Newcastle disease (ND) is one of the most important and widespread avian pests. In Africa, backyard poultry production systems are an important source of protein and cash for poor rural livelihoods. ND mortality in these production systems is important and seriously disrupts benefits derived from it. This study undertook an African continental approach of ND epidemiology in backyard poultry. After a systematic literature review of studies published from 1980 to 2009, a meta-analysis of spatio-temporal patterns of serological prevalence and outbreak occurrence was performed. Average ND serological prevalence was estimated at 0·67 [95% confidence interval (CI) 0·58–0·75] in regions characterized by humid ecosystems, high human and poultry densities and low altitudes; 0·36 (95% CI 0·30–0·41) in dry ecosystems at intermediate altitude where human and poultry densities are low and 0·27 (95% CI 0·19–0·38) in mountain ecosystems where human and poultry densities are intermediate. In terms of seasonality, ND outbreaks occur mostly during the dry seasons in Africa, when environmental conditions are likely to be harshest for backyard poultry. In addition, a phylogeographical analysis revealed the regionalization of ND virus strains, their potential to evolve towards a higher pathogenicity from the local viral pool and suggests a risk for vaccine strains to provide new wild strains. These results present for the first time a continent-wide approach to ND epidemiology in Africa. More emphasis is needed for ND management and control in rural African poultry production systems.

Latin America has a high rate of community-associated infections caused by multidrug-resistant Enterobacteriaceae relative to other world regions. A review of the literature over the last 10 years indicates that urinary tract infections (UTIs) by Escherichia coli, and intra-abdominal infections (IAIs) by E. coli and Klebsiella pneumoniae, were characterized by high rates of resistance to trimethoprim/sulfamethoxazole, quinolones, and second-generation cephalosporins, and by low levels of resistance to aminoglycosides, nitrofurantoin, and fosfomycin. In addition, preliminary data indicate an increase in IAIs by Enterobacteriaceae producing extended-spectrum β-lactamases, with reduced susceptibilities to third- and fourth-generation cephalosporins. Primary-care physicians in Latin America should recognize the public health threat associated with UTIs and IAIs by resistant Gram-negative bacteria. As the number of therapeutic options become limited, we recommend that antimicrobial prescribing be guided by infection severity, established patient risk factors for multidrug-resistant infections, acquaintance with local antimicrobial susceptibility data, and culture collection.

Global climate change is expected to affect the frequency, intensity and duration of extreme water-related weather events such as excessive precipitation, floods, and drought. We conducted a systematic review to examine waterborne outbreaks following such events and explored their distribution between the different types of extreme water-related weather events. Four medical and meteorological databases (Medline, Embase, GeoRef, PubMed) and a global electronic reporting system (ProMED) were searched, from 1910 to 2010. Eighty-seven waterborne outbreaks involving extreme water-related weather events were identified and included, alongside 235 ProMED reports. Heavy rainfall and flooding were the most common events preceding outbreaks associated with extreme weather and were reported in 55·2% and 52·9% of accounts, respectively. The most common pathogens reported in these outbreaks were Vibrio spp. (21·6%) and Leptospira spp. (12·7%). Outbreaks following extreme water-related weather events were often the result of contamination of the drinking-water supply (53·7%). Differences in reporting of outbreaks were seen between the scientific literature and ProMED. Extreme water-related weather events represent a risk to public health in both developed and developing countries, but impact will be disproportionate and likely to compound existing health disparities.

We assessed the impact of Haemophilus influenzae type b (Hib) vaccination, introduced in France in early 1993, on the incidence of invasive Haemophilus influenzae (Hi) disease up to 2008. The incidence of Hi meningitis fell from 0·9/100 000 in 1991–1992 to 0·09/100 000 in 1996–2008, with a marked decline (96%) in children aged <5 years, including infants aged <3 months, from 12 to 0·4/100 000. The incidence of invasive Hi disease also decreased in children aged <15 years from 6 to 0·7/100 000, remained stable in the 15–64 years age group at about 0·5/100 000, and increased slightly from 2·0 to 2·4/100 000 in persons aged >64 years. No emergence of non-encapsulated or encapsulated non-vaccine serotypes was observed. These findings confirm the major direct impact of Hib vaccination on the incidence of Hi invasive disease in children and the indirect benefit of vaccination for infants too young to be vaccinated.

In 2011, a novel orthobunyavirus of the Simbu serogroup, the Schmallenberg virus (SBV), was discovered using a metagenomic approach. SBV caused a large epidemic in Europe in ruminants. As with related viruses such as Akabane virus, it appears to be transmitted by biting midges. Transplacental infection often results in the birth of malformed calves, lambs and goat kids. In more than 5000 farms in Germany, The Netherlands, Belgium, France, UK, Italy, Spain, Luxembourg, Denmark and Switzerland acute infections of adult ruminants or malformed SBV-positive offspring were detected, and high seroprevalences were seen in adult ruminants in the core regions in The Netherlands, Germany and Belgium. The discovery of SBV, the spread of the epidemic, the role of vectors, the impact on livestock, public health issues, SBV diagnosis and measures taken are described in this review. Lessons to be learned from the Schmallenberg virus epidemic and the consequences for future outbreaks are discussed.

The incidence, morbidity, and mortality associated with Clostridium difficile gastrointestinal infections has increased greatly over recent years, reaching epidemic proportions; a trend due, in part, to the emergence of hypervirulent and antibiotic-resistant strains. The need to identify alternative, non-antibiotic, treatment strategies is therefore urgent. The ability of bacteria in faecal matter transplanted from healthy individuals to displace pathogen populations is well recognized. Further, there is growing evidence that such faecal microbiota transplantation can be of benefit in a wide range of conditions associated with gut dysbiosis. Recent technical advances have greatly increased our ability to understand the processes that underpin the beneficial changes in bacterial community composition, as well as to characterize their extent and duration. However, while much of the research into faecal microbiota transplantation focuses currently on achieving clinical efficacy, the potential for such therapies to contribute to the transmission of infective agents also requires careful consideration.

Meningococcal disease is mostly endemic in Latin America, with periodic occurrences of outbreaks and epidemics over the last few decades. This literature review summarizes the available epidemiological data for this region between 1945 and 2010. Incidence rates and serogroup distribution differ from country to country and over time. Serogroups A, B, and C have all been major causes of meningococcal disease since the 1970s. In the last decade serogroups W135 and Y may now be emerging in certain countries, with serogroup A virtually disappearing. Although progress has been made in improving and coordinating the surveillance of invasive disease, the uniformity and quality of reported data reflect the fact that the current surveillance systems focus on passive rather than active reporting, hence the reliability of data may vary between countries. Consideration of vaccination policies to control meningococcal disease can only be made with a sufficient understanding of the changing epidemiology in the region.

Causal mechanisms of norovirus outbreaks are often not revealed. Understanding the transmission route (e.g. foodborne, waterborne, or environmental) and vehicle (e.g. shellfish or recreational water) of a norovirus outbreak, however, is of great public health importance; this information can facilitate interventions for an ongoing outbreak and regulatory action to limit future outbreaks. Towards this goal, we conducted a systematic review to examine whether published outbreak information was associated with the implicated transmission route or vehicle. Genogroup distribution was associated with transmission route and food vehicle, but attack rate and the presence of GII.4 strain were not associated with transmission route, food vehicle, or water vehicle. Attack rate, genogroup distribution, and GII.4 strain distribution also varied by other outbreak characteristics (e.g. setting, season, hemisphere). These relationships suggest that different genogroups exploit different environmental conditions and thereby can be used to predict the likelihood of various transmission routes or vehicles.

The influence of an immunosuppressive cytokine, interleukin-10 (IL-10), on the outcome of hepatitis C virus (HCV) infection has been increasingly reported recently. A number of polymorphisms appear to control the level of IL-10 production. Among them, −592C/A, −819C/T and −1082G/A in the IL-10 gene are three most studied single nucleotide polymorphisms. To provide a more definitive conclusion about their association with the risk of HCV infection, a meta-analysis was performed by combining and summarizing a total of 17 studies. A biological justification for the choice of genetic model was provided. The results indicated no significant association between these IL-10 polymorphisms and the susceptibility to HCV infection [–592C/A: odds ratio (OR) 0·99, 95% confidence interval (CI) 0·78–1·25; –819C/T: OR 0·90, 95% CI 0·69–1·18; –1082G/A: OR 1·34, 95% CI 0·90–2·00]. However, this analysis did not account for the possible risk modifications by other factors, such as ethnicity and virus persistence. Therefore, the effects of ethnicity and virus persistence were investigated using Bayesian meta-regression and subgroup analysis. Finally, an extended case-control association study was conducted in a Chinese population involving 1140 subjects. Both serum level and genotype data of IL-10 −1082G/A were determined. As a result, a low prevalence of G allele was observed. Significantly higher IL-10 production was observed in HCV patients, especially patients with the GG genotype.

Shigella is an important bacterial cause of infectious diarrhoea globally. The Shigella human challenge model has been used since 1946 for a variety of objectives including understanding disease pathogenesis, human immune responses and allowing for an early assessment of vaccine efficacy. A systematic review of the literature regarding experimental shigellosis in human subjects was conducted. Summative estimates were calculated by strain and dose. While a total of 19 studies evaluating nine strains at doses ranging from 10 to 1 × 1010 colony-forming units were identified, most studies utilized the S. sonnei strain 53G and the S. flexneri strain 2457T. Inoculum solution and pre-inoculation buffering has varied over time although diarrhoea attack rates do not appear to increase above 75–80%, and dysentery rates remain fairly constant, highlighting the need for additional dose-ranging studies. Expansion of the model to include additional strains from different serotypes will elucidate serotype and strain-specific outcome variability.

Asymptomatic carriage of gastrointestinal zoonoses is more common in people whose profession involves them working directly with domesticated animals. Subclinical infections (defined as an infection in which symptoms are either asymptomatic or sufficiently mild to escape diagnosis) are important within a community as unknowing (asymptomatic) carriers of pathogens do not change their behaviour to prevent the spread of disease; therefore the public health significance of asymptomatic human excretion of zoonoses should not be underestimated. However, optimal strategies for managing diseases where asymptomatic carriage instigates further infection remain unresolved, and the impact on disease management is unclear. In this review we consider the environmental pathways associated with prolonged antigenic exposure and critically assess the significance of asymptomatic carriage in disease outbreaks Although screening high-risk groups for occupationally acquired diseases would be logistically problematical, there may be an economic case for identifying and treating asymptomatic carriage if the costs of screening and treatment are less than the costs of identifying and treating those individuals infected by asymptomatic hosts.

Norovirus is a common cause of gastroenteritis in all ages. Typical infections cause viral shedding periods of days to weeks, but some individuals can shed for months or years. Most norovirus risk models do not include these long-shedding individuals, and may therefore underestimate risk. We reviewed the literature for norovirus-shedding duration data and stratified these data into two distributions: regular shedding (mean 14–16 days) and long shedding (mean 105–136 days). These distributions were used to inform a norovirus transmission model that predicts the impact of long shedders. Our transmission model predicts that this subpopulation increases the outbreak potential (measured by the reproductive number) by 50–80%, the probability of an outbreak by 33%, the severity of transmission (measured by the attack rate) by 20%, and transmission duration by 100%. Characterizing and understanding shedding duration heterogeneity can provide insights into community transmission that can be useful in mitigating norovirus risk.

Viral hepatitis is recognized as one of the most frequently reported diseases, and especially in China, acute and chronic liver disease due to viral hepatitis has been a major public health problem. The present study aimed to analyse and predict surveillance data of infections of hepatitis A, B, C and E in Wuhan, China, by the method of time-series analysis (MemCalc, Suwa-Trast, Japan). On the basis of spectral analysis, fundamental modes explaining the underlying variation of the data for the years 2004–2008 were assigned. The model was calculated using the fundamental modes and the underlying variation of the data reproduced well. An extension of the model to the year 2009 could predict the data quantitatively. Our study suggests that the present method will allow us to model the temporal pattern of epidemics of viral hepatitis much more effectively than using the artificial neural network, which has been used previously.

Infection of wild animals by bovine tuberculosis (bTB) is raising concern worldwide. This article reviews the current epidemiological situation, risk of emergence and control options at the wildlife–livestock–human interface in sub-Saharan Africa. In livestock, bTB has been confirmed in the majority of countries from all parts of the continent. Wildlife infection is confirmed in seven countries from southern and eastern Africa, apparently spreading in the southern Africa region. Mycobacterium bovis has been isolated from 17 wild mammal species, although only four are suspected to play a role as maintenance host. Zoonotic risks are a concern, but no direct spillover from wildlife to humans has been documented, and no case of bTB spillback from wildlife to livestock has been confirmed. In this paper we assess the main risk factors of bTB spillover at the wildlife–livestock–human interface and suggest several research themes which could improve the control of the disease in the African context.

Over 4 million patients suffer nosocomial infections annually in the European Union. This study aimed to estimate the healthcare burden associated with healthcare-associated infections (HAIs) following surgery in France, and explore the potential impact of infection control strategies and interventions on the clinical and economic burden of disease. Data on the frequency of HAIs were gathered from the 2010 Programme de Médicalisation des Systèmes d'Information (PMSI), and cost data were taken from the 2009 Echelle Nationale de Coûts à Méthodologie Commune (ENCC). It was estimated that 3% of surgical procedures performed in 2010 in France resulted in infection, resulting in an annual cost of €57 892 715. Patients experiencing a HAI had a significantly increased mortality risk (4·15-fold) and an increased length of hospital stay (threefold). Scenario analysis in which HAI incidence following surgery was reduced by 8% (based on a study of the effectiveness of triclosan-coated sutures), suggested that, annually, 20 205 hospital days and €4 588 519 could be saved. Analyses of 20% and 30% reductions in incidence (based on an estimate of the number of preventable nosocomial infections) suggested that annual savings of €11 548 057 and €17 334 696, respectively, could be made. New infection control interventions which reduce HAI incidence during hospitalization for surgery have the potential to provide valuable cost savings to healthcare providers.

West Nile virus (WNV) is a zoonotic arthropod-borne pathogen with continued geographical expansion in Europe. We present and evaluate data on the temporal, spatial and bird species focus of the WNV surveillance programme in dead wild birds in Great Britain (2002–2009). During this period all bird samples tested negative for WNV. Eighty-two per cent of the 2072 submissions occurred during the peak period of vector activity with 53% tested during April–July before human and equine infection would be expected. Samples were received from every county, but there was significant geographical clustering (nearest neighbour index=0·23, P<0·001). Over 240 species were represented, with surveillance more likely to detect WNV in resident bird species (92% of submissions) than migrants (8%). Evidence indicates that widespread avian mortality is not generally a reported feature of WNV in Europe and hence additional activities other than dead bird surveillance may maximize the ability to detect WNV circulation before the onset of human and equine infections.

We compared serotype distributions of Streptococcus pneumoniae isolates from patients aged <5 and ⩾5 years with invasive pneumococcal disease in New South Wales, Australia, and antibiotic susceptibilities of isolates from the <5 years age group only, before (2002–2004) and after (2005–2009) introduction of the 7-valent pneumococcal conjugate vaccine (PCV7). Overall, there were significant decreases in the mean annual number of referred isolates (770 vs. 515) and the proportion belonging to PCV7 serotypes (74% vs. 38%), but non-PCV7 serotypes, particularly 19A, increased (5% vs. 18%). All changes were more marked in the <5 years age group. Susceptibility testing of isolates from the <5 years age group showed variation in resistance between serotypes, but significant overall increases in penicillin non-susceptibility (23% vs. 31%), ceftriaxone resistance (2% vs. 12%) and multidrug resistance (4% vs. 7%) rates; erythromycin resistance fell (32% vs. 25%). Continued surveillance is needed to monitor changes following the introduction of 13-valent PCV in 2012.

Samples from different water sources (n = 396) were collected during 2009 and 2011. Wastewater (2–5 l) was purified by aluminium sulphate flocculation. Surface, ground and drinking waters (400–6400 l) were collected by filtration. Cryptosporidium oocysts and Giardia cysts were further concentrated by sucrose centrifugation. (Oo)cysts were identified by IFT (immunofluorescence test), DAPI (4′,6-diamidino-2-phenylindole) staining and DICM (difference interference contrast microscopy). Out of 206 wastewater samples, 134 (65·0%) were found to be positive for Giardia cysts and 64 (31·1%) for Cryptosporidium oocysts. Parasite numbers ranged from 0 to 2436 cysts/l and 0 to 1745 oocysts/l. Eight (4·2%) surface and drinking water samples (n = 190) were found to be positive for Giardia cysts (0–56000/100 l), and 18 (9·5%) for Cryptosporidium oocysts (2400/100 l). The purpose of this study was to establish the prevalence and concentrations of Giardia lamblia and Cryptosporidium spp. by detecting (oo)cysts from water samples. This study provides substantial evidence that G. lamblia cysts and Cryptosporidium spp. oocysts are able to enter and circulate in the aquatic environment with negative implications for public health.

This paper describes the practical use of social network diagrams in the management of an outbreak of Escherichia coli O157 (VTEC) in a primary school in London. The diagrams were created during the outbreak to establish the extent and nature of person-to-person transmission in the cases and their contacts. The diagrams supported a tailored public health action, and hence aided in the control of the outbreak. We conclude that for selected infectious diseases, social network diagrams can provide a valuable tool in the management of an outbreak.