In January 1940 British Ministry of Health circular 1307 proposed the introduction of mass childhood diphtheria immunization. This was a policy reversal after a decade during which opportunities for diphtheria prophylaxis were ignored, or resisted on grounds of cost. Diphtheria toxoid was to be the first of many centrally funded childhood immunizations in the UK and it set a pattern that has now held good for over 70 years. The circumstances in 1940 were particularly fortuitous, and diphtheria toxoid has since given successive generations of children a lifetime's protection from the disease; but difficulties have been experienced in introducing and evaluating some of the more recent immunizations, and in maintaining and justifying them in the face of parental scepticism and academic or pressure-group opposition, however ill-founded this may have been. The task of decision-making with regard to new candidate vaccines demands a careful balancing against the costs of the expected benefits during the recipient's lifespan.

Emergence of the highly pathogenic avian influenza (HPAI) H5N1 virus in Egypt in mid-February 2006 caused significant losses for the poultry industry and constituted a potential threat to public health. Since late 2007, there has been increasing evidence that stable lineages of H5N1 viruses are being established in chickens and humans in Egypt. The virus has been detected in wild, feral and zoo birds and recently was found in donkeys and pigs. Most of the outbreaks in poultry and humans occurred in the highly populated Nile delta. The temporal pattern of the virus has changed since 2009 with outbreaks now occurring in the warmer months of the year. Challenges to control of endemic disease in Egypt are discussed. For the foreseeable future, unless a global collaboration exists, HPAI H5N1 virus in Egypt will continue to compromise the poultry industry, endanger public health and pose a serious pandemic threat.

Rabies is considered one of the oldest infectious diseases known to humans. However, the first written reports on rabies cases in the Americas did not appear until the first decade of the 18th century from Mexico. In an attempt to clarify if the disease was already present in pre-Columbian times, we searched for evidence in the Maya and Aztec cultures. Other sources of information were early manuscripts written by the conquistadors and early explorers. We did not identify any unequivocal direct evidence that the disease rabies was known in pre-Columbian Central America but sufficient circumstantial evidence is available suggesting that (bat) rabies was already present in these early times.

The 2007–2009 human Q fever epidemic in The Netherlands attracted attention due to its magnitude and duration. The current epidemic and the historical background of Q fever in The Netherlands are reviewed according to national and international publications. Seroprevalence studies suggest that Q fever was endemic in The Netherlands several decades before the disease was diagnosed in dairy goats and dairy sheep. This was in 2005 and the increase in humans started in 2007. Q fever abortions were registered on 30 dairy goat and dairy sheep farms between 2005 and 2009. A total of 3523 human cases were notified between 2007 and 2009. Proximity to aborting small ruminants and high numbers of susceptible humans are probably the main causes of the human Q fever outbreak in The Netherlands. In general good monitoring and surveillance systems are necessary to assess the real magnitude of Q fever.

West Nile virus (WNV) is now endemic in the USA. After the widespread surge of virus activity across the USA, research has flourished, and our knowledge base has significantly expanded over the past 10 years since WNV was first recognized in New York City. This article provides a review of the virology of WNV, history, epidemiology, clinical features, pathology of infection, the innate and adaptive immune response, host risk factors for developing severe disease, clinical sequelae following severe disease, chronic infection, and the future of prevention.

Leptospirosis is the most widespread zoonosis in the world. Humans become infected through contact with the urine of carrier animals, directly or via contaminated environments. This review reports available data on animal leptospirosis in ten tropical islands: Barbados, Martinique, Guadeloupe, Grenada, Trinidad, New Caledonia, Hawaii, French Polynesia, La Réunion and Mayotte. Leptospirosis is endemic in these insular wild and domestic fauna. Each island presents a specific panel of circulating serovars, closely linked with animal and environmental biodiversity, making it epidemiologically different from the mainland. Rats, mongooses and mice are proven major renal carriers of leptospires in these areas but dogs also constitute a significant potential reservoir. In some islands seroprevalence of leptospirosis in animals evolves with time, inducing changes in the epidemiology of the human disease. Consequently more investigations on animal leptospirosis in these ecosystems and use of molecular tools are essential for prevention and control of the human disease.

The self-controlled case-series method was originally developed to investigate potential associations between vaccines and adverse events, and is now commonly used for this purpose. This study reviews applications of the method to vaccine safety investigations in the period 1995–2010. In total, 40 studies were reviewed. The application of the self-controlled case-series method in these studies is critically examined, with particular reference to the definition of observation and risk periods, control of confounders, assumptions and potential biases, methodological and presentation issues, power and sample size, and software. Comparisons with other study designs undertaken in the papers reviewed are also highlighted. Some recommendations are presented, with the emphasis on promoting good practice.

Over the last 40 years, the dynamics of hepatitis C virus (HCV) infection in drug users has been affected by the illicit drug market, the health environment including the devastating impact of the HIV/AIDS epidemic which erupted in the 1980s, and the diffusion of substitution treatment beginning in 1995. The purpose of this literature review is to present the dynamics of HCV infection in drug users in France over the last 40 years. Two prevalence studies of HCV infection in the general population were conducted by the French Institute for Public Health Surveillance in 1994 and 2004 and were the touchstone data sources for this analysis. Hypotheses constructed from the findings of these two studies were examined in light of results reported by multicentre prevalence and incidence studies in drug-user populations. The incidence of HCV infection in drug users in France reached a peak in the late 1980s or early 1990s after a lengthy period of epidemic expansion. Implementation of a risk reduction policy enabled a very significant reduction in the incidence of HCV infection in drug users over the last 20 years, leading to incidence figures which are now 10–15% of the 1990 estimate.

The objectives of our study were to identify and categorize primary research investigating swine/pork as a source of zoonotic hepatitis E virus (HEV) using the relatively new technique of scoping study, and to investigate the potential association between human exposure to swine/pork and HEV infection quantitatively using systematic review/meta-analysis methodology. From 1890 initially identified abstracts, 327 were considered for the review. Five study design types (cross-sectional, prevalence, genotyping, case-report and experimental transmission studies) were identified. A significant association between occupational exposure to swine and human HEV IgG seropositivity was reported in 10/13 cross-sectional studies. The association reported between pork consumption and HEV IgG seropositivity was inconsistent. The quantification of viral load in swine and retail pork, viral load required for infection in primates, cohort and case-control studies in humans, and formal risk assessment are recommended before specific public-health policy actions are taken.

A literature search traced existing information on meningococcal disease in Asia. Reviewed data describing the epidemiology of meningococcal disease in Asia are incomplete, due in part to absence of surveillance in many countries, poor bacterial detection methods and social and healthcare barriers to disease reporting. This suggests that meningococcal disease in some Asian countries may be under-recognized, with a need to introduce/improve existing surveillance and case identification systems. Nevertheless, in some developing Asian countries, the disease burden may be significant. Serogroup A meningococcal epidemics are responsible for high morbidity and mortality in some countries and continue to be an ongoing threat, particularly in developing countries. There is an increasing role played by serogroups C, Y, and W-135 in invasive disease, indicating evolving meningococcal disease epidemiology in some countries. Multivalent meningococcal conjugate vaccines offer new opportunities in the region for reducing the meningococcal disease burden.

We performed a systematic literature review to assess the effectiveness of chemoprophylaxis for contacts of sporadic cases of invasive meningococcal disease (IMD) in educational settings. No studies directly compared IMD risk in contacts with/without chemoprophylaxis. However, compared to the background incidence, an elevated IMD risk was identified in settings without a general recommendation for chemoprophylaxis in pre-schools [pooled risk difference (RD) 58·2/105, 95% confidence interval (CI) 27·3–89·0] and primary schools (pooled RD 4·9/105, 95% CI 2·9–6·9) in the ~30 days after contact with a sporadic IMD case, but not in other educational settings. Thus, limited but consistent evidence suggests the risk of IMD in pre-school contacts of sporadic IMD cases is significantly increased above the background risk, but lower than in household contacts (pooled RD for household contacts with no chemoprophylaxis vs. background incidence: 480·1/105, 95% CI 321·5–639·9). We recommend chemoprophylaxis for pre-school contacts depending on an assessment of duration and closeness of contact.

Healthcare-associated hepatitis B virus (HBV) outbreaks have been reported in the USA and from several countries in Europe. Patient-to-patient transmission of HBV in these settings has been linked to several different types of exposure but one of the most common exposures implicated is the use of ‘finger-stick’ lancet devices for blood glucose testing. This article is an account of the investigations into a series of HBV outbreaks linked to the use of lancing devices in community healthcare settings in the UK. Between February 2004 and December 2006, nine individuals with acute HBV infection were reported to five local units of the Health Protection Agency. Investigations identified a further 12 individuals with HBV infection in residents in these settings. The epidemiological and environmental evidence suggests that HBV transmission occurred mostly from a significant breakdown in infection control measures in blood glucose testing. The occurrence of these outbreaks has highlighted the confusion that exists and the need for clear recommendations regarding the use of such devices in the UK.

Most viruses are maintained by complex processes of evolution that enable them to survive but also complicate efforts to achieve their control. In this paper, we study patterns of evolution in foot-and-mouth disease (FMD) serotype C virus isolates from Kenya, one of the few places in the world where serotype C has been endemic and is suspected to remain. The nucleotide sequences encoding the capsid protein VP1 from eight isolates collected between 1967 and 2004 were analysed for patterns of sequence divergence and evolution. Very low nucleotide diversity (π=0·0025) and remarkably little change (only five segregating sites and three amino-acid changes) were observed in these isolates collected over a period of almost 40 years. We interpret these results as being suggestive of re-introductions of the vaccine strain into the field. The implications of these results for the maintenance of serotype C FMD virus and the use of vaccination as a control measure in Kenya are discussed.

Between March and June 2008, 12 cases of hepatitis A were notified in Winchester. Cases were from a primary school and a nursery school with no direct linkage. Hepatitis A virus (HAV) RNA sequenced from nine cases confirmed the strain in both schools to be identical. The outbreak could have affected three other schools and a maternity unit and was controlled by immunization and screening of neonates in the maternity unit by dried blood spots. No neonates were infected and no further cases were reported until 5 months later when the index case's mother became infected with same strain of virus associated with the outbreak despite vaccination. Neither the source of the outbreak or the subsequent infection of the index case's mother was identified; however, with the timing of the cases continued transmission in the community by children with asymptomatic infection or a recurrent source cannot be ruled out.

In May 2008 the Nijmegen Municipal Health Service (MHS) was informed about an outbreak of atypical pneumonia in three in-patients of a long-term psychiatric institution. The patients had been hospitalized and had laboratory confirmation of acute Q fever infection. The MHS started active case finding among in-patients, employees of and visitors to the institution. In a small meadow on the institution premises a flock of sheep was present. One of the lambs in the flock had been abandoned by its mother and cuddled by the in-patients. Samples were taken of the flock. Forty-five clinical cases were identified in employees, in-patients and visitors; 28 were laboratory confirmed as Q fever. Laboratory screening of pregnant women and persons with valvular heart disease resulted in one confirmed Q fever case in a pregnant woman. Of 27 samples from animals, seven were positive and 15 suspect for Coxiella burnetii infection. This outbreak of Q fever in a unique psychiatric setting pointed to a small flock of sheep with newborn lambs as the most likely source of exposure. Care institutions that have vulnerable residents and keep flocks of sheep should be careful to take adequate hygienic measures during delivery of lambs and handling of birth products.

The 2009 meningitis season in Niger was characterized by an early onset, beginning in the very first weeks of the year and peaking from the 12th to the 15th week with 5655 clinical cases over the 4 weeks. From 1 January 2009 to 28 June 2009 (week 26), a total of 13 733 clinical cases of meningitis were reported to the national epidemiological surveillance system with a case-fatality rate of 4·2%. During the season 25 of the 42 health districts reached the epidemic threshold and 11 the alert threshold. Reactive mass vaccination campaigns involving a total of 5 166 741 doses of the polysaccharide meningococcal bivalent (A+C) vaccine progressively controlled the outbreak in most parts of the country. A total of 3755 cerebrospinal fluid samples representing 28·1% of the suspected meningitis cases were analysed. Serogroup A meningococci were the causative agent in 97·5% of the meningococcal cases. Multi-locus sequence typing of 26 meningococal serogroup A strains showed 25 sequence type (ST)7 and one ST2859, both sequence types belonging to the ST5 clonal complex (CC5) of subgroup III. This is the largest epidemic observed in Niger since those of 1995–1996 (59 948 notified cases) and 2000 (14 633 notified cases).

Hepatitis E virus (HEV) infection is as an emerging disease of global importance because it is one of the major causes of acute hepatitis worldwide. There are few reports on the incidence of HEV in the USA. For better assessing the burden of primary HEV infection as well as understanding the epidemiology of HEV in the US population this analysis was conducted to estimate the force of infection of HEV in the USA. HEV force of infection in the general US population was calculated using catalytic models as cumulative markers of past infection from HEV seroprevalence data from the NHANES Survey. In the US population the force of infection was seven infections per 1000 susceptible persons per year. This study shows that in the USA HEV can be acquired locally and from developing countries. HEV is circulating more frequently in the non-Hispanic White racial/ethnic group and those who consume fish more frequently.

Susceptibility to vaccine-preventable diseases in Belgium in 2006 was estimated from a serum survey. Immunoglobulins against measles, mumps, rubella (MMR) and diphtheria at all available ages (1–65 years), and against tetanus in >40-year-olds, were measured by ELISA. Age-standardized overall seronegativity for MMR was low (3·9%, 8·0%, 10·4%, respectively). However, the World Health Organization's targets for measles elimination were not met in 5- to 24-year-olds and about 1 in 7 women at childbearing age (15–39 years) were seronegative for rubella. In adults >40 years, tetanus immunity (87·2%, >0·16 IU/ml) largely exceeded diphtheria immunity (20–45%, >0·1 IU/ml). Despite free universal vaccination against MMR for more than 20 years and against diphtheria and tetanus for almost 60 years, our study revealed specific age groups remaining at risk for infection with these pathogens.

Rates of herpes zoster (HZ) hospitalizations, antiviral prescriptions, and New South Wales emergency-department presentations for age groups <20, 20–39, 40–59 and ⩾60 years were investigated. Trends were analysed using Poisson regression to determine if rates increased following funding of varicella immunization in Australia in November 2005. The regression analysis revealed significantly increasing trends of between 2% and 6% per year in both antiviral prescriptions and emergency-department presentations in all except the <20 years age group. When considered together, the differential changes in rates observed by age group provides preliminary evidence to indicate that HZ incidence is increasing in adults aged >20 years. However, it is not possible to attribute the increasing trends in HZ observed directly to the varicella immunization programme, and continued monitoring and analyses of data for a longer duration, both pre- and post-vaccine introduction, is required.

West Nile virus (WNV) was detected in Italy, in late summer 2008 in horses and birds in the Po valley. As a consequence, an intense WNV surveillance was implemented in that area involving Emilia-Romagna, Veneto and Lombardy. This paper presents the results of the September 2008–November 2009 surveillance on equines, mosquitoes, wild birds, dogs and cattle in Veneto. WNV was detected in equines and dogs, and, to a lesser extent in cattle and wild birds. Simultaneous circulation of Usutu virus was detected by testing wild birds found dead. Usutu virus but not WNV was also found in mosquitoes monitored during 2009. Equine practices monitoring allowed the definition of an area of WNV circulation and the 2008–2009 westward and northward spread of the infection. Although a relatively low number of human cases and a low virus circulation in vectors and birds detected in Veneto region could be considered favourable conditions for a limited risk of human exposure, it remains difficult to predict the possible evolution of the epidemiological situation.