Shifts in the Molecular Epidemiology of Campylobacter jejuni Infections in a Sentinel Region of New Zealand following Implementation of Food Safety Interventions by the Poultry Industry.

In 2006, New Zealand had the highest notification rate of campylobacteriosis in the world, and poultry was considered the leading source of campylobacteriosis. Implementation of food safety interventions by the poultry industry led to a decrease in the campylobacteriosis notification rate. The aim is to examine the impact of targeted food safety interventions implemented by the New Zealand poultry industry on the source attribution of Campylobacter jejuni infections in a sentinel region. Campylobacter jejuni isolates collected from the Manawatu region of New Zealand between 2005 and 2007 ("before intervention") and 2008 and 2015 ("after intervention") from human clinical cases, chicken meat, ruminant feces, environmental water, and wild bird sources were subtyped by multilocus sequence typing. Viable counts of Campylobacter spp. from carcasses were analyzed using a zero-inflated Poisson regression model. In the period before intervention, sequence type 474 (ST-474) was the most common sequence type (ST) recovered from human cases, accounting for 28.2% of the isolates. After intervention, the proportion of human cases positive for ST-474 reduced to 9.3%. Modeling indicated that chicken meat, primarily from one supplier, was the main source of C. jejuni infection in the Manawatu region before intervention. However, after intervention poultry collectively had a similar attribution to ruminants, but more human cases were attributed to ruminants than any single chicken supplier. Viable counts on carcasses were lower in all poultry suppliers after intervention. This study provides evidence of changes in the source attribution of campylobacteriosis following targeted food safety interventions in one sector of the food supply chain.IMPORTANCE This study provides a unique insight into the effects of food safety interventions implemented in one sector of the food industry on the transmission routes of a major foodborne agent. Following the implementation of food safety interventions by the poultry industry, shifts in the molecular epidemiology of Campylobacter jejuni infections in a sentinel region of New Zealand were observed. Targeted interventions to reduce disease incidence are effective but require continued surveillance and analysis to indicate where further interventions may be beneficial.

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.

Molecular Epidemiology of Campylobacter coli Strains Isolated from Different Sources in New Zealand between 2005 and 2014.

UNLABELLED: Campylobacteriosis is one of the most important foodborne diseases worldwide and a significant health burden in New Zealand. Campylobacter jejuni is the predominant species worldwide, accounting for approximately 90% of human cases, followed by Campylobacter coli Most studies in New Zealand have focused on C. jejuni; hence, the impact of C. coli strains on human health is not well understood. The aim of this study was to genotype C. coli isolates collected in the Manawatu region of New Zealand from clinical cases, fresh poultry meat, ruminant feces, and environmental water sources, between 2005 and 2014, to study their population structure and estimate the contribution of each source to the burden of human disease. Campylobacter isolates were identified by PCR and typed by multilocus sequence typing. C. coli accounted for 2.9% (n = 47/1,601) of Campylobacter isolates from human clinical cases, 9.6% (n = 108/1,123) from poultry, 13.4% (n = 49/364) from ruminants, and 6.4% (n = 11/171) from water. Molecular subtyping revealed 27 different sequence types (STs), of which 18 belonged to clonal complex ST-828. ST-1581 was the most prevalent C. coli sequence type isolated from both human cases (n = 12/47) and poultry (n = 44/110). When classified using cladistics, all sequence types belonged to clade 1 except ST-7774, which belonged to clade 2. ST-854, ST-1590, and ST-4009 were isolated only from human cases and fresh poultry, while ST-3232 was isolated only from human cases and ruminant sources. Modeling indicated ruminants and poultry as the main sources of C. coli human infection. IMPORTANCE: We performed a molecular epidemiological study of Campylobacter coli infection in New Zealand, one of few such studies globally. This study analyzed the population genetic structure of the bacterium and included a probabilistic source attribution model covering different animal and water sources. The results are discussed in a global context.

An exploratory qualitative enquiry into workers' experiences of leptospirosis and post-leptospirosis in Aotearoa New Zealand.

AIMS: This pilot study describes the experiences of six people who reported post-leptospirosis symptoms. Our aim was to perform an exploratory qualitative study to document participants' experiences and to identify themes to gain understanding of the impact and burden experienced. METHODS: Participants self-recruited, meaning they had directly contacted the first author prior to the study commencing and had offered to tell their stories. Face-to-face semi-structured interviews were conducted in January 2016 and summative content analysis was used to distil themes. RESULTS: The participants were male, had been employed in livestock slaughter plants (n=2) or farming (n=4) when they first contracted leptospirosis and claimed they had been suffering from post-leptospirosis symptoms for 1-35 years. Symptoms included exhaustion, brain fog and mood swings, and participants' lifestyles and relationships were severely affected. Participants and their partners reported poor awareness and knowledge of leptospirosis when they sought help, and that employers and the Accident Compensation Corporation (ACC) were dismissive of post-leptospirosis symptoms. Participants also reported some positive experiences and had advice to share. CONCLUSION: Leptospirosis may have severe long-term consequences for patients, their families and their communities. We recommend that the aetiology, pathogenesis and burden of the persistence of leptospirosis symptoms become topics for future research.

"We don't really do doctors." messages from people diagnosed with occupational leptospirosis for medical professionals on infection, hospitalisation, and long-term effects.

Leptospirosis is largely an occupational disease for people working with livestock in Aotearoa New Zealand. Introduction of livestock vaccination and use of personal protective equipment has been associated with a reduction in the incidence. However, the incidence of occupational leptospirosis remains high, with significant burdens for affected families and healthcare system. For this article, a subset of thirteen participants from a nationwide leptospirosis case-control study (2019-2021) who were diagnosed with leptospirosis and worked with livestock at the time of illness were invited and agreed to a semi-structured interview. Interviewees reflected on their experiences as messages for medical professionals. The analysis of transcripts reveals widely shared experiences with infection, hospitalisation, and treatment, as well as long-term effects and recovery. Conclusions for medical professionals include that ill workers continue to have their diagnosis of leptospirosis delayed. This delay may contribute to more than half the people ill with leptospirosis hospitalised. Further, medical professionals' communication and relationship with ill people strongly colours the latter's experience, for good or for bad. Moreover, most interviewees experienced a recovery process that took several months of feeling tired, which undermined professional performance and emotional wellbeing.

A cross-sectional investigation of Leptospira at the wildlife-livestock interface in New Zealand.

There has been a recent upsurge in human cases of leptospirosis in New Zealand, with wildlife a suspected emerging source, but up-to-date knowledge on this topic is lacking. We conducted a cross-sectional study in two farm environments to estimate Leptospira seroprevalence in wildlife and sympatric livestock, PCR/culture prevalence in wildlife, and compare seroprevalence and prevalence between species, sex, and age groups. Traps targeting house mice (Mus musculus), black rats (Rattus rattus), hedgehogs (Erinaceus europaeus) and brushtail possums (Trichosurus vulpecula) were set for 10 trap-nights in March-April 2017 on a dairy (A) and a beef and sheep (B) farm. Trapped wild animals and an age-stratified random sample of domestic animals, namely cattle, sheep and working dogs were blood sampled. Sera were tested by microagglutination test for five serogroups and titres compared using a Proportional Similarity Index (PSI). Wildlife kidneys were sampled for culture and qPCR targeting the lipL32 gene. True prevalence in mice was assessed using occupancy modelling by collating different laboratory results. Infection profiles varied by species, age group and farm. At the MAT cut-point of ≥ 48, up to 78% of wildlife species, and 16-99% of domestic animals were seropositive. Five of nine hedgehogs, 23/105 mice and 1/14 black rats reacted to L. borgpetersenii sv Ballum. The sera of 4/18 possums and 4/9 hedgehogs reacted to L. borgpetersenii sv Hardjobovis whilst 1/18 possums and 1/9 hedgehogs reacted to Tarassovi. In ruminants, seroprevalence for Hardjobovis and Pomona ranged 0-90% and 0-71% depending on the species and age group. Titres against Ballum, Tarassovi and Copenhageni were also observed in 4-20%, 0-25% and 0-21% of domestic species, respectively. The PSI indicated rodents and livestock had the most dissimilar serological responses. Three of nine hedgehogs, 31/105 mice and 2/14 rats were carrying leptospires (PCR and/or culture positive). True prevalence estimated by occupancy modelling in mice was 38% [95% Credible Interval 26, 51%] on Farm A and 22% [11, 40%] on Farm B. In the same environment, exposure to serovars found in wildlife species was commonly detected in livestock. Transmission pathways between and within species should be assessed to help in the development of efficient mitigation strategies against Leptospira.

Leptospirosis in Aotearoa New Zealand: Protocol for a Nationwide Case-Control Study.

BACKGROUND: In Aotearoa New Zealand, 90% of patients with notified leptospirosis (a zoonotic bacterial disease) have been men working in agricultural industries. However, since 2008, the epidemiology of notified cases has been gradually changing, that is, more women are affected; there are more cases associated with occupations traditionally not considered high risk in New Zealand; infecting serovars have changed; and many patients experience symptoms long after infection. We hypothesized that there is a shift in leptospirosis transmission patterns with substantial burden on affected patients and their families. OBJECTIVE: In this paper, we aimed to describe the protocols used to conduct a nationwide case-control study to update leptospirosis risk factors and follow-up studies to assess the burden and sources of leptospirosis in New Zealand. METHODS: This study used a mixed methods approach, comprising a case-control study and 4 substudies that involved cases only. Cases were recruited nationwide, and controls were frequency matched by sex and rurality. All participants were administered a case-control questionnaire (study 1), with cases being interviewed again at least 6 months after the initial survey (study 2). A subset of cases from two high-risk populations, that is, farmers and abattoir workers, were further engaged in a semistructured interview (study 3). Some cases with regular animal exposure had their in-contact animals (livestock for blood and urine and wildlife for kidney) and environment (soil, mud, and water) sampled (study 4). Patients from selected health clinics suspected of leptospirosis also had blood and urine samples collected (study 5). In studies 4 and 5, blood samples were tested using the microscopic agglutination test to test for antibody titers against Leptospira serovars Hardjo type bovis, Ballum, Tarassovi, Pomona, and Copenhageni. Blood, urine, and environmental samples were also tested for pathogenic Leptospira DNA using polymerase chain reaction. RESULTS: Participants were recruited between July 22, 2019, and January 31, 2022, and data collection for the study has concluded. In total, 95 cases (July 25, 2019, to April 13, 2022) and 300 controls (October 19, 2019, to January 26, 2022) were interviewed for the case-control study; 91 cases participated in the follow-up interviews (July 9, 2020, to October 25, 2022); 13 cases participated in the semistructured interviews (January 26, 2021, to January 19, 2022); and 4 cases had their in-contact animals and environments sampled (October 28, 2020, and July 29, 2021). Data analysis for study 3 has concluded and 2 manuscripts have been drafted for review. Results of the other studies are being analyzed and the specific results of each study will be published as individual manuscripts.. CONCLUSIONS: The methods used in this study may provide a basis for future epidemiological studies of infectious diseases. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/47900.

Longitudinal Testing of Leptospira Antibodies in Horses Located near a Leptospirosis Outbreak in Alpacas.

The objectives of this study were to determine if horses located near an outbreak of leptospirosis in alpacas had Leptospira titres indicative of a previous or current infection and, if so, to determine the magnitude in change of titres over time. Further, the objective was to determine if horses with high titre results were shedding Leptospira in their urine. Blood samples were collected from twelve horses located on or next to the farm with the outbreak in alpacas, on day zero and at four subsequent time points (two, four, six and nine weeks). The microscopic agglutination test was used to test sera for five serovars endemic in New Zealand: Ballum, Copenhageni, Hardjo, Pomona and Tarassovi. A reciprocal MAT titre cut-off of ≥1:100 was used to determine positive horses. Seven out of twelve horses (58%) were positive to at least one serovar during one of the time points. Two horses recorded titres of ≥1600, one for both Pomona and Copenhageni and the other for Hardjo, and these two horses were both PCR positive for Leptospira in their urine samples. For five out of seven horses, the titres either remained the same or changed by one dilution across the sampling time points. The study confirmed endemic exposure to five endemic Leptospira serovars in New Zealand in a group of horses located near a confirmed leptospirosis outbreak in alpacas.

An evaluation of diagnostic tests in a case series of suspected leptospirosis patients seen in primary care.

AIMS: This study describes 47 presentations of suspected leptospirosis in general practice in New Zealand. Our primary aim was to assess the laboratory diagnosis of leptospirosis in these patients, by comparing polymerase chain reaction (PCR) tests, microscopic agglutination test (MAT) and culture results. METHODS: Patients suspected of leptospirosis were recruited from general practices in the Waikato (n=17) and Wairoa (n=30) between August 2011 and June 2015. Blood and urine samples were tested for leptospirosis at two diagnostic laboratories and one research laboratory using PCR tests, MAT and culture. RESULTS: Forty-seven patients were recruited for this study: 37 during the acute phase of the illness (within 10 days of symptom onset) and 10 after the acute phase. Eleven of the acute phase patients (11/37, 30%) and two of the later phase patients (2/10, 20%) returned positive leptospirosis test results. The 11 acute phase leptospirosis positive patients had the following positive diagnostic tests: PCR and paired MAT (+/- blood culture) (n=3), PCR only (+/- blood culture) (n=4), paired MAT only (n=3) and blood culture only (n=1). Urine PCR (performed only on Wairoa patients) was the only positive test for two of these patients. CONCLUSION: About a quarter of farm workers and meat workers presenting to general practice with flu-like symptoms will have leptospirosis, but they will not be diagnosed unless appropriately tested, and then they may only test positive for some of the tests available. To increase the likelihood of making a diagnosis, clinicians should order multiple laboratory tests, including blood and urine PCR and a paired MAT.

Of Mice, Cattle, and Men: A Review of the Eco-Epidemiology of Leptospira borgpetersenii Serovar Ballum.

In New Zealand (NZ), leptospirosis is a mostly occupational zoonosis, with >66% of the recently notified cases being farm or abattoir workers. Livestock species independently maintain Leptospira borgpetersenii serovar Hardjo and L. interrogans serovar Pomona, and both are included in livestock vaccines. The increasing importance in human cases of Ballum, a serovar associated with wildlife, suggests that wildlife may be an overlooked source of infection. Livestock could also act as bridge hosts for humans. Drawing from disease ecology frameworks, we chose five barriers to include in this review based on the hypothesis that cattle act as bridge hosts for Ballum. Using a narrative methodology, we collated published studies pertaining to (a) the distribution and abundance of potential wild maintenance hosts of Ballum, (b) the infection dynamics (prevalence and pathogenesis) in those same hosts, (c) Ballum shedding and survival in the environment, (d) the exposure and competency of cattle as a potential bridge host, and (e) exposure for humans as a target host of Ballum. Mice (Mus musculus), rats (Rattus rattus, R. norvegicus) and hedgehogs (Erinaceus europaeus) were suspected as maintenance hosts of Ballum in NZ in studies conducted in the 1970s-1980s. These introduced species are distributed throughout NZ, and are present on pastures. The role of other wildlife in Ballum (and more broadly Leptospira) transmission remains poorly defined, and has not been thoroughly investigated in NZ. The experimental and natural Ballum infection of cattle suggest a low pathogenicity and the possibility of shedding. The seroprevalence in cattle appears higher in recent serosurveys (3 to 14%) compared with studies from the 1970s (0 to 3%). This review identifies gaps in the knowledge of Ballum, and highlights cattle as a potential spillover host. Further studies are required to ascertain the role that wild and domestic species may play in the eco-epidemiology of Ballum in order to understand its survival in the environment, and to inform control strategies.

Molecular epidemiology of Campylobacter jejuni in a geographically isolated country with a uniquely structured poultry industry.

In New Zealand the number of campylobacteriosis notifications increased markedly between 2000 and 2007. Notably, this country's poultry supply is different than that of many developed countries as the fresh and frozen poultry available at retail are exclusively of domestic origin. To examine the possible link between human cases and poultry, a sentinel surveillance site was established to study the molecular epidemiology of Campylobacter jejuni over a 3-year period from 2005 to 2008 using multilocus sequence typing. Studies showed that 60.1 to 81.4% of retail poultry carcasses from the major suppliers were contaminated with C. jejuni. Differences were detected in the probability and level of contamination and the relative frequency of genotypes for individual poultry suppliers and humans. Some carcasses were contaminated with isolates belonging to more than one sequence type (ST), and there was evidence of both ubiquitous and supplier-associated strains, an epidemiological pattern not recognized yet in other countries. The common poultry STs were also common in human clinical cases, providing evidence that poultry is a major contributor to human infection. Both internationally rare genotypes, such as ST-3069 and ST-474, and common genotypes, such as ST-45 and ST-48, were identified in this study. The dominant human sequence type in New Zealand, ST-474, was found almost exclusively in isolates from one poultry supplier, which provided evidence that C. jejuni has a distinctive molecular epidemiology in this country. These results may be due in part to New Zealand's geographical isolation and its uniquely structured poultry industry.

Estimation of the burden of leptospirosis in New Zealand.

BACKGROUND: Human leptospirosis mainly affects people in close occupational contact with domestic livestock and their products in New Zealand. The disease has an unquantified impact on both human health and animal production in the country. This study aimed to estimate the burden of leptospirosis in terms of disability-adjusted life years (DALYs) and cost associated with loss due to absence from work, treatment of disease, animal production loss and cost of vaccination. METHODS: Previously published studies of abattoir workers farmers, and veterinarians, reporting annual risks of influenza-like illness attributable to Leptospira infection, were used to estimate the expected number of cases in a year. The cost of lost animal production was based on results of observational studies in beef cattle, sheep and deer conducted in New Zealand. RESULTS: Expected median annual number of severe and mild cases of human leptospirosis was 2,025 (95% probability interval [95% PI] 1,138-3,422). Median annual DALYs were 0.42 (95% PI: 0.06-2.40) per 100,000 people for the entire population, and 15.82 (95% PI: 2.09-90.80) per 100,000 people working in at-risk occupations (i.e. abattoir workers, farmers and veterinarians). Human infection resulted in a median cost of 4.42 (95% PI: 2.04-8.62) million US dollars (USD) due to absence from work and disease treatment. Median production loss cost in beef cattle, sheep and deer was USD 7.92 (95% PI: 3.75-15.48) million, while median vaccination cost in cattle, (including dairy), sheep and deer was USD 6.15 (95% PI: 5.30-7.03) million. Total annual cost of leptospirosis plus vaccination was USD 18.80 (95% PI: 13.47-27.15) million, equivalent to USD 440,000 (95% PI: 320,000-640,000) per 100,000 people. CONCLUSION: This study provides an estimate of the disease burden and cost of leptospirosis in New Zealand that could support occupational health authorities and livestock industries in assessing interventions for this disease.

Seroprevalence of Leptospira in Racehorses and Broodmares in New Zealand.

A cross-sectional survey was conducted to determine the seroprevalence of Leptospira in a cohort of horses and to evaluate potential risk factors for Leptospira seropositivity in horses in New Zealand. The convenience sample included 499 Thoroughbred racing and breeding horses from 25 commercial properties in North Island, New Zealand. A questionnaire was used to collect demographic data on horses and property-level information on grazing and management practices, pest (rodent) management, access to natural waterways, other livestock on the property, and possible contact with wildlife. The microscopic agglutination test was used to test sera for serovars Ballum, Copenhageni, Hardjo (bovis), Pomona, and Tarassovi. Logistic regression was used to investigate the risk factors for Leptospira seropositivity to at least one serovar and for each serovar individually. A total of 124 (25%, 95% confidence interval (CI) 21-29%) horses had positive titres to any one of the five serovars. The seroprevalence of Ballum, Copenhageni, Hardjo (bovis), Pomona, and Tarassovi was 5% (95% CI 3-7%), 9% (95% CI 7-12%), 6% (95% CI 4-8%), 6% (95% CI 4-8%), and 6% (95% CI 4-8%), respectively. Broodmares, compared to racehorses and alternately grazing horses with sheep, increased the odds of exposure to any one serovar, whilst grazing the same time as sheep and alternately grazing horses with cattle increased the odds of exposure to Ballum and Hardjo (bovis), respectively. Historical exposure to Leptospira in racing and breeding horses was identified, and risk factors were consistent with pasture-based exposure.

First evidence of concurrent enzootic and endemic transmission of Ross River virus in the absence of marsupial reservoirs in Fiji.

BACKGROUND: Ross River virus (RRV) is a zoonotic alphavirus transmitted by several mosquito species. Until recently, endemic transmission was only considered possible in the presence of marsupial reservoirs. METHODS: RRV seroprevalence was investigated in placental mammals (including horses, cows, goats, pigs, dogs, rats, and mice) in Fiji, where there are no marsupials. A total of 302 vertebrate serum samples were collected from 86 households from 10 communities in Western Fiji. RESULTS: Neutralizing antibodies against RRV were detected in 28% to 100% of sera depending on the species, and neutralization was strong even at high dilutions. CONCLUSIONS: These results are unlikely to be due to cross-reactions. Chikungunya is the only other alphavirus known to be present in the Pacific Islands, but it rarely spills over into non-humans, even during epidemics. The study findings, together with a recent report of high RRV seroprevalence in humans, strongly suggest that RRV is circulating in Fiji in the absence of marsupial reservoirs. Considering that all non-human vertebrates present in Fiji are pan-global in distribution, RRV has the potential to further expand its geographic range. Further surveillance of RRV and access to RRV diagnostics will be critical for the early detection of emergence and outbreaks.

Molecular epidemiology of Campylobacter jejuni isolates from wild-bird fecal material in children's playgrounds.

In many countries relatively high notification rates of campylobacteriosis are observed in children under 5 years of age. Few studies have considered the role that environmental exposure plays in the epidemiology of these cases. Wild birds inhabit parks and playgrounds and are recognized carriers of Campylobacter, and young children are at greater risk of ingesting infective material due to their frequent hand-mouth contact. We investigated wild-bird fecal contamination in playgrounds in parks in a New Zealand city. A total of 192 samples of fresh and dried fecal material were cultured to determine the presence of Campylobacter spp. Campylobacter jejuni isolates were also characterized by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST), and the profiles obtained were compared with those of human isolates. C. jejuni was isolated from 12.5% of the samples. MLST identified members of clonal complexes ST-45, ST-682, and ST-177; all of these complexes have been recovered from wild birds in Europe. PFGE of ST-45 isolates resulted in profiles indistinguishable from those of isolated obtained from human cases in New Zealand. Members of the ST-177 and ST-682 complexes have been found in starlings (Sturnus vulgaris) in the United Kingdom, and these birds were common in playgrounds investigated in New Zealand in this study. We suggest that feces from wild birds in playgrounds could contribute to the occurrence of campylobacteriosis in preschool children. Further, the C. jejuni isolates obtained in this study belonged to clonal complexes associated with wild-bird populations in the northern hemisphere and could have been introduced into New Zealand in imported wild garden birds in the 19th century.

Phenotypic and Genotypic Characterization of Neisseria gonorrhoeae Isolates from New Zealand with Reduced Susceptibility to Ceftriaxone.

Aim: To characterize mutations in penA, mtrR, ponA, and porBIB, considered target genes for antimicrobial resistance, in Neisseria gonorrhoeae isolates with elevated minimum inhibitory concentrations (MICs) of ceftriaxone cultured from patients in New Zealand. Results: Out of 28 isolates supplied by the Institute of Environmental Science and Research Limited (ESR), Porirua, New Zealand, 14 were found to show reduced susceptibility to ceftriaxone (MIC of 0.06 mg/L) according to criteria used by the ESR and the Australian Gonococcal Surveillance Programme (AGSP) when tested in our laboratory. Rates of resistance to ciprofloxacin, azithromycin, penicillin, and tetracycline were 100% (28/28), 7% (2/28), 36% (10/28), and 25% (7/28), respectively. Ten different penA (Penicillin binding protein 2 [PBP2]) sequences were observed. The most common mosaic penA M-1 resembled mosaic penA XXXIV, which has been associated with ceftriaxone treatment failures in other countries. Four semimosaic PBP2 sequences were observed and may be novel PBP sequences, while four out of five nonmosaic PBP2 sequences were similar to PBP2 sequences reported in Australia. Twenty-one isolates harbored mutations in all 4 genes (penA, mtrR, porBIB, and ponA), and 13 of these exhibited reduced susceptibility to ceftriaxone. Conclusion: Mutations in penA, mtrR, porBIB, and ponA observed in this study may have contributed to reduced susceptibility to ceftriaxone among New Zealand gonococcal isolates. Over half (16/22) of mosaic penA sequences from the gonococcal isolates resembled penA XXXIV.

Epidemiological investigation of Leptospira spp. in a dairy farming enterprise after the occurrence of three human leptospirosis cases.

An epidemiological investigation was conducted in an unvaccinated dairy farming enterprise in which three workers on one of the milking herds (Herd 1) were diagnosed with leptospirosis due to serovars Hardjo (H) (n = 2) and Pomona (P) (n = 1) between January and March 2015. Blood and urine samples were collected from milking cows in Herd 1 (N = 230) and Herd 2 (N = 400), rising one- (R1, N = 125) and rising two-year-old (R2, N = 130) replacement heifers, and four pigs associated with Herd 1, in March 2015. Sera were tested using the MAT for serovars H, P, Copenhageni (C), Ballum (B) and Tarassovi (T), and urine samples were tested by qPCR. Seventy-five per cent of 109 cows in Herd 1 and 36% of 121 in Herd 2 were seropositive (≥48), predominantly to H and P, and 23% of 74 cows in Herd 1 and 1% of 90 cows in Herd 2 were qPCR positive. Fifty-five per cent of 42 R2 heifers were seropositive to T. No R1 and 17% of 42 R2 heifers were qPCR positive. Subsequently, all cattle were vaccinated for H and P, and Herds 1 and 2 were given amoxicillin. After the booster vaccination, 7% of 91 in Herd 1, 2% of 82 in Herd 2 and 11% of 38 R1 heifers (sampled as R2) were PCR positive. After the amoxicillin treatment, no cows in Herd 1 and 5% of 62 cows in Herd 2 were urine PCR positive. Calves and pigs were seropositive to H, P, C and B. Vaccination and antibiotic treatment appeared effective in reducing the risk of exposure of workers to vaccine serovars. However, evidence of non-vaccine serovars indicated that workers likely remain at risk of exposure to Leptospira.

Institutional gastroenteritis outbreaks and time to notify public health services.

AIM: We report a quantification and visualisation of the association between the time to notify public health service (PHS) and the duration and size of institutional gastroenteritis outbreaks, and explore the seasonality and trend of the outbreaks. METHOD: Descriptive analysis was performed on institutional gastroenteritis outbreak data from a North Island PHS (1 January 2009-31 December 2014). Time-series analysis was used to explore the seasonality and trend of outbreaks. Multivariate analyses were performed to quantify the association between the time to notify PHS and the duration and size of outbreaks. RESULTS: One hundred and seventy-five gastroenteritis outbreaks (from 58 facilities) were included in descriptive analyses. A significant increasing trend (p=0.01) without seasonal pattern was confirmed by time-series analysis. Shorter notification time was associated with shorter duration and smaller size of outbreaks, eg, duration of outbreaks when time to notify was ≥7 days, was 3.4 days (p=0.001, 95% CI=3.1-3.7) longer than baseline time to notify (0-1 day). CONCLUSION: Prompt notification to the PHS appears to be a factor associated with reduced outbreak duration and size.

Effects of natural infection by L. borgpetersenii serovar Hardjo type Hardjo-bovis, L. interrogans serovar Pomona and leptospiral vaccination on sheep reproduction.

Most New Zealand sheep flocks are seropositive to Leptospira serovars Hardjo and/or Pomona, yet vaccination is rare. This study evaluated the impact of exposure to these serovars and of vaccination, on primiparous one- (P1) and two-year-old (P2) sheep reproduction outcomes. The study was designed as a split-flock vaccination trial, with a third of the animals vaccinated starting at one month of age. Reproduction outcomes were the proportion of bred P1 (7 months old) and as P2 (19 months old) scanned pregnant, the proportion of pregnant ewes rearing a lamb to tail docking and the proportion of docked lambs that were weaned. Odds ratios and their 95% confidence intervals were calculated to compare reproductive performance between vaccinated and control sheep, and within the control group, between seropositive and seronegative sheep. Odds ratios (OR) were also calculated to assess the relationship between vaccination and loss to follow-up. There was no difference in pregnancy and docking rates between vaccinated and control sheep, or between seropositive and seronegative sheep. P1 with a Hardjo titre ≥1536 were significantly less likely (OR = 0.41, 95%CI = 0.19-0.93) to keep a lamb between docking and weaning than P1 with both Hardjo and Pomona titres <1536, for an observed difference in weaning rate of up to 22.6% points on one farm. A reduction of weaning rates in 2-tooths seropositive for Pomona alone and both Hardjo and Pomona was observed but this was non-significant, possibly because of a lack of power. No difference in weaning rate was observed between vaccinated and control P1 or P2. On one farm vaccinated P1 were less likely to be lost to follow-up (OR = 0.27, 95% CI 0.08 to 0.95) between breeding and weaning. Comparing reproductive performance of vaccinated and control sheep revealed no significant difference. However, comparing exposed and non-exposed ewes revealed a possible adverse effect of Leptospira on weaning rates. This suggests that a full vaccination program may result in an improvement of reproductive outcomes, possibly by providing herd immunity.

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.