rise to the Norwalk agent was demonstrated in serum samples of three of three ill persons tested and in none of eight controls (p < .02). Campers ill during the first session who were also present during the second session did not become ill during the second session (p < .001). (Am J Public Health 1982; 72:72-74.)     

Relationship between Telework Experience and Presenteeism during COVID-19 Pandemic,United States,March–November 2020

Persons with COVID-19–like illnesses are advised to stay home to reduce the spread of SARS-CoV-2. We assessed relationships between telework experience and COVID-19 illness with work attendance when ill. Adults experiencing fever, cough, or loss of taste or smell who sought healthcare or COVID-19 testing in the United States during March–November 2020 were enrolled. Adults with telework experience before illness were more likely to work at all (onsite or remotely) during illness (87.8%) than those with no telework experience (49.9%) (adjusted odds ratio 5.48, 95% CI 3.40–8.83). COVID-19 case-patients were less likely to work onsite (22.1%) than were persons with other acute respiratory illnesses (37.3%) (adjusted odds ratio 0.36, 95% CI 0.24–0.53). Among COVID-19 case-patients with telework experience, only 6.5% worked onsite during illness. Telework experience before illness gave mildly ill workers the option to work and improved compliance with public health recommendations to stay home during illness.     

Internalizing stigma associated with mental illness: findings from a general population survey in Jamaica.

OBJECTIVES: The culture of stigma associated with mental illness is particularly intense when persons who are normally victims of that stigmatization (mentally ill persons and their family members) themselves act negatively toward others whom they associate with mental illness. We attempt to determine the extent of this internalization and assimilation of stigmatizing attitudes, cognitions, and behaviors in persons who are at risk for such stigmatization in Jamaica. METHODS: Data from a 2006 national survey on mental health were analyzed. Demographic variables, the presence or absence of mental illness in respondents and in their family members, and responses pertaining to behaviors and attitudes toward mentally ill persons were examined. Subsamples (respondents with mental illness, respondents with a family member with mental illness, respondents with neither) were compared using the chi-square test. RESULTS: Respondents with family members with mental illness were less likely to demonstrate a number of different manifestations of stigmatization than others (P=0.009-0.019). Respondents with mental illness showed no difference in the demonstration of a number of different manifestations of stigmatization from other respondents (P=0.069-0.515). CONCLUSIONS: The small number of mentally ill respondents resulted in low statistical power for demonstrating differences between that subgroup and other respondents. The significantly more positive attitudes and behavior of respondents with family members with mental illness suggest that some benefit may be gained by creating more opportunities for the general public to interact with persons with mental illness.     

An outbreak of shigellosis at an outdoor music festival

In August 1988, an estimated 3,175 women who attended a 5-day outdoor music festival in Michigan became ill with gastroenteritis caused by Shigella sonnei. Onset of illness peaked 2 days after the festival ended, and patients were spread throughout the United States by the time the outbreak was recognized. An uncooked tofu salad served on the last day was implicated as the outbreak vehicle (odds ratio = 3.4, p less than 0.0001). Over 2,000 volunteer food handlers prepared the communal meals served during the festival. This large foodborne outbreak had been heralded by a smaller outbreak of shigellosis among staff shortly before the festival began and by continued transmission of shigellosis from staff to attendees during the festival. S. sonnei isolated from women who became ill before, during, and after the festival had identical antimicrobial susceptibility patterns and plasmid profiles. Limited access to soap and running water for handwashing was one of the few sanitary deficits noted at this gathering. This investigation demonstrates the need for surveillance and prompt public health intervention when Shigella infections are recognized in persons attending mass outdoor gatherings, the singular importance of handwashing in reducing secondary transmission of shigellosis, and the potential for explosive outbreaks when communal meals are prepared by large numbers of food handlers.     

Effect of minor illness on serum cholesterol level.

To ascertain the impact of minor illness on total plasma cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C), we analyzed data collected on 6,880 persons examined for the Stanford Five-City Project. Overall, 8.4% of the population reported having a minor illness on the day of examination, although there were substantial variations in minor illness rates with season, city, and year of data collection. After adjustment for age, sex, body mass index, season, and city of residence, we found that those who reported minor illness at the time of examination had a lower mean TC than those who were well (195.9 mg/dL versus 201.2 mg/dL, P less than .005). HDL-C was 51.2 mg/dL in persons with minor illness, and 52.3 mg/dL in persons without (P = .13). Dietary recall data covering the 24-hour period before the examination was available on a subset of the patients. No dietary differences appeared between individuals who reported minor illness and those who did not. In a subset of 162 persons with a minor illness who were followed longitudinally for up to six years, TC adjusted for age was 191.8 mg/dL with minor illness and 196.1 mg/dL without, a difference that was not statistically significant. The results of this study imply that minor illness may contribute to some of the biological variability of TC and HDL-C. Although small, a differential rate of minor illness may sometimes significantly affect interpretation of TC epidemiological and intervention studies or the timing of measurements in clinical practice.     

Norwalk virus gastroenteritis following raw oyster consumption

In January, 1980, six out of 13 persons (46%) attending a party in a small northwest Florida town near the Gulf of Mexico became ill with Norwalk virus gastroenteritis after eating raw oysters. Symptoms experienced by the ill persons were principally nausea (100%), vomiting (83%) and diarrhea (50%) and were of brief duration. The symptom complex and epidemiology of Norwalk virus infection closely resemble the gastrointestinal illness commonly referred to as the 24-hour intestinal flu or "stomach flu." Norwalk virus infection was identified in this outbreak by application of a recently developed sensitive and specific serologic radioimmunoassay. Oysters from the incriminated batch had fecal coliform levels above recommended standards; however, recent studies of oyster-harvesting waters have shown only a weak correlation between fecal coliforms and the presence of enteric viruses. Further studies are needed to determine whether modifications of monitoring modalities for oyster-harvesting waters are needed.     

Study of the method of transmission in an epidemic of gastroenteritis in an extended care service, Florida, 1989]

In January 1989 and outbreak of gastroenteritis (GE) occurred among the residents and the employees of the Extended Care Unit (ECU) of a Florida hospital. There were 14 cases (38.9%) among the 36 ECU patients and 10 (19.2%) among the 52 employees. The illness was characterized by watery diarrhea, fever, abdominal cramps and headache. Bacterial and viral investigations were negative. The incidence density rate of GE for patients in double occupancy room was nine times greater one to three days after a roommate had been ill than at any other time during the outbreak (p = 0.02). Patients who received higher level of nursing and medical care were five times more likely to develop GE than the other patients (p = 0.054). Health workers who reported contact with symptomatic patients were 2.5 times more likely to become cases than the other workers (p = 0.3). These data suggest that the infection was transmitted from patient to patient by contact with health care workers.     

Incidence of gastroenteritis in Norway--a population-based survey

In 1999-2000 we conducted a one-year, retrospective population-based survey in Norway to estimate the incidence of gastroenteritis and study the association with selected exposures. A self-administered questionnaire was mailed to 3000 persons selected at random from the population registry, with 250 persons being contacted each month. The response rate was 61%. The incidence of acute gastroenteritis was 1.2 per person-year. The incidence was higher for women than for men. Of the total of 171 cases, 29 (17%) consulted a physician, 13 (8%) reported that a stool sample was taken, and 7 (4%) were admitted to hospital. Among children aged less than 15 years, drinking water from a private water supply was associated with illness, while using chlorinated water was protective. Among adults aged 20-40 years, travelling abroad was associated with illness. The incidence in our survey is similar to rates found by FoodNet in United States.     

Outbreak of Norwalk virus in a Caribbean island resort: application of molecular diagnostics to ascertain the vehicle of infection

In 1998, an outbreak of gastroenteritis affected at least 448 persons including 122 staff at a resort hotel in Bermuda. A survey among staff indicated that gastroenteritis was associated with eating or drinking at the hotel (OR = 60, 95% CI = 2.4-15.1). Multiple specimens of drinking water had elevated faecal coliform levels and Escherichia coli present, suggestive of faecal contamination. Stools from 18 of the 19 persons with gastroenteritis that were tested were positive for genogroup-II Norwalk-like viruses (NLVs). RT-PCR analysis of a 31 specimen of water produced a genogroup-II NLV genome with a sequence identical to that of NLVs in the stools of three ill persons. This outbreak shows the value of new molecular diagnostics to link illness with a contaminated source through the use of sequence analysis. The risk of outbreaks such as these could be reduced in tourism dependent regions like Bermuda and the Caribbean by regular evaluation of data from the inspection and monitoring of drinking water supplies and waste water systems, by ensuring the chlorination of supplemental drinking water supplies and by establishing food-safety initiatives.     

Viral agents of gastroenteritis. Public health importance and outbreak management

Each year, infectious gastroenteritis causes greater than 210,000 children in the United States to be hospitalized and 4-10 million children to die worldwide. Since the mid-1970s, knowledge has increased dramatically concerning the viral agents that are responsible for much of this public health burden. Rotavirus, the most common cause of diarrhea among children, infects virtually every child in the United States by the age of 4 years and causes potentially lethal dehydration in 0.75% of children less than 2 years of age. Other recently identified pathogens include the enteric adenoviruses, calicivirus, astrovirus, and the Norwalk family of agents. Conclusive diagnosis of these viruses requires electron microscopic examination of stool specimens, a laboratory technique that is available only at a few large centers, including CDC. Stool samples from an outbreak that are submitted to CDC for detection of viral pathology should be collected in bulk from 10 ill persons during their first 48 hours of illness, while feces are still liquid, and should be stored at 4 C (not frozen). Acute- and convalescent-phase serum samples should be collected from the same persons, plus from an equal number of controls, during the first week of illness and 3 weeks thereafter. Control measures for outbreaks of viral gastroenteritis should focus on the removal of an ongoing common source of infection (e.g., an ill food handler or the contamination of a water supply) and on the interruption of person-to-person transmission that can perpetuate an outbreak in a population after the common source has been removed. Because improvements in environmental hygiene may not be accompanied by reductions of endemic diarrhea caused by viruses, immunization may play an important role in future control; vaccine trials for rotavirus are in progress. In anticipation of vaccine development and use, CDC recently began national surveillance for the viral agents of gastroenteritis. Health-care facilities involved in the detection of rotavirus or the other viral agents of diarrhea can participate.     

A foodborne outbreak of gastroenteritis involving two different pathogens.

On the evening of October 10, 1990, many of the 474 inmates of a state prison in Florida began to experience symptoms of gastroenteritis. An investigation included interviews with inmates, evaluation of the kitchen and food-handling practices, cultures of leftover food, stool cultures, and cultures from the nares and skin lesions of food handlers. Of the 331 inmates interviewed, 215 (65%) had diarrhea, vomiting, or both. The median incubation period was 5 hours (range, 1-41 hours). Cases with onset of illness 8 or more hours after the evening meal were more likely than those with earlier onset to have had only diarrhea without vomiting (p < 0.001). Eating turkey at the evening meal on October 10 was associated with risk of illness (relative risk = 4.8, 95% confidence interval 1.7-13.7). Cases who became ill within 8 hours of the evening meal and those who became ill later were both more likely to have eaten turkey than those who did not become ill (p < 0.001 and p < 0.007, respectively). Salmonella infantis and enterotoxin-producing Staphylococcus aureus were both isolated from samples of leftover turkey, and S. infantis was isolated from 18 of 20 stool specimens. Cultures of the anterior nares and skin lesions of food handlers grew S. aureus, but phage typing failed to link these strains to the outbreak. Improper food-handling practices contributed to the development of this outbreak. This report highlights the importance of recognizing multiple-organism outbreaks, since the authors' recommendations for prevention of more cases depended upon knowing the risks associated with the distinct organisms and the possible sources of contamination.     

Norwalk virus gastroenteritis. An outbreak associated with a cafeteria at a college

An explosive outbreak of gastrointestinal illness occurred among students and employees at a small college in Florida in November 1980. Common symptoms were diarrhea, nausea, weakness, abdominal cramps, chills, vomiting, and low-grade fever. Cases of illness were identified in 40% of 628 students and 15% of 162 employees who responded to a survey. Among students, there was a sevenfold excess risk associated with eating one or more meals at the campus cafeteria November 3-5 (p much less than 0.001). Tossed salad from one meal was strongly associated with illness (p less than 0.0001). Fecal contamination of the salad was documented, although the source of contamination was not identified. Person-to-person spread could not be demonstrated. Seroconversion to Norwalk antigen occurred in significantly more cases (5/6) than noncases (1/6) (p = 0.04).     

Person-to-person transmission in an outbreak of enteroinvasive Escherichia coli

In the summer of 1981, an outbreak of diarrhea occurred in students and staff at a school for mentally retarded adults and children in Columbia, Missouri. Forty-one (48%) of 86 students and 38 (28%) of 137 staff members in the two dormitories with the lowest functioning students were ill. Enteroinvasive Escherichia coli 0124:H30 was isolated from 20 persons including six staff members, 13 students, and the ill mother of one of the students. Contact with students was associated with illness. Thirty-eight (33%) of the 115 student-care staff members and none of the 22 nonstudent-care staff members who worked in the two dormitories were ill (p = 0.004, chi-square). In the dormitory with the most dependent students, illness in student-care staff was associated with the number of contacts with ill students and with having taken a student home during the outbreak. Control measures to interrupt transmission included separation of symptomatic or culture-positive students from those who were well, and emphasizing handwashing. The authors present these findings as the first report of person-to-person transmission in an outbreak of enteroinvasive E. coli.