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Two hundred and twenty-six cases of legionnaires' disease who acquired infection in 1998 have been reported to the PHLS Communicable Disease Surveillance Centre. Twenty-five cases (11%) were reported to have died. One hundred and fifteen cases were associated with travel, either abroad or in the United Kingdom, three cases acquired infection in hospital, and the remaining 108 were presumed to have acquired infection in the community. Thirty-five cases were linked to industrial or community associated outbreaks in England and Wales, 22 cases to outbreaks or clusters abroad, and the remaining 169 cases (75%) were reported as single cases. The proportion of cases diagnosed by detection of urinary antigen has continued to increase; in 1998 it contributed to the diagnosis of 117 cases.

Two hundred and twenty-six residents of England and Wales who developed legionnaires' disease with onset of infection in 1997 were reported to the PHLS Communicable Disease Surveillance Centre. Twenty-eight cases (12%) were reported to have died. Half of the reported cases (114) were associated with travel, either abroad or in the United Kingdom. Six cases acquired infection in hospital and the remaining 106 were presumed to have acquired infection in the community. Nineteen cases were linked to industrial or community associated outbreaks or clusters in England, two cases to a hospital outbreak, and 25 cases to outbreaks or clusters abroad. The remaining 180 cases (80%) were reported as single cases. The proportion of cases diagnosed by detection of urinary antigen has continued to increase. In 1997 this method of diagnosis was included for 60% of confirmed cases and in 46% of all cases.

Two hundred and one cases of legionnaires' disease were reported to the PHLS Communicable Disease Surveillance Centre in 1996. Twenty-four cases (12%) were known to have died. One hundred and one cases were associated with travel, either abroad or in the United Kingdom. Two cases acquired infection in hospital, the smallest number ever reported, and the remaining 98 were presumed to have acquired infection in the community. Fifty-five (27%) of the 201 cases were linked to outbreaks or clusters and the remaining 146 (73%) were reported as single cases. Six outbreaks were associated with industrial premises. Twenty-two of the travel associated cases were part of three travel outbreaks and six clusters. The proportion of cases diagnosed by detection of urinary antigen has continued to increase and in 1996 this method of diagnosis was used for 43% of the cases.

Objectives: To identify the source of an international outbreak of food poisoning due to Salmonella agona phage type 15 and to measure how long the underlying cause persisted., Design: Case-control study of 16 primary household cases and 32 controls of similar age and dietary habit. Packets of the implicated foodstuff manufactured on a range of days were examined for salmonella. All isolates of the epidemic phage type were further characterised by pulsed field gel electrophoresis., Results: 27 cases were identified, of which 26 were in children. The case-control study showed a strong association between infection with S agona phage type 15 and consumption of a peanut flavoured ready to eat kosher savoury snack imported from Israel. S agona phage type 15 was isolated from samples of this snack. The combined food sampling results from the United Kingdom, Canada, the United States, and Israel showed that contaminated snacks were manufactured on at least seven separate dates during a four month period between October 1994 and February 1995. Voluntary recalls of the product successfully interrupted transmission., Conclusions: Rapid international exchanges of information led to the identification of the source of a major outbreak of S agona in Israel and of associated cases in North America. The outbreak showed the value of the Salm-Net surveillance system and its links outside Europe, both for increasing case ascertainment and for improving the information on the duration of the fault at the manufacturing plant.

One hundred and sixty cases of legionnaires' disease were reported to the PHLS Communicable Disease Surveillance Centre in 1995. Twenty cases (13%) were known to have died. Ninety cases (56%) were associated with travel (in the United Kingdom or abroad), four were associated with a stay in hospital, and the remaining 66 were presumed to have acquired infection in the community. One hundred and twenty-three cases (77%) occurred sporadically. Three community outbreaks and one outbreak at an industrial site were detected in England and Wales. One outbreak and five clusters were detected among visitors to Turkey, Spain, and Italy. Seven cases and one outbreak of nonpneumonic legionellosis were also reported. Cases of travel associated legionnaires' disease continue to account for the largest proportion of the total reported in 1995 and the number of hospital acquired cases continues to decline. A cause for concern in 1995 was a fall in the proportion of cases diagnosed by culture of the organism (from 16% in 1994 to only 9% in 1995). This corresponded with a small increase in the proportion of cases diagnosed solely by detection of antigen to L. pneumophila serogroup 1 in urine.

One hundred and sixty cases of legionnaires' disease in England and Wales were reported to the PHLS Communicable Disease Surveillance Centre in 1994, a rate of 3.1 cases per million population. Twenty-seven cases died. Eighty-nine cases (56%) were associated with travel, either in the United Kingdom (UK) or abroad, and six with a stay in hospital; the remaining cases were presumed to have acquired infection in the community. Seven outbreaks were detected in England and Wales: one was associated with a holiday centre, one with a hotel in London, two with industrial sites, and three occurred in the community. A further four clusters were associated with travel abroad: Spain, Ibiza, the Channel Islands, and a Mediterranean cruise. One hundred and twenty-eight of the 160 cases (79%) were sporadic--that is, not known to be associated with outbreaks--43 of which (34%) were not associated with travel nor acquired in hospital.

One hundred and twenty-nine cases of legionnaires' disease were reported in England and Wales in 1993. Twenty-two of the cases died. Sixty-six cases (51%) were associated with travel (in the United Kingdom or abroad), six were associated with a stay in hospital, and the remaining 57 were thought to have acquired infection in the community. Two community and two hospital outbreaks were recognised in England and Wales and four outbreaks were detected in travellers from the United Kingdom to Spain, Greece, and the United States. One hundred and six cases (82%) were not known to have been associated with outbreaks, and 51 (40%) of these were not associated with travel or hospitals.

Two hundred and eighteen nosocomial cases of Legionnaires' disease with 68 deaths were reported to the National Surveillance Scheme for Legionnaires Disease between 1980 and 1992, representing 15% of the reported infections acquired in England and Wales. Twenty-two nosocomial outbreaks accounted for 135 (62%) of these cases, the remainder occurring as single cases either in hospitals where other single cases or outbreaks had been reported in different years or as 'sporadic' cases in hospitals from which no other cases were reported. A clinical history prior to onset of Legionnaires' disease was available for 124 patients, 61 of whom had undergone recent transplant therapy or were immunosuppressed for other reasons. Sixty cases (27%) were diagnosed by culture of the organism and isolates from 56 patients were typed; 25 (42%) were non L. pneumophila serogroup 1 infections. Methods for prevention and control of nosocomial outbreaks are discussed, in particular the susceptibility to Legionnaires' disease of certain groups of hospital patients.

National surveillance of legionnaires' disease in England and Wales identified 588 cases during the years 1979--1982. The majority of cases appeared to be sporadic but 32 clusters of two or more cases were recognised, 24 in association with hotels, seven with hospitals and one with a construction site. Reports (3 published and 3 unpublished) on the investigation and control of six outbreaks are reviewed. All six were found to be common source outbreaks; four hotel associated, one was nosocomial and one was associated with a construction site. Domestic water systems were implicated as sources in the four hotels and the hospital. The most effective control measure was found to be continuous chlorination of the water supply combined with raising the hot water temperature to 60 degrees C or more in the calorifier and at least 55 degrees C to a maximum of 60 degrees C at outlets. Raising hot water temperatures alone was not always completely successful as a control measure. Only in the construction site outbreak was a cooling water system shown to be the principal source of infection.

In January 1984 the River Dee in north Wales was contaminated with phenol, with subsequent contamination of the tap water received by about two million consumers. A retrospective postal survey of 594 households was undertaken to determine whether consumption of this contaminated water was associated with illness. Subjects in areas that received contaminated water reported significantly more gastrointestinal illness than those in a nearby unexposed area (32.6% v 8.7%, p less than 0.00001) as well as reporting a higher incidence of any symptoms (43.6% v 18.4%, p less than 0.00001). Symptoms were consistent with phenol poisoning and bore a strong temporal relation to the pollution of the supply, but they developed at concentrations of phenols previously considered to be safe by the water authorities concerned. Chlorophenols produced during the treatment of water may have aggravated the problem.