An outbreak of gastroenteritis in a psycho-geriatric hospital associated with a small round structured virus

An outbreak of gastroenteritis in a psycho-geriatric hospital is described. Small round structured viruses, morphologically similar to Norwalk agent, were seen in stool samples from four patients. Although the illness was mild, 67 patients and 30 nurses on four wards were affected over a period of 4 weeks. Because of shortage of staff and isolation facilities, difficulty was experienced in introducing effective control measures.     

Transmission of a small round structured virus by vomiting during a hospital outbreak of gastroenteritis

An outbreak of gastroenteritis due to a small round structured virus (SRSV) (Norwalk-like virus) occurred in an elderly care unit, affecting a total of 126 patients and staff. The outbreak caused major disruption to the provision of health care services by the unit over a 3-week period. Following the outbreak a study was undertaken to explore risk factors for acquisition of SRSV infection by health care workers on the unit. Exposure to patients nearby who were vomiting and the number of close contacts with ill patients were significantly related to the risk of developing gastroenteritis (P < 0·05). No significant increase in risk of developing gastroenteritis was found in nurses who cleaned vomit or faeces from affected patients. The findings suggest that aerosolization of vomit was of major importance in transmission of infection during the outbreak; the implications for infection control are discussed.     

Practical lessons from the management of an outbreak of small round structured virus (Norwalk-like virus) gastroenteritis

An outbreak of viral gastroenteritis caused illness in 92 people during October 2000. All the cases had an association with one hotel and 80% of cases identified had attended one of two buffet meals on 18th October 2000. Cohort analysis did not implicate any particular foodstuff in this outbreak. All bacteriological tests on food samples were negative. Small round structured virus (SRSV)/Norwalk-like virus (NLV) particles were seen by electron microscopy in 6 out of 27 stool samples submitted for analysis. This paper describes the outbreak and in particular the lessons learned from the management and control of it. These include practical points with regard to the outbreak control team, liaison with the microbiology laboratory, handling data, agreeing a case definition, and occupational health issues. All can be applied elsewhere by those responsible for managing outbreaks at a local level.     

Possible community immunity to small round structured virus gastroenteritis in a rural aboriginal community

In April 1998 an outbreak of gastroenteritis affected visitors, but none of the Aboriginal residents, at a Territory Health Services luncheon in a rural Aboriginal community in Central Australia. The epidemiological features and identification of Small Round Structured Virus (SRSV) from two participants suggest that this was an outbreak caused by a SRSV. The attack rate in the visitors who ate or drank food at the luncheon was 73% (11 of 15). Seventeen Aboriginal residents were interviewed, none had gastroenteritis. The community potable water supply was contaminated with faecal bacteria around the time of the outbreak. No particular food could be implicated and laboratory examination of foods was not possible. It is proposed that past exposure to SRSVs may have resulted in the Aboriginal residents developing clinical immunity to infection. The process and consequences of the investigation in this community are also discussed.     

Acute gastroenteritis among schoolchildren associated with reovirus-like agent.

During early summer 1975 and spring 1976, outbreaks of acute gastroenteritis were reported from primary schools and other institutions in several districts of Japan. Outbreaks occurred in an explosive manner resembling mass food poisoning from a school lunch. The majority of patients were in the age group 6-14 years. Clinical features were generally mild, consisting of vomiting and/or diarrhea, often with low-grade fever. Reovirus-like agents in the feces were found in 27 (44%) of 62 patients. The virus found in feces of schoolchildren with acute gastroenteritis (SCGV) was related morphologically as well as serologically, not only to the agent found in infantile gastroenteritis (IGV), but also to neonatal calf diarrhea virus (NCDV). A slight difference in antigenicity between SCGV and IGV as suggested by cross complement fixation (CF) remains to be elucidated. About one-half of paired sera from 54 patients showed a significant rise in CF antibody against SCGV and/or NCDV. The pattern of neutralizing (NT) antibody against NCDV in patients' sera was similar to that of CF antibody. Most children studied had a titer of 1:4 or greater of CF and/or NT antibodies to SCGV and NCDV in acute sera. The relationship between acute gastroenteritis associated with reovirus-like agent in infants and that in schoolchildren is discussed.     

A waterborne outbreak of small round structured virus, campylobacter and shigella co-infections in La Neuveville, Switzerland, 1998

An outbreak of gastro-enteritis occurred in La Neuveville, township with 3358 inhabitants. A retrospective cohort study of 1915 participants showed that 1607 (84%) had been ill. Campylobacter jejuni was isolated from 28 patient faecal samples, Shigella sonnei from 21 patients and small round structured viruses (SRSV) from 6 patients. More than one pathogen was identified in eight persons. The epidemic curve was characteristic of a point-source outbreak. The risk for illness was significantly higher among persons who had drank unboiled drinking water than among those who had not (1290 [80.3%] of 1607 vs. 86 [27.9%] of 308; RR = 2.87; 95% CI 2.40-3.45). Risk increased significantly with the quantity of water consumed (P < 0.00 x 10(-6)). An SRSV isolate from water and one human faeces had an identical DNA sequence. The outbreak was due to a pump failure producing a spill of sewage into the groundwater. We conclude that transmission was waterborne and that measures including early warning, basic hygiene and sanitation improvements controlled this epidemic.     

A large hotel outbreak of Norwalk-like virus gastroenteritis among three groups of guests and hotel employees in Virginia

A large outbreak of acute gastroenteritis occurred among three different groups of guests and the employees of a Virginia hotel within a 2-week period in November 2000. At least 76 of the hotel's guests and 40 hotel employees had acute gastroenteritis during this period. All tested ill persons were infected with the same strain of Norwalk-like virus, as shown by cloning and sequencing of virus detected in stool specimens from the three guest groups and the employees. Epidemiologic investigation suggested food as the probable source for the guests. Most of the employees, including those sick, did not eat in the hotel, suggesting that environmental contamination and person-to-person transmission could have contributed to the outbreak. The disease continued to spread in the hotel, passing from one guest group to another, by food, environmental contamination, and/or by person-to-person transmission through infected employees and guests. The study describes procedures implemented to control the outbreak and makes recommendations for future outbreak control.     

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).     

An outbreak of food-borne gastroenteritis in two hospitals associated with a Norwalk-like virus.

Two connected outbreaks of gastroenteritis in separate hospitals associated with a small round structured virus morphologically indistinguishable from the Norwalk virus are described. The virus was most probably introduced on chicken sandwiches prepared by a member of the kitchen staff who was incubating the disease.     

A large outbreak of Shigella sonnei gastroenteritis associated with consumption of fresh pasteurised milk cheese

A large outbreak of Shigella sonnei gastroenteritis occurred in Murcia Region (Southeast Spain) in the winter of 1995–1996. More than 200 people were affected. Epidemiological investigations implicated a regionally manufactured fresh pasteurised milk cheese as the vehicle of infection. A case–control study showed a statistically significant association between the illness and consumption of the suspect cheese. The dispersed sale of the cheese resulted in a regional dissemination of the organism and people were affected in eight townships. Research suggested that an infected foodhandler at the cheese factory might have been the source of contamination and that the processing method might have allowed cross-contamination to occur. This study emphasises the importance of increasing the control of strict hygiene during the processing of fresh cheese, since legislation does not forbid direct contact by hand that could result in contamination of cheese even when the milk pasteurisation process was correctly performed.     

A gastroenteritis outbreak due to norovirus associated with a Colorado hotel

Describing the system components of norovirus outbreaks is important in understanding how to prevent future outbreaks. Investigation of these components includes environmental, epidemiologic, and laboratory perspectives. This study describes how an investigation from these three perspectives was conducted and the significance of each component in understanding norovirus outbreaks. On May 23, 2000, members of a professional group attending two meetings at a local hotel in Englewood, Colorado, began to complain of gastrointestinal illness. Sixty-nine illnesses were reported among 133 attendees. Eight hotel employees also complained of illness. Staff from the Tri-County Health Department and the Centers for Disease Control and Prevention investigated the outbreak. Three stool specimens collected from ill attendees contained norovirus. While the epidemiologic component did not identify a specific vehicle of transmission, the environmental investigation revealed food-handling practices, food handler perceptions, and hotel policies that may have contributed to disease transmission.     

A large-scale gastroenteritis outbreak associated with Norovirus in nursing homes

An increase in gastroenteritis outbreaks due to Norovirus has been reported worldwide. We investigated a large-scale outbreak affecting 246 residents and 33 staff members in six nursing homes in the Tel-Aviv district, Israel, during 3 weeks in 2002. Person-to-person spread was noticed in all nursing homes. The spread of disease could not be attributed to social interactions. Among the elderly residents, the hospitalization rate was 10.2% and the case-fatality rate was 2.0%. Bacteriological cultures were negative. Overall, 7 out of 15 stool specimens were positive for Norovirus by RT-PCR. All were sequenced and found to be 90% identical. The characteristics of this outbreak and the RT-PCR results suggest that illness was caused by Norovirus. Due to the high case-fatality rate of Norovirus gastroenteritis, there should be a high index of suspicion when encountering a gastroenteritis outbreak among the elderly. This will enable prompt action to stop the spread of illness.     

Antibody responses after repeated influenza A virus immunizations among schoolchildren in Japan.

Antibody responses to influenza virus immunizations were examined among junior high school students. The students received two doses of a commercial split-product vaccine containing influenza A H1N1 during a 2-year period following the first appearance of H1N1 virus in the winter of 1977-78. In haemagglutination-inhibition (HI) tests, the students who had been infected with H1N1 virus in 1977-78 showed a better response and wider cross-reactivity to the drift strain than the students who had not experienced earlier H1N1 influenza infection. Neuraminidase-inhibition (NAI) antibody titres after immunization depended upon a history of natural infection with H1N1 virus, since students not previously infected showed no significant NAI antibody rise after immunization.     

Poor mental health associated with job dissatisfaction among school teachers in Japan

School teaching is regarded as a stressful occupation. The present study aimed to compare the likelihood of having minor psychiatric disorders (MPD) among school teachers with that among civil servants, and to investigate what factors were specifically associated with MPD in teachers. We conducted a questionnaire-based survey of 403 teachers employed at state schools and 611 civil servants as a comparison group in a medium-sized city in Japan. The response rate was 59.6% for teachers and 62.0% for civil servants. Mental health was assessed using the 28-item General Health Questionnaire (GHQ-28), according to which those with a score of six or higher were considered to have MPD. Logistic regression analysis was used to identify the factors associated with MPD. Although the proportion of subjects with MPD among teachers was greater than that among civil servants, the difference in the proportion was not statistically significant in the multiple logistic regression analysis adjusted for potential confounders. In a separate analysis of the teachers, reduced job satisfaction and shorter time spent of leisure were significantly associated with an increased likelihood of having MPD. In the group of civil servants, longer working hours, reduced life satisfaction, a history of sick leave, and physical illness were associated with an increased likelihood of having MPD. When this analysis was conducted separately for male and female teachers, job dissatisfaction alone was associated with MPD only in female teachers. Poor mental health of Japanese school teachers, female teachers in particular, was found to be associated with job dissatisfaction.