A mathematical model is described which determines the impact of a schedule of vaccination on the time course of a certain class of diseases. The data are the demographic variables and parameters and age-dependent non-fatal and fatal case rates. Given the age- and time-dependent rates of vaccination including coverage and corresponding efficacies, various schedules may be distinguished by either the absolute numbers of cases and deaths avoided or the numbers of cases and deaths avoided per dose of vaccine. The model was applied to meningo-coccal serogroup C disease in France. The outcomes of six different vaccination schedules were examined. In absolute terms, a schedule in which all individuals aged between 2 and 20 years were vaccinated performed best, but this schedule and that in which only 1-year olds were vaccinated performed equally and best in terms of cases prevented, but not lives saved, per dose.

This audit examines the ability of English and Welsh laboratories to diagnose Mycobacterium bovis infection. All 164 clinical laboratories submitting samples to the PHLS Mycobacterium Reference Unit and Regional Centres for Mycobacteriology were surveyed. Twenty per cent of responding centres did not use a pyruvate-containing medium or incubate for the minimum recommended period of 8 weeks. This study demonstrates the potential for the underdiagnosis of M. bovis infection in England and Wales. Possible reasons for underdiagnosis are discussed together with strategies to optimize recovery of M. bovis.

Results of the Dutch laboratory surveillance of bacterial gastroenteritis between 1991 and 2001 are presented and compared with recent findings in general practices and in the community. Between 1996 and 2000 the mean annual number of stools screened by sentinel laboratories was about 1000 samples/100000 inhabitants, which is 4% of the estimated annual incidence of gastroenteritis in the Dutch population. Campylobacter (36/100000 inhabitants) and salmonella (24/100000 inhabitants) were the main pathogens isolated. Since 1996, the incidence of laboratory confirmed salmonellosis decreased by 30%, predominantly among young children. The incidence of campylobacter was highest in urban areas and Salmonella Enteritidis emerged as the predominant serotype in urban areas. Between 1991 and 2001, multi-resistant Salmonella Typhimurium DT104 emerged to comprise up to 15% of all salmonella isolates in 2001. Reported rates of Shigella spp. and Yersinia spp. varied little, with average annual incidences of 3·2 and 1·2 cases/100000 inhabitants, respectively. Escherichia coli O157 (90% STEC) was scarcely found (0·26/100000).

We describe the molecular identification of human tuberculosis (TB) from vertebral bone tissue samples from three different populations of ancient Egypt. The specimens were obtained from the predynastic to early dynastic necropolis of Abydos (7 individuals, c. 3500–2650 B.C.), from a Middle Kingdom to Second Intermediate Period tomb of the necropolis of Thebes-West (37, c. 2100–1550 B.C.) and from five further Theban tombs used in the New Kingdom and the Late Period (39, c. 1450–500 B.C.). A total of 18 cases tested positive for the presence of ancient DNA (aDNA) of the M. tuberculosis complex. Out of the 9 cases with typical macromorphological signs of tuberculous spondylitis, 6 were positive for mycobacterial aDNA (66·7%). Of 24 cases with non-specific pathological alterations, 5 provided a positive result (20·8%). In 50 cases of normally appearing vertebral bones 7 tested positive (14·0%). There were only minor differences in the frequencies between the three populations. These data strongly support the notion that tuberculosis was present and prevalent in ancient Egypt since very early periods of this civilization. The unexpectedly high rate of mycobacterial aDNA in normal bone samples is presumably due to a pre- to perimortal systemic spread of the bacteria and indicates a generalized infection by M. tuberculosis.

The aim of this study was to determine the prevalence of gastroenteritis among children aged 4 years in South Australia. A cross-sectional survey of 9543 South Australian children aged 4 years was undertaken. Parents completed a questionnaire on behalf of their child who had attended a pre-school health check in 1998. The questionnaire covered gastrointestinal and respiratory symptoms experienced by the child in the previous 2 weeks and other risk factors for gastroenteritis. The 2-week prevalence of gastroenteritis among 4-year-old children was 14·2%. The major risk factors for gastroenteritis were presence of persons who had gastroenteritis inside the home, contact with persons who had gastroenteritis outside the home, antibiotic use and sore throat. Medical attention was sought for 20% of children who had gastroenteritis. Gastroenteritis is a significant cause of morbidity among young children and presents a considerable burden on the community. A substantial proportion of these occurrences of highly credible gastrointestinal symptoms may be manifestations of respiratory infections.

The sequelae of Infectious Intestinal Disease (IID) in a population-based sample of cases and matched controls were investigated for a period of 3 months following the initial infection. Incident cases of IID presenting to GPs or occurring in the community and controls were studied at 3 weeks and over a 3-month follow-up period. Cases were six times more likely than controls to have gastrointestinal symptoms, particularly diarrhoea, at 3 weeks. Ten per cent of cases consulted their GP in the 3 months after episode and 2·3% were referred to hospital. GP presentation rates were twice as high in cases. Gastrointestinal symptoms persist after IID, leading to an increased likelihood of GP consultation and hospital referral. Diagnosis of irritable bowel syndrome may be more likely following IID. The burden of IID is likely to be considerable given its high incidence and the frequency of such sequelae.

Echoviruses are the commonest cause of aseptic meningitis (AM). Echovirus type 13 (EV-13) was the second enterovirus serotype associated with different local outbreaks of AM in Spain between February and October 2000. It was the first time that an epidemic AM caused by this virus was recognized in Spain. The index case appeared in the Canary Islands (Canarias). The EV-13 virus was isolated from 135 patients, predominantly from cerebrospinal fluid (CSF). All isolates were from children under 13 years. The age specific peak incidence was in infants under 1 year. Most patients had fever, headache and other meningeal signs. This enterovirus serotype, not previously detected in Spain, caused severe illness with a high attack rate.

Until recently, echovirus 13 has been a very rare cause of aseptic meningitis. We investigated an outbreak of echovirus 13 in central Israel during the summer of 2000 using a prospective case control study and a retrospective study. Echovirus 13 was isolated from 79 cerebrospinal fluid (CSF) specimens from different medical centres in central Israel. Patients' ages ranged from 10 days to 41 years (95% <15 years, M/F ratio 62/38). A total of 128 patients with clinical aseptic meningitis were admitted to the Department of Pediatrics during the outbreak (aged 10 days to 18 years, mean 5·4 years), and 58 CSF samples were processed for viral cultures. Thirty of them did not grow any virus, 26 samples yielded echovirus 13, and 2 samples echovirus 7. The clinical features of patients with echovirus 13 in the CSF were similar to those in whom no virus was isolated or those infected with other enteroviral strains except for higher rate of fever on admission, and prolonged time with fever following the diagnosis in the echovirus 13 patients. CSF cell count varied from 4 to 2333 cells\mm3 with polymorphonuclears (PMN) predominant in >90% of our patients. In a case–control study there was no significant difference between patients and matched controls with regard to parameters such as: day care attendance, recreation in summer camp, swimming pools and at the beach, and consumption of tap water. All the patients in our series recovered fully with no neurological abnormalities. The illness caused by echovirus 13 was benign and involved mainly patients younger than 15 year of age. Several features that characterized this outbreak include relatively high WBC in the blood and a prominent CSF PMN response.

From 1 January 1992 to 31 December 2000, 27 milkborne general outbreaks of infectious intestinal disease (IID) were reported to the Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC). These outbreaks represented a fraction (2%) of all outbreaks of foodborne origin (N=1774) reported to CDSC, but were characterized by significant morbidity. Unpasteurized milk (52%) was the most commonly reported vehicle of infection in milkborne outbreaks, with milk sold as pasteurized accounting for the majority of the rest (37%). Salmonellas (37%), Vero cytotoxin-producing Escherichia coli (VTEC) O157 (33%) and campylobacters (26%) were the most commonly detected pathogens, and most outbreaks were linked to farms (67%). This report highlights the importance of VTEC O157 as a milkborne pathogen and the continued role of unpasteurized milk in human disease.

In England and Wales over the last 30 years there have been 25 reported outbreaks of infection, associated with private water supplies (PWS). The majority (16 outbreaks) were reported after the introduction of enhanced surveillance. Although PWS only serve 0·5% of the population, 36% of drinking water outbreaks are associated with PWS. The main pathogen, campylobacter, was implicated in 13 (52%) outbreaks. Most reported outbreaks (88%) occurred in commercial or Category Two supplies, which potentially affect larger populations. The main factors implicated in these outbreaks are temporary or transient populations, treatment (lack or failure), the presence of animals and heavy rains. The public health problem associated with PWS could be prevented by the identification and understanding of risk factors, by the proper protection of water sources and adequate treatment and maintenance. This could be facilitated through the introduction of a risk assessment as part of a scheme for PWS.

In September 2000 an outbreak of influenza-like illness was reported on a cruise ship sailing between Sydney and Noumea with over 1100 passengers and 400 crew on board. Laboratory testing of passengers and crew indicated that both influenza A and B had been circulating on the ship. The cruise coincided with the peak influenza period in Sydney. Morbidity was high with 40 passengers hospitalized, two of whom died. A questionnaire was sent to passengers 3 weeks after the cruise and 836 of 1119 (75%) responded. A total of 310 passengers (37%) reported suffering from an influenza-like illness (defined as cough, fever, myalgia and weakness) and 528 (63%) had seen a doctor for illness related to the cruise. One-third of passengers reported receipt of influenza vaccination in 2000; however neither their rates of influenza-like illness nor hospitalization were significantly different from those in unvaccinated passengers. A case–control study also found no significant protective effect of influenza vaccination. With the increasing popularity of cruise vacations, such outbreaks are likely to affect increasing numbers of people. Whilst influenza vaccination of passengers and crew may afford some protection, uptake and effectiveness may not be sufficient to prevent outbreaks. Surveillance systems and early intervention measures, such as antiviral therapies, should be considered to detect and control such outbreaks.

In the light of rising numbers of tuberculosis (TB) cases in the United Kingdom, the problem of anti-tubercular drug resistance remains a significant concern. Drug resistant TB cases are more difficult and costly to treat, and require appropriate treatment and control mechanisms. This matched case control study aimed to investigate risk factors for resistance in Leicestershire, using data for laboratory isolates of Mycobacterium tuberculosis identified from 1993 to 1998. Each case, defined as culture positive laboratory isolates resistant to at least one first-line drug, was matched to four fully sensitive controls on age, sex and ethnic group. Twenty-three cases and 81 controls were included in the analysis. Drug resistance in Leicestershire was found to be associated with poor adherence to treatment (OR 4·8, 95% CI 1·6–14·4, P=0·005) and with previous TB (OR 3·7, 95% CI 1·2–11·8, P=0·022). These findings emphasize the need to provide support to patients taking treatment in order to maximize adherence.

In this study an analysis was made of economic costs and medical effects (by cost-effectiveness and cost–benefit analysis) associated with measles vaccination in a hypothetical Western European country. We analysed ten vaccination options in terms of past and future vaccination coverage. We show that several of the proposed strategies for improving measles vaccination coverage are preferable to maintaining the existing policies, regardless of past coverage and the viewpoint of the analysis. For society, very high coverage (95%) two-dose vaccination is most optimal, irrespective of past vaccination coverage. The addition of a one-time campaign (to reduce susceptibility in (pre-)adolescent age groups) to such a high coverage two-dose vaccination programme is cost-saving to the health-care payer and to society when coverage in the past was low ([les ]70%). Even when coverage in the past was high (90%) for more than a decade, this ‘maximum strategy’ could be implemented at an acceptable cost to the health-care payer (incremental direct costs per discounted life-year gained <€30000), and at net savings to society.

Bovine tuberculosis is a zoonotic disease that not only causes huge economic losses but also poses an important risk for human infection. The definitive identification of a clinical isolate relies on time-consuming, highly specialized and laborious biochemical tests. We have developed a method for the rapid and reliable identification of Mycobacterium bovis and for its simultaneous differentiation from other members of the M. tuberculosis complex. Furthermore, the technique also allowed us to distinguish M. tuberculosis complex members from other Mycobacterial species. The method comprises both a single PCR and a multiplex-PCR and can be confidently applied to samples of both veterinary and human origin.

A method for the analysis of age-stratified antibody prevalence surveys is applied to a previously reported survey of antibody to rubella virus using oral fluid samples in which the sensitivity of the assay used was shown to be compromised. The age-specific distribution of the quantitative results of antibody tests using oral fluids is modelled as a mixture of strong positive, weak positive and negative components. This yields maximum likelihood estimates of the prevalence at each age and demonstrates that, when used in conjunction with mixture modelling techniques, the results of antibody prevalence studies using oral fluids accurately reflect those obtained using sera.

Sixty-six cases of Q fever were diagnosed in people affiliated with a goat-farming co-operative in rural Newfoundland in the spring of 1999. Follow-up studies which included administration of the Short Form 36 Health Survey (SF-36) were conducted 3 and 27 months after the initial outbreak to prospectively follow the effects of acute Q fever on the quality of life of the participants. Twenty-seven months after the outbreak 51% of those who had Q fever reported persistent symptoms including seven participants whose symptoms had initially resolved 3 months after the outbreak. Individuals with Q fever had significantly lower scores on five of the eight scales in the SF-36 and lower scores in the mental and physical summary scales compared to uninfected controls. Although this supports the hypothesis of a ‘post Q fever fatigue syndrome’ (QFFS), further study is warranted.

A case control study was conducted to identify the association of therapeutic injections with acute hepatitis B virus (HBV) infection in Karachi, Pakistan. We enrolled 67 cases of acute HBV infection (IgM anti-HBc positive) and 247 controls (anti-HBc negative) from four hospitals of Karachi during July 2000–June 2001. Exposure to various risk factors during the period relevant to the incubation period of HBV was recorded both from cases and controls using a structured questionnaire. Multivariate logistic regression analysis of the data showed that cases were more likely to have received one injection (OR=4·0; 95% CI 1·4, 11·1), or more than one injection (OR=6·3; 95% CI 3·2, 12·4) compared to controls. The estimated population attributable risk (PAR) for therapeutic injections was 53%. Also the cases compared to controls were more likely to have household size of seven or more (OR=1·9; 95% CI 0·95, 3·9). This study showed that unsafe therapeutic injections appear to be the major risk factor for acute HBV infection and needs immediate focus from public health stand point.

The aim of the present study was to assess the prevalence as well as the possible risk factors of HIV, hepatitis B and hepatitis C, in 194 male prisoners who had been convicted for rape (n=105) or child molestation (n=89). HBsAg, HBeAg, anti-HBc, anti-HBs, anti-HCV and anti-HIV-1/2 were tested for. The participants also completed a standard sociodemographic questionnaire, indicating possible risk factors, the Barratt Impulsiveness Scale, and the life-time history of aggression. Anti-HIV antibodies were not found in any of the prisoners. HBsAg was found in 25 (13%), anti-HBc in 94 (49%), anti-HBs in 40 (21%) and anti-HCV in 13 (6·5%) subjects. Logistic regression analysis showed that anti-HCV positivity was associated with intravenous drug use (OR 20·7, 95% CI 1·1–4·9, P<0·001), while HBsAg positivity was associated separately with being foreign (OR 4·0, 95% CI 0·2–2·5, P<0·01), as well as with impulsiveness score (OR 1·06, 95% CI 0·01–0·11, P<0·02). The prevalence of HBV and HCV infection in this sex offender sample was highly increased in relation to the general population. Since it has been proved that sex offenders are a high-risk group for reoffending, monitoring their health is a necessary step towards prevention of sexually transmitted diseases being spread.

A study was designed to investigate management factors that might influence the shedding of verocytotoxin-producing Escherichia coli (VTEC) O157 by beef cows in Scotland, where there is a particularly high rate of human infection. Thirty-two herds were visited at least monthly over approximately 1 year for collection of fresh faecal pat samples and information on management factors. The faecal pat samples were tested for VTEC O157 by established culture and immunomagnetic separation methods. Questionnaires were completed at the monthly visits to record management factors. Data were analysed using both univariate and multi-factor (GLMM) analysis. Changes in the number of cows in a group, dogs, wild geese, housing, and the feeding of draff (distillers' grains) were statistically significant as risk factors. The event of calving appeared to reduce the likelihood of shedding. Any effects of weaning or turnout were not statistically significant. It appears that the rate of shedding of VTEC O157 is influenced by several factors but possibly the most important of these are the circumstances of animals being housed, or, when outside, the presence of wild geese.

Faecal samples from 146 diarrhoeic lambs and goat kids, and from 511 healthy sheep and goats were screened for the presence of Vero cytotoxin-producing Escherichia coli (VTEC). In healthy sheep and goats, VTEC were isolated in 24·4 and 16·2% of the animals, respectively. Moreover, VTEC were detected in 3·1 and 5·9% of the diarrhoeic lambs and goat kids, respectively. These data suggest that VTEC seems not to be associated with diarrhoea in lambs and goat kids. Only four VTEC strains were eae-positive. The absence of the eae gene in most of these VTEC strains could indicate that these strains are less virulent for humans that the classical eae-positive enterohaemorrhagic E. coli types. However, almost half (42·9%) and 12·2% of VTEC strains isolated from healthy sheep and goats, respectively, belonged to serotypes associated with severe diseases in humans.