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Catering businesses continue to be the most common setting for foodborne disease outbreaks. In a study of catering businesses in England and Wales, operational practices relating to the supply, preparation, and service of food in 88 businesses associated with outbreaks were compared with those practices at 88 control businesses. Operational practices did not differ significantly between case and control businesses but larger small medium-size enterprise (SME) businesses were more likely to be associated with foodborne disease outbreaks than were micro-SME businesses. Businesses associated with outbreaks of Salmonella infection were less likely to use local or national suppliers but instead used regional suppliers, especially for eggs. This practice was the only significantly independent operational practice associated with outbreaks of Salmonella infection. Regional egg suppliers also were more likely to be used by businesses associated with outbreaks attributed to food vehicles containing eggs. Businesses associated with egg-associated outbreaks were less likely to use eggs produced under an approved quality assurance scheme, suggesting that the underlying risk associated with using regional suppliers may relate to the use of contaminated eggs.

Despite structured enforcement of food hygiene requirements known to prevent foodborne disease outbreaks, catering businesses continue to be the most common setting for outbreaks in the United Kingdom. In a matched case control study of catering businesses, 148 businesses associated with outbreaks were compared with 148 control businesses. Hazard analysis critical control point systems and/or formal food hygiene training qualifications were not protective. Food hygiene inspection scores were not useful in predicting which catering businesses were associated with outbreaks. Businesses associated with outbreaks were more likely to be larger small and medium-sized enterprises (SMEs) or to serve Chinese cuisine and less likely to have the owner or manager working in the kitchen, but when size of the SME was taken into account these two differences were no longer significant. In larger businesses, case businesses were more likely to be hotels and were more commonly associated with viral foodborne outbreaks, but there was no explanation within the data for this association.

There are several anecdotal accounts of the association between outbreaks of influenza and meningococcal disease. The exceptional increase in the number of cases of meningococcal infection 2 weeks after an influenza A outbreak in England and Wales during November and December, 1989, provided an opportunity to investigate the relation between the two events. Patients with meningococcal disease in December, 1989, were more likely than age-matched controls to show serological evidence of recent influenza A infection (odds ratio 3.9, 95% Cl 1.2-13.9). The most likely explanation for the association is immune suppression induced by influenza A, though a lowering of mucosal resistance to meningococcal invasion may also be a factor. Public health authorities should be aware of the association and should be prepared to alert medical practitioners and the public to the increased risk of meningococcal disease when influenza A outbreaks occur.

A case-control study was carried out to test the hypothesis that the rise in the rate of Campylobacter jejuni infection in the Brigend area of South Wales during May was due to the consumption or handling of milk from bottles that had been attacked by birds. 32 of 36 cases meeting the case definition were interviewed, along with 2 controls per case, matched for age, sex, and area of residence. There were strong associations between campylobacter infection and doorstep delivery of milk bottles, a history of milk bottle attack by birds, milk bottle attack by birds during the week before illness, and consumption of milk from attacked bottles during the week before illness. There was a very strong dose-response relation between frequency of bird attack and illness. Controls with a history of milk bottle attack by birds were more likely than cases to have taken preventive measures against bird attack and consumption of contaminated milk. Although few people witnessed the attacks, the likely culprits are magpies (Pica pica) and jackdaws (Corvus monedula).

Presumed or confirmed ornithosis developed in 15 of 46 veterinary surgeons within 3 weeks of their attending a training course on the supervision of poultry processing plants. A duck processing plant was the probable source of infection. The attack rate in those visiting this plant was 44% (15/34) and the rate in those who had close contact with duck feathers was 1.7 times the rate in the remainder of the group who visited the plant. The incubation period ranged from 6 to 20 days. This is the second outbreak of the duck-associated ornithosis to be recognised in the U.K.

In the summer of 1981 29 patients living in Gwent, South Wales, had Q fever; 20 were diagnosed by routine clinical and laboratory services and 9 were discovered by active case-finding. The date of onset of symptoms spanned a 2-month period. The peak incidence was at the end of June. A case-control study showed an association with one area on the outskirts of Newport. Most patients had no direct contact with farms of farm animals and a common source of infection could not be identified. The most likely explanation of the outbreak was that farm vehicles had disseminated contaminated straw, manure, or dust in the area of Newport adjacent to farmland.

Endocarditis was recorded in 92 (11%) of 839 confirmed Q-fever infections reported for the Communicable Disease Report by laboratories between 1975 and 1981; Q-fever endocarditis accounted for approximately 3% of all cases of endocarditis reported. Two-thirds of the 92 reports were of men, and in both men and women endocarditis affected mainly young and middle-aged adults. Only one-third of Q-fever endocarditis patients were noted to have an underlying heart-valve lesion. There were also 30 reports of chronic Q-fever infection, and in 10 the primary clinical feature was liver disease. The laboratory data do not support the view that Q-fever endocarditis is a rare compilation of Coxiella burnetii infection, and the condition may be considerably underdiagnosed. Joint veterinary and medical investigations should be undertaken to establish the natural history of Coxiella burnetii infection in the U.K. in order to formulate policies for prevention of acute and chronic infection.

Investigation of an outbreak of viral (Norwalk-like) gastroenteritis amongst staff (40 cases), resident guests (over 70 cases), and persons attending functions (54 cases) at one hotel over 8 days suggested that the main vehicle of infection was cold foods prepared by a food handler during and after a mild gastrointestinal illness. He was excreting Norwalk-like virus particles 48 hours after the illness. In addition, ill kitchen staff vomited in the kitchen area and may have contaminated surfaces and stored foods. It is recommended that food handlers should be regarded as potentially infectious until at least 48 hours after clinical recovery from viral gastroenteritis. Stored foods that may have been contaminated should be immediately discarded and areas of the work place which may have been affected should be identified and decontaminated.

An outbreak of gastroenteritis caused by Salmonella typhimurium phage type 10 in a university hall of residence affected 66 students and one member of staff. Results of a questionnaire survey of students suggested that the main wave of (53) cases was due to consumption of contaminated cottage pie, but the remaining cases could best be explained by person-to-person spread of infection. Investigation of the outbreak was greatly assisted by rigorous case finding, the screening of those at risk for symptomless excretors, and the collection of food histories from those who remained well. The possibility of person-to-person spread of salmonella food-poisoning serotypes should be borne in mind when outbreaks are investigated in closed communities such as institutions, families, and ships.

An outbreak of ornithosis in duck workers in the winter of 1979 and spring of 1980 was discovered by the investigation of a cluster of cases in Norfolk. A serological survey showed that 61% of duck workers but only 23% of control poultry workers had chlamydia group antibody titres of greater than or equal to 1:8. Altogether 9% of duck workers in the survey had antibody titres greater than or equal to 1:32 and a clinical illness suggestive of ornithosis. The proportions of seropositive tests and clinical attack rates were highest in workers eviscerating ducks and lowest in farm workers. It is suggested that a clinical history of contact with poultry should be considered relevant in the diagnosis of ornithosis and that clinicians caring for poultry workers should consider the possibility of ornithosis as an occupational disease.

An outbreak of gastroenteritis affecting 234 pupils and 23 staff at a boarding school occurred over a period of 8 weeks. Campylobacter spp. were isolated from pupils and staff, and from two samples of cold water taken from an open-topped storage tank which supplied predominantly unchlorinated water to the main school building. The two isolates from water were of the same serotype. This serotype was the commonest of the three serotypes of Campylobacter jejuni detected in isolates from pupils and staff. There was a highly significant association between consumption of water from the cold water storage tank and reported illness in staff. Attack rates in pupils corresponded closely with the extent of distribution of this water-supply to the main residential houses. Contamination of water by faecal material from birds or bats was the most likely source of infection.

Epidemiological and microbiological investigation of the four outbreaks of Salmonella enteritidis phage type (PT) 4 that occurred in Wales in 1988 implicated foods containing shell eggs from hens as the vehicle of infection. In a case-control study of sporadic cases there was a significant association between infection and egg consumption in the 3 days before illness. These findings provide data to support the warnings from the Departments of Health in the United Kingdom about risks of infection from eating raw or undercooked hens' eggs.

7 of 101 staff within one department of a large office complex had shingles, as diagnosed by a general practitioner, within a three-month period. This incidence was significantly greater than that in the remaining workforce. Varicella-zoster-specific IgM antibody was detected in all 4 cases from whom early convalescent serum samples were obtained but in none of 22 controls. Within the index department there was evidence of clustering in time and by work area. A case/control study showed that a recent preceeding illness might have been a risk factor for shingles in the outbreak cases, but not for sporadic cases in other departments of the same office complex. This outbreak suggests that shingles can be provoked by reexposure to varicella-zoster virus.