Foodborne outbreaks of cryptosporidiosis are uncommon. In Denmark human cases are generally infrequently diagnosed. In 2005 an outbreak of diarrhoea affected company employees near Copenhagen. In all 99 employees were reported ill; 13 were positive for Cryptosporidium hominis infection. Two analytical epidemiological studies were performed; an initial case-control study followed by a cohort study using an electronic questionnaire. Disease was associated with eating from the canteen salad bar on one, possibly two, specific weekdays [relative risk 4·1, 95% confidence interval (CI) 2·1–8·3]. Three separate salad bar ingredients were found to be likely sources: peeled whole carrots served in a bowl of water, grated carrots, and red peppers (in multivariate analysis, whole carrots: OR 2·1, 95% CI 1·1–4·0; grated carrots: OR 2·1, 95% CI 1·2–3·9; peppers: OR 3·3, 95% CI 1·7–6·6). We speculate that a person excreting the parasite may have contaminated the salad buffet.

Despite increasing migration, the impact of HIV epidemics from Central and Eastern Europe (C&EE) on the UK HIV epidemic remains small. C&EE-born adults comprised 1·2% of adults newly diagnosed with HIV in the UK between 2000 and 2007. Most C&EE-born women probably acquired their infection heterosexually in C&EE. In contrast, 59% of C&EE-born men reported sex with men, half of whom probably acquired their infection in the UK. Previously undiagnosed HIV prevalence in C&EE-born sexual-health-clinic attendees was low (2007, 0·5%) as was overall HIV prevalence in C&EE-born women giving birth in England (2007, <0·1%). The high proportion of men who have sex with men (MSM) suggests under-reporting of this group in C&EE HIV statistics and/or migration of MSM to the UK. In addition to reducing HIV transmission in injecting drug users, preventative efforts aimed at C&EE-born MSM both within their country of origin and the UK are required.

In the Dutch national vaccination campaign for behavioural risk groups, anti-HBcore is used as the primary HBV screening test. Samples with positive results undergo testing for active infection (HBsAg) but are otherwise accepted as indicating past infection, thereby assuming immunity. This study evaluated evidence for immunity in the target population screened on the basis of this algorithm, by re-analysing 1000 anti-HBcore-positive blood samples equally divided among risk groups: 14·7% of confirmed anti-HBcore lacked anti-HBs (‘isolated’ anti-HBcore). Independent risk factors for isolated anti-HBcore were risk group, HCV infection in hard-drug users (DU) and origin from Sub-Saharan Africa. After extrapolation, the proportion of participants who were said to be immune but lacked any additional evidence of immunity amounted to 9·6% (ranging from 12·5% in DU to 6·5% in men who have sex with men). It is recommended that as a minimum anti-HBs screening is included in testing algorithms used to determine vaccination programmes for risk groups, in particular in DU.

It has been suggested that warm and humid weather is related to a high incidence of Legionnaires' disease (LD), but no data on this association existed in The Netherlands. The objective of this study was to investigate the short-term effects of the weather on LD in The Netherlands. National LD surveillance and meteorological data were obtained. We analysed the data using Poisson regression, adjusting for long-term trends, and using principal components analysis. The highest weekly incidence of LD occurred when the mean weekly temperature was +17·5°C. Mean weekly relative humidity, temperature and precipitation intensity were associated with LD incidence in the multivariable model. Warm, humid and showery summer weather was found to be associated with higher incidence of LD in The Netherlands. These results may be used to predict an increase in the number of cases of LD in The Netherlands during the summer.

Identifying county-level sociodemographic and economic factors associated with the incidence of enteric disease may provide new insights concerning the dynamics of community transmission of these diseases as well as opportunities for prevention. We used data from the National Notifiable Diseases Surveillance System, the U.S. Census Bureau, and the Health Resources and Services Administration to conduct an ecological analysis of 26 sociodemographic and economic factors associated with the incidence of salmonellosis, shigellosis, and E. coli O157:H7 infections in US counties for the period 1993 to 2002. Our study indicates that race, ethnicity, place of residence, age, educational attainment, and poverty may affect the risk of acquiring one of these enteric bacterial diseases. The lack of specificity of information regarding salmonellae and shigellae serotypes may have led to less specific associations between community-level determinants and reported incidence of those diseases. Future ecological analyses should use serotype-specific data on incidence, which may be available from laboratory-based surveillance systems.

The aim was to investigate the impact of the main prognostic factors on HIV evolution. A multi-state Markov model was applied in a cohort of 2126 patients to estimate impact of these factors on patients' clinical and immunological evolutions. Clinical progression and immunological deterioration shared most of their prognostic factors: male gender, intravenous drug use, weight loss, low haemoglobin level (<110 g/l), CD8 cell count (<500/mm3) and HIV viral load (>5 log10 copies/ml). Highly active retroviral therapy reduced the risks of clinical progression and immune deterioration whatever patients' CD4 cell count. Risk reductions were 41–60% for protease inhibitor-based and 27–68% for non-nucleoside reverse transcriptase inhibitor-based regimens. Three-year transition probabilities showed that only patients with a CD4 cell count ⩾350 CD4/mm3 could in most cases maintain their immunity. This model provides ‘real life’ transition probabilities from one immunological stage to another, allowing decision analyses that could help determine the beneficial therapeutic strategies for HIV-infected patients.

Infection with Epstein–Barr virus (EBV) followed by infectious mononucleosis (IM) is now considered to be a risk factor for Hodgkin's disease (HD). It is less clear whether EBV infection and IM are associated with an increased risk of cancer generally. We used a longstanding record-linkage dataset in Oxford (years 1963–1998), and a more recent record-linkage dataset covering England (1999–2005), to compare rate ratios for cancer between people admitted to hospital for IM and a reference cohort. In the Oxford cohort, there was an increased risk of subsequent HD [rate ratio (RR) 6·0, 95% confidence interval (CI) 2·4–12·5] but not of other cancers combined (RR 0·85, 95% CI 0·57–1·23). In the England cohort, there were increased risks of HD (RR 3·2, 95% CI 1·2–7·0), non-Hodgkin's lymphoma (RR 5·6, 95% CI 2·9–9·8), and oropharyngeal cancer (RR 5·4, 95% CI 1·1–16·2), but no significant overall risk of cancer when lymphomas were excluded (RR 1·01, 95% CI 0·71–1·41). We confirm an association between IM and lymphoma; but the risk, if any, of cancer more generally is likely to be small.

A 12-month abattoir study was undertaken from January 2003. We collected 7492 intestinal samples from cattle, sheep and pigs at slaughter. Rectal samples were taken from cattle and sheep and caecal samples from pigs. They were examined for verocytotoxigenic E. coli (VTEC) O157, Salmonella, thermophilic Campylobacter and Yersinia enterocolitica. Data were collected on the animal from which the sample came and this information was analysed to look at potential risk factors for carriage of these organisms. Logistic regression models were run where an adequate number of positive results were available. This revealed that VTEC O157 carriage in cattle was associated with the summer period and that age was a protective factor. Salmonella carriage in pigs was associated with lairage times >12 h, the North East and not feeding when there was no bedding available. In cattle, carriage was associated with the summer period, the Eastern region of GB and dairy animals. In sheep a spring seasonal effect was seen, which coincided with the lambing period. The carriage of thermophilic Campylobacter in cattle was associated with single-species abattoirs, with age a protective factor. In sheep, winter was a risk period with lairage management influential. For pigs, lairage times of <12 h were found to be associated with carriage. A seasonal trend for carriage of Y. enterocolitica in all species was demonstrated with the period December–May a risk. For cattle, age was also a risk factor; for sheep feeding in the lairage and for pigs being held overnight were risk factors.

Surveillance for gastroenteritis rarely detects small, intra-familial outbreaks. This study examined intra-household transmission of gastroenteritis using prospectively collected data from 2811 participants (600 households) in a community-based study. There were 258 household clusters of gastroenteritis during the 15 months of observation involving 774 residents (28% of total). Age <6 years and attendance at a day care/kindergarten were associated with increased likelihood of inclusion in a cluster. The reach of illness into the household was extensive, with 63% of household members affected by symptoms during clusters. Simultaneous and secondary transmission of gastroenteritis appeared equally common. In only 20% of clusters did more than one member submit a faecal specimen. Of clusters where two or more specimens were submitted, concordance in laboratory confirmation of pathogens was 18·8%. Our results show that clustering of gastrointestinal symptoms within households occurs commonly, but reliance on pathogen notification data will substantially underestimate the true frequency of gastroenteritis clusters.

This study was undertaken to detect Trypanosoma evansi infection in clinically ill cattle, buffaloes and horses that were suspected of ‘surra’ infection. Various diagnostic tests were utilized in order to assess the prevalence of infection in the clinically ill and ‘suspected’ animals. Animals in the Eastern Region of India were systematically studied for T. evansi infection, which had not been tested for previously. Examination of Giemsa-stained blood smears detected 5·3%, 9·4% and 40·6% infections; the mouse inoculation test detected 18·4%, 15·6% and 46·9% infections whereas an in-house ELISA detected anti-trypanosomal antibodies in 42·1%, 43·8% and 65·6% infections in clinically ill buffaloes, cattle and horses, respectively. It can be concluded that T. evansi is prevalent in cattle, buffaloes and horses in the Eastern Region of India.

We determined the genetic relationships and origin of the dengue virus (DENV) responsible for an outbreak of dengue fever (DF) in Guangdong province, China, in 2006. Five DENV type 1 (DENV-1) isolates were obtained from human serum samples collected from DF patients during the outbreak. The nucleotide sequences of the E (envelope) gene were compared with those of 48 previous DENV-1 isolates: 18 from Guangdong province, one from Fujian province, one from Zhejiang province, and 28 from other countries in the South Asian region. The results suggested that four DENV-1 isolates identified in Guangdong province in 2006 might be in general circulation there, although these DENV-1 viruses may have been originally introduced into the province from other countries. In contrast, one isolate from Guangzhou city in 2006, may have been introduced by a recently imported case from Cambodia.

The cytopathogenicity of 22 Legionella pneumophila isolates from 17 hospitals was determined by assessing the dose of bacteria necessary to produce 50% cytopathic effect (CPED50) in U937 human-derived macrophages. All isolates were able to infect and grow in macrophage-like cells (range log10 CPED50: 2·67–6·73 c.f.u./ml). Five groups were established and related to the serogroup, the number of PFGE patterns coexisting in the same hospital water distribution system, and the possible reporting of hospital-acquired Legionnaires' disease cases. L. pneumophila serogroup 1 isolates had the highest cytopathogenicity (P=0·003). Moreover, a trend to more cytopathogenic groups (groups 1–3) in hospitals with more than one PFGE pattern of L. pneumophila in the water distribution system (60% vs. 17%) and in hospitals reporting cases of hospital-acquired Legionnaires' disease (36·3% vs. 16·6%) was observed. We conclude that the cytopathogenicty of environmental L. pneumophila should be taken into account in evaluating the risk of a contaminated water reservoir in a hospital and hospital acquisition of Legionnaires' disease.

The impact of hepatitis B vaccination in men having sex with men in Amsterdam has been marginal until now, possibly because of increases in sexual risk behaviour counterbalancing the effect of vaccination. A mathematical model is used to describe the hepatitis B epidemic. The model shows that, with the current vaccination coverage, the decrease in incidence is small in the beginning. However, the number of infections prevented per vaccine administered rises over time. Nevertheless, increased risk behaviour reduces the benefit of vaccination. Targeting high-risk men is more successful in reducing and containing the epidemic than targeting low-risk men. In conclusion, the vaccination campaign is effective and should be intensified. High-risk men should be targeted for vaccination and for risk reduction.

To inform current and future vaccination strategies, we describe the seroepidemiology of hepatitis B virus (HBV) infection in ten representative European countries using standardized serology that allowed international comparisons. Between 1996 and 2003, national serum banks were compiled by collecting residual sera or by community sampling; sera were then tested by each country using its preferred enzyme immunoassays and testing algorithm, and assay results were standardized. Information on current and past HBV vaccination programmes in each country was also collected. Of the ten countries, six reported low levels (<3%) of antibodies against HBV core antigen (anti-HBc). Of the eight countries testing for HBV surface antigen (HBsAg), the highest prevalence was reported in Romania (5·6%) and in the remaining seven countries prevalence was <1%. Universal HBV vaccination programmes had been established in seven countries as recommended by the World Health Organization, but the seroprevalence of antibodies against HBsAg (anti-HBs) was lower than the reported vaccine coverage in three countries. Regular serological surveys to ascertain HBV status within a population, such as reported here, provide important data to assess the need for and to evaluate universal HBV vaccination programmes.

Streptococcus agalactiae is a genetically diverse organism; when typed by pulsed-field gel electrophoresis (PFGE), multiple types appear within a single serotype. We tested whether S. agalactiae PFGE types correspond to a specific serotype within individuals, and different individuals from the same geographic area. A total of 872 S. agalactiae isolates from 152 healthy individuals were classified by PFGE and capsular serotype. Serotype V was the most homogeneous (Simpson's diversity index 0·54); and types III, II and Ib were mostly heterogeneous (Simpson's diversity index ⩾0·90). Within an individual, isolates with the same PFGE patterns had identical capsular types, but across individuals the same PFGE types sometimes occurred in different serotypes. Capsular type alone is insufficient to define epidemiological relatedness. Although PFGE types appear to be a valid surrogate for capsular typing of isolates from the same individual, it is not a valid surrogate for serotype in isolates from different individuals.

We investigated an outbreak of Salmonella Enteritidis (SE) infections linked to raw mung bean sprouts in 2000 with two case-control studies and reviewed six similar outbreaks that occurred in 2000–2002. All outbreaks were due to unusual phage types (PT) of SE and occurred in the United States (PT 33, 1, and 913), Canada (PT 11b and 913), and The Netherlands (PT 4b). PT 33 was in the spent irrigation water and a drain from one sprout grower. None of the growers disinfected seeds at recommended concentrations. Only two growers tested spent irrigation water; neither discarded the implicated seed lots after receiving a report of Salmonella contamination. We found no difference in the growth of SE and Salmonella Newport on mung beans. Mung bean sprout growers should disinfect seeds, test spent irrigation water, and discontinue the use of implicated seed lots when pathogens are found. Laboratories should report confirmed positive Salmonella results from sprout growers to public health authorities.

In the last decade, a declining prevalence of HCV infection has been described in injecting drug users (IDUs) in different countries. This study is the first to assess temporal trends in drug-injecting patterns, HCV infection rates and viral genotype distribution in 770 Brazilian IDUs, recruited by two cross-sectional studies (1994–1997 and 1999–2001). A substantial decline in the prevalence of HCV infection was found over the years (75% in 1994 vs. 20·6% in 2001, P<0·001) that may be a consequence of the significant reduction in the overall frequencies of drug injection and needle-sharing, as well as the participation of IDUs in initiatives aimed at reducing drug-related harm. No trend was found in terms of viral genotype distribution. Despite the favourable scenario, preventive measures must be maintained, especially in vulnerable subgroups such as young or new injectors, where risky behaviours through direct and indirect sharing practices remain common.

A multi-state outbreak of Salmonella enterica serovar Saintpaul infection occurred in Australia during October 2006. A case-control study conducted in three affected jurisdictions, New South Wales, Victoria and Australian Capital Territory, included 36 cases with the outbreak-specific strain of S. Saintpaul identified by multiple locus variable-number tandem repeat analysis (MLVA) in a faecal specimen and 106 controls. Consumption of cantaloupe (rockmelon) was strongly associated with illness (adjusted OR 23·9 95%, 95% CI 5·1–112·4). S. Saintpaul, with the outbreak MLVA profile, was detected on the skin of two cantaloupes obtained from an implicated retailer. Trace-back investigations did not identify the specific source of the outbreak strain of S. Saintpaul, but multiple Salmonella spp. were detected in environmental samples from farms and packing plants investigated during the trace-back operation. Cantaloupe production and processing practices pose a potential public health threat requiring regulatory and community educational interventions.

Genotype 5 (G5) was initially discovered and is still mainly diagnosed in South Africa. No cases of G5 have ever been reported from the Middle East countries. The aim of the study was to determine the hepatitis C virus (HCV) genotype distribution in Syria and the prevalence of G5 in this country. Genotyping of HCV was performed in 636 consecutive HCV patients referred to eight medical centres in Syria over a 3-year period. Genotype 4 was the most frequent genotype (375 patients, 59%) followed by genotype 1 (181 patients, 28·5%) and G5 (64 patients, 10%). The majority of G5 patients (56 cases, 87%) live in the north of Syria, including 21 cases (33%) from Azaz, a small city close to Turkey. No obvious epidemiological reason for such high prevalence of G5 was found.

The aim of this study was to assess the effects of reductions in the number of isolates tested by phage-typing on the recognition of outbreaks of salmonellosis. Five outbreaks (categorized as ‘small’, ‘medium’ or ‘large’) which occurred in England in 2005 were used as examples. The outbreaks were caused by serotypes which were subdivided by phage-typing. Results indicated that reducing the number of isolates phage-typed would have an impact on the surveillance system, with one outbreak likely to have been missed altogether. However, this does not have a great effect on the ‘time-to-detection’ for the other outbreaks. Assuming no testing for phage-typing was undertaken it is likely that two out of five outbreaks would not have been detected. Assessing the value of phage-type information is important not only in deciding on the efficiency of the current surveillance system but also in providing a basis upon which to assess more detailed typing methodologies such as an antibiogram of molecular profile.