To date there has been no satisfactory explanation of the worldwide excess of tuberculosis (TB) notifications among adult males. We investigated the epidemiological basis for sex differences in TB notifications in high-burden countries using available group-level data. Multiple linear regression analysis was used to explore the ecological relationship between smoking and sex differences in TB notifications among high-burden countries. Cigarette consumption was a significant predictor of the sex ratio of TB notifications, and explained 33% of the variance in the sex ratio of TB notifications. Our findings suggest that smoking is an important modifiable factor which has a significant impact on the global epidemiology of TB, and emphasize the importance of tobacco control in countries with a high incidence of TB. This analysis provides support for the interpretation of sex differences in worldwide TB notification rates as indicative of true differences in the epidemiology of TB between males and females.

Severe acute respiratory syndrome (SARS) is a newly emerged infectious disease with a high case-fatality rate and devastating socio-economic impact. In this report we summarized the results from an epidemiological investigation of a SARS outbreak in a hospital in Tianjin, between April and May 2003. We collected epidemiological and clinical data on 111 suspect and probable cases of SARS associated with the outbreak. Transmission chain and outbreak clusters were investigated. The outbreak was single sourced and had eight clusters. All SARS cases in the hospital were traced to a single patient who directly infected 33 people. The patients ranged from 16 to 82 years of age (mean age 38·5 years); 38·7% were men. The overall case fatality in the SARS outbreak was 11·7% (13/111). The outbreak lasted around 4 weeks after the index case was identified. SARS is a highly contagious condition associated with substantial case fatality; an outbreak can result from one patient in a relatively short period. However, stringent public health measures seemed to be effective in breaking the disease transmission chain.

A family cluster of three cases of Escherichia coli O157 infection was identified in France. Two cases developed haemolytic–uraemic syndrome. The source was fresh unpasteurized goats' cheese, produced by an independent producer. Three E. coli O157 strains, isolated from one HUS case and faeces of one cow and one goat, were indistinguishable by toxin type and PFGE pattern.

Nyanza Province, Kenya is characterized by poor water quality and high diarrhoea prevalence. To address these problems, nurses in a maternal and child health clinic in Homa Bay, Kenya were trained in household water chlorination with a locally available, social marketed product, and in six steps of proper hand washing. They were asked to communicate this information to their clients. Interviews immediately following the training by nurses were conducted on 220 clients, of whom 168 (76%) reported being taught both procedures during their clinic visit. After 2 weeks, free chlorine residuals were present in stored drinking water in 67 out of 98 (68%) clients' homes and, 1 year later, in 36 out of 51 (71%) clients' homes. After 2 weeks, all six hand-washing steps were correctly demonstrated by 41 (44%) out of 93 clients, and by 17 out of 51 (34%) 1 year later. This brief, practical intervention shows promise for vulnerable populations.

In The Netherlands, a national programme for the surveillance of zoonotic bacteria in farm animals has been operative since 1997. We describe the results of the surveillance of Salmonella spp. in flocks of laying hens and broilers and of Campylobacter spp. in broiler flocks in the period 1999–2002. The prevalence of Salmonella spp. in laying-hen flocks has significantly decreased from 21·1% in 1999 to 13·4% in 2002. This decreasing trend might indicate that the control measures taken by the poultry industry were effective. S. Enteritidis was the predominant serovar in laying hens accounting for one third of the positive flocks. Although prevalence estimates for Salmonella spp. in broiler flocks did not yield a significant decreasing trend in 1999–2002, a decrease in Salmonella prevalence to 11% was measured in 2002. During the study period, S. Paratyphi B var. Java emerged in broilers to become the predominant serovar in 2002 accounting for one third of the positive flocks. The prevalence of Campylobacter spp. in broiler flocks did not increase nor decrease continuously between 1999 and 2002, which roughly corresponds with the monitoring results from the poultry industry. In this period, the estimated flock prevalence roughly averaged around 20%, with C. jejuni being the predominant species. The approach of monitoring presented in this paper can serve as a blueprint for monitoring schemes in farm animal populations to be developed in the context of the EC Zoonoses Directive.

A large serosurvey was carried out in Luxembourg in 2000–2001, to determine the population immunity against a number of vaccine-preventable infections including diphtheria and pertussis. Immunity to diphtheria and pertussis was assessed using an in-house neutralization assay and a commercial ELISA test respectively. Mean pertussis antibody activity decreased from 4 to 8 years of age, reflecting the effects of waning of vaccine-induced immunity. Mean pertussis antibody activity increased during adolescence due to infection in previously vaccinated individuals and levelled out after approximately 20 years of age. For adults >25 years age, a statistically significant 30% difference in mean antibody activity between men and women was observed. The proportion of seronegatives for diphtheria among children and adolescents aged <20 years was 2·5% reflecting the high vaccination coverage. The proportion seronegative for diphtheria tended to increase with age such that 42% of individuals aged >40 years were seronegative. Our study supports the recently introduced acellular pertussis vaccine booster at 6 years to reduce pertussis transmission in school-aged children and adolescents.

Both influenza and respiratory syncytial virus (RSV) cause epidemics of respiratory illness of variable severity during the winter season. Influenza in particular has been blamed for hospital winter bed pressures, although it is thought that RSV may also play a role. Human metapneumovirus (hMPV) is a new respiratory virus reported to be important in children; only a limited number of studies are available for adult populations. We aimed to determine initially the burden of virologically confirmed infections, i.e. influenza, RSV and hMPV using polymerase chain reaction (PCR) technology and, in addition, to assess the feasibility of this approach as a surveillance tool for these respiratory viruses. Adult patients admitted to hospital in the previous 24 hours with onset of acute respiratory symptoms in the last 14 days were asked to participate. Informed written consent was obtained and nose and throat swabs taken. Multiplex PCR for influenza A (H1N1 and H3N2), influenza B and RSV A and B were carried out together with a separate PCR for hMPV. A total of 219 patients in 2001–2002 and 216 in 2002–2003 were tested and the combined results for both seasons were: 8 positive for influenza A/H1N1, 14 for influenza A/H3N2, 2 for influenza B, 14 for RSV A and 6 for RSV B. Most patients (261/435) were >65 years and most positives (30/44) were found within this age group. A number of patients aged >65 years who were positive for influenza (12/15) reported having had vaccine. In total, 373 samples were tested for hMPV and 20 were found positive across all age groups except the 45–54 years age group. As influenza activity was low during the study period the impact of infection on admissions could not be assessed. Nevertheless the viruses studied accounted for 15% of hospital admissions for respiratory infection. Most patients were aged >65 years, as expected. In the two years studied RSV and hMPV were each responsible for as many hospitalized cases of respiratory infection as influenza. Influenza infection must be considered even in those who give a history of vaccination. The molecular methods used in this study showed that surveillance of these respiratory viruses can be conducted and may help in the management of patients.

Mucormycosis is a fairly rare fungal infection caused by ubiquitous fungi of the order Mucorales and primarily affects immunocompromised hosts. A series of 16 cases of invasive mucormycosis admitted to three referral centres in Beirut, Lebanon between 1981 and 1999 is described. It includes 12 patients with rhinocerebral, three with cutaneous, and one with pulmonary infection. Onset of symptoms occurred in the summer and autumn in 15 out of 16 patients, showing a statistically significant seasonal variation (P=0·007) A recent report of 19 patients from Tel Aviv describes a strikingly similar seasonal pattern. Studies on atmospheric concentration of Mucorales spores in the Eastern Mediterranean are lacking. Weather pattern analysis in Beirut revealed clustering of onset of invasive mucormycosis at the end of a dry, warm period, which begins around May and ends in October. Mucormycosis incidence appears to be seasonal in the Eastern Mediterranean.

In the summer of 2001 an outbreak of Escherichia coli O157 gastroenteritis affected staff and residents of a care home for the elderly in the West Midlands, UK. E. coli O157 phage type 2 was isolated from faeces in eight patients and 12 staff members. Thirty-five staff and 40 residents met the case definition for clinical gastrointestinal infection. Serological testing identified a further 14 possible cases of infection amongst asymptomatic staff and residents. The outbreak was atypical, as the disease seemed to be milder than has been observed in past outbreaks in similar settings. The index case, a member of staff, developed bloody diarrhoea and haemolytic–uraemic syndrome (HUS), but only one resident developed bloody diarrhoea and required hospitalization. No deaths occurred, despite the high-risk nature of the affected population. The source of the outbreak could not be identified. The prolonged nature of the outbreak and observed lapses in infection control practices indicated that person-to-person spread was the likely route of transmission. This outbreak illustrates the importance of observing appropriate infection control measures in the institutions providing residential and nursing care to the elderly.

Cryptosporidium has become increasingly recognized as a pathogen responsible for outbreaks of diarrhoeal illness in both immunocompetent and immunocompromised persons. In August 2001, an Illinois hospital reported a cryptosporidiosis cluster potentially linked to a local waterpark. There were 358 case-patients identified. We conducted community-based and waterpark-based case-control studies to examine potential sources of the outbreak. We collected stool specimens from ill persons and pool water samples for microscopy and molecular analysis. Laboratory-confirmed case-patients (n=77) were more likely to have attended the waterpark [odds ratio (OR) 16·0, 95% confidence interval (CI) 3·8–66·8], had pool water in the mouth (OR 6·0, 95% CI 1·3–26·8), and swallowed pool water (OR 4·5, 95% CI 1·5–13·3) than age-matched controls. Cryptosporidium was found in stool specimens and pool water samples. The chlorine resistance of oocysts, frequent swimming exposures, high bather densities, heavy usage by diaper-aged children, and increased recognition and reporting of outbreaks are likely to have contributed to the increasing trend in number of swimming pool-associated outbreaks of cryptosporidiosis. Recommendations for disease prevention include alteration of pool design to separate toddler pool filtration systems from other pools. Implementation of education programmes could reduce the risk of faecal contamination and disease transmission.

False-positive serological reactions (FPSR) due to infections with Yersinia enterocolitica serotype O[ratio ]9 (YeO[ratio ]9) are a problem in tests for brucellosis. In the present study, FPSR in classical and novel tests for brucellosis following experimental infections of pigs with YeO[ratio ]9 were compared with responses of B. suis biovar 2-inoculated pigs. FPSR were limited to 2–9 weeks post-YeO[ratio ]9 inoculation, while B. suis-infected pigs were test-positive throughout the 21-week period of investigation. Although YeO[ratio ]9-inoculated pigs exhibited FPSR in Brucella tests for a limited period of time, the serological responses in a YeO[ratio ]9-purified O-antigen indirect ELISA did not decrease accordingly. Analysis of available cross-sectional serum samples from pig herds naturally infected with YeO[ratio ]9 or B. suis biovar 2 confirmed that the observed difference in the duration of the serological responses between the two infections could be used to discriminate between herds infected with B. suis biovar 2 and YeO[ratio ]9.

The aims were to (1) investigate the aetiology of probable meningococcal disease, where a clinical diagnosis is made in the absence of laboratory data, and (2) evaluate the impact of the Men C vaccination programme in England and Wales. Multiple linear regression analyses were carried out using data reported to Enhanced Surveillance of Meningococcal Disease (ESMD) and laboratory reports of isolates of organisms causing symptoms that mimic meningococcal disease. Confirmed meningococcal disease appeared to be a significant predictor of probable disease. Thus, an additional reduction in meningococcal disease attributable to the serogroup C vaccination campaign was evident in probable disease over and above that observed in confirmed cases alone. Enteroviruses were a significant contributor to cases of probable meningitis and influenza appeared to be a significant contributor to probable cases of septicaemia. This analysis confirms the success seen following the Men C vaccination campaign and gives an indication of the aetiologies of other causes of probable meningitis and septicaemia reported to ESMD.

The distribution of antibody levels to Legionella (L.) pneumophila (serotypes 1–7) was compared between subjects who worked near the source of a large outbreak of Legionnaires' disease (n=668) and a population sample of comparable age (n=480). In a previous analysis of these data, it was estimated that 80% of those working near the source were infected with L. pneumophila. However, the estimation procedure implicitly assumes that the probability of infection does not depend on the antibody level of a person before exposure. This is questionable, as antibodies could protect against infection. We have now estimated the minimum value consistent with the data on the number of infected persons. We observed that a minimum of 40% [95% confidence interval (CI) 32–48] of those working near the source and 13% (95% CI 8–18) of those working further away were infected with L. pneumophila. Implications of these findings for design options in future research are discussed.

We report an outbreak of hepatitis A that occurred in the city of Bari (Apulian region) in June 2002. Overall, 26 cases were observed over a 4-week period. These were traced back to the index case, a food handler who prepared various food products for sale over the counter at a store in the district (OR 5·36, CI 95% 1·58–19·25). Laboratory investigations confirmed that the outbreak was due to a point source and identified a new genotype IB variant. There is a possible indication for administration of hepatitis A vaccine to food handlers, although further evidence of an acceptable cost–benefit ratio needs to be ascertained.

To investigate risk factors during a community outbreak of hepatitis A we carried out a case- control study of 35 cases and 49 matched controls using an interviewer-administered questionnaire on clinical history, travel, household details including domestic toilet facilities, infectious contacts, and food history. Of 99 cases notified in the city during the outbreak year, 50 (51%) were young adults age 15–34 years. Hepatitis A infection was independently associated with household contact with a case (P=0·0005), and sharing a household with children in primary school (OR 3·4, 95% CI 1·2–9·5, P=0·008) with risk increasing with number of primary-school pupils in the household (χ2 for linear trend 6·47, P=0·01). We concluded that in a population with a low prevalence of hepatitis A, adults who live in the same household as primary-school-age children are at increased risk of acquiring the infection during community outbreaks.

The antimicrobial resistance profiles of Campylobacter isolates recovered from a range of retail food samples (n=374) and humans (n=314) to eight antimicrobial compounds were investigated. High levels of resistance in food C. jejuni isolates were observed for ceftiofur (58%), ampicillin (25%) and nalidixic acid (17%) with lower levels observed for streptomycin (7·9%) and chloramphenicol (8·3%). A total of 80% of human C. jejuni isolates were resistant to ceftiofur, while 17% showed resistance to ampicillin and nalidixic acid, 8·6% to streptomycin and 4·1% to chloramphenicol. Resistance to clinically relevant antimicrobials such as erythromycin, ciprofloxacin and tetracycline was 6·7, 12, and 15% respectively for all food isolates and was similar to corresponding resistance prevalences observed for human isolates, where 6·4, 12 and 13% respectively were found to be resistant. Comparisons of C. jejuni isolates in each location showed a high degree of similarity although some regional variations did exist. Comparison of total C. jejuni and C. coli populations showed minor differences, with C. jejuni isolates more resistant to ampicillin and ceftiofur. Multidrug resistance patterns showed some profiles common to human and clinical isolates.

In Greece the public health surveillance for most infectious diseases, including shigellosis, is not well developed. However, four waterborne outbreaks of shigellosis have been recorded in Greece in the last three decades, in different areas of the country, under different environmental and socioeconomic conditions. This study presents the epidemiological characteristics of these four outbreaks in order to examine common points and differences and to investigate their possible association with environmental and socioeconomic conditions. All four outbreaks were caused by Shigella sonnei and related to drinking water. Epidemic curves, distribution of cases by age and gender, hospitalization rates, environmental conditions and laboratory results were compared. The outbreaks seemed to correspond to two different ‘models’ presenting two characteristic types of epidemic waves related to specific environmental conditions. The attack rates for the general population varied from about 9 to 13% and were similar for both sexes. Children were affected mostly. In these outbreaks there was a strong suspicion of contamination of the water distribution system from the sewage network, highlighting the importance of environmental health control measures.

In recent years, the control or eradication of scrapie and any other transmissible spongiform encephalopathies (TSEs) possibly circulating in the sheep population has become a priority in Britain and elsewhere in Europe. A better understanding of the epidemiology of scrapie would greatly aid the development and evaluation of control and eradication strategies. Here we bound the range of key epidemiological parameters using a combination of relatively detailed pathogenesis and demography data, more limited data on susceptibility and incubation times, and recent survey data on scrapie incidence in Great Britain. These data are simultaneously analysed using mathematical models describing scrapie transmission between sheep and between flocks. Our analysis suggests that occurrence of scrapie in a flock typically provokes changes in flock management that promote termination of the outbreak, such as the adoption of selective breeding, and that a large fraction of cases (possibly over 80%) goes undetected. We show that the data analysed are consistent with the within-flock reproduction number of scrapie lying in the range 1·5–6, consistent with previous epidemiological studies.

This paper describes the features of an outbreak of early syphilis in an institution for the care of adults with mental disorders. A case-note review was performed. In the period June to November 2001, 87 cases of syphilis were diagnosed [25 primary, 21 secondary and 41 early latent syphilis in 983 inmates (crude attack rate 8·9%)]. Among them 82 were heterosexual, four were homosexual or bisexual, and for one case sexual preference was not established. About half the cases were known to be promiscuous. The initial case was not identified. Penicillin therapy was administered to all cases and all known or suspected sexual contacts. Sporadic cases of syphilis have, however, continued to emerge from time to time. Institutions for patients with mental disorders are vulnerable to sexually transmitted diseases, and special strategies should be devised for their control.

Meningitis epidemics have a strong environmental component in Africa with the most severe epidemics occurring in the Sahelian region known as the Meningitis Belt. The objective of this study is to evaluate an ecological model based on absolute humidity and land cover type to predict the location of these epidemics. The risk model is evaluated prospectively based on epidemics occurring in Africa from January 2000 to April 2004. Seventy-one epidemics occurred during this time period affecting 22% of continental African districts. The model predicted their location with a sensitivity of 88%. The evaluation also suggests that epidemics may be extending south of the Sahel, which is consistent with environmental changes in the region. This model could be used to select priority areas for the introduction of the newly developed conjugate meningococcal vaccines. Further studies are needed to enhance our understanding of the complex relationship between meningitis epidemics and the environment.