Communicable disease report. CDR review最新文献

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.

Human isolates of multiresistant Salmonella typhimurium definitive phage type (DT) 104 in England and Wales are currently second in number only to those of S. enteritidis phage type 4. Differentiation of strains is essential in epidemiological investigations and the value of one method, plasmid profile typing, has been assessed in a study of 600 isolates of S. typhimurium DT 104 with multiresistant antibiograms (R-types) ACSSuT, ACSSuTCp and ACSSuTTm from humans, food animals, human food, pets, and animal feed made in England and Wales from January 1990 to April 1996. Twenty plasmid profile (PP) types have been identified in isolates of R-type ACSSuT and ACSSuTCp. One profile type, with a single plasmid of 60 megadaltons-PP type A-has predominated, but identification of PP type has proved useful in some epidemiological investigations. A further four PP types have been identified in isolates of DT 104 R-type ACSSuTTm, in which resistance to trimethoprim is encoded by a plasmid of 4.6 megadaltons and the two commonest PP types are related to those also common in DT 104 R-type ACSSuT. Methods of differentiating within the commonest profile type are now needed.

Three thousand and fifty-two infections with opportunist mycobacteria were reported to the PHLS Communicable Disease Surveillance Centre from 1982 to 1994. The commonest reported species was Mycobacterium avium-intracellulare (MAI), followed by M. kansasii and M. malmoense. The annual totals of opportunist mycobacteria increased steadily over this period, mostly, but not exclusively, due to an increase in reports of MAI associated with HIV infection. There were also increases in reports of MAI not associated with HIV infection, and in reports of M. malmoense. The increase in reports of opportunist mycobacteria was seen throughout England and Wales, but underreporting of MAI infection in the National Health Service Thames regions appears to have increased in recent years. Continued referral of isolates of opportunist mycobacteria to one of the PHLS regional centres for mycobacteriology or the Mycobacterium Reference Unit, and reporting to CDSC, is essential for the surveillance of these infections.

An outbreak of Salmonella typhimurium DT104 infection in Shropshire in May 1995 was identified when four isolates were noted to be from members or supporters of a local football team that had held several social functions in the same week. The subsequent investigation identified 16 people with gastrointestinal symptoms and 12 with microbiologically confirmed infection. The outbreak was complex, associated with several social functions on different days, but infection was associated with eating beef at a public house. A number of errors were detected in the cooking, storage, and handling of the implicated food. The investigation identified beef as the vehicle of infection in this outbreak but was unable to show whether it was the original source of infection or whether cross or manual contamination occurred in the kitchen.

Infection with Vero cytotoxin producing Escherichia coli O157 (VTEC O157) is a growing public health problem and the commonest cause of acute renal failure in children in the United Kingdom. Foodborne outbreaks of VTEC O157 infection have been reported in the United Kingdom, other European countries, and North America. Most cases of infection are sporadic, however, and the contribution of food vehicles, animal contact, and person to person spread in the acquisition of infection needs to be clarified. The PHLS is starting a case control study in England to identify and estimate the relative importance of risk factors for the acquisition of VTEC O157 infection. The study will run for 12 months. This article describes its objectives and asks microbiologists, public health physicians, clinicians, and others who may be asked for details about cases or to find suitable controls for their help in achieving a successful outcome.

In the summer of 1995, cryptosporidiosis was diagnosed in a child in hospital. This child had taken part in a summer activity project involving 161 children and nine adults. Reports of a similar illness among a number of other participants prompted an outbreak investigation. A cohort study was conducted in two phases. Thirteen children (aged 6 to 15 years) out of 161 respondents to the first questionnaire met the case definition for illness and cryptosporidium was detected in stools from seven of the 13. Illness was significantly associated with child participants who had visited an open farm (p < .000005). Nine of the cases sought medical attention, and two were admitted to hospital. The second phase of the cohort study was conducted among 52 of the 55 people who had visited the open farm. Illness was significantly associated with playing in sand to which animals had access, at the edge of a stream beside a picnic area (p < .005). Contact with various animals was not associated with illness. This outbreak emphasises the risk for children of visiting open farms. Managers of open farms need to be aware of the potential for transmission of infectious diseases to visiting children. Strict implementation of hygiene measures is essential to minimise risk.

Outbreaks of foodborne viral gastroenteritis in England and Wales from 1992 to 1994 have been analysed using data from the national surveillance scheme for general outbreaks of infectious intestinal disease. The cause was virologically confirmed for 389 (31%) of the 1280 outbreaks for which a minimum set of data were collected. Forty-seven of the 389 were attributed to foodborne transmission, 41 of which were caused by small round structured viruses (SRSV). An infected food handler was suspected to be a contributing factor in 14 and the consumption of oysters in eight of these 41 foodborne SRSV outbreaks. No seasonal pattern emerged. The highest incidences occurred in Wales, West Midlands, and South Western regional health authorities. The annual rate of outbreaks did not increase during the three year period (Chi square for linear trend 0.6; p = 0.4). Much remains to be discovered about the epidemiology of foodborne viruses, and outbreaks present an opportunity to enhance our knowledge. As molecular diagnostic techniques become routinely available, it is likely that the role of viruses in foodborne outbreaks will be increasingly recognised.

Thirty-five people developed gastrointestinal symptoms after a wedding reception attended by 147 guests and served by eight catering staff. A retrospective cohort study showed that illness was associated independently with consumption of a pasta dish and spring rolls. The descriptive epidemiology, obtained from interviews with the guests about foods they had eaten and the onset and duration of symptoms, suggested that the outbreak was likely to have been caused by a small round structured virus (SRSV). No pathogenic bacteria were isolated from cases or samples of food served at the reception. Electron microscopy of three stool specimens revealed no viruses, but SRSV was subsequently identified by reverse transcriptase polymerase chain reaction in one of two stool specimens. Environmental investigation in the kitchen revealed a number of deficiencies.

Two clusters of acute hepatitis B in cardiothoracic surgery patients of two hospitals in the United Kingdom were investigated in 1992 and 1993. The source, a surgeon carrier of hepatitis B virus (HBV) whose serum contained hepatitis B e antigen (HBeAg), was not identified during investigation of the first cluster, although all the health care workers who had performed exposure prone procedures on the infected patients were tested. The HBV status of the surgeon, who was linked epidemiologically and virologically with cases in both clusters, was revealed only during the second investigation, when specimens were obtained directly from the surgeon and the other health care workers involved. Forensic testing showed the blood specimen provided by the surgeon during the first investigation to be distinct from that obtained directly from the surgeon during the second investigation; it later became clear that during the first investigation the surgeon had provided a specimen from a person likely to be hepatitis B surface antigen (HBsAg) negative. Patients on whom the surgeon had performed exposure prone procedures in the 15 months before the surgeon's infectivity was recognised were identified from local records, and those not known to have died or to be resident outside the United Kingdom were subsequently tested for markers of hepatitis B infection at least six months after exposure. In total, 310 of 323 (95%) exposed patients were tested; 20 (6%) were classified as having acquired hepatitis B infection in association with surgery, three of whom developed persistent infection. Two hundred and thirty-nine of the exposed and tested patients had undergone coronary artery replacement surgery with or without heart valve replacement. Thirteen out of 75 (17%) for whom the surgeon had taken the role of first assistant-which usually includes performing sternotomy -became infected, compared with five out of 159 (3%) of those for whom the infected surgeon acted as 'vein harvester' and would have been unlikely to have performed the sternotomy (p = 0.00029). We conclude that patients may be exposed to the blood of at least one operator in as many as one in six cardiothoracic surgery procedures that carry a high exposure risk. We suggest that blood specimens from health care workers should be obtained by directly observed sampling in the investigation of cases of acute hepatitis B infection that may have been acquired during surgery.

Two surgeons (henceforth called A and B) working in neighbouring district general hospitals were found, on routine testing, to carry hepatitis B e antigen and therefore to be at high risk of transmitting infection. Neither surgeon gave a history of injury at work. The only exposure prone operations performed by surgeon A were 16 repairs of uncomplicated inguinal hernias. Two of the 16 patients were found to have acute hepatitis B. In contrast, 15 cases on whom surgeon B performed exposure prone orthopaedic procedures remained free of hepatitis B virus infection. The follow up protocol for the patients of the two surgeons differed in that all surgeon B's patients were immunised using an accelerated course of hepatitis B vaccine, which had not been offered to patients of surgeon A. The detection of two cases of hepatitis B among patients operated on by an infected surgeon illustrates the importance of evaluating the risk of exposure associated with particular procedures when deciding whether to check patients who may have been exposed to a high risk surgeon. Surgeon A had been vaccinated before arriving in the United Kingdom and this incident highlights the need to verify immunity after vaccination against hepatitis B virus.