New Zealand has a higher reported incidence of cryptosporidiosis and giardiasis than most other developed countries. This study aimed to describe and compare the epidemiology of these infections in New Zealand, to better understand their impact on public health and to gain insight into their probable modes of transmission. We analysed cryptosporidiosis and giardiasis notification data for a 10-year period (1997–2006). Highest rates for both diseases were in Europeans, children aged 0–5 years, and those living in low-deprivation areas. Cryptosporidiosis distribution was consistent with mainly farm animal (zoonotic) reservoirs. There was a dose–response relationship with increasing grades of rurality, marked spring seasonality, and positive correlation with farm animal density. Giardiasis distribution was consistent with predominantly human (anthroponotic) reservoirs, with an important contribution from overseas travel. Further research should focus on methods to reduce transmission of Cryptosporidium in rural areas and on reducing anthroponotic transmission of Giardia.

In Atlantic Canada, the traditional risk factor for acquisition of Q fever infection has been exposure to infected parturient cats or newborn kittens. In this study we describe the first case of Q fever in Nova Scotia acquired as a result of direct exposure to sheep. A serosurvey of the associated flock was undertaken using an indirect immunofluorescence assay (IFA) testing for antibodies to phase I and phase II Coxiella burnetii antigens. This serosurvey revealed that 23 of 46 sheep (50%) were seropositive for the phase II antibody. Four of these sheep had titres of 1:64 including three nursing ewes, one of which had delivered two lambs that died shortly after delivery. Only one ewe had phase I antibodies but had the study's highest phase II antibody titre (1:128). Molecular studies using polymerase chain reaction (PCR) failed to detect C. burnetii DNA in any of the milk specimens.

Recently, human cases of nephropathia epidemica (NE) due to Puumala virus infection in Europe have increased. Following the hypothesis that high reservoir host abundance induces higher transmission rates to humans, explanations for this altered epidemiology must be sought in factors that cause bank vole (Myodes glareolus) abundance peaks. In Western Europe, these abundance peaks are often related to high tree seed production, which is supposedly triggered by specific weather conditions. We evaluated the relationship between tree seed production, climate and NE incidence in Belgium and show that NE epidemics are indeed preceded by abundant tree seed production. Moreover, a direct link between climate and NE incidence is found. High summer and autumn temperatures, 2 years and 1 year respectively before NE occurrence, relate to high NE incidence. This enables early forecasting of NE outbreaks. Since future climate change scenarios predict higher temperatures in Europe, we should regard Puumala virus as an increasing health threat.

In March 2002, an outbreak of Salmonella Enteritidis (SE) infections occurred at a convention centre in Dallas, Texas and continued for 6 weeks. We conducted epidemiological studies, obtained clinical and environmental cultures, and interviewed employees to identify risk factors for infection. From 17 March–25 April 2002, the implicated hotel kitchen catered 41 multi-day conferences attended by 9790 persons. We received 617 illness reports from residents of 46 states. Sauces or items served with sauces were implicated in three cohort studies. SE phage-type 8 was identified as the agent. Eleven food service employees, including one who prepared sauces and salsa, had stool cultures that yielded SE. Although the original source was not determined, prolonged transmission resulted in the largest food handler-associated outbreak reported to date, affecting persons from 46 US states. Transmission ended with implementation of policies to screen food handlers and exclude those whose stool cultures yielded salmonellas.

In vitro tests have been developed for the diagnosis of tuberculosis (TB) infection. The objective was to analyse latent TB infection in drug and alcohol abusers through two interferon-γ techniques. One hundred and thirty-nine patients were admitted between February 2006 and May 2007. Mean age was 39·8 years [31% HIV positive]. The enzyme immunoassay (EIA) and enzyme-linked immunospot (ELISPOT) interferon-γ assays were positive in 34% of patients with an agreement of 83% (κ=0·63). Tuberculin skin test (TST) was positive in 29% of patients and the agreement of TST with EIA and ELISPOT interferon-γ assays was 85% (κ=0·62) and 83% (κ=0·57), respectively. Almost 50% of patients with history of TB had a positive in vitro test. In conclusion, we observed a high prevalence of latent TB and good agreement between the new in vitro tests that otherwise may continue to be positive long after developing TB disease.

Ross River virus (RRV) infection is the most common notifiable vector-borne disease in Australia, with around 6000 cases annually. This study aimed to examine the relationship between climate variability and notified RRV infections in the Riverland region of South Australia in order to set up an early warning system for the disease in temperate-climate regions. Notified data of RRV infections were collected by the South Australian Department of Health. Climatic variables and monthly river flow were provided by the Australian Bureau of Meteorology and South Australian Department of Water, Land and Biodiversity Conservation over the period 1992–2004. Spearman correlation and time-series-adjusted Poisson regression analysis were performed. The results indicate that increases in monthly mean minimum and maximum temperatures, monthly total rainfall, monthly mean Southern Oscillation Index and monthly flow in the Murray River increase the likelihood, but an increase in monthly mean relative humidity decreases the likelihood, of disease transmission in the region, with different time-lag effects. This study demonstrates that a useful early warning system can be developed for local regions based on the statistical analysis of readily available climate data. These early warning systems can be utilized by local public health authorities to develop disease prevention and control activities.

On 24–25 October 2005 a cluster of five haemolytic uraemic syndrome (HUS) cases was reported in southwest France. An investigation was undertaken to identify the outbreak source and implement control measures. Cases were defined as individuals with HUS or diarrhoea with isolation of Escherichia coli O157:H7 in stools or a positive antibody response to E. coli O157 lipopolysaccharide, resident in southwest France with symptom onset after 19 September 2005. Sixty-nine identified patients had symptom onset between 5 October and 3 November 2005, including 17 cases of HUS. One brand of frozen beef burgers produced on 22 August 2005 was consumed by all patients in the week before symptom onset. E. coli O157:H7 strains from patients, patients' burgers and the manufacturing plant were genetically related. This is the largest community-wide outbreak of E. coli O157:H7 in France to date and the first associated with consumption of contaminated frozen beef burgers.

Human bocavirus (HBoV) was recently identified in respiratory samples from patients with acute respiratory infections and has been reported in different regions of the world. To the best of our knowledge, HBoV has never been reported in respiratory infections in Brazil. Nasopharyngeal aspirates were collected from patients aged <5 years hospitalized in 2005 with respiratory infections in Ribeirão Preto, southeast Brazil, and tested by polymerase chain reaction (PCR) for HBoV. HBoV-positive samples were further tested by PCR for human respiratory syncytial virus, human metapneumovirus, human coronaviruses 229E and OC43, human influenza viruses A and B, human parainfluenza viruses 1, 2 and 3, human rhinovirus and human adenovirus. HBoV was detected in 26/248 (10·5%) children of which 21 (81%) also tested positive for other respiratory viruses. Despite the high rates of co-infections, no significant differences were found between HBoV-positive patients with and without co-infections with regard to symptoms.

Reduction in wildlife populations is a common method for the control of livestock infections which have wildlife hosts, but its success is dependent on the characteristics of the infection itself, as well as on the spatial and social structure of the wildlife host. Paratuberculosis (Mycobacterium avium subsp. paratuberculosis; Map) is a widespread and difficult infection to control in livestock populations and also has possible links to Crohn's disease in humans. Rabbits have recently been identified as a key wildlife species in terms of paratuberculosis persistence in the environment and risk to the wider host community, including cattle. Here we use a spatially explicit stochastic simulation model of Map dynamics in rabbit populations to quantify the effects of rabbit population control on infection persistence. The model parameters were estimated from empirical studies of rabbit population dynamics and rabbit-to-rabbit routes of Map transmission. Three rabbit control strategies were compared: single unrepeated population reductions based on removing individual animals; single unrepeated population reductions based on removal of entire social groups; and repeated annual population reductions based on removing individual animals. Unrealistically high rabbit culls (>95% population reduction) are needed if infection is to be eradicated from local rabbit populations with a single one-off population reduction event, either of individuals or social groups. Repeated annual culls are more effective at reducing the prevalence of infection in rabbit populations and eradicating infection. However, annual population reductions of >40% are required over extended periods of time (many years). Thus, using an approach which is both highly conservative and parsimonious with respect to estimating lower bounds on the time to eradicate the infection, we find that Map is extremely persistent in rabbit populations and requires significant and prolonged effort to achieve control.

This study aimed to identify risk factors and assess the impact of coincidental antibiotic therapy on carriage of Streptococcus pneumoniae. Index children from birth to 3 years and their households were recruited from primary health-care registers in four UK general practices. Nasopharyngeal swabs were taken monthly from study participants ten times between October 2001 and July 2002. Multilevel random-effect models were used to adjust for statistical dependence between repeated measurements and family clustering of carriage. Carriage results were available for 3753 swabs from 489 individuals in 121 families. Crude prevalence of carriage was 25%. On multivariable analysis, risk of carriage was reduced by antibiotic use the previous month [odds ratio (OR) 0·34, 95% confidence interval (CI) 0·22–0·52], but increased if a child attended day care for >20 h per week (OR 2·52, 95% CI 1·41–4·52). Taking antibiotics significantly reduces the risk of carriage the following month in a setting with a low prevalence of pneumococcal antimicrobial resistance.

We obtained a list of all reported cases of haemorrhagic fever with renal syndrome (HFRS) in Shenyang, China, during 1990–2003, and used GIS-based scan statistics to determine the distribution of HFRS cases and to identify key areas and periods for future risk-factor research. Spatial cluster analysis suggested three areas were at increased risk for HFRS. Temporal cluster analysis suggested one period was at increased risk for HFRS. Space–time cluster analysis suggested six areas from 1995 to 1996 and four areas from 1998 to 2003 were at increased risk for HFRS. We also discussed the likely reasons for these clusters. We conclude that GIS-based scan statistics may provide an opportunity to classify the epidemic situation of HFRS, and we can pursue future investigations to study the likely factors responsible for the increased disease risk based on the classification.

On 30 May 2006, township S in Sichuan Province, China, reported an outbreak of hepatitis A (HA) in students who had recently received HA vaccine. The concern was raised that the vaccine had caused the outbreak. We attempted to identify the source of infection and mode of transmission. A HA case was defined as onset of jaundice or anorexia since 1 April 2006 with a twofold elevation of alanine aminotransferase (ALT) and anti-HA virus-IgM in a resident of or visitor to the township. Exposures to vaccine and snacks of 90 case-students to those of 107 control-students were compared. Thirty-four per cent of cases ate ice slush compared to 4·7% of controls (OR 4·1), and 51% of cases ate snow cones compared to 17% of controls (OR 8·3). The ice snacks were made with well water. HA virus RNA was detected by reverse transcription–polymerase chain reaction from patients' blood and well water. Untreated well water poses important dangers to the public in areas where piped, potable water is available.

The aim of this paper is to investigate local spatial dependency with regard to Salmonella seropositivity in data from the Danish swine salmonellosis control programme and its application in informing surveillance strategies. We applied inhomogeneous and observed-difference K-function estimation, and geo-statistical modelling to data from the Danish swine salmonellosis control programme. Slaughter-pig farm density showed large variation at both the country-wide and local level in Denmark (median 0·23, range 0·02–0·47 farms/km2). The spatial distribution of pig farms followed a random inhomogeneous Poisson process but was not aggregated. We found evidence for aggregation of Salmonella case farms over that of all farms at distances of up to 6 km and semivariogram analyses of Salmonella seropositivity revealed spatial dependency between pairs of farms up to 4 km apart. The strength of the spatial dependency was positively associated with slaughter-pig farm density. We proposed sampling more intensively those farms within a 4 km radius of farms that were identified with a high Salmonella status, and reduced sampling of farms that are within this radius of ‘Salmonella-free’ farms. Our approach has the potential to optimize sampling strategies while maintaining consumer confidence in food safety and also has potential to be used for other zoonotic disease surveillance systems.

The importance of carrier animals (those in whom virus persists after recovery from disease or acute infection) and their potential role in the spread of disease remain open questions within foot-and-mouth disease epidemiology. Using simple probabilistic models we attempt to quantify the effect of emergency vaccination – and especially the time of application – on the likely number of such animals, using data from challenge experiments on both cattle and sheep to determine the probability of persistence in diseased and subclinically infected animals. We show that the number of persistently infected animals in a group is predominantly determined by the number of animals initially infected on premises – the high variability of which ultimately limits the accuracy of any predictions of carrier numbers based upon transmission models. Furthermore, results suggest that, within a cattle herd, carrier numbers may be increased if challenge occurs shortly after vaccination. We show that the quality of inspection is the principal factor influencing whether or not carrier herds occur and that, by reducing clinical signs, the application of vaccination in regularly checked stock also results in an increase in undetected persistently infected animals. Where clinical detection would be poor regardless of the use of vaccination (i.e. particularly in sheep), vaccination will result in a reduction in the probability of a group containing undetected carriers: otherwise there is a benefit only if vaccination is applied sufficiently far in advance of any challenge. The implications of the results for serosurveillance are discussed, including the requisite test sensitivity and practices for successful implementation.

Tri-County Health Department investigated an outbreak of cryptosporidiosis linked to a community swimming pool. A cohort study was conducted in 37 persons who were invited to the pool party; 12 (57%) of 21 attendees had primary cryptosporidiosis infection. Risk factors for illness included swimming, getting water in mouth, and swallowing water. The pool met chlorination guidelines and used UV light irradiation, a supplemental disinfection technology that inactivates Cryptosporidium. A follow-up survey of the cohort was completed 7–8 weeks after the pool party; four (25%) of 16 non-attendees had secondary cryptosporidiosis infection. The median duration of illness, including patients with recurring symptoms, was 26 days. Clinical response rate to nitazoxanide, a therapeutic agent, was 67%. This study is unique because it describes a cryptosporidiosis outbreak from a well-maintained community swimming pool using supplemental disinfection. It also reports information on disease burden and treatment response.

The purpose of the present study was to identify Echinococcus multilocularis infection in follow-up of 95 subjects initially seropostive by Emc-ELISA or Emf-ELISA antibody assays and to compare the utility of these assays with specific Em2plus-ELISA and ultrasound screening for E. multilocularis infection. At follow-up seven subjects were seropositive with both methods, while three were seropositive only with Emc-ELISA and 11 only with Emf-ELISA. All subjects were seronegative with Em2plus-ELISA. There were no manifestations of E. multilocularis infestation by ultrasonographic screening. Seropositivity on Emc-ELISA and Emf-ELISA screening tests does not appear to correlate with manifest alveolar echinococcosis identified by ultrasound. A recommendation for further follow-up of subjects found to be seropositive with Emc-ELISA and Emf-ELISA but with no sonographic evidence of disease is not justified at this time.

Cytomegalovirus (CMV) seroprevalence was determined in 9343 first-time New Zealand blood donors between 2003 and 2006. Of 39 960 current seropositive donors the proportion testing seropositive more than 12 months previously was calculated. Overall, seroprevalence declined from 66·1% [95% confidence interval (CI) 64·1–68·1] in 2003 to 60·6% (95% CI 58·5–62·6) in 2006. Nevertheless, these rates are significantly higher than the 47% overall seroprevalence found in a 1988 study. Seroprevalence was higher in females than males and in older than in younger age groups in all four years examined. Ethnicity appeared to be related to seroprevalence with the highest rates found in Pacific Islanders (93·2%) and the lowest in Caucasians (54·8%). At least 38 242/39 960 (95·7%) seropositive donors were found to have seroconverted more than 12 months previously. Recent evidence suggests that such ‘remote’ seroconverters may pose a much lower risk of transfusion-transmitted CMV infection than recently infected seroconverting, but seronegative, blood donors.

Young children account for a large proportion of reported Yersinia enterocolitica infections in Sweden with a high incidence compared with other gastrointestinal infections, such as salmonellosis and campylobacteriosis. A case-control study was conducted to investigate selected risk factors for domestic sporadic yersiniosis in children aged 0–6 years in Sweden. In total, 117 cases and 339 controls were included in the study. To minimize exclusion of observations due to missing data a multiple non-parametric imputation technique was used. The following risk factors were identified in the multivariate analysis: eating food prepared from raw pork products (OR 3·0, 95% CI 1·8–5·1) or treated sausage (OR 1·9, 95% CI 1·1–3·3), use of a baby's dummy (OR 1·9, 95% CI 1·1–3·2) and contact with domestic animals (OR 2·0, 95% CI 1·2–3·4). We believe that the importance of Y. enterocolitica infection in children has been neglected and that results from this study can be used to develop preventive recommendations.