Chagas' disease is an opportunistic infection in the setting of HIV/AIDS. The arrival of HIV-positive immigrants from endemic areas to non-endemic countries makes possible the detection of Chagas' disease in this group of patients. We describe the results of a screening programme conducted in the HIV-positive immigrant population arriving from endemic areas who attended the Tropical Medicine Unit of Hospital Universitario Central of Asturias during 2008. We determined anti-T. cruzi antibodies in all HIV patients arriving from endemic areas who were followed up. The ID-Chagas antibody test was used as a screening assay. The positive cases were confirmed with ELISA, IFAT and PCR. We analysed 19 HIV-positive immigrants, of which two (10·5%) had a positive antibody test for Chagas' disease confirmed. PCR was positive in both cases. There was no difference between the co-infected and the non-co-infected patients with respect to race, place of birth and residence, CD4+ cell count, and HIV viral load count. Direct microscopic examination of blood was negative in both positive cases. The positive patients were a man from Bolivia and woman from Paraguay. The overlap of HIV and T. cruzi infection occurs not only in endemic areas but also in non-endemic areas of North America and Europe where the diagnosis may be even more difficult due to low diagnostic suspicion. The implementation of screening programmes in this population group is needed for the early diagnostic of Chagas' disease.

The introduction of a centralized system for recording cattle movements in the UK has provided a framework for network-based models for disease spread. However, there are many types of non-reportable contacts between farms which may play a role in disease spread. The lack of real pathogen data with which to test network models makes it difficult to assess whether reported data adequately captures the risk-potential network between farms and improves the accuracy of disease forecasts. A novel multi-disciplinary approach is described whereby network-based models, built upon reported cattle movements and non-reportable local contacts between study farms, are parameterized using field data on bovine Staphylococcus aureus strains. Reported cattle movements were found to play a role in strain spread between farms, but other contacts via farm visitors were also correlated with strain distribution, suggesting that parameterizing contact networks using cattle-tracing data alone may not adequately capture the disease dynamics.

Newborns often present with skin conditions ranging from transient benign to severe. An occasional cause of neonatal exanthemic rash is infection due to Gram-positive bacteria, but Gram-negative infection is uncommon. We describe an outbreak of sepsis in 10 neonates over a 2-week period, caused by Klebsiella pneumoniae in a level III neonatal intensive care unit (NICU). Seven babies developed an exanthematous maculopapular rash. Molecular analysis by pulsed-field gel electrophoresis showed that all the babies with rash were infected by a single strain of K. pneumoniae which was distinct from the strain recovered from babies without rash.

We investigated the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage in a convenience sample of purposely selected populations of dogs, cats and horses in the Greater London area. Swabs from carriage sites were pooled, enriched and processed by standard bacteriological methods. The presence of nuc and mecA was confirmed for MRSA. Risk factors were investigated among veterinary treatment group animals using exact logistic regression analysis. Twenty-six (1·53%) MRSA carriers were identified in the 1692 animals (15/704 dogs, 8/540 cats, 3/152 horses). Animals presenting for veterinary treatment more frequently carried MRSA than healthy animals (OR 7·27, 95% CI 2·18–24·31, P<0·001). Concurrent carriage of non-MRSA coagulase-positive staphylococci was associated with MRSA carriage (OR 0·088, 95% CI 0·016–0·31, P<0·001); none of the other 13 putative risk factors was significant. MRSA carriage was rare in the selected companion animal populations. The absence of typical risk factors indicates that companion animals act as contaminated vectors rather than as true reservoirs.

The factors underlying the temporal dynamics of rubella outside of Europe and North America are not well known. Here we used 20 years of incidence reports from Mexico to identify variation in seasonal forcing and magnitude of transmission across the country and to explore determinants of inter-annual variability in epidemic magnitude in rubella. We found considerable regional variation in both magnitude of transmission and amplitude of seasonal variation in transmission. Several lines of evidence pointed to stochastic dynamics as an important driver of multi-annual cycles. Since average age of infection increased with the relative importance of stochastic dynamics, this conclusion has implications for the burden of congenital rubella syndrome. We discuss factors underlying regional variation, and implications of the importance of stochasticity for vaccination implementation.

In France, haemorrhagic fever with renal syndrome (HFRS) is endemic along the Belgian border. However, this rodent-borne zoonosis caused by the Puumala virus has recently spread south to the Franche-Comté region. We investigated the space–time distribution of HFRS and evaluated the influence of environmental factors that drive the hantavirus reservoir abundance and/or the disease transmission in this area. A scan test clearly indicated space–time clustering, highlighting a single-year (2005) epidemic in the southern part of the region, preceded by a heat-wave 2 years earlier. A Bayesian regression approach showed an association between a variable reflecting biomass (normalized difference vegetation index) and HFRS incidence. The reasons why HFRS cases recently emerged remain largely unknown, and climate parameters alone do not reliably predict outbreaks. Concerted efforts that combine reservoir monitoring, surveillance, and investigation of human cases are warranted to better understand the epidemiological patterns of HFRS in this area.

We evaluated the incidence of varicella-zoster virus (VZV) infections, including herpes zoster (HZ), and investigated the associated risk factors for HZ and compared lymphocyte subsets of these patients at 1, 3 and 6 months following haematopoietic stem cell transplantation (HSCT) in a case-control study in children and adolescents. The incidence of HZ infection at the first year after HSCT was 17/125 (13·6%). The cumulative incidence of HZ infection was 22/125 (17·6%). Sixteen (73%) cases with HZ and 11 (32%) cases in the control group had a diagnosis of malignant disorder. No significant difference was noted between the HZ group and the control group in absolute lymphocyte number and subsets (except WBC) at the pre-transplant evaluation. Pre-transplant WBC count was statistically lower in the HZ group (P<0·05). The CD4/CD8 ratios were lower in the HZ group during the first 6 months after HSCT, and the decrease was statistically significant at 6 months compared to the control group. In conclusion, patients undergoing HSCT for a malignant disorder had a significantly higher risk of VZV infection than those with non-malignant disorders and pretransplant donor characteristics were not helpful in predicting risk of post-transplant VZV infection.

Evaluation of antimalarial efficacy is difficult because recurrent parasitaemia can be due to recrudescence or re-infection. PCR is used to differentiate between recrudescences and re-infections by comparing parasite allelic variants before and after treatment. However, PCR-corrected results are susceptible to misclassification: false positives, due to re-infection by the same variant present in the patient before treatment; and false negatives, due to variants that are present but too infrequent to be detected in the pre-treatment PCR, but are then detectable post-treatment. This paper aimed to explore factors affecting the probability of false positives and proposes a Monte Carlo uncertainty analysis to account for both types of misclassification. Higher levels of transmission intensity, increased multiplicity of infection, and limited allelic variation resulted in more false recrudescences. The uncertainty analysis exploits characteristics of study data to minimize bias in the estimate of efficacy and can be applied to areas of different transmission intensity.

In July and August 2007, a giardiasis outbreak affected attendees of a private recreational camp in California. Twenty-six persons had laboratory-confirmed giardiasis; another 24 had giardiasis-like illness with no stool test. A retrospective cohort study determined that showering was associated with illness (adjusted odds ratio 3·1, 95% confidence interval 1·1–9·3). Two days before the outbreak began, the camp had installed a slow-sand water filtration system that included unsterilized sand. Review of historical water-quality data identified substantially elevated total coliform and turbidity levels in sand-filtered spring water used for showering during the suspected exposure period. Unfiltered spring water tested at the same time had acceptable coliform and turbidity levels, implicating the filtration system as the most likely contamination source. To prevent waterborne illness, slow-sand water filtration systems should use sterilized sand, and slow-sand-filtered water should not be used for any purpose where inadvertent ingestion could occur until testing confirms its potability.

We used a mathematical model to describe a regional outbreak and extrapolate the underlying health-service resource needs. This model was designed to (i) estimate resource gaps and quantities of resources needed, (ii) show the effect of resource gaps, and (iii) highlight which particular resources should be improved. We ran the model, parameterized with data from the 2009 H1N1v pandemic, for two provinces in Thailand. The predicted number of preventable deaths due to resource shortcomings and the actual resource needs are presented for two provinces and for Thailand as a whole. The model highlights the potentially huge impact of health-system resource availability and of resource gaps on health outcomes during a pandemic and provides a means to indicate where efforts should be concentrated to effectively improve pandemic response programmes.

Phylogenetic analysis was performed on the haemagglutinin and neuraminidase subtype N2 genes of low-pathogenic avian influenza viruses (LPAIVs) detected in Ireland between 2003 and 2007. Nucleotide sequences were compared to previously published sequences from the National Centre for Biotechnology Information. Sequences from viruses of the same subtype isolated in different years were compared to examine the possibility that LPAIVs may have been maintained in Ireland from year to year. All viruses had closest identity with published sequences of European lineage, supporting the conclusion that LPAIVs had been introduced to Ireland by dabbling ducks that had migrated from Europe. The data suggested that different subtypes of virus had been introduced each year. However, there was evidence that some LPAIVs may have been maintained in the sedentary waterfowl population for consecutive seasons. Furthermore, almost identical H6 and H10 sequences with different N types were found in isolates from the same season, suggesting that reassortment had occurred.

This population-based cohort study aimed to investigate the incidence and relative hazard of renal and perinephric abscess (RA) in the diabetic population in Taiwan. More than a half million diabetic patients and sex- and age-matched controls were identified from the 1997 Taiwan National Health Insurance data and were linked to in-patient claims from 1997 to 2007. Person-year approach with Poisson assumption was used to estimate the incidence density (ID) of RA. The hazard ratios (HRs) of hospitalization due to RA in relation to diabetes were analysed using a Cox proportional hazard model. The ID for the diabetic and control subjects was 4·6 and 1·1/10 000 person-years, respectively, in 11 years of follow-up, representing an adjusted HR of 3·81 (95% confidence interval 3·44–4·23). This study confirmed the association of diabetes with RA, and argued that more aggressive urological care should be administered to diabetic patients.

Foodborne zoonoses have a major impact on public health in China. Its booming economy and rapid socioeconomic changes have affected food production, food supplies and food consumption habits, resulting in an increase in the number of outbreaks of foodborne zoonoses. Both emerging and re-emerging foodborne zoonoses have attracted increasing national and international attention in recent years. This paper briefly reviews the main foodborne zoonoses that have had a major impact on public health over the last 20 years in China. The major causative microorganisms, including foodborne bacteria, parasites and viruses, are discussed. The prevention and control of foodborne zoonoses are difficult challenges in China. The information provided here may aid the development of effective prevention and control strategies for foodborne zoonoses.

Most mathematical models of sexually transmitted infections (STIs) assume that infected individuals become susceptible to re-infection immediately after recovery. This paper assesses whether extending the standard model to allow for temporary immunity after recovery improves the correspondence between observed and modelled levels of STI prevalence in South Africa, for gonorrhoea, chlamydial infection and trichomoniasis. Five different models of immunity and symptom resolution were defined, and each model fitted to South African STI prevalence data. The models were compared in terms of Bayes factors, which show that in the case of gonorrhoea and chlamydial infection, models that allow for immunity provide a significantly better fit to STI prevalence data than models that do not allow for immunity. For all three STIs, estimates of the impact of changes in STI treatment and sexual behaviour are significantly lower in models that allow for immunity. Mathematical models that do not allow for immunity could therefore overestimate the effectiveness of STI interventions.

This study aimed to investigate the spatial clustering and dynamic dispersion of dengue incidence in Queensland, Australia. We used Moran's I statistic to assess the spatial autocorrelation of reported dengue cases. Spatial empirical Bayes smoothing estimates were used to display the spatial distribution of dengue in postal areas throughout Queensland. Local indicators of spatial association (LISA) maps and logistic regression models were used to identify spatial clusters and examine the spatio-temporal patterns of the spread of dengue. The results indicate that the spatial distribution of dengue was clustered during each of the three periods of 1993–1996, 1997–2000 and 2001–2004. The high-incidence clusters of dengue were primarily concentrated in the north of Queensland and low-incidence clusters occurred in the south-east of Queensland. The study concludes that the geographical range of notified dengue cases has significantly expanded in Queensland over recent years.

The worldwide increase of resistant S. pneumoniae is a growing clinical problem. In several countries, a more restrictive use of penicillin has been promoted in hope of slowing the rates of resistant pneumococci. However, the consequences of such an action on pneumococcal population dynamics are not fully understood. Thus, a network model was constructed to assess the impacts of penicillin consumption and between-strain competition on the spread of penicillin non-susceptible pneumococci. Model simulations suggest that the age distribution for carriage of penicillin non-susceptible pneumococci, in contrast to susceptible pneumococci, is affected by penicillin consumption. Furthermore, it appears extremely difficult to reduce the incidence of penicillin non-susceptible pneumococci by simply controlling penicillin consumption, assuming that reduced penicillin susceptibility does not confer a fitness cost for the organism. A more judicious use of penicillin together with control measures are in that case required to manage penicillin resistance in pneumococci.

Supplementary immunization activities (SIAs) are important in achieving high levels of population immunity to measles virus. Using data from a 2006 survey of measles vaccination in Lusaka, Zambia, we developed a model to predict measles immunity following routine vaccination and SIAs, and absent natural infection. Projected population immunity was compared between the current programme and alternatives, including supplementing routine vaccination with a second dose, or SIAs at 1-, 2-, 3-, 4- and 5-year intervals. Current routine vaccination plus frequent SIAs could maintain high levels of population immunity in children aged <5 years, even if each frequent SIA has low coverage (e.g. ⩾72% for bi-annual 60% coverage SIAs vs. ⩾69% for quadrennial 95% coverage SIAs). A second dose at 12 months with current coverage could achieve 81% immunity. Circulating measles virus will only increase population immunity. Public health officials should consider frequent SIAs when resources for a two-dose strategy are unavailable.

Weekly (August 2003–December 2008) numbers of five common paediatric diseases and the incidence of respiratory viruses were obtained from a children's hospital in Singapore and correlated with climate data using multivariate time-series techniques. Upper respiratory tract infections were positively correlated with the incidences of influenza A, B, respiratory syncytial virus (RSV) and parainfluenza viruses (types 1–3 combined). Lower respiratory tract infections were positively correlated with only the incidence of RSV. Both upper and lower respiratory tract infections were negatively correlated with relative humidity. Asthma admissions were negatively correlated with maximum temperature and positively correlated with the incidence of influenza B and increasing hours of sunshine. Although sporadic cases of adenovirus infection were identified, not enough cases were available for a more detailed analysis. Gastroenteritis and urinary tract infections, included as control diseases, were not correlated significantly with any climate parameters. These correlations are compatible with current understanding of respiratory virus survival under certain climate conditions and may assist the prediction of disease burdens and hospital resource planning in such tropical environments.

This study determined the carriage rate and serotype distribution of group B Streptococcus (GBS) in women of child-bearing age in the southern region of Ireland. A total of 2000 vaginal swabs collected in two periods in 2004 and 2006 were examined and revealed a GBS carriage rate of 16·1%. Serotyping of isolates showed that serotypes Ia, II, III, IV, and V were the most prevalent. A high prevalence of serotype IV was found, increasing from 7·6% to 15·2% between 2004 and 2006. Random amplified polymorphic DNA analysis demonstrated considerable genetic heterogeneity in the serotype IV isolates. This serotype should be considered for inclusion in potential vaccines for use in Ireland.

The annual number of episodes of clinical gastroenteritis caused by Campylobacter spp. in The Netherlands is estimated to be 75 000, i.e. once per 200 person life-years. This number is based on extrapolation of culture results from population-based studies. The number of culture-confirmed cases of Campylobacter infection peaks in the first 3 years of life and again between the ages of 20 and 25 years. The seroepidemiology of Campylobacter describes the relationship between age and exposure to Campylobacter and reflects both symptomatic and asymptomatic infections. Using a validated ELISA system, antibodies to Campylobacter were measured in an age-stratified sample (n=456) of the PIENTER serum collection of the Dutch general population. The seroprevalence of Campylobacter IgG antibodies increased with age, reaching almost 100% at age 20 years. Antibody levels steadily increased with age until young adulthood, suggesting repeated exposure to Campylobacter. In conclusion, seroepidemiological data demonstrated repeated exposures to Campylobacter throughout life, most of which do not lead to clinical symptoms. From young adulthood, >95% of the population in The Netherlands had serological evidence for exposure to Campylobacter.