In 1997 the first outbreak of Escherichia coli O157[ratio ]H7 infections involving 14 cases occurred in Finland. A case was defined as a resident of Alavus with an episode of diarrhoea between 5 and 17 July 1997, and from whom E. coli O157[ratio ]H7 was isolated from stool. The investigation included case searching and a population-based case control study. Five primary and eight symptomatic secondary cases of E. coli O157[ratio ]H7 illness were detected. In the 10 days before the outbreak, all 5 primary patients (aged 3–8 years), but only 6 of 32 population controls from the same age range (Fisher's test, P<0·001) and 4 of 10 sibling controls (P<0·05) had visited (but had not necessarily bathed in) a shallow beach popular among young children. Four out of 5 primary cases had remained within 5 m of the beach while swimming and had swallowed lake water compared to 1 of 5 population controls. These analytical epidemiologic findings incriminated fresh lake water as the vehicle of E. coli O157[ratio ]H7 transmission.

The purpose of this study was to determine the presence of thermophilic Campylobacter spp. and Salmonella spp. in sand from non-EEC standard and EEC standard designated beaches in different locations in the UK and to assess if potentially pathogenic strains were present. Campylobacter spp. were detected in 82/182 (45%) of sand samples and Salmonella spp. in 10/182 (6%). Campylobacter spp. were isolated from 46/92 (50%) of samples from non-EEC standard beaches and 36/90 (40%) from EEC standard beaches. The prevalence of Campylobacter spp. was greater in wet sand from both types of beaches but, surprisingly, more than 30% of samples from dry sand also contained these organisms. The major pathogenic species C. jejuni and C. coli were more prevalent in sand from non-EEC standard beaches. In contrast, C. lari and urease positive thermophilic campylobacters, which are associated with seagulls and other migratory birds, were more prevalent in sand from EEC standard beaches. Campylobacter isolates were further characterized by biotyping and serotyping, which confirmed that strains known to be of types associated with human infections were frequently found in sand on bathing beaches.

To estimate the incidence of Guillain-Barré syndrome (GBS) following Campylobacter jejuni infection (CI) we studied three populations where outbreaks of CI had occurred involving an estimated 8000 cases. No case of GBS was detected in the 6 months following the outbreaks in the local populations. The point estimate for the risk of GBS following CI estimated in this study was 0 in 8000 (95% confidence interval 0–3).

The plasmid pOG670, a 54 kb, conjugative plasmid that specifies resistance to ampicillin and kanamycin and belonging to the incompatibility group X (IncX), was transferred into 10 isolates of Salmonella enterica serotype Enteritidis belonging to 10 different phage types (PT1, 2, 3, 4, 8, 9, 9b, 10, 11 and 13). Acquisition of the plasmid by these strains did not result in the loss of any resident plasmids but resulted in phage type conversion in 8 of the 10 strains (PT1, 2, 4, 8, 9, 9b, 10 and 11). The observed changes in phage type were found to result from the loss of sensitivity to 3 of the 10 typing phages used (phages 3, 5 and 7). Where the conversion resulted in a change to a defined phage type, both the new and original PTs belonged to the same, previously described, evolutionary lines. Enteritidis PTs 1, 4 and 8, commonly associated with poultry world-wide, were converted to PTs 21, 6 and 13a respectively. The results indicate a different route for phage type conversion Enteritidis from others reported in the literature and, although IncX plasmids are not normally present in PT8 or PT13a, may suggest a possible mechanism/link connecting these phage types.

The influence of consumption of a lactic acid-fermented cereal gruel togwa with pH[les ]4 on the presence of faecal enteric bacteria such as campylobacter, enterohaemorrhagic Escherichia coli (EHEC[ratio ]O157), enterotoxigenic Escherichia coli (ETEC), salmonella and shigella was evaluated. Under 5 years old healthy children listed in an ascending order of age were alternatively assigned and given either a lactic-acid fermented cereal gruel togwa (test diet) or an unfermented cereal gruel uji (control diet) once a day for 13 consecutive days. The presence of the enteropathogens was examined in rectal swabs collected from the children at baseline (before feeding session started), on days 7 and 13, and additionally 14 days (follow-up day) after the feeding session had stopped. The swabs were cultured on to different optimal media for respective enteropathogen and confirmed by standard microbiological and serological methods. Campylobacter spp. dominated among the enteropathogens (62% out of total) followed by Salmonella spp., ETEC and Shigella spp. Children with isolated enteropathogens in the togwa group was significantly reduced (P<0·001) from 27·6% at baseline to 7·8, 8·2 and 12·7% on days 7, 13 and follow-up day, respectively. The effect was more pronounced in those children taking togwa >6 times during the study period. In the control group, there was a slight decrease from 16·7% at baseline to 11·4% on day 7 and 8·1% on day 13. On the follow-up day, enteropathogens were found in 22·6% of the children, which was significantly higher than in those children taking togwa >6 times. We conclude, that regular consumption of togwa with pH[les ]4, once a day, three times a week may help to control intestinal colonization with potential diarrhoea-causing pathogens in young children.

One-hundred-and-thirteen isolates of Salmonella serotype Thompson from diverse sources in seven countries were characterized by PvuII ribotyping and IS200 fingerprinting. Ten PvuII ribotypes were observed. The predominant PvuII ribotype 1 represented a major clone of world-wide distribution but was not found in Australia; PvuII ribotypes 2 and 3 represented minor clones. HincII ribotyping discriminated subtypes within PvuII ribotype 1: HincII ribotype 1 was distributed widely but HincII ribotype 2 was found mainly in Scottish isolates. None of 101 isolates of PvuII ribotypes 1–3 contained copies of IS200. All 12 isolates of PvuII ribotypes 4–10 were from Australia and 7 of them contained copies of IS200 of 5 different profiles. These results suggest the existence of at least two lineages of Salmonella Thompson with a different geographical distribution. The finding that most isolates from man and poultry in Scotland belonged to the same ribotype (PvuII 1/HincII 2) and were IS200-negative suggests that poultry is an important source of human infection in Scotland.

A surveillance system to assess the impact and changing epidemiology of invasive meningococcal disease in Europe was set up in 1987. Since about 1991, contributors from national reference laboratories, national communicable disease surveillance centres and institutes of public health in 35 European countries provided information on all reported cases of meningococcal disease in their country. We describe some trends observed over the period 1993–6. The main findings were: the overall incidence of meningococcal disease was 1·1 per 100000 population but there was some evidence of a slow increase over time and with northern European countries tending to have a higher incidence (Kendall correlation 0·5772, P<0·001), an increasing predominance of serogroup C, and a shift in the age distribution towards teenagers and away from younger children (χ2 test for trend 44·56, P<0·0001), although about half of the cases were under 5 years of age. The overall case fatality rate was 8·3% and the most common serosubtypes were B[ratio ]15[ratio ]P1.7,16 and C[ratio ]2a[ratio ]P1.2,5.

In this 1 year cross-sectional study of personnel being discharged from compulsory military service, an available database of health-related information was used to examine the association of meningococcal carriage with socio-demographic factors. A representative, systematic sample of 1632 personnel was interviewed and had throat cultures taken. The overall meningococcal carriage rate was 16%. Serogroups B and Y accounted for 76% and 13% of the isolates respectively. In univariate analysis, carriage was associated with male gender (P<0·0001), <12 years school education (P=0·002), smoking (P=0·014), and service at a ‘closed’ base, reflecting greater interpersonal contact (P<0·0001). In multivariate analysis, only service on a closed base and male gender retained significance. School education of <12 years remained significant for females only. Variables not associated with carriage included number of siblings, intensity of smoking, and use of the contraceptive pill. In this setting, meningococcal carriage was associated with the type of base on which soldiers served; and smoking was not an independent risk factor for carriage.

Reports of increasing incidence and severity of invasive group A streptococcal (GAS) infections come mainly from affluent populations where exposure to GAS is relatively infrequent. We conducted a 6-year retrospective review of GAS bacteraemia in the Northern Territory of Australia, comparing the Aboriginal population (24% of the study population), who have high rates of other streptococcal infections and sequelae, to the non-Aboriginal population. Of 72 episodes, 44 (61%) were in Aboriginal patients. All 12 cases in children were Aboriginal. Risk factors were implicated in 82% of episodes (91% in adults) and there was no significant difference in the proportion of Aboriginal compared to non-Aboriginal patients with at least one risk factor. Genetic typing of isolates revealed no dominant strains and no evidence of a clone which has been a common cause of these infections elsewhere.

Aboriginal communities in Northern Australia with high rates of group A streptococcal (GAS) skin infection in childhood also have high rates of renal failure in adult life. In a cross-sectional study of one such high risk community, albuminuria was used as a marker of renal disease. The prevalence of albuminuria increased from 0/52 in subjects aged 10–19 years to 10/29 (32·9%) in those aged 50 or more (P<0·001). Antibodies to streptococcal M protein, markers of past GAS infection, were present in 48/52 (92%) at ages 10–19 years, 16/32 (50%) at ages 30–39, and 20/29 (69%) in those aged 50 or more. After allowing for the age-dependencies of albuminuria and of M protein antibodies (P<0·001) albuminuria was significantly associated with M protein antibodies (P<0·01). Thus, 72% of adults aged 30 or more with M protein antibodies also had albuminuria, compared with only 21% of those who were seronegative. More detailed modelling suggested that although most Aboriginal people in this community developed M protein antibodies following GAS infection in childhood, the development of proteinuria was associated with the persistence of such seropositivity into adult life. The models predicted that proteinuria developed at a mean age of 30 years in seropositive persons, at 45 years in seronegative persons who were overweight, and at 62 years in seronegative persons of normal weight. We demonstrated a clear association between evidence of childhood GAS infection and individual risk of proteinuria in adult life. This study provided a strong rationale for prevention of renal disease through the more effective control of GAS skin infections in childhood and through the prevention of obesity in adult life.

During a 1-year period from October 1995 to September 1996, 273 isolations of Streptococcus pneumoniae were made from various types of clinical specimens. The majority of the isolates (39·2%) were from sputum whilst 27·5% were from blood, CSF and other body fluids. The organism was isolated from patients of all age groups, 31·1% from children aged 10 years and below, 64·7% of which come from children aged 2 years or below. The majority of the isolates belong to serotypes 1, 6B, 19B, 19F and 23F. Serotypes 1 and 19B were the most common serotypes associated with invasive infection. About 71·9% of the invasive infections were due to serotypes included in the available 23 valent polysaccharide vaccine. The rates of resistance to penicillin and erythromycin were 7·0 and 1·1% respectively. Our findings show that the serotypes of S. pneumoniae causing most invasive infections in Malaysia are similar to those in other parts of the world and the available vaccine may have a useful role in this population.

A novel water quality intervention that consists of point-of-use water disinfection, safe storage and community education was field tested in Bolivia. A total of 127 households in two periurban communities were randomized into intervention and control groups, surveyed and the intervention was distributed. Monthly water quality testing and weekly diarrhoea surveillance were conducted. Over a 5-month period, intervention households had 44% fewer diarrhoea episodes than control households (P=0·002). Infants <1 year old (P=0·05) and children 5–14 years old (P=0·01) in intervention households had significantly less diarrhoea than control children. Campylobacter was less commonly isolated from intervention than control patients (P=0·02). Stored water in intervention households was less contaminated with Escherichia coli than stored water in control households (P<0·0001). Intervention households exhibited less E. coli contamination of stored water and less diarrhoea than control households. This promising new strategy may have broad applicability for waterborne disease prevention.

The mode of spread of Helicobacter pylori infection is subject to ongoing debate. Recent studies among patients with gastrointestinal disorders suggest a potential role of conjugal transmission. In this study, the clustering of H. pylori infection was assessed among 110 employees of a health insurance company and their partners. Active infection with H. pylori was measured by the 13C-urea breath test. Information on potential confounders was collected by a standardized questionnaire. Overall, 16 employees (14·5%) and 24 partners (21·8%) were infected. While only 7% (6/86) of employees with an uninfected partner were infected, this applied to 42% (10/24) of employees with an infected partner. A very strong relation between partners' infection status persisted after control for age and other potential confounders (adjusted odds ratio, 7·0; 95% confidence interval, 1·8–26·7). Furthermore, the risk of infection increased with the number of years lived with an infected partner. These results support the hypothesis of a major role of spouse-to-spouse transmission of H. pylori infection.

The capture–recapture method was used to estimate the sensitivity of case finding in two national STD surveillance systems: (1) STD registration at municipal health services (STD-MHS); (2) statutory notification by clinicians (NNS). To identify those cases common to both surveillance systems, cases from 1995 were compared using individual identifiers. Estimated sensitivities for syphilis were: STD-MHS 31% (95% CI: 27–35%), NNS 64% (56–71%); and for gonorrhoea: STD-MHS 15% (14–18%), NNS 22% (19–25%). The combined sensitivity of both systems was 76% for syphilis and 34% for gonorrhoea. Differences in the sensitivity of the systems were significant. The NNS was more sensitive than the STD-MHS, and the identification of cases was significantly more sensitive for syphilis than for gonorrhoea. A stratified analysis showed comparable results for the two sexes. Knowledge on the sensitivity of surveillance systems is useful for public health decisions and essential for international comparisons.

An automated early warning system has been developed and used for detecting clusters of human infection with enteric pathogens. The method used requires no specific disease modelling, and has the potential for extension to other epidemiological applications. A compound smoothing technique is used to determine baseline ‘normal’ incidence of disease from past data, and a warning threshold for current data is produced by combining a statistically determined increment from the baseline with a fixed minimum threshold. A retrospective study of salmonella infections over 3 years has been conducted. Over this period, the automated system achieved >90% sensitivity, with a positive predictive value consistently >50%, demonstrating the effectiveness of the combination of statistical and heuristic methods for cluster detection. We suggest that quantitative measurements are of considerable utility in evaluating the performance of such systems.

This cross-sectional study of 400 sera from a randomly selected adult population in Northern Ireland, using a microimmunofluorescence assay, demonstrated high overall seropositivity (70%) for IgG Chlamydia pneumoniae antibodies in developed populations. Seropositivity was shown to be unrelated to gender, age or smoking but there was an inverse trend between infection and educational level achieved as a measure of socio-economic status. IgG levels were also higher during the winter months suggesting seasonal variation of Chlamydia pneumoniae infection. The high prevalence of evidence of exposure to Chlamydia pneumoniae as described in this study may have implications for prevention of cardiovascular disease if further evidence conclusively determines that infection with this organism is a risk factor for cardiovascular disease.

The newly described microorganism ‘Simkania Z’, related to the Chlamydiae, has been shown to be associated with bronchiolitis in infants and community acquired pneumonia in adults. The prevalence of infection in the general population is unknown. A simple ELISA assay for the detection of serum IgG antibodies to ‘Simkania Z’ was used to determine the prevalence of such antibodies in several population samples in southern Israel (the Negev). The groups tested included 94 medical and nursing students, 100 unselected blood donors, 106 adult members of a Negev kibbutz (communal agricultural settlement), and 45 adult Bedouin, residents of the Negev. IgG antibodies to ‘Simkania Z’ were found in 55–80% of these presumably healthy individuals, independently of antibodies to Chlamydia trachomatis and Chlamydia pneumoniae. The Bedouin had a seropositivity rate of 80%, while all other groups had rates of between 55 and 64%. These results indicate that ‘Simkania Z’ infection is probably common in southern Israel.

Confirmed acute hepatitis B infections are reported to the Public Health Laboratory Service Communicable Disease Surveillance Centre by laboratories in England and Wales. These reports have been used to monitor trends in the incidence of hepatitis B virus (HBV) infection over time, and between exposure categories and age groups. Between 1985 and 1996 a total of 9252 cases of acute HBV infection were reported; the number of reports fell from 1761 in 1985 to 581 in 1996. Most infections were reported in adults aged 15–44 years [n=7365 (80%)], and infections were more commonly reported in males [n=6490 (70%)] than females [n=2658 (29%)]. The probable means of acquisiiton was known for just over half of all adult cases [4827/8956 (54%)]. Injecting drug use was the most common exposure [n=1901 (21%)], followed by sex between men and women [n=1140 (13%)] and sex between men [n=1025 (11%)]. The number of infections in injecting drug users fell in the late 1980s, but increased again from 1991 onwards. In children aged under 15 years, infections acquired by mother to baby transmission accounted for 35/170 (21%) of the total. Surveillance indicates that the incidence of acute hepatitis B infection fell in the late 1980s, probably reflecting changed behaviour in injecting drug users. An increase in the number of infections in injecting drug users since 1993 may indicate ongoing transmission that has not been contained by the introduction of needle exchange schemes or by selective vaccination.

Cost effectiveness analyses of alternative hepatitis B vaccination programmes in England and Wales require a robust estimate of the lifetime risk of carriage. To this end, we report the prevalence of infection in 3781 anonymized individuals aged 15–44 years whose sera were submitted in 1996 to 16 microbiology laboratories in England and Wales. One hundred and forty-six individuals (3·9%) were confirmed as anti HBc positive, including 14 chronic carriers (0·37%). The prevalence of infection and carriage was higher in samples collected in London and increased with age. No increased risk of infection was seen in sera from genito-urinary (GUM) clinics. Only 15 sera positive for hepatitis B were also positive for hepatitis C. Our results confirm the low prevalence of hepatitis B in England and Wales, are consistent with previous estimates of carriage and suggest that many infections were acquired while resident outside the UK. Future prevalence studies should determine the country of birth and other risk factors for each individual in order to confirm these findings.

We studied the seroprevalence of hepatitis B virus (HBV), hepatitis C virus (HCV) and GB virus-C (GBV-C) infections in 348 Siberian natives who lived in the Kamchatka Peninsula of Russia. Of 348 samples studied, the seroprevalence of HBsAg and anti-HBs were 11·8% (41 of 348 samples) and 35·9% (125 of 348 samples), respectively. The prevalence of HCV infection was 1·4% (5 of 348 samples), and that of GBV-C RNA, using RT–PCR methods, was 7·5% (26 of 348 samples). In Siberia, the prevalences of HBV and GBV-C infections were about tenfold higher than those in Japan. The prevalence of HBsAg in subjects under 50 years of age was significantly higher than that in those over 50 years old (P<0·05). Because HBV infection is highly endemic in Siberia, we propose that the community-based mass immunization must be conducted as soon as possible in this area.