A novel Bayesian Latent Class Model (BLCM) evaluates multiple continuous and binary tests: A case study for Brucella abortus in dairy cattle.

Bovine brucellosis, primarily caused by Brucella abortus, severely affects both animal health and human well-being. Accurate diagnosis is crucial for designing informed control and prevention measures. Lacking a gold standard test makes it challenging to determine optimal cut-off values and evaluate the diagnostic performance of tests. In this study, we developed a novel Bayesian Latent Class Model that integrates both binary and continuous testing outcomes, incorporating additional fixed (parity) and random (farm) effects, to calibrate optimal cut-off values by maximizing Youden Index. We tested 651 serum samples collected from six dairy farms in two regions of Henan Province, China with four serological tests: Rose Bengal Test, Serum Agglutination Test, Fluorescence Polarization Assay, and Competitive Enzyme-Linked Immunosorbent Assay. Our analysis revealed that the optimal cut-off values for FPA and C-ELISA were 94.2 mP and 0.403 PI, respectively. Sensitivity estimates for the four tests ranged from 69.7% to 89.9%, while specificity estimates varied between 97.1% and 99.6%. The true prevalences in the two study regions in Henan province were 4.7% and 30.3%. Parity-specific odds ratios for positive serological status ranged from 1.2 to 2.2 for different parity groups compared to primiparous cows. This approach provides a robust framework for validating diagnostic tests for both continuous and discrete tests in the absence of a gold standard test. Our findings can enhance our ability to design targeted disease detection strategies and implement effective control measures for brucellosis in Chinese dairy farms.

The Effect of Lameness on Milk Production of Dairy Goats.

Lameness on dairy goat farms is a welfare concern and could negatively affect milk production. This study's objective was to evaluate the effects of clinical lameness on the daily milk production of dairy goats. Between July 2019 and June 2020, 11,847 test-day records were collected from 3145 goats on three farms in New Zealand. Locomotion scoring of goats used a five-point scoring system (0 to 4). The dataset was split into two groups by lactation type, where goats were classified as being in seasonal lactation (≤305 days in milk) or extended lactation (>305 days in milk). A linear mixed model was used to analyze datasets using milk characteristics as the dependent variables. Severely lame goats (score 4) in seasonal and extended lactation produced 7.05% and 8.67% less milk than goats not lame, respectively. When the prevalence of severe lameness is between 5 and 20% of the herd, the estimated average daily milk income lost was between NZD 19.5 and 104 per day. This study established the negative impact of lameness on milk production and annual income in dairy goats on three farms.

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.

Ultrasonographic features of the regressing yolk sac of normal captive Brown kiwi chicks (Apteryx mantelli) vary with age.

Brown kiwi (Apteryx mantelli) are a culturally significant ratite species endemic to New Zealand. Chicks can develop diseases of the yolk sac which can be fatal if not promptly recognized and treated. Ultrasound examination of the yolk sac is an important component in the evaluation of chicks with suspected yolk sac disease. However, there are currently no reports of the normal ultrasonographic appearance of the regressing yolk sac in this species. The objective of this prospective reference interval study was to describe the normal ultrasonographic appearance of the yolk sac in brown kiwi chicks. Focused coelomic sonographic examinations were performed on 29 healthy chicks from >1 day of age until the yolk sac was completely absorbed or was <1 mL in volume. 41.6% (57/137) of yolks were round/ovoid in shape and 58.6% (80/137) had lobulated margins with invaginations. All yolks (137/137) were hyperechoic relative to adjacent coelomic structures. The heterogeneity of the echogenicity of the yolk was significantly associated with age (increased heterogeneity in younger birds) and was homogeneous, mildly heterogeneous, and moderately heterogeneous in 33% (46/138), 46% (63/138), and 21% (29/138) of all examinations respectively. Intrasac anechoic pockets were seen in 14% (20/139) of yolk sacs. The rate of yolk sac resorption slowed with age. In all examinations identifying a completely absorbed yolk sac or a yolk sac <1 mL in volume, chicks were less than 21 days old. The results of this study provide a reference of normal for the sonographic appearance of the yolk sac in captive brown kiwi chicks.

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.

Estimates of Genetic Parameters for Milk, the Occurrence of and Susceptibility to Clinical Lameness and Claw Disorders in Dairy Goats.

The New Zealand goat industry accesses niche markets for high-value products, mainly formula for infants and young children. This study aimed to estimate the genetic parameters of occurrence and susceptibility of clinical lameness and selected claw disorders and establish their genetic associations with milk production traits. Information on pedigree, lameness, claw disorders, and milk production was collected on three farms between June 2019 and July 2020. The dataset contained 1637 does from 174 sires and 1231 dams. Estimates of genetic and residual (co)variances, heritabilities, and genetic and phenotypic correlations were obtained with uni- and bi-variate animal models. The models included the fixed effects of farm and parity, deviation from the median kidding date as a covariate, and the random effects of animal and residual error. The heritability (h2) estimates for lameness occurrence and susceptibility were 0.07 and 0.13, respectively. The h2 estimates for claw disorder susceptibilities ranged from 0.02 to 0.23. The genotypic correlations ranged from weak to very strong between lameness and milk production traits (-0.94 to 0.84) and weak to moderate (0.23 to 0.84) between claw disorder and milk production traits.

Molecular characterisation and additional morphological descriptions of Eimeria spp. (Apicomplexa: Eimeriidae) from brown kiwi (Apteryx mantelli Bartlett).

Brown kiwi (Apteryx mantelli Bartlett), a ratite endemic to New Zealand, is currently listed as "Vulnerable" under the IUCN classification system due to predation by introduced mammals. Operation Nest Egg (ONE) raises chicks and juveniles in predator-proof enclosures until they are large enough to defend themselves. These facilities experience an environmental accumulation of coccidial oocysts, which leads to severe morbidity and mortality of these kiwi. Four species of coccidia have been morphologically described from sporulated oocysts with additional opportunistic descriptions of endogenous stages. This research continues the morphological descriptions of these species of Eimeria with an additional novel morphotype also morphologically described. It also provides the first genetic characterisation targeting the mitochondrial cytochrome c oxidase I (COI) gene. Based on these findings, it was determined there are at least five morphotypes of Eimeria that infect brown kiwi and co-infections are common at the ONE facilities surveyed. The COI amplicon targeted for this study was sufficient to provide differentiation from other members of this genus. Sanger sequencing yielded ambiguous bases, indicating the need for more in-depth sequencing.

Evaluating the Behavioural Responses of Healthy Newborn Calves to a Thoracic Squeeze.

A thoracic squeeze has been observed to cause low-vigour neonates of various farmed mammal species, including calves, to enter a state of reduced responsiveness. The removal of the squeeze causes rapid recovery and the expression of normal, healthy behaviours. However, the responses of healthy calves to a thoracic squeeze have not yet been characterized. The responses of 16 healthy newborn calves to a thoracic squeeze are described, along with the effect of the squeeze's application method on the response. Calves aged between 12 and 36 h were subjected to the squeeze using a rope (n = 8) or an inflation cuff (n = 8). In total, 13 of the 16 calves were induced into a state of reduced responsiveness, though neural reflexes persisted in nearly all of them. The squeeze was discontinued for nearly half of those induced before the end of the 10-min period, either due to spontaneous arousal or physiological instability. Both methods of application were equally effective at inducing reduced responsiveness, though responses to the cuff appeared to be more rapid than those to the rope. These findings support previous research on piglets and foals, and suggest that the behavioural responses to a thoracic squeeze are generalised across neonates of precocial farmed mammals; the findings provide a foundation for further research exploring the mechanisms underlying the response and the benefits that its application may bring for the performance of husbandry procedures.

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.

Characterisation of the Behavioural Effects of a Thoracic Squeeze in Healthy Newborn Piglets.

A thoracic squeeze has been observed to cause both healthy and low vigour neonatal foals to enter a 'less-responsive state', characterised by loss of posture, eye closure and cessation of movement, from which they rapidly recover to express normal healthy behaviours when the squeeze is released. To date, there have been no systematic studies characterising the responses of healthy neonates of other mammalian species to a thoracic squeeze. We describe the responses of healthy newborn piglets (n = 17) to a standardised application of the thoracic squeeze and evaluate the effect of the method of squeeze application on the response. Neonatal piglets were squeezed around the chest with either a soft fabric rope as has been used in foals (n = 8) or a novel purpose-made inflation cuff (n = 9). Both methods were effective at inducing a less-responsive behavioural state in all piglets, with neural reflexes reduced or absent in over half of them. The inflation cuff appeared to induce the less-responsive state faster than the rope, and more piglets squeezed with the cuff remained in this state for the full 10-min squeeze. These findings suggest that the behavioural response of foals to thoracic squeezing can be generalised to neonates of other precocial mammalian species. This initial study provides a foundation for further research using the inflation cuff to explore mechanisms underlying the thoracic squeeze and ways in which it may be applied whilst performing husbandry procedures.

Detection of Foot-and-Mouth Disease Virus in the Absence of Clinical Disease in Cattle and Buffalo in South East Asia.

Foot-and-mouth disease virus (FMDV) is widespread throughout much of the world, including parts of South East Asia. Surveillance is often limited in endemic areas, relying predominantly on passive outbreak reporting. As part of the World Organisation for Animal Health (OIE)'s South East Asia and China Foot-and-Mouth Disease Project (SEACFMD), field sampling was performed to help understand evidence of widespread virus exposure observed in previous studies. Serum and dry mucosal swabs were collected to evaluate the presence of FMDV RNA on the nasal, oral, and dorsal nasopharyngeal mucosal surfaces of 262 healthy cattle (n = 84 in Laos; n = 125 in Myanmar) and buffalo (n = 48 in Laos; n = 5 in Myanmar) immediately following slaughter in three slaughterhouses. Swabs and serum were tested by the OIE/FAO World Reference Laboratory for foot-and-mouth disease (WRLFMD) using pan-serotypic real-time reverse transcription-PCR (rRT-PCR) and serum was evaluated using the FMD PrioCHECK non-structural protein (NSP) ELISA. In total, 7.3% of animals had detectable FMDV RNA in one or more of the three sites including 5.3% of nasopharyngeal swabs, 2.3% of oral swabs, and 1.5% of nasal swabs. No FMDV RNA was detected in serum. Overall, 37.8% of animals were positive for NSP antibodies, indicating likely past natural exposure to FMDV. Results were comparable for Laos and Myanmar, and for both cattle and buffalo, and were not significantly different between age groups. Detectable FMDV RNA present on the oral and nasal mucosa of clinically-healthy large ruminants in Laos and Myanmar demonstrates the importance of sampling asymptomatic animals as part of surveillance, and may indicate that subclinical infection plays a role in the epidemiology of FMD in these countries.

SEABIRDS AS POSSIBLE RESERVOIRS OF ERYSIPELOTHRIX RHUSIOPATHIAE ON ISLANDS USED FOR CONSERVATION TRANSLOCATIONS IN NEW ZEALAND.

Erysipelothrix rhusiopathiae, the causative agent of the disease erysipelas, is a gram-positive bacillus, and an opportunistic pathogen in diverse species of animals. In New Zealand, E. rhusiopathiae has killed endangered birds on offshore islands, including Kakapo (Strigops habroptilus), Takahe (Porphyrio hochstetteri), and Kiwi (Apteryx spp.). The source of infection is uncertain, and the prevalence of E. rhusiopathiae among wild birds is currently unknown. During October 2018 to December 2018, we surveyed dead and live seabirds that visit two of New Zealand's offshore islands used for Kakapo conservation with the goal of determining the prevalence of E. rhusiopathiae. Bone marrow from dead birds was cultivated on selective agar, and organisms cultured were identified using matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry. The prevalence of E. rhusiopathiae was calculated in different species for each island. We surveyed live birds using PCR with Erysipelothrix spp.-specific primers on blood samples. The prevalence of E. rhusiopathiae in dead seabirds on Whenua Hou and Te Hauturu-o-Toi was 3.4% (3/86) and 11.4% (5/44), respectively. On Whenua Hou, E. rhusiopathiae was detected in Sooty Shearwaters (Puffinus griseus; 5.9%, 2/34) and Mottled Petrels (Pterodroma inexpectata; 2.7%, 1/36) while it was detected only in Cook's Petrels (Pterodroma cookie; 13.5%, 5/37) on Te Hauturu-o-Toi. Blood samples were collected from two seabird species; only one of 50 Mottled Petrels (2.0%) was positive for the presence of Erysipelothrix spp. Our findings confirm that burrowing seabirds are possible reservoirs of E. rhusiopathiae on both islands studied and may be the source of spillover to other species on the island. The differences in observed prevalence suggest the species composition of the reservoir of E. rhusiopathiae may vary geographically.

Comparing the Mini-FLOTAC and centrifugal faecal flotation for the detection of coccidia (Eimeria spp.) in kiwi (Apteryx mantelli).

Coccidia (Eimeria spp.) in brown kiwi (Apteryx mantelli) cause significant morbidity and mortality in captive rearing facilities. Monitoring the abundance of this parasite in individual birds is crucial for successful management of kiwi. This research compares the abilities of centrifugal faecal flotations (CFF) and a modified Mini-FLOTAC protocol to detect oocysts. We hypothesised that the Mini-FLOTAC would detect higher oocyst counts. Kiwi dropping samples (n = 10) were homogenized in MgSO4 (SG 1.28) and oocyst counts made with CFFs and Mini-FLOTAC counting chambers, with three replicates for each method. For CFF, 0.5 g of droppings were examined using standard methods. Mini-FLOTAC counts were made using a modified sample preparation compared with the manufacturer's protocol but still used a 1:20 dilution of droppings. Oocysts were quantified using light microscopy at ×100-300 magnification. A linear mixed-effects model by REML showed that oocyst per gram estimates via the Mini-FLOTAC method were 3.2 times higher (95% CI 2.4-4.5, p < 0.01) than the CFF results. This increased detection likely represents a more accurate estimation of parasite shedding and should be considered for use in research or applications requiring more accuracy, cost-effectiveness, or accessibility than the CFF provides.

Owner and Cat-Related Risk Factors for Feline Overweight or Obesity.

Feline obesity is a highly prevalent disease that poses an urgent and serious challenge. Attempted treatment by weight reduction is often unsuccessful; a new preventative approach that focuses on the role of the owner may be helpful. This study used data collected from an international survey of cat owners designed to assess owner personality and self-control, owner-pet attachment, feeding practices, and the cat's body condition. Owner-reported body condition scores (BCS) of cats were assessed using images adapted from a 5-point BCS system and categorized as a binary dependent variable: overweight/obese (BCS 4-5) and not overweight (BCS 1-3). Owner-reported BCS scores using a verbal BCS scale were also used as a binary dependent variable. Of the 6,835 respondents, 30.5% described their cat as overweight/obese using the visual BCS scale, and 32.5% using the verbal scale. Multivariable logistic regression models were built using stepwise-backward selection. A total of 8 variables were significant using the visual score as the dependent variable, while 11 variables were significant using the verbal score as the dependent variable (p < 0.05). Low owner conscientiousness was associated with an increased risk of feline overweight/obesity (OR = 1.23, 95% CI 1.10-1.38), whereas preference for delayed reward was associated with a decreased risk (OR = 0.84, 95% CI 0.75-0.96). Contrary to expectation, indulgent (OR = 0.76, 95% CI 0.53-0.91) and inconsistent (OR = 0.86, 95% CI 0.76-0.93) feeding practices appeared protective. Other significant variables (p < 0.05) included cat-related factors (age, gender, housing, source) and management-related factors (dry diet, supermarket dry diet, raw diet, stealing, hunting, and measuring food with a scoop). A third multivariable analysis was performed, using results from cats classified as overweight/obese using both scoring methods, compared with cats classified as a healthy weight using both scoring methods. A total of 10 variables were found to be significant (p < 0.05). There was significant overlap of results from all three analyses. The results of this study indicate that feline obesity is a complex problem, with many contributing risk factors. It is essential to recognize the importance of owner characteristics, and that the prevention of obesity in cats may require the development of a range of interventional strategies.

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.

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

In New Zealand, up to 97% of NZ sheep flocks are seropositive to Leptospira borgpetersenii serovar Hardjo and/or Leptospira interrogans Pomona, yet vaccination is rare. This study evaluated the impact of exposure to these serovars and of vaccination on sheep growth. One third of 2260 ewe lambs on eight farms were randomly selected and vaccinated with a primary and booster bivalent Hardjo and Pomona vaccine starting at one month of age on seven farms and at around five months of age on one farm. Repeated blood samples were taken over one (n = 6 farms, bred as ewe lambs at 7-8 months of age) or two (n = 2 farms, bred as rising 2-year-old ewes) years and tested by microscopic agglutination test to assess exposure to Hardjo and Pomona. Individual weights were recorded at the same time and modelled using a multilevel linear model accounting for within-farm clustering and repeated measures. Predicted average weights were computed and compared based on the vaccination status and within the control group based on exposure status (positive for Hardjo only, Pomona only, Hardjo and Pomona and negative) for each combination of farm and weighing episode. Statistical significance of the comparison was evaluated after adjustment for multiple comparisons. There was no difference in average weight between vaccinated and control sheep before or after vaccination in any of the flocks. The comparison between sheep seropositive for either or both serovars and seronegative sheep was inconclusive, with variations of direction and magnitude of the difference between farms and weighing episodes. In the absence of an overall growth response to vaccination, widespread adoption of vaccination would unlikely yield an economic response at the industry level. However, the inconsistency observed when comparing animals based on their exposure status suggests that the actual effect of leptospirosis on growth is difficult to predict. A study of the effect on sheep reproduction is needed to fully assess the effect of vaccination on sheep production.

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.

First report of Toxoplasma gondii sporulated oocysts and Giardia duodenalis in commercial green-lipped mussels (Perna canaliculus) in New Zealand.

Pollution of marine ecosystems with the protozoan parasites Toxoplasma gondii, Cryptosporidium spp. and Giardia duodenalis can be studied using bivalve shellfish as biosentinels. Although evidence suggests that these parasites are present in New Zealand coastal waters, the extent of protozoal pollution has not been investigated. This study used optimised molecular methods to detect the presence of Cryptosporidium spp., G. duodenalis and T. gondii in commercially sourced green-lipped mussel (Perna canaliculus), an endemic species found throughout coastal New Zealand. A nested polymerase chain reaction was validated for detection of T. gondii DNA and applied to 104 commercially sourced mussels. Thirteen mussels were positive for T. gondii DNA with an estimated true prevalence of 16.4% using Bayesian statistics, and the presence of T. gondii in mussels was significantly associated with collection during the summer compared with that in the winter (P = 0.003). Consumption of contaminated shellfish may also pose a health risk for humans and marine wildlife. As only sporulated T. gondii oocysts can be infectious, a reverse transcriptase-polymerase chain reaction was used to confirm presence of a sporozoite-specific marker (SporoSAG), detected in four mussels. G. duodenalis assemblage B, known to be pathogenic in humans, was also discovered in 1% mussels, tested by polymerase chain reaction (n = 90). Cryptosporidium spp. was not detected in the sampled mussel haemolymph. Results suggest that New Zealand may have high levels of coastal contamination with T. gondii, particularly in summer months, and that naturally exposed mussels can ingest and retain sporulated oocysts, further establishing shellfish consumption as a health concern.

68Ga-DOTATATE Uptake in Ischemic Stroke.

A 76-year-old man known to have a pancreatic neuroendocrine tumor with hepatic and lymph nodes metastasis had a follow-up Ga-DOTATATE PET/CT before Lu-DOTATATE therapy. A new cerebral lesion expressing somatostatin receptors was discovered in the right temporal lobe, suggestive of an ischemic stroke territory. This was later confirmed from the hospital chart where an ischemic stroke was described a month ago.

Effectiveness of a commercial leptospiral vaccine on urinary shedding in naturally exposed sheep in New Zealand.

L. borgpetersenii serovar Hardjo and L. interrogans serovar Pomona are endemic in New Zealand sheep. An effective vaccine and vaccination strategy would protect both humans and livestock. Four to 12 lambs were selected from each of eight farms (total=84, vaccinated group), while four to 16 lambs (total=98) served as unvaccinated controls. A commercial Hardjo/Pomona vaccine was given at 1-6 weeks of age, 5-11 weeks later and 33-67 weeks later on seven farms and at 18 weeks of age and 5 weeks later on the eighth farm. Vaccinates and controls were grazed together. Blood was regularly collected from the control group to assess flock exposure. Urine was collected from both groups 26-82 weeks after the second vaccination and tested by quantitative PCR. Seroprevalence in controls at the time of urine sampling ranged from 2.7 to 98.2% for Hardjo and from 0 to 54.1% for Pomona with seroconversion occurring 13 to 67 weeks after the second vaccination in all but one farm where exposure had happened by the time of vaccination. The shedding prevalence adjusted for clustering in farms was 45.1% [95% CI 17.6-72.7] (for an observed number of 50/98) in the control animals and 1.8% [95% CI 0.0-10.1] (for an observed number of 5/84) in the vaccinated animals. The vaccine was 100% effective on five farms where animals were vaccinated before 12 weeks of age and before natural exposure occurred, but the effectiveness was 80% [0-97] on one farm where the lambs were exposed before vaccination and 65% [9-87] to 80% [0-97] on one farm where the animals were fully vaccinated by 24 weeks of age. The overall vaccine effectiveness was 86.3% [63.6-94.8%] despite maternal antibodies in some flocks at first vaccination. Vaccination timing seemed to be crucial in achieving optimum reduction in shedding in urine in vaccinated sheep.