Cross-sectional study of canine leptospirosis in animal shelter populations in mainland Australia

OBJECTIVE: To measure the prevalence of canine leptospirosis in Queensland and to detect infection, if present, in New South Wales, Victoria, South Australia, Western Australia and the Northern Territory by measuring the serological titres of dogs held in animal shelters. PROCEDURE: Samples were collected through stratified sampling from multiple dog shelters in Queensland and New South Wales, and from one dog shelter located in close proximity to a major urban area in Victoria, South Australia, the Northern Territory and Western Australia. All samples were analysed using the microscopic agglutination test at the WHO/FAO/OIE Collaborating Centre for Reference & Research on Leptospirosis, Queensland Health Scientific Services in Brisbane, Queensland. RESULTS: Of a total of 956 samples submitted, 18 (1.9%) had positive leptospirosis titres. True prevalence measured in Queensland was estimated to be 2.5%, and the true prevalence in New South Wales, Victoria, South Australia, Western Australia and the Northern Territory was estimated to be 2.3%, 2.8%, 0%, 1% and 1.1% respectively. An association was found between seropositive status and female dogs (odds ratio (OR) 1.92) and seropositive status and the age group 1 to < 3 years (OR 1.41). Although 11 different serovars were detected, Leptospira interrogans serovar Copenhageni was the most prevalent and was found in 4 of the 18 positive dogs as a single infection. CONCLUSION: Serological evidence of canine leptospirosis in five states in mainland Australia indicates that the disease is more broadly distributed than previously thought.     

Clinical features of psoroptic mange in cattle in England and Wales

The clinical signs, treatments used and spread of psoroptic mange in cattle from October 2007 until March 2011 are described. The disease was first diagnosed in South West Wales, having not been reported in Great Britain since the 1980s. The likely source was identified as a farm that had imported two animals from mainland Europe in the summer of 2006. Since that time, disease has been diagnosed on a further 22 premises, the majority in South West Wales but also in South East and Mid Wales and on one farm in England. Bought in animals harbouring the Psoroptes species mite but not showing clinical signs were considered the greatest risk of introducing the infestation into a herd. This, together with the difficulties of treatment to eliminate the parasite, means that it is unlikely that this outbreak has been controlled. There is also a continuing threat of importing the disease from abroad. The disease is not notifiable in the UK.     

Hydatid disease in Whales: 1. Epidemiology

The literature on the epidemiology of hydatid disease in domesticated animals in Wales is reviewed and the results of a recent survey in a restricted area of Mid Wales summarised. In this survey the epidemiology of hydatid disease was studied with a view to the formulation of methods of control.     

Epidemiology of Toxocariasis in England and Wales

Toxocara infection occurs through ingestion of parasite eggs excreted by dogs and cats, and can cause severe morbidity. The burden of disease in England and Wales is not well described, and the impact of public health campaigns conducted in the mid‐1990s is uncertain. This paper uses data from two extensive databases to explore the trends in this disease in England and Wales from the 1970s to 2009.     

Sensitivity and specificity of pooled faecal culture and serology as flock-screening tests for detection of ovine paratuberculosis in Australia

The flock-level sensitivity of pooled faecal culture and serological testing using AGID for the detection of ovine Johne’s disease-infected flocks were estimated using non-gold-standard methods. The two tests were compared in an extensive field trial in 296 flocks in New South Wales during 1998. In each flock, a sample of sheep was selected and tested for ovine Johne’s disease using both the AGID and pooled faecal culture. The flock-specificity of pooled faecal culture also was estimated from results of surveillance and market-assurance testing in New South Wales.

The overall flock-sensitivity of pooled faecal culture was 92% (95% CI: 82.4 and 97.4%) compared to 61% (50.5 and 70.9%) for serology (assuming that both tests were 100% specific). In low-prevalence flocks (estimated prevalence <2%), the flock-sensitivities of pooled faecal culture and serology were 82% (57 and 96%) and 33% (19 and 49%), respectively, compared to 96% (85 and 99.5%) and 85% (72 and 93%), respectively, in higher-prevalence flocks (estimated prevalence ≥2%). A Bayesian approach incorporating prior knowledge on flock-specificity of pooled culture produced similar estimates and probability intervals. These estimates assume conditional independence of the two tests, and therefore might have over-estimated the true flock-sensitivities of the tests if the flock-sensitivities of pooled faecal culture and serology were correlated.

The estimated minimum flock-specificity of pooled culture when used for surveillance and assurance testing was 99.1% (96.9 and 99.9%). Surveillance and assurance programs in Australia are designed to provide a flock-sensitivity of 95% for an assumed prevalence of 2%. Pooled faecal culture is performing at close to this level—whereas the flock-sensitivity of serology appears to be lower than expected, particularly in lower prevalence flocks.     

A case-control study to identify farm factors affecting fertility of dairy herds: univariate description of factors

Objective To identify farm factors which were associated with reproductive performance in dairy herds in New South Wales.
Procedure A survey was administered by face to face interview to examine the responses of producers drawn from 757 herds, which used the New South Wales Agriculture Department Dairy Herd Improvement scheme. A case-control approach was used to select a total of 126 herds from the first (top group - cases) and fourth quartiles (low group - controls) for intercalving interval.
Results We found that the estimated interval from calving to first mating was significantly different between groups (P = 0.03) and that the groups significantly differed in both their target for interval to first mating (P = 0.02) and their perceived optimum time for first mating (P = 0.04). Other factors associated with a longer intercalving interval included, use of embryo transfer programs (P = 0.08), younger managers (P = 0.02), fewer breedings per day (P = 0.01), a greater number of people detecting heats (P = 0.07), but less hours spent detecting heats while handling the cows (P = 0.11), and a failure to vaccinate bulls for campylobacteriosis (P = 0.14).
Conclusions Managers of herds with poorer reproductive performance did not intend to mate cattle as soon after calving as managers with better reproductive performance, were not as active in seeking veterinary advice on reproduction, and were attempting to treat reproductive diseases and disorders themselves.     

Surveillance and prevention in a non-affected state: Victoria

The equine influenza outbreak detected in August 2007 in New South Wales and Queensland did not enter Victoria, which was, however, considered at risk because of its sizable border with New South Wales. Accordingly, Victoria implemented a response plan to prevent disease entry and enable early detection of any disease. Horse movement restrictions, surveillance strategies and public awareness formed a large part of this response.     

Survey of the incidence and aetiology of mastitis on dairy farms in England and Wales

A survey of clinical and subclinical mastitis was carried out on 97 dairy farms in England and Wales, selected at random from members of a national milk recording scheme. The farmers were asked to collect aseptic milk samples from five consecutive cases of clinical mastitis and from five quarters with high somatic cell counts using a defined protocol, and they completed a questionnaire that included information on the cows sampled, the herd and the history of mastitis in the herd. The samples were collected throughout the year. The mean incidence of clinical mastitis was 47 cases per 100 cows per year (estimated from historic farm records) and 71 cases per 100 cows per year (estimated from the samples collected). Streptococcus uberis and Escherichia coli were isolated in pure culture from 23.5 per cent and 19.8 per cent, respectively, of the clinical samples; 26.5 per cent of the clinical samples produced no growth. The most common isolates from the samples with high cell counts were coagulase-negative staphylococci (15 per cent), S uberis (14 per cent) and Corynebacterium species (10 per cent). Staphylococcus aureus and coagulase-positive staphylococci together accounted for 10 per cent of the samples with high somatic cell counts; 39 per cent produced no bacterial growth.     

Lesions attributed to vaccination of sheep with Gudair for the control of ovine paratuberculosis: post farm economic impacts at slaughter

OBJECTIVE: To determine i) the prevalence of lesions at the site of vaccination with Gudair, and ii) the incidence of discounting of slaughtered sheep carcasses due to the presence of these lesions. DESIGN: A survey of the prevalence of injection lesions and actual discounts applied to 20 consignments of vaccinates slaughtered in abattoirs in New South Wales. PROCEDURE: Consignments of sheep previously vaccinated against ovine Johne's disease (OJD) were assessed on the slaughter chain for the prevalence of vaccination site lesions and any costs associated with carcass trimming were estimated. In addition a telephone survey was conducted to determine the experiences and risk attitudes of 8 abattoirs in south east New South Wales likely to have previously processed vaccinates. RESULTS: The prevalence of lesions observed was 18% for adult (mutton) and 65% for lamb carcasses. The value of the trim removed was insignificant, the labour cost of its removal was nil and no carcass was downgraded to a lower value grade. CONCLUSION: Under the market conditions existing at the time the study was conducted, in sheep vaccinated at the recommended site high on the neck, it is unlikely that OJD vaccination site lesions will be a significant cost to producers or the processing industry and will represent only a very small proportion of the total cost of OJD control by vaccination.     

Farmer reported prevalence and factors associated with contagious ovine digital dermatitis in Wales: A questionnaire of 511 sheep farmers

In 2012, 2000 questionnaires were sent to a random sample of Welsh sheep farmers. The questionnaire investigated farmers’ knowledge and views on contagious ovine digital dermatitis (CODD) – an emerging disease of sheep responsible for causing severe lameness, welfare and production problems. The overall response rate was 28.3% with a usable response rate of 25.6%. The between farm prevalence of CODD was 35.0% and the median farmer estimated prevalence of CODD was 2.0%. The disease now appears endemic and widespread in Wales. Furthermore, there has been a rapid increase in reports of CODD arriving on farms since the year 2000. Risk factors for CODD identified in this study include the presence of bovine digital dermatitis (BDD) in cattle on the farm and larger flocks. Farmers also consider concurrent footrot/interdigital dermatitis, buying in sheep, adult sheep, time of year and housing to be associated with CODD. Further experimental research is necessary to establish whether these observations are true associations.     

Ovine Johne's disease in Australia--the first 20 years

OBJECTIVE: To review the history of ovine Johne's disease in Australia. PROCEDURE: Relevant publications and reports were identified and reviewed to document the spread of ovine Johne's disease (OJD) from 1980 until the end of 2000, as well as the response of industry and government to the spread of this disease. RESULTS: OJD was first diagnosed in the central tablelands region of New South Wales in 1980. Since then it has spread, either from the initial focus or through separate introductions so that by December 2000 a total of 823 infected flocks had been identified. Cases have been confirmed in New South Wales, Victoria, the Australian Capital Territory, on Flinders Island in Tasmania, on Kangaroo Island in South Australia and in Western Australia. In early 1999, agreement was reached to fund and implement a 6-year, $40 million National OJD Control and Evaluation Program (NOJDP). This program is jointly funded by the sheep industries (national and state), and Commonwealth and State governments, and is managed by Animal Health Australia. CONCLUSION: A national program is now in place to support the control of OJD and research to determine the feasibility and cost-effectiveness of eradication. The development of new diagnostic techniques, such as abattoir surveillance and pooled faecal culture, provide opportunities to refine surveillance strategies and to define better the distribution and prevalence of this disease, as required by the national program. Effective control measures, combined with quality surveillance data, will enable informed decision making for the future national management of OJD.     

Snake envenomation in dogs in New South Wales

OBJECTIVE: To obtain baseline data on the prevalence of elapid snake envenomation in dogs presented to veterinary practices in New South Wales and to assess attitudes of veterinarians to this clinical entity. PROCEDURE: A mailed questionnaire, sent to all veterinary clinics within New South Wales, was utilised to collect epidemiological information regarding elapid snake envenomation in dogs. RESULTS: A response rate of 68% was obtained and a yearly prevalence of snake envenomation in dogs across New South Wales veterinary clinics was estimated as 0.31%. The most common species reported to be responsible for envenomation within NSW was the Red Bellied Black snake (Pseudechis porphyriacus) followed by the Brown snake (Pseudonaja textilis) and then Tiger snake (Notechis scutatus). The reported envenomation syndromes caused by these common snake species were perceived to be similar for Brown and Tiger snakes but differed for Red Bellied Black snakes. Diagnosis of snake envenomation was based predominantly on the recognition of clinical signs. Specific diagnostic tests, such as venom detection kits, were used infrequently. The most common treatment was reported to be a combination of intravenous fluid therapy and antivenom, and monitoring of response to this treatment was usually through assessment of clinical signs. Survival after antivenom administration was reported to be highest for Red Bellied Black snake species. Survival was perceived to be associated with time between envenomation and presentation to the veterinary clinic and with antivenom administration. CONCLUSIONS: Current attitudes and perceptions of veterinarians have been defined. Diagnosis of species-specific snake envenomation is shown to be made on the basis of clinical signs which are, however, reported as similar for each species. Clearer definition of these envenomation syndromes and identification of accessible diagnostic testing procedures are needed.     

Johne's disease in sheep

SUMMARY Johne's disease was identified in sheep flocks on 6 farms in one area of the central tablelands of New South Wales. The sources of infection were not determined and no common source of all infections was identified. The disease was not diagnosed in cattle that were run on 4 of the farms.     

The distribution of antibodies to Border disease virus among sheep in England and Wales.

Within a sample of the sheep population of England and Wales, 10.8 per cent of 3506 individuals had immunodiffusion test antibody to bovine viral diarrhoea mucosal disease virus antigen. There were marked differences between various geographical regions in the proportion of sheep with antibody, and Border disease may be more common in some areas than disease records indicate.     

The estimated prevalence of Johne's disease infected sheep flocks in Australia

OBJECTIVE: To estimate the likely geographical distribution and flock-prevalence of ovine Johne's disease (OJD) in Australia. DESIGN: A cross-sectional study design was used. PROCEDURE: The results of abattoir surveillance for OJD carried out during 2000 were analysed to estimate the prevalence of infected flocks in three regions of New South Wales and in other States. A Bayesian approach was used to adjust apparent prevalence estimates for the assumed flock-sensitivity and flock-specificity of abattoir surveillance, and to allow for uncertainty about the true values of these measures. RESULTS: The 95% probability limits for flock-prevalence at 31 December 2000 were 0.04%-1.5%, 8%-15% and 29%-39% for low, moderate and high prevalence regions of New South Wales respectively. The other States generally had an upper 97.5% probability limit of about 1% or less. Based on these estimates about 6 to 10% of flocks in New South Wales and 2.4 to 4.4% of flocks Australia-wide are likely to be infected. CONCLUSION: This study suggests that OJD has a highly clustered distribution in Australia, and provides estimates of the prevalence of infected flocks by State or region. Based on this analysis there were probably between 2000 and 3700 infected flocks in Australia at 31 December 2000, with more than 80% of these in a relatively small geographic area of central and southern New South Wales. Some States, such as Queensland and Western Australia, may have a prevalence equal or close to 0%, however the technique used was unable to demonstrate the absence of infection in these States with the intensity of surveillance undertaken to date.     

Cross-sectional study of risk factors for the clinical expression of ovine Johne's disease on New South Wales farms

OBJECTIVE: To explore the environmental and management risk factors that promote the clinical expression of ovine Johne's disease on farms in New South Wales. DESIGN: Cross-sectional study. PROCEDURE: A questionnaire about the farm, flock and their management was mailed to all farmers known to keep infected sheep in the area zoned residual for ovine Johne's disease in New South Wales. The resultant data were analysed by multivariate statistical methods, specifically examining the factors associated with farmers reporting some mortality due to ovine Johne's disease; the reported annual incidence of ovine Johne's disease-associated mortality; the youngest age at which sheep die from ovine Johne's disease; whether scouring was a feature of the disease; and the season of peak mortality from ovine Johne's disease. RESULTS: Fine wool Merino sheep were more likely to die from ovine Johne's disease than other sheep types. Mortality was higher on farms with light sandy soils and those with a high proportion of improved pastures containing subterranean clover. Winter shearing was also associated with clinical expression. The time that the infection had been present on a farm was not strongly associated with mortality. Higher stocking density, high rainfall and access to open water, factors that are believed to aid transmission, were not found to be influential. CONCLUSION: Clinical expression appears to be principally associated with light infertile soils and their associated pastures and pasture improvement practices which may lead to micronutrient deficiencies or imbalances. Genetic effects are also important and are likely to be exacerbated by physiological stressors, such as winter shearing.     

Specificity of absorbed ELISA and agar gel immuno-diffusion tests for paratuberculosis in goats with observations about use of these tests in infected goats

OBJECTIVE: To determine the specificity of serological tests that are currently used in veterinary diagnostic laboratories in Australia for detection of Mycobacterium avium subsp paratuberculosis infection in goats. DESIGN: A laboratory study. PROCEDURE: Four tests were studied, comprising AGID with M. a. paratuberculosis antigen derived from cattle isolates of caprine or bovine origin, the EMAI caprine Johne's disease absorbed ELISA and the CSL PARACHEK Johne's absorbed EIA. The specificities of AGID and ELISA for paratuberculosis (Johne's disease) were estimated after examining a panel of 1000 serum samples collected from goats in Western Australia, a region free of paratuberculosis. In addition a comparison was made of test performance in a small number of paratuberculous goats from New South Wales using sera from two archival collections. RESULTS: The specificity of the AGID tests was 100% while the specificities of the two absorbed ELISA were 99.7 to 99.8% at appropriate positive-negative cut-offs. Based on testing the small sample of sera from infected goats, the absorbed ELISA tests detected about twice as many goats with Johne's disease as the AGID. Each test detected paratuberculous animals regardless of whether infection was caused by cattle or sheep strains of M. a. paratuberculosis. CONCLUSIONS: Both ELISA and AGID tests for paratuberculosis have high specificity and can be used in a market assurance program without risk of generating large proportions of false positive test results. However, the results suggested the ELISA is more sensitive for detection of infected goats and should be used in preference to the AGID. The two formats of ELISA evaluated in this study have similar characteristics and could be used in paratuberculosis control programs for the goat industries, but further data on sensitivity would increase confidence in their application.     

Longitudinal study describing the clinical signs observed in horses naturally infected with equine influenza

We describe the clinical signs and disease course during an outbreak of equine influenza (EI) in na?ve horses in a police stables in Sydney, New South Wales, Australia.     

The southward spread of buffalo fly (Haematobia irritans exigua) in eastern Australia and its survival through a severe winter

The southward spread of buffalo fly (Haematobia irritans exigua) in coastal eastern Australia from Bororen, Queensland in 1974 to Coffs Harbour, New South Wales in 1982 is documented. Surveys after a cold, dry winter in 1982 recorded overwintering sites and subsequent spread of flies in southern Queensland and northern New South Wales. Buffalo fly overwintered at several places in the Maryborough-Bauple districts and further north. Overwintering also occurred in the Currumbin Valley-Mudgeeraba area on the Queensland-New South Wales border. Other infestations detected early in the season and believed to have arisen from local overwintering populations were observed at Kin Kin, Mount Tamborine and Flinders Peak. By May 1983 flies had recolonised much of coastal south eastern Queensland, and as far south as Ballina and west to the Richmond Range in New South Wales. Implications of these findings for control are discussed.