Is the major increase in notified campylobacteriosis in New Zealand real?

Comparative prevalence and diversity of Campylobacter jejuni strains in water and human beings over a 1-year period in southwestern Alberta, Canada

Campylobacter jejuni was isolated from diarrheic people, river water (Oldman River watershed), wastewater, and drinking water over a 1-year period in southwestern Alberta (2008-2009). High rates of campylobacteriosis were observed during the study period (≥115 cases/100K). Infections occurred throughout the year, with a peak in late summer and early autumn. The majority of infections occurred in people living in Lethbridge. Campylobacter jejuni was not isolated from municipal drinking water. In contrast, the bacterium was isolated from untreated and treated wastewater, and river water (all sites). There were no correlations between C. jejuni recovery/detection from water and river flow rates, water turbidity, or fecal coliforms. Campylobacter jejuni recovery from water did not correspond with the peak periods of campylobacteriosis. The bacterium was most commonly isolated downstream of wastewater outfalls; waterfowl congregated at these sites, particularly during the winter months. A comparison of subtypes from people and water revealed that the vast majority of subtypes in water did not correspond to subtypes recovered from diarrheic people, and were linked to waterfowl and other non-human animal sources. We conclude that water-borne C. jejuni did not contribute significantly to the high rates of campylobacteriosis observed in people during the study period.

Prevalence and Antibiotic Resistance of Campylobacter spp. in Urban and Rural Black-Headed Gulls Chroicocephalus ridibundus

We investigate the role of black-headed gulls (Chroicocephalus ridibundus), an omnivorous species that is among the most likely wild bird candidates for transmission of zoonotic agents, as a potential reservoir of Campylobacter spp. Colonies with different anthropogenic pressures were studied to examine differences in exposure to sources of Campylobacter between rural and urban birds. We recorded Campylobacter spp. in 4.87% of adult black-headed gulls and 2.22% of their chicks after analysing 1036 cloacal swabs collected over two breeding seasons in three colonies in northern Poland. Campylobacter jejuni was found most frequently (85.72%), and Campylobacter lari and Campylobacter coli were much scarcer. Prevalence of Campylobacter did not differ significantly between black-headed gulls breeding in urban (4.27%) and rural (3.80%) habitats. Almost all isolates from chicks and adults were susceptible to azithromycin (97.62%) and erythromycin (95.24%), but fewer to tetracycline (50.00%) and ciprofloxacin (47.62%). Campylobacter prevalence was unrelated to the date of sampling. Our study indicates that black-headed gulls are carriers of resistant to antibiotics Campylobacter and they can contaminate natural waterbodies with their faeces, which poses a threat to human and farm animal health.

Rates of fluoroquinolone resistance in domestically acquired Campylobacter jejuni are increasing in people living within a model study location in Canada

Antimicrobial resistance was evaluated in Campylobacter jejuni isolated from 1291 diarrheic people over a 15-year period (2004-2018) in southwestern Alberta, a model location in Canada with a high rate of campylobacteriosis. The prevalence of resistance to chloramphenicol, clindamycin, erythromycin, and gentamicin was low during the examination period (≤4.8%). Resistance to tetracycline remained consistently high (41.6%-65.1%), and resistance was primarily conferred by plasmid-borne tetO (96.2%). Resistance rates to ciprofloxacin and nalidixic acid increased substantially over the examination period, with a maximal fluoroquinolone resistance (FQR) prevalence of 28.9% in 2016. The majority of C. jejuni isolates resistant to ciprofloxacin (93.9%) contained a C257T single nucleotide polymorphism within the gyrA chromosomal gene. Follow up with infected people indicated that the observed increase in FQR was primarily due to domestically acquired infections. Moreover, the majority of FQ-resistant C. jejuni subtypes (82.6%) were endemic in Canada, primarily linked to cattle and chicken reservoirs; 18.4% of FQ-resistant isolates were assigned to three subtypes, predominantly associated with cattle. Study findings indicate the need to prioritize FQR monitoring in C. jejuni infections in Canada and to elucidate the dynamics of the emergence and transmission of resistant C. jejuni strains within and from cattle and chicken reservoirs.

Effect of a direct-fed microbial and prebiotic on performance and intestinal histomorophology of turkey poults challenged with Salmonella and Campylobacter

Salmonella and Campylobacter are leading human foodborne pathogens commonly associated with poultry and poultry products, and several methods to control these pathogens have been applied to poultry production. This study was conducted to evaluate the effect of CALSPORIN, (CSP), a direct-fed microbial (DFM), and yeast cell wall (Saccharomyces cervisiae, IMW50, a mannanoligosaccharide (MOS)-based prebiotic, on performance, levels of Salmonella and Campylobacter in the feces, and intestinal histomorphometry in turkey poults. A 21-day battery cage study was conducted using 4 dietary treatments, including: an unsupplemented basal diet (corn and soybean-based) as negative control (NC); basal diet supplemented with 0.05% DFM; basal diet supplemented with 0.05% MOS; and basal diet supplemented with 0.05% mixture of DFM and MOS at equal proportions. Female Large White turkey poults (n = 336) were randomly distributed in 6 electrically-heated battery cages with 4 treatments and 12 replicates per treatment (7 poults per replicate pen). The first 16 pens were not inoculated with bacteria, while poults in pens 17 to 32 were orally challenged at day 7 with 105 CFU Salmonella Heidelberg and the poults in pens 33 to 48 were orally challenged at day 7 with 105 CFU Campylobacter jejuni. Feed consumption, body weight, and feed conversion ratio were measured weekly and at the end of the experiment. At day 21, fresh fecal samples from each pen were collected for Salmonella and Campylobacter enumeration and ileal tissue samples were collected from 1 bird per pen for histomorphology examination. DFM and MOS supplementation was accompanied with reduced levels of Salmonella shed by the treated birds compared to the control group, and with increased body weight (P ≤ 0.05). The surface area of villi increased in the MOS-supplemented group compared to the control group (P ≤ 0.05). There was a significant difference in V:C ratio between supplemented groups and control group (P ≤ 0.05). Based on these results, there is potential for CALSPORIN and IMW50 to reduce Salmonella shedding in feces, enhance ileal mucosal health, and improve growth performance of turkey poults.

Campylobacter jejuni Strains Associated with Wild Birds and Those Causing Human Disease in Six High-Use Recreational Waterways in New Zealand

Campylobacter jejuni, a leading cause of gastroenteritis worldwide, has been frequently isolated from recreational rivers and streams in New Zealand, yet the public health significance of this is unknown. This study uses molecular tools to improve our understanding of the epidemiology and sources of Campylobacter in recreational waterways, with a view to preventing human infection. Epidemiological and microbiological data were collected between 2005 and 2009 from six high-use recreational waterways in the Manawatu-Wanganui region of the North Island. Campylobacter spp. and C. jejuni were isolated from 33.2% and 20.4% of 509 samples, respectively. Isolation of Campylobacter was observed in both low and high river flows. After adjusting for the confounding effects of river flow, there was a significantly higher likelihood of isolating Campylobacter in the winter month of June compared to January. A high diversity of C. jejuni multilocus sequence types was seen, with the most commonly isolated being the water rail-associated ST-2381 (19/91 isolates [20.9%]), ST-1225 (8/91 isolates [8.8%]), and ST-45 (6/91 isolates [6.6%]). The ST-2381 was found in all rivers, while the most commonly isolated ST from human cases in New Zealand, the poultry-associated strain ST-474, was isolated only in one river. Although the majority of Campylobacter sequence types identified in river water were strains associated with wild birds that are rarely associated with human disease, poultry and ruminant-associated Campylobacter strains that are found in human infection were also identified and could present a public health risk.IMPORTANCE In 2016, there was a large-scale waterborne outbreak of campylobacteriosis in New Zealand, which was estimated to have affected over 5,000 people. This highlighted the need for a greater understanding of the sources of contamination of both surface and groundwater and risks associated with exposure to both drinking and recreational water. This study reports the prevalence and population structure of Campylobacter jejuni in six recreational waters of the Manawatu-Wanganui region of New Zealand and models the relationship between Campylobacter spp. and ruminant-associated Campylobacter and the parameters "sites," "months," and "river flow." Here, we demonstrate that both low and high river flows, month of the year, and recreational sites could influence the Campylobacter isolation from recreational waters. The presence of genotypes associated with human infection allowed us to describe potential risks associated with recreational waters.

Spatio-temporal analysis of differences in campylobacteriosis incidence between urban and rural areas in the Southern District Health Board, New Zealand

The objective of this paper is to investigate differences in campylobacteriosis incidence between urban and rural areas in the Southern District Health Board of New Zealand between 2000 and 2015. The data were analysed using a Bayesian change-point model to evaluate how campylobacteriosis incidence changed over time and to see whether the dynamics differed between rural and urban areas. A conditional auto regressive error term was introduced to account for any spatial effects. The results of our analysis showed that campylobacteriosis incidence increased between 2000 and 2005, decreased between 2006 and 2008 then stabilised from 2009 onward. In addition we found that the changes in incidence were greater in urban areas than in rural ones.

Epidemiology of Campylobacter Gastroenteritis in New Zealand Children and the Effect of The Campylobacter Strategy: A 20-year Observational Study

BACKGROUND

Campylobacter species are a common cause of gastroenteritis in New Zealand (NZ) as well as worldwide. This study aimed to describe epidemiologic trends in disease notifications and hospital admissions because of Campylobacter gastroenteritis in NZ children from 1997 to 2016.

METHODS

In this population-based descriptive study, age-specific and age-standardized notification and hospitalization rates were analyzed for Campylobacter infections in children <15 years of age. Variations in disease by time, sex, age, ethnicity and geography were described.

RESULTS

During the 20-year period considered, there were 39,970 notifications (59.1% male) and 1458 hospitalizations (61.8% male) because of Campylobacter gastroenteritis in NZ children. Before 2006, notification rates increased by 3.4% annually [95% confidence interval (CI): 0.7%-6.2%], with a peak of 340 notifications per 100,000 children in 2003. The average percentage change (APC) in hospitalizations was 7.4% (95% CI: 4.0%-10.9%) in the same period. From 2006 to 2008, notification and hospitalization rates fell by 25% and 30%, respectively. Since 2008, age-standardized incidence rates have been stable at 161 notifications (APC: -3.1; 95% CI: 0.82 to -6.9) and 6.73 hospitalizations (APC: 2.2; 95% CI: -2.0 to 6.5) per 100,000 children per year. Notification rates were highest in children 1-4 years of age. Hospitalizations rates were highest in children <1 year of age.

CONCLUSIONS

NZ has previously had high rates of Campylobacter gastroenteritis in children. Implementation of a national strategy to reduce foodborne Campylobacter infection appears to have contributed to an observed reduction in rates between 2006 and 2008. The burden of Campylobacter disease is highest in the community health setting, with only a small proportion of cases needing hospitalization.

Multilocus sequence typing (MLST), porA and flaA typing of Campylobacter jejuni isolated from cats attending a veterinary clinic

OBJECTIVE

Campylobacter is a major cause of gastroenteritis in humans and pet ownership is a risk factor for infection. To study the occurrence, species distribution and sequence-based types of Campylobacter spp. in pet cats, 82 faecal samples were collected from cats in New Zealand. The PCR positive samples of Campylobacter jejuni were characterized by multilocus sequence typing (MLST), major outer membrane protein gene (porA) and flagellin A gene (flaA) sequence typing.

RESULTS

Seven faecal samples were tested positive for Campylobacter spp. (9%, or 4-17% at 95% confidence interval), of which six were identified as C. jejuni, and one was C. upsaliensis. The six C. jejuni isolates were characterised by MLST; four belonged to ST-45 clonal complex and two of the isolates could not be typed. Two flaA-SVR types were identified: three samples were flaA-SVR type 8 and one belonged to 239. By combining all data, three isolates were indistinguishable with allelic combinations of ST-45, flaA-SVR 8, porA 44, although no epidemiological connection between these isolates could be established. To conclude, healthy cats can carry C. jejuni, whose detected genetic diversity is limited. The isolated sequence type ST-45 is frequently reported in human illnesses.

Exposure to whole chicken carcasses may present a greater risk of campylobacteriosis compared to exposure to chicken drumsticks

In New Zealand, the major risk factor for campylobacteriosis has been identified as poultry consumption. New Zealanders consume different types of chicken meat which undergo different processing before entering the retail chain. The manipulations and jointing of chicken carcasses into pieces and the subsequent processing and packaging have the potential to cross-contaminate and reshuffle bacterial pathogens among the different products sold. The aim of this study was to analyse: (a) the differences in the viable count and population genetic structure between Campylobacter isolated from chicken drumsticks and whole carcass meat for retail sale over a 1-year period; and (b) the genetic relatedness of human and chicken isolates collected concurrently. Enumeration of Campylobacter was performed using a spiral plater combined with manual spread plating. Campylobacter isolates were identified by polymerase chain reaction and typed by multilocus sequence typing (MLST). C. jejuni was the dominant species among both whole carcasses (63.5%) and drumsticks samples (73.8%), followed by C. coli (27% and 23.1%, respectively). After sample weight adjustment, whole carcasses showed significantly higher Campylobacter counts than drumsticks, with a significant difference in the counts between the commercial suppliers in both types of retail meat. MLST revealed 28 different sequence types among the two types of meat. Using permutational multivariate analysis of variance, statistically significant differences in the population genetic structures were observed between different suppliers but were not observed between the two types of chicken retail meat. In conclusion, we found differences in Campylobacter viable counts, suggesting consumption of whole carcasses may determine an exposure to a higher number of Campylobacter bacteria than consumption of chicken drumsticks. The Campylobacter population genetic structure did not differ between the two types of chicken retail meat. Therefore, source attribution studies based on MLST are unlikely to be biased by the selection of these types of retail meat during sampling.

Knowledge gaps in control of Campylobacter for prevention of campylobacteriosis

Campylobacteriosis is an important, worldwide public health problem with numerous socio-economic impacts. Since 2015, approximately 230,000 cases have been reported annually in Europe. In the United States, Australia and New Zealand, campylobacteriosis is the most commonly reported disease. Poultry and poultry products are considered important sources of human infections. Poultry meat can become contaminated with Campylobacter during slaughter if live chickens are intestinal carriers. Campylobacter spp. can be transferred from animals to humans through consumption and handling of contaminated food products, with fresh chicken meat being the most commonly implicated food type. Regarding food-borne disease, the most important Campylobacter species are Campylobacter jejuni and Campylobacter coli. In humans, clinical signs of campylobacteriosis include diarrhoea, abdominal pain, fever, headache, nausea and vomiting. Most cases of campylobacteriosis are sporadic and self-limiting, but there are post-infection complications, for example, Guillain-Barrés syndrome. This review summarizes an analysis undertaken by the DISCONTOOLS group of experts on campylobacteriosis. Gaps were identified in: (i) knowledge of true number of infected humans; (ii) mechanisms of pathogenicity to induce infection in humans; (iii) training to prevent transfer of Campylobacter from raw to ready-to-eat food; (iv) development of effective vaccines; (v) understanding transmission routes to broiler flocks; (vi) knowledge of bacteriocins, bacteriophages and antimicrobial peptides as preventive therapies; (vii) ration formulation as an effective preventive measure at a farm level; (viii) development of kits for rapid detection and quantification of Campylobacter in animals and food products; and (ix) development of more effective antimicrobials for treatment of humans infected with Campylobacter. Some of these gaps are relevant worldwide, whereas others are more related to problems encountered with Campylobacter in industrialized countries.

Characterisation by multilocus sequence and porA and flaA typing of Campylobacter jejuni isolated from samples of dog faeces collected in one city in New Zealand

AIMS

To investigate the prevalence of Campylobacter spp. and C. jejuni in dog faecal material collected from dog walkways in the city of Palmerston North, New Zealand, and to characterise the C. jejuni isolates by multilocus sequence typing (MLST) and porA and flaA antigen gene typing.

METHODS

A total of 355 fresh samples of dogs faeces were collected from bins provided for the disposal of dog faeces in 10 walkways in Palmerston North, New Zealand, between August 2008-July 2009. Presumptive Campylobacter colonies, cultured on modified charcoal cefoperazone deoxycholate plates, were screened for genus Campylobacter and C. jejuni by PCR. The C. jejuni isolates were subsequently characterised by MLST and porA and flaA typing, and C. jejuni sequence types (ST) were assigned.

RESULTS

Of the 355 samples collected, 72 (20 (95% CI=16-25)%) were positive for Campylobacter spp. and 22 (6 (95% CI=4-9)%) were positive for C. jejuni. Of the 22 C. jejuni isolates, 19 were fully typed by MLST. Ten isolates were assigned to the clonal complex ST-45 and three to ST-52. The allelic combinations of ST-45/flaA 21/porA 44 (n=3), ST-45/flaA 22/porA 53 (n=3) and ST-52/ flaA 57/porA 905 (n=3) were most frequent.

CONCLUSIONS

The successful isolation of C. jejuni from canine faecal samples collected from faecal bins provides evidence that Campylobacter spp. may survive outside the host for at least several hours despite requiring fastidious growth conditions in culture. The results show that dogs carry C. jejuni genotypes (ST-45, ST-50, ST-52 and ST-696) that have been reported in human clinical cases.

CLINICAL RELEVANCE

Although these results do not provide any evidence either for the direction of infection or for dogs being a potential risk factor for human campylobacteriosis, dog owners are advised to practice good hygiene with respect to their pets to reduce potential exposure to infection.

Cryptosporidiosis Risk in New Zealand Children Under 5 Years Old is Greatest in Areas with High Dairy Cattle Densities

The public health risks associated with dairy farming intensification are an emerging concern. We examine the association between dairy cattle density and cryptosporidiosis risk in children <5 years old in New Zealand from 1997 to 2008, a period of rapid intensification of the dairy industry. Multi-level Poisson regression was used to model reported cryptosporidiosis (N = 3869 cases) incidence in relation to dairy cattle densities across urban and rural areas separately, after controlling for microbiological quality of public drinking water supplies and neighbourhood socio-economic factors using the Census Area Unit of residence. Within urban areas, the risk of cryptosporidiosis in children less than 5 years old was significantly, positively associated with medium and high dairy cattle density IRR 1.3 (95% CI 1.2, 1.5) and 1.5 (95% CI 1.2, 1.9) respectively, when compared to areas with no dairy cattle. Within rural areas, the incidence risk of cryptosporidiosis in children less than 5 years old were significantly, positively associated with medium and high dairy cattle density: IRR 1.7 (95% CI 1.3, 2.3) and 2.0 (95% CI 1.5, 2.8) respectively, when compared to areas with no dairy cattle. These results have public health implications for children living on and in proximity to intensively stocked dairy cattle farms.

Filling gaps in notification data: a model-based approach applied to travel related campylobacteriosis cases in New Zealand

Background

Data containing notified cases of disease are often compromised by incomplete or partial information related to individual cases. In an effort to enhance the value of information from enteric disease notifications in New Zealand, this study explored the use of Bayesian and Multiple Imputation (MI) models to fill risk factor data gaps. As a test case, overseas travel as a risk factor for infection with campylobacteriosis has been examined.

Methods

Two methods, namely Bayesian Specification (BAS) and Multiple Imputation (MI), were compared regarding predictive performance for various levels of artificially induced missingness of overseas travel status in campylobacteriosis notification data. Predictive performance of the models was assessed through the Brier Score, the Area Under the ROC Curve and the Percent Bias of regression coefficients. Finally, the best model was selected and applied to predict missing overseas travel status of campylobacteriosis notifications.

Results

While no difference was observed in the predictive performance of the BAS and MI methods at a lower rate of missingness (<10 %), but the BAS approach performed better than MI at a higher rate of missingness (50 %, 65 %, 80 %). The estimated proportion (95 % Credibility Intervals) of travel related cases was greatest in highly urban District Health Boards (DHBs) in Counties Manukau, Auckland and Waitemata, at 0.37 (0.12, 0.57), 0.33 (0.13, 0.55) and 0.28 (0.10, 0.49), whereas the lowest proportion was estimated for more rural West Coast, Northland and Tairawhiti DHBs at 0.02 (0.01, 0.05), 0.03 (0.01, 0.08) and 0.04 (0.01, 0.06), respectively. The national rate of travel related campylobacteriosis cases was estimated at 0.16 (0.02, 0.48).

Conclusion

The use of BAS offers a flexible approach to data augmentation particularly when the missing rate is very high and when the Missing At Random (MAR) assumption holds. High rates of travel associated cases in urban regions of New Zealand predicted by this approach are plausible given the high rate of travel in these regions, including destinations with higher risk of infection. The added advantage of using a Bayesian approach is that the model’s prediction can be improved whenever new information becomes available.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1784-8) contains supplementary material, which is available to authorized users.

Cryptosporidiosis: A Disease of Tropical and Remote Areas in Australia

Cryptosporidiosis causes gastroenteritis and is transmitted to humans via contaminated water and food, and contact with infected animals and people. We analyse long-term cryptosporidiosis patterns across Australia (2001–2012) and review published Australian studies and jurisdictional health bulletins to identify high risk populations and potential risk factors for disease. Using national data on reported cryptosporidiosis, the average annual rate of reported illness was 12.8 cases per 100 000 population, with cycles of high and low reporting years. Reports of illness peak in summer, similar to other infectious gastrointestinal diseases. States with high livestock densities like New South Wales and Queensland also record a spring peak in illnesses. Children aged less than four years have the highest rates of disease, along with adult females. Rates of reported cryptosporidiosis are highest in the warmer, remote regions and in Aboriginal and Torres Strait Islander populations. Our review of 34 published studies and seven health department reports on cryptosporidiosis in Australia highlights a lack of long term, non-outbreak studies in these regions and populations, with an emphasis on outbreaks and risk factors in urban areas. The high disease rates in remote, tropical and subtropical areas and in Aboriginal and Torres Strait Islander populations underscore the need to develop interventions that target the sources of infection, seasonal exposures and risk factors for cryptosporidiosis in these settings. Spatial epidemiology can provide an evidence base to identify priorities for intervention to prevent and control cryptosporidiosis in high risk populations.

The parasite Cryptosporidium is a common cause of gastroenteritis worldwide. Ineffectively focused interventions are partly why the disease remains a challenge to control. In this study, we describe the geographical, seasonal and demographic characteristics of reported cryptosporidiosis in Australia from 2001–2012. We combine this analysis of illnesses with evidence published in peer review articles and state health bulletins to identify high disease risk areas and populations. We find that rates of reported cryptosporidiosis are highest in warm, remote areas and in Aboriginal and Torres Strait Islander populations’ dominated regions. Our review of the published literature and health reports highlights a focus on short term outbreaks in metropolitan areas. This negligible overlap between areas with high disease rates and areas of public health focus is of concern. Public health interventions and promotion programs to prevent and control diarrhoea need to focus on remote and Indigenous dominated Australia to reduce the currently high rates in these regions and populations.

Virulence characterization of Campylobacter jejuni isolated from resident wild birds in Tokachi area, Japan

The prevalence of Campylobacter jejuni in wild birds is a potential hazard for human and animal health. The aim of this study was to establish the prevalence of C. jejuni in wild birds in Tokachi area, Hokkaido, Japan and investigate their virulence in vitro. In total, 173 cloacal swabs from individual wild birds were collected for the detection of Campylobacter spp. Thirty four samples (19.7%) were positive for Campylobacter of which 94.1% (32/34 samples) were C. jejuni. Additionally, one C. coli and one C. fetus were isolated. Seven C. jejuni isolates (one from crows and the other from pigeons) had important virulence genes including all three CDT genes (cdtA, cdtB and cdtC) and flaA, flaB, ciaB and cadF, and the other isolates were lacking cdtA gene. Further studies on in vitro virulence-associated phenotypes, such as motility assay on soft agar and invasion assay in Caco-2 cells, were performed. The wild bird C. jejuni isolates adhered and invaded human cells. Although the numbers of viable intracellular bacteria of wild bird isolates were lower than a type strain NCTC11168, they persisted at 48-hr and underwent replication in host cells.

Heterogeneity in hotspots: spatio-temporal patterns in neglected parasitic diseases

Cryptosporidiosis and giardiasis have been recognized by the WHO as 'Neglected Diseases'. Minimal attention has been paid to the spatial and temporal distribution of disease incidence patterns. Using disease notification data, we detected spatio-temporal clusters of cryptosporidiosis and giardiasis across three time periods: (i) 1997-2000, (ii) 2001-2004, (iii) 2005-2008. There was substantial variation in the geographical location and timing of recurrent cryptosporidiosis and giardiasis clusters. Statistically significant (P < 0·05) giardiasis clusters tended to occur in predominantly urban areas with little apparent seasonal influence, while statistically significant cryptosporidiosis clusters were detected in spring, in areas with high livestock land use. The location and timing of cryptosporidiosis clusters suggest an influence of livestock production practices, while urban exposures and host behaviour are likely to influence giardiasis clusters. This approach provides a resource-efficient method for public health authorities to prioritize future research needs and areas for intervention.

Prevalence, virulence, and antimicrobial resistance of Campylobacter jejuni and Campylobacter coli in white stork Ciconia ciconia in Poland

The aim of this study was to investigate the role of white stork Ciconia ciconia as a potential reservoir of Campylobacter spp. Antimicrobial resistance and the presence of putative virulence genes of the isolates were also examined. A total of 398 white stork chicks sampled in Western Poland in habitats with high density of breeding were examined. Rectal swabs were collected during breeding season 2009-2012 from storks developing in a relatively pure environment (Odra meadows), in polluted areas (a copper mining-smelting complex), and in suburbs. Of the anal swabs collected, 7.6% were positive for Campylobacter among chicks (5.3% samples positive for C. jejuni and 2.3% samples positive for C. coli). Samples from polluted areas had the highest prevalence of Campylobacter (12.2%). The prevalence of resistance among C. jejuni and C. coli isolates from young storks was as follows: to ciprofloxacin (52.4%, 44.4%), and to tetracycline (19%, 77.8%). All of the analyzed isolates were susceptible to macrolides. The resistance to both classes of antibiotics was found in the 23.3% of Campylobacter spp. All Campylobacter spp. isolates had cadF gene and flaA gene responsible for adherence and motility. CdtB gene associated with toxin production was present in 88.9% of C. coli isolates and 57.1% of C. jejuni isolates. The iam marker was found more often in C. coli strains (55.6%) compared to C. jejuni isolates (42.9%). Our results confirm the prevalence of Campylobacter spp. in the white stork in natural conditions and, because it lives in open farmlands with access to marshy wetlands, the environmental sources such as water reservoirs and soil-water can be contaminated from white stork feces and the pathogens can be widely disseminated. We can thus conclude that Campylobacter spp. may easily be transmitted to waterfowl, other birds, and humans via its environmental sources and/or by immediate contact.

Spatio-temporal modelling of disease incidence with missing covariate values

The search for an association between disease incidence and possible risk factors using surveillance data needs to account for possible spatial and temporal correlations in underlying risk. This can be especially difficult if there are missing values for some important covariates. We present a case study to show how this problem can be overcome in a Bayesian analysis framework by adding to the usual spatio-temporal model a component for modelling the missing data.

Burden of laboratory-confirmed Campylobacter infections in Guatemala 2008-2012: results from a facility-based surveillance system

INTRODUCTION

Campylobacteriosis is one of the leading causes of gastroenteritis worldwide. This study describes the epidemiology of laboratory-confirmed Campylobacter diarrheal infections in two facility-based surveillance sites in Guatemala.

METHODS

Clinical, epidemiologic, and laboratory data were collected on patients presenting with acute diarrhea from select healthcare facilities in the departments of Santa Rosa and Quetzaltenango, Guatemala, from January 2008 through August 2012. Stool specimens were cultured for Campylobacter and antimicrobial susceptibility testing was performed on a subset of isolates. Multidrug resistance (MDR) was defined as resistance to ≥3 antimicrobial classes.

RESULTS

Campylobacter was isolated from 306 (6.0%) of 5137 stool specimens collected. For children <5 years of age, annual incidence was as high as 1288.8 per 100,000 children in Santa Rosa and 185.5 per 100,000 children in Quetzaltenango. Among 224 ambulatory care patients with Campylobacter, 169 (75.5%) received metronidazole or trimethoprim-sulfamethoxazole, and 152 (66.7%) received or were prescribed oral rehydration therapy. Antimicrobial susceptibilities were tested in 96 isolates; 57 (59.4%) were resistant to ciprofloxacin and 12 (12.5%) were MDR.

CONCLUSION

Campylobacter was a major cause of diarrhea in children in two departments in Guatemala; antimicrobial resistance was high, and treatment regimens in the ambulatory setting which included metronidazole and trimethoprim-sulfamethoxazole and lacked oral rehydration were sub-optimal.

Population-based incidence and comparative demographics of community-associated and healthcare-associated Escherichia coli bloodstream infection in Auckland, New Zealand, 2005-2011

Background

Escherichia coli is a major human pathogen, both in community and healthcare settings. To date however, relatively few studies have defined the population burden of E. coli bloodstream infections. Such information is important in informing strategies around treatment and prevention of these serious infections. Against this background, we performed a retrospective, population-based observational study of all cases of E. coli bacteremia in patients presenting to our hospital between January 2005 and December 2011.

Methods

Auckland District Health Board is a tertiary-level, university-affiliated institution serving a population of approximately 500,000, within a larger metropolitan population of 1.4 million. We identified all patients with an episode of bloodstream infection due to E. coli over the study period. A unique episode was defined as the first positive E. coli blood culture taken from the same patient within a thirty-day period. Standard definitions were used to classify episodes into community- or healthcare-associated E. coli bacteremia. Demographic information was obtained for all patients, including: age; gender; ethnicity; length of stay (days); requirement for intensive care admission and all-cause, in-patient mortality.

Results

A total of 1507 patients had a unique episode of E. coli bacteremia over the study period. The overall average annual incidence of E. coli bacteremia was 52 per 100,000 population, and was highest in the under one year and over 65-year age groups. When stratified by ethnicity, rates were highest in Pacific Peoples and Māori (83 and 62 per 100,000 population respectively). The incidence of community-onset E. coli bacteremia increased significantly over the study period. The overall in-hospital mortality rate was 9% (135/1507), and was significantly higher in patients who had a hospital-onset E. coli bacteremia.

Conclusions

Our work provides valuable baseline data on the incidence of E. coli bacteremia in our locale. The incidence was higher that that described from other developed countries, with significant demographic variation, most notably in ethnic-specific incidence rates. Future work should assess the possible reasons for this disparity.

Campylobacter jejuni colonization and population structure in urban populations of ducks and starlings in New Zealand

A repeated cross-sectional study was conducted to determine the prevalence of Campylobacter spp. and the population structure of C. jejuni in European starlings and ducks cohabiting multiple public access sites in an urban area of New Zealand. The country's geographical isolation and relatively recent history of introduction of wild bird species, including the European starling and mallard duck, create an ideal setting to explore the impact of geographical separation on the population biology of C. jejuni, as well as potential public health implications. A total of 716 starling and 720 duck fecal samples were collected and screened for C. jejuni over a 12 month period. This study combined molecular genotyping, population genetics and epidemiological modeling and revealed: (i) higher Campylobacter spp. isolation in starlings (46%) compared with ducks (30%), but similar isolation of C. jejuni in ducks (23%) and starlings (21%), (ii) significant associations between the isolation of Campylobacter spp. and host species, sampling location and time of year using logistic regression, (iii) evidence of population differentiation, as indicated by F_ST, and host-genotype association with clonal complexes CC ST-177 and CC ST-682 associated with starlings, and clonal complexes CC ST-1034, CC ST-692, and CC ST-1332 associated with ducks, and (iv) greater genetic diversity and genotype richness in ducks compared with starlings. These findings provide evidence that host-associated genotypes, such as the starling-associated ST-177 and ST-682, represent lineages that were introduced with the host species in the 19th century. The isolation of sequence types associated with human disease in New Zealand indicate that wild ducks and starlings need to be considered as a potential public health risk, particularly in urban areas.

We applied molecular epidemiology and population genetics to obtain insights in to the population structure, host-species relationships, gene flow and evolution of Campylobacter jejuni in urban ducks and starlings.

Comparison of time series models for predicting campylobacteriosis risk in New Zealand

Predicting campylobacteriosis cases is a matter of considerable concern in New Zealand, after the number of the notified cases was the highest among the developed countries in 2006. Thus, there is a need to develop a model or a tool to predict accurately the number of campylobacteriosis cases as the Microbial Risk Assessment Model used to predict the number of campylobacteriosis cases failed to predict accurately the number of actual cases. We explore the appropriateness of classical time series modelling approaches for predicting campylobacteriosis. Finding the most appropriate time series model for New Zealand data has additional practical considerations given a possible structural change, that is, a specific and sudden change in response to the implemented interventions. A univariate methodological approach was used to predict monthly disease cases using New Zealand surveillance data of campylobacteriosis incidence from 1998 to 2009. The data from the years 1998 to 2008 were used to model the time series with the year 2009 held out of the data set for model validation. The best two models were then fitted to the full 1998-2009 data and used to predict for each month of 2010. The Holt-Winters (multiplicative) and ARIMA (additive) intervention models were considered the best models for predicting campylobacteriosis in New Zealand. It was noticed that the prediction by an additive ARIMA with intervention was slightly better than the prediction by a Holt-Winter multiplicative method for the annual total in year 2010, the former predicting only 23 cases less than the actual reported cases. It is confirmed that classical time series techniques such as ARIMA with intervention and Holt-Winters can provide a good prediction performance for campylobacteriosis risk in New Zealand. The results reported by this study are useful to the New Zealand Health and Safety Authority's efforts in addressing the problem of the campylobacteriosis epidemic.

Socioeconomic determinants of geographic disparities in campylobacteriosis risk: a comparison of global and local modeling approaches

Background

Socioeconomic factors play a complex role in determining the risk of campylobacteriosis. Understanding the spatial interplay between these factors and disease risk can guide disease control programs. Historically, Poisson and negative binomial models have been used to investigate determinants of geographic disparities in risk. Spatial regression models, which allow modeling of spatial effects, have been used to improve these modeling efforts. Geographically weighted regression (GWR) takes this a step further by estimating local regression coefficients, thereby allowing estimations of associations that vary in space. These recent approaches increase our understanding of how geography influences the associations between determinants and disease. Therefore the objectives of this study were to: (i) identify socioeconomic determinants of the geographic disparities of campylobacteriosis risk (ii) investigate if regression coefficients for the associations between socioeconomic factors and campylobacteriosis risk demonstrate spatial variability and (iii) compare the performance of four modeling approaches: negative binomial, spatial lag, global and local Poisson GWR.

Methods

Negative binomial, spatial lag, global and local Poisson GWR modeling techniques were used to investigate associations between socioeconomic factors and geographic disparities in campylobacteriosis risk. The best fitting models were identified and compared.

Results

Two competing four variable models (Models 1 & 2) were identified. Significant variables included race, unemployment rate, education attainment, urbanicity, and divorce rate. Local Poisson GWR had the best fit and showed evidence of spatially varying regression coefficients.

Conclusions

The international significance of this work is that it highlights the inadequacy of global regression strategies that estimate one parameter per independent variable, and therefore mask the true relationships between dependent and independent variables. Since local GWR estimate a regression coefficient for each location, it reveals the geographic differences in the associations. This implies that a factor may be an important determinant in some locations and not others. Incorporating this into health planning ensures that a needs-based, rather than a “one-size-fits-all”, approach is used. Thus, adding local GWR to the epidemiologists’ toolbox would allow them to assess how the impacts of different determinants vary by geography. This knowledge is critical for resource allocation in disease control programs.

Declining Guillain-Barré syndrome after campylobacteriosis control, New Zealand, 1988-2010

Food safety measures that lower incidence of campylobacteriosis might also prevent Guillain-Barré syndrome.

Increasing incidence of serious infectious diseases and inequalities in New Zealand: a national epidemiological study

BACKGROUND

Although the burden of infectious diseases seems to be decreasing in developed countries, few national studies have measured the total incidence of these diseases. We aimed to develop and apply a robust systematic method for monitoring the epidemiology of serious infectious diseases.

METHODS

We did a national epidemiological study with all hospital admissions for infectious and non-infectious diseases in New Zealand from 1989 to 2008, to investigate trends in incidence and distribution by ethnic group and socioeconomic status. We extended a recoding system based on the ninth revision of international classification of diseases (ICD-9) to the tenth revision (ICD-10), and applied this to data for hospital admissions from the New Zealand Ministry of Health, National Minimum Dataset. We filtered results to account for changes in health-care practices over time. Acute overnight admissions were the events of interest.

FINDINGS

Infectious diseases made the largest contribution to hospital admissions of any cause. Their contribution increased from 20·5% of acute admissions in 1989-93, to 26·6% in 2004-08. We noted clear ethnic and social inequalities in infectious disease risk. In 2004-08, the age-standardised rate ratio was 2·15 (95% CI 2·14-2·16) for Māori (indigenous New Zealanders) and 2·35 (2·34-2·37) for Pacific peoples compared with the European and other group. The ratio was 2·81 (2·80-2·83) for the most socioeconomically deprived quintile compared with the least deprived quintile. These inequalities have increased substantially in the past 20 years, particularly for Māori and Pacific peoples in the most deprived quintile.

INTERPRETATION

These findings support the need for stronger prevention efforts for infectious diseases, and reinforce the need to reduce ethnic and social inequalities and to address disparities in broad social determinants such as income levels, housing conditions, and access to health services. Our method could be adapted for infectious disease surveillance in other countries.

FUNDING

New Zealand Ministry of Health, New Zealand Health Research Council.

Laboratory-based surveillance of Campylobacter and Salmonella infection and the importance of denominator data

Laboratory data are the cornerstone in surveillance of infectious disease. We investigated whether changes in reported incidence of Campylobacter and Salmonella infection might be explained by changes in stool sampling rates. Data were extracted from a national database on 585 843 patient stool samples tested by microbiology laboratories in Wales between 1998 and 2008. Salmonella incidence fell from 43 to 19 episodes/100 000 population but Campylobacter incidence after declining from 111/100 000 in 1998 to 84/100 000 in 2003 rose to 119/100 000 in 2008. The proportion of the population sampled rose from 2·0% in 1998 to 2·8% in 2008, mostly due to increases in samples from hospital patients and older adults. The proportion of positive samples declined for both Salmonella and Campylobacter from 3·1% to 1·1% and from 8·9% to 7·5%, respectively. The decline in Salmonella incidence is so substantial that it is not masked even by increased stool sampling, but the recent rise in Campylobacter incidence may be a surveillance artefact largely due to the increase in stool sampling in older people.

The epidemiology of human salmonellosis in New Zealand, 1997–2008

This study describes the epidemiology of human salmonellosis in New Zealand using notified, hospitalized and fatal cases over a 12-year period (1997–2008). The average annual incidence for notifications was 42·8/100 000 population and 3·6/100 000 population for hospitalizations. Incidence was about twice as high in summer as in winter. Rural areas had higher rates than urban areas (rate ratio 1·23, 95% confidence interval 1·22–1·24 for notifications) and a distinct spring peak. Incidence was highest in the 0–4 years age group (154·2 notifications/100 000 and 11·3 hospitalizations/100 000). Hospitalizations showed higher rates for Māori and Pacific Island populations compared to Europeans, and those living in more deprived areas, whereas notifications showed the reverse, implying that notifications are influenced by health-seeking behaviours.SalmonellaTyphimurium was the dominant serotype followed byS. Enteritidis. For a developed country, salmonellosis rates in New Zealand have remained consistently high suggesting more work is needed to investigate, control and prevent this disease.

Whole-genome comparison of two Campylobacter jejuni isolates of the same sequence type reveals multiple loci of different ancestral lineage

Campylobacter jejuni ST-474 is the most important human enteric pathogen in New Zealand, and yet this genotype is rarely found elsewhere in the world. Insight into the evolution of this organism was gained by a whole genome comparison of two ST-474, flaA SVR-14 isolates and other available C. jejuni isolates and genomes. The two isolates were collected from different sources, human (H22082) and retail poultry (P110b), at the same time and from the same geographical location. Solexa sequencing of each isolate resulted in 1.659 Mb (H22082) and 1.656 Mb (P110b) of assembled sequences within 28 (H22082) and 29 (P110b) contigs. We analysed 1502 genes for which we had sequences within both ST-474 isolates and within at least one of 11 C. jejuni reference genomes. Although 94.5% of genes were identical between the two ST-474 isolates, we identified 83 genes that differed by at least one nucleotide, including 55 genes with non-synonymous substitutions. These covered 101 kb and contained 672 point differences. We inferred that 22 (3.3%) of these differences were due to mutation and 650 (96.7%) were imported via recombination. Our analysis estimated 38 recombinant breakpoints within these 83 genes, which correspond to recombination events affecting at least 19 loci regions and gives a tract length estimate of 2 kb. This includes a 12 kb region displaying non-homologous recombination in one of the ST-474 genomes, with the insertion of two genes, including ykgC, a putative oxidoreductase, and a conserved hypothetical protein of unknown function. Furthermore, our analysis indicates that the source of this recombined DNA is more likely to have come from C. jejuni strains that are more closely related to ST-474. This suggests that the rates of recombination and mutation are similar in order of magnitude, but that recombination has been much more important for generating divergence between the two ST-474 isolates.

Marked campylobacteriosis decline after interventions aimed at poultry, New Zealand

Beginning in the 1980s, New Zealand experienced rising annual rates of campylobacteriosis that peaked in 2006. We analyzed notification, hospitalization, and other data to explore the 2007-2008 drop in campylobacteriosis incidence. Source attribution techniques based on genotyping of Campylobacter jejuni isolates from patients and environmental sources were also used to examine the decline. In 2008, the annual campylobacteriosis notification rate was 161.5/100,000 population, representing a 54% decline compared with the average annual rate of 353.8/100,000 for 2002-2006. A similar decline was seen for hospitalizations. Source attribution findings demonstrated a 74% (95% credible interval 49%-94%) reduction in the number of cases attributed to poultry. These reductions coincided with the introduction of a range of voluntary and regulatory interventions to reduce Campylobacter spp. contamination of poultry. The apparent success of these interventions may inform approaches other countries could consider to help control foodborne campylobacteriosis.

The spatial and temporal determinants of campylobacteriosis notifications in New Zealand, 2001–2007

Despite recent improvements, New Zealand still has one of the highest per-capita incidence rates of campylobacteriosis in the world. To reduce the incidence, a thorough understanding of the epidemiology of infection is needed. This retrospective analysis of 36 000 notified human cases during a high-risk period between 2001 and 2007 explored the spatial and temporal determinants of Campylobacter notifications at a fine spatial scale in order to improve understanding of the complex epidemiology. Social deprivation was associated with a decreased risk of notification, whereas urban residence was associated with an increased risk. However, for young children rural residence was a risk factor. High dairy cattle density was associated with an increased risk of notification in two of the three regions investigated. Campylobacter notification patterns exhibit large temporal variations; however, few factors were associated with periods of increased risk, in particular temperature did not appear to drive the seasonality in campylobacteriosis.

Marked campylobacteriosis decline after interventions aimed at poultry, New Zealand

Beginning in the 1980s, New Zealand experienced rising annual rates of campylobacteriosis that peaked in 2006. We analyzed notification, hospitalization, and other data to explore the 2007-2008 drop in campylobacteriosis incidence. Source attribution techniques based on genotyping of Campylobacter jejuni isolates from patients and environmental sources were also used to examine the decline. In 2008, the annual campylobacteriosis notification rate was 161.5/100,000 population, representing a 54% decline compared with the average annual rate of 353.8/100,000 for 2002-2006. A similar decline was seen for hospitalizations. Source attribution findings demonstrated a 74% (95% credible interval 49%-94%) reduction in the number of cases attributed to poultry. These reductions coincided with the introduction of a range of voluntary and regulatory interventions to reduce Campylobacter spp. contamination of poultry. The apparent success of these interventions may inform approaches other countries could consider to help control foodborne campylobacteriosis.

Climate change and infectious diseases in New Zealand: a brief review and tentative research agenda

AIMS

To review the literature on infectious diseases and meteorological and climate change risk factors in the New Zealand context and to describe a tentative research agenda for future work.

METHODS

We performed literature searches in May 2010 using Medline and Google Scholar. We also searched five health-related government agencies in New Zealand for documentation on climate change and health.

RESULTS

The effect of climate variability and change on vector-borne disease has been considered in more detail than any other infectious disease topic (n=20+ journal articles and reports relating to New Zealand). Generally, concern has arisen around the risk of new mosquito incursions and increased risks of dengue and Ross River fevers in the long term. For enteric diseases, the picture from five New Zealand publications is somewhat mixed, although the data indicate that salmonellosis notifications increase with higher monthly temperatures. One interpretation of the New Zealand data is that communities without reticulated water supplies could be more vulnerable to the effects of climate change-mediated increases in protozoan diseases. This information informed a tentative research agenda to address research gaps. Priorities include the need for further work on a more integrated surveillance framework, vector-borne diseases, enteric diseases, skin infections, and then work on topics for which we found no published New Zealand work (such as influenza and leptospirosis). Finally, we found that health-related government agencies in New Zealand have relatively little 'climate change and health' information on their websites.

CONCLUSIONS

Although some informative work has been done to date, much scope remains for additional research and planning to facilitate prevention, mitigation, and adaptation responses in the New Zealand setting around climate change and infectious disease risks. The tentative research agenda produced could benefit from a wider critique, and government agencies in New Zealand could contribute to informed discussions by better documenting the current state of knowledge on their websites.

Enteric campylobacteria and RNA viruses associated with healthy and diarrheic humans in the Chinook health region of southwestern Alberta, Canada

The presence of Campylobacter species and enteric RNA viruses in stools from diarrheic (n = 442) and healthy (n = 58) humans living in southwestern Alberta was examined (May to October 2005). A large number of diarrheic individuals who were culture negative for C. jejuni (n = 54) or C. coli (n = 19) were PCR positive for these taxa. Overall detection rates for C. jejuni and C. coli in diarrheic stools were 29% and 5%, respectively. In contrast, 3% and 0% of stools from healthy humans were positive for these taxa, respectively. Infection with C. jejuni was endemic over the study period. However, there was no difference in infection rates between individuals living in urban or rural locations. Stools from a large number of diarrheic (74%) and healthy (88%) individuals were positive for Campylobacter DNA. The prevalence rates of C. concisus, C. curvus, C. fetus, C. gracilis, C. helveticus, C. hominis, C. hyointestinalis, C. mucosalis, C. showae, C. sputorum, and C. upsaliensis DNA were either not significantly different or were significantly lower in stools from diarrheic than from healthy individuals. No C. lanienae or C. lari DNA was detected. Stools from 4% and 0% of diarrheic and healthy humans, respectively, were positive for rotavirus, sapovirus, or norovirus (GI/GII). Our results showed a high prevalence of diarrheic individuals living in southwestern Alberta who were infected by C. jejuni and, to a lesser extent, by C. coli. However, other Campylobacter species, norovirus, rotavirus, sapovirus, and bovine enteric calicivirus were either inconsequential pathogens during the study period or are not pathogens at all.

Acute gastrointestinal illness in New Zealand: a community study

We report the results of the New Zealand Acute Gastrointestinal Illness (AGI) Community Study, a representative cross-sectional community telephone survey of 3655 participants conducted over a 12-month period. Respondents were asked questions about vomiting and diarrhoea in the previous 4 weeks. At least one episode of diarrhoea and/or vomiting was reported by 8·6% of respondents, an incidence of 1·11 episodes/person per year. Prevalence was highest in children aged <5 years and lowest in those aged >64 years. The mean duration of illness was 2·5 days and most common symptoms were diarrhoea (82·5%), stomach cramps (75·7%), nausea (56·9%) and vomiting (49·0%). Extrapolation of the adjusted estimates indicates there are about 4·66 million episodes of AGI per year in New Zealand, nearly 1 million visits to the general medical practitioner, in excess of 300,000 courses of antibiotics being dispensed and more than 4·5 million days of paid work lost due to AGI. This represents a significant burden of disease.

Molecular and spatial epidemiology of human campylobacteriosis: source association and genotype-related risk factors

The epidemiology of human campylobacteriosis is complex but in recent years understanding of this disease has advanced considerably. Despite being a major public health concern in many countries, the presence of multiple hosts, genotypes and transmission pathways has made it difficult to identify and quantify the determinants of human infection and disease. This has delayed the development of successful intervention programmes for this disease in many countries including New Zealand, a country with a comparatively high, yet until recently poorly understood, rate of notified disease. This study investigated the epidemiology of Campylobacter jejuni at the genotype-level over a 3-year period between 2005 and 2008 using multilocus sequence typing. By combining epidemiological surveillance and population genetics, a dominant, internationally rare strain of C. jejuni (ST474) was identified, and most human cases (65.7%) were found to be caused by only seven different genotypes. Source association of genotypes was used to identify risk factors at the genotype-level through multivariable logistic regression and a spatial model. Poultry-associated cases were more likely to be found in urban areas compared to rural areas. In particular young children in rural areas had a higher risk of infection with ruminant strains than their urban counterparts. These findings provide important information for the implementation of pathway-specific control strategies.

The spatial distribution of campylobacteriosis in New Zealand, 1997-2005

In New Zealand Campylobacter infection rates have increased steadily since 1980, reaching a peak in 2003 (396/100,000 population). Compared to other nations, disease rates are unfavourably high (e.g. Australia 117/100,000 population, UK 85/100,000 population, USA 13/100,000 population). This ecological study investigated spatial variations in Campylobacter infection rates across New Zealand's Territorial Local Authorities (TLAs, n=73) for the period 1997-2005. Applying multiple linear regression, we examined whether geographical factors such as socio-demographic characteristics, climate, land use, water and the food environment were associated with local differences in the occurrence of Campylobacter infection rates. The results suggested significant variations in campylobacteriosis across TLAs (average annual rates ranging from 97 to 526/100,000 population), with higher rates in the South Island. Disease rates were associated with lower socio-economic deprivation (P<0.01), the proportion of the population aged 25-44 years (P<0.01) and fresh food outlet density (P<0.76). The results underline the role of area-level characteristics in explaining the spatial distribution of campylobacteriosis in New Zealand. In particular, the findings draw attention to the relatively unexplored role of fresh food outlets as a potential risk factor for increased Campylobacter notifications.

Helicobacter species in the human colon

OBJECTIVE

To determine the prevalence, frequency and colonization patterns of Helicobacter species throughout the colon.

METHOD

Patients having initial colonoscopy for nonspecific gastrointestinal disturbance had colonic biopsies taken from up to four sites during colonoscopy and examined for evidence of the Helicobacteraceae family using a group-specific PCR. Serum was also collected and examined for IgG reactivity to Helicobacter pylori.

RESULTS

100 patients had colonoscopy of whom 35 were found to have DNA evidence of Helicobacter species throughout the colon, with 22 having H. pylori. Fifteen patients had a demonstrable serum IgG response to H. pylori that was not always associated with molecular evidence of H. pylori DNA in colon biopsies and vice versa. No specific association with colon disease was found in patients with H. pylori infection.

CONCLUSION

We found evidence of Helicobacter infection in a significant number of patients presenting for colonoscopy but no specific association between the presence of these bacteria and colon disease. Our finding of disparity between molecular and serological techniques to detect Helicobacter species suggests that future studies should not rely on serology alone to detect these bacteria in the human colon.

Higher rate of culture-confirmed Campylobacter infections in Australia than in the USA: is this due to differences in healthcare-seeking behaviour or stool culture frequency?

Laboratory-based surveillance by OzFoodNet in Australia and FoodNet in the USA indicated that the incidence of Campylobacter infections in 2001 in Australia was about nine times higher than in the USA. We assessed whether this disparity could be explained by differences in the frequency of stool culturing. Using data from population surveys of diarrhoea and symptom profiles for Campylobacter from case-control studies, indices of healthcare behaviour taking into account the severity of Campylobacter infections were calculated. These suggest that culture-confirmed Campylobacter infections underestimate the incidence of community cases by similar ratios in the two countries. The incidence of Campylobacter infections in Australia was about 12 times higher than in the USA after consideration of healthcare system differences.