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Leptospirosis is a global zoonosis that in New Zealand affects primarily people occupationally exposed to livestock. The objective of this study was to estimate the seroprevalence of five Leptospira serovars in farmers working on cattle, sheep and deer farms that had the serological status of animals previously assessed and to identify risk factors for farmer seropositivity. A total of 178 farmers from 127 properties participated in the study. Blood samples were tested using the microscopic agglutination test (MAT) for the presence of antibodies to Leptospira. Samples with a MAT titre ≥48 were considered seropositive. Using Bayesian statistical analysis, the median seroprevalence of Leptospira, all serovars combined, was estimated to be 6.6% (95% probability interval (PI) 3.6-10.9%). Risk factors associated with seropositivity were assisting deer or cattle calving, farming deer, having ≥25% of flat terrain and high abundance of wild deer on farm, while high possum abundance on farm was negatively associated with seropositivity. No association was observed between farmer serostatus and previously recorded livestock serology. Leptospira seropositivity was associated with influenza-like illness of farmers (RR = 1.7; 95% PI 1.0-2.5). Assuming a causal relationship, this suggested an annual risk of 1.3% (95% PI 0.0-3.0%) of influenza-like illnesses due to Leptospira infection in the population of farmers. The association between seropositivity and disease can be used to estimate the public health burden of leptospirosis in New Zealand. Identifying and understanding risk factors for Leptospira seropositivity can inform preventive measures, hence contributing to the reduction of leptospirosis incidence in farmers. [ABSTRACT FROM AUTHOR]

Background Decreased efficacy of antimicrobials and increased prevalence of multidrug resistance ( MDR) is of concern worldwide. Objectives To describe and analyze bacterial culture and antimicrobial susceptibilities from respiratory samples submitted from young horses (4 weeks to 3 years old). Animals Samples from 289 horses were submitted to a commercial laboratory. Methods A retrospective database search of submissions made to a New Zealand veterinary laboratory between April 2004 and July 2014. The results of in vitro susceptibility testing by Kirby-Bauer disc diffusion were described and tabulated for the major bacterial species isolated. Multiple correspondence analysis ( MCA) was used to describe the clustering of MDR isolates and selected demographic variables. Results Overall, 774 bacterial isolates were cultured from 237 horses, the majority of these isolates were gram-positive (67.6%; 95% CI 64.3-70.9%). Streptococcus spp. were the most common genus of bacteria isolated and were 40.1% (95% CI 36.6-43.5%) of the isolates cultured. Susceptibility of Streptococcus spp. to penicillin, gentamicin, and ceftiofur was >85%. Overall, gram-negative susceptibility to ceftiofur, tetracycline, and TMPS was <75%. MDR was defined as resistance to 3 or more antimicrobials, and was found in 39.2% of horses (93/237; 95% CI 33.0-45.5%). Conclusions and clinical importance Culture and susceptibility results have highlighted that MDR is an emerging problem for young horses in New Zealand (NZ), where a bacterial respiratory infection is suspected. This should be considered when prescribing antimicrobials, and emphasizes the need for submission of samples for culture and susceptibility. [ABSTRACT FROM AUTHOR]

A cross-sectional study was carried out on sheep and cattle slaughtered at a New Zealand abattoir from September to November 2010 to investigate the supplier-specific shedding rate, renal carriage rate and seroprevalence of leptospires. In the 2008/2009 season, this abattoir experienced three human leptospirosis cases from 20 staff, of which two were hospitalized. Urine, kidney and blood samples were collected from carcasses of 399 sheep (six suppliers, 17 slaughter lines) and 146 cattle (three suppliers, 22 slaughter lines). The urine and kidney samples were tested by quantitative real-time PCR (q PCR), while serum samples (from coagulated blood samples) were tested by microscopic agglutination test ( MAT). In total, 27% (73/274; 95% CI: 18-37) of urine samples tested positive by q PCR. Species-specific shedding rates (prevalence of positive urine q PCR) were 31% (95% CI: 17-48) for sheep and 21% (95% CI: 14-30) for cattle. For 545 kidney samples tested, 145 were q PCR positive (27%; 95% CI: 17-39). The average prevalence of kidney q PCR positivity was 29% (95% CI: 17-45) for sheep and 21% (95% CI: 15-28) for cattle. Three hundred and thirty of 542 sampled sheep and cattle had antibodies against Leptospira borgpetersenii serovar Hardjobovis (Hardjobovis) and/or Leptospira interrogans serovar Pomona (Pomona), based on reciprocal MAT titre ≥1 : 48 (overall seroprevalence of 61%; 95% CI: 48-73). Seroprevalence was 57% (95% CI: 40-72) for sheep and 73% (95% CI: 59-83) for cattle. Among the seropositive animals, 41% (70/170; 95% CI: 30-54) were shedding (tested positive by urine q PCR) and 42% (137/330; 95% CI: 30-54) had renal carriage (tested positive by kidney q PCR). Some risk management options for abattoirs or farms to prevent human leptospirosis infections include vaccination of maintenance hosts, the use of personal protective equipment, and the application of urine q PCR to detect shedding status of stock as surveillance and as an alert. [ABSTRACT FROM AUTHOR]

The national control programme for Salmonella in Danish swine herds introduced in 1993 has led to a large decrease in pork-associated human cases of salmonellosis. The pork industry is increasingly focused on the cost-effectiveness of surveillance while maintaining consumer confidence in the pork food supply. Using national control programme data from 2003 and 2004, we developed a zero-inflated binomial model to predict which farms were most at risk of Salmonella. We preferentially sampled these high-risk farms using two sampling schemes based on model predictions resulting from a farm's covariate pattern and its random effect. Zero-inflated binomial modelling allows assessment of similarities and differences between factors that affect herd infection status (introduction), and those that affect the seroprevalence in infected herds (persistence and spread). Both large (producing greater than 5000 pigs per annum), and small herds (producing less than 2000 pigs per annum) were at significantly higher risk for infection and subsequent seroprevalence, when compared with medium sized herds (producing between 2000 and 5000 pigs per annum). When compared with herds being located elsewhere, being located in the south of Jutland significantly decreased the risk of herd infection, but increased the risk of a pig from an infected herd being seropositive. The model suggested that many of the herds where Salmonella was not detected were infected, but at a low prevalence. Using cost and sensitivity, we compared the results of our model based sampling schemes with those under the standard sampling scheme, based on herd size, and the recently introduced risk-based approach. Model-based results were less sensitive but show significant cost savings. Further model refinements, sampling schemes and the methods to evaluate their performance are important areas for future work, and these should continue to occur in direct consultation with Danish authorities. [ABSTRACT FROM AUTHOR]

Reasons for performing study Decreased efficacy of veterinary antimicrobials and increased prevalence of multi-drug resistance ( MDR) is of concern, but little is known of antimicrobial resistance encompassing the New Zealand ( NZ) equine population. Recent concerns have arisen over the emergence of multi-resistant bacteria [1], especially on NZ stud farms where antibiotics are frequently used for respiratory disease without veterinary input [2]. Objectives To describe bacterial culture and antimicrobial sensitivity results from respiratory samples submitted of young horses (4 weeks to 3 years old). Study design Retrospective study of clinical pathology records. Methods A database search for isolates and sensitivity of respiratory samples from young horses ( April 2004- July 2014) was conducted. The results of in vitro sensitivity testing by Kirby-Bauer disk diffusion were tabulated for major bacterial species isolated. Multiple correspondence analysis was used to describe clustering of multi-drug resistance ( MDR) and selected demographic variables. Results 237/289 eligible respiratory samples had at least one aerobic bacterial isolate. Most of the 774 bacterial isolates were Gram-positive (68%). Streptococcus species were the most common genus isolated (40% of isolates). Sensitivity of Streptococcus spp. to penicillin, gentamicin and ceftiofur was >85%, but only 53% to trimethoprim-sulfamethoxone. Gram-negative sensitivity to ceftiofur, tetracycline, and trimethoprim-sulfamethoxone was <75%. MDR was found for 16% of isolates and in 39% of horses. Conclusions Penicillin is an appropriate first-line antimicrobial for use in most NZ young horses with suspected bacterial respiratory infection. However, based on findings of MDR, submission of samples for culture and monitoring of sensitivity should be used to inform antimicrobial selection. Ethical animal research: Not applicable. Sources of funding: Massey University McGeorge Fund; New Zealand Equine Research Foundation. Competing interests: None declared. [ABSTRACT FROM AUTHOR]

Reasons for performing study Guidelines for the rational use of antimicrobials enable practitioners to improve antimicrobial stewardship and slow the development of antimicrobial resistance ( AMR) [1]; these must be regionally relevant [2]. New Zealand ( NZ) is geographically isolated and the importance of AMR on equine studs is unknown. Objectives To identify AMR patterns of bacteria isolated from NZ foals so as to provide regionally specific information for the development of antimicrobial stewardship guidelines. Study design Retrospective study of clinical pathology records. Methods A database search of bacterial culture submissions from foals <3 weeks of age from April 2004 to December 2013 was completed. Culture results, antimicrobial sensitivities, and demographic factors were tabulated. The Kirby-Bauer disk diffusion susceptibility test was used to define sensitivity. Multi-drug resistance ( MDR) was defined as non-sensitivity to 3 or more core antimicrobials in a panel (ceftiofur, enrofloxaxin, gentamicin, penicillin [not included for Gram-negative bacteria], tetracycline, trimethoprim- sulfamethoxazole). Results Bacterial isolates (n = 127) were cultured from 64/102 (62.7%) of foal submissions. Four bacterial groups ( Staphylococcus spp., Streptococcus spp., Enterococcus spp. and Escherichia coli) accounted for 100 (79%) of bacterial isolates cultured. At least one or 2 MDR isolates were cultured from 24 (38%) and 8 (12%) foals, respectively. Culture positive and negative foals were demographically similar. Conclusions A significant number of bacterial isolates from foals have reduced antimicrobial susceptibility to commonly used antimicrobial drugs. The results are of concern from treatment and stewardship perspectives. Multi-drug resistance was found, indicating a need for regionally relevant antimicrobial use recommendations. Ethical animal research: Not applicable. Sources of funding: Massey University McGeorge fund; New Zealand Equine Research Foundation. Competing interests: None declared. [ABSTRACT FROM AUTHOR]